scholarly journals The response of precipitation characteristics to global warming from global and regional climate projections

2018 ◽  
Author(s):  
Filippo Giorgi ◽  
Francesca Raffaele ◽  
Erika Coppola
Keyword(s):  
Global Warming ◽  
Climate Model ◽  
Regional Climate ◽  
Climate Projections ◽  
Potential Predictability ◽  
Precipitation Characteristics ◽  
Dry Spell ◽  
The Difference ◽  
Regional Climate Projections ◽  
Precipitation Events

Abstract. We revisit the issue of the response of the precipitation characteristics to global warming based on analyses of global and regional climate model projections for the 21st century. The prevailing response we identify can be summarized as follows: increase in the intensity of precipitation events and extremes, with the occurrence of events of unprecedented magnitude, i.e. magnitude not found in present day climate; decrease in the number of light precipitation events and in wet spell lengths; increase in the number of dry days and dry spell lengths. This response, which is mostly consistent across the models we analized, is tied to the difference between precipitation intensity responding to increases in local humidity conditions, especially for heavy and extreme events, and mean precipitation responding to slower increases in global evaporation. These changes in hydroclimatic characteristics have multiple and important impacts on the Earth's hydrologic cycle and on a variety of sectors, and as examples we investigate effects on the potential stress due to increases in dry and wet extremes, changes in precipitation interannual variability and changes in potential predictability of precipitation events. We also stress how the understanding of the hydroclimatic response to global warming can shed important insights into the fundamental behavior of precipitation processes, most noticeably tropical convection.

scholarly journals The response of precipitation characteristics to global warming from climate projections

2019 ◽  
Vol 10 (1) ◽  
pp. 73-89 ◽  
Author(s):  
Filippo Giorgi ◽  
Francesca Raffaele ◽  
Erika Coppola
Keyword(s):  
Global Warming ◽  
Climate Model ◽  
Regional Climate ◽  
Climate Projections ◽  
Potential Predictability ◽  
Precipitation Characteristics ◽  
Dry Spell ◽  
The Difference ◽  
Light Precipitation ◽  
Precipitation Events

Abstract. We revisit the issue of the response of precipitation characteristics to global warming based on analyses of global and regional climate model projections for the 21st century. The prevailing response we identify can be summarized as follows: increase in the intensity of precipitation events and extremes, with the occurrence of events of “unprecedented” magnitude, i.e., a magnitude not found in the present-day climate; decrease in the number of light precipitation events and in wet spell lengths; and increase in the number of dry days and dry spell lengths. This response, which is mostly consistent across the models we analyzed, is tied to the difference between precipitation intensity responding to increases in local humidity conditions and circulations, especially for heavy and extreme events, and mean precipitation responding to slower increases in global evaporation. These changes in hydroclimatic characteristics have multiple and important impacts on the Earth's hydrologic cycle and on a variety of sectors. As examples we investigate effects on potential stress due to increases in dry and wet extremes, changes in precipitation interannual variability, and changes in the potential predictability of precipitation events. We also stress how the understanding of the hydroclimatic response to global warming can provide important insights into the fundamental behavior of precipitation processes, most noticeably tropical convection.

scholarly journals Robustness of future atmospheric circulation changes over the EURO-CORDEX domain

2021 ◽  
Author(s):  
Tugba Ozturk ◽  
Dominic Matte ◽  
Jens Hesselbjerg Christensen
Keyword(s):  
Wind Speed ◽  
Atmospheric Circulation ◽  
Central Europe ◽  
Climate Model ◽  
Global Climate Model ◽  
Regional Climate ◽  
Climate Projections ◽  
Future Change ◽  
Ensemble Mean ◽  
Regional Climate Projections

AbstractEuropean climate is associated with variability and changes in the mid-latitude atmospheric circulation. In this study, we aim to investigate potential future change in circulation over Europe by using the EURO-CORDEX regional climate projections at 0.11° grid mesh. In particular, we analyze future change in 500-hPa geopotential height (Gph), 500-hPa wind speed and mean sea level pressure (MSLP) addressing different warming levels of 1 °C, 2 °C and 3 °C, respectively. Simple scaling with the global mean temperature change is applied to the regional climate projections for monthly mean 500-hPa Gph and 500-hPa wind speed. Results from the ensemble mean of individual models show a robust increase in 500-hPa Gph and MSLP in winter over Mediterranean and Central Europe, indicating an intensification of anticyclonic circulation. This circulation change emerges robustly in most simulations within the coming decade. There are also enhanced westerlies which transport warm and moist air to the Mediterranean and Central Europe in winter and spring. It is also clear that, models showing different responses to circulation depend very much on the global climate model ensemble member in which they are nested. For all seasons, particularly autumn, the ensemble mean is much more correlated with the end of the century than most of the individual models. In general, the emergence of a scaled pattern appears rather quickly.

