Hydrological forecasting based on remote sensing snow cover and glacier data in the river basins of the Tien Shan, Kyrgyzstan

Global warming in Central Asia has primarily led to glacier melting and the degradation of snow cover in mountainous regions. Research conducted by the Central Asian Institute of Applied Geosciences using Landsat data (2013–2016) revealed that glacier areas in the Tien Shan river basins have decreased by 10–47% compared to data from the USSR Glacier Catalog (1940–1970). Over approximately 70 years, Kyrgyzstan's glacier area has decreased by 16%, with large glaciers shrinking by 17%, while the area of small glaciers has increased by 2.5 times.

Field studies conducted on nine representative glaciers in Kyrgyzstan between 2011 and 2023 indicate a negative mass balance for glaciers in the mountain regions, with the exception of certain years for the Golubin Glacier (Ala-Archa River basin) and the Abramov Glacier (southern border of the Fergana Valley).

In addition to Landsat data, the dynamics of snow cover have been analyzed using MODIS data processed through the MODSNOW-Tool program. This tool provides valuable insights into snow cover dynamics and accumulation in the Tien Shan Mountains. Seasonal snow reserves and glacier runoff are the primary sources of water for mountain rivers in the Tien Shan. At altitudes above 2.5–3 km, melting in river basins lasts 5–6 months, contributing 80–90% of the annual runoff.

Snow cover data has also been utilized to forecast river flow in Kyrgyzstan. This forecasting methodology was developed under the Central Asia Water (CAWa) project and transferred to Kyrgyzhydromet for implementation in 2015. Over the past decade, it has been actively employed to predict water inflows into reservoirs. An evaluation of the methodology for the Naryn, Karadarya, Chu, and Talas rivers (2021–2023) demonstrated its high efficiency in operational hydrological forecasting.