Numerical simulations on micro-meteorological changes caused by the weir construction using WRF-LES

Micro-meteorological changes sometimes bring an important effect in social and economic activities of human beings. One of the main factors breaking out the changes is the large scale civil engineering works such as weir or dam construction. Recently, multi-purpose weirs were constructed on the Nakdong River in the Korean Peninsula. In this study, The local meteorological circulation over Nakdong River was investigated using mesoscale model WRF-LES (Large Eddy Simulation mode of Weather Research and Forecasting model) developed by NCAR (National Center for Atmospheric Research), in order to study local meteorological changes due to change in Nakdong River water system. WRF-LES which has a 333-m horizontal resolution was conducted sensitivity experiment on the change of landuse and validated with NIMR (National Institute of Meteorological Research) AWS and KMA(Korea Meteorological Administration) AWS data. Numerical simulation on micro-meterological changes shows that temperature decreases in the afternoon and increases in the early morning near the river. and Urban heat island effect over Daegu is weakened with expansion of river width. and The horizontal thermal contrast induced by Nakdong River, during daytime, is negative. At night-time, The horizontal thermal contrast induced by Nakdong River is positive. When the river is extended, the thermal contrast induced is stronger. and Nakdong River is able to generate and sustain a River breeze, which is formed around 09 LST and reaches maximum intensity 13 LST. and the numerical simulations have shown that land use effect is important in the spatial distribution of the River-breeze circulation. river breeze is strengthened with expansion of river width. We have noticed that temperature and local circulation changes by increase in water area and the results from this research will help study the meteorological impact assessment of the landuse change due to environmental development.