利用遥感综合分析西风引导气流与地形对沙尘运移路径的影响

Impact of Air Current Arose by West Wind and Terrain on Sand-Dust Storm Movement Analyzed with Remote Sensing Technology

沙尘暴的发生受大气环流、地表状况、降雨的影响,还受到局部地区地形的影响。一次规模较大的沙尘暴过程,沙尘可以从蒙古国和我国西部沙源地输送到我国东部、韩国、日本乃至夏威夷、美国西海岸。中日亚洲沙尘暴ADEC项目对亚洲沙尘暴的起沙、传输和降落的运行机制已经作了深入的研究,并建立了亚洲沙尘暴的数值模拟系统。本文以影响北京地区的沙尘暴事件为例,利用遥感技术,综合DEM地形数据和地面实测数据分析西风引导气流和地形对沙尘运移路径影响,将MODIS影像数据和DEM地形数据以及地面观测站点实测数据相结合,进行综合分析,结果表明在一次沙尘暴过程中,沙尘在运移过程中的运移路径明显地受到西风引导气流、沙尘粒子自然沉降规律以及局部地形的影响,要预防(减少)北京地区的沙尘暴仅仅作好北京地区的生态环境建设是不够的,加强北京周边地区,尤其是张家口地区、官厅水库库区及库区周围地区的生态环境建设尤为重要。

The forming of sand-dust storm depends on atmospheric circumfluence, underlying surface status and rainfall as well as local terrain. The sand-dusts in the processing of a strong storm can be transported from the source areas in Mongolia and western China to eastern China, Korea, Japan and even to Hawaii, the western coast of America. A five-year experiment to investigate the impact of aeolian dust on climate (ADEC) started in April 2000. The aim of the China-Japanse cooperative project is to measure the degree of radiation forced by aeolian dust particles. The studying contents comprise using the GCM-scale sand-dust model to evaluate the sand-dust supplication of storm to atmosphere, analyzing its three-dimensional distribution in atmosphere, calculating the amount of dust deposited on ground surface and its direct forcing effect on radiation. For this purpose, parameterization of wind erosion process and sand-dust flux from the atmospheric boundary layer (ABL) to the free atmosphere is an important step. So, direct observation to wind erosion processes and characterization to sand-dust are required. In situ observation of the wind erosion process using automatic weather stations (AWS) is set up at seven sites around the Tarim basin and Dunhuang. At the first phase, the ADEC project researched the run mechanism of the emission, transportation and deposition of dust storm. And an integrated wind erosion modeling system was built. At the second phase, the impact that the different scale terrain on the emission of dust storm and trajectory of dust transportation is to be researched. In this paper, through analyzing the dust storm happen in Beijing region, using the remote sensing technology, synthetically analyzing the DEM data and in situ measurement data, the impact of air current arose by west wind and terrain on the dust trajectory are research. The outcome showed that air current arose by west wind and the local terrain impact on the dust trajectory evidently. In order to defending or reducing the dust storm in Beijing region, it is not enough to only strength the entironment building in Beijing region. It is also necessary to strength the entironment building of the Zhangjiakou region, Guanting reservoir and its around region.