中国农田下垫面变化对气候影响的模拟研究
Simulative study of the impact of the cropland change on the regional climate over China
-
摘要: 使用同期的美国国家环境预报中心/能源部(NCEP/DOE)再分析资料驱动区域气候耦合模式AVIM-RIEMS2.0,从遥感卫星图像资料中获取3期中国土地利用/覆盖数据中的农田植被类型,将其分别引入到AVIM-RIEMS2.0模式进行积分,研究中国农田下垫面变化对东亚区域气候的影响。结果表明:中国农田变化对气候影响具有冬季弱、夏季强的季节性变化,夏季气温和降水的差异在一些地区通过了95%的显著性检验;20世纪80年代农田扩张,林地、草地为主的植被类型转化为农田,植被变化区域的叶面积指数降低,反照率升高,且通过了95%的显著性检验,使得中国东部地区的气温由南到北呈现增加—减少—增加—减少的相间变化趋势,而降水的变化趋势大体相反;20世纪90年代农田面积减少,除东北地区外,农田变化引起的植被变化与80年代基本相反,叶面积指数变化、反照率以及由此导致的气候各要素也呈现大体相反的变化趋势;不同时期农田变化引起的植被类型转化的差异,使850 hPa风场变化趋势基本相反,可能是导致气温和降水变化趋势差异的主要原因之一。Abstract: The cropland types in the three-period land use and land cover (LULC) data from the remote sensing satellite images were incorporated into the coupled regional climate model AVIM-RIEMS2.0. The NCEP/DOE reanalysis data in the same period was used to drive the AVIM-RIEMS2.0. The research investigated the impact of the cropland change on the regional climate over China. The results show that the impact of cropland change on climate is stronger in summer in contrast with winter over China. The temperature and rainfall difference between the observation and simulation passes the significance test at the 95% confidence level in some areas in the summer. Cropland expansion results from the conversion from woodland or grassland to cropland in the 1980s, with the leaf area index decreasing and surface albedo increasing, both passing the 95% confidence level in the region of vegetation change, leading the temperature to an interval change of "increase-decrease-increase-decrease" from south to north in Eastern China. However, the rainfall changes show a generally opposite trend. The cropland area decreases in the 1990s except for Northeast China. Vegetation changes due to cropland change are opposite to those the 1980s, and the opposite changes also exist in the leaf area index, surface albedo and the climatic variables. The different conversions of vegetation types in the cropland change make the 850 hPa mean wind field appear the general reverse change, which is one of the main reasons leading to the different change of temperature and rainfall.