Weekend effect of summer temperature in Chongqing the Municipality of Western China

Abstract Human activities have obvious weekly cycle characteristics(so-called weekend effect), the impact of it on local or large-scale atmospheric circulation and climate, especially temperature. If it can be detected that meteorological elements have a weekly cycle, it can reflect the impact of human activities on climate. In the present study, the weekend effect of summer temperature in Chongqing༈the municipality of Western China༉for the period 1961–2021 was analyzed. Results showed that the weekly variation of summer temperature in Chongqing is mainly negative weekend effect༈i.e., lower temperature on weekends compared to weekdays༉. Taking 1997 as the boundary, the difference of weekend climate effect before and after warming was analyzed. This study indicated that there is spatial consistency in the weekend effect of summer temperature in Chongqing, and the intensity of weekend effect in most areas is significantly enhanced after warming. Urbanization, aerosols and other meteorological elements have been analyzed and discussed to explain the weekend effect of summer temperature in Chongqing, with the acceleration of regional warming and urbanization, the emission of aerosols in weekdays was more than that in the weekend. First, the role of aerosols in heating the atmosphere on weekdays was greater than that in the weekend; Second, the weakening of the atmosphere heated by aerosols leads to more clouds on weekend than on weekdays, and the solar radiation received by the ground decreases; Third, the frequency of precipitation on weekdays was less than that on weekend. The three factors were conducive to the temperature higher on weekdays than on weekend.