Status of the ERA-40 Re-Analysis Archive at the BADC

This page is updated monthly to inform users of the current status of ERA-40 at the BADC.

Introduction

The BADC archives ECMWF ERA-40 Re-analysis data into two separate archives:

The standard BADC data archive (at the Rutherford Appleton Laboratory, Oxfordshire)
An archive at the Manchester High-Performance Computing Centre (maintained and updated by CGAM (Centre for Global Atmospheric Modelling) at the University of Reading).

The reason for holding two separate data archives is to meet the requirements of two distinct groups of atmospheric (and other) scientists. The standard BADC archive will serve the data using formats and utilities that the majority of earth scientists can make use of. The Manchester archive, on the other hand, is aimed specifically at users of the modelling resources held on the high-performance computing systems. This data will be mainly used by members of UGAMP (the UK universities Global Atmospheric Modelling Programme). This page gives an overview of the contents and the current status of each archive.

Links are also provided to validation information relating to ERA-40 and a latest news page for ERA-40.

Production Status

The ECMWF has now completed production of ERA-40 and all the 6-hourly data is available from the BADC. Monthly means of the data are also archived.

The data in the standard archive is held in its original GRIB format in T159 Spectral and N80 Reduced Gaussian Gridded resolutions.

The BADC is developing a new system that will allow users to access the ERA-40 dataset in a regular gridded format. This involves the conversion of spectral and reduced Gaussian gridded data when the user calls the files. The main reason for storing all the data in the spectral and reduced Gaussian forms is that these formats are considerably smaller in volume than the equivalent 1° x 1° gridded data. This allows us to hold all the data on disk.

ERA-40 data is held on the following atmospheric level types:

Surface level.
Model levels (1-60).
Pressure levels (1, 2, 3, 5, 7, 10, 20, 30, 50, 70, 100, 150, 200, 250, 300, 400, 500, 600, 700, 775, 850, 925 and 1000hPa).
Potential temperature levels (256, 275, 285, 300, 315, 330, 350, 370, 395, 430, 475, 530, 600, 700 and 850K).
Potential vorticity levels (PV = +/-2).

Details about the variables available in the BADC archive are documented on the ERA-40 parameters page. Each individual file holds one parameter at one time-step for the entire globe. A common file-naming convention has been adopted for both ERA-40 archives.

The data can be accessed using an via FTP or via our web-interface.

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The Manchester BADC ERA-40 Archive

The Manchester BADC ERA-40 archive is populated and managed by Paul Berrisford of CGAM at the University of Reading. Documentation about the archive is available from the CGAM web site. The data is being stored in both GRIB and NetCDF formats on the 128-processor Origin 2000 machine, Fermat. The files on Fermat are instantaneous but contain several fields (e.g. in the GRIB files all pressure level spectral fields are together, and in NetCDF files all pressure level fields are together). The parameters stored at Manchester are the same as those held in the standard BADC archive. Files of one type, at one analysis time, are tarred together for each available month. For example, all the 06:00 hour files are tarred into one file for January (as opposed to the standard BADC archive where each time-step has a separate file). A common file-naming convention has been adopted for both ERA-40 archives.

Queries about accessing the Manchester dataset and its contents should be directed to Paul Berrisford. Please note that you will need to register as a BADC user for ERA-40 data if you want to gain access to either of the archives.

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Links Relating to the Validation of ERA-40 data

The ECMWF web pages document data quality issues relating to ERA-40. This includes information on a probable rerun of the latter part of ERA-40 .

You can also visit the links below to access details of validation studies for ERA-40:

Modifications to the BADC archive are detailed in the latest news page.

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