In this study,projected changes in the future climate conditions for the Middle EasteNorth Africa domain over the 21st century have been investigated.Two simulations with the COSMO-CLM model have been conducted respec...In this study,projected changes in the future climate conditions for the Middle EasteNorth Africa domain over the 21st century have been investigated.Two simulations with the COSMO-CLM model have been conducted respectively,at a spatial resolution of 0.44 and 0.22,over the period 1979e2100,employing the IPCC RCP4.5 scenario.Initial and boundary conditions have been derived by the global model CMCCCM.The main aim of the work is to provide regional climate projections for this area,widening the range of the data already available,yet with higher resolution,useful for many applications,especially as an input for the impact models.The two different resolutions have been employed in order to quantify the differences due to the spatial scale effects,comparing the results also with the driving global model.Climate projections show a significant warming expected over the whole area considered at the end of the 21st century,along with a reduction in precipitation,which is particularly evident over the western part of the domain.Precipitation projections depend on the horizontal resolution,suggesting the need for additional simulations at higher resolution,especially for a proper representation of extreme weather events.展开更多
We used daily maximum temperature data（1986–2100） from the COSMO-CLM（COnsortium for Small-scale MOdeling in CLimate Mode） regional climate model and the population statistics for China in 2010 to determine the fr...We used daily maximum temperature data（1986–2100） from the COSMO-CLM（COnsortium for Small-scale MOdeling in CLimate Mode） regional climate model and the population statistics for China in 2010 to determine the frequency, intensity, coverage, and population exposure of extreme maximum temperature events（EMTEs） with the intensity–area–duration method. Between 1986 and 2005（reference period）, the frequency, intensity, and coverage of EMTEs are 1330–1680 times yr^–1, 31.4–33.3℃, and 1.76–3.88 million km^2, respectively. The center of the most severe EMTEs is located in central China and 179.5–392.8 million people are exposed to EMTEs annually. Relative to 1986–2005, the frequency, intensity, and coverage of EMTEs increase by 1.13–6.84, 0.32–1.50, and15.98%–30.68%, respectively, under 1.5℃ warming; under 2.0℃ warming, the increases are 1.73–12.48, 0.64–2.76,and 31.96%–50.00%, respectively. It is possible that both the intensity and coverage of future EMTEs could exceed the most severe EMTEs currently observed. Two new centers of EMTEs are projected to develop under 1.5℃ warming, one in North China and the other in Southwest China. Under 2.0℃ warming, a fourth EMTE center is projected to develop in Northwest China. Under 1.5 and 2.0℃ warming, population exposure is projected to increase by 23.2%–39.2% and 26.6%–48%, respectively. From a regional perspective, population exposure is expected to increase most rapidly in Southwest China. A greater proportion of the population in North, Northeast, and Northwest China will be exposed to EMTEs under 2.0℃ warming. The results show that a warming world will lead to increases in the intensity, frequency, and coverage of EMTEs. Warming of 2.0℃ will lead to both more severe EMTEs and the exposure of more people to EMTEs. Given the probability of the increased occurrence of more severe EMTEs than in the past, it is vitally important to China that the global temperature increase is limited within 1.5℃.展开更多
文摘In this study,projected changes in the future climate conditions for the Middle EasteNorth Africa domain over the 21st century have been investigated.Two simulations with the COSMO-CLM model have been conducted respectively,at a spatial resolution of 0.44 and 0.22,over the period 1979e2100,employing the IPCC RCP4.5 scenario.Initial and boundary conditions have been derived by the global model CMCCCM.The main aim of the work is to provide regional climate projections for this area,widening the range of the data already available,yet with higher resolution,useful for many applications,especially as an input for the impact models.The two different resolutions have been employed in order to quantify the differences due to the spatial scale effects,comparing the results also with the driving global model.Climate projections show a significant warming expected over the whole area considered at the end of the 21st century,along with a reduction in precipitation,which is particularly evident over the western part of the domain.Precipitation projections depend on the horizontal resolution,suggesting the need for additional simulations at higher resolution,especially for a proper representation of extreme weather events.
基金Supported by the National Natural Science Foundation of China(41571494,41661144027,and 41671211)
文摘We used daily maximum temperature data（1986–2100） from the COSMO-CLM（COnsortium for Small-scale MOdeling in CLimate Mode） regional climate model and the population statistics for China in 2010 to determine the frequency, intensity, coverage, and population exposure of extreme maximum temperature events（EMTEs） with the intensity–area–duration method. Between 1986 and 2005（reference period）, the frequency, intensity, and coverage of EMTEs are 1330–1680 times yr^–1, 31.4–33.3℃, and 1.76–3.88 million km^2, respectively. The center of the most severe EMTEs is located in central China and 179.5–392.8 million people are exposed to EMTEs annually. Relative to 1986–2005, the frequency, intensity, and coverage of EMTEs increase by 1.13–6.84, 0.32–1.50, and15.98%–30.68%, respectively, under 1.5℃ warming; under 2.0℃ warming, the increases are 1.73–12.48, 0.64–2.76,and 31.96%–50.00%, respectively. It is possible that both the intensity and coverage of future EMTEs could exceed the most severe EMTEs currently observed. Two new centers of EMTEs are projected to develop under 1.5℃ warming, one in North China and the other in Southwest China. Under 2.0℃ warming, a fourth EMTE center is projected to develop in Northwest China. Under 1.5 and 2.0℃ warming, population exposure is projected to increase by 23.2%–39.2% and 26.6%–48%, respectively. From a regional perspective, population exposure is expected to increase most rapidly in Southwest China. A greater proportion of the population in North, Northeast, and Northwest China will be exposed to EMTEs under 2.0℃ warming. The results show that a warming world will lead to increases in the intensity, frequency, and coverage of EMTEs. Warming of 2.0℃ will lead to both more severe EMTEs and the exposure of more people to EMTEs. Given the probability of the increased occurrence of more severe EMTEs than in the past, it is vitally important to China that the global temperature increase is limited within 1.5℃.
