Era interim and asr data management at ncar
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ERA-Interim and ASR Data Management at NCAR. Steven Worley Dave Stepaniak Chi-Fan Shih February 17, 2009. ERA-Interim. Time Period, 1989-current T255L60 4DVAR global, spectral or reduced Gaussian Products high resolution reg. gaussian (512x256) 37 press. lvls . (1000  1)

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ERA-Interim and ASR Data Management at NCAR

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Era interim and asr data management at ncar

ERA-Interim and ASR Data Management at NCAR

Steven Worley

Dave Stepaniak

Chi-Fan Shih

February 17, 2009


Era interim

ERA-Interim

  • Time Period, 1989-current

  • T255L60 4DVAR global, spectral or reduced Gaussian

  • Products

    • high resolution

    • reg. gaussian (512x256)

    • 37 press. lvls. (10001)

    • 15 isentropic surf.

    • 30 ocn. wave anal. fields

    • 47 surface anal. fields

  • Total size ≅ 84 TB (tapes)

  • Network Access ≅ 18 TB

  • Details

    • http://www.ecmwf.int/research/era/do/get/era-interim

    • http://dss.ucar.edu/datasets/ds627.0/ (to be here)


Information sources documentation

Information sources / documentation

  • Web pages

    • http://dss.ucar.edu/datasets/ds627.0/docs/


Ifs @ ecmwf

IFS @ ECMWF

  • Chapter 14 – Data Flow

    • difference between analysis (an), 4D-Var analysis (4v), 4D-increment analysis (4i) files

    • variables coming out of the analysis

    • variables coming out of the forecasts – with reference times


Model levels and layers

Model levels and layers

  • Documented accurate method to determine model level and layer coefficients.

    • Tables and codes that provide them

    • netCDF file with values

  • Tricky matter

    • GRIB files have model layer interfaces defined, not the level

  • Contrast of ERA-15 (red) versus ERA-40 and ERA-Interim (blue)


High resolution model level data

High Resolution Model Level Data

Two forms combined define atmosphere

  • T255 spectral coefficients, Model Level Fields

    • Z, geopotential height of level 1

    • T, temperature, 60 levels

    • W, vertical velocity, 60 levels

    • VO, relative vorticity, 60 levels

    • LNSP, log. of surface pressure

    • D, divergence, 60 levels

  • N128 reduced Gaussian, Model Level Fields

    • Q, specific humidity, 60 levels

    • O3, ozone mass mixing ratio, 60 levels

    • CLWC, cloud liquid water content, 60 levels

    • CIWC, cloud ice water content, 60 levels

    • CC, cloud cover, 60 levels

      dss.ucar.edu/datasets/ds627.0/docs/era_interim_grib_table.oper_an_ml.html


  • Horizontal grids ncar will compute regular gaussian 512x256

    Horizontal GridsNCAR will compute Regular Gaussian (512x256)

    N128

    512x256


    Era interim and asr data management at ncar

    Regular Gaussian (512x256)

    Transform to aid users

    • N128 Reduced Gaussian  Regular Gaussian

    • T255 Spectral  Regular Gaussian

    • U and V winds are computed from VO and D

      Products to be transformed

    • Analyses on model levels (ml), surface (sfc), pressure levels (pl), isentropic levels (pt), and potential vorticity levels (pv).

  • Note: Important fields are in the forecast files

    • Transform only selected fields and forecast intervals


  • Surface forecast grids model resolution

    Surface Forecast Grids – Model resolution

    • Initialization every 12 hours

    • Generally, out to 240 hours

      • 3,6,9,12,15,18,21,24,30,36,42,48,60,72,84,96,108,120,132,144,156,168,180,192,204,216,228,240

    http://dss.ucar.edu/datasets/ds627.0/docs/era_interim_grib_table.oper_fc_sfc.html


    Regular gaussian 512x256 continued

    Regular Gaussian (512x256), continued

    What high resolution data will ASR use?

    • N128 and T255 spectral model level orregular Gaussian model level data created at NCAR?

      If regular Gaussian, then:

    • We expect ASR to use the analysis (an) files.

    • We will extract some fields from the forecast (fc) files.

    • Are there any fields in the ‘fc’ files that you need?

    • Planning just one pass on the ‘fc’ files to create regular Gaussian

      Let’s get coordinated soon!


    Regular gaussian 512x256 continued1

    Regular Gaussian (512x256), continued

    • Surface and Single level analysis (N128)

      • 47 fields

      • http://dss.ucar.edu/datasets/ds627.0/docs/era_interim_grib_table.oper_an_sfc.html


    Status @ ncar

    Status @ NCAR

    • All products for January 1989

      • High resolution transformations (reg. gaussian)

    • Decision still to be made on fields coming from the forecasts


    Status @ ncar1

    Status @ NCAR

    • Within a product there are 6-hourly synoptic files

    • Our recommendation – if you plan to work with regular Gaussian model level fields

      ASAP begin working with the January 1989 data

      • Examine the model level and surface level analyses.

      • Examine forecasts for additional fields that ASR might need.

        Documents, metadata tables, test data (on NCAR/MSS)

        http://dss.ucar.edu/datasets/ds627.0/docs/

        /DSS/DS627.0/ei.oper.an.ml/198901/ei.oper.an.ml.regn128sc.1989010100

        /DSS/DS627.0/ei.oper.an.ml/198901/ei.oper.an.ml.regn128uv.1989010100

        /DSS/DS627.0/ei.oper.an.sfc/198901/ei.oper.an.sfc.regn128sc.1989010100

        /DSS/DS627.0/ei.oper.fc.sfc/198901/ei.oper.fc.sfc.regn128sc.1989010100

        /DSS/DS627.0/ei.oper.fc.sfc/198901/ei.oper.fc.sfc.regn128sc.1989010112


    Status

    Status

    Future

    • December 2007 data will arrive next

      • Delivery – probably, mid-March, 2009

    • Receive and process 1989 – 2007

    • Receive 2008, about August, 2009

    • 2009 updates by network transfer

      • Lagging about 3 months behind real time @ ECMWF

    • Establish the RDA online service. Product suite TBD

    • All data will be on the NCAR MSS

    • How will ASR get a copy of ERA-Interim?


    Asr data management at ncar

    ASR Data Management at NCAR

    • Managed a component in the NCAR/CISL Research Data Archive (RDA)

      • http://dss.ucar.edu/index.html

    • Planning for about 55 TB total (?)

    • Duplicate copies on the NCAR MSS

    • All data available to the public (?)

      • usage restriction?

    • 5-7 TB online, network access (TBD)

    • Follow template used for JRA-25

      • http://dss.ucar.edu/datasets/ds625.0/


    What we need to know

    What we need to know

    • Was there a proposed data management plan?

      • Is a product model like ERA-Interim suitable

        • e.g. ml, pl, sfc, forecasts, etc. ?

    • Will the netCDF file metadata be CF compliant?

      • Good idea, enables tool compatibility

    • How will the data files be structured?

      • Synoptic 3-hourly

      • Single variable time series


    What we need to know1

    What we need to know

    • How to deal with the 2x horizontal resolution and polar projection?

      • What interpolations from model coordinates will be done?

    • Will pressure level data be computed?

    • Will time averages be computed

      • e.g. monthly means

    • Will model assimilation feedback be added to the observations used, should that data be archived? In what format?


    What we need to know2

    What we need to know

    • What other organization will host ASR data?

      • We must not duplicate efforts

    • How will we get the data to NCAR?

      • Tapes, TB disks, network?

    • Who will provide other organization bulk data delivery?

    • How do we handle re-runs and fixes?


    Contacts

    Contacts


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