藏北羌塘高原气候变化的时空格局  

Spatio-temporal Pattern of Climate Changes in Northern Tibet's Qiangtang Plateau

作　　者：王景升[1] 张宪洲[1] 赵玉萍[1] 沈振西[1] 石培礼[1] 余成群[1] 

机构地区：[1]中国科学院地理科学与资源研究所,北京100101

出　　处：《资源科学》2008年第12期1852-1859,共8页Resources Science

基　　金：国家科技支撑计划课题:"西藏高寒干旱退化生态系统恢复技术研究"(编号:2006BAC01A04);"藏北高寒草甸区生态稳定性维持技术研究与示范"(编号:2007BAC06B01);国家科技部973项目"05G50292AI"课题资助

摘　　要：藏北的羌塘高原作为青藏高原的主体和核心，是对全球变化反应最敏感的区域之一。本文通过统计藏北高原仅有的8个气象站50年来温度、降水等资料，计算分析了PER、RDI，运用植被-气候综合模型计算分析了NPP的变化量，探讨了藏北气候空间格局和随时间变化的规律。结果表明：藏北东部由南向北地势升高，温度和降水呈减少趋势，温度可能是限制藏北东部生产力的主要因子；藏北地区由东向西，降水量迅速减少，P职和RDI增加，气候渐趋干旱；其它气象因子变化复杂，与地形和植被等多种因素有关。1955年～2004年整个藏北地区温度增加趋势明显，平均增温幅度为1．4℃；降水量东部、中部增加75—115mm，西部无明显变化；〉0℃日数增加11～20天；PE尺和RDI西部增加，中部、东部无明显变化；1980年以来，水汽压普遍增加，云量和风速均呈减少趋势。藏北地区升温主要发生在秋、冬季，增温幅度分别为1．6℃、1．8℃，春、夏季温度增幅为1．25℃、0．8℃。降水增加以春、夏、秋季为主，春夏秋冬增量分别为22mm、20mm、20mm、6．5mm。气候变化复杂，NPP整体上呈增加趋势，但空间格局上有差异，20世纪80年代以来，东部NPP增加，西部NPP减少，气候因素仍然是藏北西部草地退化的直接威胁。The Northern Tibet Plateau is at the center of the Qing-Tibet Plateau, and is one of the most sensitive areas to global climate change. In this study, we calculated the potential evapotranspiration rate （PER） and radiation dryness index （RDI） using an analysis of daily meteorological data from 1955 -2004 from 8 meteorological stations located in the Northern Tibet Plateau. Then we analyzed the spatial and temporal patterns of climate change and Net Primary Productivity （NPP） of vegetation in the study area, which was determined using a vegetation-climate model. Results show that in the eastern part of our study area, annual mean temperature and annual precipitation decreased gradually from south to north, in accordance with an increase in elevation. Temperature might be the key constraint on NPP in this region. From east to west, annual precipitation decreased, and PER and RDI increased. Thus, it was increasingly dry from east to west. The spatial patterns of other meteorological factors showed complexity, and these may be affected by topography, vegetation and many other factors. During the period of 1955 ~ 2004, the climate became warmer, with an annual mean temperature increase of 1.4℃ in the Northern Tibet Plateau. In the central and eastern regions, there was an increase of 75 - 115mm in annual precipitation, but no significant increase in the western part. The number of days with a daily mean temperature higher than 0 ℃ increased by 11 - 20 days yearly, and PER and RDI increased in the western part with no significant changes in the central and eastern part. Additionally, hydrosphere pressure increased, but cloudiness and wind speed decreased after 1980. Overall, there was a wetter climate in the eastern part and a drier climate in the western part of the study area. From 1955 to 2004, the seasonal pattern of warming and trend of annual precipitation increase is as follows. From spring to winter, the seasonal mean temperature increased by 1.25 ℃, 0.8℃, 1.6℃, and 1.8℃ respectively

关 键 词：藏北 变化 NPP 时空格局 

分 类 号：P467[天文地球—大气科学及气象学] P588.14