Dynamics and spatial pattern prediction of lakes in the northern Tanggula Mountains, Tibet, China

Abstract

This study assessed the dynamics of lakes in the north Tanggula Mountains in Tibet (NT area) and predicted the spatial changes. We used object-oriented classification and a spectral-angle vector change detection method to generate ecosystem distribution data for the NT area at five-year interval between 2000 and 2015. Based on this dataset, we measured the spatial pattern of lake dynamics and related geophysical and meteorological factors. A boost regression tree model was used to examine the contribution of these variables to lake area change, which were further used in a GEOMOD model to predict the distribution of lakes in 2030. The results showed that the area of lakes increased by 14.2% between 2000 and 2015, which was one of the main forms of ecosystem change in the NT area. In the study region, the area of 10 lakes out of the total 15 lakes with an area greater than 10 km2 increased and that of another five lakes decreased with a relatively low shrinkage ratio. Both the mean site area and site number of lakes increased, and the percentage of large lake sites increased slightly. Lakes located in areas with high altitude, high slope, low tempe-rature, low precipitation, or near glaciers had a higher probability of size increase. Locales near the current lake sites with low temperature, precipitation, and slope tended to become new parts of extant lakes. Following the trend of the last 15 years, lakes in the NT area would increase by 119 km2 by 2030, with the main form of lake expansion changing from inundation of area around large lakes to area around smaller sites.