HR: 09:30h
AN: A41E-07    [Abstracts]
TI: Microscale Analysis of Surface Wind Variability by Resolving Small-Scale Terrain Features in High-Resolution Simulations
AU: * Takemi, T
EM: takemi@storm.dpri.kyoto-u.ac.jp
AF: Kyoto University, Gokasho, Uji, 6110011, Japan
AU: Hatamura, S
EM: s_hatamura@hotmail.com
AF: Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, 2268502, Japan
AB: The temporal and spatial variability of surface winds is a critical information in predicting the transport of atmospheric tracers and pollutants, operating wind energy power plants, and evaluating atmospheric environment in urban areas where deteriorating factors such as heat island phenomenta are significant. These surface wind analyses are required especially in areas with complex terrain and land-use characteristics. Although general meterological conditons can be evaluated by the current regional-scale simulations with a grid spacing of O(1 km) to O(10 km), the evaluation of surface winds that are sensitively affected by small-scale features of terrain and land use is relatively poor. In this study, we investigate the temporal and spatial variability of surface winds in the microscale by conducting high-resolution simulations with small-scale terrain features being well-resolved. A mesoscale meteorological model MM5 is used for the simulations in multi-nested mesoscale domains with a minimum grid spacing of 111 m in the finest-mesh domain. The area of interest is a Japanese peninsula whose size is about 30 km by 10 km projecting into the Pacific Ocean. A variety of simulations are conducted for a one-year period and the six-months periods of summer (JJA) and winter (DJF). In coarse-mesh (i.e., 1 km) runs examining the effects of boundary-layer mixing parameterizations, the sensitivity to stability is examined in different seasons and in different meteorological settings. With a best choice of the parameterization, 111-m mesh simulations are conducted and compared with the coarse-mesh results. Small-scale and short-term variabilities of surface winds are reproduced with the fine-mesh simulations. As the spatial variability of terrain elevations increases, the variability of wind speeds increases especially under weak-wind conditions. Resolving representative scales of terrain is important in predicting microscale features of surface winds.
DE: 3307 Boundary layer processes
DE: 3309 Climatology (1616, 1620, 3305, 4215, 8408)
DE: 3329 Mesoscale meteorology
DE: 3355 Regional modeling
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting