| Research on Lake Taihu's microclimate condition and local meteorological environment plays an important role in sustainable development of the surrounding cities and atmosphere macro-control. In order to simulate lake-air interaction in Lake Taihu more precisely. This study couple the CLM4-LISSS shallow lake land-surface process parameterization scheme to the Noah land-surface process model in WRF and evaluate the simulation performance of CLM4-LISSS shallow lake process scheme on the near-surface meteorological conditions in the region of Lake Taihu applying the data from the lake platforms and the land observing stations. Furthermore, on the base of coupled model simulation, this study analyze the effect of Lake Taihu on local climate. The results are as follows:(1) The lake surface temperature simulated by CLM4-LISSS lake land-surface process scheme can reflect the variation trend of real temperature. The simulated values of the three land surface processes at 2-m temperature also exist some difference.The mean Root Mean Square Error (RMSE) of 2-m temperature between CLM4-LISSSS lake land-surface scheme and observation value is 1.80?, which is better than CLM4.5 lake land-surface scheme (2.16?) and Noah default scheme (2.22?),the correlation coefficients between observation and both lake surface process scheme simulation are 0.88(CLM4-LISSS)?0.85(CLM4.5)?0.84 (Noah) .The 10-m wind speed mean RMSEs and correlation coefficients between observation and both lake surface process scheme simulation are 1.93m/s, 0.72 (CLM4-LISSS), 2.73 m/s, 0.68(CLM4.5), and 2.13m/s, 0.68 (Noah) respectively.(2) Lake Taihu has a significant impact on the meteorological environment of the surrounding cities. Lake Taihu surrounding area's near-surface temperature decreased 0.5-0.7? averagely at 3 pm in April and August. The range of influence is about 60km.The near surface temperature is increased 0.7-1? averagely at 6 a.m in August. The range of influence is about 50km. Lake Taihu surrounding area's near surface.temperature is decreased 0.3? averagely at 3 p.m in November. The range of influence is about 30km.Lake Taihu surrounding area's near-surface temperature decreased 0.5-0.7? averagely at 3 p.m. in Janurary and influence range is up to 50 km. Near-surface temperature increased 0.2 ? averagely at 6 a.m. in August and influence range is up to 10 km. The cold air brought by the lake winds suppresses the vertical movement of the urban heat island. Under the control of hot weather, the urban areas of Suzhou, Wuxi and Changzhou' s average PBL decreased 300m, 400m and 100m respectively in the daytime. The boundary layer' s maximum temperature decrease in the region of Wuxi can reach 0.5-0.7?.(3) By selecting stable weather as background conditions, this study analysis of the region's lake wind impact on urban heat island circulation. The result reflects that lake wind can disrupt the heat island circulation structure in the region of Wuxi, change the distribution of near-surface heat and water vapor, restrain the vertical development of urban heat island and affect the entire region of Wuxi in April and August.November lake circulation scale is small, which can only affect parts of Wuxi. There is no obvious lake circulation in January.The change of local thermal circulation may have a great impact on the local climate and the transport and diffusion of pollutants. The accurate parameterization scheme of lake land-surface process is significant for weather forecasting, air pollution simulation and climate simulation study. |
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