SwePub - search: WFRF:(Linderson Maj Lena)

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1.	Achberger, C, et al. (author) Performance of the Rossby Centre regional atmospheric model in Southern Sweden: comparison of simulated and observed precipitation 2003 In: Theoretical and Applied Climatology. - : Springer Science and Business Media LLC. - 1434-4483 .- 0177-798X. ; 76:3-4, s. 219-234 Journal article (peer-reviewed)abstract Two climate model simulations made with the Rossby Centre regional Atmospheric model version I (RCA1) are evaluated for the precipitation climate in Scania, southern-most Sweden. These simulations are driven by the HadCM2 and the ECHAM4/OPYC3 global circulation models (GCMs) for 10 years. Output from the global and the regional simulations are compared with an observational data set, constructed from a dense precipitation gauge network in Scania. Area-averaged time series corresponding to the size and location of the RCA1 grid points in Scania have been created (the Scanian Data Set). This data set was compared to a commonly used gridded surface climatology provided by the Climatic Research Unit (CRU). Relatively large differences were found, mainly due to the fact that the CRU-climatology uses fewer stations and lacks a correction for rain-gauge under-catch. This underlines the importance of the data set chosen for model evaluations. The validation is carried out at a large scale including the whole area of Scania and at the finest resolution of RCA1 (the grid point level). When integrated over the whole area of Scania, RCA1 improves the shape of the annual precipitation cycle and the inter-annual variability compared to output from the GCMs. The RCA1 control climate is generally too wet compared to the observations. At the grid point level, RCA1 improves the simulation of the variability compared to the GCMs. There is a strong positive correlation between precipitation and altitude in all seasons in the observations. This relationship is, however, much weaker and even reversed in the RCA1 simulations. Analysis of the dense rain gauge network reveals features of spatial variability at around 20-35 km in the area and indicates that a finer resolution is needed if the spatial variability in the area is to be better captured by RCA1.
2.	Akerman, H. Jonas, et al. (author) En "ny fjäril" 2023 In: Det nya Svalbard. - 0044-0477. ; , s. 98-113 Book chapter (other academic/artistic)
3.	Bergkvist, John, et al. (author) Modelling managed forest ecosystems in Sweden : An evaluation from the stand to the regional scale 2023 In: Ecological Modelling. - : Elsevier BV. - 0304-3800. ; 477 Journal article (peer-reviewed)abstract Incorporation of a forest management module in the dynamic vegetation model LPJ-GUESS has allowed the study and predictions of management treatment effects on the carbon cycle and on forest ecosystem structure. In this study, LPJ-GUESS is evaluated at the regional scale against observational data from the Swedish National Forest Inventory. Simulated standing volume is compared against observations for the four most common forest types in the country. Furthermore, eddy-covariance flux measurements from the Integrated Carbon Observation System (ICOS) are used to evaluate model predictions of net ecosystem exchange (NEE), gross primary productivity (GPP) and ecosystem respiration (Reco) at the site scale. The model results suggest an adequate representation of standing volume in monocultures of Norway spruce and Scots pine for regional simulations in southern and central Sweden, after an updated parameterization of the species. For northern Sweden, the standing volume in Norway spruce monocultures was overestimated with the updated parameter values. At the stand scale, the model produced mixed results for carbon fluxes when evaluated against eddy-covariance data for two sites, one in central and one in southern Sweden. The interannual variation of GPP was well captured for the central Swedish site, but the modelled average GPP for the period 2015–2019 was overestimated by 9%. For the southern Swedish site, GPP was underestimated by 15% for the corresponding period and the simulated interannual variation was half of the observed. The seasonal estimates of modelled net ecosystem exchange (NEE) deviated from observations and the simulated standing volume was underestimated by 25% for both sites. The results highlight further potential to perform species-specific calibration to capture latitudinal gradients in key ecosystem properties, and to incorporate additional characteristics of site quality which could benefit model accuracy at the scale of individual forest stands, both regarding simulated carbon fluxes and forest stand variables.
