A significant increasing trend (p < 0.01) was detected for the annual runoff and monthly runoff (May to September p < 0.01). The results showed that the glacier area has decreased by 13% and the total volume has decreased by 0.018 km3 over the past four decades. The hydrological processes were also simulated through the HBV-light model to quantify the impact of climate change on the glacier and runoff.
#Corona weather 9288 series
This study investigated the glacier change (area, surface elevation and volume change) and analyzed the variation of the observed runoff series over the past four decades in the Yushugou Basin, Eastern Tianshan Mountains. The impact of climate change on glaciers and the hydrological processes in the easternmost end of the eastern Tianshan Mountains has yet to be understood. This study reveals unused opportunities for expanding existing land-use change analysis back to the 1940s in data-scarce environments. Urban growth rates are 10- to 26-fold, while growth into flood exposed areas ranges from 2- to 100-fold. A change assessment from 1948 to 2020 is conducted by aerial images, declassified satellite images, and recent data. Therefore, the study compares urban growth into hazard areas in urban rims of Nairobi and Nyeri, Kenya.
The results are of interest to other locations in Kenya and worldwide, too, since the current research and disaster risk practice focus is still too much on megacities and city centres. While Nairobi as the capital and principal city has been extensively analysed regarding urban growth and flood hazard in some central parts, awareness of growing peri-urban areas has not been studied as much. Kenya experiences massive urban growth, also into natural hazard-prone areas, exposing settlements and the natural environment to riverine and pluvial floods and other natural hazards. Regarding altitude, the termini of glaciers rose continuously from 1990 to 2015, particularly for glaciers below 3700 m, with a total area decrease of 30.37%, and the lower altitude of the glaciers showed a higher area decrease. All aspects in the northern Tien Shan exhibited negative trends in the glacier area, especially in the east–west aspects (shrinkage of 24.74–38.37%). Glaciers in the outer northern Tien Shan region, with areas < 2 km2 showed the greatest shrinkage, especially those in the northeastern and southwestern regions. The reduction in the total glacier area exhibited an accelerating trend, decreasing by 0.60%/a before 2000, but by 0.71%/a after 2000. The results showed that the total area and volume of glaciers in the northern Tien Shan exhibited negative trends, decreasing by 456.43 km2 (16.08%) and 26.14 km3 (16.38%), respectively.
This study investigated the spatiotemporal dynamics of glaciers in the northern Tien Shan from 1990 to 2015 using multi-source remote sensing and meteorological data. Research on glaciers is important for the sustainable development and management of water resources in Central Asia. The Tien Shan is regarded as the “Water tower of Central Asia,” being a solid reservoir of freshwater resources and also a natural and early warning indicator of climate change. The observed accelerated glacier shrinkage is expected to have two impacts on the more populated outer ranges: 1) water shortages during summer and 2) increased threat from glacier hazards such as glacier lake outburst floods (GLOFs) and ice avalanches.
Regional differences of glacier-area changes related to local climate conditions, to the altitudinal distribution of glacier areas, and to the relative proportion of glaciers in different size classes. Recent glacier area loss has resulted from rising summer temperatures. The most dramatic glacier shrinkage has occurred in the outer ranges of the Tien Shan Mountains. Glacier behavior has varied markedly in these regions. In the last 7 years (~ 2000 to ~ 2007), glacier area shrank by 5% in the Pskem region, 4% in the Ili-Kungöy region, 4% in the At-Bashy region, and 0% in the SE-Fergana region. Over the 30 years investigated between ~ 1970 and ~ 2000, glacier area decreased by 19% in the Pskem region, 12% in the Ili-Kungöy region, 12% in the At-Bashy region, and 9% in the SE-Fergana region.
The four mountain regions investigated (Pskem, Ili-Kungöy, At-Bashy, and SE-Fergana) cover several distributed glacierized areas in the Tien Shan Mountain system, a region that is affected by highly variable local precipitation regimes. Geographic variability of the recent changes of glacier coverage in the Tien Shan Mountains, Central Asia, is assessed using Corona KH-4B satellite photographs for 1968–1971, Landsat 7 ETM+data for 1999–2002, and ALOS/PRISM and AVNIR data for 2006–2008.
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