Up-glacier propagation of surface lowering of Yala Glacier, Langtang Valley, Nepal Himalaya

Abstract We quantify the surface elevation changes along Yala Glacier in Langtang Valley, Nepal Himalaya, since 1981 using geodetic methods to understand recent evolution and current state of small debris-free glaciers across region. analyse differential global positioning system measurements aerial stereo imagery that were acquired 2007, 2009, 2012 2015 generate digital models for each calculation period. Continuous lowering has mainly been observed down-glacier area during periods, although a large degree variability exists, with this trend propagating up-glacier years. The area-weighted glacier mass balances range from −0.98 ± 0.27 −0.26 0.30 m w.e. −1 five periods (1981–2007, 2007–2009, 2009–2012, 2012–2015 2007–2015). These calculated mass-balance data reveal undergone accelerated loss late 2000s, which is consistent results previous situ measurement remote-sensing studies.