Climatology of Boundary Layer Depth at the ARM SGP Central Facility

Description

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 exhibits considerable changes (in structure, depth etc.) on diurnal, seasonal and annual timescales. Hence, it is necessary for the Global Climate Models (GCM) to accurately portray the BL and its variations in simulations aimed at predicting the future climate. In this study, we have used long-term (~20 years) data collected at the Atmospheric Radiation Measurement (ARM)’s Southern Great Plains (SGP) site that has been operational since October 1993 to characterize the BL depth in the context of other environmental variables. The Radar Wind Profiler (RWP) was continuously operational (>80% uptime) since 1993 and recorded the full Doppler spectrum and its moments in two pulse length settings. The RWP moments data collected during Short Pulse (SP) mode were used to retrieve hourly estimates of BL depth, from which its diurnal, seasonal and annual cycles will be calculated. Additionally, observations made by collocated instruments like radiosondes, ceilometer, microwave radiometer, flux suite and met system will be used to put the BL depth estimates in the context of environmental conditions.