青藏高原与中国其他地区气候突变时间的比较

基于1961～2006年中国地面观测气温和降水资料，对青藏高原地区以及中国其他6个地区地表气温、降水的变化趋势和突变时间进行了检测和比较。结果发现，(1)地表气温:1961～2006年青藏高原地区年和四季的地表气温都呈增加趋势。年平均地表气温在20世纪80年代中期开始变暖，但显著快速增暖的突变发生在90年代中期，该时间比东北、华北、西北和淮河地区晚，与长江中下游和华南地区接近，不同季节青藏高原地区与其他地区变暖突变时间的差别也各有不同，但所有季节快速变暖突变的时间都比东北地区晚，中国东部陆地地区年和冬季平均地表气温表现出北早南晚的经向差异；(2)降水:1961～2006年青藏高原地区年降水量没有检测到显著的变化趋势，冬春降水量显著增加，而夏季降水有微弱的减少，秋季降水显著减少。降水突变的信号明显比温度突变的信号弱，年降水量和春季降水都没有检测到突变的发生，降水突变方向(增或减)和突变时间在区域与区域之间以及不同季节之间都存在较大差异。由上可见，青藏高原气候的显著快速变化比中国东部长江以北地区有明显的滞后现象，尤其是冬春温度变化，这可能是由于青藏高原地区积雪增加导致的反照率增加和冰川融化吸热对青藏高原变暖的减弱作用所致。

Intercomparison of the Time for Climate Abrupt Change between the Tibetan Plateau and Other Regions in China

Based on the station observation data from 1961 to 2006 in China,the trends and time points of abrupt change for surface air temperature(SAT) and precipitation are analyzed.The results show that,(1) for SAT,the annual and seasonal mean SAT in the Tibetan Plateau(TP) have shown increase trends,and the annual mean SAT begins to increase from the mid-1980s while the fast and significant increase in SAT starts from the mid-1990s,which is later than that in Northeast China,North China,Northwest China,and the Huaihe River regions,and similar to that in the middle and lower reaches of the Yangtze River and South China;in all seasons,the climate jumping points for fast increase of SAT in TP are all later than that in Northeast China;and the detection for annual and winter mean temperature shows significant meridional difference,earlier in the northern area and later in the southern area,in East China;(2) for precipitation,there is no significant trend for the annual precipitation,while that in winter and spring increases significantly,that in summer decreases weakly and that in autumn decreases significantly.The signals of climate jump for precipitation are weaker than those of SAT,and no sudden changes are detected for annual and spring precipitation;there are large differences in the direction and time for climate jump of precipitation.According to the above analysis,the significant fast climate change in TP is later than that in the areas to the north of the Yangtze River in East China,especially in winter and spring,which likely results from the increase of albedo due to increase of snow cover and the melting of glaciers.