青藏高原融冻过程中能量和水分循环的模拟研究  

A Simulation of the Energy and Water Cycles in Seasonal Freezing-Thawing Process on the Tibetan Plateau

作　　者：彭雯[1] 高艳红[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所陆面过程与气候变化重点实验室,甘肃兰州730000

出　　处：《冰川冻土》2011年第2期364-373,共10页Journal of Glaciology and Geocryology

基　　金：国家重点基础研究发展计划(973计划)项目(2005CB422003);中国科学院知识创新工程重要方向项目(KZCX2-YW-328)资助

摘　　要：采用与先进陆面模式耦合的区域气候模式WRF V3.1,利用NCEP/DOE再分析资料作为驱动场,对青藏高原东北部1998年5-7月进行模拟.首先,对模拟区降水、感热和潜热通量的空间分布进行了检验,结果表明WRF模式能够合理且较好的模拟出高原东北部降水、感热和潜热通量的空间分布状况.通过对融冻过程中土壤温、湿度及水文要素的分析发现,融冻过程首先影响土壤温、湿度,进而影响地气间能量和水分交换,最终影响整个局地水循环过程.冻结时,感热通量占主要地位,陆地系统净水分输入主要转化为蒸发和径流,水分盈余变化基本为零;融化后,潜热通量占主要地位,随着降水量增大和土壤下渗能力的增强,陆地系统水分盈余迅速增大,径流相应减小.但不同下垫面上略有差别,草地、灌木丛、稀疏植被和苔原上水循环要素的变化趋势与区域平均基本类似,水分盈余变化呈增大的趋势,沿水体周围草地的水分盈余随时间减小,水体上的水循环活动最为剧烈,水分盈余最为丰富.Using NCEP/DOE reanalysis data as driving data,a simulation from May to July,1998 was conducted for the northeastern Tibetan Plateau by using the regional climate model WRFV3.1 coupled with advanced land surface model.Comparison between the simulated and the intensified GAME analysis data show that the WRF model can well reproduce the features of temporal and spatial distributions of precipitation,sensible heat flux and latent heat flux and give a reasonable and better simulation over the northeast plateau.Analyses of soil temperature,soil moisture and hydrological elements during the permafrost thawing process show that soil thawing process first impacts soil temperature and soil moisture,thereby affects energy and water exchanges within earth-atmosphere system,and ultimately affects the whole local water cycle process.Before the thawing process,the sensible heat flux dominates the heat balance;the net water input to the land system mainly turns into runoff and evaporation,without terrestrial water storage change;after the thawing process,latent heat flux and terrestrial water storage change increase.But there are slight differences between different underlying surfaces.Variations of water cycle elements over grassland,shrubland,barren land and tundra are basically similar with the regional average.

关 键 词：青藏高原 融冻过程 水循环 下垫面 

分 类 号：P642.14[天文地球—工程地质学]