三种经典夜间陆地雾遥感反演方法的适用性对比分析

相较于地面站点观测,卫星可以监测更大范围的夜间雾区分布,目前虽然已存在几种经典的夜间陆地雾遥感反演算法,然而其在我国大范围陆上的适用性尚不清楚。基于葵花8号(Himawari-8)静止气象卫星数据,分别利用双通道差值法、温度差值法及归一化大雾指数法反演了我国2016年1月—2018年12月的夜间陆地雾区,并用地面观测资料以鉴定成功评分、准确率、判识率和误判率为指标参数对雾区反演结果进行验证分析,讨论了三种反演方法的适用性。结果显示:1)三种夜间陆地雾反演方法在秋季和冬季反演效果最好,其中温度差值法的鉴定成功评分高、准确率高、误判率低,反演效果最好,双通道差值法的判识率高、误判率高,反演效果次之,归一化大雾指数法效果最差。2)三种方法对夜间陆地雾的反演在秋季和冬季的最佳适用区域略有不同,但都倾向于在平原和盆地达到最佳效果,如华北平原、长江中下游平原和四川盆地。3)两次雾过程的反演结果显示,温度差值法和双通道差值法对平原地区夜间雾的识别能力均较强,在具体雾过程反演中各有优势。

Applicability comparison of three classical remote sensing retrieval methods for nighttime land fog

Compared with observation by ground meteorological stations,satellite monitoring of nighttime land fog can provide a wider range of fog distribution.However,there is a lack of analysis on the applicability of several classical remote sensing retrieval algorithms for nighttime land fog in China.Based on Himawari-8 satellite data,the method of dual channel difference(DCD),the method of temperature difference(DT),and the method of normalized fog index(NDFI)are used to retrieve the nighttime land fog area in China between January 2016 and December 2018.And the critical success index(CSI),the hit rate(HR),the probability of detection(POD),and the false alarm ratio(FAR)are used as index parameters to verify the retrieval results and discuss the applicability of the three methods based on the ground observation data.The results are shown below.1)The three methods have the best retrieval effect in autumn and winter,among which the DT method performs the best because of its high CSI,high HR,and low FAR.Due to the high POD and high FAR,the effect of DCD method comes second,and the NDFI method performs the worst.2)The optimal regions for the three methods have slight difference in retrieval of nighttime land fog in autumn and winter,but they all tend to achieve the best results in plains and basins,such as the North China Plain,the Middle-Lower Yangtze Plain,and the Sichuan Basin.3)The retrieval results of two fog processes in autumn and winter show the DT method and the DCD method both have strong ability to identify the nighttime fog in plain areas,and they have their own advantages in specific fog process.