Variabilities in Climate Sensitivities and Mass Balance of Four High Mountain Asian Glaciers

We report on the mass balance evolution and climate sensitivities of four glaciers from moderately dry to moderately wet climate zones of High Mountain Asia over the last five decades. We focus on Chhota Shigri Glacier located in the western Himalaya (RGI region: South Asia west), Tuyuksu and Sary Tor glaciers (Northern and Central Tien Shan, Central Asia), and an unnamed glacier (hereafter Glacier No. 4) (Eastern Himalaya, South Asia east). Continentality index indicates Chhota Shigri and Sary Tor as most continental (43 and 41) glaciers, Tuyuksu as intermediate (34) and Glacier No. 4 as the most maritime glacier (22). Using declassified spy satellite imagery from the 1970s and 1980s and recent high-resolution optical satellite images, we estimated glacier mass loss rates ranging from -0.3 ± 0.1 m w.e a-1 for Chhota Shigri and Tuyuksu glaciers (1971-2020), -0.4 ± 0.1 m w.e. a⁻¹ for Glacier No. 4 (1969–2022), and -0.6 ± 0.1 m w.e a-1 for Sary Tor Glacier (1973- 2023). We calibrated a mass balance model (SnowModel) coupled with an ice dynamics model to simulate the long-term annual and seasonal mass balance of each glacier. Subsequently, we used the calibrated model to calculate the dynamic mass balance sensitivity of each glacier to the changes in temperature and precipitation. Our results reveal that Sary Tor Glacier is least sensitive to climate changes. However, as this glacier has observed significantly increasing temperature over the last decades, it may witness an increasing mass loss due to its strong sensitivity to temperature changes. Chhota Shigri Glacier’s mass balance is less sensitive to changes in temperature and precipitation compared to Tuyuksu Glacier. In addition, no significant trends in either temperature or precipitation was observed, implying a more stable response of the glacier to climate in near future. Tuyuksu Glacier accumulates mass both in summer and winter, and it is strongly influenced by temperature changes. With no significant increase in precipitation to offset the mass loss due to increased temperature, this glacier will likely experience an increased mass loss in coming decades. Glacier No. 4 has the highest sensitivity to climate. With a warming trend observed in this region, this glacier is expected to witness highest mass loss among the four in the coming years.