Multi-temporal elevation changes of Fedchenko Glacier (Tajikistan) from 1928 to 2021

The Fedchenko Glacier in Tajikistan's central Pamir region is one of Asia's longest glacier and has been a focal point for scientific investigation spanning the 20th and 21st centuries, yielding a valuable historical dataset for Central Asia. This study explores elevation changes from 1928 to 2021 from topographic maps from 1928 and 1958, KH-9 spy satellite data from 1980, SPOT5 satellite data from 2011, and Pléiades satellite data from 2017, 2019, and 2021, along with GNSS surveys for absolute co-registration. The 93-year mean rate of elevation change is -0.46 m yr- 1. Notably, the tongue's thinning rate is twice as negative as the longterm average in two sub-periods (1958-1980 and 2010-2021), possibly linked to a surge-like event for the earlier period. Analyses of ERA5 reanalysis (1950-2021) and Fedchenko meteorological station data (1936-1991) reveal a dry anomaly in 1958-1980 followed by a wet anomaly in 1980-2010, potentially offsetting temperature-induced mass losses. The contemporary thinning rates align with a broader trend of generalised mass losses in the Pamir region.