THE MAIN GOALS OF THIS PROPOSAL ARE: 1) TO DEVELOP A CATALOG OF ATMOSPHERIC RIVERS (ARS) AT THE GLOBAL SCALE FOR THE PERIOD OF 1979 2017; AND 2) TO CHARACTERIZE THE RAINFALL ASSOCIATED WITH THESE EVENTS. ARS ARE FILAMENTARY REGIONS OF ENHANCED MOISTURE TRANSPORTIN THE LOWER TROPOSPHERE AND OCCUR IN THE PRE-COLD FRONTAL REGION (WITHIN THE WARM SECTOR) OF EXTRA-TROPICAL CYCLONES. ARS PLAY AMAJOR ROLE IN GLOBAL WATER CYCLE WITH ABOUT 90% OF THE POLEWARD ATMOSPHERIC WATER VAPOR TRANSPORT OCCURRING WITHIN THEM. THEY ARERESPONSIBLE FOR HEAVY RAINFALL AND FLOODING OVER LARGE AREAS OF THE MID-LATITUDE REGIONS. THIS PROPOSAL IS MOTIVATED BY THE FOLLOWINGMAIN RESEARCH QUESTIONS: WHAT IS THE SEASONAL AND INTER-ANNUAL VARIABILITY OF AR ACTIVITY OVER DIFFERENT REGIONS OF THE GLOBE? WHAT ARETHE RAINFALL PATTERNS WITHIN ARS AND HOW DO THEY CHANGE FROM OCEAN TO LAND?THE RESEARCH WILL BE IMPLEMENTED IN TWO PHASES OVER A THREE-YEAR TIME PERIOD. IN PHASE I I WILL ASSEMBLE AND ORGANIZE DATASETSNECESSARY FOR THE PROJECT AND DEVELOP STORM CATALOGS OF ARS AT THE GLOBAL SCALE. DURING PHASE II I WILL USE THE STORM CATALOGSDEVELOPED IN PHASE I TO EXAMINE THE RELATIONSHIPS BETWEEN ARS AND RAINFALL AND CHARACTERIZE THE RAINFALL DISTRIBUTION IN THESE SYSTEMS.THE GOALS OF THE PROPOSED RESEARCH ALIGN DIRECTLY WITH THOSE OF THE NASA S EARTH AND SPACE SCIENCE FELLOWSHIP (NESSF) PROGRAM PARTICULARLY WITH THE NASA S MISSION TO STUDY EARTH FROM SPACE TO ADVANCE SCIENTIFIC UNDERSTANDING AND MEET SOCIETAL NEEDS. I WILLUSE RAINFALL ESTIMATES FROM A NUMBER OF NASA PRODUCTS INCLUDING THOSE FROM THE UPCOMING GLOBAL PRECIPITATION MEASURING (GPM)MISSION TO EXAMINE THE RELATIONSHIP BETWEEN ARS AND RAINFALL.THE PROPOSED RESEARCH FITS WITHIN TWO MAIN SCIENCE FOCUS AREAS OF THE NASA S EARTH SCIENCE DIVISION - WATER AND ENERGY CYCLE AND WEATHER.