【摘要】 利用宁夏20个气象站1961—2004年基本气象资料,结合同期NCEP/NCAR全球月平均再分析资料,对近44 a气温变化趋势及气温偏暖和偏冷时段的环流背景场特征,以及气温典型偏高和偏低年的环流差异特征进行合成对比诊断分析。结果表明:1961年以来,宁夏气温总体呈上升态势,60年代,气温为偏冷时段,90年代以后处于气温显著上升的偏暖时段;在偏冷时段,极涡位于贝加尔湖北部,河套地区受贝加尔湖东部低压底部平直气流控制;在偏暖时段,东亚大槽相对偏东,河套地区受较强的西北气流控制。气温偏高年,乌拉尔山冷低压强度偏弱,亚洲北部的冷空气主体偏北,河套地区主要受偏东气流控制,宁夏处于温度正距平区;气温偏低年,极地到贝加尔湖附近冷空气东移南下,河套地区西风明显加强,宁夏位于强的温度负距平中心的底部。气温偏高和偏低年的环流分布特征与偏暖和偏冷时段的环流背景场基本一致。更多还原

【Abstract】 Based on the temperature data at 20 stations in Ningxia in 1961—2004 and the NCEP/NCAR monthly global reanalysis data in the same period,trends of temperature in the recent 44 years in Ningxia are analyzed,and the characters of background circulation fields for warm and cold periods and the circulation differences between typical warm and cold years are compositely analyzed in this paper.The analysis results show that since 1961,temperature in Ningxia has generally increased,with the 1960s being a colder period,and the 1990s being a rapid warming period.The seasonal temperature increased most in winter,but least in summer.The station number of high temperature has increased gradually since 1986,remarkably after 1998.On the other hand,the station number of low temperature were more from the 1960s to the mid 1980s.In the warm years,the Ural cold low was relatively weak,the main cold air in northern Asia located north of normal,the easterly flow dominated over Ningxia,and therefere Ningxia was in the positive temperature departure area;but in the cold years,the cold air from the polar region and the Baikal lake region was piled up in Mongolia,the westerly wind over Ningxia was clearly strengthened,and Ningxia was in the bottom area of the negative departure of temperature.更多还原