Accelerated Glacier Area Loss in the Zhetysu for the Period of 1956–2016

An updated glacier inventory is important for understanding the current glacier dynamics in the conditions of actual accelerating glacier retreat observed around the world. Here, we present a detailed analysis of the glaciation areas of the Zhetysu Alatau Range (Tien Shan) for 1956-2016 using well-established semiautomatic methods based on the band ratios. The total glacier area decreased by 49 ± 2.8% or by 399 ± 11.2 km[sup.2] from 813.6 ± 22.8 km[sup.2] to 414.6 ± 11.6 km[sup.2] during 1956-2016, while the number of glaciers increased from 985 to 813. Similar rates of area change characterized the periods 1956-2001, 2001-2012, 2012-2016, and 2001-2016: −296.2 ± 8.3 (−0.8% a[sup.−1]), −63.7± 1.8 (−1.1% a[sup.−1]), −39.1 ±1.1 (−2.2% a[sup.−1]) and −102.8 ± 2.9 (−1.3% a[sup.−1]) km[sup.2], respectively. The mean glacier size decreased from 0.57 km[sup.2] in 2001 to 0.51 km[sup.2] in 2016. Most glaciation areas of the Zhetysu Alatau faced north (north, northwest, and northeast), covered 390.35 ± 11 km[sup.2], and were located in altitudes between 3000 and 4000 m.a.s.l. With shrinkage rates of about −0.8% and −1.3% a[sup.−1] for the periods of 1956-2001 and 2001-2016, our results show that study area has the highest shrinkage rate compared to other glacierized areas of Central Asian mountains, including Altai, Pamir, and even the inner ranges of Tien Shan. It was found that a significant increase in temperature (0.12 °C/10 years) plays a main role in the state of glaciers.