Southwest-facing slopes control the formation of debris-covered glaciers in the Bhutan Himalaya

Hiroto Nagai, K. Fujita, T. Nuimura, A. Sakai

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

To understand the formation conditions of debris-covered glaciers, we examined the dimension and shape of debris-covered areas and potential debris-supply (PDS) slopes of 213 glaciers in the Bhutan Himalaya. This was undertaken using satellite images with 2.5 m spatial resolution for manual delineation of debris-covered areas and PDS slopes. The most significant correlation exists between surface area of southwest-facing PDS slopes and debris-covered area. This result suggests that the southwest-facing PDS slopes supply the largest quantity of debris mantle. The shape of debris-covered areas is also an important variable, quantitatively defined using a geometric index. Elongate or stripe-like debris-covered areas on north-flowing glaciers are common throughout the Bhutan Himalaya. In contrast, south-flowing glaciers have large ablation zones, entirely covered by debris. Our findings suggest that this difference is caused by effective diurnal freeze-thaw cycles rather than seasonal freeze-thaw cycles, permafrost degradation, or snow avalanches. In terms of geographic setting, local topography also contributes to glacier debris supply and the proportion of debris cover on the studied glaciers is suppressed by the arid Tibetan climate, whereas the north-to-south asymmetric topography of the Bhutan Himalaya has less influence on the proportion of debris cover.

Original languageEnglish
Pages (from-to)1303-1314
Number of pages12
JournalCryosphere
Volume7
Issue number4
DOIs
Publication statusPublished - 2013 Sep 9
Externally publishedYes

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glacier
freeze-thaw cycle
topography
snow avalanche
ablation
permafrost
spatial resolution
surface area
mantle
climate

ASJC Scopus subject areas

  • Water Science and Technology
  • Earth-Surface Processes

Cite this

Southwest-facing slopes control the formation of debris-covered glaciers in the Bhutan Himalaya. / Nagai, Hiroto; Fujita, K.; Nuimura, T.; Sakai, A.

In: Cryosphere, Vol. 7, No. 4, 09.09.2013, p. 1303-1314.

Research output: Contribution to journalArticle

Nagai, Hiroto ; Fujita, K. ; Nuimura, T. ; Sakai, A. / Southwest-facing slopes control the formation of debris-covered glaciers in the Bhutan Himalaya. In: Cryosphere. 2013 ; Vol. 7, No. 4. pp. 1303-1314.
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