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Inter-Calibration for the Passive Microwave Imager

Inter-Calibration for the Passive Microwave Imager. 20 th GSICS Executive Panel, Sochi, Russian Federation, 16-17 May 2019. Xiuqing (Scott) Hu, GRWG Chair Ralph Ferraro, MW Sub-Group Chair. Microwave Sub-Group.

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Inter-Calibration for the Passive Microwave Imager

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  1. Inter-Calibration for the Passive Microwave Imager 20th GSICS Executive Panel, Sochi, Russian Federation, 16-17 May 2019 Xiuqing (Scott) Hu, GRWG Chair Ralph Ferraro, MW Sub-Group Chair

  2. Microwave Sub-Group • MWSG has grown and is still expanding. Continue to engage with other communities.  Focus on methods to characterize MW sensors. Developing best practice, for example MW SNO. Matrix of deliverable products.

  3. MW Sub-Group Focus Topics for 2018-2019 •  Defining CLEAR PATH for GSICS MW products, algorithms, tools, deliverables • Methodologies (Jun Park, Rachel Kroodsma) • SNO, Double difference, etc. • Reference Standards (Manik Bali, Isaac Moradi, Derek Houtz) • A particular sensor? Likely to be wavelength dependent (e.g., window, O2, H20); A RTM? • LUT/Correction Tables (KarstenFennig, Cheng-Zhi Zou, Viju John) • Near real-time and climate; they will be different • Tying together other groups/opportunities • GPM X-Cal (Wes Berg, Rachel Kroodsma) • CEOS MW subgroup (Cheng-Zhi, Xiaolong Dong, QifengLu, Tim Hewison) • Expanding active participation (Manik Bali, Ralph Ferraro) • CGMS - SCOPE-CM (KarstenFennig);IPWG (Ralph Ferraro) • GRUAN (Tony Reale, Cheng-Zhi Zou) • FIDUCEO (Martin Burgdorf, Bill Bell, Fabien Carminati) • GAIA-CLIM(Heather Lawrence/Steve English) • Address special requests/actions from CGMS • WIGOS2040 • Gap Mitigation • Continued participation by subgroup at meetings of relevance: • GSICS; CEOS;CALCON, Microrad, AMS Sat. Met, EUMESAT Satellite, etc.

  4. MW Session in 2019 Annual meeting

  5. Importance of a healthy microwave imager constellationAdapted from CGMS-46 paper on importance of GCOM-W1 follow-onPresented to CGMS-46 Plenary session, agenda item O

  6. GSICS Deliverable: Intercalibration Look Up Table (LUT) Courtesy of Rachael Kroodsmaetal. • Objective of the LUT • Identify a calibration standard and intercalibrate sensor brightness temperatures to that standard to create a consistent calibrated dataset • How it was created • The XCAL team identified the GPM GMI as the calibration standard • Used a variety of intercalibration methods to adjust the brightness temperatures of the GPM constellation radiometers to the GMI calibration • How to use it • Fortran and IDL read routines are provided References: Berg, W.; Kroodsma, R.; Kummerow, C.D.; McKague, D.S. Fundamental Climate Data Records of Microwave Brightness Temperatures. Remote Sens. 2018, 10, 1306. Berg, W., and Coauthors, 2016: Intercalibration of the GPM microwave radiometer constellation. J. Atmos. Oceanic Technol., 33, 2639–2654, doi:10.1175/JTECH -D-16-0100.1.

  7. PMM XCAL Team • The XCAL team is a working group within the Precipitation Measurement Missions (i.e. TRMM/GPM) science team responsible for the Level 1C intercalibrated brightness temperature files used as input to the operational precipitation retrieval algorithm for available constellation microwave radiometers. • Priorities: Focus on microwave sensors/channels used for precipitation retrievals. • Conical window channel imagers (10 – 90 GHz) • Cross-track water vapor sounders (150 – 183 GHz) • Temperature sounding instruments/channels not used Courtesy of Rachael Kroodsmaetal.

  8. Available Sensor Data • GPM GMI used as the calibration standard for the constellation • 13 imagers and 10 sounders intercalibrated to GMI Courtesy of Rachael Kroodsmaetal. GMI calibration references Draper, D. W., D. A. Newell, F. J. Wentz, S. Krimchansky, and G. Skofronick-Jackson, 2015: The Global Precipitation Measurement (GPM) Microwave Imager (GMI): Instrument overview and early on-orbit performance. IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens., 8, 3452–3462, doi:10.1109/JSTARS.2015.2403303. Wentz, F. J. and D. Draper, 2016: On-orbit absolute calibration of the Global Precipitation Mission Microwave Imager, J. Atmos. Oceanic Technol., 33, 1393–1412, doi:10.1175/JTECH-D-15-0212.1.

  9. Intercalibration Table Development • Cold (ocean) and warm (dense vegetation) scenes • Double difference method using a variety of techniques from different groups • Linear interpolation between the two tie points Courtesy of Rachael Kroodsmaetal.

  10. Intercalibration Table Values (Imagers) Courtesy of Rachael Kroodsmaetal.

  11. GPM X-Cal LUT’s as MW Deliverable • Microwave Inter-Calibration LUT’s have been submitted to the Subgroup to be assigned as GSICS Deliverables • These LUT’s have been created by inter-calibrating SSMI series of Instruments and GPM-X series of instruments • It is envisaged that that the LUT’s Microwave calibration community would enhance our understanding of the performance of these series of instruments. • It is also envisaged that analysis using the LUT’s would help us in identifying re-calibration pathways for MW instruments across a range of frequencies

  12. MW-sub group Actions(1/2)

  13. MW-sub group Actions(2/2)

  14. MW sub-group Summary (1/2) • 1. The calibration of newest MW sensors (NOAA-20, MetOp-C, AMSR-2, MWRI & MWRS) appear to be the best to date - newly launched sensors, agencies adopting GSICS methods. • 2. Stability of orbits in newer satellites appear to be paving the way for future references, esp. temp. sounding channels (Cheng-Zhi) • 3. Bringing closure on RTM differences may shed light on their use in DD techniques, although still needs to be some uniformity on how input data are used (i.e., we still seem to have not quite conquered filtering for clouds and other contaminants - could be a future MW group activity?) • 4. The NWP community is providing greater insight on sensor calibrations (Qifeng, Fabien, Alan, etc.), the OMB with the clear sky radiance fitting well, confirm another possible reference to evaluate and characterize the instruments.

  15. MW-sub group summary (2/2) • 5. GSICS MW deliverable - X-Cal MWI calibrations. Closure is coming soon, still need to iron out content provided and whether their methods could be duplicated by other agencies, and whether actual code could be shared (a CGMS matter?) • 6. Discussed MWI constellation gap and what its impacts are (Mitch, Alan, Fabien). There are EDR's that are unique to MWI, although MWS could fill in some gaps, esp. in weather applications. There are suggestions to dive deeper in particular areas such as snow and ice • (Mitch, a new CGMS group?). It was also noted that impact studies could demonstrate more than impact at 500 mb anomaly scores - what about particular devastating storms were MWI observations were critical in storm intensity and track? • 7. GSICS MW could provide a short summary paper on impact of MWI gap and possible solutions • 8. A Strawman draft of a plan to develop inter-calibration products for microwave imagers is outlined. This is initiating the outline of the GSICS MW response to WIGOS2040 to be reported on at CGMS-47

  16. Thank you

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