Fengyun 3E, the world's first early morning orbit weather satellite that China launched for civil use on Monday, will improve global weather forecast by filling in the data gap in a certain time of a day and assist in achieving 100 percent global data coverage every six hours, experts said.

Zhang Peng, deputy director of the National Satellite Meteorological Center, also the chief commander of the Fengyun 3 series ground system, said Fengyun 3E with a designed lifetime of eight years belongs to the polar-orbiting satellite group whose combination monitors weather, climate and environment of the whole world.

Polar orbits that pass over the north and south poles in a north-south ellipse are synchronous with the Sun. Satellites on the orbits pass places on the Earth at the same local time.

"Polar-orbiting satellites can be divided by orbits whose passes are at different local times. Before Fengyun 3E, polar-orbiting weather satellites operated only in AM and PM orbits above the Earth. The newly launched one will complement the two previous orbits in time period and spatial coverage to increase mid- and long-term weather forecast's accuracy," he said.

In an early morning orbit, a satellite usually passes downward over the equator between 5 and 6 am while on its symmetrical side of the planet it passes upward over the equator between 5 and 6 pm, the center said.

The AM orbital pass over the equator downward occurs at around 10 with the PM at about 1:40, the center said.