4.	Bergkvist, John, et al. (author) Modelling managed forest ecosystems in Sweden : Poster presentation 2022 Conference paper (other academic/artistic)abstract In this work, the forestry-enabled dynamic vegetation model LPJ-GUESS was used to simulate forest standing volume for the three main regions of Sweden. At the regional scale, the model results were evaluated against observational data from the Swedish National Forest Inventory. Carbon fluxes of net ecosystem exchange (NEE), gross primary productivity (GPP), and ecosystem respiration (Reco) were simulated at the local scale on a daily time step for two sites in Sweden and results were evaluated against data from the Integrated Carbon Observation System (ICOS). The model produced adequate results of standing volume in monocultures of Norway spruce and Scots pine for southern and central Sweden, after an updated parameterization of the species. Stand-scale simulations of carbon fluxes produced mixed results after an evaluation against EC data from ICOS.
5.	Bärring, Lars, et al. (author) Defining dry/wet spells for point observations, observed area averages, and regional climate model gridboxes in Europe 2006 In: Climate Research. - 1616-1572. ; 31:1, s. 35-49 Journal article (peer-reviewed)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.
6.	Heiskanen, Jouni, et al. (author) The Integrated Carbon Observation System in Europe 2022 In: Bulletin of the American Meteorological Society. - 0003-0007. ; 103:3, s. 855-872 Journal article (peer-reviewed)abstract Since 1750, land-use change and fossil fuel combustion has led to a 46% increase in the atmospheric carbon dioxide (CO2) concentrations, causing global warming with substantial societal consequences. The Paris Agreement aims to limit global temperature increases to well below 2C above preindustrial levels. Increasing levels of CO2 and other greenhouse gases (GHGs), such as methane (CH4) and nitrous oxide (N2O), in the atmosphere are the primary cause of climate change. Approximately half of the carbon emissions to the atmosphere are sequestered by ocean and land sinks, leading to ocean acidification but also slowing the rate of global warming. However, there are significant uncertainties in the future global warming scenarios due to uncertainties in the size, nature, and stability of these sinks. Quantifying and monitoring the size and timing of natural sinks and the impact of climate change on ecosystems are important information to guide policy-makers' decisions and strategies on reductions in emissions. Continuous, long-term observations are required to quantify GHG emissions, sinks, and their impacts on Earth systems. The Integrated Carbon Observation System (ICOS) was designed as the European in situ observation and information system to support science and society in their efforts to mitigate climate change. It provides standardized and open data currently from over 140 measurement stations across 12 European countries. The stations observe GHG concentrations in the atmosphere and carbon and GHG fluxes between the atmosphere, land surface, and the oceans. This article describes how ICOS fulfills its mission to harmonize these observations, ensure the related long-term financial commitments, provide easy access to well-documented and reproducible high-quality data and related protocols and tools for scientific studies, and deliver information and GHG-related products to stakeholders in society and policy.
7.	Isaksson, Mats, 1961, et al. (author) Calculations of the deposition of 137Cs from nuclear bomb tests and from the Chernobyl accident over the province of Skane in the southern part of Sweden based on precipitation 2000 In: Journal of Environmental Radioactivity. - 0265-931X .- 1879-1700. ; 49, s. 97-112 Journal article (peer-reviewed)abstract The deposition of 137Cs over the province of Skane (an area of about 100x100km2) in the southern part of Sweden has been investigated. The origin of the deposition of 137Cs is, in about equal parts, from nuclear weapons tests and from the Chernobyl nuclear accident and amounts to about 1-3kBq/m2. The activity concentrations of 134Cs and 137Cs in soil samples from 16 sites distributed in a grid pattern over the investigated area have been measured and the depositions from the nuclear weapons tests and from the Chernobyl accident have been separated. These pre- and post-Chernobyl activities have been compared with depositions calculated from measurements of the activity concentrations of 134Cs and 137Cs in precipitation at two places and from measurements of the precipitation from a network of between 113 and 143 precipitation stations. Comparisons with in situ measurements and with aerial survey measurements have also been made. The agreement is good gain and it has been possible to gain a good and detailed knowledge in retrospect of the deposition from measurements of the deposition per mm of precipitation from just a few stations, and of the precipitation from a network of stations. Copyright (C) 2000 Elsevier Science Ltd.
