青藏高原地气交换特征参数的区域化

The soil thermal conductive equation and soil thermal conductive equation with thermal convection term contained were solved analytically resulting formulas to compute apparent soil thermal diffusivity and soil thermal diffusivity directly at first. Based on the observation data from soil moisture and temperature measurement system (SMTMS) sites during GAME/Tibet over Tibet Plateau.This study demonstrates that the apparent soil thermal diffusivity in this area over Tibetan Plateau is between 0.30-0.98×10-6 m2s-1 in the upper layer (from depth 0.04 m to 0.20 m) where the soil thermal diffusivity should be between 0.15 and 0.72 ×10-6 m2s-1..SiB2 (Simple Biosphere model version 2) is adopted to simulate surface energy budget in offline mode with certain atmospheric forcing values measured in near surface observations taken over in Tibetan short grass prairie as part of the GAME/Tibet (GEWEX Asian Monsoon.Experiment/Tibet) experiment. The simulated net radiation, latent heat.flux and soil heat flux are shown to be basically in good agreement with.observations ， their relative error are 8% (underestimated), 6%.(underestimated), and 3% (underestimated)， respectively, in meantime,SiB2 overestimates sensible heat flux 40%.Based on the former researches of the sensible heat flux, the derivation processes of the surface heat flux equation were examined in.detail. Using GAME/Tibet data measured during June 6 ~ September 13,1998,.the counter-gradient heat transference within near surface layer was.validated. Also, two methods to calculate sensible heat flux were compared,likewise, the calculation scheme of sensible heat flux in Simply Biosphere model 2 (SiB2) with relevant simulation were investigated. The results show that (1). Energy imbalance is a common phenomenon by using the.traditional closure scheme on the heterogeneous underlying surface.because the measured ensemble heat fluxes by eddy correlation contains.the effect of nonlocal parcel movements; a heterogeneous underlying.surface is crucial for energy imbalance. (2). Nonlocal parcel movementdeserves more attention in heat flux study in the future.

在现有青藏高原边界层热动力研究基础上，利用高原常规观测、考察试验以及自动站观测资料，结合简化生物圈模式和最新卫星遥感资料，着重分析高原不同下垫面特征地区的陆面过程，深入研究和发展由多点到面的“区域化”技术和方法，初步提示青藏高原地区地气交换特征，研究成果可望改善区域模式的参数化方案。