利用遥感手段判识沙尘暴的一种新方法——以内蒙古地区为例

NEW METHOD TO IDENTIFY SAND AND DUST STORM BY USING REMOTE SENSING TECHNIQUE——WITH INNER MONGOLIA AUTONOMOUS REGION AS EXAMPLE

利用比辐射率的特征，并根据热辐射理论进行沙尘暴遥感监测是一种全新的研究手段．本文发现，沙尘发生时地表的主要物质沙尘、地面和云的物质性质不同，并且沙尘强度不同时图像像元上的地面和沙尘的比例不同。从而导致像元物质的性质有差别，地物比辐射率不相同．通过理论推导和试验研究得出：云区、地面、弱沙尘和强沙尘区的ε29与ε31接近程度不同，且ε31在0～1整个区间上变化时，ε29的大小顺序永远是云〉强沙〉弱沙〉地面，并在此基础上建立了一个稳定判识沙尘强度的沙尘指数（DSI）模型．经过多次沙尘暴的实例验证，结果表明，该模型能够较精确地监测沙尘发生的范围和强度．

The object emissivity characteristics and the theory of heat radiation were studied to detect sand dust storm by remote sensing technique. The results show that the material nature of sand dust, ground surface and clouds is different when the sand dust happens. The ratio between the ground and sand dust in pixel images is different when the strength of sand dust changes. And these differences lead to the variations of material nature in pixels and object emissivity. At last, by a combination of theoretical and experimental researches, it was found that the degree of approach between ε29 and ε31 was different among cloud area, ground surface, weak sand dust and strong sand dust areas. And in a whole range of 0 - 1 of ε31, the order of ε29 is cloud 〉 strong sand dust 〉 weak sand dust 〉 ground surface. According to the results of the above, it was established a stable sand dust index （DSI） model to identify the sand dust strength . And the model can more accu- rately detect the range and intensity of sand dust after several rounds of sand dust examples.