8.	Jönsson, Anna Maria, et al. (author) Climate change and the effect of temperature backlashes causing frost damage in Picea abies 2004 In: Global and Planetary Change. - : Elsevier BV. - 1872-6364 .- 0921-8181. ; 44:1-4, s. 195-207 Journal article (peer-reviewed)abstract In boreal and nemoboreal forests, tree frost hardiness is modified in reaction to cues from day length and temperature. The dehardening processes in Norway spruce, Picea abies, could be estimated to start when the daily mean temperature is above 5 degreesC for 5 days. Bud burst will occur approximately after 120-170 degree-days above 5 degreesC. dependent on genetic differences among provenances. A reduced cold hardiness level during autumn and spring and an advanced onset of bud burst are expected impacts of projected future global wart-ning. The aim of this study was to test if this will increase the risk for frost damage caused by temperature backlashes. This was tested for Sweden by comparing output from the Hadley Centre regional climate model, HadRM3H, for the period 1961-1990 with future IPCC scenario SRES A2 and B2 for 2070-2099. Different indices for calculating the susceptibility to frost damage were used to assess changes in frost damage risk. The indices were based on: (1) the start of dehardening; (2) the severity of the temperature backlash: (3) the timing of bud burst: and (4) the cold hardiness level. The start of dehardening and bud burst were calculated to occur earlier all over the country. which is in line with the overall warming in both climate change scenarios. The frequency of temperature backlashes that may cause frost damage was calculated to increase in the southern part, an effect that became gradually less pronounced towards the north. The different timing of the onset of dehardening mainly caused this systematic latitudinal pattern. In the south, it occurs early in the year when the seasonal temperature progression is slow and large temperature variations occur. In the north, dehardening will occur closer to the spring equinox when the temperature progression is faster. (C) 2004 Elsevier B.V. All rights reserved.
9.	Jönsson, Anna Maria, et al. (author) Modelling as a tool for analysing the temperature-dependent future of the Colorado potato beetle in Europe 2013 In: Global Change Biology. - : Wiley. - 1354-1013. ; 19:4, s. 1043-1055 Journal article (peer-reviewed)abstract A warmer climate may increase the risk of attacks by insect pests on agricultural crops, and questions on how to adapt management practice have created a need for impact models. Phenological models driven by climate data can be used for assessing the potential distribution and voltinism of different insect species, but the quality of the simulations is influenced by a range of uncertainties. In this study, we model the temperature-dependent activity and development of the Colorado potato beetle, and analyse the influence of uncertainty associated with parameterization of temperature and day length response. We found that the developmental threshold has a major impact on the simulated number of generations per year. Little is known about local adaptations and individual variations, but the use of an upper and a lower developmental threshold gave an indication on the potential variation. The day length conditions triggering diapause are known only for a few populations. We used gridded observed temperature data to estimate local adaptations, hypothesizing that cold autumns can leave a footprint in the population genetics by low survival of individuals not reaching the adult stage before winter. Our study indicated that the potential selection pressure caused by climate conditions varies between European regions. Provided that there is enough genetic variation, a local adaption at the northern distribution limit would reduce the number of unsuccessful initiations and thereby increase the potential for spreading to areas currently not infested. The simulations of the impact model were highly sensitive to biases in climate model data, i.e. systematic deviations in comparison with observed weather, highlightening the need of improved performance of regional climate models. Even a moderate temperature increase could change the voltinism of Leptinotarsa decemlineata in Europe, but knowledge on agricultural practice and strategies for countermeasures is needed to evaluate changes in risk of attacks.
10.	Knauer, Jürgen, et al. (author) Towards physiologically meaningful water-use efficiency estimates from eddy covariance data 2018 In: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 24:2, s. 694-710 Journal article (peer-reviewed)abstract Intrinsic water-use efficiency (iWUE) characterizes the physiological control on the simultaneous exchange of water and carbon dioxide in terrestrial ecosystems. Knowledge of iWUE is commonly gained from leaf-level gas exchange measurements, which are inevitably restricted in their spatial and temporal coverage. Flux measurements based on the eddy covariance (EC) technique can overcome these limitations, as they provide continuous and long-term records of carbon and water fluxes at the ecosystem scale. However, vegetation gas exchange parameters derived from EC data are subject to scale-dependent and method-specific uncertainties that compromise their ecophysiological interpretation as well as their comparability among ecosystems and across spatial scales. Here, we use estimates of canopy conductance and gross primary productivity (GPP) derived from EC data to calculate a measure of iWUE (G1, “stomatal slope”) at the ecosystem level at six sites comprising tropical, Mediterranean, temperate, and boreal forests. We assess the following six mechanisms potentially causing discrepancies between leaf and ecosystem-level estimates of G1: (i) non-transpirational water fluxes; (ii) aerodynamic conductance; (iii) meteorological deviations between measurement height and canopy surface; (iv) energy balance non-closure; (v) uncertainties in net ecosystem exchange partitioning; and (vi) physiological within-canopy gradients. Our results demonstrate that an unclosed energy balance caused the largest uncertainties, in particular if it was associated with erroneous latent heat flux estimates. The effect of aerodynamic conductance on G1 was sufficiently captured with a simple representation. G1 was found to be less sensitive to meteorological deviations between canopy surface and measurement height and, given that data are appropriately filtered, to non-transpirational water fluxes. Uncertainties in the derived GPP and physiological within-canopy gradients and their implications for parameter estimates at leaf and ecosystem level are discussed. Our results highlight the importance of adequately considering the sources of uncertainty outlined here when EC-derived water-use efficiency is interpreted in an ecophysiological context.
