40 research outputs found

    Impacts of climate change on river discharge in the northern Tien Shan: Results from long-term observations and modelling

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    This paper presents preliminary results of investigation of the observed and projected changes in discharge of the snow- and glacier-nourished rivers of the Balkhash-Alakol basin, Kazakhstan using the long-term homogeneous records and climate projections from an ensemble of climate simulations. Positive trends in discharge were registered at most sites between the 1950s and 2010s. An increase in discharge was observed at all sites between May and October in 2000 – 2013 in comparison with the previous decades which was particularly strong in July-August at the rivers with a high proportion of glacierized area. This positive trend in discharge appears to be driven primarily by an increase in temperature. Results for four climate scenarios with spatial resolution of 25 km are presented. These scenarios were generated using regional climate model PRECIS driven by HadGEM GCM for RCP 2.6 and RCP 8.5 scenarios, HadCM3Q0 and ECHAM5 GCM for A1B scenario. While all climate experiments project increase in temperature, precipitation projections vary between models, seasons and spatially. HBV-ETH model was used to simulate the observed and future discharge for the Ulken and Kishi Almatinka rivers using climate projections from PRECIS-HadCM3Q0 simulation for A1B scenario. The results show that peak flow has already been reached at both rivers and is likely to continue for the next 10-15 years. A small decrease of 7-10% in annual discharge is projected for the Ulken and Kishi Almatinka for the 2025-2044 period increasing thereafter and the projected decline in discharge is more significant in summer

    Chapter 8 The Status and Role of the alpine Cryosphere in Central Asia

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    The alpine cryosphere including snow, glaciers and permafrost are critical to water management in the Aral Sea Basin (ASB) and larger Central Asia (CA) under changing climate: as they store large amounts of water in its solid forms. Most cryospheric components in the Aral Sea Basin are close to melting point, and hence very vulnerable to a slight increase in air temperature with significant consequences to long-term water availability and to water resources variability and extremes. Current knowledge about different components of cryosphere and their connection to climate in the Basin and in the entire Central Asia, varies. While it is advanced in the topics of snow and glaciers, knowledge on permafrost it rather limited. Observed trends in runoff point in the direction of increasing water availability in July and August at least until mid-century and increasing possibility for water storage in reservoirs and aquifers. However, eventually this will change as glaciers waste away. Future runoff may change considerably after mid-century and start to decline if not compensated by increasing precipitation. Cryosphere monitoring systems are the basis for sound estimates of water availability and water-related hazards associated with snow, glaciers and permafrost. They require a well-distributed observational network for all cryospheric variables. Such systems need to be re-established in the Basin after the breakup of the Soviet Union in the early 1990s. This process is slowly emerging in the region. Collaboration between local operational hydro-meteorological services and academic sector, and with international research networks may improving the observing capabilities in high mountain regions of CA Asia in general and the ASB specifically
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