Abstract This study examines changes in the glacier area, volume, and distribution in the Upper Karnali Basin of Nepal from 2000 to 2023 using optical, thermal, and radar remote sensing data, including snow area, multi-temporal digital elevation models (DEMs), land surface temperature, and in situ meteorological data. The study reveals a 15.2% reduction in glacier area, corresponding to an annual average loss of 585 ha. The findings highlight significant spatial variability, with some sub-basins experiencing slight increases while others exhibit significant reductions. Key observations include the fragmentation of larger glaciers into smaller masses, an upward migration to cooler altitudes above 5100 m, and an increase in the equilibrium line altitude (ELA). Glaciers in the Upper Karnali Basin have experienced a volume loss of 427.73 million m3. Between 2010 and 2023, glaciers in the Upper Karnali Basin experienced significant volume loss, particularly at altitudes between 5174 and 5773 m and on slopes ranging from 12 to 26°, accounting for 87 and 77% of the decline, respectively. Temperature trends indicate a consistent increase in minimum and maximum values, coupled with precipitation variability, further exacerbating glacier retreat. Research highlights <UnorderedList Mark="Bullet"> <ItemContent> A 15.2% decrease in glacier area occurred from 2000 to 2023, resulting in an annual loss of 585 ha. Sub-basin-specific changes indicate some slight increases; however, there are overall significant reductions. </ItemContent> <ItemContent> The annual glacier volume loss is estimated at 427.73 million m3, primarily occurring at altitudes between 5174 and 5773 m (a.s.l.) and on slopes ranging from 12 to 26°, as well as on southward-oriented glaciers. </ItemContent> <ItemContent> Larger glaciers have fragmented into smaller masses, migrating upward to cooler altitudes above 5100 m (a.s.l.). Equilibrium line altitude has increased, indicating significant glacial aerial shrinkage. </ItemContent> <ItemContent> Rising temperatures, along with variability in precipitation, contribute to accelerated melting. </ItemContent> </UnorderedList>

Status and changes in glaciers in the Upper Karnali Basin, West Nepal: Assessing topographic influences on area, fragmentation, and volume

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发表日期：

2025年10月25日

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Motilal Ghimire,
Til Prasad Pangali Sharma,
Raju Chauhan,
Sher Bahadur Gurung,
Sundar Devkota,
Krishna Prasad Sharma,
Dibas Shrestha,
Zhao Wei,
Niroj Timalsina

摘要

Abstract

This study examines changes in the glacier area, volume, and distribution in the Upper Karnali Basin of Nepal from 2000 to 2023 using optical, thermal, and radar remote sensing data, including snow area, multi-temporal digital elevation models (DEMs), land surface temperature, and in situ meteorological data. The study reveals a 15.2% reduction in glacier area, corresponding to an annual average loss of 585 ha. The findings highlight significant spatial variability, with some sub-basins experiencing slight increases while others exhibit significant reductions. Key observations include the fragmentation of larger glaciers into smaller masses, an upward migration to cooler altitudes above 5100 m, and an increase in the equilibrium line altitude (ELA). Glaciers in the Upper Karnali Basin have experienced a volume loss of 427.73 million m³. Between 2010 and 2023, glaciers in the Upper Karnali Basin experienced significant volume loss, particularly at altitudes between 5174 and 5773 m and on slopes ranging from 12 to 26°, accounting for 87 and 77% of the decline, respectively. Temperature trends indicate a consistent increase in minimum and maximum values, coupled with precipitation variability, further exacerbating glacier retreat.

Research highlights

A 15.2% decrease in glacier area occurred from 2000 to 2023, resulting in an annual loss of 585 ha. Sub-basin-specific changes indicate some slight increases; however, there are overall significant reductions.

The annual glacier volume loss is estimated at 427.73 million m³, primarily occurring at altitudes between 5174 and 5773 m (a.s.l.) and on slopes ranging from 12 to 26°, as well as on southward-oriented glaciers.

Larger glaciers have fragmented into smaller masses, migrating upward to cooler altitudes above 5100 m (a.s.l.). Equilibrium line altitude has increased, indicating significant glacial aerial shrinkage.

Rising temperatures, along with variability in precipitation, contribute to accelerated melting.