11.	Lin, Yan-Shih, et al. (author) Optimal stomatal behaviour around the world 2015 In: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 5, s. 459-464 Journal article (peer-reviewed)abstract Stomatal conductance (gs) is a key land-surface attribute as it links transpiration, the dominant component of global land evapotranspiration, and photosynthesis, the driving force of the global carbon cycle. Despite the pivotal role of gs in predictions of global water and carbon cycle changes, a globalscale database and an associated globally applicable model of gs that allow predictions of stomatal behaviour are lacking. Here,we present a database of globally distributed gs obtained in the field for a wide range of plant functional types (PFTs) and biomes. We find that stomatal behaviour differs among PFTs according to their marginal carbon cost of water use, as predicted by the theory underpinning the optimal stomatal model1 and the leaf and wood economics spectrum2,3.We also demonstrate a global relationship with climate. These findings provide a robust theoretical framework for understanding and predicting the behaviour of gs across biomes and across PFTs that can be applied to regional, continental and global-scale modelling of ecosystem productivity, energy balance and ecohydrological processes in a future changing climate.
12.	Lin, Yan-Shih, et al. (author) Optimal stomatal behaviour around the world 2015 In: Nature Climate Change. - 1758-6798 .- 1758-678X. ; 5:5, s. 459-464 Journal article (peer-reviewed)abstract Stomatal conductance (g(s)) is a key land-surface attribute as it links transpiration, the dominant component of global land evapotranspiration, and photosynthesis, the driving force of the global carbon cycle. Despite the pivotal role of g(s) in predictions of global water and carbon cycle changes, a global-scale database and an associated globally applicable model of g(s) that allow predictions of stomatal behaviour are lacking. Here, we present a database of globally distributed g(s) obtained in the field for a wide range of plant functional types (PFTs) and biomes. We find that stomatal behaviour differs among PFTs according to their marginal carbon cost of water use, as predicted by the theory underpinning the optimal stomatal model(1) and the leaf and wood economics spectrum(2,3). We also demonstrate a global relationship with climate. These findin g(s) provide a robust theoretical framework for understanding and predicting the behaviour of g(s) across biomes and across PFTs that can be applied to regional, continental and global-scale modelling of ecosystem productivity, energy balance and ecohydrological processes in a future changing climate.
13.	Linderson, Maj-Lena (author) Objective classification of atmospheric circulation over southern Scandinavia 2001 In: International Journal of Climatology. - : Wiley. - 1097-0088 .- 0899-8418. ; 21:2, s. 155-169 Journal article (peer-reviewed)abstract A method for calculating circulation indices and weather types following the Lamb classification is applied to southern Scandinavia. The main objective is to test the ability of the method to describe the atmospheric circulation over the area, and to evaluate the extent to which the pressure patterns determine local precipitation and temperature in Scania, southernmost Sweden. The weather type classification method works well and produces distinct groups. However, the variability within the group is large with regard to the location of the low pressure centres, which may have implications for the precipitation over the area. The anticyclonic weather type dominates, together with the cyclonic and westerly types. This deviates partly from the general picture for Sweden and may be explained by the southerly location of the study area. The cyclonic type is most frequent in spring, although cloudiness and amount of rain are lowest during this season. This could be explained by the occurrence of weaker cyclones or low air humidity during this time of year. Local temperature and precipitation were modelled by stepwise regression for each season, designating weather types as independent variables. Only the winter season-modelled temperature and precipitation show a high and robust correspondence to the observed temperature and precipitation, even though <60% of the precipitation variance is explained. In the other seasons, the connection between atmospheric circulation and the local temperature and precipitation is low. Other meteorological parameters may need to be taken into account. The time and space resolution of the mean sea level pressure (MSLP) grid may affect the results, as many important features might not be covered by the classification. Local physiography may also influence the local climate in a way that cannot be described by the atmospheric circulation pattern alone, stressing the importance of using more than one observation series.
