Climatology of Boundary Layer Depth over the US Southern Great Plains

English Abstract:

The boundary layer (BL) is an important link between the surface and free troposphere that heavily modulates the transport of energy and momentum between them. In a convective environment clouds often form on the top of the mixed layer providing a constraint on the radiative heating of the surface and the energy transport. The BL over land also exhibits considerable changes (in structure, depth etc.) on diurnal, seasonal and annual timescales. In this study we have used long-term (~20 years) data collected at the Atmospheric Radiation Measurement (ARM)’s Southern Great Plains (SGP) observational facility near Lamont, Oklahoma that has been operational since October, 1993. The Radar Wind Profiler (RWP) operating at 915 MHz frequency made observations of the raw Doppler spectrum and its moments continuously (>80% uptime) at a 60 m and 30 second resolution. These observations were used to deduce BL depth on hourly time-scales from which it’s diurnal, seasonal and annual cycles were deduced. The data collected by collocated instruments like the ceilometer, microwave radiometer, flux suite and met system were also used to characterize environmental conditions.

We will present the diurnal, seasonal and annual cycle of the RWP derived BL depth in the context of the environmental conditions as observed over the US Southern Great Plains.