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Numrering	Referens	Omslagsbild	Hitta
1.	Björck, Svante, et al. (författare) Current global warming appears anomalous in relation to the climate of the last 20 000 years 2011 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 48:Climate Research 1, s. 5-11 Konferensbidrag (refereegranskat)abstract To distinguish between natural and anthropogenic forcing, the supposedly ongoing global warming needs to be put in a longer, geological perspective. When the last ca. 20 000 yr of climate development is reviewed, including the climatically dramatic period when the Last Ice Age ended, the Last Termination, it appears that the last centuries of globally rising temperatures should be regarded as an anomaly. Other, often synchronous climate events are not expressed in a globally consistent way, but rather are the expression of the complexities of the climate system. Due to the often poor precision in the dating of older proxy records, such a statement will obviously be met with some opposition. However, as long as no globally consistent climate event prior to today’s global warming has been clearly documented, and considering that climate trends during the last millennia in different parts of the world have, in the last century or so, changed direction into a globally warming trend, we ought to regard the ongoing changes as anomalies, triggered by anthropogenically forced alterations of the carbon cycle in the general global environment.
2.	Bunnefeld, Nils (författare) The normalized difference vegetation index (NDVI): unforeseen successes in animal ecology 2011 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 46, s. 15-27 Forskningsöversikt (refereegranskat)abstract This review highlights the latest developments associated with the use of the Normalized Difference Vegetation Index (NDVI) in ecology. Over the last decade, the NDVI has proven extremely useful in predicting herbivore and non-herbivore distribution, abundance and life history traits in space and time. Due to the continuous nature of NDVI since mid-1981, the relative importance of different temporal and spatial lags on population performance can be assessed, widening our understanding of population dynamics. Previously thought to be most useful in temperate environments, the utility of this satellite-derived index has been demonstrated even in sparsely vegetated areas. Climate models can be used to reconstruct historical patterns in vegetation dynamics in addition to anticipating the effects of future environmental change on biodiversity. NDVI has thus been established as a crucial tool for assessing past and future population and biodiversity consequences of change in climate, vegetation phenology and primary productivity.
3.	Chen, D., et al. (författare) Comparison of the Thornthwaite method and pan data with the standard Penman-Monteith estimates of reference evapotranspiration in China 2005 Ingår i: Climate Research (CR). - 0936-577X .- 1616-1572. ; 28, s. 123-132 Tidskriftsartikel (refereegranskat)
4.	Creutzig, Felix, et al. (författare) Demand-side solutions to climate change mitigation consistent with high levels of wellbeing 2021 Ingår i: Climate Research (CR). - : Research Square Platform LLC. - 0936-577X .- 1616-1572. Tidskriftsartikel (refereegranskat)abstract Climate mitigation solutions are often evaluated in terms of their costs and potentials. This accounting, however, shortcuts a comprehensive evaluation of how climate solutions affect human well-being, which, at best, may only be crudely related to cost considerations. Here, we systematically list key sectoral mitigation options on the demand side, and categorize them into avoid, shift and improve categories. We show that these options, bridging socio-behavioral, infrastructural and technological domains, can reduce counterfactual sectoral emissions by 50-80% in end use sectors. Based on expert judgement and literature survey, we then evaluate 324 combinations of wellbeing outcomes and demand side options. We find that these are largely beneficial in improving wellbeing across all measures combined (76% have positive, 22% neutral, and 2.4% have negative effects), even though confidence level is low in the social dimensions of wellbeing. Implementing demand-side solution requires i) an understanding of malleable not fixed preferences, ii) consistently measuring and evaluating constituents of wellbeing, and iii) addressing concerns of incumbents in supply-side industries. Our results shift the emphasis in the climate mitigation solution space from supply-side technologies to demand-side service provision.
5.	Eckersten, Henrik (författare) Changing regional weather-crop yield relationships across Europe between 1901 and 2012 2016 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 70, s. 195-214 Tidskriftsartikel (refereegranskat)abstract Europe is, after Asia, the second largest producer of wheat in the world, and provides the largest share of barley. Wheat (and to a similar extent, barley) production in Europe increased by more than 6-fold during the 20th century. During the first half of the 20th century, this was driven by expanding the harvested area. This was followed, from the mid-20th century, by a massive increase in productivity that in many regions has stalled since 2000. However, it remains unclear what role climatic factors have played in these changes. Understanding the net impact of climatic trends over the past century would also aid in our understanding of the potential impact of future climate changes and in assessments of the potential for adaptation across Europe. In this study, we compiled information from several sources on winter wheat and spring barley yields and climatological data from 12 countries/regions covering the period from 1901-2012. The studied area includes the majority of climatic regions in which wheat and barley are grown (from central Italy to Finland). We hypothesized that changes in climatic conditions have led to measurable shifts in climate-yield relationships over the past 112 yr, and that presently grown wheat and barley show a more pronounced response to adverse weather conditions compared to crops from the early 20th century. The results confirm that climate-yield relationships have changed significantly over the period studied, and that in some regions, different predictors have had a greater effect on yields in recent times (between 1991 and 2012) than in previous decades. It is likely that changes in the climate-yield relationship at the local level might be more pronounced than those across the relatively large regions used in this study, as the latter represents aggregations of yields from various agroclimatic and pedoclimatic conditions that may show opposing trends.
6.	Eckersten, Henrik, et al. (författare) Crop yield trends in relation to temperature indices and a growth model 2010 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 42, s. 119-131 Tidskriftsartikel (refereegranskat)abstract Annual variability and trends in winter wheat yields were evaluated for relationships to climate in 6 long-term experiments (in total 1915-2005) and regionally in 3 counties (1965-2008) in southern and central Sweden. The annual yield was predicted as function of a climate index and year. Alternative indices were used based on either monthly temperatures or yield predicted by a simple weather-driven crop growth simulation model. The main results were as follows. (1) The yield predictions were better for regions than for the long-term experiments. (2) The time variable accounted for more of the yield trend in regions than in the experiments, and more in southern than in central Sweden. (3) The models based on a simple temperature index were often better yield predictors than the growth model. (4) The relations to winter temperatures became gradually weaker after ca. 1970. (5) The yield relation to simple temperature indices differed between locations, similarly for experimental and regional yields. (6) The strongest influence of climate was estimated by means of the growth model predictions of regional yields in Gotland County. (7) The fraction of regional yield trends (1965-1996; ranging from 57 to 90 kg ha(-1) yr(-1)) that could be attributed to climate was estimated greatest in the Gotland region (27 to 64%). For climate change assessments of winter wheat yield in central Sweden, the growth model considering temperature, radiation and water conditions during spring and summer would also need to include processes of overwintering.
7.	Ekström, Marie, et al. (författare) Synoptic pressure patterns associated with major wind erosion events in southern Sweden (1973-1991) 2002 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 23:1, s. 51-66 Tidskriftsartikel (refereegranskat)abstract Wind erosion causes severe damage on sandy soils in agricultural areas of north-west Europe. The weather conditions during erosion events are the result of the general atmospheric circulation and are key components in the erosion process. Principal component analysis (PCA) in combination with a non-hierarchical cluster analysis was conducted on de-seasonalized daily mean-sea-level pressure (MSLP) patterns of north-western Europe between 1973 and 1991 to determine the main synoptic types associated with wind erosion on sugar beet fields in Scania, southern Sweden. Cluster analysis of the PCA scores indicated that the observations should be grouped into 14 classes for which average MSLP patterns were computed. To assess the relationship between the patterns and wind erosion, 2 indices were computed. Index of Occurrence (10) is the ratio between the occurrence of the patterns during days with wind erosion and the occurrence during the entire wind erosion season. Index of Erosion Severity (IES) is computed by weighting the 10 with the area damaged by wind erosion associated with each pressure pattern. The IES identifies 2 pressure patterns that have significantly larger values than the other patterns. The most important is a pattern showing easterly flow over Scania, associated with 74 % (912 ha of 1235 ha) of the total damage in the study area. The second most important is a pattern showing westerly flow over Scania, associated with 5 % (63 ha) of the total damage. Both pressure patterns contain strong pressure gradients (in different directions) located over Scania. Depending on the location of the maximum gradient these patterns could be associated with wind erosion in other regions of north-western Europe.