14.	Linderson, Maj-Lena (author) Spatial distribution of meso-scale precipitation in Scania, southern Sweden 2003 In: Geografiska Annaler. Series A. Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 85:2, s. 183-196 Journal article (peer-reviewed)abstract The aim of this study is to analyse the spatial variability of meso-scale precipitation in Scania and to assess the influence of synoptic scale atmospheric circulation. The modes of spatial variation are revealed by EOF analysis of monthly precipitation totals between 1963 and 1990, which were obtained from a dense rain-gauge network in Scania. southern Sweden. The influence of local physiography on the spatial distribution of precipitation is assessed by GIS techniques using a digital elevation model of Scania. The relation to synoptic scale atmospheric circulation is analysed using regional circulation indices and weather types. It is shown that the daily precipitation distribution in the area is significantly influenced by synoptic scale pressure patterns. Nevertheless. the covariability of the monthly precipitation within Scania is high. About 80% of the precipitation variability is connected to the passage of low-pressure centres over or close to the region. which are likely to produce precipitation over the whole area. A wind-direction dependency found in the distribution indicates that there might be a limit between precipitation regimes within the landscape. Topography greatly influences the spatial distribution in Scania. The distribution of land and surrounding sea is also an important factor and makes the relationship between physiography and precipitation rather complex. The physiographical effects vary over a single year. The dampening effect of the sea on the atmospheric temperature influences the local stability in coastal areas and results in seasonally dependent precipitation patterns.
15.	Linderson, Maj-Lena, et al. (author) Statistical downscaling and scenario construction of precipitation in Scania, southern Sweden 2004 In: Nordic Hydrology. - 0029-1277. ; 35:3, s. 261-278 Journal article (peer-reviewed)abstract Statistical downscaling models for precipitation in Scania, southern Sweden, have been developed and applied to calculate the changes in the future Scanian precipitation climate due to projected changes in the atmospheric composition. The models are based on multiple linear regression, linking large-scale predictors at monthly time resolution to regional statistics of daily precipitation on a monthly basis. To account for spatial precipitation variability within the area, the precipitation statistics were derived for different regions in Scania. The final downscaling models, developed for different regions and seasons, use atmospheric circulation, large-scale humidity and precipitation as predictors. Among the precipitation statistics examined, only the models for estimating the mean precipitation and the frequency of wet days were skilful. Based on the Canadian Global Circulation Model 1 (CGCM1), a future scenario of these two statistics was created. The downscaled scenario shows a significant increase of the annual mean precipitation by about 10% and a slight decrease in the frequency of wet days, indicating an increase in the precipitation amounts as well as in the precipitation intensity. The main increase of precipitation amounts and intensity occur during winter, while the summer precipitation amounts decrease slightly. The seasonal changes found in precipitation are likely attributed to changes in the westerly flow of the atmospheric circulation.
16.	Linderson, Maj-Lena, et al. (author) The effect of water availability on stand-level productivity, transpiration, water use efficiency and radiation use efficiency of field-grown willow clones 2007 In: Biomass & Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 31:7, s. 460-468 Journal article (peer-reviewed)abstract The effect of water availability on stand-level productivity, transpiration, water use efficiency (WUE) and radiation use efficiency (RUE) is evaluated for different willow clones at stand level. The measurements were made during the growing season 2000 in a 3-year-old plantation in Scania, southernmost Sweden. Six willow clones were included in the study: L78183, SW Rapp, SW Jorunn, SW Jorr, SW Tora and SW Loden. All clones were exposed to two water treatments: rain-fed, non-irrigated treatment and reduced water availability by reduced soil water recharge. Field measurements of stem sap-flow and biometry are up-scaled to stand transpiration and stand dry substance production and used to assess WUE. RUE is estimated from the ratio between the stand dry substance production and the accumulated absorbed photosynthetic active radiation over the growing season. The total stand transpiration rate for the 5 months lies between 100 and 325mm, which is fairly low compared to the Penman-Monteith transpiration for willow, reaching 400-450 mm for the same period. Mean WUE of all clones and treatments is 5.3 g/kg, which is high compared to earlier studies, while average RUE is 0.31 g/mol, which is slightly low compared to other results. Generally, all clones, except for Jorunn, seem to be better off concerning biomass production, WUE and RUE than the reference clone. Jorr, Jorunn and Loden also seem to be able to cope with the reduced water availability with increase in the water use efficiency. Tora performs significantly better than the other clones concerning both growth and efficiency in light and water use, but the effect of the dry treatment on stem growth shows sensitivity to water availability. The reduced stem growth could be due to a change in allocation patterns. (C) 2007 Elsevier Ltd. All rights reserved.
