The LES simulation explicitly reproduces the turbulence and atmospheric circulations of the Amazon river winds. The LES simulations examined the effects of river winds on air pollution dispersion. It is also an important component of theRuisdael observatory. This model is developed at the Meteorology and Air Quality Group of Wageningen University & Research. To support the interpretation of these observations, this study includes a modeling component to couple field observations of river winds and chemistry with fine-scale modeling analyses using a large eddy simulation (LES). The impacts of atmospheric recirculation tied to the river winds on the air quality of nearby human populations were considered. Sensor-equipped UAVs were used to collect in situ vertical information of meteorological and chemical data in the lower atmosphere during the daytime over the Rio Negro river in the central Amazon. They have a potential advance in atmospheric studies due to extreme maneuverability in collecting data at high horizontal and vertical resolutions. Therefore medium-sized unmanned aerial vehicles (UAV-see photo) were used. Traditional meteorology and pollution measurement platforms are unable to measure how wind, temperature, moisture and air pollutants changes with height above the river. A key question then arise: How to obtain accurate observational evidence of these river wind circulations? Because these driving forces combine with larger and smaller atmospheric flows of trade winds and local topography, the combined river winds remain elusive and difficult to understand, measure and simulate.

At night, the land cools more rapidly, and the air circulation reverses because the river is warmer. The result is a closed local air circulation cell in the vertical plane (Figure 1). Subsequently, the air subsides over the river. The air masses in turn drive onshore air movement from the river toward the land. During the daytime, warmer temperatures over the land lead to lighter air masses that are lifted. River winds are induced by the daily thermal contrast between the land and the river. Conceptual representation of thermally driven recirculatory flow of river winds and potential impacts on the dispersion of urban pollution over the river-city landscape and river-forest landscape.

Air dispersion modeling software