THE UPPER ATMOSPHERE OF MARS INCLUDING THE UPPER MESOSPHERE AND THERMOSPHERE PROVIDE THE MAIN RESERVOIR FOR ATMOSPHERIC ESCAPE. GIVEN ITS DIRECT EXPOSURE TO SOLAR EXTREME ULTRAVIOLET (UV) RADIATION AND ITS STRONG COUPLING WITH THE LOWER ATMOSPHERE THE UPPER ATMOSPHERE IS SUBJECT TO STRONG VARIABILITY DRIVEN BOTH FROM ABOVE (SOLAR FORCING) AND FROM BELOW (VIA WAVES AND TIDES). THE AIM OF THIS PROPOSAL IS TO UNDERSTAND AND CHARACTERIZE THE MIDDLE AND UPPER ATMOSPHERE DYNAMICS USING THE UV AIRGLOW MEASUREMENTS FROM MARS. THIS WILL BE ACHIEVED BY ANALYZING TWO LARGE UV DAYGLOW DATASETS FOR MARS AND INTERPRET THE RESULTS USING MARS GENERAL CIRCULATION MODELS (GCM). WE WILL USE 10 YEARS OF DAYGLOW DATA OBSERVED BY SPICAM (SPECTROSCOPY FOR THE INVESTIGATION OF THE CHARACTERISTICS OF ATMOSPHERE OF MARS) ONBOARD MARS EXPRESS AND COMPREHENSIVE DAYGLOW DATA FROM IUVS (IMAGING ULTRAVIOLET SPECTROGRAPH) ONBOARD MAVEN MISSION. THIS WILL BE THE FIRST TIME THAT COMPLETE DATASETS FROM THE TWO MOST POWERFUL UV INSTRUMENTS WILL BE INTERPRETED USING TWO OF THE MOST COMPLETE GCMS. THE PROPOSED RESEARCH WILL GREATLY ENHANCE THE SCIENTIFIC RETURN FROM MARS DATA AS STATED IN MDAP SOLICITATION.