scholarly journals Independence of Future Changes of River Runoff in Europe from the Pathway to Global Warming

2020 ◽  
Author(s):  
Lorenzo Mentaschi ◽  
Lorenzo Alfieri ◽  
Francesco Dottori ◽  
Carmelo Cammalleri ◽  
Berny Bisselink ◽  
...  
Keyword(s):  
Global Warming ◽  
Climate Model ◽  
Statistical Significance ◽  
Regional Climate ◽  
Climate Impact ◽  
Major Loss ◽  
Floods And Droughts ◽  
The Difference ◽  
Projected Changes ◽  
Time Frames

The outcomes of the 2015 Paris Agreement triggered a number of climate impact assessments, such as for floods and droughts, to focus on future time frames corresponding to the years of reaching specific levels of global warming. Yet, the links between the timing of the warming levels and the corresponding greenhouse gas concentration pathways to reach them, remain poorly understood. To address this gap, we compare projected changes of annual mean, extreme high and extreme low river discharges in Europe at 1.5°C and 2°C under scenarios RCP8.5 and RCP4.5 from an ensemble of Regional Climate Model (RCM) simulations. The statistical significance of the difference between the two scenarios for both warming levels is then evaluated. Results show that in the majority of Europe (>95% of the surface area for the annual mean discharge, >98% for high and low extremes), the changes projected in the two pathways are statistically indistinguishable. These results suggest that in studies of changes at specific warming levels the projections of the two pathways can be merged into a single ensemble without major loss of information. With regard to the uncertainty of the unified ensemble, findings show that the projected changes of annual mean, extreme high and extreme low river discharge are statistically significant in large portions of Europe.

scholarly journals Recent past (1979–2014) and future (2070–2099) isoprene fluxes over Europe simulated with the MEGAN–MOHYCAN model

2018 ◽  
Vol 15 (12) ◽  
pp. 3673-3690 ◽  
Author(s):  
Maite Bauwens ◽  
Trissevgeni Stavrakou ◽  
Jean-François Müller ◽  
Bert Van Schaeybroeck ◽  
Lesley De Cruz ◽  
...  
Keyword(s):  
Climate Model ◽  
Regional Climate ◽  
Co2 Concentration ◽  
Climate Projections ◽  
Emission Model ◽  
Recent Past ◽  
Rcp Scenarios ◽  
Control Simulation ◽  
Direct Emission ◽  
The Difference

Abstract. Isoprene is a highly reactive volatile organic compound emitted by vegetation, known to be a precursor of secondary organic aerosols and to enhance tropospheric ozone formation under polluted conditions. Isoprene emissions respond strongly to changes in meteorological parameters such as temperature and solar radiation. In addition, the increasing CO2 concentration has a dual effect, as it causes both a direct emission inhibition as well as an increase in biomass through fertilization. In this study we used the MEGAN (Model of Emissions of Gases and Aerosols from Nature) emission model coupled with the MOHYCAN (Model of HYdrocarbon emissions by the CANopy) canopy model to calculate the isoprene fluxes emitted by vegetation in the recent past (1979–2014) and in the future (2070–2099) over Europe at a resolution of 0.1∘×0.1∘. As a result of the changing climate, modeled isoprene fluxes increased by 1.1 % yr−1 on average in Europe over 1979–2014, with the strongest trends found over eastern Europe and European Russia, whereas accounting for the CO2 inhibition effect led to reduced emission trends (0.76 % yr−1). Comparisons with field campaign measurements at seven European sites suggest that the MEGAN–MOHYCAN model provides a reliable representation of the temporal variability of the isoprene fluxes over timescales between 1 h and several months. For the 1979–2014 period the model was driven by the ECMWF ERA-Interim reanalysis fields, whereas for the comparison of current with projected future emissions, we used meteorology simulated with the ALARO regional climate model. Depending on the representative concentration pathway (RCP) scenarios for greenhouse gas concentration trajectories driving the climate projections, isoprene emissions were found to increase by +7 % (RCP2.6), +33 % (RCP4.5), and +83 % (RCP8.5), compared to the control simulation, and even stronger increases were found when considering the potential impact of CO2 fertilization: +15 % (RCP2.6), +52 % (RCP4.5), and +141 % (RCP8.5). However, the inhibitory CO2 effect goes a long way towards canceling these increases. Based on two distinct parameterizations, representing strong or moderate inhibition, the projected emissions accounting for all effects were estimated to be 0–17 % (strong inhibition) and 11–65 % (moderate inhibition) higher than in the control simulation. The difference obtained using the two CO2 parameterizations underscores the large uncertainty associated to this effect.

scholarly journals Independence of Future Changes of River Runoff in Europe from the Pathway to Global Warming

