Glacier changes from a new inventory, Nianchu river basin, Tibetan Plateau

The ice cover of the Nianchu river basin, southern Tibetan Plateau, was mapped for 2005, using a SPOT5 scene, and for 1990 and 2000 from Landsat TM/ETM. Digital elevation models (DEMs) were generated from 1:50 000 scale topographical maps. The results show that in 2005 there were 136 glaciers in this basin, with a total area of 224 km(2). Of these, 37 glaciers had an area >1 km(2) and 10 were larger than 5 km(2); the average snout altitude was 5608 m a.s.l. A comparison of outlines from the last 15 years shows that most glaciers have decreased in size; none have advanced. From 1990 to 2005, Xiaquepu glacier No. 56 and Shimozongpu glacier No. 38 retreated 310 and 560 m, respectively. The mean reduction in glacier surface area was 5% (10 a)(-1) while the area of glacial lakes expanded by 10%; nine new lakes formed in this basin over the 15 year period. Because air temperatures here have been increasing, while precipitation has remained steady, glacier retreat is considered to be related to rising temperature.