Extracting the spatio-temporal evolution and geographical features of shrinking Gongga Mountain glacier group during 1989–2017

Abstract

The climate-induced spatio-temporal evolutionary characteristics of glaciers have a strong response in understanding the surface earth system processes, including hydrology, ecology, and topography. With use of multispectral remote sensing, this study explores the long-time glacier shrinkage evolution and their geographical features of Gongga Mountain glaciers (i.e. Gongga Mountain glacier group), in eastern Qinghai-Tibetan Plateau, China. We used a band ratio and decision-tree classification mixed method to automatically delineate Gongga Mountain glaciers shrinking nature. Based on the multispectral Landsat images over nearly 30 years, the long-time spatio-temporal shrinkage evolution of Gongga Mountain glaciers was extracted, in which the glacier shrinkage area changes are consistent with the results from previous works. This study analyzed the nature of shrinking glaciers with topographic derivatives (i.e., different glacier scale, altitude, slope gradient, and slope direction). We noticed that the characteristic of shirking glaciers is associated with the topographic variables. The maximum shrinkage was concentrated at altitudes of 5000–5500 m, and a slope angle of 30° in the south direction. Findings shed light that glaciers in our study area are correlated with temperature changes and precipitation with a correlation coefficient of −0.97 and 0.35, respectively, suggesting that the decreasing glaciers are highly correlated with the temperature increase. This study implies the usefulness of remote sensing in understanding the long-time ecological environment change and helping manage the potential glacial disasters in eastern Qinghai-Tibet Plateau.