CONVECTION AND LARGE-SCALE FLOWSTHE OVER-ARCHING THEME OF THE CONVECTIVE PROCESSES IN THE TROPICS (CPEX) FIELD PROGRAM AS INDICATED IN THE ANNOUNCEMENT OF OPPORTUNITY IS TO MAKE THE MEASUREMENTS NEEDED TO IMPROVE THE REPRESENTATION OF TROPICAL DEEP CONVECTION IN LARGE-SCALE NUMERICAL MODELS. WE PROPOSE TO PARTICIPATE IN THIS PROGRAM. WE HAVE RECENTLY DEVELOPED A FRAMEWORK FOR UNDERSTANDING THE INTERACTIONS BETWEEN CONVECTION AND THE LARGE-SCALE FLOW. THIS FRAMEWORK POSTULATES THAT CONVECTIVE BEHAVIOR CAN BE SPLIT INTO A COMPONENT PREDICTABLE BY THE DYNAMICALLY BALANCED PART OF THE LARGE-SCALE FLOW AND AN INTRINSICALLY RANDOM CHAOTIC COMPONENT. ONLY THE STATISTICAL BEHAVIOR OF THE LATTER IS POTENTIALLY PREDICTABLE. FLOWS IN THE TROPICS ARE GENERALLY CONSIDERED TO BE LARGELY UNBALANCED BUT IN FACT BOTH THEORY AND OBSERVATIONS INDICATE THAT THE MAJORITY OF LARGE-SCALE TROPICAL WEATHER DISTURBANCES ARE DOMINATED BY BALANCED VORTICITY DYNAMICS. IN OUR FRAMEWORK TWO ASPECTS OF CONVECTIVE BEHAVIOR ARE CENTRAL TO THE INTERACTION WITH THE LARGE-SCALE FLOW. (1) THE AVERAGE VERTICAL MASS FLUX PROFILE OF A CONVECTIVE ENSEMBLE DRIVES THE EVOLUTION OF THE LARGE-SCALE VORTICITY. (2) THE MOIST ENTROPY BUDGET OF THE ENSEMBLE IN PARTICULAR THE TENDENCY FOR COLUMN MOIST ENTROPY TO INCREASE OR DECREASE IS AN EXCELLENT INDICATOR OF THE FUTURE BEHAVIOR OF THE ENSEMBLE. THE ENTROPY BUDGET IS CONTROLLED BY A COMBINATION OF SURFACE HEAT AND MOISTURE FLUXES CLOUD-RADIATION INTERACTIONS AND LATERAL ENTRAINMENT AND DETRAINMENT OF MOIST ENTROPY. ALL OF THE ABOVE QUANTITIES CAN BE MEASURED USING ARRAYS OF DROPSONDES. FURTHERMORE THE AVAILABILITY OF DOPPLER LIDAR AND K-BAND DOPPLER RADAR ON THE NASA DC-8 WILL SUBSTANTIALLY IMPROVE THE QUALITY OF THESE MEASUREMENTS AS LOWER TROPOSPHERIC FLOWS AROUND CONVECTION ARE TYPICALLY A COMPLEX MIXTURE OF TURBULENCE UPDRAFTS DOWNDRAFTS AND DOWNDRAFT OUTFLOWS WITH SIGNIFICANT VARIABILITY ON SCALES SMALLER THAN CAN BE MEASURED WITH DROPSONDES. THE ABOVE DATA WILL BE USED TO ADDRESS THE GOALS OF CPEX. THE MAIN SOURCES OF SUMMERTIME CONVECTIVE VARIABILITY (ASIDE FROM THE DIURNAL CYCLE) IN THE EASTERN CARIBBEAN ARE EASTERLY WAVES AND TROPICAL CYCLONES. BOTH ARE QUASI-BALANCED DISTURBANCES THAT CAN SERVE AS MODELS FOR THE BROAD SPECTRUM OF BALANCED PHENOMENA IN THE TROPICS. THUS A FOCUS ON OBSERVING CONVECTION IN THE DIFFERENT PHASES OF THE EASTERLY WAVE CYCLE IS LIKELY TO PROVIDE RESULTS THAT HAVE WIDE APPLICABILITY IN TROPICAL REGIONS. PERSONNEL: PI DAVID RAYMOND WOULD PROVIDE OVERALL GUIDANCE TO THE PROJECT INCLUDING PARTICIPATION IN FLIGHT PLANNING MISSION EXECUTION DATA ANALYSIS AND PUBLICATION OF RESULTS. HE HAS EXTENSIVE EXPERIENCE IN RESEARCH FLIGHT OPERATIONS AND GUIDED GRADUATE STUDENT ANA JURAI IN HER PARTICIPATION IN HS3. CO-PI ELJKA FUCHS HAS BEEN HEAVILY INVOLVED IN THE DEVELOPMENT OF OUR THEORETICAL FRAMEWORK FOR CONVECTION AND BALANCED FLOW. SHE WOULD PARTICIPATE IN FLIGHT PLANNING AND EXECUTION AND TAKE THE LEAD IN DATA ANALYSIS AND WORK WITH THE PI IN PUBLICATION OF RESULTS. CARLOS L PEZ DEVELOPED THE 3-D VARIATIONAL SCHEME THAT WE USE FOR ANALYZING DROPSONDE AND DOPPLER RADAR DATA AND WOULD BE RESPONSIBLE FOR EXTENDING THIS SOFTWARE TO INCORPORATE DOPPLER LIDAR AND K-BAND RADAR RESULTS. CARLOS HAS EXTENSIVE MISSION SCIENTIST EXPERIENCE ON THE NOAA P-3 AND THE NCAR/NSF GULFSTREAM V AND ASSISTED IN FLIGHT PLANNING IN THE FIRST YEAR OF HS3. WE HAVE TALENTED UNDERGRADUATE STUDENTS EAGER TO PARTICIPATE IN THIS PROJECT.