17.	Linderson, Maj-Lena (author) The Spatial Distribution of Precipitation in Scania, Southern Sweden. Observations, model simulations and statistical downscaling. 2002 Doctoral thesis (other academic/artistic)abstract This thesis focusses on the spatial distribution of precipitation within Scania and on its relation with large-scale climate. The spatial distribution of Scanian precipitation was analysed using a dense rain-gauge network of daily measurements. The performance of the Rossby Centre regional Atmospheric model in simulating the observed spatial distribution was evaluated. The influence of the regional atmospheric circulation on the observed precipitation distribution was assessed and statistical downscaling models, based on monthly large-scale climate, were established for mean precipitation and frequency of wet-days. The models were used to construct future estimates of these statistics, based on a GCM projection. It was found that the spatial co-variability of the monthly precipitation within Scania is high. Topography is the major factor influencing the precipitation distribution. Furthermore, there is a significant difference between the southeastern and the northwestern part of Scania related to the land/sea distribution in the area. Consequently, the annual mean precipitation in Scania has a spatial variation with a typical length scale of 20-35 km elongated in the N/NW to S/SE direction. The spatial patterns are not well captured by the RCA1 dynamical downscaling model. This may partly be caused by a too coarse resolution (44 km) of the RCA1. In total, 80-90% of the observed monthly meso-scale precipitation variation of Scania can successfully be related to, and explained by, the regional atmospheric circulation indices. This indicates that the regional atmospheric circulation is an important predictor in the statistical downscaling of precipitation. The daily precipitation patterns are also largely influenced by the pressure patterns in regional scale. Daily mean precipitation and the frequency of wet-days could be successfully modelled by the statistical downscaling procedure, using the monthly predictors of large-scale precipitation, relative humidity and atmospheric circulation indices. The downscaled scenario shows a significant increase of the annual daily mean precipitation by about 10 % and a decrease in frequency of wet-days by 1 % between the control (1961-90) climate and the scenario (2041-70) climate. Both daily mean precipitation and frequency of wet-days increase during winter and decrease during summer. The results also indicate an increase in the intensity of the precipitation, especially during winter. A winter increase and summer decrease of the westerly flow seems to be the major cause of the changes.
18.	Linderson, Maj-Lena, et al. (author) Up-scaling of water use efficiency from leaf to canopy as based on leaf gas exchange relationships and the modeled in-canopy light distribution 2012 In: Agricultural and Forest Meteorology. - : Elsevier BV. - 1873-2240 .- 0168-1923. ; 152, s. 201-211 Journal article (peer-reviewed)abstract Abstract in UndeterminedThe aim of this study was to evaluate the extent to which water use efficiency (WUE) at leaf scale can be used to assess WUE at canopy scale, leaf WUE being assumed to be a constant function of vapor pressure deficit and to thus not be dependent upon other environmental factors or varying leaf properties. Leaf WUE and its variability and dependencies were assessed using leaf gas-exchange measurements obtained during two growing seasons, 1999 and 2000, at the Soroe beech forest study site on Zealand in Denmark. It was found that the VPD-normalized leaf VVUE, WUEnormleaf, although dependent on incoming PAR below 500 p,mol m(-2) s(-1) is independent, both of the canopy levels and of variations in the environmental parameters. The average WUEnormleaf for PAR above 500 mu mol m(-2) s(-1) was found to be 5.5 mu mol CO2 (mmol H2O)(-1) hPa and, for the full range, 2.3 mu mol CO2 (mmol H2O)(-1) hPa. These results showed that WUE can be up-scaled from leaf to canopy on the basis of WUEnormleaf and the PAR distribution within the canopy. The up-scaling conducted was based on this WUEnormleaf - PAR relationship, the light distribution being assessed using the MAESTRA model, parameterized in accordance with measurements obtained for the Soroe forest. The up-scaled WUE was then compared with WUE as estimated from turbulent flux data measured above the forest with the eddy-covariance technique. The modeled daily canopy WUE obtained for daytime fluxes (6:00 AM-6:00 PM) was found to be in agreement with corresponding canopy WUE estimates based on the turbulent fluxes observed and to be dependent on VDP and light intensity alone, its thus being independent of other environmental factors. Accordingly, canopy WUE can be estimated on the basis of the up-scaled WUE relationships, provided incident PAR and VPD within the canopy are known.
