NCAR Resarch Data Archive logo

ERA40 T85 Monthly Mean Analysis Fields on Model Levels, created at NCAR

| DOI: 10.5065/D6ST7MW3

This historical dataset is recommended for ancillary use only and not as a primary research dataset. It has likely been superseded by a newer, improved dataset.


DS126.2 represents a dataset implemented and computed by NCAR's Data Support Section, and forms an essential part of efforts undertaken in late 2004, early 2005, to produce an archive of selected segments of ERA-40 on a standard transformation grid. In this case, ERA-40 monthly mean upper air variables on 60 model levels were transformed from either spherical harmonics (surface geopotential, temperature, vertical pressure velocity, vorticity, logarithm of surface pressure, divergence), or a reduced N80 Gaussian grid (specific humidity, ozone mass mixing ratio, cloud liquid water content, cloud ice water content, cloud cover), to a 256 by 128 regular Gaussian grid at T85 spectral truncation. In addition, horizontal wind components were derived from spectral vorticity and divergence and also archived on a T85 Gaussian grid. All scalar fields were transformed using routines from the ECMWF EMOS library, whereas the horizontal winds were obtained using NCAR's SPHEREPACK library. All corresponding 00Z, 06Z, 12Z, and 18Z monthly mean upper air variables on 60 model levels were also transformed to a T85 Gaussian grid. The choice of a T85 Gaussian grid was based on considerations of limiting the volume of new data generated to a moderate level, and to match the horizontal resolution of the Community Atmosphere Model (CAM) component of NCAR's Community Climate System Model (CCSM).

The ERA-Interim data from ECMWF is an update to the ERA-40 project. The ERA-Interim data starts in 1989 and has a higher horizontal resolution (T255, N128 nominally 0.703125 degrees) than the ERA-40 data (T159, N80 nominally 1.125 degrees). ERA-Interim is based on a more current model than ERA-40 and uses 4DVAR (as opposed to 3DVAR in ERA-40). ECMWF will continue to run the ERA-Interim model in near real time through at least 2010, and possibly longer. This data is available in ds627.0.

Temporal Range:
1957-09-01 00:00 +0000 to 2002-08-31 18:00 +0000 (Entire dataset) Period details by dataset product
Usage Restrictions:

Downloading/Accessing data from this dataset implies acceptance of ECMWF's Terms of Use

Cloud Frequency Cloud Liquid Water/Ice Convergence Humidity
Surface Pressure Tropospheric Ozone Upper Air Temperature Upper Level Winds
Vertical Wind Velocity/Speed Vorticity
GRIB parameter table: HTML | XML
Vertical Levels:
See the detailed metadata for level information.
Data Types:
Spatial Coverage:
Longitude Range: Westernmost=180W Easternmost=180E
Latitude Range: Southernmost=88.928S Northernmost=88.928N Detailed coverage information
Data Contributors:
Research Data Archive, Computational and Information Systems Laboratory, National Center for Atmospheric Research, University Corporation for Atmospheric Research
European Centre for Medium-Range Weather Forecasts
Total Volume:
112.9 GB (Entire dataset) Volume details by dataset product
Data Formats:
Related RDA Datasets:
ERA-Interim Project
More Details:
View a more detailed summary of the data, including specific date ranges and locations by parameter
Metadata Record:
Data License:
Citation counts are compiled through information provided by publicly-accessible APIs according to the guidelines developed through the project. If journals do not provide citation information to these publicly-accessible services, then this citation information will not be included in RDA citation counts. Additionally citations that include dataset DOIs are the only types included in these counts, so legacy citations without DOIs, references found in publication acknowledgements, or references to a related publication that describes a dataset will not be included in these counts.