Fluctuations of unstable mountain glaciers: scale and character

Abstract

The paper describes the characteristics and behavior of unstable glaciers in the Pamirs, central Asia, over the last 30 years. These glaciers are divided into three groups: glaciers with registered surges; glaciers with signs of current instability; glaciers with signs of instability in the recent past. Examples are given to illustrate the nature of glacier fluctuations at a time of general glacier retreat in the Pamirs. A description is given of the evolution of Medvezhiy surging glacier, which was the subject of detailed annual observation from 1963 to 1991. Comparative characteristics of two building-up stages of this glacier, 1964–72 and 1974–88, are produced. On the basis of aerotopographic monitoring and with the aid of computer analysis, the kinematics of the glacier surface during the 1988–89 surge are traced in detail and the role of microsurges in the course of glacier build-up and the glacier surge is established.

Fifty years of studying the Medvezhiy Glacier (West Pamirs) by the Institute of Geography, RAS

“…рис . 4 в работе [33]) . В результате ана лиза этих материалов были прослежены: форми рование наступающего конца ледника и посте пенное возрастание скорости его продвижения от 0,2 до 2 м/сут на начальном этапе подвижки (лето 1988 г .…”

“…В ходе мониторинга в сотрудничестве с лабо раторией космических методов МГУ был прове дён специальный эксперимент по определению методом аэропсевдопараллаксов скорости дви жения льда на всём протяжении языка, включая его подледопадную и ледопадную зоны [33] . По лученная в 1988-1991 гг .…”

Surging Glaciers in High Mountain Asia between 1986 and 2021

“…The most significant advance occurred between 1996 and 1998, when glacier length and area increased by 1979 m (989 m/a) and 0.8 ± 0.2 km 2 , respectively, reaching the surging peak. The terminus of this tributary merged into and overlaid the trunk glacier, with a lobed terminus and a distinctive pushback curl [77]. Tributary glacier A2 started surging the earliest (1991), had the longest surge phase (21 years), and advanced slowly from 1991 to 2004.…”

Surging glaciers in High Mountain Asia between 1986 and 2021

“…The most significant advance occurred between 1996-1998, when glacier length and area increased by 1978.95 m (989.48 m/a) and 0.81 km 2 , respectively, reaching the surging peak. The end of this branch merges into and overlies the main glacier, with a lobed end and a distinctive pushback curl (Kotlyakov et al, 1997). Branch glacier A2 started surging the earliest ( 1991…”