Identification

Title

ERA40 T85 Analysis Fields on Pressure Surfaces, created at NCAR

Alternative title(s)

d124001

Abstract

<p>The ECMWF Re-Analysis (ERA40) is a global atmospheric analysis of many conventional observations and satellite data streams for the period September 1957 to August 2002. There are numerous data products that are separated into dataset series based on resolution, vertical coordinate reference, and likely research applications.</p> <p> DS124.1 represents a new data set implemented and computed by NCAR's Data Support Section, and forms a substantial part of ongoing efforts to produce an archive of selected segments of ERA-40 on a standard transformation grid. In this case, ERA-40 upper air variables on 23 pressure levels have been transformed from either spherical harmonics (geopotential, temperature, vertical pressure velocity, vorticity, divergence, relative humidity), or a reduced N80 Gaussian grid (potential vorticity, specific humidity, ozone mass mixing ratio), to a 256 by 128 regular Gaussian grid at T85 spectral truncation. In addition, horizontal wind components have been derived from spectral vorticity and divergence and also archived on a T85 Gaussian grid. All fields are available four times per day (00,06,12 and 18 UTC). All scalar fields have been transformed using routines from the ECMWF EMOS library, whereas the horizontal winds have been obtained using NCAR's SPHEREPACK library. 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 <a href="https://www.cesm.ucar.edu/models/atm-cam/">Community Atmosphere Model (CAM)</a> component of NCAR's Community Climate System Model (CCSM).</p> <p>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 <a href="https://rda.ucar.edu/datasets/ds627.0/">ds627.0</a>. </p>

Resource type

dataset

Resource locator

https://gdex.ucar.edu/datasets/d124001/

protocol: https

name: Dataset Description

description: Related Link

function: information

https://gdex.ucar.edu/datasets/d124001/dataaccess/

protocol: https

name: Data Access

description: Related Link

function: download

Unique resource identifier

code

codeSpace

Dataset language

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

climatologyMeteorologyAtmosphere

Keywords

Keyword set

keyword value

dataset

originating controlled vocabulary

title

reference date

date type

revision

effective date

2021-03-30

Keyword set

keyword value

ERA40DAS > ERA40 Data Assimilation System

MODELS > MODELS

originating controlled vocabulary

title

reference date

date type

revision

effective date

2025-10-03

Keyword set

keyword value

ERA40 > ECMWF ERA40 Reanalysis Project

originating controlled vocabulary

title

reference date

date type

revision

effective date

2025-10-03

Keyword set

keyword value

EARTH SCIENCE > ATMOSPHERE > AIR QUALITY > TROPOSPHERIC OZONE

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR INDICATORS > HUMIDITY

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > UPPER LEVEL WINDS

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > VERTICAL WIND VELOCITY/SPEED

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > VORTICITY

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC TEMPERATURE > UPPER AIR TEMPERATURE

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WINDS > WIND DYNAMICS > CONVERGENCE

originating controlled vocabulary

title

reference date

date type

revision

effective date

2025-10-03

Geographic location

West bounding longitude

-180.0

East bounding longitude

180.0

North bounding latitude

88.928

South bounding latitude

-88.928

Temporal reference

Temporal extent

Begin position

1957-09-01T0000+00

End position

2002-08-31T1800+00

Dataset reference date

date type

publication

effective date

2005-01-05

Frequency of update

notPlanned

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Downloading/Accessing data from this dataset implies acceptance of ECMWF's Terms of Use [https://apps.ecmwf.int/datasets/data/era40-daily/licence/]

Limitations on public access

None

Responsible organisations

Responsible party

organisation name

email address

datahelp@ucar.edu

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact

organisation name

NSF NCAR Geoscience Data Exchange

email address

datahelp@ucar.edu

web address

https://gdex.ucar.edu

name: NSF NCAR Geoscience Data Exchange

description: The Geoscience Data Exchange (GDEX), managed by the Computational and Information Systems Laboratory (CISL) at NSF NCAR, contains a large collection of meteorological, atmospheric composition, and oceanographic observations, and operational and reanalysis model outputs, integrated with NSF NCAR High Performance Compute services to support atmospheric and geosciences research.

function: download

responsible party role

pointOfContact

Metadata date

2025-10-09T01:20:39Z

Metadata language