Multi-decadal mass balance series of three Kyrgyz glaciers inferred from transient snowline observations

Abstract

Abstract.Glacier mass balance observations in the Tien Shan and Pamir mountains are sparse and often discontinuous. Nevertheless, glaciers are one of the most important components of the high-mountain cryosphere in the region; they strongly influence water availability in the arid, continental and intensely populated downstream areas. This study provides reliable and continuous mass balance series for selected glaciers located in the Tien Shan and Pamir-Alay. A combination of three independent methods was 5 used to reconstruct for the past two decades the mass balance of the three benchmark glaciers, Abramov, Golubin and No.354. By applying different approaches, it was possible to compensate for the limitations and shortcomings of each individual method. This study proposes the use of transient snowline observations throughout the melting season obtained from satellite imagery and terrestrial automatic cameras. By combining modelling with remotely acquired information on summer snow depletion, it was possible to infer glacier mass changes for unmeasured years. Multi-annual mass changes based on high-10 accuracy digital elevation models and in situ glaciological surveys were used to validate the results for the investigated glaciers. balance modelling significantly narrows the uncertainty ranges of the estimates, and hence highlights the potential of the methodology for application to inaccessible glaciers at larger scales for which no direct measurements are available.

On the Automated Mapping of Snow Cover on Glaciers and Calculation of Snow Line Altitudes from Multi-Temporal Landsat Data

“…Comparing SLA values obtained by ASMAG with those derived manually [59] for Abramov Glacier in Kyrgyzstan revealed accuracies of nearly 90% (Figure 9). The only outlier in Figure 9a (red arrow) is due to clouds on the tongue of the glacier, which was classified as snow covering more than five elevation bins.…”

“…The ASMAG approach has also been applied to Abramov glacier in Kyrgyzstan to have a further independent measure of validation under different environmental conditions. We compared the results of ASMAG to manually digitized snowlines from Landsat satellite imagery [59] which were used to calibrate a mass balance model throughout the melting season. To achieve comparable results, we used the same glacier outlines, DEM and Landsat imagery as in this previous study.…”

The Aral Sea Basin

“…a -1 (2011-2016) and reconstructed mass balances confirmed the negative signal for the last decades for these glaciers (−0.30 to −0.43 m w.e. a -1 from 2000 to 2014; Barandun et al 2018;Barandun et al 2015;Hoelzle et al 2017;Kenzhebaev et al 2017;Kronenberg et al 2016). The first mass balance calculations reported moderate mass loss of −0.10 to −0.25 m w.e.…”

“…The MODSNOW-Tool is officially implemented in all five Central Asian countries (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan) and is currently used to improve seasonal river flow forecasts based on snow cover information obtained from remote areas (Apel et al 2018;Kalashnikova and Gafurov 2017). Besides MODIS and AVHRR optical remote sensing snow cover maps, LANDSAT snow cover maps with high spatial resolution (30 m) were used to reconstruct glacier mass balance in selected glaciers in the ASB (Barandun et al 2018;Kronenberg et al 2016). Satellite radar systems, e.g., Sentinel-1, are being tested for their capability to detect snow water equivalent (Conde et al 2019).…”

“…The reanalyzed historical glaciological measurements, reconstructed mass balance data and re-initiated in situ measurements provide a comprehensive and complete mass balance time series for Abramov, Golubin, Batysh Sook and Glacier No. 354 (Barandun et al 2018;Barandun et al 2015;Kenzhebaev et al 2017;Kronenberg et al 2016). Modern direct measurements revealed mass losses ranging from −0.25 to −0.51 m w.e.…”