Atmosphere Driven Mass-Balance Sensitivity of Halji Glacier, Himalayas

Atmosphere

Dieter Scherer¹  Anselm Arndt²  Christoph Schneider² 

[1] Chair of Climatology, Technische Universität Berlin, 12165 Berlin, Germany;Geography Department, Humboldt-Universität zu Berlin, 10099 Berlin, Germany;

关键词: High Mountain Asia;    Himalayas;    Halji glacier;    COSIPY;    cryosphere;    climatic mass balance variability;   

DOI  :  10.3390/atmos12040426

来源: DOAJ

【 摘 要 】

The COupled Snowpack and Ice surface energy and mass balance model in PYthon (COSIPY) was employed to investigate the relationship between the variability and sensitivity of the mass balance record of the Halji glacier, in the Himalayas, north-western Nepal, over a 40 year period since October 1981 to atmospheric drivers. COSIPY was forced with the atmospheric reanalysis dataset ERA5-Land that has been statistically downscaled to the location of an automatic weather station at the Halji glacier. Glacier mass balance simulations with air temperature and precipitation perturbations were executed and teleconnections investigated. For the mass-balance years 1982 to 2019, a mean annual glacier-wide climatic mass balance of -0.48 meters water equivalent per year ($\mathrm{m}\mathrm{w}.\mathrm{e}./\mathrm{a}$) with large interannual variability (standard deviation $0.71$$\mathrm{m}\mathrm{w}.\mathrm{e}.$/$\mathrm{a}$) was simulated. This variability is dominated by temperature and precipitation patterns. The Halji glacier is mostly sensitive to summer temperature and monsoon-related precipitation perturbations, which is reflected in a strong correlation with albedo. According to the simulations, the climate sensitivity with respect to either positive or negative air temperature and precipitation changes is nonlinear: A mean temperature increase (decrease) of 1$\mathrm{K}$ would result in a change of the glacier-wide climatic mass balance of $-1.43$$\mathrm{m}\mathrm{w}.\mathrm{e}.$$/\mathrm{a}$ ( $0.99$$\mathrm{m}\mathrm{w}.\mathrm{e}.$$/\mathrm{a}$) while a precipitation increase (decrease) of 10 % would cause a change of $0.45$$\mathrm{m}\mathrm{w}.\mathrm{e}.$$/\mathrm{a}$ ( $-0.59$$\mathrm{m}\mathrm{w}.\mathrm{e}.$$/\mathrm{a}$). Out of 22 circulation and monsoon indexes, only the Webster and Yang Monsoon index and Polar/Eurasia index provide significant correlations with the glacier-wide climatic mass balance. Based on the strong dependency of the climatic mass balance from summer season conditions, we conclude that the snow–albedo feedback in summer is crucial for the Halji glacier. This finding is also reflected in the correlation of albedo with the Webster and Yang Monsoon index.

【 授权许可】

Unknown