8.	Emmanuel, R, et al. (författare) Influence of urban morphology and sea breeze on hot humid microclimate: the case of Colombo, Sri Lanka 2006 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 30:3, s. 189-200 Tidskriftsartikel (refereegranskat)abstract Urbanisation leads to increased thermal stress in hot-humid climates due to increased surface and air temperatures and reduced wind speed. We examined the influence of urban morphology and sea breeze on the microclimate of Colombo, Sri Lanka. Air and surface temperatures, humidity and wind speed were measured at 1 rural and 5 urban sites during the warmest season. The urban sites differed in their height to width (H/W) ratio, ground cover and distance to the sea. Intra-urban air temperature differences were greatest during the daytime. A maximum intra-urban difference of 7 K was recorded on clear days. Maximum temperatures tended to decrease with increasing H/W ratio and proximity to the sea. All urban sites experienced a nocturnal urban heat island (UHI) when the sky was clear or partly cloudy. The temperature differences between sunlit and shaded urban surfaces reached 20 K, which shows the importance of shade in urban canyons (reducing long-wave radiation from surfaces). Within the urban areas, the vapour pressure was high (> 30 hPa) and showed little diurnal variation. Wind speeds were low (< 2 m s(-1)) and tended to decrease with increasing H/W ratio. Shading is proposed as the main strategy for lowering air and radiant temperatures; this can be achieved by deeper canyons, covered walkways and shade trees. It is also suggested to open up wind corridors perpendicular to the sea to facilitate deeper sea breeze penetration.
9.	Esper, Jan, et al. (författare) Environmental drivers of historical grain price variations in Europe 2017 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 72:1, s. 39-52 Tidskriftsartikel (refereegranskat)abstract Grain price (GP) volatility has been a central constituent of European commerce, with fluctuations in barley, rye and wheat prices having been carefully documented over centuries. However, a thorough understanding of the climatic and environmental drivers of long-term GP variations is still lacking. Here, we present a network of historical GP records from 19 cities in central and southern Europe for the 14th to 18th centuries. Spatial variability at interannual to multidecadal scales within this network was compared with reconstructed warm-season temperatures and hydro climatic conditions. We show that European GPs are tightly coupled with historical famines and that food shortages coincide with regional summer drought anomalies. Direct correlations between historical GP and reconstructed drought indices are low, hardly exceeding r = -0.2. Yet if the analysis is focused on extreme events, the climatic controls on high-frequency price variations become obvious: GPs were exceptionally high during dry periods and exceptionally low during wet periods. In addition, we find that GP variations were affected by temperature fluctuations at multidecadal timescales. The influence of summer temperatures is particularly strong over the 1650-1750 period, subsequent to the Thirty Years' War, reaching r = -0.40 at the European scale. This observation is supported by the lack of correlation among regional GP clusters during the period of hostilities and increased inter-regional correlation thereafter. These results demonstrate that the exchange of goods and spatial coherence of GP data in Europe were controlled both by socio-political and environmental factors, with environmental factors being more influential during peacetime.
10.	Gallego-Sala, Angela, et al. (författare) Bioclimatic envelope model of climate change impacts on blanket peatland distribution in Great Britain 2010 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 45:1, s. 151-162 Tidskriftsartikel (refereegranskat)abstract Blanket peatlands are rain-fed mires that cover the landscape almost regardless of topography. The geographical extent of this type of peatland is highly sensitive to climate. We applied a global process-based bioclimatic envelope model, PeatStash, to predict the distribution of British blanket peatlands. The model captures the present areal extent (Kappa = 0.77) and is highly sensitive to both temperature and precipitation changes. When the model is run using the UKCIP02 climate projections for the time periods 2011–2040, 2041–2070 and 2071–2100, the geographical distribution of blanket peatlands gradually retreats towards the north and the west. In the UKCIP02 high emissions scenario for 2071–2100, the blanket peatland bioclimatic space is ~84% smaller than contemporary conditions (1961–1990); only parts of the west of Scotland remain inside this space. Increasing summer temperature is the main driver of the projected changes in areal extent. Simulations using 7 climate model outputs resulted in generally similar patterns of declining aereal extent of the bioclimatic space, although differing in degree. The results presented in this study should be viewed as a first step towards understanding the trends likely to affect the blanket peatland distribution in Great Britain. The eventual fate of existing blanket peatlands left outside their bioclimatic space remains uncertain.
11.	Good, P., et al. (författare) Non-linear regional relationships between climate extremes and annual mean temperatures in model projections for 1961-2099 over Europe 2006 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 31:1, s. 19-34 Tidskriftsartikel (refereegranskat)abstract A simple method is tested for scaling climate-extreme results from high resolution regional climate models (RCMs) to time-periods and emission scenarios for which the RCMs have not been run. The 30 yr mean relationships between indicators of extremes (IoEs) and annual mean daily maximum temperature (T-xa) are investigated. Such relationships from the UK Met Office Hadley Centre RCM HadRM3P, along with temperatures from the global climate model HadCM3, are used to scale IoEs to other time periods and scenarios. This is tested for selected indicators of heat-wave and drought over Europe for the period 1961-2099. Curvature is demonstrated in the relationships between these quantities and T-xa. Such non-linearities are shown to have a large potential effect on how these climate extremes are likely to evolve during the century, as well as their sensitivity to emissions. A broad picture of possible changes in European heat-wave and drought severity is presented. For drought over the Mediterranean and western Europe, a very clear positive curvature in the relationship between drought length and annually averaged temperature is found. (This feature is also common in a brief study of 6 other RCMs.) It suggests a rapid increase in drought length towards the end of the century, and a strong sensitivity to the emission scenario. Extended summer dry spells are projected to become a much more regular feature of western European climates. For European heatwaves, we find a slightly earlier onset of increases in heat-wave severity and a reduced sensitivity to emission scenarios than might be expected from a more straightforward interpretation of the Hadley Centre model results. This is linked with extreme dryness occurring at high summer in all years by the end of the century, but was not evident in the 6 other RCMs studied. Based on these results, suggestions are made for choices of future RCM experiments.
12.	Gunnarson, Björn E., et al. (författare) Legacies of pre-industrial land use can bias modern tree-ring climate calibrations 2012 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 53:1, s. 63-76 Tidskriftsartikel (refereegranskat)abstract In Scandinavia, dendrochronological reconstructions of past climate have mostly been based on tree-ring data from forests in which there has been, supposedly, very little or no human impact. However, human land use in sub-alpine forests has a substantially longer history and more profound effects on the forest ecosystems than previously acknowledged. Therefore, to assess human influence on tree-ring patterns over the last 500 yr, we have analyzed tree-ring patterns using trees from 2 abandoned Sami settlements and a reference site with no human impact-all situated in the Tjeggelvas Nature Reserve in north-west Sweden. The hypothesis was that land use legacies have affected tree-ring patterns, and in turn, the resulting palaeoclimate inferences that have been made from these patterns. Our results show that climate signals are strongest at the reference site and weakest at one of the settlement sites. From the 1940s to the present, tree growth at this settlement site has been significantly lower than at the reference site. Lower tree growth at old settlements may have resulted from rapid changes in the traditional land use, or following the abrupt change when the settlements were abandoned. Without site-specific know ledge of past land use, there is a high risk of accidently sampling trees that have been affected by human-induced disturbances in the past. This may create bias in the climate signals inferred from such trees, and hence bias the outcome of climate reconstructions. We therefore recommend sampling several separate sites in study areas to improve the robustness of inferences.
