94 research outputs found
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Subsampling impact on the climate change signal over poland based on simulations from statistical and dynamical downscaling
Most impact studies using downscaled climate data as input assume that the selection of few global climate models (GCMs) representing the largest spread covers the likely range of future changes. This study shows that including more GCMs can result in a very different behavior. We tested the influence of selecting various subsets of GCMs on the climate change signal over Poland from simulations based on dynamical and empirical-statistical downscaling methods. When the climate variable is well simulated by the GCM, such as temperature, results showed that both downscaling methods agree on a warming over Poland by up to 2° or 5°C assuming intermediate or high emission scenarios, respectively, by 2071-2100. As a less robust simulated signal through GCMs, precipitation is expected to increase by up to 10% by 2071-2100 assuming the intermediate emission scenario. However, these changes are uncertain when the high emission scenario and the end of the twenty-first century are of interest. Further, an additional bootstrap test revealed an underestimation in the warming rate varying from 0.5° to more than 4°C over Poland that was found to be largely influenced by the selection of few driving GCMs instead of considering the full range of possible climate model outlooks. Furthermore, we found that differences between various combinations of small subsets from the GCM ensemble of opportunities can be as large as the climate change signal. © 2019 American Meteorological Society
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CHASE-PL Climate Projection dataset over Poland - Bias adjustment of EURO-CORDEX simulations
The CHASE-PL (Climate change impact assessment for selected sectors in Poland) Climate Projections – Gridded Daily Precipitation and Temperature dataset 5 km (CPLCP-GDPT5) consists of projected daily minimum and maximum air temperatures and precipitation totals of nine EURO-CORDEX regional climate model outputs bias corrected and downscaled to a 5 km  ×  5 km grid. Simulations of one historical period (1971–2000) and two future horizons (2021–2050 and 2071–2100) assuming two representative concentration pathways (RCP4.5 and RCP8.5) were produced. We used the quantile mapping method and corrected any systematic seasonal bias in these simulations before assessing the changes in annual and seasonal means of precipitation and temperature over Poland. Projected changes estimated from the multi-model ensemble mean showed that annual means of temperature are expected to increase steadily by 1 °C until 2021–2050 and by 2 °C until 2071–2100 assuming the RCP4.5 emission scenario. Assuming the RCP8.5 emission scenario, this can reach up to almost 4 °C by 2071–2100. Similarly to temperature, projected changes in regional annual means of precipitation are expected to increase by 6 to 10 % and by 8 to 16 % for the two future horizons and RCPs, respectively. Similarly, individual model simulations also exhibited warmer and wetter conditions on an annual scale, showing an intensification of the magnitude of the change at the end of the 21st century. The same applied for projected changes in seasonal means of temperature showing a higher winter warming rate by up to 0.5 °C compared to the other seasons. However, projected changes in seasonal means of precipitation by the individual models largely differ and are sometimes inconsistent, exhibiting spatial variations which depend on the selected season, location, future horizon, and RCP. The overall range of the 90 % confidence interval predicted by the ensemble of multi-model simulations was found to likely vary between −7 % (projected for summer assuming the RCP4.5 emission scenario) and +40 % (projected for winter assuming the RCP8.5 emission scenario) by the end of the 21st century. Finally, this high-resolution bias-corrected product can serve as a basis for climate change impact and adaptation studies for many sectors over Poland. The CPLCP-GDPT5 dataset is publicly available at https://doi.org/10.4121/uuid:e940ec1a-71a0-449e-bbe3-29217f2ba31d
Effect of Climate Change on Hydrology, Sediment and Nutrient Losses in Two Lowland Catchments in Poland
Future climate change is projected to have significant impact on water resources availability and quality in many parts of the world. The objective of this paper is to assess the effect of projected climate change on water quantity and quality in two lowland catchments (the Upper Narew and the Barycz) in Poland in two future periods (near future: 2021–2050, and far future: 2071– 2100). The hydrological model SWAT was driven by climate forcing data from an ensemble of nine bias-corrected General Circulation Models—Regional Climate Models (GCM-RCM) runs based on the Coordinated Downscaling Experiment—European Domain (EURO-CORDEX). Hydrological response to climate warming and wetter conditions (particularly in winter and spring) in both catchments includes: lower snowmelt, increased percolation and baseflow and higher runoff. Seasonal differences in the response between catchments can be explained by their properties (e.g., different thermal conditions and soil permeability). Projections suggest only moderate increases in sediment loss, occurring mainly in summer and winter. A sharper increase is projected in both catchments for TN losses, especially in the Barycz catchment characterized by a more intensive agriculture. The signal of change in annual TP losses is blurred by climate model uncertainty in the Barycz catchment, whereas a weak and uncertain increase is projected in the Upper Narew catchment
