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Masahiro Kazumori Japan Meteorological Agency

Recent activities on utilization of microwave imager data in the JMA NWP system - Preparation for AMSR2 data assimilation -. Masahiro Kazumori Japan Meteorological Agency. AMSR-E Joint Science Team Meeting, Portland, OR, U.S.A. 11 & 12 September 2012. Introduction.

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Masahiro Kazumori Japan Meteorological Agency

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  1. Recent activities on utilization of microwave imager data in the JMA NWP system- Preparation for AMSR2 data assimilation - Masahiro Kazumori Japan Meteorological Agency AMSR-E Joint Science Team Meeting, Portland, OR, U.S.A. 11 & 12 September 2012

  2. Introduction • Microwave imager data has been assimilating in JMA Global Data Assimilation (DA) system and Meso scale DA system. • The radiance assimilation provides atmospheric moisture information for initial state of NWP models. • The assimilated Microwave imager data • Clear Sky radiance data for Global DA system • Radiance and Retrieved Rain Rate for Meso scale DA system • In Use • TMI/TRMM • AMSR-E/Aqua(by Oct. 6, 2011) • SSMIS/DMSP F-16, F-17, F-18 • In Preparation • Windsat/Coriolis • AMSR2/GCOM-W1 • V-pol. channels (19, 23, 37 and 89) are assimilated in JMA NWP system. (since Dec. 6, 2011)

  3. Impact of microwave imager data in JMA NWP • MW imager data is one of the essential data to produce realistic moisture fields as initial conditions of NWP. • The initial fields are updated (four times per day for Global DA, eight times for Meso scale DA) to capture change of weather conditions. • Use of multiple MW imager data is necessary for the frequent update of the initial field. New MW imager data should be used. Short-range precipitation forecast TRMM observed rain Without Microwave Imager data Operational JAXA

  4. Recent updates of MW radiance assimilation in JMA • Oct. 6, 2011 Stop of AMSR-E observation • Dec. 1, 2011 Start of TMI ver. 7 Tb data use • Dec. 6, 2011 Start of DMSP F-18 SSMIS Tb use Time sequence of O-B statistics Start of TMI ver. 7 (Dec. 1) [K] Stop of AMSR-Eobservation (Oct. 6) Introduction of F-18 SSMIS (Dec. 6 )

  5. Used MW radiance data in Global DA Time sequence of Data Counts Available data number of DMSP F-17 SSMIS is decreasing since June 2011. [Counts] Decrease of DMSP F-17 SSMIS data

  6. In the data assimilation, satellite data are thinned spatially and temporally (e.g. , 200km and hourly). Satellite data in separate orbit are preferred because they increase the data coverage in six-hour analysis time window. Equator crossing time F-16 The orbit of SSMIS (F-16 and F-17) are becoming very close. F-17 12UTC Jun. 10, 2011 Both F-16 and F-17 data can be used because they are in the different thinning box. F-18 12UTC Sep. 4, 2012 One satellite (F-16) data can be used because they are in the same thinning box. Aqua

  7. Cal/Val collaboration with JMA and JAXA • JAXA successfully launched GCOM-W1. And AMSR2 is working in very good condition. • For early use of satellite data in operational NWP, Space agency and NWP center are collaborating in Cal/Val activities (e.g., AMSU-A/Metop-A, ECMWF and EUMETSAT, SSMIS/DMSP F-16, UK Met Office, NESDIS and NRL, ATMS/Suomi-NPP,NCEP, NESDIS, and NASA ) • Comparison of observed Tb and NWP model’s calculated Tb reveals Tb calibration issues. • For early use of AMSR2 data in JMA NWP, JMA and JAXA started Cal/Val collaboration. • Preliminary un-calibrated AMSR2 L1B product has been delivering to JMA since Sep. 3, 2012. O-B Monitoring of AMSR2 is ongoing. A pre-processor for the data assimilation is being developed.

