Study On The MODIS Data Used In Remote Sensing Of Ulva Prolifera

A great amount of Ulva prolifera outbreak in the Yellow Sea in summer yearly, since it outbroke during the summer of 2008. It has become an annual marine ecological disaster, caused serious impact on Chinese marine ecological environment. Nowadays, satellite remote sensing had played an important role in monitoring Ulva prolifera. This paper mainly studied Ulva prolifera remote sensing using MODIS data.Firstly, differentiate capabilities of 4 Ulva prolifera indexes were evaluated through 16 MODIS images. The results show that NDVI was the best. HJ—CCD images were added to establish the “index-abundance ” decomposition of mixed pixel model. And, the near real-time HJ-CCD images were used as reference to evaluate the models of 4 Ulva prolifera indexes. The results show that FAI was the best, NDVI the second.Secondly, the distributions of Ulva prolifera from 2008 to 2015 were obtained by processing MODIS images. According to the processed images, the paper analysed how Ulva prolifera developed in the Yellow Sea. Results show that: there are two paths for Ulva prolifera to move northward, first path to the northeast, while the other to the north by west. Correspond to these two ways, there are two landing ways. While Ulva prolofera strips move to the northeast, the main part of Ulva prolifera move close to the offshore of Shandong Peninsula from the open seas. And the landing sequence is from east to the west, the eastern coast affected earlier, the western later. While, the northward situation, landing sequence is from the west to the east along the offshore, and the western coast affected earlier, the eastern later. Meanwhile, eastward Ulva prolifera strips can also be observed, but the scale is much smaller compared to the northward situation. Furthermore, the Ulva prolifera strips lasted a long time until the end of the Ulva prolifera along Subei bank.Lastly, this paper takes advantages of the two MODIS images acquired in a day and maximum correlation coefficient method to get the velocity of Ulva prolifera strips. Then, use the Geography link tool in the ENVI software to validate the results. Result shows that: velocity extracted from the two MODIS images can descript the movement of Ulva prolifera strips relatively accurately.