Recent changes in freezing level heights in High Asia and their impact on glacier changes

Abstract

The heights of the atmospheric freezing level have increased over most glacierized areas of High Asia during 1971-2010, especially in the Altai Mountains, the eastern Tianshan Mountains, and the northeastern margins of the Tibetan Plateau. The systematic increase of freezing level heights (FLHs) is evidenced from both radiosonde and National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data. Eleven glaciers with long-term observations are selected in typical high-elevation mountain ranges to examine the relationship between changes in FLHs and cryospheric response. Long-term trends in glacier mass balance and equilibrium line altitude (ELA) show significant correlations with changes in FLHs. A rise of 10 m in summer FLH causes mass balance of reference glaciers in High Asia to decrease by between 7 and 38 mm (water equivalent) and ELA to increase by between 3.1 and 9.8 m, respectively, depending on location. Both relationships are statistically significant (p < 0.01) for most reference glaciers. Thus, rapid deglaciation in these high mountain ranges during recent decades is related to the increase in FLH. Similar relationships may exist in other high-elevation glaciers of High Asia with changes in FLHs having significant ecological and social consequences, especially in arid and semiarid regions.

Mass balance observations and reconstruction for Batysh Sook Glacier, Tien Shan, from 2004 to 2016

“…Therefore, the different reactions of glaciers in close vicinity are often related to other influencing factors such as: a) their different hypsometry (Kuhn et al, 1985), b) the influence of changing shortwave net radiation, which is controlled by the diverse characteristics of the albedo related to dirt or debris materials on the glacier surface, and varying fresh snowfalls during the summer months (Fujita and Ageta, 2000;Fujita, 2008aFujita, , 2008bLi et al, 2011;Naegeli et al, 2015), or c) a strong increase in the freezing level as discussed for Urumqihe Glacier No. 1 by Wang et al (2014).…”

Recent changes of two selected glaciers in Hami Prefecture of eastern Xinjiang and their impact on water resources

“…Due to climate warming, observations have identified a general thinning and retreat of glaciers globally (e.g. Li et al, 2006;Vanlooy and Forster, 2008;Kutuzov and Shahgedanova, 2009;Wang et al, 2011b;Wang et al, 2014aWang et al, , 2014bWang et al, , 2014c. The glacier runoff derived from changes of glaciers is an important source of fresh water to support the sustained development of the ecological environment, industry, and agriculture of downstream counties in arid regions (Fountain and Tangborn, 1985;Braithwaite and Olesen, 1988;Aizen et al, 1995Aizen et al, , 1996Kaser et al, 2010;Immerzeel et al, 2010Immerzeel et al, , 2012Jacob et al, 2012;Sorg et al, 2012).…”

Reconstruction of surface air temperature in a glaciated region in the western Qilian Mountains, Tibetan Plateau, 1957–2013 and its variation characteristics

“…In cryospheric research, air temperature is a vital parameter in mass-balance and energybalance models (Sicart et al, 2011;Jarosch et al, 2012;Gurgiser et al, 2013). However, in-situ observations for most glaciated areas are generally scarce (Zhang et al, 2012a;Wang et al, 2014a). The reconstruction of meteorological parameters, especially the surface air temperature, is needed in mountain research and cryospheric science.…”