Zonal mean annual temperature trends were estimated using four reanalysis and three analysis grid datasets.The trends over land and for the entire globe were estimated from 1958-2001 and 1979-2007,respectively.Estimates of temperature trends over land from Climate Research Unit (CRU) analysis data indicate more intense warming moving northward,at a rate of about 3.5℃ per century at 65°N,then declining further to the north.CRU estimates indicated dramatic warming over the latitudes of the Antarctic Peninsula,with a localized cooling trend at 45°S.A global estimate was conducted by comparing estimates of the reanalysis datasets.Temperature distribution trends of the reanalysis data were similar to those generated by land observations but with large bias in the Polar Regions.The bias could be reduced by comparing these estimates with those from the analysis data at high latitudes.Extreme warming trends were estimated at rates of 2.9℃-3.5℃ per century in the Arctic and 3.2℃-4.7℃ per century in the Antarctic for 1958-2001.Surface warming was even more intense in the Northern Hemisphere for 1979-2007,with extreme arctic warming rates ranging from 8.5℃-8.9℃ per century,as estimated by the analysis and reanalysis datasets.Trends over Antarctica for this period were contradictory,as Japan Meteorological Agency (JMA) reanalysis (JRA-25) indicated a cooling trend at about 7℃ per century,while other reanalysis datasets showed sharp warming over the continent.
利用CRU（Climatic Research Unit）的全球格点月降水及月平均气温资料，通过计算地表湿润指数分析了1951～2002年全球干湿变化趋势．重点对比研究了北美大陆、南美大陆、欧亚大陆、非洲大陆及澳洲大陆干湿变化的特征及差异，并在此基础上对各大陆乃至全球的干湿变化与影响气候变化的大尺度背景的相关关系进行了分析．结果表明，在增暖背景下，20世纪下半叶全球干湿变化趋势具有明显的区域差异，非洲大陆、欧亚大陆、澳洲大陆和南美大陆近52年主要以干旱化趋势为主，尤以非洲大陆和欧亚大陆最为剧烈．北美大陆在1976年以后表现为变湿趋势，南美大陆存在30年左右的干湿振荡周期，但最近仍然处于干化的时段，澳洲大陆的变化与之类似．研究还表明，增暖已经改变了全球环境干湿变化的分布格局，南美大陆和澳洲大陆尽管降水为增加趋势，但仍然表现为干旱化趋势，其中温度升高是其表现为干旱化特征不可忽视的原因．全球环境的干湿变化与大尺度背景密切相关：非洲大陆、欧亚大陆的干旱化趋势、北美大陆的湿化趋势与北太平洋年代际振荡（PDO）显著相关；而南美大陆、澳洲大陆干湿的年代际振荡与南方涛动指数（SOI）的年代际变化一致．
