Comprehensive evaluation and spatial-temporal changes of eco-environmental quality based on MODIS in Tibet during 2006-2016

In view of the lack of research on the screening and comprehensive evaluation of vegetation ecological parameters based on remotely sensed date products, this paper firstly proposes a method to evaluate the vegetation eco-environmental quality in Tibet by PCA (principal component analysis). Based on five indicators, including fractional vegetation coverage (FVC), leaf area index (LAI), gross primary productivity (GPP), land surface temperature (LST) and modified wet (Wet) from MODIS satellite data, the law and mechanism of spatial-temporal changes of eco-environmental quality in Tibet in the last 10 years are explored. The experimental results show that: (1) The comprehensive quality of the eco-environmental quality in Tibet is relatively fragile, and the spatial difference in eco-environmental quality is significant. It is excellent in the southeast but poor in the northwest. (2) During the period from 2006 to 2016, the eco-environmental quality in Tibet shows a trend of improving overall. In terms of time series, the proportion of areas improved and degraded in the past 10 years was 31.88% and 4.13% respectively. In terms of spatial distribution, the improved areas are distributed in the northwestwen, central and eastern parts, but but the degraded areas are distributed in the southeastern parts. (3) Improvements in hydrothermal conditions (especially the increase in precipitation) and human protection policies have led to improvements in the eco-environmental quality in the western and central Tibet. The strengthening of social and economic activities is the main reason for the deterioration of the eco-environmental quality in the southeast of Tibet. © 2019, Science Press. All right reserved.