Climate change in the 21st century over China is simulated using the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model version 3 (RegCM3). The model is one-way nested within the gl...
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Climate change in the 21st century over China is simulated using the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model version 3 (RegCM3). The model is one-way nested within the global model CCSR/NIES/FRCGC MIROC3.2_hires (Center for Climate System Research/National Institute for Environmental Studies/Frontier Research Center for Global Change/Model for Interdisciplinary Research on Climate). A 150-year (1951-2100) transient simulation is conducted at 25 km grid spacing, under the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) A1B scenario. Simulations of present climate conditions in China by RegCM3 are compared against observations to assess model performance. Results show that RegCM3 reproduces the observed spatial structure of surface air temperature and precipitation well. Changes in mean temperature and precipitation in December-January-February (DJF) and June-July-August (JJA) during the middle and end of the 21st century are analyzed. Significant future warming is simulated by RegCM3. This warming becomes greater with time, and increased warming is simulated at high latitude and high altitude (Tibetan Plateau) areas. In the middle of the 21st century in DJF, a general increase of precipitation is found in most areas, except over the Tibetan Plateau. Precipitation changes in JJA show an increase over northwest China and a decrease over the Tibetan Plateau. There is a mixture of positive and negative changes in eastern China. The change pattern at the end of the century is generally consistent with that in mid century, except in some small areas, and the magnitude of change is usually larger. In addition, the simulation is compared with a previous simulation of the RegCM3 driven by a different global model, to address uncertainties of the projected climate change in China.
本研究透过蒙地卡罗法之模拟以评量Hsiao et al. (2012) 提出的纵横资料反事实法(Panel-Data Counterfactual Method)与 Abadie et al. (2010) 提出的合成对照组法(Synthetic Control Method)之人工对照组估计之准确度。在使用主体之选...
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本研究透过蒙地卡罗法之模拟以评量Hsiao et al. (2012) 提出的纵横资料反事实法(Panel-Data Counterfactual Method)与 Abadie et al. (2010) 提出的合成对照组法(Synthetic Control Method)之人工对照组估计之准确度。在使用主体之选择由资料产生,与具单位处理效果(Treatment effect)之估计方法中,何者对随时间变动之处理效果估计较佳为本研究之目标。将此二法,应用於多个实例资料,进行模拟及交叉比对,以评估其可用性。结果显示当共同因素在时间中的变动与因素负荷在地区间的变动均小时,此二法之估计均良好。但以均方差衡量对人工对照的估计时,纵横资料反事实法在大多数情况下, 比合成对照组法准确。尽管此二法均需谨慎使用,由蒙地卡罗模拟之结果显示,纵横资料反事实法明显较佳。
Frequent winter snowstorms have recently caused large economic losses and attracted wide *** snowstorms have raised an important scientific *** scenarios of future global warming,will winter precipitation in China inc...
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Frequent winter snowstorms have recently caused large economic losses and attracted wide *** snowstorms have raised an important scientific *** scenarios of future global warming,will winter precipitation in China increase significantly and produce more snow in the north? Using Coupled Model Intercomparison Project phase 3 (CMIP 3) model projections under the Special Report on Emissions Scenario A1B scenario,we generated a possible future Arctic condition,the summer (September) "ice-free Arctic" *** then used corresponding monthly sea surface temperature (SST) values and a set of CO 2 concentrations to drive an atmospheric general circulation model (AGCM),for simulating East Asian climate *** experimental results show that during the boreal winter (December-January-February;DJF),global surface air temperature would increase significantly under this scenario,producing substantial warming in Arctic regions and at high latitudes in Asia and North *** Siberian High,Aleutian Low and East Asian winter monsoon would all ***,because of increased transport of water vapor to China from the north,winter precipitation would increase from south to *** addition,the significant increase in winter temperature might cause fewer cold surges.
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