An unmanned cloud and fog observation vessel set sail recently from Lianyungang in Jiangsu province and started working in the Yellow Sea, marking the first long-duration voyage of the domestically developed vessel.

The China Meteorological Administration said on Tuesday that it covered a distance of about 204 kilometers and operated continuously for 16 hours.

The vessel will allow the administration to conduct large-scale meteorological and hydrological observations at sea, it said.

The country previously relied on fog observation stations near the coast that had detection ranges of only a few kilometers.

The unmanned vessel, developed by the administration's Meteorological Observation Center, is capable of autonomous and safe navigation and expands the observation range to about 330 km from the coast.