FEEDBACKS ASSOCIATED WITH THE VARIATIONS OF DEEP CONVECTION AS SURFACE TEMPERATURES INCREASE HAVE LONG BEEN HYPOTHESIZED MECHANISMS FOR REGULATING CLIMATE SENSITIVITY. RECENTLY THE IDEA OF DEEP CONVECTION ACTING AS AN IRIS TO MODULATE THE RADIATION BUDGET AND IMPACT CLIMATE SENSITIVITY HAS BEEN REINVIGORATED ALBEIT WITH A DIFFERENT MECHANISM THAN THE ORIGINAL IRIS HYPOTHESIS. IT WAS ORIGINALLY HYPOTHESIZED THAT THE IRIS OCCURRED THROUGH CHANGES IN THE CLOUD MICROPHYSICAL PROCESSES WITH INCREASING TEMPERATURE. RECENT LITERATURE SUGGESTS INSTEAD THAT INCREASES IN PRECIPITATION WITH A LOSS OF DETRAINED ANVIL CLOUD AREA COULD OCCUR IF AGGREGATION OF CONVECTION IS TEMPERATURE DEPENDENT. IT HAS ALSO BEEN SUGGESTED THAT THIS TEMPERATURE DEPENDENCE OF AGGREGATION MAY BE A CONTRIBUTOR TO THE NARROWING OF THE LARGE-SCALE CONVERGENCE ZONES WITH A WARMER CLIMATE SHOWN IN BOTH MODEL SIMULATIONS AND IN OBSERVATIONS. HERE WE PLAN TO EXPLOIT THE SYNERGY OF THE TRMM VISIBLE AND INFRARED SCANNER (VIRS) TRMM MICROWAVE IMAGER (TMI) AND PRECIPITATION RADAR (PR) OBSERVATIONS TO FURTHER INVESTIGATE THE RELATIONSHIP BETWEEN PRECIPITATION AND ANVIL CLOUD AREA AS CONVECTION AGGREGATES AND THE RELATIONSHIP BETWEEN THE POPULATION OF CONVECTIVE SYSTEMS AND ITCZ WIDTH VARIATIONS. TO ADDRESS THESE GOALS THERE ARE THREE MAIN OBJECTIVES OF THE PROPOSED WORK: 1. DEVELOP PRECIPITATING CLOUD OBJECT DATABASE USING TRMM VIRS TMI AND PR 2. DETERMINE HOW THE POPULATION OF PRECIPITATING CLOUD OBJECTS VARIES AND HOW THEIR PRECIPITATION-ANVIL AREA CHANGES FUNCTION OF THE ENVIRONMENT 3. DETERMINE HOW THE PRECIPITATION-ANVIL AREA RELATIONSHIPS CHANGE AS A FUNCTION OF LARGE-SCALE ITCZ CHARACTERISTICS. WITH THIS ANALYSIS WE HOPE TO ANSWER A NUMBER OF QUESTIONS INCLUDING - HOW DOES SST AND WATER VAPOR CONTROL THE FREQUENCY OF MULTICORE AGGREGATED CONVECTION? - HOW DOES THE PRECIPITATION TO CLOUD AREA RATIO VARY WITH THE DYNAMIC AND THERMODYNAMIC ENVIRONMENT AND IS THE VARIATION IN PRECIPITATION OR CLOUD AREA THE PRIMARY DRIVER? - DO MULTICORE SYSTEMS PRODUCE MORE OR LESS ANVIL CLOUD PER PRECIPITATING CORE AREA THAN ISOLATED CONVECTIVE SYSTEMS? - DOES THE POPULATION OF ISOLATED VS. AGGREGATED MULTICORE SYSTEMS CHANGE AS A FUNCTION OF ITCZ WIDTH? - DOES THE RATIO OF PRECIPITATION TO ANVIL CLOUD AREA VARY WITH ITCZ WIDTH? THE PROPOSED RESEARCH ADDRESSES SOLICITED RESEARCH CATEGORY 2.2 UTILIZATION OF SATELLITE/GV DATA PRODUCTS FOR PROCESS STUDIES AND MODEL DEVELOPMENT. IT IS SPECIFICALLY TARGETED AT SOLICITED TOPICS OF IMPORTANCE INCLUDING STUDIES OF PRECIPITATION TO BETTER UNDERSTAND STORM STRUCTURES PRECIPITATION TRENDS AND EXTREMES WATER/ENERGY BUDGETS AND VARIABILITY LATENT HEATING FRESHWATER RESOURCES AND INTERACTIONS BETWEEN PRECIPITATION AND OTHER CLIMATE PARAMETERS AND ANALYSIS OF TRMM GPM AND OTHER SATELLITE-BASED PRECIPITATION INFORMATION FOR OBSERVATIONAL STUDIES OF CLIMATE AND WEATHER. IT ALSO ADDRESSES A NUMBER OF RESEARCH QUESTIONS HIGHLIGHTED IN THE 2017-2027 DECADAL SURVEY INCLUDING HOW IS THE WATER CYCLE CHANGING? AND HOW CAN WE REDUCE UNCERTAINTIES IN GLOBAL CLIMATE SENSITIVITY? .