BEIJING -- Field calibration test of two ocean observation satellites has been completed in North China's Inner Mongolia autonomous region, sources with the Ministry of Natural Resources said Monday.

The 35-day calibration test was led by the ministry's National Satellite Ocean Application Service and assisted by staff members from the China Academy of Space Technology.

The test included the calibrations of microwave scatterometers, which are key payloads carried by China's HY 2B satellite and China-France Oceanography Satellite. The two ocean-observation satellites were launched into space in October 2018.

The microwave scatterometer is a radar instrument that enables scientists to observe ocean surface winds and waves simultaneously. It is crucial in the study of the global marine environment and climate change.

According to the ministry, the test has achieved expected results.