Abstract
The large population growth has significantly altered the thermal characteristics of the atmosphere, including decreased albedo and increased heat capacity; thus, urban areas experience unique climatic phenomena. We conducted sensitivity experiments using Unified Model Local Data Assimilation and Prediction-Met-Office-Reading Urban Surface Exchange Scheme (LDAPS-MORUSES) to investigate the response of surface energy budget to albedo changes in the Seoul Metropolitan Area. We compared 1.5-m temperature at 56 automatic weather station (AWS) sites and showed underestimations of approximately 0.5–2 K, but the diurnal cycle was well simulated. We changed the wall and road albedo parameters by ±50% from the default values for sensitivity experiments. With increasing albedo, 1.5-m temperature decreased by approximately 0.06 °C and 0.01 °C in urban and suburban areas, respectively. These changes are responses to decreased net radiation and sensible heat during daytime, whereas sensible heat mainly contributes to the surface cooling during nighttime. Furthermore, the decrease in albedo leads to altered vertical structure of potential temperature and atmospheric circulations at altitudes of 300–1000 m. Results show that albedo modification can affect not only surface temperature but also the entire urban boundary layer.
Highlights
Urban areas are characterized by dense populations and artificial structures, which give them a unique climate
The unique climate can be manifested through several phenomena, such as urban heat islands, in which artificial structures absorb shortwave radiation during the daytime and release longwave radiation at night
The changes in the shortwave radiation caused by albedo alter the surface energy balance, which in turn reduces surface temperature
Summary
Urban areas are characterized by dense populations and artificial structures, which give them a unique climate. Previous study reported a change in albedo on the roofs, walls, and pavement in the Sacramento using Weather Research and Forecasting-Chemistry (WRF-Chem) model, resulting in decrease in air temperatures, PM2.5 and ozone concentration [4]. Met-Office-Reading Urban Surface Exchange-Scheme (MORUSES) separates a single tile into roofs and canyons, forming walls, roads, and roofs, for which parameters such albedo and emissivity can be changed. These two factors are used to calculate shortwave radiation, longwave radiation, sensible heat, latent heat, and ground heat [11].
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call