| 1. |
- Trnka, Miroslav, et al.
(författare)
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Priority questions in multidisciplinary drought research
- 2018
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Ingår i: Climate Research (CR). - : Inter-Research Science Center. - 0936-577X .- 1616-1572. ; 75, s. 241-260
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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.
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| 2. |
- Brázdil, Rudolf, et al.
(författare)
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European climate of the past 500 years: new challenges for historical climatology
- 2010
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Ingår i: Climatic Change. - Netherlands : Springer. - 0165-0009 .- 1573-1480. ; 101:1-2, s. 7-40
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Tidskriftsartikel (refereegranskat)abstract
- Temperature reconstructions from Europe for the past 500 years basedon documentary and instrumental data are analysed. First, the basic documentarydata sources, including information about climate and weather-related extremes, aredescribed. Then, the standard palaeoclimatological reconstruction method adoptedhere is discussed with a particular application to temperature reconstructions fromdocumentary-based proxy data. The focus is on two new reconstructions; January–April mean temperatures for Stockholm (1502–2008), based on a combination ofdata for the sailing season in the Stockholm harbour and instrumental temperaturemeasurements, and monthly Central European temperature (CEuT) series (1500–2007) based on documentary-derived temperature indices of the Czech Republic,Germany and Switzerland combined with instrumental records from the samecountries. The two series, both of which are individually discussed in greater detail in subsequent papers in this special edition, are here compared and analysed usingrunning correlations and wavelet analysis. While the Stockholm series shows apronounced low-frequency component, the CEuT series indicates much weaker lowfrequencyvariations. Both series are analysed with respect to three different longperiodreconstructions of the North Atlantic Oscillation (NAO) and are comparedwith other European temperature reconstructions based on tree-rings, wine-harvestdata and various climate multiproxies. Correlation coefficients between individualproxy-based series show weaker correlations compared to the instrumental data.There are also indications of temporally varying temperature cross-correlationsbetween different areas of Europe. The two temperature reconstructions have alsobeen compared to geographically corresponding temperature output from simulationswith global and regional climate models for the past few centuries. The findingsare twofold: on the one hand, the analysis reinforces the hypothesis that the indexdatabased CEuT reconstruction may not appropriately reflect the centennial scalevariations. On the other hand, it is possible that climate models may underestimateregional decadal variability. By way of a conclusion, the results are discussed froma broader point of view and attention is drawn to some new challenges for futureinvestigations in the historical climatology in Europe.
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| 3. |
- Büntgen, Ulf, et al.
(författare)
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Recent European drought extremes beyond Common Era background variability
- 2021
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Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 14:4, s. 190-196
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Tidskriftsartikel (refereegranskat)abstract
- Europe's recent summer droughts have had devastating ecological and economic consequences, but the severity and cause of these extremes remain unclear. Here we present 27,080 annually resolved and absolutely dated measurements of tree-ring stable carbon and oxygen (delta C-13 and delta O-18) isotopes from 21 living and 126 relict oaks (Quercus spp.) used to reconstruct central European summer hydroclimate from 75 bce to 2018 ce. We find that the combined inverse delta C-13 and delta O-18 values correlate with the June-August Palmer Drought Severity Index from 1901-2018 at 0.73 (P < 0.001). Pluvials around 200, 720 and 1100 ce, and droughts around 40, 590, 950 and 1510 ce and in the twenty-first century, are superimposed on a multi-millennial drying trend. Our reconstruction demonstrates that the sequence of recent European summer droughts since 2015 ce is unprecedented in the past 2,110 years. This hydroclimatic anomaly is probably caused by anthropogenic warming and associated changes in the position of the summer jet stream. European summer droughts in recent years are anomalously severe compared with those of the previous 2,000 years, according to a synthesis of annually resolved tree-ring carbon and oxygen isotope records.
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| 4. |
- Dobrovolný, Petr, et al.