19.	Lindroth, Anders, et al. (author) Effects of drought and meteorological forcing on carbon and water fluxes in Nordic forests during the dry summer of 2018 2020 In: Philosophical Transactions of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 375:1810 Journal article (peer-reviewed)abstract The Nordic region was subjected to severe drought in 2018 with a particularly long-lasting and large soil water deficit in Denmark, Southern Sweden and Estonia. Here, we analyse the impact of the drought on carbon and water fluxes in 11 forest ecosystems of different composition: spruce, pine, mixed and deciduous. We assess the impact of drought on fluxes by estimating the difference (anomaly) between year 2018 and a reference year without drought. Unexpectedly, the evaporation was only slightly reduced during 2018 compared to the reference year at two sites while it increased or was nearly unchanged at all other sites. This occurred under a 40 to 60% reduction in mean surface conductance and the concurrent increase in evaporative demand due to the warm and dry weather. The anomaly in the net ecosystem productivity (NEP) was 93% explained by a multilinear regression with the anomaly in heterotrophic respiration and the relative precipitation deficit as independent variables. Most of the variation (77%) was explained by the heterotrophic component. Six out of 11 forests reduced their annual NEP with more than 50 g C m(-2)yr(-1)during 2018 as compared to the reference year. The NEP anomaly ranged between -389 and +74 g C m(-2)yr(-1)with a median value of -59 g C m(-2)yr(-1). This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.
20.	Medlyn, Belinda E, et al. (author) How do leaf and ecosystem measures of water-use efficiency compare? 2017 In: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 216:3, s. 758-770 Journal article (peer-reviewed)abstract The terrestrial carbon and water cycles are intimately linked: the carbon cycle is driven by photosynthesis, while the water balance is dominated by transpiration, and both fluxes are controlled by plant stomatal conductance. The ratio between these fluxes, the plant water-use efficiency (WUE), is a useful indicator of vegetation function. WUE can be estimated using several techniques, including leaf gas exchange, stable isotope discrimination, and eddy covariance. Here we compare global compilations of data for each of these three techniques. We show that patterns of variation in WUE across plant functional types (PFTs) are not consistent among the three datasets. Key discrepancies include the following: leaf-scale data indicate differences between needleleaf and broadleaf forests, but ecosystem-scale data do not; leaf-scale data indicate differences between C3 and C4 species, whereas at ecosystem scale there is a difference between C3 and C4 crops but not grasslands; and isotope-based estimates of WUE are higher than estimates based on gas exchange for most PFTs. Our study quantifies the uncertainty associated with different methods of measuring WUE, indicates potential for bias when using WUE measures to parameterize or validate models, and indicates key research directions needed to reconcile alternative measures of WUE.
