Estimating Boundary Layer Tops with ARM Profiler Radars

The Atmospheric Radiation Measurement (ARM) program operates six 915-MHz and two 1290-MHz radar wind profilers at multiple sites worldwide. These UHF profilers can be configured (optimized) to facilitate studies relevant to both planetary boundary layer and precipitation microphysics. We describe new boundary layer algorithms based on the UHF profiler observations, and show their implementation for the ARM Climate Research Facility at the US Southern Great Plains in Oklahoma.

For this study, several days of precipitation-free conditions during July 2012 were selected. Doppler spectra from vertical beams at 417 ns pulse width, corresponding to profiles at about 62-meters vertical resolution and near 1.5-minutes time resolution are analyzed and input into the new retrieval algorithms to estimate the boundary layer top and its associated uncertainty.

For validation, the UHF estimates are compared with boundary layer tops obtained from radiosonde observations launched at the UHF profiler site every 6 hours (for each ascent, a radiosonde reading is recorded every 2-seconds and approximately 10 m vertical resolution). The radar-radiosonde comparisons are encouraging, and data-stream production is underway at the ARM Data Archive, as a new open-access Evaluation Value Added Product.