Glacier Mass Loss during the 1960s and 1970s in the Ak-Shirak Range (Kyrgyzstan) from Multiple Stereoscopic Corona and Hexagon Imagery

Abstract

Abstract:Comprehensive research on glacier changes in the Tian Shan is available for the current decade; however, there is limited information about glacier investigations of previous decades and especially before the mid 1970s. The earliest stereo images from the Corona missions were acquired in the 1960s but existing studies dealing with these images focus on single glaciers or small areas only. We developed a workflow to generate digital terrain models (DTMs) and orthophotos from 1964 Corona KH-4 for an entire mountain range (Ak-Shirak) located in the Central Tian Shan. From these DTMs and orthoimages, we calculated geodetic mass balances and length changes in comparison to 1973 and 1980 Hexagon KH-9 data. We found mass budgets between −0.4 ± 0.1 m·w.e.a −1 (1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976)(1977)(1978)(1979)(1980) and −0.9 ± 0.4 m·w.e.a −1 (1973)(1974)(1975)(1976)(1977)(1978)(1979)(1980) for the whole region and individual glaciers. The length changes, on the other hand, vary heterogeneously between +624 ± 18 m (+39.0 ± 1.1 m·a −1 ) and −923 ± 18 m (−57.7 ± 1.1 m·a −1 ) for [1964][1965][1966][1967][1968][1969][1970][1971][1972][1973][1974][1975][1976][1977][1978][1979][1980]. An automation of the processing line can successively lead to region-wide Corona data processing allowing the analysis and interpretation of glacier changes on a larger scale and supporting a refinement of glacier modelling.

Occurrence, evolution and ice content of ice‐debris complexes in the Ak‐Shiirak, Central Tien Shan revealed by geophysical and remotely‐sensed investigations

“…The large surface lowering visible in the upper part of the accumulation regions which continue to the non‐glacierised areas (Figure (A), (B), d) stem from errors in the DEMs. These areas are at the edges of individual Corona DEMs that were mosaicked to a single DEM (Goerlich et al, ), and as such some erroneous elevation values are to be found.…”

“…Three stereo pairs of Corona KH‐4A data acquired in November 1964 were used to generate a DEM with a resolution of 10 m and subsequent orthoimages using the Remote Sensing Software Graz (RSG) (cf. Goerlich et al, ). The quality of the DEMs was promising, but problems occurred especially in areas with low contrast such as steep slopes in shadow and bright snow covered areas, especially with the KH‐4A DEM.…”

“…Mapped ice-debris complexes were compared with existing glacier inventories for the years 1964, 1980 and 2007 which are based on Corona KH-4, Hexagon KH-9 and Landsat data (Osmonov et al, 2013;Pieczonka and Bolch, 2015;Goerlich et al, 2017).…”

Multi-decadal mass balance series of three Kyrgyz glaciers inferred from modelling constrained with repeated snow line observations

“…The SMB was measured intensively from 1967 to 1998 (Suslov et al, 1980;Glazirin et al, 1993) and the monitoring was re-established in 2011 . Since then, annual glaciological surveys were continuously carried out in late August.…”

“…Furthermore, other authors focused on selected regions of the central and northern Tien Shan (e.g. Aizen et al, 2007;Pieczonka et al, 2013;Pieczonka and Bolch, 2015;Goerlich et al, 2017), deriving glacier-specific geodetic mass balances. These studies often cover large areas, but temporal resolution is typically limited to 5 years or longer periods.…”