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

Entry ID: NCAR_DS127.0

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Summary

Abstract: 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. 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 320x160 regular Gaussian grid. (These are designated as SURFACE, or SURFACE/SINGLE LEVEL, or SFC/sfc, variables below.) 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 of 9.999e+20 occurs in the sea surface temperature and sea ice (SSTK and CI) 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. 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 320x160 regular Gaussian grid. (These are designated as OTHER, or othr, 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. 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 4-D VAR (as apposed to 3-D VAR in ERA-40). ECMWF will continue to run the ERA-Interim model in near real time thru at least 2010, and possibly longer. This data is available in ds627.0 [http://rda.ucar.edu/datasets/ds627.0].

Related URL

Link: GET SERVICE

Description: Marine Science Data Search

Geographic Coverage

(Click for Interactive Map)

Spatial coordinates

N: -40.0

S: -70.0

E: 160.0

W: 120.0

Data Set Citation

Dataset Release Date: 2001-12-17

Parent DIF

This data set description is a member of a collection. The collection is described in
underway_ship_data

Temporal Coverage

Start Date: 2001-10-28

Stop Date: 2001-12-13

Location Keywords

OCEAN > SOUTHERN OCEAN

GEOGRAPHIC REGION > POLAR

Science Keywords

ATMOSPHERE > ATMOSPHERIC TEMPERATURE > AIR TEMPERATURE

ATMOSPHERE > ATMOSPHERIC WATER VAPOR > HUMIDITY

ISO Topic Category

CLIMATOLOGY/METEOROLOGY/ATMOSPHERE

ELEVATION

OCEANS

Platform

SHIPS

R/V AA > R/V Aurora Australis

Quality See the Marine Science Support Data Quality and Programmer's Reports at the Related URL section.

Please see the Marine Science Support Data Quality Report via the Related URL section.

Where data for a particular sensor do not exist for a particular time, the last known value is used unless the sensor has been disabled or has encountered an error. For example, some sensors only record data every minute, but the resolution for the underway dataset is 10 seconds, so the same value will be used 6 times a minute. No averages are taken for sensors that capture data at a rate other than every 10 seconds. Instead, each record will be a snapshot of each sensor at that time.

Access Constraints Data are available online via the Australian Antarctic Division Data Centre web page.

Use Constraints This data set conforms to the PICCCBY Attribution License
(http://creativecommons.org/licenses/by/3.0/).

Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=200102030 when using these data.

Ancillary Keywords

BATHYMETRY

MARINE

METEOROLOGY

OCEANOGRAPHY

Data Set Progress

COMPLETE

Originating Center

Australian Antarctic Division

Data Center

Australian Antarctic Data Centre, Australia

Data Center URL: http://data.aad.gov.au

Data Center Personnel
Name: DATA OFFICER AADC Phone: +61 3 6232 3244 Fax: +61 3 6232 3351 Email: metadata at aad.gov.au Contact Address: Australian Antarctic Division 203 Channel Highway City: Kingston Province or State: Tasmania Postal Code: 7050 Country: Australia