# The Customized Automatic Processing Framework for HY-2A Satellite Marine Advanced Products
## 1 Introduction  
Marine ecosystems are important for human beings. However, due to the fact that the marine environment is dynamic and covers approximately 70% of the Earth's surface, it is difficult to observe and monitor the global ocean by using traditional means. In contrast, satellite remote sensing possesses some significant advantages. It is an effective and efficient way of observing the ocean all day and in almost all weather conditions. Furthermore, with high-frequency revisit times and long-term service life, it can easily collect the data of dynamic ocean characteristics covering a large area for years. These merits of the technology provide the possibility of further studying, developing and utilizing ocean resources [1]. Since the 1970s, many countries have launched their own ocean satellites to collect information of ocean properties. According to the different electromagnetic spectrums that they use, the onboard sensors can be categorized into two groups: ocean color and temperature instruments, and ocean dynamic environment instruments. The ocean color and temperature instruments usually depend on the visible spectrum to observe the color changes associated with phytoplankton and sediment concentrations within the euphotic depth, and the infrared spectrum to detect the blackbody radiation emitted from the top few micrometers of the water column. For example, the United States launched the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) instrument on the SeaStar satellite, the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on the TERRA and AQUA satellites, and the Visible/Infrared Imager/Radiometer Suite (VIIRS) on the Suomi-NPP (National Polar-orbiting Partnership) satellite. The European Space Agency (ESA) also launched the European Medium Resolution Imaging Septrometer (MERIS) on the ENVISAT satellite(Environment Satellite). Afterwards, the ESA and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) launched the Ocean and Land Colour Instrument (OLCI) on the Sentinel-3A satellite and the Advanced Very High Resolution Infrared Radiometer (AVHRR) on the METOP-series satellites (Meteorological Operational satellite programme). For the ocean dynamic environment instrument, the onboard sensors usually can be a microwave scatterometer, a radar altimeter, a microwave radiometer or synthetic aperture radar. In the long microwave wavelengths, these active and passive observation instruments can use the backscatter of the waves at the sea surface and blackbody radiation naturally emitted from the sea surface to retrieve information on the ocean. For example, the United States and France have the JASON-series satellites (Joint Altimetry Satellite Oceanography Network) to produce sea surface topography data. EUMETSAT has the METOP and the Sentinel series for observations of ocean winds and sea surface temperature. Canada has the RADARSAT synthetic aperture radar satellites. On the other hand, by using the data derived from these sensors, researchers conducted many studies on the remote sensing applications, such as ocean color [2; 3], sea surface temperature [4; 5], and sea surface height [6; 7]. China has its own plan for building ocean satellites dedicated to ocean color and temperature, ocean dynamic environment and ocean surveillance, and has launched three satellites called HY-1A, HY-1B and HY-2A. The first ocean satellite, which is HY-1A, was launched in 2002. It was used to detect ocean color and temperature. The satellite carried two sensors. The first is an ocean color scanner with 10 bands and the second is a coastal zone color scanner with four bands. The major mission of the satellite is to detect ocean color environmental properties, including chlorophyll concentration, suspended sediment content, dissolved organic matter, sea surface temperature, and shallow water depth and topography [8]. HY-1A operated for more than two years. Subsequently, HY-1B was launched in 2007. This satellite was a substitute for HY-1A and its accuracy was improved.