13.	Guo, Guoyang, et al. (författare) Increasing intrinsic water-use efficiency over the past 160 years does not stimulate tree growth in southeastern China 2018 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 76:2, s. 115-130 Tidskriftsartikel (refereegranskat)abstract © 2018 Inter-Research. Understanding the responses of tree growth and intrinsic water-use efficiency (iWUE) to anthropogenic CO2 increase and climate warming provides important benchmarks for evaluating future forest dynamics under different scenarios of warming and CO2 changes. Relative to the short period of instrumental data of the past few decades, long-term tree-ring width and stable carbon isotopic (δ13C) data are invaluable in fully comprehending their interactions during the entire industrial era, since ~1850. Here, we present a tree-ring width chronology (1856 to 2015) and Δ13C series (1876-2015) of Pinus massoniana for Yongtai county of Fujian province, in humid subtropical China, a 'green island' relative to other dry subtropical areas of the world. Tree growth was limited by precipitation of the hydrological year (previous November to current October) (r = 0.568, p < 0.001), and the stable carbon isotope discrimination (Δ13C) was strongly correlated with relative humidity in September-October (r =-0.677, p < 0.001) of the current growing season. We found that the iWUE increased by 40.9% since 1876. Specifically, we found that the ci:ca ratio decreased during the study period whereas intercellular CO2 concentration (ci) increased. The negative relationship between basal area increment (BAI) and iWUE indicated that increasing iWUE may not lead to long-term enhancement of tree growth. Our results indicated a drought-induced limitation to tree growth in response to rising CO2, and that trees may mitigate the negative effects of a decrease in water availability through a reduction in stomatal conductance.
14.	Hanssen-Bauer, I., et al. (författare) Statistical downscaling of climate scenarios over Scandinavia 2005 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 29:3, s. 255-268 Tidskriftsartikel (refereegranskat)abstract Studies from recent years involving development and application of statistical downscaling models for Scandinavia (mainly Norway and Sweden) are reviewed. In most of the studies linear techniques were applied. Local temperature and/or precipitation were predictands in a majority of the studies. Large-scale temperature fields, either from 2 m or 850 hPa, were found to be the best predictors for local temperature, while a combination of atmospheric circulation indices and tropospheric humidity information were the best predictors for local precipitation. Statistically downscaled temperature scenarios for Scandinavia differ depending on climate model, emission scenario and downscaling strategy. There are nevertheless several common features in the temperature scenarios. The warming rates during the 21st century are projected to increase with distance from the coast and with latitude. In most of Scandinavia higher warming rates are projected in winter than in summer. For precipitation, the spread between different scenarios is larger than for temperature. A substantial part of the projected precipitation change is connected to projected changes in atmospheric circulation, which differ considerably from one model integration to another. A tendency for increased large-scale humidity over Scandinavia still implies that projections for the 21st century typically indicate increased annual precipitation. This tendency is most significant during winter. In northern Scandinavia the projections tend to show increased precipitation also during summer, but several scenarios show reduced summer precipitation in parts of southern Scandinavia. Comparisons with results from global and regional climate models indicate that both regional modeling and statistical downscaling add value to the results from the global models.
15.	Hedenström, Anders, et al. (författare) Migration speed and scheduling of annual events by migrating birds in relation to climate change 2007 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 35:1-2, s. 79-91 Tidskriftsartikel (refereegranskat)abstract Empirical evidence for changed timing of migration in birds is emerging from both American and Euro-African migration systems. These changes are usually interpreted as a consequence of changes in climate. Responses in timing of migration and breeding may differ among species, and the adaptive significance is not well understood. There is a lack of theoretical understanding about time-shifts in life-history events due to climatic changes. In the present paper, we use 2 separate modelling approaches to investigate the effects of climate change on migration. We first use a simple model of flight speed and foraging to explore which factors may influence migration speed and stopover itinerary. Our second approach derives predictions based on an annual routine model, where behavioural strategies regarding timing of migration, breeding, moult and number of breeding attempts are modelled in an environment comprising 4 locations (breeding and wintering sites and 2 stopover sites). This approach takes account of interrelationships between behaviours and seasons as a step towards realistic modelling of migratory connectivity. Departure from the wintering site is advanced in relation to the advancement of spring if the moult is in summer, but not so for species with a winter moult, while arrival at the breeding site is advanced for both moult scenarios. Timing of breeding and number of successful broods were also affected by spring advancement, while start of moult is relatively unaffected by climate change. These optimal solutions under the modelled set of parameters are discussed with respect to current knowledge of the mechanisms underlying seasonal timing in birds.
16.	Hesselbjerg Christensen, Jens, et al. (författare) Weight assignment in regional climate models 2010 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 44:2-3, s. 179-194 Tidskriftsartikel (refereegranskat)abstract An important new development within the European ENSEMBLES project has been to explore performance-based weighting of regional climate models (RCMs). Until now, although no weighting has been applied in multi-RCM analyses, one could claim that an assumption of ‘equal weight’ was implicitly adopted. At the same time, different RCMs generate different results, e.g. for various types of extremes, and these results need to be combined when using the full RCM ensemble. The process of constructing, assigning and combining metrics of model performance is not straightforward. Rather, there is a considerable degree of subjectivity both in the choice of metrics and on how these may be combined into weights. We explore the applicability of combining a set of 6 specifically designed RCM performance metrics to produce one aggregated model weight with the purpose of combining climate change information from the range of RCMs used within ENSEMBLES. These metrics capture aspects of model performance in reproducing large-scale circulation patterns, meso-scale signals, daily temperature and precipitation distributions and extremes, trends and the annual cycle. We examine different aggregation procedures that generate different inter-model spreads of weights. The use of model weights is sensitive to the aggregation procedure and shows different sensitivities to the selected metrics. Generally, however, we do not find compelling evidence of an improved description of mean climate states using performance-based weights in comparison to the use of equal weights. We suggest that model weighting adds another level of uncertainty to the generation of ensemble-based climate projections, which should be suitably explored, although our results indicate that this uncertainty remains relatively small for the weighting procedures examined.
17.	Jonzén, Niclas, et al. (författare) Bird migration and climate - Introduction 2007 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 35:1-2, s. 1-3 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
18.	Jonzén, Niclas, et al. (författare) Bird migration and climate: the general picture and beyond 2007 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 35:1-2, s. 177-180 Tidskriftsartikel (refereegranskat)
19.	Kjellström, Erik, et al. (författare) Emerging regional climate change signals for Europe under varying large-scale circulation conditions 2013 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 56:2, s. 103-119 Tidskriftsartikel (refereegranskat)abstract A large ensemble of regional climate model projections was investigated regarding if and when they show an emergence of significant climate change signals in seasonal temperature and precipitation within Europe. The influence of the North Atlantic Oscillation (NAO), as simulated in the projections, was investigated. In most parts of Europe, the projections indicate robust emergence of temperature change in the first 2 decades of the 21st century, typically earlier for summer than for winter. For precipitation changes, signals generally emerge much later than for temperature. For Europe as a whole, the precipitation signals tend to emerge some 40 to 60 yr later than the temperature signals. In some sub-regions, robust signals for precipitation are not found within the studied period, i.e. until 2100. Some sub-regions, notably the Mediterranean area and Scandinavia, show different behaviour in some aspects compared to the ensemble-based results as a whole. NAO has some influence on the temperature change signals, which emerge earlier in winter for some models and regions if NAO is accounted for. For summer temperatures, the influence of NAO is less evident. Similarly, for precipitation, accounting for NAO leads to an earlier emergence in some regions and models. Here, we find an impact for both summer and winter.
