Numerical study on the influence of lake-land circulation on evaporation in Bosten Lake

Xinjiang is situated in the interior of the Eurasian continent. It is characterized by arid climatic conditions, presenting an uneven spatial and temporal distribution of water resources and a paucity of accessible water resources. Lakes constitute one of the primary means of water resource storage in Xinjiang. They play a pivotal and irreplaceable role in combating desertification within the arid region. Through complex multi-interface and multi-factor physical processes occurring within the atmospheric boundary layer, lakes modulate the regional exchange and circulation of water and heat materials. In this research endeavor, Bosten Lake was chosen as the focal point. The WRF-CLM model was employed to simulate the local circulation patterns over a span of 92 days from June to August in the summer of 2020. By meticulously analyzing the near-surface wind fields and water vapor distribution, and in conjunction with lake-removal experimental setups, the mechanism underlying the influence of local circulation on the evaporation of the lake surface was unearthed. The details unfold as follows: When the lake breeze holds sway, the water vapor that evaporates from the lake surface is ferried towards the land, propelled by the onshore air currents. Concurrently, under the sway of the updraft at the lake breeze front, it disperses into the upper atmosphere. Under the combined forces of the valley wind and background wind, the lake breeze circulation drives the water vapor downward, congregating it along the lakeshore to form discretely scattered water vapor accumulation zones. The specific humidity within these areas persists at an elevated level. The water vapor accumulation area of Bosten Lake is predominantly distributed on the western flank of the lake. Notably, the boundary layer height in these regions is lower than that of the neighboring land surfaces, and the underlying surface is largely blanketed by vegetation.