Spatio‐temporal changes in precipitation, temperature and their possibly changing relationship: a case study in the Wei River Basin, China

Abstract

ABSTRACTWith the purpose of further understanding the spatio‐temporal changes in precipitation, temperature and their possibly changing relationship in the Wei River Basin (WRB), a typical arid and semi‐arid region in China, the modified Mann–Kendall (MMK) test method was used to capture their trends at monthly and annual time scales, and the K‐means cluster analysis method was applied to divide the whole basin into three homogeneous sub‐regions. Furthermore, a copulas‐based method was introduced in this study to identify possible inflection points of the relationship between precipitation and temperature in the WRB. Results indicate that: (1) spatially, both annual average precipitation and temperature decreased from southeast to northwest; temporally, for most months, a decreasing trend was found for precipitation while the air temperature in most months has a significantly increasing trend at 99% confidence level at monthly and annual time scales in the WRB; (2) climate warming has less effect on the precipitation structure than that on the precipitation magnitude in the WRB; and (3) overall, the relationship between precipitation and temperature in the whole WRB has no significant inflection point, implying a relatively stable relationship between precipitation and temperature changes. This study provides a new idea and quantitative measure for the identification of inflection points of the relationship between precipitation and temperature.