20.	Knudsen, Endre, et al. (författare) Characterizing bird migration phenology using data from standardized monitoring at bird observatories 2007 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 35:1-2, s. 59-77 Forskningsöversikt (refereegranskat)abstract Long-term data from standardized monitoring programmes at bird observatories are becoming increasingly available. These data are frequently used for detecting changes in the timing of bird migration that may relate to recent climate change. We present an overview of problematic issues in the analysis of these data, and review approaches to and methods for characterizing bird migration phenology and its change over time. Methods are illustrated and briefly compared using autumn data on garden warbler Sylvia borin from a standardized mist-netting programme at Lista bird observatory, southern Norway. Bird migration phenology is usually characterized rather coarsely using a small number of sample statistics such as mean, median and selected quantiles. We present 2 alternative approaches. Smoothing methods describe the within-season pattern in the data at an arbitrary level of detail, while fitting a parametric seasonal distribution curve offers a coarse description of migration phenology relatively robust to sampling effects. Various methods for analyzing linear trends in the timing of bird migration are reviewed and discussed. Exploratory studies using long-term data gathered at bird observatories can yield more detailed insight into the phenomenon of bird migration and how phenologies relate to climate. Methodological advances are needed, particularly in order to better characterize the shape of phenological distributions and separate between sampling effects and 'true' phenology.
21.	Lelovics, Enikő, et al. (författare) Design of an urban monitoring network based on local climate zone mapping and temperature pattern modelling 2014 Ingår i: Climate Research (CR). - : Inter Research. - 0936-577X .- 1616-1572. ; 60:1, s. 51-62 Tidskriftsartikel (refereegranskat)abstract The recently developed Local Climate Zones (LCZ) classification system was initially not designed for mapping, but to classify temperature observation sites. Nevertheless, as a need arose to characterize areas based on their distinct thermal climate, utilizing LCZ classes for mapping was a logical step. The objectives of this study were (1) to develop GIS methods for the calculation of different surface parameters required for LCZ classification; (2) to identify and delineate the LCZ types within the study area using the calculated parameters; and (3) to select representative station sites for an urban monitoring network utilizing both the mapped LCZs and the modelled mean annual temperature surplus pattern in Szeged, Hungary. The study used remotely sensed data, maps and GIS databases of the city and its surroundings. The basic area of calculation was the lot area polygon, consisting of a building and its close vicinity. Adjoining polygons classified with identical or similar parameters were merged to obtain LCZs of appropriate size. As a result, 6 built LCZ types were distinguished in the studied urban area. The temperature pattern in the city was provided by an empirical model. The siting of stations took both the LCZ map and the modelled temperature pattern into account. The lampposts onto which the stations were to be mounted were determined by field surveys. The bias between the temperature pattern interpolated from the 24 stations and the initially estimated distribution by the model was found to be small. LCZ mapping is the first step in the development of urban climate maps (UCMs) that carry information on the spatial distribution and magnitude of the heat stress (thermal loads) and on the ventilation ability (dynamical potential) of different urban areas.
22.	Li, Peng, et al. (författare) Radiation budget in RegCM4 : simulation results from two radiative schemes over the South West Indian Ocean 2021 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 84, s. 181-195 Tidskriftsartikel (refereegranskat)abstract One way to estimate solar resources required by the solar industry is via regional climate models (RCMs), which provide a comprehensive and physically based state-of-the-art description of the atmosphere and its interactions with the Earth’s surface. Here we describe the first application of RCM simulations with Regional Climate Model Version 4 (RegCM4) for radiation fluxes over the South West Indian Ocean (SWIO). We analyzed the performance of RegCM4 on radiation fluxes, especially its radiative schemes presentation, which could provide basic information for surface solar radiation temporal-spatial variability analysis with RegCM4 over SWIO region. We used ERA-Interim reanalysis data for the period 2000-2005 to drive RegCM4 to simulate the radiation budget and associated parameters such as cloud cover, precipitation and surface temperature, over Southern Africa and the SWIO with a horizontal resolution of 50 km. The 2 existing available radiation schemes were tested and evaluated: (1) the default radiation scheme of the NCAR Community Climate Model Version 3 (CCM); and (2) the recently implemented Rapid Radiation Transfer Model (RRTM). To analyze the behavior of the radiation schemes and their impact on the surface climate, model outputs were validated against available satellite and reanalysis data. A comparison of the seasonal radiation budget as simulated by RegCM4-CCM and RegCM4-RRTM at the surface and at the top of the atmosphere showed good qualitative agreement. RegCM4 with the RRTM scheme generally better simulates the radiation budget and cloud cover over the whole domain with regard to the reference data than RegCM4 with the CCM scheme; RRTM could therefore be chosen as the radiative scheme in subsequent studies of surface solar radiation by RegCM4.
23.	Lindén, Jenny, et al. (författare) Determination of the urban heat island intensity in villages and its connection to land cover in three European climate zones 2018 Ingår i: Climate Research (CR). - 0936-577X .- 1616-1572. ; :76, s. 1-15 Tidskriftsartikel (refereegranskat)abstract Although urban heat islands (UHIs) have been found in many cities throughout the world, work on smaller settlements is still limited, especially concerning variations connected to climate zones. Meteorological stations are often regarded as rural when located in a village or small town, and any temperature bias is assumed negligible. In this paper, we therefore present air temperature variations and their connection to land cover in 3 European villages, boreal Haparanda, temperate Geisenheim, and Mediterranean Cazorla, all of them hosting long temperature records that might be biased. The villages were equipped with temperature sensors, and the surrounding areas were digitized to compare UHI effects and to evaluate the contribution of land cover on local cooling and warming. This sensor network reveals significant village UHIs in all 3 climate zones, with seasonal maximum intensities decreasing from north (1.4°C) to south (0.9°C). During summer, urban warming is most emphasized in minimum temperatures in boreal Haparanda and temperate Geisenheim but weakest in Mediterranean Cazorla, presumably because of limited plant transpiration due to high insolation and drought stress. Urban warming is correlated with building density in all 3 settlements and shows little seasonal variation. Even though the mountain river passing Cazorla substantially cools ambient temperatures at distances <100 m, mitigation of warming through water bodies is limited in the Central and Northern European sites. Our results suggest to treat rural instrumental station data with care and to avoid using data recorded in villages as unbiased reference records to adjust measurements from larger cities.
24.	Linderholm, Hans W., 1968, et al. (författare) Early nineteenth century drought in east central Sweden inferred from dendrochronological and historical archives 2005 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 29:1, s. 63-72 Tidskriftsartikel (refereegranskat)abstract Scots pine tree-ring width data and entries from a farmer's diary were combined to assess early nineteenth century drought in east central Sweden. Tree-ring data were used to reconstruct drought, in the form of the standardized precipitation index (SPI), back to 1750. Daily weather observations in the farmer's diary were translated to temperature and degree of drought for each growing season from 1815 to 1833. During this period, Scots pine growth was constantly below average, and radial growth in 89% of the years between 1806 and 1832 indicated dry summers. Within the same period, severe drought was reported in the diary during several years. Although individual summers have been drier before and after this period, the record suggests that 1806 to 1835 was the longest continuous drought in the last 250 yr, possibly even the last 300 yr. Furthermore, this event seems to have been of regional extent, as indicated by meteorological, historical and tree-ring data from northern and central Europe. The present study showed that a combination of dendrochronological and historical records yields more useful information about past droughts, in terms of impact and long-term context, than one or the other of these sources can provide alone.
