Interplay Between Urbanization and Irrigation on Summer Climate in the Huang‐Huai‐Hai Plain, China.

This study investigates how the individual and combined effects of urbanization and irrigation affect summer climate using convection‐permitting regional climate model simulations with/without urbanization or irrigation over the Huang‐Huai‐Hai plain (3HP). We found that (a) In dramatic urban expansion areas, T2max, T2avg, and T2min increased by 0.53, 0.43, and 0.40°C, respectively. Urbanization influenced the net radiation (RN), sensible heat flux (H), latent heat flux (LE), and ground flux (GF) by 1.08, 9.58, −10.69, and 0.59 W/m2 (b) Over the irrigated area, T2max, T2avg, and T2min significantly decreased by −1.50, −1.30, and −1.16°C. The RN, LE significantly increased by 10.06 W/m2, 28.40 W/m2, while H and GF decreased by 19.44 and 1.19 W/m2. (c) The combined effect of urbanization and irrigation decreased T2max, T2avg, and T2min by −0.84, −0.77, and −0.71°C. The RN, LE significantly changed by 4.93 and 27.84 W/m2, while H and GF declined by 18.65 and 1.28 W/m2. (d) Urbanization significantly decreased the total precipitation by 0.04 mm/day, while irrigation and the combined effect increased the total precipitation by 0.12 and 0.16 mm/day. Urbanization and irrigation have more influence on the extreme precipitation than on the summer mean precipitation. (e) Specific humidity (Q) changes at high altitude (>2 km) are mainly controlled by thermodynamic changes, while at a low level, Q changes depended on the evapotranspiration, sea‐land breeze, and surface roughness. Key Points: The individual and combined impacts of urbanization and irrigation on summer climate were investigated using ALARO‐SURFEX firstly over 3HPUrbanization reduced rainfall by decreasing convective precipitation, while irrigation enhanced convective and large‐scale precipitationUrbanization has accelerated the warming tendency while irrigation processes have delayed the temperature trend to some extent [ABSTRACT FROM AUTHOR]