WE WILL INVESTIGATE THE STRUCTURE AND PROCESSES OPERATING IN THE MARS PLANETARY BOUNDARY LAYER (PBL) USING EXISTING ORBITAL DATAM SUPPLEMENTED BY SURFACE OBSERVATIONS AND WITH INTERPRETATION AIDED BY MODELS. OUR PRIMARY DATA SETS FOR ANALYSIS ARE THOSE PROVIDED BY THE MARS RECONNAISSANCE ORBITER MARS CLIMATE SOUNDER (MCS) AND MARS EXPRESS RADIO SCIENCE (RS). THESE ARE HEAVILY SUPPLEMENTED BY PREVIOUSLY ANALYZED DATA FROM THE MARS GLOBAL SURVEYOR THERMAL EMISSION SPECTROMETER (TES). WE FURTHER EMPLOY THE NASA AMES MARS GENERAL CIRCULATION MODEL (MGCM) TWO MESOSCALE MODELS (MRAMS; RAFKIN ET AL. 2001) AND OSU-MM5 [TYLER ET AL. 2002] AND TWO LARGE EDDY SIMULATION (LES) MODELS (MRAMS; [MICHAELS AND RAFKIN 2004] AND OSU [TYLERET AL. 2008]).