Implications of elevation-dependent warming to water resources over the Chinese Qilian Mountains

Abstract

Warming in mountainous regions has experienced obvious elevation dependence (the warming rate of air temperature is amplified with elevation), which accelerates the melting of ice and snow, affecting glacier size and mass, and water resources in mountainous regions. Here, we used ERA5-Land monthly averaged datasets from 1979 to 2019 to analyze the elevation-dependent warming (EDW) variability, driving factor, and its implications to water resources in the Qilian Mountains (QLM). Results showed that: (1) Annual mean temperature shows a significant increasing trend in the QLM from 1979 to 2019 (0.31 °C/10a; p < 0.01), and the warming rate of annual mean temperature increased with elevation in the QLM in general. For seasonal scales, the most obvious EDW was found in summer. In the past 41 years, snow cover and snow depth showed a slight decreasing trend. There was a significant negative correlation between temperature and snow cover, which can explain that enhanced regional warming has caused decreases in snow cover and snow depth, largely controlling the pattern of EDW on the QLM. EDW has significant implications for water resources over QLM, especially above 5,000 m. Our study can provide a reference in understanding the importance of EDW to water resources in mountainous areas. HIGHLIGHTS ERA5-Land reanalysis 2 m temperature data are reliable in Qilian Mountains.; There is an obvious elevation-dependent warming (EDW) of annual mean temperature, especially above 5,000 m.; Snow cover in Qilian Mountain showed a decreasing trend.; Snow cover is an important mechanism driving EDW.; EDW has an important implication for water resources (especially above 5,000 m).;

Keywords

• elevation-dependent warming
• era5-land reanalysis
• qilian mountains
• snow cover
• water sources