  8. Microwave Imager data’s coverage in JMA NWP Global DA Meso scale DA 06UTC 18UTC AMSR2 is a unique Microwave Imager in PM Orbit. The data fill the gap in the 6-houly global data coverage. In Meso scale DA system, 06UTC and 18 UTC analysis has little microwave imager data. The data cut-off time for the receiving is 50 min. after the analysis time. Direct receiving AMSR2 data by JAXA can be used in real time. Light blue: AMSR2

  9. Development of pre-processor for AMSR2 radiance assimilation • Main function • Data thinning and ocean data selection • Removal of cloud and rain affected data →Clear sky radiance assimilation • QC with TPW and CLW retrievals • TPW: Consistency check of retrieval and NWP model • CLW: Cloud and rain screening. Used as one of predictors of variational bias correction • Scan position dependent bias correction (static) • Radiative transfer calculation with NWP model’s profiles (RTM: RTTOV-10.2) • Monitoring of AMSR2 data quality with O-B. • The biases in O-B are corrected by variational bias correction scheme (VarBC). The biases are estimated using a linear function with some predictors and those coefficients are optimized in the analysis and updated every analysis cycle. Bias correction term is in the observation operator Predictors : TPW, SST, SST^2, SSW, CLW, ORBIT,CONST

  10. Preliminary O-B Comparison with other MW imagersTMI and AMSR-E(ocean and clear sky condition) Red: W BC Green: WO BC AMSR2 19V 23V 37V 89V July 2012 ME5.02 0.03 STD 1.651.61 ME5.62 0.09 STD 2.432.45 ME3.63 0.02 STD 1.69 1.55 ME2.95 0.05 STD 2.342.20 [K] TMI Ver.7 ME1.22 -0.10 STD 1.551.48 ME-0.31 -0.15 STD 2.272.20 ME-0.63 -0.09 STD 1.29 1.27 ME0.47 -0.12 STD 1.76 1.71 July 2011 AMSR-E ME1.67 -0.06 STD 1.43 1.38 ME1.44 -0.11 STD 2.12 2.14 ME0.14 -0.06 STD 1.331.31 ME-0.67 -0.1 STD 2.152.11

  11. Preliminary O-B Comparison with other MW imagersSSMIS(ocean and clear sky condition) Red: W BC Green: WO BC AMSR2 19V 23V 37V 89V July 2012 ME5.02 0.03 STD 1.651.61 ME5.62 0.09 STD 2.432.45 ME3.63 0.02 STD 1.69 1.55 ME2.95 0.05 STD 2.362.20 [K] SSMISF-18 ME-0.29 0.01 STD 1.431.36 ME0.64 0.02 STD 2.272.14 ME-0.71 0.01 STD 1.29 1.28 ME-2.08 -0.01 STD 1.98 1.50 SSMISF-16 ME1.03 -0.06 STD 1.52 1.41 ME1.80 -0.10 STD 2.39 2.20 ME0.36 -0.06 STD 1.291.26 ME-0.55 -0.10 STD 1.951.53

  12. Preliminary L1B Comparison between AMSR2 and AMSR-E One month O-B orbit dependent bias July 2012 AMSR2 19V 23V 37V 89V Descending [K] Ascending July 2010 AMSR-E 19V 23V 37V 89V Latitude Local Time

  13. Preliminary assimilation experiment (single case) Q925 AMSR2 19GHz V-pol. O-B Q925 analysis increment AMSR-2 data assimilation experiments are in preparation.

  14. Summary • Microwave imagers data have large positive impacts in JMA NWP system. The data are essential for accurate humidity analyses and precipitation forecasts for Japan. • Current satellite microwave observing configuration is not optimal for NWP. Due to no PM orbit microwave imager, the data sparse area and period exist. AMSR2 can fill the gap. • JMA and JAXA started collaboration in Cal/Val activities for the early use of AMSR2 data in JMA NWP system. • Preliminary un-calibrated AMSR2 L1B data show positive biases in the comparison with calculated Tb. And our bias correction scheme can correct the bias globally. AMSR2 bias corrected O-B departure are comparable with other MW imager data (F16, F18 SSMIS and TMI). • AMSR2 orbit dependent bias looks different from AMSR-E. • Preliminary assimilation experiment (single case) was performed. Global and Meso scale data assimilation experiments are planned to confirm the impacts of AMSR2 data assimilation for the weather forecast.

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