HY 1C, 1D

HY 1C [CAST]

HY 1 (Haiyang = Ocean) is a series of Chinese operational ocean remote sensing satellites based on the CAST968 bus.

The 442 kg box-shaped satellite is three-axis-stabilized and Earth-oriented, with the twin solar wings oriented to the sun. It incorporates an integrated on-board operation management system and has a design life of five years. Its payloads include a 10-band ocean color scanner with a revisit period of 3 days and a 4-band CCD imager with a revisit period of 7 days.

HY-1 can provide real-time observations of China's coastal regions such as the Bohai Sea, the Huanghai Sea, the Donghai Sea, the Naihai Sea and other seacoast regions. Remote sensing data on the rest of the world can be stored in the onboard data storage device for delayed replay.

The main task of HY-1 is to observe sea optical characteristics, chlorophyll concentration, surface temperature, suspended silt charge, soluble organic matter and pollution. It can also be used to observe sea ice, shallow sea terrain, ocean current characteristics and atmospheric aerosol on the sea surface.

Two improved satellites, HY 1C and HY 1D feature an improved coastal scanner with a resolution of 50 m and two new instruments - an ultraviolet imager and a calibration spectrometer. Additionally they carry an AIS system for ship tracking.

Following instruments are on board:

• COCTS (China Ocean Color and Temperature Scanner), the main payload on-board is an optical radiometer to detect ocean color and surface temperature by 8-channel visible and near-infrared bands and 2-channel thermal infrared bands (10.3~11.3 µm and 1.5~12.5 µm). COCTS of HY-1C detects global ocean and land twice a day, provides daily ocean color,land vegetation products as well as daytime SST (Sea Surface Temperature) and NSST.
• CZI (Coastal Zone Imager) is a pushbroom instrument with the objective to monitor vegetation and the coastal zone. Observations are performed in 4 bands in the VIS/NIR region. The pushbroom instrument features 21800 pixels/line on a swath of 950 km, the spatial resolution is 50 m. The CZI (Coastal Zone Imager) is mainly used to obtain real-time image data of the sea-land interaction area for coastal zone monitoring, to understand the distribution of suspended sediment in key estuary harbors, and to conduct real-time marine environmental disaster monitoring and warning including sea ice, red tide, green tide and pollutants.
• UVI (Ultraviolet Imager): The objective is to improve the atmospheric correction accuracy of high turbid water in the near shore.
• SCS (Satellite Calibration Spectrometer): The objective is to provide on-board synchronous calibration for the 8-band COCTS and the 2-band UVI instruments, to monitor the in-orbit radiation stability for COCTS and UVI. The visible, near-infrared spectrum of the payload has the ability to transmit 5nm bandwidth continuous spectral data in the 400~900 nm range and the in-orbit solar calibration ability. The bands of the payload include 2 UV and 8 visible, near-infrared bands of COCTS.
• AIS (Automatic Identification System): The objective is to obtain the ocean ship location and the attribution information and to provide data services for marine right maintenance, marine disaster prevention and mitigation, and marine fishery production activities.