利用静止气象卫星监测浙江海上大雾

卫星遥感是监测大雾的重要手段,利用静止气象卫星监测海上大雾,可以得到时间分辨率比极轨卫星更高、空间覆盖比地面观测更连续的大雾产品。采用分级判识太阳高度角阈值和归一化大雾指数(NDFI)的方法,反演了2008年至今浙江海雾的逐时分布,并将静止卫星(MTSAT)遥感大雾监测结果与近5年地面大雾观测和2013年春季能见度自动观测记录作对比,结果显示遥感反演的总体精度分别为68.4%和69.6%,且空间分布上与地面观测相吻合。表明该方法可突出雾与其他地物的差异,且判识方法简单、实用性强、准确率较高;实时监测浙江海上大雾是可行的,具有良好的业务应用前景。不同时段正确率的验证结果显示,该方法更适用于海雾频发的冬春季以及白天的监测。

Monitoring Sea Fog of Zhejiang from Geostationary Meteorological Satellite Data

Remote sensing is an important method to monitor sea fog.In order to get the sea fog products with the time resolution higher than those from polar orbit satellites and the space coverage larger than those from ground based measurements,the data from Japanese MTSAT geostationary satellite were used to retrieve the sea fog in Zhejiang province and its adjacent sea area.Normalized Differential Fog Index(NDFI) and classified of the solar elevation angle were applied to extract the sea fog from cloud and other feature types since 2008,and the sea fog results of remote sensing were compared to the manual observation about nearly five years and visibility automatic observation hourly in the spring of 2013.The results showed that the overall accuracy of remote sensing retrieved were 68.4% and 69.6%,and the spatial distribution was similar as the observation.It is feasible to monitor the sea fog using the geostationary meteorological satellite at real time,and has a good application prospect.Hit percent of the different time indicated that,the sea fog method by remote sensing was more suitable for winter and spring as well as daytime.