基于卫星遥感多源融合的东亚沙尘气溶胶排放模拟研究

The sand and dust storm in East Asia is an severe weather affecting China and even the whole world. The dust aerosol emission is greatly affected by the real-time situation of the surface. At present, due to the lack of timely, accurate and high coverage of surface condition data input, the simulation results of dust aerosol emission have great uncertainty, which has become a major bottleneck affecting the accuracy of dust numerical model prediction results. This project intends to analyze the vegetation index, snow cover and soil moisture, which affect dust aerosol emissions, based on a variety of satellite remote sensing data, and build a dynamic grid for dust numerical model, by quantitatively analyzing the sand-soiling mechanism of each factor. It can make up for the shortcomings of fixed soil type and the insufficient spatial resolution of ground observation data using in the current dust numerical model. Then the results are applied to China's self-developed Asian dust numerical forecasting model (CUACE\Dust) to make a more accurate quantitative assessment of the temporal and spatial distribution and changes of dust aerosol emissions in East Asian. Thus, the prediction accuracy of sand and dust weather can be improved, and the important role of dust aerosols in global climate change can be further studied.

东亚沙尘暴是一种影响我国乃至全球的重要灾害性天气，沙尘气溶胶排放量受到地表实时状况的影响时空变化较大，目前因缺少及时准确、高覆盖率的地表状况资料输入，造成沙尘气溶胶排放模拟结果有很大的不确定性，成为影响沙尘数值模式预报结果准确率的一个重大瓶颈。本项目拟基于多种卫星遥感资料分析影响沙尘排放的植被指数、雪盖和土壤湿度等因子，通过对各个因子影响起沙机制的量化分析，构建用于沙尘数值预报模式的动态网格化沙源地陆表状况时空分布资料的处理方法，弥补目前沙尘数值模式中土壤类型较为固定和地面观测资料空间分辨率不足的缺点。然后将结果应用于我国自主研发的亚洲沙尘数值预报模式（CUACE\Dust）对东亚沙尘气溶胶的排放量的时空分布及变化做出更为准确的定量评估，从而提高沙尘天气的预报准确率，并为进一步研究沙尘气溶胶在全球气候变化中的重要作用提供支撑。

沙尘天气是东亚地区一种常见的灾害性天气，会造成严重的空气污染并危害工农业生产，还会通过改变辐射平衡影响天气系统和气候变化。本项目基于多种卫星遥感资料分析影响沙尘排放的植被指数、雪盖和土壤湿度等因子，通过对各个因子影响起沙机制的量化分析，构建用于沙尘数值模式使用的动态网格化沙源地陆表状况时空分布资料的处理方法，弥补目前沙尘数值模式中土壤类型较为固定和地面观测资料空间分辨率不足的缺点。然后将结果应用于我国自主研发的亚洲沙尘数值预报模式（CUACE\Dust）对东亚沙尘气溶胶的排放量的时空分布及变化做出了准确的定量评估。改进后的沙尘数值模式既能体现极端天气下发生沙尘暴的剧烈程度，又能对下垫面状况变好后沙尘气溶胶排放减少的现象进行更为准确的评估。虽然沙尘数值模式改进后个别沙尘天气过程的沙尘气溶胶排放量增加，但全年总体的沙尘气溶胶排放量是减少的，同时干沉降量也有相同趋势的改变，但湿沉降量却大幅度增加。东亚地区沙尘气溶胶的年均排放量为300.17 Tg·y-1，干沉降量为227.91 Tg·y-1，湿沉降量为18.14 Tg·y-1，总沉降量为227.91 Tg·y-1占排放量的75.93%。新版本模式提高了沙尘天气的预报准确率，其更为精确的沙尘气溶胶排放和干湿沉降结果可在进一步研究沙尘气溶胶在全球气候变化中起到重要作用。