Sea breezes are one of the most important weather processes affecting the environmental and climatic features over coastal areas, and the sea breeze from the Pearl River Estuary (PRE) has significant effects on the Pearl River Delta (PRD) region. We simulated a typical sea breeze process that occurred on 27 December 2020 in the PRD region using the Weather Research and Forecasting (WRF) model to quantify the effects of topography and city clusters on the development of the sea breeze circulation. The results show that: (1) the topography on the west coast of the PRD tends to block the intrusion of the sea breeze and detour it along the eastern part of the terrain in the southeast of Jiangmen. The depth of sea breeze along the position of the detour is increased by 120 m, the penetration distance is increased by 40 km, the maximum intensity of sea breeze decreases by ~0.4 m/s, and the time of maximum speed delays for 4 h. However, on the east coast, the topography promotes the sea breeze, resulting in an occurrence about 4 h earlier due to the heating effects. The depth and the speed of the sea breeze are increased by 466 m and 1.2 m/s, respectively. (2) Under the influence of Urban Heat Island Circulation (UHIC), the sea breezes reach cities near the coast an hour earlier and are later inhibited from propagating further inland. Moreover, a wind convergence zone with a speed of 3–5 m/s and a width of about 25 km is formed along the boundary of suburbs and cities in the PRD region. As a result, two important convergence areas: Foshan–Guangzhou, and Dongguan–Shenzhen are formed. (3) Overall, the topography has a more remarkable impact on the mesoscale wind field especially in the mountain and bay areas, resulting in an average speed disturbance of 2.8 m/s. The urban heat island effect is relatively small and on average it causes only ± 0.9–1.8 m/s wind speed perturbations in the periphery of two convergence areas and over PRE.

The micrometeorological elements, radiation budget, and surface energy distribution at four sites with land cover types of vegetable, orchard, maize, and desert in the Heihe River basin (HRB) from June 2012 to September 2012 are compared to investigate the differences in the land–atmosphere interaction between different surface types and the biophysical effects of land use and land cover change on surface temperature. The desert site has the highest soil surface temperature during both daytime and nighttime. The strongest cooling effects of maize, orchard, and vegetable are −20.43, −19.35, and −16.42 K, respectively, during daytime, and the average cooling effects are −1.38, −2.52, and −0.93 K, respectively, at nighttime. The differences in the surface cooling effects of the non-desert sites relative to the desert are attributed to the differences in albedo and incoming shortwave radiation, emissivity and incoming longwave radiation, sensible heat flux, latent heat flux, and soil surface heat flux, according to the direct decomposed temperature metric theory. The radiation terms have negative feedbacks on the cooling effects in the non-desert sites. Latent heat flux plays a key role in the differences in the surface temperature among the four sites during both daytime and nighttime, and the soil surface heat flux is also a main factor at night.