土地利用/覆盖变化对中国不同季节气温的影响

近几十年中国地区土地利用/覆盖变化(LUCC)较大,在区域气候模拟中尤其需要使用更加准确的土地利用/覆盖数据。基于模式原有的USGS和新开发的LUC90两种土地利用/覆盖资料,利用区域环境集成模拟系统(RIEMS2.0)分别进行连续10a模拟,分析LUCC对中国不同季节气温的影响。结果表明:1)采用LUC90资料后,中国及东北、华北、华南夏季平均气温增加,但只有东北模拟与观测值的偏差减小,且通过显著性检验(P0.01)。中国及东北、华南冬季平均气温增加,并且模拟与观测值的偏差减少。中国及华北和华南对冬季气温年际变率的模拟改善好于夏季。2)土地利用/覆盖变化通过影响潜热通量的变化和净吸收辐射通量的变化来影响不同季节气温的变化。冬季净辐射通量变化对气温变化的贡献较夏季大,而夏季潜热通量变化对气温变化的贡献较冬季大。雨养农田转变森林、草地、灌溉农田过程造成通量变化,其对气温变化的影响也存在不同分区季节的差异。

Impacts of land use/cover change in China on mean temperature

In recent years, Regional land use/cover in China change a lot, and climate simulation need to do more research, especially related to impacts on climate simulation by using new accuracy land cover data sets in region climate model. In this paper, With the original land use / land cover data based on (USGS) and high accuracy land use/cover data (LUC90), Regional Integrated Environmental Model System (RIEMS2.0) were used for 10 consecutive years numerical simulation about impacts on climate, and the analysis was focused on the surface temperature and surface fluxes, testing statistical significance. The results showed that: 1)After using LUC90 data simulation, winter cold bias value compared to observation value in most regions in China was reduced, and different seasons temperature bias of northeast area were reduced, passing the test of significance in the summer(P < 0.01). The annual mean temperature in China, North China and South China in the winter of interannual variability simulation was better than in the summer. 2) Effects of land use change on the distribution of the surface fluxes in different regions and different seasons have different performance, mainly through changes in net radiation and latent heat fluxes to the impact of temperature. We found in the winter contribution of net radiation flux change to mean temperature change was large in summer, and in the summer the latent heat flux change contribution to temperature change was more than in winter. Different land use/cover change process in different regions in different seasons resulted to different effect on the temperature.