Extreme weather and climate in Europe
This report describes the current scientific knowledge of extreme weather and climate events in Europe for the following variables: temperature, precipitation, hail, and drought (with the following types of drought: meteorological, hydrological and soil moisture). The content summarises key literature drawn from peer reviewed journals and other sources (business and government reports), and builds upon the synthesised results presented in international assessments such as IPCC reports. It describes the recorded observations and modelled projections for extreme events including definitions, frequency, trends, spatial and temporal distribution. The report also presents an overview of the indices used to characterise extreme events as well as their main uses, before going on to describe the datasets where they are recorded, and provides information on the strengths and weaknesses of the indices and the datasets. Extra consideration is given to indices that are relevant to socio-economic impacts resulting from climate change and relevant statistical techniques for analysing extreme events. Observed changes in global climate and extreme events provide the context to the changes in extreme events observed in Europe, which are described for much of the 20th century. Modelled projections of extreme events are also given, under different emissions scenarios and time horizons, including results from regional models covering the European domain, such as EURO-CORDEX. The report is written for climate scientists, climate researchers and experts who use climate information in a professional role. There are four case studies (Appendix 2) which provide an anatomy of different recent European extreme weather/climate events including meteorological impacts and synoptic context.
Observed global temperature trends show the number of warm extremes has increased and number of cool extremes has decreased over the last 100 years, and the length and frequency of summer heat waves has increased during the last century. In Europe these trends are most pronounced in the last 40 years although regional variations exist. For Europe, 2014 was the warmest year on record, although it had fewer hot days than recent years. Under future climate change with continued warming, the number of heat waves is projected to increase, along with their duration and intensity. Under all emissions scenarios, summers like the hot summer experienced in 2003 will become commonplace by the 2040s.
The global trend in precipitation is generally for wetter conditions over the 20th century although changes are less temporally and spatially coherent than those observed for temperature. The general trend in precipitation for Europe in the 20th century is of increases over northern Europe and decreases over southern Europe. Extreme precipitation is becoming more intense and more frequent in Europe, especially in central and eastern Europe in winter, often resulting in greater and more frequent flooding. Since 1950 winter wet spells increased in duration in northern Europe and reduced in southern Europe, while summer wet spells became shorter in northern and eastern Europe. An increasing proportion of total rainfall is observed to fall on heavy rainfall days. Extreme precipitation (including short intense convective or longer duration frontal types) demonstrates complex variability and lacks a robust spatial pattern. Climate models project that events currently considered extreme are expected to occur more frequently in the future. For example a 1-in-20 year annual maximum daily precipitation amount is likely to become a 1-in-5 to 1-in-15 year event by the end of the 21st century in many parts of Europe.
There are few ground based hail observation networks, so satellite measurements and weather models are used to identify hail forming conditions. In Europe most extreme hail events occur in the summer over Central Europe and the Alps where convective energy is greatest. Intense hail events are linked to increases in convective energy in the atmosphere observed over the last 30 years. Hailstorm projection studies, although limited to France, northern Italy and Germany, show increases in the convective conditions that lead to hail and some areas show a rise in damage days although this is not statistically significant.
Recent severe droughts include Italy (1997-2002), the Baltic countries 2005-2009, the European heatwave of summer 2003, and the widespread European drought of 2011. The 1950s were prone to long, intense, Europe-wide meteorological and hydrological droughts. In northern and eastern Europe the highest drought frequency and severity was from the early 1950s to the mid-1970s. Southern and Western Europe (especially the Mediterranean) show the highest drought frequency and severity since 1990. There has been a small but continuous increase of the European areas prone to drought from the 1980s to the early 2010s. Regional climate models project a decrease in summer precipitation until 2100 of 17%. Dry periods are expected to occur 3 times more often at the end of this century and to last longer by 1 to 3 days compared to the period of 1971-2000. There is significant uncertainty associated with future projections of drought, with climate variability being the dominant source of uncertainty in observed and projected soil moisture drough
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