To study the problem about how to incorporate the anthropogenic heat flux into the model, we simulate some cases using the Regional Boundary Layer Model developed by Nanjing University (NJU-RBLM) in different cities and different seasons. The simulated results show that the best scheme of including anthropogenic heat flux into the PBL model is to account for the urban canopy heating terms both in the surface energy budget and in the atmospheric heat conservation equation with certain proportions. Results of sensitivity tests about changing the value of the anthropogenic heat flux show that anthropogenic heat flux plays an important role in the urban heat environment. The contribution of anthropogenic heat to UHI is 29.6% with Nanjing anthropogenic heat data in 2002. When heat emission doubles, it reaches 42.9%. The anthropogenic heat emission has impacts on PBL inversion structure during the morning and the intensity of UHI cyclone, and it could results in a 0.5~1.0°C surface temperature increase at night.

The middle and lower reaches of the Yangtze River (MLYR) frequently experience extreme precipitation events (EPEs) during June and July, the so-called Meiyu season. This study investigated EPEs in the MLYR during Meiyu seasons over 1961–2022, using rain gauge observations and ERA5 reanalysis data. EPEs associated with the Northeast China cold vortex featured more undulating westerlies with a distinct wave train pattern from Europe to Northeast Asia. Due to robust Rossby wave energy, the trough deepened from Northeast China towards the MLYR and was confronted with a westward extension of the western Pacific subtropical high. Such a configuration enhanced the warm and moist monsoon conveyor belt and convergence of water vapor flux from southwestern China to the MLYR. The warm and moist air favored upward motion. The increased rainfall prevailed from southwestern China to the MLYR. In contrast, ordinary EPEs were characterized by zonal westerlies and weaker Rossby wave propagation. The Meiyu trough was comparatively shallow and confined to the MLYR with less westward expansion of the subtropical high. In response, the warm and moist monsoon conveyor belt was more localized, resulting in weaker EPEs in the MLYR.