The Application of Monitoring Sea Fog in Taiwan Strait Using MODIS Remote Sensing Data

The sea fog is a frequent severe weather phenomenon, there are many advantages in monitoring the temporal and spatial change of sea fog using remote sensing technology. The visible light channel data and infrared channel data of new MODIS sensors are used to identify and monitor sea fog in Taiwan Strait. Spectrum radiation characteristics of MODIS data on various earth surface, such as ocean, middle-high-level cloud, low-level cloud and sea fog are analyzed, the results show that there are notable spectrum radiation characteristics differences between the sea fog, low-level cloud and ocean, middle-high-level cloud in the Taiwan Strait region.There are also notable spectrum radiation characteristics distinguish in some channels of visible light and middle infrared bands between sea fog and low-level cloud. On the basis of results, the MODIS channels which are sensitive to sea fog are chosen, and the sea fog remote sensing monitoring model in Taiwan Strait region is established by using compositive method, meanwhile the channels combination and digital monitoring indexes which are fit for the sea fog in Taiwan Strait region are validated.The sea fog events in Taiwan Strait region during 2004-2007 are monitored by using the model which has been established, and the sea fog monitoring results are verified and analyzed using the visibility data measured in five meteorological observing stations in Fujian coastal region.The results show that the veracity of sea fog monitoring model is 83.3 % in the mass, and the monitoring model veracity of strong sea fog is better than that of weak sea fog. The monitoring model veracity of night sea fog is relatively low because there are fewer remote sensing channels in the night on MODIS. After the inconsistent samples between remote sensing monitoring and meteorological observing are analyzed, the result shows that the existence of multi-layer cloud has notable influence to the veracity of sea fog. Research result shows:In the view of the sea fog monitoring results which are verified and analyzed between meteorological observing and remote sensing monitoring, the sea fog remote sensing monitoring model in Taiwan Strait region which is established using MODIS data can reasonably describe the distribution status of sea fog, and can dynamically monitor the distribution and developing process of sea fog, the model is very suitable to apply in the future operational work. But because the fog and cloud remote sensing monitoring is very complex, the variety of digital monitoring indexes of sea fog must be noticed in the practical operational work.