Erdenechuluun, Ariuntsetseg1st Supervisor: Prof. Dr. Gantuya Ganbat2nd Supervisor: Prof. Dr. Jambajamts Lkhamjav2026-11-032026-05Student ID: B2200057https://gmitlibrary.net/handle/123456789/232Urban greening is widely promoted as a nature-based remedy for urban overheating, yet its microclimate response in cold, semi-arid, mountain-bounded capital cities such as Ulaanbaatar differs fundamentally from the linear cooling reported in humid climates. The Weather Research and Forecasting model coupled to the Single-Layer Urban Canopy Model was configured in four nested domains down to 1 kilometer over Ulaanbaatar, driven by ERA5 reanalysis. Four scenarios were simulated for 22 June 2025 by modifying the urban impervious-area fraction (FRC_URB) at 1.0, 0.9, 0.5, and 0.1, corresponding to greening levels of 0, 10, 50, and 90 percent. The 0.9 case was retained as the control. The control reproduced the tropospheric temperature profile with a root-mean-square error of 1.2°C and a nocturnal urban heat island of 2.5°C, matching the long-term observed summer mean. The daytime response was moisture-dominated: a shift from 0 to 90 percent greening lowered the 2 m air temperature by only 0.3°C but raised the surface dew point by 1.8°C. The nocturnal urban heat island declined monotonically with greening fraction and reversed sign at the strongly greened limit, falling from 3.5°C through 0.6°C at moderate greening to −2.9°C at 90 percent greening, driven by reduced heat-storage release and weakened surface roughness that allowed katabatic drainage to ventilate the basin. The −2.9°C value is an upper bound sensitive to the model soil-moisture treatment. Intermediate rather than maximum greening minimizes the nocturnal urban heat island in a basin-confined city, and the full cooling potential is realized only when greening is combined with irrigation, permeable surfaces, and rainwater harvesting.enUrban Heat IslandUrban greeningGreening sensitivityUlaanbaatarWRF modelSLUCMThesisBachelor's Thesis, Environmental Engineering, Faculty of Raw Materials and Environmental Engineering, German-Mongolian Institute for Resources and Technology (GMIT), Ulaanbaatar/Nalaikh, 2026. Student ID: B2200057. 1st Supervisor/Examiner: Prof. Dr. Gantuya Ganbat; 2nd Supervisor/Examiner: Prof. Dr. Jambajamts Lkhamjav.