基于中国植被数据的陆面覆盖及其对陆面过程模拟的影响

本文基于中国1:100万植被图、马里兰大学AVHRR森林覆盖资料和中国753个气象站点40年的降水气温资料, 发展了一套用于气候模拟的中国陆面覆盖资料(Chinese land cover derived from vegetation map, 简称CLCV)。该套资料与CLM(Community Land Model)原来所用的MODIS (Moderate Resolution Imaging Spectroradiometer) 陆面覆盖资料相比有较大不同: 其中裸土比例减少了14.5%, 森林、灌木、草原和农作物比例分别增加了3.3%、4.8%、4.4%和0.3%, 冰川、湖泊和湿地比例分别增加了0.4%、0.8%和0.6%。将CLCV和MODIS资料分别与全国土地资源概查汇总结果分省统计资料和基于中国1 km土地利用图的土地利用资料比较表明, CLCV与两者较为接近。最后, 利用CLM模式分别采用CLCV与MODIS陆面覆盖资料在中国区域内进行数值模拟, 结果显示, 使用CLCV资料所模拟的蒸散增加了约7.7 mm/a; 地表反照率、 感热和径流分别减小了约0.7%、 0.3 W/m2和7.6 mm/a; 与MODIS卫星反演地表反照率和GRDC (Global Runoff Data Centre) 径流资料比较表明, 利用CLCV资料所模拟的地表反照率有一定改进, 并能基本模拟出径流分布趋势。

A Land Cover Dataset Based on Chinese Vegetation Data and Its Impact on Land Surface Simulations

The authors develop a new land cover dataset (CLCV) based on the 1:1000000 Vegetation Atlas of China, the AVHRR (Advanced Very High Resolution Radiometer) Continuous Fields Tree Cover of UMD (University of Maryland), and the precipitation and temperature data of 753 weather stations in China, and investigate its effects on the energy and water balance over continental China. Compared to the MODIS data, the CLCV data have a decrease of 14.5% in bare soil fraction, which is realized through increased tree, shrub, grass, crop, glacier, lake, and wet land at 3.3%, 4.8%, 4.4%, 0.3%, 0.4%, 0.8%, and 0.6%, respectively. Compared to the statistic data and land use data, the CLCV data is much closer to them than the MODIS data. The simulation results show that the simulated evapotranspiration increases about 7.7 mm/a, and the simulated surface albedo, heat flux, and runoff decrease about 0.7%, 0.3 W/m2, and 7.6 mm/a, respectively; compared to the MODIS albedo data and the GRDC runoff data, the simulated surface albedo and runoff by the CLM with CLCV data get much closer to the observed data than that with the MODIS data.