基于MODIS影像的陆地辐射雾微物理参数反演及动态变化分析

Retrieval of Fog Microphysical Parameters and Analysis of Change Condition Based on MODIS Sequence Images about Land Radiation Fog in the Daytime

作为一种常见的气象灾害,雾灾严重的影响了人们交通出行等日常生活。基于遥感影像反演的雾微物理参数可在一定程度反映雾灾的发展状况和严重程度,进而对大雾进行有效的监测和预测。本文选取发生于华北地区2007年11月24日13时10分的陆地辐射雾MODIS影像作为试验数据,在大雾生消机理和遥感影像信息提取基础上,构建了大雾路径辐射模型和微物理参数反演算法,成功反演出能见度、含水量、有效粒子半径3个微物理参数,并在湖北省气象局提供的地面观测数据基础上对能见度进行了地面数据验证,得到两者的相关系数为0.9366,地面数据与反演结果相关性较大,数值误差较小,说明反演方法具有可行性。本文进一步应用该模型对发生于华北地区2007年11月21日至11月26日的一次陆地辐射雾MODIS时间序列影像反演微物理参数并进行动态变化分析,总结出大雾具有爆发性产生和重复阶段性发展的特点,能见度主要受大气辐射和水汽供给的影响,其值在50~130 m之间变化,和平均含水量、有效粒子半径成反比例关系,共同反映出雾灾的严重程度和发展阶段。

As a common meteorological disasters, fog disaster seriously affected people in the daily life such as transportation. To some extent, based on the inversion of remote sensing image can reflect the state of development and level of damage, then contributes to effectively forecast and prediction. This paper chooses the MODIS imagines about land radiation fog which happened at 13 ： 10 on November 24th 2007 in North China area as the experimental data, establishing the path model of fog radiative transfer model and fog microphysicai parameters algorithm based on the fog appear mechanism and fog information extraction on images, inverting the result of 3 microphysical parameters which called visibility, liquid water content, effective particle radius, then verify the result from land ob- serve data which are offered by HUBEI meteorological administration. At last correlation coefficient between the two parameters is o. 9366, which reflect the big correlation and small error, indicating the method of inversion is feasible. This paper continue to use this method of inversion to analysis the dynamic changing condition based on the result about microphysical parameters which come from the land radiation fog images between November 21th and November 26th in 2007 in North China area, summarizing that the fog disas- ter has the feature of explosive happen and repeated developing stage, visibility is mainly affected by atmospheric radiation and the in- fluence of water vapor supply, the value change from 50 to 130m, it has inverse relation to liquid water content and effective particle radius, all of them get together to reflect the damaging level and developin~ sta^e of fo~ disaster.