气象灾害事件的数学形态学特征及空间表现

The Morphological Characteristic and Spatial Behavior of the Meteorological Disaster Event

几何面特征是气象灾害的主要空间形态表现,气象要素值的同化结果、下垫面地表类型、人口和财产的聚集特征组合在灾害特征面上的分布情况呈现显著空间差异及分布不均衡。利用空间分析和数学形态学方法,依据城市地区复杂下垫面所表现的地表土地覆盖类型,生成数字化动态卷积模板,对建立在气象要素分布图上的图谱化网格进行动态膨胀和腐蚀操作,计算结果可图形化表示为气象灾害在城市空间面上的影响图谱,并以此作为气象灾害在城市地区造成影响的空间评估结果。针对北京1999年7月22日的高温灾害性天气的个例研究结果表明,靠近或包含"水体"和"绿地"的空间网格区域大多被执行了腐蚀操作,而建筑用地、道路、水泥地面等分布较集中区域的空间网格,则被执行了膨胀操作。因此,采用数学形态学的"面状灾害事件"空间形态特征的演算对表现灾害自然强度及评估多致灾因子下灾害的真实影响情况是非常有效的。

The surface formed by the influence of the meteorological disasters is no more than a polygon in its geometry shape. And the assimilatory meteorological elements, the character of the underlying surface, the habitat and accumulative assets of human beings are all combined on the characteristic influencing dimension of disaster, so that the condition indicates significant difference on the distribution and space background. However, the spatial analysis and the method of morphology to initialize the digitized dynamical convolution operator are generally implemented, according to the multi-types of land use and the land cover represented by the complexity of underlying surface on the urban area. Supported by the combined GIS and the morphology technique, the gridded atlas of the meteorological map is handled by the operation of erosion or dilation. Moreover, with the dynamical erosion and dilation operation to the grid map derived from the map containing the contour lines of these meteorological elements, such as the temperature, the precipitation, the humidity, and any of those observations when the disasters occur, the gridded atlas for the urban area influenced by the disaster could be set up, it would be a good way to evaluate the meteorological disasters. The research on the high temperature event occurred on July 22,1999 is carried out as a case study, and it shows that the grids which near or contain the water or green land have been applied with the erosion operation. On the contrary, the grids which are mainly made up of buildings, roads, or cement surfaces are applied with the dilation. The conclusion drawn by the research is conformity with the characteristic of the land surface processed in the urbanized underlying surface, and even the responding behavior is extremely similar. The effectiveness of the case study is very good by applying the spatial evaluating model, and the outcome by the form of atlas is consistent with the actual situation influenced by the disaster. It is also demonstrated that the disaster evaluation with the morphological method is easy to operate, and has the ability to deal with the multi-factors that bring about the loss of disaster, by which the characteristic of the distribution is embodied.