25.	Liu, W. B., et al. (författare) Projecting streamflow in the Tangwang River basin (China) using a rainfall generator and two hydrological models 2015 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 62:2, s. 79-97 Tidskriftsartikel (refereegranskat)abstract To estimate the impacts of future climate change on streamflow in the Tangwang River basin (TRB) in northeastern China, 2 hydrological models, the Soil and Water Assessment Tool and the Hydro-Informatic Modeling System, were used. These models are driven by future (2021-2050) local rainfall and temperature scenarios downscaled from global climate model (GCM) simulations from the fifth phase of the Coupled Model Intercomparison Project under 2 emission scenarios (Representative Concentration Pathway [RCP] 4.5 and RCP8.5). The downscaling of rainfall is done with the help of a multisite stochastic rainfall generator (MSRG), which extends the 'Richardson type' rainfall generator to a multisite approach using a modified series-independent and spatial-correlated random numbers method by linking its 4 parameters to large-scale circulations using least-squares regressions. An independent validation of the MSRG shows that it successfully preserves the major daily rainfall characteristics for wet and dry seasons. Relative to the reference period (1971-2000), the annual and wet season (April to October) streamflow during the future period (2021-2050) would decrease overall, which indicates that water resources and the potential flood risk would decline in the TRB. The slightly increased dry season (November to March) streamflow would, to some extent, contribute to the 'spring drought' over this region. Although rainfall is projected to remain un changed in the wet season and the whole year, the increased total evapotranspiration due to the increase in temperature would lead to a decline in total streamflow for this basin. The projected streamflow changes from multiple GCMs in this paper could provide a glimpse into a very plausible future for the water resource management community, and would hence provide valuable references for the sustainable management of water and forest ecosystems under a changing climate.
26.	Meier, Markus, et al. (författare) Climate-related changes in marine ecosystems simulated with a 3-dimensional coupled physical-biogeochemical model of the Baltic Sea 2011 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 48:1, s. 31-55 Tidskriftsartikel (refereegranskat)abstract The combined effect of changing climate and changing nutrient loads from land due to altered land use, sewage water treatment and emissions was studied using a 3-dimensional high-resolution coupled physical-biogeochemical model for the Baltic Sea. Results suggest that global warming causes increased water temperatures and reduced sea ice cover, combined (eventually) with increased winter mean wind speeds and increased river runoff. The projected hydrographic changes could therefore have significant effects on the marine ecosystem. These changes may compete with nutrient load reductions-presently under discussion-that aim to improve the ecological status of the Baltic Sea. Targets that may be sufficient in the present climate might fail under future climate conditions. Using the model, we investigated 4 climate change scenarios and 3 nutrient load scenarios, ranging from a pessimistic 'business as usual' to the 'most optimistic' case (including the Baltic Sea Action Plan, BSAP). In addition, using cause-and-effect studies, we analyzed changing simulated nutrient cycles, oxygen concentrations, and phytoplankton concentrations. As model results for the northern part of the Baltic (Bothnian Bay and Bothnian Sea) are not reliable, we focus the analysis on the Baltic proper, including the Arkona, Bornholm and Gotland basins. The degree of nutrient reduction in nutrient-load reduction scenarios is likely to differ under a future climate, but actions of the BSAP will reduce phytoplankton concentrations also in the future climate. However, the sensitivity of non-linear responses to climate change depends on processes that are not well understood, with current understanding limited by modelling uncertainties (e.g. in the long-term functioning of Baltic Sea sediments as sources and sinks of nutrients).
27.	Melsom, A., et al. (författare) Exploring drift simulations from ocean circulation experiments: application to cod eggs and larval drift 2022 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 86, s. 145-162 Tidskriftsartikel (refereegranskat)abstract Drift models are commonly used to study the transport of early life stages of fish and other marine organisms. Various approaches may be applied to examine the distribution and variability of ocean trajectory pathways. In the present study, we compare results using passive Eulerian tracers and Lagrangian float trajectories that are embedded in numerical models. We supplement this analysis by applying an offline model for drift computations. The contrasts in the results from the various configurations are mainly due to differences in drift depth. Simulations were performed using horizontal resolutions of 4 and 0.8 km. The higher-resolution experiment gives somewhat more realistic results for the drift time from Lofoten to the Tromsoflaket bank at the southwestern entrance of the Barents Sea. Furthermore, differences in results between simulation years are much larger than the differences that arise from the choice of model configuration. Climate variability at high latitudes on a multi-decadal time scale is dominated by large interannual variability superimposed on an underlying moderate warming trend. We conclude that a properly configured offline drift model using hourly or 2-hourly results from a simulation with a horizontal resolution of 1 km or finer is the best approach for investigations of trajectory pathways. The flexibility of an offline drift model is also highly advantageous in biological contexts, as it easily allows for a variety of ways in which behavioural characteristics can be parameterized, including descriptions that are defined after the ocean circulation simulation has been executed.
28.	Omstedt, Anders, 1949, et al. (författare) Use of Baltic Sea modelling to investigate the water cycle and the heat balance in GCM and regional climate models 2000 Ingår i: Climate Research. - 0936-577X .- 1616-1572. ; 15:2, s. 95-108 Tidskriftsartikel (refereegranskat)abstract Results from the first simulations with the Rossby Centre regional climate atmosphere (RCA) model were used to force 2 versions of process-oriented models of the Baltic Sea-one time-dependent, the other considering the mean state. The purpose was primarily to obtain a first scenario of the future state of the Baltic Sea. In addition, we looked at this exercise as a method to evaluate the consistency of the water cycle and the heat balance produced by atmospheric climate models. The RCA model is a high-resolution atmospheric regional model which is forced with lateral conditions from a global model. A large-scale Baltic drainage basin hydrological model, forced by the RCA model, was used to simulate river runoff. Using RCA model data from the control run we found that that the temperature and ice conditions in the Baltic Sea were reasonably realistic while the salinity field was poorly reproduced. We conclude that the modelling of the water cycle needs considerable improvement. We also conclude that the time for the Baltic Sea to respond to the water cycle is much longer than the integration period so far used with the RCA model. Forcing the ocean models with RCA model data from a future scenario with an enhanced greenhouse effect gives an increased sea-surface temperature and a much reduced extent of ice in the Baltic Sea due to climate warming. Also the salinity is reduced, which implies possible serious effects on the future marine life in the Baltic Sea. The results demonstrate that accurate atmospheric modelling of not only the heat balance but also the water cycle is crucial for Baltic Sea climate simulations.
29.	Pulatov, Bakhtiyor, et al. (författare) Effect of climate change on the potential spread of the Colorado potato beetle in Scandinavia : an ensemble approach 2014 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 62:1, s. 15-24 Tidskriftsartikel (refereegranskat)
30.	Ramula, Satu, et al. (författare) Linking phenological shifts to demographic change 2015 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 63:2, s. 135-144 Forskningsöversikt (refereegranskat)abstract Climate-induced phenological shifts may have serious consequences for organisms and populations, but it is challenging to link such shifts to demographic change. Here, we present an overview of current methodological approaches for studying the demographic consequences of phenological shifts, based on a literature survey of 62 studies on diverse taxa. The majority of these studies (66%) were conducted using an approach that linked phenological shifts to demography through the measurement of vital rates (survival, growth, and fecundity). About 18% of the studies used a population-based approach that linked the phenological shifts to changes in population size, and 16% took a combined approach by considering changes in both vital rates and population size. Birds and mammals were overrepresented in studies of the demographic consequences of phenological shifts, compared to their occurrence in nature, while insects were heavily underrepresented. The effects of phenological shifts often varied according to the particular vital rate under consideration, in many cases even within a single species. In the few studies that examined changes in phenology together with both vital rate and population data, the changes in vital rates did not always predict changes in population size. To better understand the ultimate causes of population-level effects we argue that further study is needed on density-dependent aspects of population dynamics and on the sensitivity of population dynamics to perturbations in vital rates. We encourage re searchers to observe multiple vital rates throughout organisms' life-cycles in order to enable more meaningful examination of the consequences of phenological shifts for population dynamics.
