Effect of Urban Areas on Mixing-Layer Height

A Doppler wind lidar (DWL) has been making measurements of mean horizontal wind profiles and mixing layer heights in the suburban area of Indianapolis, IN as part of the Indianapolis Flux Experiment (INFLUX) for quantification of greenhouse gas emissions from the urban area. A second DWL was deployed climatologically upwind of the city for a three month period in Fall 2017 to study the urban influence on the boundary layer. Similarly two DWLs were set up within and outside the city of Boulder, CO in summer 2018. Here we investigate the effect of urban areas on mixing height including identification of atmospheric conditions that modify the effect of urban areas. Mixing layer heights were retrieved from DWLs using a recently developed composite fuzzy logic approach that combines information from various scan types (Plan Position Indicator (PPI), Range Height Indication (RHI), zenith and off-angle stares). The DWL-measured mixing heights were also compared with mixing heights from collocated backscatter lidars and radiosondes.