Modeling the Impacts of a Man-Made Lake on the Meteorological Conditions of the Surrounding Areas

The possible modifications of the surface meteorological conditions due to construction of a small, man-made lake in midlatitudes (surface area of 11.55 km² and maximum fetch distance L ≈ 5 km) were investigated using the Weather Research and Forecasting (WRF) model (version 3.3). The model was applied to four real typical synoptic situations for which the area of interest was under the influence of a wintertime anticyclone (WA), a wintertime cyclone (WC), a summertime anticyclone (SA), and a summertime cyclone (SC). Each of these four typical synoptic setups was simulated twice—once assuming the present state (“NO-LAKE” experiment) and again assuming the existence of the new lake (“LAKE” experiment). The differences between 36-h average LAKE and NO-LAKE simulation results show noticeable mean changes in the surface temperature and relative humidity as well as a small increase of the mean surface wind speeds in the air above the newly constructed lake. At other portions of the investigated area (distances up to ~4L– 6Ldownstream of the new lake), the 36-hmean differences produced by the new lake are below the order of magnitude of accuracy of operational meteorological measurement instruments. In individual hours, however, these differences are occasionally very high, particularly for cyclonic episodes. In addition, results obtained for SA suggest an existence of a lake circulation cell associated with small differences between the lake and land temperatures (at most up to ~3°–5°C) and consequently, a slight enhancement of slope winds in future (LAKE) conditions.