(författare)
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Monthly, seasonal and annual temperature reconstructions for Central Europe derived from documentary evidence and instrumental records since AD 1500
- 2010
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Ingår i: Climatic Change. - Netherlands : Springer. - 0165-0009 .- 1573-1480. ; 101:1-2, s. 69-107
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Tidskriftsartikel (refereegranskat)abstract
- Monthly temperature series for Central Europe back to AD 1500 aredeveloped from documentary index series from Germany, Switzerland and theCzech Republic (1500–1854) and 11 instrumental temperature records (1760–2007).Documentary evidence from the Low Countries, the Carpathian Basin and Polandare used for cross-checking for earlier centuries. The instrumental station recordsare corrected for inhomogeneities, including insufficient radiation protection ofearly thermometers and the urban heat island effect. For overlapping period (1760–1854), the documentary data series correlate with instrumental temperatures, moststrongly in winter (86% explained variance in January) and least in autumn (56%in September). For annual average temperatures, 81% of the variance is explained.Verification statistics indicate high reconstruction skill for most months and seasons.The last 20 years (since 1988) stand out as very likely the warmest 20-year period,accounting for the calibration uncertainty and decreases in proxy data quality beforethe calibration period. The new reconstruction displays a previously unobserved long-term decrease in DJF, MAM and JJA temperature variability over last fivecenturies. Compiled monthly, seasonal and annual series can be used to improve therobustness of gridded large-scale European temperature reconstructions and possibleimpact studies. Further improvement of the reconstruction would be achieved ifdocumentary data from other European countries are further developed.
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| 5. |
- Forzieri, Giovanni, et al.
(författare)
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The Database of European Forest Insect and Disease Disturbances: DEFID2
- 2023
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Ingår i: Global Change Biology. - 1365-2486. ; 29:21, s. 6040-6065
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Tidskriftsartikel (refereegranskat)abstract
- Insect and disease outbreaks in forests are biotic disturbances that can profoundly alter ecosystem dynamics. In many parts of the world, these disturbance regimes are intensifying as the climate changes and shifts the distribution of species and biomes. As a result, key forest ecosystem services, such as carbon sequestration, regulation of water flows, wood production, protection of soils, and the conservation of biodiversity, could be increasingly compromised. Despite the relevance of these detrimental effects, there are currently no spatially detailed databases that record insect and disease disturbances on forests at the pan-European scale. Here, we present the new Database of European Forest Insect and Disease Disturbances (DEFID2). It comprises over 650,000 harmonized georeferenced records, mapped as polygons or points, of insects and disease disturbances that occurred between 1963 and 2021 in European forests. The records currently span eight different countries and were acquired through diverse methods (e.g., ground surveys, remote sensing techniques). The records in DEFID2 are described by a set of qualitative attributes, including severity and patterns of damage symptoms, agents, host tree species, climate-driven trigger factors, silvicultural practices, and eventual sanitary interventions. They are further complemented with a satellite-based quantitative characterization of the affected forest areas based on Landsat Normalized Burn Ratio time series, and damage metrics derived from them using the LandTrendr spectral–temporal segmentation algorithm (including onset, duration, magnitude, and rate of the disturbance), and possible interactions with windthrow and wildfire events. The DEFID2 database is a novel resource for many large-scale applications dealing with biotic disturbances. It offers a unique contribution to design networks of experiments, improve our understanding of ecological processes underlying biotic forest disturbances, monitor their dynamics, and enhance their representation in land-climate models. Further data sharing is encouraged to extend and improve the DEFID2 database continuously. The database is freely available at https://jeodpp.jrc.ec.europa.eu/ftp/jrc-opendata/FOREST/DISTURBANCES/DEFID2/.
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| 6. |
- Luterbacher, Jürg, et al.
(författare)
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Circulation dynamics and its influence on European and Mediterranean January–April climate over the past half millennium : results and insights from instrumental data,documentary evidence and coupled climate models
- 2010
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Ingår i: Climatic Change. - Netherlands : Springer. - 0165-0009 .- 1573-1480. ; 101:1-2, s. 201-234
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Tidskriftsartikel (refereegranskat)abstract
- We use long instrumental temperature series together with available field reconstructions of sea-level pressure (SLP) and three-dimensional climate modelsimulations to analyze relations between temperature anomalies and atmospheric circulation patterns over much of Europe and the Mediterranean for the late winter/early spring (January–April, JFMA) season. A Canonical Correlation Analysis(CCA) investigates interannual to interdecadal covariability between a new gridded SLP field reconstruction and seven long instrumental temperature series covering the past 250 years. We then present and discuss prominent atmospheric circulation patterns related to anomalous warm and cold JFMA conditions within different European areas spanning the period 1760–2007. Next, using a data assimilation technique, we link gridded SLP data with a climate model (EC-Bilt-Clio) for a better dynamical understanding of the relationship between large scale circulationand European climate. We thus present an alternative approach to reconstruct climate for the pre-instrumental period based on the assimilated model simulations.Furthermore, we present an independent method to extend the dynamic circulation analysis for anomalously cold European JFMA conditions back to the sixteenth century. To this end, we use documentary records that are spatially representative for the long instrumental records and derive, through modern analogs, large-scale SLP, surface temperature and precipitation fields. The skill of the analog method is tested in the virtual world of two three-dimensional climate simulations (ECHOGand HadCM3). This endeavor offers new possibilities to both constrain climate model into a reconstruction mode (through the assimilation approach) and to better assess documentary data in a quantitative way.
