Research And Application Of Red Tide Monitozring Method Based On MODIS Images

Qinhuangdao city is located in the center of the bohai sea region and is one of the key development areas of Marine economy in China.In recent years,the frequent occurrence of red tide in Qinhuangdao sea area has damaged the marine ecological environment,affected the local tourism,aquatic resources,and fishery benefits;even the occurrence of toxic red tide has posed a threat to human health and safety.Therefore,the effective monitoring of red tide is of great significance to the economic development of the region.In this paper,the MODIS remote sensing image is used to study and apply the red tide monitoring method.The specific contents are as follows:Firstly,the red tide,qinhuangdao sea area and the red tide situation in recent years are summarized,and the research status and development trend of red tide monitoring are analyzed.Secondly,the processing theory of MODIS remote sensing image is introduced,including satellite ocean remote sensing,water color satellite,MODIS data and ENVI software.Thirdly,according to the June 24,2009 qinhuangdao ocean environment quality bulletin shows the red tide in the data information,on MODIS image using ENVI software to calibrate the geometric correction,and,solar zenith Angle correction,image cropping,fusion,etc,on the basis of pretreatment,using chlorophyll extraction algorithm,single band ratio method,multiband difference ratio method,decision tree classification,the extraction of red tide area in qinhuangdao area respectively,and has carried on the comparative analysis of several kinds of red tide monitoring method,the analysis results show that the red tide monitoring method based on decision tree classification can accurately separate the water and land,Is the most suitable for qinhuangdao sea area red tide monitoring.Last,the red tide monitoring method based on decision tree classification was used to select some MODIS images of qinhuangdao sea area from late June to mid-july 2009 to monitor the occurrence and change of red tide in qinhuangdao sea area,and analyze the factors affecting the occurrence and development of red tide according to the meteorological data.The red tide monitoring method based on MODIS image has good practicability and maneuverability to qinhuangdao sea area,and can provide beneficial services for the monitoring of red tide disaster in qinhuangdao coastal sea area.