基于陆面模式NCAR/CLM3.5的东北区域生长季地表干湿状况时空分布特征模拟研究

利用东北地区地面102站56 a(1951~2006年)逐日气象观测资料,驱动NCAR陆面模式CLM 3.5,模拟东北地区生长季地表水分盈余量(Surface Water Surplus,SWS),探讨和分析了东北地区生长季1951~2006年地表干湿状况的时空变化规律。结果表明:1971~2000年平均东北地区生长季SWS反映的地表干湿状况具有较大的地域差异,全区SWS为100~800 mm;中、西部为SWS低值区,属半干旱、半湿润区;东、南、北部为相对高值区,属湿润、半湿润区。生长季地表干湿状况存在显著的年际、年代际变化;56 a来,东北地区生长季SWS呈线性减少趋势,即地表变干,SWS空间分布的年代际变化,同样表现为变干趋势,尤其2000~2006年是地表变干最为显著的时期,表明在全球变暖背景下东北地区地表干旱化趋势增强。分析表明地表干湿状况是下垫面与气候变化共同作用的结果,研究地表干湿状况需要综合考虑水分收支项。

Spatial-Temporal Characteristics of Surface Dry/Wet Status in Northeast China by NCAR/CLM3.5

Long term(1951-2006) Surface Water Surplus(SWS) for growing season(May to September) over Northeast China is produced by NCAR CLM3.5,which is driven by daily observations from 102 meteorological stations.Temporal-spatial variability of surface dry/wet status is analyzed based on the CLM3.5 simulation.The results show that,1) in growing season,30 year(1971-2000) averaged SWS has relatively large spatial difference,with regional SWS ranging from 100 to 800 mm.Higher SWS value locates over eastern,southern and northern parts of analysis domain,indicating a wetter condition over the area.2) Significant inter-annual and decadalvariabilities are detected in CLM3.5 results;3) Over Northeast China the SWS has decline trend showing that the surface has been drying during past 50 years.The drying signal is also found in decadal variance of spatial distribution of SWS,and with 2000s showing most dramatic drying,it implies that in the condition of global warming the aridification over Northeast China would enhance;4) The surface moisture condition is the combined effects of land surface process and climate change;its prediction requires the thorough understanding of surface water budget.