BACKGROUNDA CORE OBJECTIVE OF THE PACE SCIENCE TEAM IS TO BETTER CHARACTERIZE AND ULTIMATELY CONSTRAIN ERRORS IN IOP MEASUREMENTS USED TO DEVELOP AND VALIDATE OCEAN COLOR REMOTE SENSING ALGORITHMS FOR THE FUTURE PACE MISSION. IN THIS CONTEXT TWO IOPS HAVE BEEN IDENTIFIED AS MOST RELEVANT FOR OCEAN COLOR APPLICATIONS THE ABSORPTION AND BACKSCATTERING COEFFICIENTS. FOR ABSORPTIONSPECIFICALLY THE LAST COMMUNITY ATTEMPT AT CLOSURE BETWEEN MULTIPLE SENSORS AND APPROACHES WAS PUBLISHED BY PEGAU 1995. AS MANY SIGNIFICANT ADVANCES HAVE BEEN MADE SINCE THAT STUDY A FOCUSED FIELD EFFORT IS REQUIRED TO INTERCOMPARE VARIOUS STATE OF THE ART APPROACHES FOR DERIVING ABSORPTION COEFFICIENTS AND TO ASSESS ASSOCIATED UNCERTAINTIES.OBJECTIVEMEASURE ABSORPTION COEFFICIENTS WITH THE HIGHEST QUALITY METHODS KNOWN AT THIS TIME AS CONCURRENTLY IN TIME AND SPACE AS POSSIBLE TO RIGOROUSLY ASSESS UNCERTAINTIES FOR VALIDATION AND ALGORITHM DEVELOPMENT FOR THE FUTURE PACE MISSION.