Long-Term Deceleration of Glaciers in the Eastern Nyainqentanglha Mountains, Southeastern Tibetan Plateau, Revealed from Landsat Images

Temperate glaciers are very sensitive to variations in temperature and precipitation, and thus represent a good indicator of climate change. By exploiting complete Landsat archives during periods of 1988-1990, 2000-2002 and 2014-2016, we derived three velocity maps of the temperate glaciers on the eastern Nyainqentanglha Mountains in southeastern Tibetan to reveal the long-term changes of glacier surface velocity. Our results show that all the investigated glaciers experienced deceleration, with rates of deceleration varying from 4.15% to 29.8% per decade during the period from 1988-1990 to 2014-2016, showing heterogeneous deceleration patterns. A significant rise in temperature and an insignificant decrease in precipitation was found from the meteorological data of the nearby meteorological station. The region-wide deceleration of glaciers was, thus, attributed to the negative mass balance induced mainly by the rise in temperature. The averaged rates of deceleration for periods from 1988-1990 to 2000-2002 and from 2000-2002 to 2014-2016 are 20.97% and 22.02% per decade, respectively, indicating a nearly even speed of deceleration in velocities during study periods. The nearly even speed of deceleration in velocities and the accelerating mass loss trend from periods before the 2000s to after the 2000s highlighted the complexity of the relationship between mass balance and glacier velocity.