Identification

Title

ERA40 T106 6-hourly Surface Analysis and Surface Forecast Fields, created at NCAR

Alternative title(s)

d127000

Abstract

<p>DS127.0 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 standard transformation grids.</p> <p> In this case, forty six ERA-40 6-hourly surface and single level analysis variables were transformed from a reduced N80 Gaussian grid to a 320 by 160 regular Gaussian grid. All fields were transformed using routines from the ECMWF EMOS library, including 10 meter winds which were treated as scalars because of a lack of 10 meter spectral vorticity and divergence. A missing value occurs in the sea surface temperature and sea ice fields to mask grid points occurring over land. Fields formerly archived as whole integers, such as vegetation indices and cloud cover, occur as integers plus a fractional part in the T106 version due to interpolation.</p> <p> In addition, twenty seven ERA-40 6-hourly surface and single level 6-hour forecast variables were transformed from a reduced N80 Gaussian grid to a 320 by 160 regular Gaussian grid. (These are designated as OTHER, or other, variables below.) All variables are valid 6 hours after the forecast was initiated. Thus, 00Z 6-hour forecast evaporation is valid at 06Z. Four of the variables are instantaneous variables, and the remaining twenty three variables are accumulated over the 6-hour forecast time. Divide the accumulated variables by 21600 seconds to obtain instantaneous values. (Multiplication by minus one may also be necessary to match the sign convention one is accustomed to.) All fields were transformed using routines from the ECMWF EMOS library, including three pairs of stresses which were treated as scalars because of a lack of spectral precursors.</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/d127000/

protocol: https

name: Dataset Description

description: Related Link

function: information

https://gdex.ucar.edu/datasets/d127000/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

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > OUTGOING LONGWAVE RADIATION

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > HEAT FLUX

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > LONGWAVE RADIATION

EARTH SCIENCE > ATMOSPHERE > ALTITUDE > PLANETARY BOUNDARY LAYER HEIGHT

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC PRESSURE > GRAVITY WAVE

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > INCOMING SOLAR RADIATION

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC RADIATION > SHORTWAVE RADIATION

EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > SOLID PRECIPITATION > SNOW

EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR PROCESSES > EVAPORATION

EARTH SCIENCE > ATMOSPHERE > PRECIPITATION > PRECIPITATION AMOUNT

EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SNOW/ICE > SNOW MELT

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

EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SURFACE WATER > SURFACE WATER PROCESSES/MEASUREMENTS > RUNOFF

originating controlled vocabulary

title

reference date

date type

revision

effective date

2025-10-03

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

1957-09-01T0000+00

End position

2002-08-31T1800+00

Dataset reference date

date type

publication

effective date

2005-08-04

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

2025-10-09T01:20:46Z

Metadata language