China will launch four ocean-observation satellites within the coming 16 months, according to China Youth Daily.

Two will be launched in September and November this year, and the other two will be sent into space in 2021, the newspaper quoted director of the National Ocean Satellite Application Center Jiang Xingwei as saying.

As of August, China has independently developed and launched seven Haiyang satellites, named after the Chinese word for "ocean" and given the "HY" designation for short.

The country launched its first ocean-monitoring satellite, the HY 1A, on May 15, 2002, and sent HY 1D into orbit in June this year.

The space-based remote-sensing technology has been used in fields such as marine environmental resources survey, marine disaster prevention and alleviation, marine economy, marine ecology and maritime security, according to a sub-forum of the World Marine Science and Technology Conference.

The HY 2A and HY 2B satellites can monitor typhoons in the northwest Pacific region and capture information on all the typhoons throughout the year, providing support for typhoon forecasting during the flood season.