Spatial and temporal variation characteristics of fractional vegetation cover in Qinghai province from 2009 to 2015

Qinghai province is in the west of China, northeast of Tibetan Plateau. Ecological environment is important here, and it is sensitive and vulnerable. In order to reveal and monitor the ecological environment changes in Qinghai province, in the study, fractional vegetation cover was estimated annually from 2009 to 2015 based on remote sensing images with 30m spatial resolution, then FVC spatial distribution characteristics and annual variation characteristics were analyzed, afterwards, FVC spatial variation characteristics were calculated by coefficient of variation (CV), finally, FVC change trends were calculated by the function of change rate (Slope). Results show that: In 2015, the average FVC in Qinghai province was 0.3243, in the grassland was 0.4506, in Sanjiangyuan was 0.4280 and in the three river basins was 0.4767. From 2009 to 2015, FVC fluctuated between 0.3004 and 0.3543 in Qinghai province, FVC in 2015 remained constant with it in 2009 in general, and FVC showed the similar distributions during the period that the higher FVC areas were distributed in the southeast, the lower FVC areas were distributed in the northwest relatively. The average CV in Qinghai province was 0.52, in the grassland zone was 0.29, in Sanjiangyuan was 0.35; Yellow River Basin had the highest variation stability of the three river basins. In the past 7 years (2009-2015), No change trend (68.29%) occupied most in 7 change trends in Qinghai province, 3 kinds of improving trends occupied larger than 3 kinds of deteriorating trends, and slightly change trends were dominant in all improving and deteriorating trends. Improving Obviously trend in Lancang River Basin occupied most in the three river basins.