21.	Olofsson, Jörgen, et al. (author) Educating the next generation decision makers - the multi-disciplinary classroom as a platform for developing communication skills needed for future progress of adaptation measures 2015 Conference paper (peer-reviewed)abstract The scientific knowledge of climate change processes and their worrying future implications for human societies and natural systems has developed considerably during the last decade, but necessary adaptive actions by decision makers have so far been rather limited. There are several causes to this, such as a discrepancy related to the communication between climate scientists and end-users, and the lack of climate educational background of several decision makers. This results in decision makers not fully incorporating knowledge on climate change and impacts into adaptive action measures. Hence, educating future decision makers, as well as scientists providing the climate knowledge, is therefore highly important in order to minimise this reduction of knowledge transfer, and by so improve the necessary decision processes of climate actions. Here we report how the Department of Physical Geography and Ecosystem Sciences, and the Centre for Environmental and Climate Research at Lund University, work on continuously improving climate communication skills of our Masters students. Throughout the academic programs with Masters in Physical Geography and Ecosystem Analysis, and in Climate Strategy, our students have mixed educational background (ranging from meteorologists to geographers, from biologists to engineers as well as political science students) which generates a unique classroom environment for learning communication across borders of different understanding and knowledge background. Here we present interesting outcomes of such a set-up, including work hands-on with issues related to climate change, impacts and adaptation through exercises, seminars and projects. Students learn how to systematically treat background climate information and carefully analyse their results, and to efficiently communicate their findings through written reports and oral presentations. Teachers provide formative constructive feedback on assignments throughout the programs, for students to improve their subject knowledge and understanding as well as their communication performance. To further motivate our students, external professionals from enterprises and authorities working on climate related issues are frequently invited as guest lecturers, which also may act as co-supervisors of degree projects. These networks also contribute to valuable transfer of scientific knowledge between our departments and the non-academia world. Furthermore, teachers are encouraged to develop their own communication skills by e.g. attend tailored pedagogic courses and conferences. Our Master programs provide a highly stimulating learning environment in which students are trained to become effective communicators of climate related knowledge, being able to critically analyse climate information, impact probabilities, and adaptation strategies, and thereby to take on the role as decision makers.
22.	Papale, Dario, et al. (author) Standards and Open Access are the ICOS Pillars Reply to "Comments on 'The Integrated Carbon Observation System in Europe'" 2023 In: Bulletin of the American Meteorological Society. - 0003-0007. ; 104:12, s. 953-955 Journal article (peer-reviewed)abstract In his comment (Kowalski 2023) on our recent publication (Heiskanen et al. 2022) where we present the Integrated Carbon Observation System (ICOS) research infrastructure, Andrew Kowalski introduces three important and, in our opinion, different potential issues in the definition, collection, and availability of field measurements made by the ICOS network, and he proposes possible solutions to these issues.
23.	Poyatos, R., et al. (author) Global transpiration data from sap flow measurements: the SAPFLUXNET database 2021 In: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 13:6, s. 2607-2649 Journal article (peer-reviewed)abstract Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The "sapfluxnetr" R package - designed to access, visualize, and process SAPFLUXNET data - is available from CRAN.
24.	Pulatov, Bakhtiyor, et al. (author) Effect of climate change on the potential spread of the Colorado potato beetle in Scandinavia : an ensemble approach 2014 In: Climate Research. - : Inter-Research Science Center. - 1616-1572 .- 0936-577X. ; 62:1, s. 15-24 Journal article (peer-reviewed)
25.	Pulatov, Bakhtiyor, et al. (author) Evaluation of the phenological synchrony between potato crop and Colorado potato beetle under future climate in Europe 2016 In: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 0167-8809. ; 224, s. 39-49 Journal article (peer-reviewed)abstract Europe is one of the world's largest food producers, and climate change may pose a serious threat to food security in the region. In the present study, we assess the potential impact of climate change on the Colorado Potato Beetle (CPB), Leptinotarsa decemlineata (Say)-a severe pest of potato (Solanum tuberosum, L.). We also investigate the possible impact of climate change on the phenological development of potato. The main focus is on factors that may limit the northward expansion of the CPB, and the number of generations per year in areas where the insect pest is already present. These factors include lack of temperature sum for completed development before winter, and lack of food (i.e. potato) due to mismatches in insect-host plant phenological synchrony.We use a gridded observational dataset and an ensemble of bias corrected regional climate model data for the period of 1981-2099, representing RCP8.5, as input to a potato and CPB phenological model. The results show that in the future, CPB individuals with a low developmental threshold (+10 °C) can complete maturity of two generations per year before potato is harvested in most parts of Europe. A third generation of CPB may not be able to complete maturation due to lack of food in south and central Europe, while temperature becomes a limiting factor further north. In north-eastern Europe, the initiation of a first generation may be delayed due to lack of food in spring. CPBs with a high developmental threshold (+12 °C) will emerge later from winter hibernation, and food availability will therefore not be a problem in spring. However, individuals with a high developmental threshold face a greater risk of regeneration failure caused by harvesting of potato in autumn. The potential lack of food in autumn may also increase the strength of selection towards a low developmental threshold in northern populations. The combined analysis of CPB and potato phenology indicated that climate change can lead to increased pressure from the CPB in most potato growing areas.

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