Effect of debris on seasonal ice melt (2016?2018) on Ponkar Glacier, Manang, Nepal

• 作者: Rakesh Kayastha Reeju Shrestha Rijan B.Kayastha
• 来源期刊: 寒旱区科学（英文版）
• 年，卷（期）: 2020,（5）
• 所属期刊栏目: Articles
• 页码范围: 261-271
• 页数: 11页
• 语种: 英文

摘要

Supraglacial debris is widely present on glaciers in alpine environments and its distribution greatly affects glacier melt. The present study aims to determine the effect of debris on glacier ice melt on Ponkar Glacier, Manang District, Nepal. We estimated ice melt under various debris thickness using Energy Balance (EB) model and conductive heat flux methods, which are compared with in-situ observations. Four stakes are installed on the glacier at different debris thickness of 11?40 cm. Meteorological data from March 2016 to May 2018 are obtained from the Automatic Weather Station (AWS) installed on the glacier surface at an elevation of 3,881 m a.s.l. for the energy balance calculation. Debris surface tempera-ture and different debris depths are also measured on the glacier. The calculated ablation rates from the conductive heat flux method are 0.9, 1.62 and 0.41 cm/d on pre-monsoon, monsoon and post-monsoon, respectively, with mean debris thermal conductivity 1.04 W/(m?K). The net radiation shows little variation between the seasons, while turbulent heat flux varies in the season. Sensible heat flux was found to be highest in post-monsoon season due to a larger temperature gradi-ent between surface and air.