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| 7. |
- Trachsel, Mathias, et al.
(författare)
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Multi-archive summer temperature reconstruction for the European Alps, AD 1053-1996
- 2012
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Ingår i: Quaternary Science Reviews. - : Elsevier. - 0277-3791 .- 1873-457X. ; 46, s. 66-79
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Tidskriftsartikel (refereegranskat)abstract
- We present a multi-archive, multi-proxy summer temperature reconstruction for the European Alpscovering the period AD 1053-1996 using tree-ring and lake sediment data. The new reconstruction isbased on nine different calibration approaches and errors were estimated conservatively. Summertemperatures of the last millennium are characterised by two warm (AD 1053-1171 and 1823-1996) andtwo cold phases (AD 1172-1379 and 1573-1822). Highest pre-industrial summer temperatures of the12th century were 0.3 degC warmer than the 20th century mean but 0.35 degC colder than proxy derivedtemperatures at the end of the 20th century. The lowest temperatures at the end of the 16th centurywere ~1 degC lower than the 20th century mean.
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| 8. |
- Wetter, Oliver, et al.
(författare)
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The year-long unprecedented European heat and drought of 1540-a worst case
- 2014
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Ingår i: Climatic Change. - : Springer Science and Business Media LLC. - 0165-0009 .- 1573-1480. ; 125:3-4, s. 349-363
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Tidskriftsartikel (refereegranskat)abstract
- The heat waves of 2003 in Western Europe and 2010 in Russia, commonly labelled as rare climatic anomalies outside of previous experience, are often taken as harbingers of more frequent extremes in the global warming-influenced future. However, a recent reconstruction of spring-summer temperatures for WE resulted in the likelihood of significantly higher temperatures in 1540. In order to check the plausibility of this result we investigated the severity of the 1540 drought by putting forward the argument of the known soil desiccation-temperature feedback. Based on more than 300 first-hand documentary weather report sources originating from an area of 2 to 3 million km(2), we show that Europe was affected by an unprecedented 11-month-long Megadrought. The estimated number of precipitation days and precipitation amount for Central and Western Europe in 1540 is significantly lower than the 100-year minima of the instrumental measurement period for spring, summer and autumn. This result is supported by independent documentary evidence about extremely low river flows and Europe-wide wild-, forest- and settlement fires. We found that an event of this severity cannot be simulated by state-of-the-art climate models.
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| 9. |
- Zorita, Eduardo, et al.
(författare)
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European temperature records of the past five centuries based on documentary/instrumental information compared to climate simulations
- 2010
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Ingår i: Climatic Change. - Netherlands : Springer. - 0165-0009 .- 1573-1480. ; 101:1-2, s. 143-168
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Tidskriftsartikel (refereegranskat)abstract
- Two European temperature reconstructions for the past half-millennium,January-to-April air temperature for Stockholm (Sweden) and seasonal temperaturefor a Central European region, both derived from the analysis of documentarysources and long instrumental records, are compared with the output of climate simulations with the model ECHO-G. The analysis is complemented by comparisonswith the long (early)-instrumental record of Central England Temperature(CET). Both approaches to study past climates (simulations and reconstructions)are burdened with uncertainties. The main objective of this comparative analysisis to identify robust features and weaknesses in each method which may help toimprove models and reconstruction methods. The results indicate a general agreementbetween simulations obtained with temporally changing external forcings andthe reconstructed Stockholm and CET records for the multi-centennial temperaturetrend over the recent centuries, which is not reproduced in a control simulation.This trend is likely due to the long-term change in external forcing. Additionally,the Stockholm reconstruction and the CET record also show a clear multi-decadalwarm episode peaking around AD 1730, which is absent in the simulations. Neitherthe reconstruction uncertainties nor the model internal climate variability caneasily explain this difference. Regarding the interannual variability, the Stockholmseries displays, in some periods, higher amplitudes than the simulations but thesedifferences are within the statistical uncertainty and further decrease if output froma regional model driven by the global model is used. The long-term trend of theCentral European temperature series agrees less well with the simulations. Thereconstructed temperature displays, for all seasons, a smaller difference between thepresent climate and past centuries than is seen in the simulations. Possible reasons forthese differences may be related to a limitation of the traditional ‘indexing’ techniquefor converting documentary evidence to temperature values to capture long-termclimate changes, because the documents often reflect temperatures relative to thecontemporary authors’ own perception of what constituted ‘normal’ conditions. Bycontrast, the amplitude of the simulated and reconstructed inter-annual variabilityagrees rather well.
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