Sensitivity Analysis of the High-Resolution WISE-WRF Model with the Use of Surface Roughness Length in Seoul Metropolitan Areas

Abstract

In the numerical weather model, surface properties can be defined by various parameters such as terrain height, landuse, surface albedo, soil moisture, surface emissivity, roughness length and so on. And these parameters need to be improved in the Seoul metropolitan area that established high-rise and complex buildings by urbanization at a recent time. The surface roughness length map is developed from digital elevation model (DEM) and it is implemented to the high-resolution numerical weather (WISE-WRF) model. Simulated results from WISE-WRF model are analyzed the relationship between meteorological variables to changes in the surface roughness length. Friction speed and wind speed are improved with various surface roughness in urban, these variables affected to temperature and relative humidity and hence the surface roughness length will affect to the precipitation and Planetary Boundary Layer (PBL) height. When surface variables by the WISE-WRF model are validated with Automatic Weather System (AWS) observations, NEW experiment is able to simulate more accurate than ORG experiment in temperature and wind speed. Especially, wind speed is overestimated over 2.5 m s −1 on some AWS stations in Seoul and surrounding area but it improved with positive correlation and Root Mean Square Error (RMSE) below 2.5 m s −1 in whole area. There are close relationship between surface roughness length and wind speed, and the change of surface variables lead to the change of location and duration of precipitation. As a result, the accuracy of WISE-WRF model is improved with the new surface roughness length retrieved from DEM, and its surface roughness length is important role in the high-resolution WISE-WRF model. By the way, the result in this study need various validation from retrieved the surface roughness length to numerical weather model simulations with observation data.

High-resolution urban observation network for user-specific meteorological information service in the Seoul Metropolitan Area, South Korea

“…The surface roughness and displacement lengths are obtained by a micrometeorological method and verified with those obtained from urban morphology data such as mean building height, frontal area density, and plane area density from the geographical information system (Macdonald et al, 1998;Kwon et al, 2014). They are expected to produce high-resolution surface property maps, such as albedo, emissivity, and thermal conductivity, and surface roughness length and displacement (Yi et al, 2015;Jee et al, 2016). Furthermore, they determine the 30 min averaged carbon dioxide concentration and flux and the sensible heat flux, latent heat flux, radiative flux, and heat storage.…”

Impact of Roughness Length on WRF Simulated Land‐Atmosphere Interactions Over a Hyper‐Arid Region

“…The roughness length, a crucial parameter for land-atmosphere interactions (e.g., Jee et al, 2016;June et al, 2018;Reijmer et al, 2004), is defined as the height above the surface at which the horizontal wind speed is zero, assuming that its variation in the surface layer follows a logarithmic profile (e.g., Jiménez et al, 2012). Empirically, z 0m is estimated as being about 1/10th of the height of the roughness elements (e.g., Wallace & Hobbs, 2006), but its representation in numerical models is challenging given the land surface heterogeneity within a model grid-box.…”

“…By using an updated zero-displacement plane and aerodynamic roughness length values, roughly three times larger than the default considered in WRF, for a sea breeze event in Tokyo in September 2011, Varquez et al (2015) reported a much improved simulation of the near-surface horizontal wind speed. Jee et al (2016) stressed that the use of a realistic roughness length over Seoul leads to an improvement of the friction velocity, wind speed, temperature and relative humidity predictions, and ultimately the model precipitation and Planetary Boundary Layer (PBL) depth forecasts. The papers referred above highlight the important role of the surface roughness length, not just on the prediction of surface and near-surface fields but also on the forecast of the PBL depth.…”

High-Resolution Urban Observation Network for a User-Specific Meteorological Information Service in the Seoul Metropolitan Area, Korea

“…The surface roughness and displacement lengths are obtained by a micrometeorological method and verified with those obtained from urban morphology data such as mean building height, frontal area density, and plane area density from the geographical information system (Macdonald et al, 1998;Kwon et al, 2014). They are expected to produce high-resolution surface property maps, such as albedo, emissivity, and thermal conductivity, and surface roughness length and displacement (Yi et al, 2015;Jee et al, 2016). Furthermore, they determine the 30 min averaged carbon dioxide concentration and flux and the sensible heat flux, latent heat flux, radiative flux, and heat storage.…”

“…Park et al, 2011S.-U. Park et al, , 2013Jeong and Park, 2013). The western part of the SMA comprises relatively low-lying farmland or urban areas, while the eastern part contains high-altitude mountain ranges, some of which are higher than 1000 m in Domain 1 (Fig.…”