Journal Article Comparison of multiple glacier inventories with a new inventory derived from high-resolution ALOS imagery in the Bhutan Himalaya

Nagai, Hiroto  ,  Fujita, Koji  ,  Sakai, Akiko  ,  Nuimura, Takayuki  ,  Tadono, Takeo  ,  永井, 裕人  ,  藤田, 耕史  ,  坂井, 亜規子  ,  縫村, 崇行  ,  田殿, 武雄

10 ( 1 )  , pp.65 - 85 , 2016-01-18 , European Geosciences Union
Digital glacier inventories are invaluable data sets for revealing the characteristics of glacier distribution and for upscaling measurements from selected locations to entire mountain ranges. Here, we present a new inventory of Advanced Land Observing Satellite (ALOS) imagery and compare it with existing inventories for the Bhutan Himalaya. The new inventory contains 1583 glaciers (1487 plus or minus 235 sq km, km2), thereof 219 debris-covered glaciers (951 plus or minus 193 sq km, km2) and 1364 debris-free glaciers (536 plus or minus 42 sq km, km2). Moreover, we propose an index for quantifying consistency between two glacier outlines. Comparison of the overlap ratio demonstrates that the ALOS-derived glacier inventory contains delineation uncertainties of 10-20 % which depend on glacier size, that the shapes and geographical locations of glacier outlines derived from the fourth version of the Randolph Glacier Inventory have been improved in the fifth version, and that the latter is consistent with other inventories. In terms of whole glacier distribution, each data set is dominated by glaciers of 1.0-5.0 km(exp 2) area (31-34 % of the total area), situated at approximately 5400 m elevation (nearly 10 % in 100 m bin) with either north or south aspects (22 and 15 %). However, individual glacier outlines and their area exhibit clear differences among inventories. Furthermore, consistent separation of glaciers with inconspicuous termini remains difficult, which, in some cases, results in different values for glacier number. High-resolution imagery from Google Earth can be used to improve the interpretation of glacier outlines, particularly for debris-covered areas and steep adjacent slopes.
Physical characteristics: Original contains color illustrations
形態: カラー図版あり

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