Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Debris-covered glaciers are widely distributed in Western China. Their ablation areas are covered byvarying degrees of rock debris, and consequently, their melting statuses differ greatly when compared to debrisfreeglaciers. There is currently a need for melting simulations to better understand debris- covered glaciers. Inthis paper, driven by field meteorological data, an energy balance model for debris- covered glaciers has beenused to simulate the energy and ablation in debris-covered areas of Qingbingtan Glacier No. 72 in Mt. Tomor,Tianshan. Based on the heat conduction process and the energy balance equation, the model calculates the debrissurface temperature and the internal temperature of the debris, then estimates the subdebris melt using the internaldebris temperature. The results showed that the modeled ablation was 0.39 m w.e. in the summer of 2008, and thesimulation accuracy (R2 = 0.92, RMSE = ± 0.03 m w.e.) was higher when compared with the field data. Thesimulated debris temperatures at the surface and a depth of 10 cm inside the debris were also found to fit wellwith the measured data (R2 = 0.91 and 0.60, respectively). During energy exchange in the debris area, netshortwave radiation was the only energy income item, and sensible heat flux was the largest energy expenditureitem (49.7%), followed by the heat conduction flux (ablation heat consumption) (25.8%), net longwave radiation(19.8%), and latent heat flux (4.6%), while precipitation heat was <1%. Cloud cover had a significant impact onthe meteorological and energy characteristics of the debris area. Under overcast conditions, the incomingshortwave radiation in the debris area decreased from 854 W·m- 2 on sunny days to 587 W·m− 2, while thedownward longwave radiation and relative humidity increased, and the average ablation decreased by 12%, whencompared with sunny days. In addition, the sensitivity analysis of the key parameters for debris shows that thesimulated ablation is most sensitive to the changes in thermal conductivity, and the changes in albedo and surfaceroughness cannot be ignored.
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