Mass balance reconstruction for Shiyi Glacier in the Qilian Mountains, Northeastern Tibetan Plateau, and its climatic drivers

Abstract

Based on glacio-meteorological records, 7 years of in-situ mass balance data, and a temperature-index model, the long-term annual and seasonal mass balances of Shiyi Glacier in the northeast Tibetan Plateau (TP) were reconstructed from 1963/64 to 2016/17. Variations were then linked to local climatic and macroscale circulation changes. The model was calibrated based on in-situ mass balance data and was driven by daily air temperature and precipitation data recorded at nearby alpine meteorological stations. The results show that the reconstructed annual mass balance experienced an overall downward trend over the past 54 years, with a remarkably high mass loss rate during 1990/91-2016/17. Analysis of mass balance sensitivity and local climatic changes shows that the pronounced mass loss since the 1990s can be mainly attributed to cumulative positive temperature increases caused by air temperature increases and prolongation of the ablation season. From the perspective of macroscale circulation, the reconstructed annual mass balance values correlate well with zonal wind speeds (June to September) in the glacierized region. For the positive/negative phase of the annual mass balance, an inverse spatial pattern in relation to geopotential height change (low/high-pressure centres) and corresponding conversion of cyclonic/anti-cyclonic circulation were present in northern hemisphere mid-latitudes. Comparative analysis of existing long-term mass balance series over the TP indicates that asynchronous climatic changes in the different glacierized regions led to inconsistent interannual fluctuations in glacier mass balance.

The Evolution of the Glacier Surges in the Tuanjie Peak, the Qilian Mountains

“…This is consistent with the recorded increase in summer precipitation since the mid-1990s in the Inner Tibetan Plateau due to the weakening of the Westerlies [71]. Compared with other parts of the QLMs, the forcing mechanism must favor greater accumulation [72]. Over time, the accumulation zone will accept more ice mass-as a result, the bottom part of the glacier may reach the pressure melting point, which produces meltwater and causes glacier sliding to occur [73].…”

Possible Causes of Anomalous Glacier Mass Balance in the Western Kunlun Mountains

“…This phenomenon is more significant in the ablation season (Figure S5 in Supporting Information ). Under these conditions, ablation‐season meltwater can be higher than annual snowfall for these glaciers, such as at Parlung No.4 Glacier (Zhu et al., 2018a) and glaciers in Hailuogou catchment (Y. Zhang et al., 2015) in southeastern TP, Zhadang Glacier (Zhu et al., 2018a) in the southern TP, glaciers in the central Himalayas (Bonekamp et al., 2019), Naimona'nyi Glacier on a north‐facing slope in the western Himalayas (Zhu, Yang, et al., 2021) and Shiyi Glacier in the northeastern TP (H. Zhang et al., 2021). Overall, the mean mass balance for these glaciers outside the WKM was negative during 2000–2010s (Brun et al., 2017; Zhu, Yang, et al., 2021), accompanied by low ablation‐season albedo (Zhu et al., 2018a).…”

“…Under these conditions, ablation-season meltwater can be higher than annual snowfall for these glaciers, such as at Parlung No.4 Glacier (Zhu et al, 2018a) and glaciers in Hailuogou catchment (Y. Zhang et al, 2015) in southeastern TP, Zhadang Glacier (Zhu et al, 2018a) in the southern TP, glaciers in the central Himalayas (Bonekamp et al, 2019), Naimona'nyi Glacier on a north-facing slope in the western Himalayas and Shiyi Glacier in the northeastern TP (H. Zhang et al, 2021).…”

Mass Balance Reconstruction for Laohugou Glacier No. 12 from 1980 to 2020, Western Qilian Mountains, China

“…The Qilian Mountains (QM) are a main glaciation area in China with an arid climate, whose glacier meltwater is crucial for local natural environment [12], but a half-century of glacier melting on the QM has intensified [13,14]. Glacier mass balance (MB) is an important index to measure glacier change [15]. In alpine regions, long-term MB observations are scarce.…”

“…In alpine regions, long-term MB observations are scarce. In recent years, in situ measurements, glacier melting models [15][16][17], and remote sensing images [18][19][20] have been widely used to study glacier changes. However, in situ measurements are subject to severe weather, while remote-sensing images are time period-limited.…”