# The Customized Automatic Processing Framework for HY-2A Satellite Marine Advanced Products
## 2 Products and Related Work
### Related Work and Problems  
Over the past decades, with the advances of the Earth Observation (EO) technology, remote sensing data have accumulated to a considerable degree. In order to ease and increase the use of these remote sensing data, many data agencies set up their own data service platforms, such as the Multi-Satellites Data Service system operated by the Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences (RADI) [18; 19], the Land Observation Satellites Data Service platform from the China Centre for Resources Satellite Data and Application [20], the Data Service platform from Remote Sensing Technology Center of Japan [21], the GISTDA Data Service system from Geo-Informatics and Space Technology Development Agency of Thailand [22], and the Earth Online platform from the European Space Agency [23]. These systems and platforms provide catalogue access and data distribution services for standard remote sensing products, which are similar to the HY-2A ground application system. On the other hand, because of the new open data policy adopted by the United States Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA) in 2008, remote sensing data usage exploded [24]. Afterwards, ESA adopted the similar strategies. Today, more than 250,000 images are downloaded each month through two online platforms, the USGS Global Visualization Viewer (GloVis) [25] and the Earth Explorer system [26]. In addition, there is an obvious shift of service model from \"provider push\" to \"user pull\", which can facilitate scientists and the public to access remote sensing data [27; 28]. Therefore, many data providers have developed a series of online tools for users to visualize and analyze the data [29; 30; 31]. In the marine field, the Giovanni data service platform [32] provides an integrated interface for users to plot high-level marine products and download the datasets directly. The Sentinels Scientific Data Hub provides complete, free and open access to Sentinel-series products [33]. The AVISO data service platform (Archiving, Validation and Interpretation of Satellite Oceanographic data) [34] and the CopernicusMarine Service platform [35] also provide a reference portal for users to access, read and visualize the datasets derived from different sensors. While the existing ground application system supports the routine business of the HY-2A satellite mission, there are some problems exposed in practice because of the unique characteristics of ocean remote sensing data. At first, the archived data are limited to the satellite geometry defined by the standard pass, which is a long north-south track covering a large area. However, especially for the level-2 and level-3 products, users always want to extract an area of interest (AOI), which may be larger or smaller than a standard satellite pass. The existing system does not provide corresponding tools for users to effectively obtain their desired results. In addition, the existing ground application system uses different data formats to store data from the HY-2A satellite. For example, the products of the scatterometer, the scanning microwave radiometer and the calibration microwave radiometer are stored in the HDF5 format developed by the Hierarchical Data Format (HDF) group [36], and the products of the radar altimeter are stored in the network Common Data Form (NetCDF) format developed by the University Corporation for Atmospheric Research (UCAR) [37]. These formats can be used to store and organize large volumes of numeric data into a multi-dimensional structure that needs specialized tools to deal with, such as the HDF Viewer [38]. However, because these tools only provide a limited number of functions to browse and edit the data, it is difficult for users to compare, analyze and visualize data, precluding the usage of HY-2A satellite data. Moreover, the existing processing procedures in the processing subsystem are designed as a fixed number of steps, which is not easily modified.