MOUNTAIN WAVES (MWS) ARE CREATED FROM WIND FLOW OVER OROGRAPHY. BECAUSE THEY HAVE NEAR-ZERO PHASE SPEEDS AND BREAK/ATTENUATE BELOW THE TURBOPAUSE AT Z~107 KM THEY DO NOT PROPAGATE INTO THE THERMOSPHERE. YET THE LARGEST QUIET-TIME ATMOSPHERIC GRAVITY WAVE (GW) WINTERTIME HOTSPOT OBSERVED BY GOCE AT Z=250-300 KM AND BY CHAMP AT Z=280-450 KM OCCURS OVER THE SOUTHERN ANDES. THE SOURCE OF THESE HOTSPOT GWS IS CURRENTLY UNKNOWN. HOWEVER RECENT MODELING STUDIES OF THE SOUTHERN ANDES AND MCMURDO STATION DURING THE WINTER FIND THAT MW BREAKING/ATTENUATION CREATES LOCAL BODY FORCES (I.E. HORIZONTAL ACCELERATIONS OF THE FLUID) THAT EXCITE SPECTRA OF LARGER-SCALE SECONDARY GWS SOME OF WHICH PROPAGATE INTO THE THERMOSPHERE. ALSO A RECENT GOCE CASE STUDY ON 5 JULY 2010 FOUND THAT BOTH OF THE ANALYZED GWS OVER THE SOUTHERN ANDES AT Z~280 KM HAD HORIZONTAL INTRINSIC PHASE SPEEDS LARGER THAN THE SOUND SPEED BELOW THE TURBOPAUSE; THEREFORE THESE GWS MUST HAVE BEEN CREATED IN THE THERMOSPHERE. FINALLY THEORY AS WELL AS A RECENT MODEL STUDY SHOW THAT IT IS PROBABLE THAT THE DISSIPATION OF THESE SECONDARY GWS IN THE THERMOSPHERE CREATES BODY FORCES THAT EXCITE SPECTRA OF TERTIARY GWS SOME OF WHICH HAVE INTRINSIC HORIZONTAL PHASE SPEEDS LARGER THAN THE SOUND SPEED BELOW THE TURBOPAUSE. THE KEY SCIENCE QUESTION WE INVESTIGATE IN THIS RESEARCH PROPOSAL IS: ARE THE QUIET-TIME WINTER CHAMP HOTSPOT GWS OVER THE SOUTHERN ANDES SECONDARY AND/OR TERTIARY GWS FROM OROGRAPHIC FORCING? IN THE PROCESS OF INVESTIGATING THIS PROCESS WE WILL ALSO OBTAIN AN IMPROVED FORMULA FOR THE MOLECULAR VISCOSITY IN THE MID/UPPER THERMOSPHERE. THE METHODS/TECHNIQUES WE USE ARE: 1) EXTRACT QUIET-TIME WINTERTIME GWS OVER THE SOUTHERN ANDES AND OTHER MOUNTAINOUS REGIONS FROM CHAMP DATA. DETERMINE THEIR HORIZONTAL WAVELENGTHS INTRINSIC PERIODS AND PROPAGATION DIRECTIONS USING A PREVIOUSLY-DEVELOPED METHOD THAT UTILIZES THE GW DISSIPATIVE DISPERSION AND POLARIZATION RELATIONS. DETERMINE THE GW PARAMETERS AS FUNCTIONS OF ALTITUDE LATITUDE LONGITUDE AND TIME. REVERSE RAY-TRACE THE GWS TO POSSIBLE SOURCES. 2) QUANTIFY THE MWS DURING SELECT EVENTS USING AIRS AND MERRA-2 DATA. CALCULATE THE EXCITATION PROPAGATION AND DISSIPATION OF SECONDARY AND TERTIARY GWS USING THE PI'S BODY FORCE AND RAY TRACE MODELS. FORWARD RAY TRACE THE SECONDARY AND TERTIARY GWS TO CHAMP ALTITUDES. COMPARE THE CHAMP AND MODELED GWS. IF THERE ARE DIFFERENCES ADJUST THE MODELS OVER A REASONABLE RANGE TO SEE IF AGREEMENT IS POSSIBLE. ESTIMATE THE NEUTRAL WIND CHANGES CREATED WHERE THE SECONDARY AND TERTIARY GWS DISSIPATE IN THE THERMOSPHERE. 3) DETERMINE THE ALTITUDINAL PROFILE OF THE MOLECULAR VISCOSITY FROM Z=280-450 KM AS A FUNCTION OF THE BACKGROUND DENSITY USING THE ANALYZED CHAMP GWS. THIS PROPOSED WORK SATISFIES THE CRITERIA OF THIS SOLICITATION BECAUSE IT INCLUDES A) NUMERICAL SIMULATION AND MODELING AND B) THE ANALYSIS OF NASA-SPACECRAFT DATA. CHAMP AND AQUA ARE LISTED AS HISTORICAL AND CURRENT NASA MISSIONS AT HTTPS://WWW.NASA.GOV/ MISSIONS. THE DATA ANALYSIS AND MODELING PROPOSED HERE ADDRESS THE HELIOPHYSICS DECADAL SURVEY GOAL: "DETERMINE THE DYNAMICS AND COUPLING OF EARTH S MAGNETOSPHERE IONOSPHERE AND ATMOSPHERE AND THEIR RESPONSE TO SOLAR AND TERRESTRIAL INPUTS" BECAUSE WE SEEK TO DETERMINE HOW MWS (WHICH ARE TERRESTRIAL INPUTS OF ENERGY AND MOMENTUM) VERTICALLY-COUPLE WITH GWS IN THE MID/UPPER THERMOSPHERE. A KEY FACILITATOR OF THIS COUPLING PROCESS IN THE THERMOSPHERE IS MOLECULAR VISCOSITY WHICH WE SEEK TO FURTHER QUANTIFY. THE PROPOSAL TEAM COVERS THE NECESSARY EXPERTISE THAT THE TECHNIQUES REQUIRE: PI VADAS HAS THE IN-HOUSE BODY FORCE AND RAY TRACE MODELS AND EXPERTISE ANALYZING GWS CO-I YUE HAS EXPERTISE EXTRACTING WAVES FROM SATELLITE DATA AND CO-I BOSSERT HAS EXPERTISE QUANTIFYING MWS IN AIRS DATA. THE MODELING STUDIES WILL ALSO UTILIZE PUBLICLY-AVAILABLE MERRA-2 HWM AND MSIS DATA.