HY-2 (HaiYang means 'ocean' in Chinese) is a marine remote sensing satellite series planned by China (HY-2A to HY-2G).

HY-2 belongs to a serie of ocean-oriented satellites:

• HY-1A and HY-1B (respectively launched on May, 2002 and April, 2007) are designed to measure the ocean color and temperature with the visible and infrared sensor;
• HY-2 is focused on the marine dynamic environment;
• HY-3 will combine visible/infrared and microwave sensors.

The objective of HY-2 series is to monitor the dynamic ocean environment with microwave sensors to detect sea surface wind field, sea surface height and sea surface temperature. It includes an altimeter dual-frequency in Ku and C-bands, Doris, a scatterometer and a microwave imager.