31.	Rummukainen, Markku (författare) Our commitment to climate change is dependent on past, present and future emissions and decisions 2015 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 64:1, s. 7-14 Tidskriftsartikel (refereegranskat)abstract The present day global climate change is fueled by our use of fossil fuels and land use change. The already observed warming and other distinct changes in the climate system stem from these human influences and are ongoing. Due to climate system inertia, a part of the climate system's response to this historical forcing remains to manifest itself, which it will do over time. At the same time, socio-economic forces and trends imply some amount of additional emission and land use change, which compounds our commitment to even more substantial climate change. Cumulative carbon dioxide emissions are the basic determinant of the ultimate amount of anthropogenic climate change. Climate system properties, such as climate sensitivity and the carbon cycle, and also possible initiation of non-linear changes, further shape the amount and nature of the long-term change for any set amount of greenhouse gas emissions. While a changed climate is, in practice, now unavoidable, our commitment to continued climate change can be constrained by reductions of global carbon dioxide emissions, their cessation and/or negative emissions. These alternatives have different implications for the long-term unfolding of these changes, but can all considerably reduce the possibility of very large amounts of change, the need for adaptation and responses to negative impacts.
32.	Rutgersson, Anna, et al. (författare) Net precipitation over the Baltic Sea during present and future climate conditions 2002 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 22, s. 27-39 Tidskriftsartikel (refereegranskat)abstract By using a process-oriented ocean model forced with data from a gridded synoptic database, net precipitation values (precipitation minus evaporation) over the Baltic Sea are obtained. For a range of realistic meteorological forcing the average annual value obtained from an 18 yr (1981-1998) simulation ranges between 1100 and 2500 m3 s-1. The monthly variations are significant with the highest values occurring in early summer and even negative values in late autumn. Ice is an important factor, and the net precipitation is close to zero in the southern basins with no ice. Calculated net precipitation for a 98 yr period (1901-1998) using river runoff and maximum ice extent indicates that the investigated 18 yr period was wetter than the almost 100 yr climate mean. A realistic climate estimate of net precipitation during the 20th century is estimated to be 1500 ± 1000 m3 s-1. The evaluation of 2 present day regional climate simulations indicated high precipitation, low evaporation, and thus excessive net precipitation compared to the climate estimate from this investigation. When simulating the effect of increased greenhouse gases, the change in net precipitation was positive but small due to the compensating effects of increased precipitation and increased evaporation associated with increased temperature and reduced ice.
33.	Rutgersson, Anna, 1971-, et al. (författare) Observed changes and variability of atmospheric parameters in the Baltic Sea region during the last 200 years 2014 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 61:2, s. 177-190 Forskningsöversikt (refereegranskat)abstract The Baltic Sea is located in Northern Europe and exhibits significant climate variability, with influence of air masses from arctic to subtropical origin. By updating and discussing results described in the framework of the BACC project (BALTEX Assessment of Climate Change for the Baltic Sea Basin), this study presents observed changes in atmospheric parameters during the last 200 yr. Circulation patterns show large decadal variability with a northward shift of storm tracks and increased cyclonic activity in recent decades with increased persistence of weather types. However, the wind climate shows no robust long-term trends, and is dominated by pronounced (multi-)decadal variability. Near-surface temperatures show continued warming, in particular during spring and winter; this is stronger over northern regions. Up to this point, no long-term trends are detectable for precipitation, although some regional indications exist for an increased length of precipitation periods, and possibly an increased risk of extreme precipitation events.
34.	Saino, Nicola, et al. (författare) Temperature and rainfall anomalies in Africa predict timing of spring migration in trans-Saharan migratory birds 2007 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 35:1-2, s. 123-134 Tidskriftsartikel (refereegranskat)abstract The long-term advance in the timing of bird spring migration in the Northern Hemisphere is associated with global climate change. The extent to which changes in bird phenology reflect responses to weather conditions in the wintering or breeding areas, or during migration, however, remains to be elucidated. We analyse the relationships between the timing of spring migration of 9 species of trans-Saharan migratory birds across the, Mediterranean, and thermal and precipitation anomalies in the main wintering areas south of the Sahara Desert and in North African stopover areas. Median migration dates were collected on the island of Capri (southern Italy) by standardized mist-netting during 1981 to 2004. High temperatures in sub-Saharan Africa (Sahel and Gulf of Guinea) prior to northward migration (February and March) were associated with advanced migration. Moreover, birds migrated earlier when winter rainfall in North Africa was more abundant. The relationships between relevant meteorological variables and timing of migration were remarkably consistent among species, suggesting a coherent response to the same extrinsic stimuli. All these results were obtained while statistically controlling for the long-term trend towards the earlier timing of spring migration across the Mediterranean that has been documented in previous analyses of the same dataset, a trend that was confirmed by the present analyses. In conclusion, our results suggest that thermal conditions in the wintering quarters, as well as rainfall in North African stopover areas, can influence interannual variation in migration phenology of trans-Saharan migratory birds, although the ecological mechanisms that causally link meteorological conditions to the timing of migration remain a matter of speculation.
35.	Scott, D., et al. (författare) Preferred climates for tourism: case studies from Canada, New Zealand and Sweden. 2008 Ingår i: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 38, s. 61-73 Tidskriftsartikel (refereegranskat)
36.	Seim, Andrea, et al. (författare) Climate sensitivity of a millennium-long pine chronology from Albania 2012 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 51:3, s. 217-228 Tidskriftsartikel (refereegranskat)abstract Considerable progress has been made in assessing European climate variations of the last millennium, but little is known about the Mediterranean region and particularly its eastern part including the Balkan Peninsula. This area, however, will be particularly vulnerable to a predicted temperature increase and precipitation decrease, likely resulting in amplified drought extremes and episodes. Here we present a well-replicated composite tree-ring width chronology of millennial length from Albania, Balkan Peninsula. The Pinus heldreichii Christ dataset contains 302 series from 217 living and dead trees from 3 high-elevation sites, and spans the years 968–2008. Signal strength and growth–climate relationships were investigated using subsets according to location, age class, and growth level, as well as differently detrended chronology versions. Growth comparisons amongst the 3 sites’ chronologies, between age classes and between growth-rate groups reveal an overall strong common signal. Growth–climate relationships over the last 100 yr, however, indicate that tree-ring formation does not depend on one single dominant factor, but rather on various combinations of summer precipitation and temperature resulting in temporally varying drought sensitivity. Our results emphasize a mixed and variable climate signal, corresponding with findings from other P. heldreichii sites across the Balkan Peninsula and Southern Italy.
37.	Shi, Feng, et al. (författare) Multi-proxy reconstruction of Arctic summer temperatures over the past 1400 years 2012 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 54:2, s. 113-128 Tidskriftsartikel (refereegranskat)abstract A new multi-proxy summer (June–August) temperature reconstruction for the Arctic region (60°N–90°N) with annual resolution over the past 1400 years is presented. The reconstruction is performed using a novel ensemble method, Ensemble-LOC, designed to preserve low-frequency variability and minimize the influence of the “spurious correlation” between the proxy and instrumental data. The reconstruction is based on a set of 22 proxy records with annual resolution. We find clear evidences for a cold anomaly c. AD 630–770 related to the Dark Age Cold Period, a warm anomaly c. 950–1050 related to the Medieval Climate Anomaly, and a cold anomaly c. AD 1200–1900 related to the Little Ice Age. The strong 20th century warming is also evident. There are three different and distinct warm periods occurring during the Little Ice Age: AD 1470–1510, AD 1550–1570, and AD 1750–1770. However, about half of the total input proxies are not used in the large majority of the reconstructions. We still need additional proxy records from the Arctic region with annual resolution and a strong response to local temperature to further verify the results of this study and in order to investigate possible spatial patterns of past Arctic temperature variability.
