CLIMATE, SNOW COVER, GLACIERS, AND RUNOFF IN THE TIEN SHAN, CENTRAL ASIA¹

Abstract

The Pica Shan, a mountainous region located on the northern periphery of central Asia, has a wide range of climatic and hydrological conditions. On the basis of long term data from 348 meteorological and glaciological stations, the annual distribution of precipitation in different regions and elevational zones of the Tien Shan was calculated. Major climatic features are the entrance of moisture during spring‐summer, small winter precipitation, decrease of precipitation towards the east and the center of the mountains or with distance up valleys, and increase of precipitation with altitude up to crest‐lines of ranges. Annual total evaporation from snow can be 50–60 mm per year, reaching 30 percent of snow accumulation. Four main groups of rivers were identified: rivers with mainly snow nourishment, rivers with mainly glacial nourishment, rivers with mainly rain nourishment, and rivers with mainly ground water nourishment. Coefficient of runoff variation in Tien Shan's rivers is about 0.20, and coefficient of glacial runoff variation is about 0.15. Glacial runoff is 15–20 percent of the total volume of river runoff.

Re-establishing glacier monitoring in Kyrgyzstan and Uzbekistan, Central Asia

“…This observation is in line with the mass balance sensitivities of the glaciers in Central Asia as inferred by Rasmussen (2013). The observed cumulative mass balance determined by the glaciological method is supported by several remote sensing studies underlining the findings (Aizen et al, 1995b;Bolch et al, 2011Bolch et al, , 2012Pieczonka et al, 2013;Gardelle et al, 2013;Pieczonka and Bolch, 2015;Kronenberg et al, 2016).…”

“…There has been an extensive network of continuous long-term meteorological time series of air temperature and precipitation in Central Asian countries during the Soviet Union times (Aizen et al, 1995b). However, this network thinned out considerably during the recent past .…”

Mass balance observations and reconstruction for Batysh Sook Glacier, Tien Shan, from 2004 to 2016

“…The value for dT/dz. corresponds to the average monthly lapse rate for which melt is expected for the Central Tien Shan published in Aizen et al (1995). The lapse rate is held constant.…”

“…Daily precipitation totals and daily mean temperatures are calculated for the use as model input. Monthly temperature lapse rates calculated by Aizen et al (1995) from six stations in the Central Tien Shan are used to extrapolate the temperature data to the mean glacier elevation (Kronenberg et al, 2016).…”

Modelling and estimation of different components of streamflow for Gangotri Glacier basin, Himalayas / Modélisation et estimation des différentes composantes de l'écoulement fluviatile du bassin du Glacier Gangotri, Himalaya

“…Air temperature correlates well with several energy balance components, hence it is the most commonly used index, but other variables such as net radiation, wind speed, vapour pressure and solar radiation are also used. Studies have shown that temperature index or degree-day models are the most widely used approaches for runoff computation from glacierized basins (Aizen et al, 1995;Rango & Martinec, 1995;Semadeni-Davies, 1997;Hock, 2003).…”