AS DROUGHTS HAVE BECOME MORE FREQUENT OVER SOUTH AMERICA SINCE THE BEGINNING OF THIS CENTURY A BETTER UNDERSTANDING OF THE PROCESSES CONTROLLING THE SOUTH AMERICAN MONSOON SYSTEM (SAMS) THAT MAY RESULT IN EXTENDED PREDICTABILITY OF ITS INTENSITY ARE CALLED FOR AND ARE OF FUNDAMENTAL IMPORTANCE TO FOOD AND WATER SECURITY IN THE REGION. SINCE THE BEGINNING OF THE 21ST CENTURY ALONE THE AMAZON BASIN HAS HAD THREE MAJOR DROUGHT EVENTS WHICH IS CONSIDERABLY GREATER FREQUENCY THAN IN THE PREVIOUS TWO DECADES. THIS PROJECT WILL EXAMINE THE INTERANNUAL VARIABILITY OF THE ONSET DATE INTENSITY AND DURATION OF THE SAMS WITH RESPECT TO VARIOUS CLIMATE PATTERNS AS WELL AS A NEWLY DEVELOPED HIGH-RESOLUTION DATASET OF ITCZ VARIABILITY OVER THE ATLANTIC AND PACIFIC. MONSOON-RELATED INDICES WILL BE USED TO QUANTIFY VARIABILITY IN THE SAMS. THESE INDICES WILL BE ANALYZED AND CORRELATED TO THE MAJOR CLIMATE MODES LOCAL AS WELL AS GLOBAL. THE EL NINO SOUTHERN OSCILLATION (ENSO) IS THE MOST IMPORTANT GLOBAL CLIMATE MODE AND EXPLAINS MOST OF THE INTERANNUAL VARIABILITY IN RAINFALL IN THE SAMS AREA HOWEVER THE EFFECT OF ENSO ON ONSET DATE IS CONTROVERSIAL. OTHER CLIMATE PATTERNS SUCH AS THE SOUTHERN ANNULAR MODE (SAM) THE PACIFIC SOUTH AMERICAN (PSA) PATTERN WILL BE EXAMINED AS WELL AS THE LOCAL SIGNATURE OF THE AMAZONIAN VEGETATION OBTAINED BY THE NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI). THE NEWLY DEVELOPED DATASET OF HIGH-RESOLUTION ITCZ VARIABILITY BASED ON THE IR CHANNEL OF THE GRIDSATDATA FROM 1980 WILL BE USED TO EXAMINE INTRASEASONAL AS WELL AS INTERANNUAL RELATION BETWEEN SAMS AND ITCZ VARIABILITY. THE HYPOTHESIS IS THAT ATLANTIC SEA SURFACE TEMPERATURE VARIABILITY MAY HAVE A PREDICTIVE SIGNATURE ON INTERANNUAL TO DECADAL VARIABILITY OF THE INTENSITY OF SAMS. THIS SIGNATURE WOULD BE MOST READILY IMPARTED TO A PERTURBATION OF THE ATLANTIC ITCZ AS WELL AS PERTURBATION OF THE WALKER CIRCULATION CONNECTING ATLANTIC AND PACIFIC VARIABILITY IN THE TROPICS. THE PROJECT WILL FOCUS ON THE TIME PERIOD GOING BACK TO 1980 AND USE MERRA-2 REANALYSIS AS WELL AS GRIDSAT DATA. FOR MORE DETAILED EXAMINATION OF INTRASESAONAL VARIABILITY IN MORE RECENT YEARS THE PROJECT WILL USE TRMM RADAR DATA FOR PRECIPITATION MODIS NDVI DATA FOR VEGETATION VARIABILITY AND CLOUDSAT DATA FOR VERTICAL STRUCTURE OF THE CONVECTION.