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Observation processing
See the Observation Data Base documentation.
Data assimilation
Chapter 1: Overview
Chapter 2: 4D variational assimilation
Chapter 3: Tangent-linear physics
Chapter 4: Background term
Chapter 5: Observation operators and observation cost function (Jo )
Chapter 6: Background, analysis and forecast errors
Chapter 7: Gravity-wave control
Chapter 8: Diagnostics
Chapter 9: Observation processing
Chapter 10: Observation screening
Chapter 11: Land-surface analysis
Chapter 12: Analysis of sea-ice concentration and sea surface temperature
Chapter 13: Data flow
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Dynamics and numerical procedures
Chapter 1: Introduction
Chapter 2: Basic equations and discretization
Chapter 3: Semi-Lagrangian formulation
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Physical processes
Chapter 1: Overview
Chapter 2: Radiation
Chapter 3: Turbulent transport and interactions with the surface
Chapter 4: Subgrid-scale orographic drag
Chapter 5: Non-orographic gravity wave drag
Chapter 6: Convection
Chapter 7: Clouds and large-scale precipitation
Chapter 8: Surface parametrization
Chapter 9: Methane oxidation
Chapter 10: Ozone chemistry parametrization
Chapter 11: Climatological data
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Ensemble Prediction System
Chapter 1: Methodology
Chapter 2: Computational details: initial perturbations
Chapter 3: Computational details: non-linear integrations
References
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Technical and Computational Procedures
Chapter 1: Structure, data flow and standards
Chapter 2: Parallel implementation
Appendix A: Structure, data flow and standards
Appendix B: Message Passing Library (MPL)
Appendix C: The TRANS package
Appendix D: FullPos user guide
Appendix E: FullPos technical guide
Appendix F: Coding standards
Appendix G: The Perforce source code management system user guide
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Wave Model
Chapter 1: Introduction
Chapter 2 The kinematic part of the energy balance equation
Chapter 3 Parametrization of source terms and the energy balance in a growing wind sea
Chapter 4 Data assimilation in WAM
Chapter 5 Numerical scheme
Chapter 6 WAM model software package
Chapter 7 Wind wave interaction at ECMWF
Chapter 8 Extreme wave forecasting
Chapter 9 Second-order spectrum
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Meteorological Changes
- Background error variances from the ensemble of data assimilations (EDA) used by the deterministic 4D-Var assimilation
- Improvements to cloud scheme formulation
- Changes to all-sky assimilation of microwave data
- Reduction of AMSU-A observation errors and adjustments to MODIS AMVs
- Accounting for tangent point drift in GPS radio occultation
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The EMOS library GRIBEX routine cannot handle GRIB-2 fields. In order to be able to handle both GRIB-1 and GRIB-2 fields, it is recommended to use grib_api. Download the latest version of the grib_api library
EMOSLIB
In order to be able to interpolate GRIB-2 fields, users must upgrade to version 000381 (released on 22 March 2011) or higher of EMOSLIB.
Second-order packing
Encoding of second order packed data in GRIB-1 and GRIB-2 has been implemented in version 1.9.8 of grib_api.
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The latitudes and longitudes for each grid point can be obtained from grib_api with high accuracy using the keys latitudes, longitudes, distinctLatitudes, distinctLongitudes or using the grib_get_data Fortran functions or the grib_iterator C functions.
As grib_api is computing latitudes and longitudes from the order N of the Gaussian grid the values are identical in both editions and they are very accurate. Definitions of the various Gaussian grids in use at ECMWF can be found here.
Coding of negative longitude values in GRIB-2
According to the WMO FM-92 GRIB edition 2, only positive values of longitudeOfFirstGridPoint, longitudeOfLastGridPoint, longitudeOfSouthernPole are allowed. Negative values of longitudeOfFirstGridPointInDegrees, longitudeOfLastGridPointInDegrees, longitudeOfSouthernPoleInDegrees are converted by grib_api to positive values by adding 360 to the value before encoding.
Conversion
Please see GRIB edition 1 to 2 conversion. GRIB-2 to GRIB-1
PrepIFS experiments
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