Climate ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 22
Author(s):  
Lorenzo Mentaschi ◽  
Lorenzo Alfieri ◽  
Francesco Dottori ◽  
Carmelo Cammalleri ◽  
Berny Bisselink ◽  
...  
Keyword(s):  
Global Warming ◽  
Climate Model ◽  
Statistical Significance ◽  
Regional Climate ◽  
Climate Impact ◽  
Major Loss ◽  
Floods And Droughts ◽  
The Difference ◽  
Projected Changes ◽  
Time Frames

The outcomes of the 2015 Paris Agreement triggered a number of climate impact assessments, such as for floods and droughts, to focus on future time frames corresponding to the years of reaching specific levels of global warming. Yet, the links between the timing of the warming levels and the corresponding greenhouse gas concentration pathways to reach them remain poorly understood. To address this gap, we compared projected changes of annual mean, extreme high, and extreme low river discharges in Europe at 1.5 °C and 2 °C under Representative Concentration Pathways RCP8.5 and RCP4.5 from an ensemble of regional climate model (RCM) simulations. The statistical significance of the difference between the two scenarios for both warming levels was then evaluated. The results show that in the majority of Europe (>95% of the surface area for the annual mean discharge, >98% for high and low extremes), the changes projected in the two pathways were statistically indistinguishable. These results suggest that in studies of changes at global warming levels, the projections of the two pathways can be merged into a single ensemble without major loss of information. With regard to the uncertainty of the unified ensemble, the findings show that the projected changes of annual mean, extreme high, and extreme low river discharge were statistically significant in large portions of Europe.

scholarly journals Recent past (1979–2014) and future (2070–2099) isoprene fluxes over Europe simulated with the MEGAN-MOHYCAN model

2017 ◽  
Author(s):  
Maite Bauwens ◽  
Trissevgeni Stavrakou ◽  
Jean-François Müller ◽  
Bert Van Schaeybroeck ◽  
Lesley De Cruz ◽  
...  
Keyword(s):  
Climate Model ◽  
Regional Climate ◽  
Co2 Concentration ◽  
Hydrocarbon Emissions ◽  
Climate Projections ◽  
Emission Model ◽  
Recent Past ◽  
Control Simulation ◽  
Direct Emission ◽  
The Difference

Abstract. Isoprene is a highly reactive volatile organic compound emitted by vegetation, known to be a precursor of secondary organic aerosol and to enhance tropospheric ozone formation under polluted conditions. Isoprene emissions respond strongly to changes in meteorological parameters such as temperature and solar radiation; in addition, the increasing CO2 concentration has a dual effect, as it causes both a direct emission inhibition as well as an increase in biomass through fertilization. In this study we used the MEGAN (Model of Emissions of Gases and Aerosols from Nature) emission model coupled with the MOHYCAN (Model of HYdrocarbon emissions by the CANopy) canopy model to calculate the isoprene fluxes emitted by vegetation in the recent past (1979–2014) and in the future (2070–2099) over Europe at a resolution of 0.1° × 0.1°. As a result of the changing climate, modeled isoprene fluxes increased by 1.1 % yr−1 on average in Europe over 1979–2014, with the strongest trends found over eastern Europe and European Russia, whereas accounting also for the CO2 inhibition effect led to reduced emission trends (0.76 % yr−1). Comparisons with field campaign measurements at seven European sites suggest that the MEGAN-MOHYCAN model provides a reliable representation of the temporal variability of the isoprene fluxes over time scales between 1 hour to several months. For the 1979–2014 period the model was driven by the ECMWF ERA-Interim reanalysis fields, whereas for the comparison of current with projected future emissions, we used meteorology simulated with the ALARO regional climate model. Depending on the representative concentration pathways (RCPs) scenarios for greenhouse gas concentration trajectories driving the climate projections, isoprene emissions were found to increase as a result of climate change by +7 % (RCP2.6), +33 % (RCP4.5) and +83 % (RCP8.5), compared to the control simulation, and even stronger increases were found when considering the potential impact of CO2 fertilization, +15 % (RCP2.6), +52 % (RCP4.5) and +141 % (RCP8.5). However, the inhibitory CO2 effect goes a long way in cancelling these increases. Based on two distinct parameterizations, representing strong or moderate inhibition, the projected emissions accounting for all effects were estimated to be 0–17 % (strong inhibition) and 11–65 % (moderate inhibition) higher than in the control simulation. The difference obtained using the two CO2 parameterizations underscores the large uncertainty associated to this effect.

scholarly journals Independence of Future Changes of River Runoff in Europe from the Pathway to Global Warming

