Estimating the Effects on the Regional Precipitation Climate in a Semiarid Region Caused by an Artificial Lake Using a Mesoscale Model

The effects on the regional precipitation climate by the construction of an artificial lake, in a semiarid region are studied. The study is performed using a mesoscale model to identify the larger-scale meteorological conditions when precipitation enhancement is to be expected and to estimate the amount of precipitation enhancement in such situations. The model results are combined with a ten-year synoptic observations dataset to estimate the mean annual increase in precipitation for the region. The results show a significant increase in precipitation partly over the artificial lake itself, due to land/sea-breeze type circulations during periods when the large-scale wind is weak and the surface temperature of the sea is higher than that of the surrounding areas, and partly over the mountains north of the area in cases with sufficiently strong southerly winds causing the air to be lifted. Being aware of the uncertainty in the quantitative estimates presented here, this paper shows how a combination of mesoscale model “sensitivity runs” and climatological data can be used to estimate at least the order of magnitude change in precipitation and also identify the areas where it is likely to occur.