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CWB M idterm Review 2011

CWB M idterm Review 2011. Forecast Applications Branch NOAA ESRL/GSD. New STMAS surface analysis software. A new version of STMAS surface analysis system is installed in CWB in May, 2011; It is multivariate, flow-, terrain, land-water dependent;

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CWB M idterm Review 2011

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  1. CWB Midterm Review 2011 Forecast Applications Branch NOAA ESRL/GSD

  2. New STMAS surface analysis software • A new version of STMAS surface analysis system is installed in CWB in May, 2011; • It is multivariate, flow-, terrain, land-water dependent; • It processes CWB observation datasets considering terrain differences between obs stations and analysis grid height; • Constraints will be added in the next upgrade.

  3. Surface Observation Quality Control • Standard deviation QC check is added; • When temperature, dew-point and station pressure observations are available, the pressure is reduced to the analysis grid height; • When temperature and dew-point obs are not available, an option of using model background for pressure adjustment; • STMAS new 3D/4D will solve this issue.

  4. Standard Deviation from the background After applied the pressure Adjustment, the standard Deviation from background Raw CWB station pressure obs Standard deviation from bkgd These stations do not have either temperature or dewpointobs

  5. Options For terrain difference is too large (50m?), QC these pressure data (removed, see figure); Use background temperature and dewpoint to adjust the station pressure Background adjustment helps reduce the deviation but is not as good the observation adjustment

  6. Analysis increment comparison Adjusted With no Height check (50m) No adjust Adjusted With Height check (50m) Adjusted With bkgd

  7. Comparison with the current STMAS surface analysis: Better terrain/land-water usage and flow dependent

  8. Specific Humidity Issue • STMAS 3D uses LAPS cloud, hotstart and balance packages temporarily; • STMAS full 3D-4D variational cloud, hotstart and balance are under development; • Issues on specific humidity appear, showing zero SH at 950, or low heights; • Thorough debugging and testing show that the problems come from the LAPS humidity and balance packages. • Temporary solutions are recommended for CWB and two independent analysis and forecast domains are set up at GSD for comparison, one with LAPS balance and the other without LAPS balance; • Both CWB and GSD runs show slightly better forecasts without using LAPS balance package.

  9. STMAS analyses With the LAPS balance Without the LAPS balance

  10. Specific humidity 3h forecasts With the LAPS balance Without the LAPS balance

  11. Wind speed 3h forecasts Comparing to the observations, both forecasts are good; With the LAPS balance Without the LAPS balance

  12. STMAS Reflectivity Analysis: Morakot • A reflectivity analysis operator has been implemented for STMAS 3-4D analysis; • STMAS 3-4D is applied to Morakot Typhoon case again for evaluating precipitation forecasts; • It is found that a better wind forecast from STMAS helps its precipitation forecast comparing to LAPS WRF forecast (identical setup but only analyses are from STMAS or LAPS).

  13. Radar reflectivity impact (6 hr) WRF initialized by LAPS without reflectivity WRF initialized by LAPS with reflectivity Cumulative precipitation obs (6h)

  14. Precipitation Forecasts (6 hr) WRF initialized by STMAS with GFS at boundary WRF initialized by LAPS with GFS at boundary Lighter precipitation Cumulative precipitation obs (6h)

  15. Morakot: Reflectivity Analyses LAPS analysis STMAS analysis

  16. Wind forecasts at 1h • The reflectivity analyses of • LAPS and STMAS are quite • similar; • Wind forecasts from both • analyses are examined; • The one hour wind forecasts • show relatively good typhoon • structures, both from LAPS • and STMAS LAPS STMAS

  17. Wind forecasts at 6h LAPS STMAS

  18. Impact by STMAS multigrid levels STMAS has been tested with different numbers of multigrid levels, 2 multigrid levels vs. 3 levels Difference of these analyses STMAS with 2 multigrid levels STMAS with 3 multigrid levels

  19. Impact by microphysics STMAS has been tested with a WRF with different microphysics, WSM5 vs. WDM 6 WSM5 WDM6

  20. Preliminary conclusions • The radar reflectivity improves precipitation forecasts; • The wind analysis is quite important for precipitation forecasts; • Multigrid improves the forecasts; • Different microphysics schemes affect the forecast in detailed precipitation but not as much as the wind analysis; • Different boundary conditions has some impacts as well. All are preliminary and further study will be needed in term of analysis schemes, microphysics and boundary conditions.

  21. Outlook for the remaining tasks • Hotstart is under development (working with CWB and resolve issues with the LAPS hotstart and balance issues); • Cycling issues are being investigated and the lateral boundary plays an important role (working with CWB on fixing a boundary consistency issue); • Downscaling: more case studies have been done and looking for potential typhoon cases for CWB. • Satellite data assimilation: Test of CRTM for AMSU-A data for STMAS variational analysis using CRTM K-matrix.

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