XINING - The surface area of China's largest inland saltwater lake has been expanding for eight years, according to the latest remote sensing survey.

The Qinghai Lake in Northwest China's Qinghai province measured 4,354.28 square km, according to satellite data collected on July 19 and published on Sunday, said Zhou Bingrong, deputy chief of the provincial institute of meteorological sciences.

The figure was 14.58 square km larger than the same time last year, and the largest in 12 years, he said.

Zhou's institute has been carrying out dynamic surveillance of the lake's surface area since 2001, when the lake was shrinking due to climate change and human activity.

Results of their surveillance are published twice a year, during and after the flood season in July and September, respectively.

"We have noticed an apparent increase of water since 2005, thanks to more rainfall and sustained environmental protection efforts," said Zhou.

Such efforts have ranged from returning croplands to grasslands to preserve highland vegetation and forests, as well as weather modification schemes to increase rainfall, he said.

This summer in particular, the lake area received above-average precipitation. Tianjun county alone - where the lake is located - reported at least twice as much rainfall as last year.

The Qinghai Lake, nestled at the northeastern part of the Qinghai-Tibet Plateau, is China's largest inland lake as well as the country's largest saltwater lake. It had been shrinking since the 1950s, but is slowly being restored thanks to conservation efforts in the past decade.

An official survey showed that in 2008, the acreage of Qinghai Lake was 4,317 square km, up 132 square km from 2004.