THE NCEP REAL-TIME MESOSCALE ANALYSIS (RTMA) .ppt

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1、THE NCEP REAL-TIME MESOSCALE ANALYSIS (RTMA),Manuel Pondeca, Geoff Manikin , David Parrish, James Purser, Geoff DiMego, Stan Benjamin, John Horel, Lee Anderson, Brad Colman, Greg Mann, and Greg MandtMesoscale Modeling Branch National Centers for Environmental PredictionManuel.Pondecanoaa.gov 301-763

2、-8000 ext 7734NOAA Science Center-Room 207 5200 Auth Road Camp Springs, MD 20746-4304,Topics,The need for an Analysis of Record (AOR) and the Proposed Three Phase Implementation PlanThe Real-Time Mesoscale Analysis (RTMA): Phase-I of the AOR The Mechanics of the RTMA GSI-2DVar Precipitation fields S

3、ky cover fieldsCurrent and Future Work,Analysis of Record,A comprehensive set of the best possible analyses of the atmosphere at high spatial and temporal resolution with particular attention placed on weather and climate conditions near the surface,Critical need for AOR at NOAA NWS!,Analysis of Rec

4、ord (AOR) Summary of Need,In part needed to: Meet the NDFD production requirement -a minimum analysis with a grid spacing of 5-km and temporal frequency of one hour. Provide analyses to verify NDFD gridded forecasts Enhance Mesoscale Modeling efforts Establish a benchmark climate analysis for use in

5、 regional and local climate change studies Enhance Representativeness of Physical Driving in Dispersion modeling (eg. for transport of hazardous materials). Enhance Aviation and sfc transportation management efforts Enhance Coastal zone and fire management efforts,AOR: Three Phase Program,August 200

6、4: Mesoscale Analysis Committee (MAC) established by Director, NWS Office of Science and Technology to implement AOR program.MULTI-PHASE APPROACH ADOPTED:Phase I Real-time Mesoscale Analysis Analyses produced hourly within 30 minutes. Time constraint is a factor. Prototype for AOR. Phase II Analysis

7、 of Record Use state-of-the-art methods to obtain best analysis possible Time constraint liftedPhase III Reanalysis Apply mature AOR retrospectively 30 year time history of AORs,Real-Time Mesoscale Analysis (RTMA),Fast-track, proof-of-concept of the AOR program. Intended to: Enhance existing analysi

8、s capabilities and generate near real-time hourly NDFD grid matching analysis of surface parameters and clouds.Also provide estimates of analysis uncertaintyEstablish benchmark for future AOR effortsDeveloped by NCEP and ESRL Running since August 2006 for CONUS. Extended toAlaska in 2007, and to Haw

9、aii and Puerto Rico in 2008.,RUC 13 Downscaled to 5km NDFD grid,First guess 2m-T, 2m-q, 10m-u and v, psfc,NDFD terrain,GSI 2DVar,Analysis Uncertainty,Observations,Stage-II Precip Interpolated to 5km NDFD grid,Sky Cover,OUTPUTin GRIB2FILE 1: 2m T, q 10m u, v, psfc FILE 2: PrecipFILE 3: Sky Cover,AWIP

10、SFTP ServerRTMA Website,CONUS RTMA PROCEDURE,Summary of the Conus RTMA,GSI-2DVar analysis of near surface parameters: Currently, T and SPH at 2m, wind at 10m, and surface pressure.Hourly 5km resolution analysis First guess: One hour 13km RUC forecast downscaled to NDFD grid Univariate analysis Terra

11、in following background error covariances Estimate of analysis error/uncertaintyPrecipitation NCEP Stage II analysisSky cover NESDIS GOES sounder effective cloud amount,RTMA First Guess / 2m T,Original 13 km,Downscaled 5 km,RTMA First Guess / 10m Wind,Original 13 km,Downscaled 5 km,Observations and

12、Quality Control,Surface Land (SYNOPTIC and METAR) Surface marine (Ship, Buoy, C-MAN, Tide Gauge) Splash-level dropsonde over ocean Surface Mesonets SSM/I Superobed wind speed over ocean QUICKSCAT winds over oceanDATA FEED Conventional through TOC Mesonets through MADIS. In Future Also Through MesoWe