38.	Shi, Y., et al. (författare) Effects of climate change on heating and cooling degree days and potential energy demand in the household sector of China 2016 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 67:2, s. 135-149 Tidskriftsartikel (refereegranskat)abstract Future changes of heating and cooling degree days (HDD and CDD) in the 21st century over mainland China are projected with a regional climate model to investigate the potential effects of climate change on energy demand in the household sector. Validation of the model shows a good performance in reproducing the spatial distribution, magnitude and interannual variability of the present day HDD and CDD. Significant decreases in HDD and increases in CDD are projected under the warming. These are further weighted by population projections for a first-order assessment of future changes in energy demand. A larger decrease in population-weighted regional mean HDD compared to the increase in CDD is projected, indicating a decrease of about 15% in potential energy demand for different periods and scenarios in the future. In addition, the simulations show a marked spatial heterogeneity in the change in energy demand. Specifically, we find increases in both heating and cooling demand in parts of northern China due to the increased population there, an increase in cooling demand in the south and decreases in heating demand in the northernmost and western regions. Furthermore, a seasonal shift occurs, with increasing demand in summer and a decrease in winter. Finally, when the future reference temperatures for household heating and cooling change from standards currently used in China to values closer to those in Europe and the USA, potentially large increases in energy demand (~80%) are expected, illustrating the importance of policy decisions concerning household heating and cooling.
39.	Sosa, Carmen, et al. (författare) Effect of weather data aggregation on regional crop simulation for different crops, production conditions, and response variables 2015 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 65, s. 141-157 Tidskriftsartikel (refereegranskat)abstract We assessed the weather data aggregation effect (DAE) on the simulation of cropping systems for different crops, response variables, and production conditions. Using 13 process-based crop models and the ensemble mean, we simulated 30 yr continuous cropping systems for 2 crops (winter wheat and silage maize) under 3 production conditions for the state of North Rhine-Westphalia, Germany. The DAE was evaluated for 5 weather data resolutions (i.e. 1, 10, 25, 50, and 100 km) for 3 response variables including yield, growing season evapotranspiration, and water use efficiency. Five metrics, viz. the spatial bias (Delta), average absolute deviation (AAD), relative AAD, root mean squared error (RMSE), and relative RMSE, were used to evaluate the DAE on both the input weather data and simulated results. For weather data, we found that data aggregation narrowed the spatial variability but widened the., especially across mountainous areas. The DAE on loss of spatial heterogeneity and hotspots was stronger than on the average changes over the region. The DAE increased when coarsening the spatial resolution of the input weather data. The DAE varied considerably across different models, but changed only slightly for different production conditions and crops. We conclude that if spatially detailed information is essential for local management decision, higher resolution is desirable to adequately capture the spatial variability for heterogeneous regions. The required resolution depends on the choice of the model as well as the environmental condition of the study area.
40.	Sosa, Carmen, et al. (författare) Variability of effects of spatial climate data aggregation on regional yield simulation by crop models 2015 Ingår i: Climate Research. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 65, s. 53-69 Tidskriftsartikel (refereegranskat)abstract Field-scale crop models are often applied at spatial resolutions coarser than that of the arable field. However, little is known about the response of the models to spatially aggregated climate input data and why these responses can differ across models. Depending on the model, regional yield estimates from large-scale simulations may be biased, compared to simulations with high-resolution input data. We evaluated this so-called aggregation effect for 13 crop models for the region of North Rhine-Westphalia in Germany. The models were supplied with climate data of 1 km resolution and spatial aggregates of up to 100 km resolution raster. The models were used with 2 crops (winter wheat and silage maize) and 3 production situations (potential, water-limited and nitrogen-water-limited growth) to improve the understanding of errors in model simulations related to data aggregation and possible interactions with the model structure. The most important climate variables identified in determining the model-specific input data aggregation on simulated yields were mainly related to changes in radiation (wheat) and temperature (maize). Additionally, aggregation effects were systematic, regardless of the extent of the effect. Climate input data aggregation changed the mean simulated regional yield by up to 0.2 t ha(-1), whereas simulated yields from single years and models differed considerably, depending on the data aggregation. This implies that large-scale crop yield simulations are robust against climate data aggregation. However, large-scale simulations can be systematically biased when being evaluated at higher temporal or spatial resolution depending on the model and its parameterization.
41.	Syed, F. S., et al. (författare) Inter-annual variability of moisture transport over the northern Indian Ocean and South Asian summer monsoon 2018 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 75:1, s. 23-31 Tidskriftsartikel (refereegranskat)abstract We studied the inter-annual variability of the vertically integrated zonal/meridional moisture transport in the lower troposphere over the northern Indian Ocean using observed data from 1971-2016 for the South Asian summermon soon (SASM) season. The moisture transport variability was dominated by the zonal component associated with the Somali low level jet. For identification of the dominant modes of inter-annual variability, 3-dimensional empirical ortho gonal function analysis was performed. The leading mode, associated with suppressed meridional moisture transport in both the Arabian Sea and Bay of Bengal and increased zonal moisture transport over the Bay of Bengal, was linked with the positive phase of the Indian Ocean dipole and El Nino conditions in the Pacific Ocean. The second leading mode was associated with the enhanced zonal moisture flow over the Arabian Sea extending up to the Bay of Bengal allied with the Somali low level jet, and enhanced northeastward moisture transport over the whole region. This enhanced moisture flow results in stronger monsoon circulation and increased rainfall over South Asia.
42.	Tejedo, Miguel, et al. (författare) Contrasting effects of environmental factors during larval stage on morphological plasticity in post-metamorphic frogs 2010 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 43:1-2, s. 31-39 Tidskriftsartikel (refereegranskat)abstract In organisms with complex life cycles, environmentally induced plasticity across sequential stages can have important consequences on morphology and life history traits such as developmental and growth rates. However, previous research in amphibians and other ectothermic vertebrates suggests that some morphological traits are generally insensitive to environmental inductions. We conducted a literature survey to examine the allometric responses in relative hind leg length and head shape of post-metamorphic anuran amphibians to induced environmental (temperature, resource level, predation and desiccation risk) variation operating during the larval phase in 44 studies using 19 species. To estimate and compare plastic responses across studies, we employed both an index of plasticity and effect sizes from a meta-analysis. We found contrasting trait responses to different environmental cues. Higher temperatures increased development more than growth rate and induced smaller heads but not overall shifts in hind leg length. In contrast, an increment in resource availability increased growth more than development, with a parallel increase in hind leg length but no change in head shape. Increases in predation risk decreased both development and growth rates and slightly reduced relative hind leg length, but there was no change in head shape. Pond desiccation induced quick development and low growth rates, with no changes in morphology. Across environments, both hind leg and head shape plasticity were positively correlated with growth rate plasticity. However, plasticity of developmental rate was only correlated with head shape plasticity. Overall, these results suggest that environmental trends predicted by global warming projections, such as increasing pond temperature and accelerating pond desiccation, will significantly influence hind leg and head morphology in metamorphic frogs, which may affect performance and, ultimately, fitness.
43.	Trnka, Miroslav, et al. (författare) Priority questions in multidisciplinary drought research 2018 Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 75, s. 241-260 Tidskriftsartikel (refereegranskat)abstract Addressing timely and relevant questions across amultitude of spatio-temporal scales,state-of-the-art interdisciplinary drought research will likely increase in importance under projectedclimate change. Given the complexity of the various direct and indirect causes and consequences of adrier world, scientific tasks need to be coordinated efficiently. Drought-related research endeavorsranging from individual projects to global initiatives therefore require prioritization. Here, wepresent 60 priority questions for optimizing future drought research. This topical catalogue reflectsthe experience of 65 scholars from 21 countries and almost 20 fields of research in both naturalsciences and the humanities. The set of drought-related questions primarily covers drought monitoring,impacts, forecasting, climatology, adaptation, as well as planning and policy. The questionshighlight the increasingly important role of remote sensing techniques in drought monitoring, importanceof drought forecasting and understanding the relationships between drought parametersand drought impacts, but also challenges of drought adaptation and preparedness policies.
