The Characteristic Behavior of Advection in the Planetary Boundary Layer as Observed by a Network of Ground-Based Thermodynamic and Kinematic Profilers

Advection is a key component of the temperature and moisture budgets in the planetary boundary layer (PBL), yet it is difficult to measure directly. Recent work by this team has demonstrated the feasibility and accuracy of measuring profiles of both temperature and moisture advection from the array of ground-based profiling sites at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) research facility. This is achieved by using the temperature and water vapor profiles retrieved from the network of infrared sounders at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in Oklahoma, including the Atmospheric Emitted Radiance Interferometers (AERI) and the Atmospheric Sounder Spectrometer by Infrared Spectral Technology (ASSIST). The thermodynamic profiles are united with wind profiles from the collocated Doppler lidars, and the advection can then be inferred from an approximation of the line integral around the polygon defined by the profiling sites at the vertices. Results from this method agree well with numerical weather prediction (NWP) calculations of advection. Observations of advection have already been used to enable new understanding about boundary layer processes, especially in quantifying latent and sensible heat budgets in PBLs undergoing morning and evening transitions.

Since advection is such a challenging parameter to observe, little is known about its basic behavior. These observations enable the development of a climatology of advective behavior in the PBL at the SGP site, including how it changes as a function of time and height and the advective influence of the low-level jet. This presentation will first feature a brief overview of how this method can be applied to the thermodynamic and kinematic profiles measured by AERI/ASSIST and Doppler lidar; subsequently, it will explore these key questions on the magnitude and evolution of PBL advection and how important parameters related to land surface/atmosphere interactions can be derived once such observations are available.