Snow cover changes and affecting hydro-climate variables in Sabalan Mountainous region in Northwest Iran

Snow, a key part of the water balance in mountains, supports flow in snow-fed streams. This study aims to investigate snow cover variations and the effects of hydro-climatic variables on it in the Sabalan mountain region of Ardabil province, Iran. Snow cover changes were assessed through interpretation of Landsat satellite images. The Mann-Kendall test analyzed trends in temperature, precipitation, and discharge, while Pearson correlation assessed their relationship with snow cover. The results showed that snow cover decreased by ۱۲.۷% in the period between ۱۹۹۱ and ۲۰۰۳, and by ۶۵.۱% for the study period (۱۹۹۱-۲۰۱۵). Discharge had a decreasing trend in all hydrometric stations except Lay station in December, with significant reductions observed at Pole-Soltani and Nir hydrometric stations at ۹۹% and ۹۵% confidence levels, respectively. Additionally, Meshgin-Shahr hydrometric station showed an increasing trend in December discharge, while precipitation at Nir rain gauge station in January increased significantly. Although the temperature of both Meshgin-Shahr and Nir meteorological stations increased, correlation analysis did not identify a significant relationship between snow cover and hydro-climatic variables in the region. The study reveals a significant decline in snow cover in the Sabalan mountain region, with a ۶۵.۱% reduction from ۱۹۹۱ to ۲۰۱۵, indicating potential impacts on water availability. Despite rising temperatures and varying trends in precipitation and discharge, no strong correlation was found between snow cover and hydro-climatic variables. This suggests that other factors, possibly local microclimates or land use changes, may influence snow dynamics. The results revealed the complexity of snow-hydroclimate interactions and the need for integrated monitoring to manage future water resources.

کلیدواژه ها:

Discharge variation ، Mann-Kendall test ، River regime ، climate change ، snow cover