2000-2019年青海地区植被总初级生产力遥感估算及时空变化分析

青海作为三江源所在地,监测其生态系统变化对我国的生态文明建设具有战略意义.植被总初级生产力(GPP)是陆地生态系统碳循环的重要组分.采用MODIS卫星遥感数据和土壤背景校正NIRv模型,结合3个地面站点的通量观测数据,估算了2000-2019年青海地区的GPP,并结合土地利用数据和气象数据分析了其时空分异特征及对气候变...

Remote-sensing estimation of vegetation gross primary productivity and its spatiotemporal changes in Qinghai Province from 2000 to 2019

The Qinghai region is the source of the Yangtze， Yellow， and Lancang rivers， and covers an area of 722300 km². Monitoring information on the spatiotemporal variability of local ecosystems is strategically significant for the evolution of sophisticated future ecological management in China. Vegetation gross primary production （GPP） is the key component of the terrestrial ecosystem carbon cycle. A recent study has found that a vegetation index， the near-infrared radiance of vegetation （NIRv）， is a good proxy of GPP. Using MODIS satellite remote sensing data， a soil-adjusted NIRv model， and ground flux observation data for three sites， we estimated the GPP across Qinghai from 2000 to 2019. We also analyzed its spatial and temporal variations and responses to climate change leveraging land cover data and meteorological data. The results indicate that： 1） GPP estimations by the soil-adjusted NIRv model agree well with ground observations （R²=0.91， P<0.001）， and is more suitable than MODIS GPP products for this area. 2） The multi-year averaged GPP across the Qinghai region is 140.5 Tg C·yr^-1， with a significant increasing trend of 1.25 Tg C·yr^-1 （P<0.05）， from 2000 to 2019. 3） The spatial distribution of GPP in Qinghai is characterized by an increase from west to east. Significant difference exists in the interannual variations in GPP， depending on land cover types. 4） Overall， GPP has a higher correlation with temperature than with precipitation， but such correlation also shows substantial spatial variation.