Concentration and correlation analysis of hydro-meteorological factors in the northern sub-basin of Lake Issyk-Kul in Central Asia

Abstract

This paper, based on the non-parametric tests and wavelet analysis, analyzed monthly precipitation and runoff data of the small basin in the northern part of the Lake Issyk-Kull basin over the nearly 62-year period, the concentration and correlation of precipitation and runoff in the small bowl of the north Lake Issyk-Kull basin. The results indicated that (1) the Cholpon-Ata River runoff (runoff 1) and the Chong-Ak-Suu River runoff (runoff 2) in the small watershed in the northern part of Lake Issyk-Kull basin are from June to April, January, and from September to November showed a significant increasing trend. The significant abrupt growth change occurred in 1983, while the precipitation at the Cholpon-Ata station showed a significant increasing trend in February, with a sharp point around 1980. (2) The concentration degree (Cd) index of runoff 1 in the small watershed in the northern part of the Lake Issyk-Kull basin has increased but not significantly, and the Cd index of precipitation and runoff 2 showed an insignificant decrease. (3) The Cd index of runoff 1 in the small watershed in the northern part of Lake Issyk-Kull basin existed for 10 years and 18 years, and the Cd index of River 2 existed for 9 years and 13 years. In contrast, the precipitation Cd index was significant at 4- and 15-year cycles. (4) On multiple time scales, they have a significant negative correlation between the runoff and precipitation in the small watershed in the northern part of the Lake Issyk-Kul basin from May to September.

Keywords

• Lake Issyk-Kul Basin
• Precipitation
• Runoff
• Wavelet analysis
• Correlation
• Concentration degree index