HY-1C/D海洋水色卫星产品体系及其典型应用

Products of HY-1C/D ocean color satellites and their typical applications

海洋一号C星(HY-1C)和海洋一号D星(HY-1D)是中国首次对地观测组网的海洋水色业务化应用卫星,其上搭载了海洋水色水温扫描仪COCTS (Chinese Ocean Color and Temperature Scanner)、海岸带成像仪CZI(Coastal Zone Imager)、紫外成像仪UVI (Ultra-Violet Imager)、星上定标光谱仪SCS (Satellite-based Calibration Spectrometer)和船舶自动识别系统AIS (Automatic Identification System),实现了全球海洋水色要素每天2次、海表温度每天4次的全球覆盖观测,中国近海及海岸带区域每3天2次的50 m高分辨率观测。本文介绍了HY-1C/D卫星及其载荷性能、产品处理流程、产品分级与分发等相关信息,HY-1C/D卫星产品体系完整且数据产品处理与分发高效。同时阐述了HY-1C/D卫星的叶绿素a浓度估算和海表温度反演产品,以及HY-1C/D卫星数据在浒苔绿潮、海冰/极冰、近海养殖、内陆水体和台风云图等方面的典型监测应用且具有较好的产品质量、在海洋与海岸带环境监测中具有较高的应用价值。

The HY-1C and HY-1D satellites are the first operational ocean color constellation in China. HY-1C and HY-1D was launched in September 7, 2018 and Jun 11, 2020, respectively. Chinese Ocean Color and Temperature Scanner(COCTS), Coastal Zone Imager(CZI),Ultra-Violet Imager(UVI), Satellite-based Calibration Spectrometer(SCS) and Automatic Identification System(AIS) are the key payloads onboard HY-1C and HY-1D. The HY-1C/D constellation has been detecting the global ocean color twice and sea surface temperature(SST)four times every day, and high-resolution(50m) China’s coastal zone and offshore environments twice every three days.In this article, the HY-1C/D satellites and the specifications of the payloads, flow-process, product levels and distribution of data products are introduced. The overpass times are 10:30 am±30 min and 1:30 pm±30 min of local time at the descending node for HY-1C and ascending node for HY-1D, respectively. The HY-1C/D satellites complete processing chains for generating raw data, radiances, ocean color and Sea Surface Temperature(SST) from the payloads by Geo-location, radiometric and atmospheric correction, geophysical parameters retrieval, data gridding and merging. There are different data products associated with the five levels of processing(Level 0 to Level 4). Data products of Level-1(radiances), 2(ocean color parameters and SST), 3(gridded products) and 4(merged gridded products) are available from the China Ocean Satellite Data Service Center to the general public for free. The HY-1C/D satellites product structure system is complete and data product processing and distribution are efficient.The typical products of Chlorophyll-a concentration and SST, the applications on floating green tides algae Ulva prolifera, sea ice,offshore aquaculture, inland water and tropical cyclones are also presented in this article. Maps of global daily gridded chlorophyll-a concentration and SST(L3A products) from COCTS onboard the HY-1C and HY-1D are presented to show their temporal and spatial coverage. The CZI remote sensing images have being used to extract the distribution location and area of offshore green tide, sea ice and offshore aquaculture facilities. The process of ice shelf falling off and drifting around Antarctic continent has been monitored by using a long time series CZI remote sensing images. In addition to offshore and coastal environmental monitoring applications, HY-1C/D remote sensing data products have also been applied in inland water algal bloom, typhoon cloud map and its moving path monitoring. The typical products and application shown in this article indicates that the sensors and the data products of HY-1C/D have high quality and great application potential in marine and coastal environmental monitoring.The planned future satellites including the next generation of Chinese ocean color satellites and geostationary coastal zone and ocean environment monitoring satellite and their key specifications are briefly introduced. The new generation satellites with more spectral channels, broader spectrum range, and higher temporal and spatial resolution will have greater application potential in monitoring of ocean color and coastal zone ecology, resources and environment.