综合评价了全球性降水数据MSWEP(Multi-Source Weighted-Ensemble Precipitation)在祁连山区的适用性,解析了其在不同时空尺度上的误差特征,采用结合地面雨量资料GSOD(Global Surface Summary of the Day)订正后的MSWEP(Corrected MSWEP...综合评价了全球性降水数据MSWEP(Multi-Source Weighted-Ensemble Precipitation)在祁连山区的适用性,解析了其在不同时空尺度上的误差特征,采用结合地面雨量资料GSOD(Global Surface Summary of the Day)订正后的MSWEP(Corrected MSWEP,COMSWEP),重点探讨了祁连山地区降水的垂直分布特性。结果表明:(1)MSWEP在日、月、年等尺度上总体低估了研究区域地表降水,对暴雨及以上日降水事件存在比较严重的漏报,在雨季的精度要明显高于旱季;(2)相对于MSWEP,COMSWEP在各种时间尺度上与地表降水更为吻合,对雨季降水和年降水具有较好估计效果,但在旱季仍存在较明显系统偏差;(3)MSWEP和COMSWEP均表明祁连山区多年平均降水量在空间上呈由东至西递减、北坡略高于南坡的总体格局,而在时程上雨季降水主导了全年降水,但在不同分区和时间尺度上,COMSWEP降水量均明显高于MSWEP;(4)MSWEP和COMSWEP均反映祁连山地区东段最大降水高度带在3000 m左右,超过此高度带多年平均降水量变化甚小,而中段和西段多年平均降水量随海拔呈现先增加后降低的趋势,最大降水高度带分别位于4100 m和4500 m左右。展开更多
In order to provide a better benchmark for climate simulation programs, climate data at Global Historical Climatology Network (GHCN) and Global Summary of the Day (GSOD) archived by the National Climate Data Center (N...In order to provide a better benchmark for climate simulation programs, climate data at Global Historical Climatology Network (GHCN) and Global Summary of the Day (GSOD) archived by the National Climate Data Center (NCDC) are used to ascertain the nature of climate change over the last century. After data validation, about 6000 stations are considered globally to determine the change in mean temperature, and about 5000 stations to determine that change in maximum and minimum temperatures. Global nature of temperature and its change are presented separately for January and July. Both maximum and minimum daily temperatures are used in the analysis. Trend of global change in annual precipitation is also reported here. Least square linear regression is used to ascertain the nature of these changes. Global nature of temperatures in both January and July show bimodal distributions, with the geographical region between the tropics in one mode and the region outside the tropic in another mode. The individual distributions of temperatures of both these regions show separate and similar histograms. Results indicate that over the last century, temperature in January increased more than that during July. Furthermore the minimum temperature in each case increased more than the maximum temperature. Ten separate estimates of temperature change are obtained from the data presented here using different methods. Considering all these estimates, the mean rise in temperature during January was 2.19°C, and during July was 1.72°C. The geographical nature of the rise in temperature shows that though it rises in most locations, the temperature also reduces along eastern Asia, some parts of central Russia, along south-eastern Australia, and along the east coast of the United States. Predominant rise in temperature is mostly over Europe, and in the arctic. Change in precipitation shows that though there is significant reduction rainfall globally, rainfall increases along the equator, in areas around the Gulf of Mexico, along eastern Asia, along the western coast of India, and along the eastern coast of Australia.展开更多
文摘In order to provide a better benchmark for climate simulation programs, climate data at Global Historical Climatology Network (GHCN) and Global Summary of the Day (GSOD) archived by the National Climate Data Center (NCDC) are used to ascertain the nature of climate change over the last century. After data validation, about 6000 stations are considered globally to determine the change in mean temperature, and about 5000 stations to determine that change in maximum and minimum temperatures. Global nature of temperature and its change are presented separately for January and July. Both maximum and minimum daily temperatures are used in the analysis. Trend of global change in annual precipitation is also reported here. Least square linear regression is used to ascertain the nature of these changes. Global nature of temperatures in both January and July show bimodal distributions, with the geographical region between the tropics in one mode and the region outside the tropic in another mode. The individual distributions of temperatures of both these regions show separate and similar histograms. Results indicate that over the last century, temperature in January increased more than that during July. Furthermore the minimum temperature in each case increased more than the maximum temperature. Ten separate estimates of temperature change are obtained from the data presented here using different methods. Considering all these estimates, the mean rise in temperature during January was 2.19°C, and during July was 1.72°C. The geographical nature of the rise in temperature shows that though it rises in most locations, the temperature also reduces along eastern Asia, some parts of central Russia, along south-eastern Australia, and along the east coast of the United States. Predominant rise in temperature is mostly over Europe, and in the arctic. Change in precipitation shows that though there is significant reduction rainfall globally, rainfall increases along the equator, in areas around the Gulf of Mexico, along eastern Asia, along the western coast of India, and along the eastern coast of Australia.