13、st,Observations and Quality Control,PRE- GSI QC: MADIS QC control flags honored GSD Mesonet Wind “Provider-Uselist” GSD Mesonet Wind “Station-Uselist” Rejectlists from WFOs Dynamic RejectlistsQC Within GSI: Gross-error CheckMesonet Issues:Mesonets comprise majority of obs but they are not as good as

14、 the other conventional surface ob sources.,SURFACE TEMPERATURE OBSERVATIONS Total = 11911 ; METARS = 1678 (14. 1%) MESONETS = 9914 (83.2%) Others = 319 (2.6%),Cycle 2008081517,Anisotropic Background Error Covariance Functions,Background error covariances mapped to smoothed version of the NDFD topog

15、raphy = Restrict ob influence based on elevation differences.Implementation is based on the use of Recursive filters in grid-point space. Covariance model is a variant of the Riishojgaard model (1998, Tellus, V50A, 42-57) For details, see: Purser, Wu, Parrish and Roberts, 2003, MWR, Vol 131, p1524-1

16、535Purser, Wu, Parrish and Roberts, 2003, MWR, Vol 131, p1536-1548,Error Correlations for Valley Ob (SLC) Location Plotted Over Utah Topography,Anisotropic Correlation: obs influence restricted to areas of similar elevation,Isotropic Correlation: obs influence extends up mountain slope,RTMA Analysis

17、 Uncertainty,METHOD USED TO ESTIMATE THE ANALYSIS ERROR IS ADAPATION TO THE GSI OF THE LANCZOS METHOD DESCRIBED BY FISHER AND COURTIER (1995, Tech. Memorandum 220, ECMWF).ANALYSIS ERROR COVARIANCE MATRIX=INVERSE OF HESSIAN MATRIX IN INCREMENTAL VARIATIONAL ANALYSIS.USE BI-PRODUCTS OF THE CONJUGATE-G

18、RADIENT ALGORITHM OF THE GSI (gradient vectors and stepsizes) TO COMPUTE SUBSET OF EIGENVECTORS AND EIGENVALUES OF HESSIAN AND RECONSTRUCT LOWER-RANK REPRESENTATION OF THIS MATRIX (OR OF ITS) INVERSE.,TEMP INCREMENTS + ANALYSIS ERROR FOR 14Z 22 FEB 2008,ANAL INCREMENTS,ANAL ERROR,Temperature Analysi

19、s for 12 Z 6 Oct 2008,http:/www.emc.ncep.noaa.gov/mmb/rtma/para,NCEP RTMA Precipitation Analysis,NCEP Stage II (real-time) and Stage IV (delayed) precipitation analyses are produced on the 4-km Hydrologic Rainfall Analysis Project grid The existing multi-sensor (gauge and radar) Stage II precipitati

20、on analysis available 35 minutes past the hour RTMA is mapped to the 5 km NDFD grid and converted to GRIB2 Upgrade plan including OHD analysis + improved gauge QC from FSL Primary contact: Ying Lin, NCEP/EMC http:/wwwt.emc.ncep.noaa.gov/mmb/ylin/pcpanl/,ORIGINAL,NDFD GRIB2,Hourly Gages Available for

21、 Stage II Precipitation Analysis,Derived ECA from GOES-12,ECA from GRIB2 file 5km grid,GOES-12 IR image (11um),Effective Cloud Amount (ECA, %) Derived from GOES sounderMapped onto 5-km NDFD gridConverted to GRIB2 for NDGDContact: Robert Aune, Advanced Satellite Products Branch, NESDIS (Madison, WI),

22、(b),(a),(c),Sky Cover: Effective Cloud Amount,EXPAND NUMBER OF ANALYZED PARAMETERS: ADD CLOUD BASE, VISIBILITY AT 2m, WIND GUST AT 10m, PBL HEIGHT, etc.TURN ON BIAS CORRECTION FOR FIRST-GUESSIMPROVE FIRST GUESS, eg. HURRICANE TREATMENTTURN ON VARIATIONAL QC for ObsRUN RTMA CONUS AT 2.5km RESOLUTIONEXPAND BAKCGROUND ERROR COVARIANCE SHAPES,FUTURE PLANS,