Details

Autor(en) / Beteiligte

• Häusler, Hermann
• Ng, Felix
• Kopecny, Alexander
• Leber, Diethard

Titel

Remote-sensing-based analysis of the 1996 surge of Northern Inylchek Glacier, central Tien Shan, Kyrgyzstan

Ist Teil von

• Geomorphology (Amsterdam, Netherlands), 2016-11, Vol.273, p.292-307

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2016

Link zum Volltext

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• The evolution of Northern Inylchek Glacier and its proglacial lake - Upper Lake Merzbacher - during its 1996 surge and the surrounding decades is analyzed with remote sensing imagery. Overall retreat of the glacier from 1943 to 1996 enlarged the lake to 4km long and ≈100m deep. The surge in 1996 initiated between 12 September and 7 October and advanced the glacier by 3.7km to override most of Upper Lake Merzbacher. The surge phase probably ended in December 1996 and involved mean flow velocities across the lower trunk of the glacier that reached 50md−1 over a 32-day period. Water displaced by the surge from Upper Lake Merzbacher, totalling 1.5×108m3 in volume, accelerated filling of Lower Lake Merzbacher downvalley and helped trigger this marginal ice-dammed lake to outburst in a jökulhlaup around late November/early December. The characteristics and duration of the surge render it as similar to temperate glacier surges elsewhere. It may have been facilitated by low basal friction caused by water-saturated sediments in the upper lake bed. Furthermore, bathymetric measurements show that the surge evacuated much sediment into the upper lake, causing its depth to reduce from 20 to 30m in 1996 to 8m by 2005 and 2m by 2011; the corresponding deposition rates imply glacier-catchment specific mean sediment yields of 1.4 to 3.4×103Mgkm−2a−1 in the years after the surge. Our study documents novel interactions within a cascade system of glaciers and lakes that exhibits surging and outburst-flood behavior. [Display omitted] •First detailed description of glacier surge in central Tien Shan, eastern Kyrgyzstan•Time series analysis of remote sensing images 1943–2011•Analysis of “chain reaction” linking water displacement by a surging glacier to triggering of a glacier lake outburst flood•Field investigations of the morphology of a surge-type glacier and bathymetry of its proglacial lake