农牧交错带陆面过程的数值模拟研究

利用CLM(Common Land Model)模式对我国内蒙古奈曼旗农牧交错带沙漠和农田两种不同典型下垫面的陆面过程进行了数值模拟试验,并与外场试验观测结果进行了对比分析。结果表明:无论是沙漠还是农田试验,CLM都能够较好地模拟其辐射通量和土壤中的热传导特征,CLM的模拟结果能够真实地再现试验期间土壤热传导过程对天气过程的响应。相比而言,模式对沙漠地区长波辐射通量和干燥时期短波辐射通量的模拟结果好于农田,其原因可能是因为农田下垫面植被及土壤特征较沙漠复杂,有着很大的不确定性,造成了农田地表反照率和温度模拟的偏差。而对农田热传导的模拟结果好于沙漠,反映了CLM对含水量较大、持水力较强的农田下垫面的热传导模拟能力较好,而对含水量较小、持水力较弱的沙漠下垫面的热传导模拟能力相对较差。

Numerical Simulation Research of Land Surface Process in the Region between Cropland and Pasture

In this paper,CLM(common land model) is introduced and numerical simulation test is carried out in desert and cropland respectively,and comparing analysis with observational data of corresponding sites is also made in the region between cropland and pasture in naiman of neimeng province in China.The results of this test show that CLM can effectively simulate the characteristics of radiation flux and thermal conduction of soil in both desert and cropland tests.Furthermore,the simulation of CLM can realistically reproduce the response of thermal conduction in soil to weather process which happened during the test period.But in comparing,as for the simulation of longwave radiation flux in whole test period and shortwave radiation flux in dry period,the result of desert test is better than that of the cropland test,because vegetation and soil feature of cropland is more complicated than those of desert,and to specify them exactly is unpractical,which cause the simulative difference of albedo and land surface temperature in cropland test.But for the simulation of thermal conduction,the result of cropland test is better.This indicate that CLM has a better thermal conduction simulating ability to such land surface as cropland which has big water content and is good at maintain water while has a worse ability to those dry land surface as desert.