Movement estimate of the Dongkemadi Glacier on the Qinghai-Tibetan Plateau using L-band and C-band spaceborne SAR data

We measured the complex motion of the Dongkemadi Glacier on Tanggula Mountain, Qinghai-Tibetan Plateau, using two-pass differential synthetic aperture radar interferometry (InSAR) with satellite L-band and C-band SAR data. We derived detailed motion patterns of the Dongkemadi Glacier for the winter seasons of 1996, 2007 and 2008 using a European Remote sensing Satellite-1/2 (ERS-1/2) tandem InSAR pair acquired from descending orbit and a 46-day-separation Advanced Land Observing Satellite (ALOS) InSAR pair acquired from ascending orbit. In this article, we focus on an analysis of the glacier's surface motion features and a validation of the results from the InSAR using Global Positioning System (GPS) survey data. The experimental results show that the glacier flow distribution displays strong spatial variations depending on elevation. The glacier is divided into four clearly defined fast-flowing units in terms of spatial variability of the glacier speed, with evidence from both ERS and ALOS/PALSAR InSAR pairs (PALSAR - Phased Array type L-band Synthetic Aperture Radar). Among the four fast-flowing units, three are on the Dadongkemadi Glacier (DDG) and one on the Xiaodongkemadi Glacier (XDG). The flow patterns are generally characterized by terrain complexity for both glacier branches. The upper central area of the DDG shows slow movement, maybe due to the convergent and uptaking effect of ice from steep slope areas with opposite flow directions.