A drainage wind flow model.

Area of Science:

• Meteorology
• Atmospheric Science
• Environmental Engineering

Background:

• Drainage winds are crucial for understanding nocturnal atmospheric boundary layer dynamics.
• Accurate prediction of wind velocities is essential for air quality modeling and pollutant dispersion studies.

Purpose of the Study:

• To develop a novel method for predetermining drainage wind velocities.
• To provide a tool for analyzing nighttime air pollutant movement and flow patterns.

Main Methods:

• An incremental velocity model was developed, utilizing topographical data and surface roughness parameters.
• Velocity factors were calculated as a function of height and time since maximum surface temperature.
• Summation techniques were employed to determine time or space mean velocities.

Main Results:

• The model yields velocity factors that, when multiplied by a cooling factor, provide accurate wind velocities.
• The method allows for the computation of drainage flow patterns and pollutant trajectories.
• Predicted velocities are dependent on terrain characteristics and thermal cooling rates.

Conclusions:

• The incremental velocity model offers a reliable approach for predicting nighttime drainage winds.
• This method can be applied to assess air pollutant dispersion in localized areas.
• The model's flexibility allows for adaptation to various topographical and surface roughness conditions.