Method for Detecting Snow Lines From MODIS Data and Assessment of Changes in the Nianqingtanglha Mountains of the Tibet Plateau

Abstract

Change in the snow line elevation (SLE) in the mountains, which is generally sensitive to climate change, is one of the indicators used to monitor climatic behavior. We propose a method to extract the snow line of the minimum snow cover extent using the multi-temporal MODerate-resolution Imaging Spectroradiometer (MODIS) reflectance data combining with higher-spatial-resolution Digital Elevation Model (DEM) data in high mountain area. The changes in the SLE of minimum snow cover and their response to climate warming were assessed from 2000 to 2009 in the Nianqingtanglha mountains in the Tibet Plateau. The results show that the annual mean SLE rose from 5733 m in 2004 to 5828 m in 2009. The variability of SLE, moreover, demonstrated a significant correlation with temperature <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$({\rm R}^{2}=0.82)$</tex> </formula> and precipitation <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$({\rm R}^{2}=0.65)$</tex></formula> . Our study indicates that the SLE of the minimum snow cover every year can be better detected taking the advantage of MODIS multi-temporal data and combining with higher spatial resolution DEM data which guarantees enough snow line pixels to perform sound statistical analyses.