2019 ◽  
Author(s):  
Lorenzo Mentaschi ◽  
Lorenzo Alfieri ◽  
Francesco Dottori ◽  
Carmelo Cammalleri ◽  
Berny Bisselink ◽  
...  
Keyword(s):  
Global Warming ◽  
Climate Model ◽  
Statistical Significance ◽  
Regional Climate ◽  
Climate Impact ◽  
Major Loss ◽  
Floods And Droughts ◽  
The Difference ◽  
Projected Changes ◽  
Time Frames

The outcomes of the 2015 Paris Agreement triggered a number of climate impact assessments, such as for floods and droughts, to focus on future time frames corresponding to the years of reaching specific levels of global warming. Yet, the links between the timing of the warming levels and the corresponding greenhouse gas concentration pathways to reach them, remain poorly understood. To address this gap, we compare projected changes of annual mean, extreme high and extreme low river discharges in Europe at 1.5° and 2° under scenarios RCP8.5 and RCP4.5 from an ensemble of Regional Climate Model (RCM) simulations. The statistical significance of the difference between the two scenarios for both warming levels is then evaluated. Results show that in the majority of Europe (>95% for the annual mean discharge, >98% for high and low extremes), the changes projected in the two pathways are statistically indistinguishable. These results suggest that in studies of changes at specific warming levels the projections of the two pathways can be merged into a single ensemble without major loss of information. With regard to the uncertainty of the unified ensemble, findings show that the projected changes of annual mean, extreme high and extreme low river discharge are statistically significant in large portions of Europe.

scholarly journals Higher Hydroclimatic Intensity with Global Warming

2011 ◽  
Vol 24 (20) ◽  
pp. 5309-5324 ◽  
Author(s):  
F. Giorgi ◽  
E.-S. Im ◽  
E. Coppola ◽  
N. S. Diffenbaugh ◽  
X. J. Gao ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Global Warming ◽  
Climate Model ◽  
Regional Climate ◽  
Precipitation Intensity ◽  
Detection And Attribution ◽  
Dry Spell ◽  
Late Twentieth ◽  
Late Twentieth Century ◽  
Spell Length

Abstract Because of their dependence on water, natural and human systems are highly sensitive to changes in the hydrologic cycle. The authors introduce a new measure of hydroclimatic intensity (HY-INT), which integrates metrics of precipitation intensity and dry spell length, viewing the response of these two metrics to global warming as deeply interconnected. Using a suite of global and regional climate model experiments, it is found that increasing HY-INT is a consistent and ubiquitous signature of twenty-first-century, greenhouse gas–induced global warming. Depending on the region, the increase in HY-INT is due to an increase in precipitation intensity, dry spell length, or both. Late twentieth-century observations also exhibit dominant positive HY-INT trends, providing a hydroclimatic signature of late twentieth-century warming. The authors find that increasing HY-INT is physically consistent with the response of both precipitation intensity and dry spell length to global warming. Precipitation intensity increases because of increased atmospheric water holding capacity. However, increases in mean precipitation are tied to increases in surface evaporation rates, which are lower than for atmospheric moisture. This leads to a reduction in the number of wet days and an increase in dry spell length. This analysis identifies increasing hydroclimatic intensity as a robust integrated response to global warming, implying increasing risks for systems that are sensitive to wet and dry extremes and providing a potential target for detection and attribution of hydroclimatic changes.

Regional Climate Scenarios for use in Nordic Water Resources Studies

2003 ◽  
Vol 34 (5) ◽  
pp. 399-412 ◽  
Author(s):  
M. Rummukainen ◽  
J. Räisänen ◽  
D. Bjørge ◽  
J.H. Christensen ◽  
O.B. Christensen ◽  
...  
Keyword(s):  
Water Resources ◽  
Climate Models ◽  
Global Climate ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Climate Projections ◽  
Climate Scenarios ◽  
Soil Frost ◽  
Nordic Region ◽  
Regional Climate Projections

According to global climate projections, a substantial global climate change will occur during the next decades, under the assumption of continuous anthropogenic climate forcing. Global models, although fundamental in simulating the response of the climate system to anthropogenic forcing are typically geographically too coarse to well represent many regional or local features. In the Nordic region, climate studies are conducted in each of the Nordic countries to prepare regional climate projections with more detail than in global ones. Results so far indicate larger temperature changes in the Nordic region than in the global mean, regional increases and decreases in net precipitation, longer growing season, shorter snow season etc. These in turn affect runoff, snowpack, groundwater, soil frost and moisture, and thus hydropower production potential, flooding risks etc. Regional climate models do not yet fully incorporate hydrology. Water resources studies are carried out off-line using hydrological models. This requires archived meteorological output from climate models. This paper discusses Nordic regional climate scenarios for use in regional water resources studies. Potential end-users of water resources scenarios are the hydropower industry, dam safety instances and planners of other lasting infrastructure exposed to precipitation, river flows and flooding.

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