A method for estimating planetary boundary-layer heights and its application over the ARM Southern Great Plains site
Poster PDF
Authors
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Dev Niyogi — Purdue University
Category
Atmospheric State & Surface
Description
A new objective method to determine the height of the planetary boundary layer (PBL) was developed using afternoon and evening radio soundings from the ARM Southern Great Plains (SGP) site. The SGP site was well suited for this task as heights could be compared with those measured by lidar, also at the site. Heights were computed using the statistical variance and kurtosis of dewpoint and virtual potential temperature differences measured from radio soundings in the early and late afternoon. Values compared favorably with the ARM lidar measurements, gridded model data from the North American Reanalysis, and previous studies measuring PBL height in the region. Boundary-layer heights were compared with measured heat fluxes and soil moisture to measure the degree of coupling between the surface and the free atmosphere. Heights were also compared with aerosol optical depth and cloud cover to measure the coupling between the boundary layer and convection. A climatology of mean afternoon PBL heights from 2002 to 2011 was prepared over the site and compared with a concurrent climatology of aerosols and cloud cover to measure the possible impacts of land-use change or aerosol loading on the PBL depth and surface energy exchange.
