A Multi-satelite Service System To Monitor Ulva Prolifera Blooms And Their Marine Environment Off Qingdao, China

A large-scale Ulva prolifera bloom occurred in coastal waters off Qingdao, China between May and July 2008. The bloom posed a significant threat to the upcoming Olympic Sailing Competition, and received wide national and international attention. Studies have shown that the satellite remote sensing could synchronously and rapidly monitor Ulva prolifera in large-scale range.Much needed is a system to provide timely information of Ulva prolifera occurrence and development in future events, which is critical to help make management and mitigation decisions. Based on multi-satellite data collected by national and international instruments such as MODIS, a preliminary monitoring and service system has been established at the Ocean Remote Sensing Institute (ORSI) of the Ocean University of China. The system has two main objectives: One is to provide technology support and information service to local government agencies for effective monitoring of Ulva prolifera bloom events; Two is to offer a platform to facilitate research on marine ecology and marine remote sensing of Ulva prolifera. The system provides several types of Ulva prolifera data products, including Red-Green-Blue (RGB) true color composite image, normalized difference vegetation index (NDVI) image, floating algae index (FAI) image and Ulva prolifera coverage area and range image. The system also provides data products of the general marine environment such as Sea Surface Temperature (SST), chlorophyll concentration (Chla), Photosynthetic Active Radiation (PAR), Sea Surface Wind (SSW), and Sea Surface Current (SSC).The system includes three major functions: 1) download satellite data, 2) process satellite data, and 3) distribute data products. Satellite data, mainly from the MODIS measurements, were downloaded automatically every day from the data service centers. These low-level data were then processed using computer software provided by the data service centers and developed in house. The data product distribution and information management function is based on the Browser/Sever (B/S) Architecture Technology use the Model-View-Controller (MVC) model. Java 2 Platform Enterprise Edition (J2EE) was used to implement the system, which is divided into a client layer, a presentation layer, a business layer, and a persistent layer and a data layer in logic. The Struts2 framework, the Google Map framework and Hibernate framework were used to construct the data product distribution and information management function in technology.The experimental monitoring system, namely ORSIFAI, has been put in use in the summer of 2009 and 2010 to provide data and information to researchers and to Qingdao Municipal Science and Technology Agency. The system can be accessed at http://www.station.orsi.ouc.edu.cn:8080/algae/.