NNL14AA00C

IGF::OT::IGF THIS EFFORT INVOLVES OVERSIGHT AND PARTICIPATION IN MISSION PLANNING AND OPERATIONS, SCIENCE ALGORITHM AND SOFTWARE DEVELOPMENT AND MAINTENANCE, VALIDATION AND DATA PRODUCT GENERATION, DISTRIBUTION AND ARCHIVAL, SCIENCE COMMUNITY USER SUPPORT, COMMUNICATION AND PUBLIC ENGAGEMENT AND PUBLICATION OF RESULTS IN SCIENTIFIC JOURNALS AND TECHNICAL MEETINGS IN SUPPORT OF THE GRAVITY RECOVERY AND CLIMATE EXPERIMENT (GRACE) MISSION. THE GRACE MISSION PRODUCES A NEW MODEL OF THE EARTH'S GRAVITY FIELD ON APPROXIMATELY 30-DAY INTERVALS. THIS 30-DAY SAMPLE ALLOWS FOR THE DETERMINATION OF BOTH A HIGH-ACCURACY STATIC FIELD (OR MISSION AVERAGE MEAN FIELD) AND ITS TIME VARIATIONS AT MONTHLY INTERVALS. THE GRACE MISSION WILL CONTINUE TO DEFINE THE GRAVITY FIELDS BY FLYING TWO POLAR-ORBITING SATELLITES IN A LOOSELY CONTROLLED TANDEM FORMATION. VARIATIONS IN THE EARTH'S GRAVITY FIELD, RESULTING FROM VARIATIONS IN THE EARTH S MASS DISTRIBUTION, WILL CAUSE THE DISTANCE BETWEEN THE TWO SATELLITES TO VARY. THIS VARIATION WILL BE MEASURED WITH A PRECISION BETTER THAN 10 MICRONS BY A MICROWAVE LINK BETWEEN THE TWO SATELLITES. THE POSITION OF EACH SATELLITE IS DETERMINED BY USING GPS MEASUREMENTS COLLECTED ONBOARD EACH SATELLITE. ANALYSIS OF THIS DATA HAS RESULTED IN NUMEROUS ADVANCES IN EARTH SCIENCE RELATING TO OCEANOGRAPHY, LAND SURFACE HYDROLOGY, AND OBSERVATION OF POLAR ICE MASS CHANGE. THE MEASUREMENTS COLLECTED BY THE GPS RADIO OCCULTATION CO-EXPERIMENT HAVE BEEN RECOGNIZED AS AN IMPORTANT INPUT FOR NUMEROUS INTERNATIONAL WEATHER PREDICTION MODELS. IN ADDITION, THE 2013 NASA SENIOR REVIEW PROCESS ACKNOWLEDGED THE VALUE OF MASS FLUX OBSERVATIONS BEING OPERATIONALLY ASSIMILATED INTO HYDROLOGICAL MODELS TO SUPPORT ANALYSIS OF REGIONAL HAZARDS SUCH AS FLOODS AND DROUGHT. GRACE IS A PI-LED MISSION, AND AS SUCH THE PI S INSTITUTION, THE CONTRACTOR (UNIVERSITY OF TEXAS), SHALL BE RESPONSIBLE FOR MANAGEMENT OF ALL ELEMENTS OF THE MISSION INCLUDING COORDINATING THE MISSION CONTRIBUTIONS OF TEAM PARTNERS, JPL (PROJECT MANAGER AND MISSION OPERATIONS MANAGEMENT), UT, DLR, GERMAN RESEARCH CENTRE FOR GEOSCIENCES (GFZ), AND THE ACTIVITIES OF THE JOINT U.S./EUROPEAN GRACE SCIENCE TEAM.