44.	Um, MJ, et al. (författare) Projected variations in the regional clustering of precipitation stations around Chicago 2016 Ingår i: CLIMATE RESEARCH. - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 67:2, s. 151-163 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
45.	Winsor, P., et al. (författare) Baltic Sea ocean climate: An analysis of 100 yr of hydrographic data with focus on the freshwater budget 2001 Ingår i: Climate Research. - 0936-577X .- 1616-1572. ; 18:1-2, s. 5-15 Tidskriftsartikel (refereegranskat)abstract The Baltic Sea climate is analysed based upon long-term oceanographic measurements. The objective of the work is to study the natural variability of present day climate with focus on the freshwater budget. The results are designed to be used for validation of climate models and for discrimination of the significance of modelled climate change scenarios. Almost 100 yr of observations are used in the study, including data for river runoff, water exchange through the Danish Straits (as calculated from river runoff and from sea level data from the Kattegat), salinity data from the Baltic Sea and the Kattegat, and oxygen content in the deep Baltic Sea. The analyses illustrate that freshwater supply to the Baltic shows large variations on time scales up to several decades. The long-term variations in freshwater storage are closely correlated to accumulated changes in river runoff. This indicates strong positive feedback between the amount of outflowing surface water from the Baltic Sea and the salinity of the inflowing Kattegat water. One implication of the study is that climate control simulations must cover several decades, probably up to 100 yr in order to capture the natural variability of present day climate. Also, models designed to study climate change for the Baltic Sea probably need to start integrating from the present day.
46.	Bärring, Lars, et al. (författare) Defining dry/wet spells for point observations, observed area averages, and regional climate model gridboxes in Europe 2006 Ingår i: Climate Research. - 1616-1572. ; 31:1, s. 35-49 Tidskriftsartikel (refereegranskat)abstract A new method for optimising threshold values of dry/wet spells is evaluated. A set of indices is used to find the best threshold giving good correspondence between the frequency of dry/wet spells in Hadley Centre regional model (HadRM3) output, reference observations with predetermined thresholds, and area-averaged observations. The analyses focus on selected model gridboxes in 3 different European climate regimes (Sweden, UK, Italy), where station data are available from several locations. In addition, a pan-European analysis using the European Climate Assessment (ECA) dataset is carried out. Generally, there is good agreement between point observations and the corresponding area average using the common thresholds of 0.1 or 1.0 mm with observational data. Applying the optimal thresholds on the model output is important, as it typically results in substantially better agreement between the simulated and observed series of dry/wet days. The fitted optimal pan-European dry/wet threshold is (1) 0.47 or 0.15 mm, depending on model version, for the observed point data threshold of 0.1 mm, and (2) 1.2 or 0.56 mm, depending on model version, for the threshold of 1.0 mm.
47.	Gustafsson, Bo, 1966 (författare) Sensitivity of Baltic Sea salinity to large perturbations in climate 2004 Ingår i: Climate Research. - 0936-577X. ; 27:3, s. 237-251 Tidskriftsartikel (refereegranskat)abstract Potential future changes in the salinity of the Baltic Sea must be included in safety assessments of nuclear waste repositories. The salinity affects the potential recipient ecosystems water turnover along the coast, as well as the groundwater hydrology, and groundwater chemistry The time-scales of nuclear waste repositories are extremely long, and climate forecasts must therefore encompass extreme variations. This study presents a model that enables computation of Baltic Sea salinity for different sea level positions and freshwater supplies, thus making it possible to assess the impact of a given climatic change. A modest rise in global sea level (+ 1 m) would le,id to a salinity increase from 8 to 9 in the southern Baltic Proper. An increase in the freshwater supply by about 2000 m(3) s(-1) (approximately +10%) would result in a similar salinity change. Further. a sea level drop of about 5 m or an increase in the freshwater supply by a factor of 3 would reduce the salinity in the southern Baltic Proper to <1, i.e. large parts of the Baltic would become limnic. A 50% decrease in freshwater supply would double the salinity in the southern Baltic Proper to about 15; the effect is more pronounced in the Bothnian Sea and Bothnian Bay, where the salinity would increase from 6 to 13 and from 3.5 to 10, respectively.
48.	Holmer, Björn, 1943 (författare) Fluctuations of winter wheat yields in relation to length of winter in Sweden 1866 to 2006 2008 Ingår i: Climate Research. - 1616-1572. ; 36:3, s. 241-252 Tidskriftsartikel (refereegranskat)
49.	Omstedt, Anders, 1949, et al. (författare) Baltic Sea climate: 200 yr of data on air temperature, sea level variation, ice cover, and atmospheric circulation 2004 Ingår i: Climate Research. - 0936-577X. ; 25:3, s. 205-216 Tidskriftsartikel (refereegranskat)abstract Relevant observed time series for the Baltic Sea region from the last 2 centuries were used to investigate climate variations and trends. These time series were: Stockholm air temperature and magnitude of seasonal temperature cycle, Stockholm sea level data, Baltic Sea maximum ice cover, and circulation types based on regional air pressure data. The definition of climate was analysed by considering how each parameter varies with the time scale. We found that 90 % of the variance was for time scales shorter than 15 yr, the period then used as the climate-averaging time for all studied parameters. The results indicate positive trends for air temperature, sea level, and frequencies of anti-cyclonic circulation and westerly wind types over the last 200 yr. Negative trends were found for the magnitude of seasonal temperature cycle, sea-ice cover, and frequency of southwesterly wind. The major climate changes of the late 19 th century were probably associated with the end of the 'Little Ice Age' and characterized by an unusual high frequency of cyclonic circulation. In the 20 th century, pronounced positive trends were observed in sea level variation and anti-cyclonic circulation. In the most recent studied climate period (1985-2000), air temperature and sea level climate anomalies were positive and lay outside the range of last 200 yr normal variations. The study indicates that increased frequencies of anti-cyclonic circulation and westerly winds have resulted in a slightly warmer climate with reduced seasonal amplitude and reduced ice cover. Thereby, we support the hypothesis that the long-term climate change in the Baltic Sea region is at least partly related to changes in the atmospheric circulation.
50.	Schlyter, P, et al. (författare) Assessment of the impacts of climate change and weather extremes on boreal forests in northern Europe, focusing on Norway spruce 2006 Ingår i: Climate Research. - 1616-1572. ; 31:1, s. 75-84 Tidskriftsartikel (refereegranskat)abstract The boreal and boreo-nemoral forests in Europe, which occur in northern and northeastern Europe, are dominated by 2 coniferous species, Norway spruce Picea abies (L.) Karst. being economically the most important one. Forestry is of major economic importance in this region. Forestry planning and climate change scenarios are based on similar (long-term) timescales, i.e. between 70 and 120 yr. Within the EU project 'Modelling the Impact of Climate Extremes' (MICE), we have used 'present day' runs (1961-1990) and future scenarios (2070-2100, emission scenarios A2 and B2 from the Special Report on Emissions Scenarios [SRES]) of the HadRM3 regional climate model to study and model direct and indirect effects of changing climate on Norway spruce in Sweden and northern Europe. According to our results, extreme climate events like spring temperature backlashes and summer drought will increase in frequency and duration. In combination with a raised mean temperature, climate extremes will negatively precondition trees (i.e. increase their susceptibility) to secondary damage through pests and pathogens. Decreased forest vitality also makes stands more susceptible to windthrow. Storm damage is discussed based on a 100 yr storm damage record for Sweden. Marginally increased frequencies and windspeeds of storms may cause disproportionate increases in windthrow. Increased economic hazards can be expected from a combination of the increased volumes of wind-thrown timber, and a greater likelihood of additional generations of spruce bark beetle Ips typographus (further encouraged by the increase in fallen timber), as a result of a changing climate with warmer summers.

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