Bjorn Lambrigtsen Jet Propulsion Laboratory - California Institute of Technology Jet Propulsion Laboratory California Institute of Technology Pasadena, California This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration. Copyright 2008 California Institute of Technology. Government sponsorship acknowledged A “Geostationary AMSU” Hurricanes & severe storms 55-GHz warm core anomaly (continuously, in real time)  Surface pressure anomaly = Intensity Equivalent radar reflectivity (continuous coverage of entire life cycle)  Intensification/weakening, microphysics, convective structure Complete diurnal-cycle observations (< 15-minute time resolution)  Model improvements Real-time atmospheric stability indices (including under full cloud cover)  Severe storm warnings, tornado precursor detection AMV-inferred wind vectors (regardless of cloud cover)  Improved forecasts Synergies Complement GEO IR sounders (cloud clearing) Complement LEO sounders (swath-gap & temporal-gap filling) Complement GEO imagers (resolution enhancement of MW) Global Precipitation Mission (provide spatio-temporal continuity) Key component of GPM “super-constellation” Technology Proof-of-concept prototype- demonstrated in 2005 The GeoSTAR prototype National Aeronautics and Space Administration Antenna size is determined by distance and “spatial resolution” AMSU antenna is 6” in dia. and gives 40-km resolution from 705 km GEO orbit is ~37000 km ≈ 50 x 705 km AMSU-antenna must then be 50 x 6” to give 40-km res. from GEO This is 25 feet (8 meters)! Can’t be done! To get 50-km res. we need 20 feet. Still can’t be done Solution: Synthesize large antenna  GeoSTAR Low-earth-orbiting MW sounder (AMSU) Key element: The antenna Principle of aperture synthesis Science Dissecting hurricanes: 3D internal structure Height resolved “Radar reflectivity”  Use radar algorithms to derive Precipitation rate Ice water path Convective intensity Vertical structure Vertical slicing through hurricane Emily - July 17, 2005 EDOP HAMSR Nadir along-track view 2 km Scan swath view MW sounder Is equivalent to radar! Correlation between MW-sounder  Tb and radar reflectivity exceeds 90% at all levels except near surface Inferred from HAMSR 3 km 4 km 5 km 6 km 7 km 8 km 9 km 10 km 11 km 12 km 13 km 14 km 15 km Data products It works! Outdoor scene (far field) Indoor scene (near field) Calibration “Near Field range”, JPL GeoSTAR ”Earth” target Temperature controlled pads Computed from model Measured with GeoSTAR |Obs - Calc| < 2 K (Will be improved as system processing is optimized) Calibration facility at JPL: Earth-like disc viewed against cold-sky background mimicking Earth-view from GEO Develop Math model Assimilate Compare Obser- vations Initialize Adjust Forecast Models and observations Weather & climate models are deficient Cloud formation, convection & precipitation is not completely understood; “microphysics” is deficient Diurnal-cycle variations are not well modeled; storm life cycles are not well modeled Observations used to “feed” models are incomplete Most satellite sensors do not penetrate clouds nor observe the internal “microphysics” of clouds & storms Most satellites provide only brief snapshots twice a day, when the satellite passes overhead Therefore, we need… Continuous observations of the entire process: diurnal cycle, storm cycle, Observations under all weather conditions  GeoSTAR! Improve Applications Numerical weather prediction (regional/global NWP) —Assimilation of radiances; 4DVAR applications Hurricane now-casting (15-minute refresh cycle) —Intensity assessment, detect rapid intensification/weakening —Observation of internal dynamics, kinematics & microphysics Severe storm development (cloudy observations) —Atmospheric stability (CAPE, LI, etc.) in cloudy regions —Detect/assess tornado precursor conditions Weather hazard assessment (continuous observations) —Life cycle storm observations; total rainfall —Predict/observe flood conditions Climate studies (stable sensor with “legacy continuity”) —Continuous time series; diurnal cycle fully resolved —Basin-scale intra-seasonal to interannual analyses —Cross-calibration of LEO climate sensors & data series Temperature sounding channels Water vapor sounding channels Physical basis of microwave sounding Absorption spectrum Weighting functions Simulated brightness temperature images (tropospheric temperature sounding channels) Ready to build! Many accommodation options Currrent estimate mass = 230 kg power = 340 W BW = 1 Mbps Fly GeoSTAR on GOES-R/S/T?