Effective Atmospheric Angular Momentum (EAAM)

General Info

Title:	Effective Atmospheric Angular Momentum (EAAM)
Type:	Data Entity
Sub-Type:	Measurement
Abbreviation:	EAAM
Publication State:	published
The publication state of this metadata: 'old' - for redundant records; 'working' - for new/in progress records; 'published' - for records approaching maturity, which may still change, but should be available via the discovery services; and 'Published' for mature records that are unlikely to change and should be available via the discovery services.

URI:	http://badc.nerc.ac.uk/view/badc.nerc.ac.uk__ATOM__dataent_EAAM

Summary
A brief description of the data.

Data from the Met Office and the European Centre for Medium Range Weather Forecasting (ECMWF) models. Data are 3 angular momentum components of the mass and wind terms at 12 or 24 hourly intervals. ECMWF data available 1979-93. Met Office data available 1983-1997. This dataset is public.

Content
The actual data being described by this document. NB, in the case of data granules, this content may just be a reference to an ingested CSML or CDML file.

Introduction

Atmospheric Angular Momentum (AAM) plays a significant role in causing variations in the length of day. Study of AAM can also yield information about the Earth's orientation in space and the large scale behaviour of the atmosphere.

The BADC stores AAM data from the Met Office and the European Centre for Medium Range Weather Forecasting (ECMWF). The data are available as ASCII files containing values of the 3 angular momentum components at 12 or 24-hourly intervals, from 1979 to 1997 and can be obtained via this World Wide Web interface or by anonymous FTP.

Data Access

This dataset is public and can be accessed from the BADC archives. Please acknowledge the source of the data in any publication.

Access to Data - File Format

They are stored in ASCII (plain text and "human" readable) tables which can be displayed on your web browser and then "saved" on to your computer.

Specific information relative to temporal coverage, parameters and the AAM data file format is available.
A guide explains how to acquire the AAM data from the BADC and also how to read the data files.

Documentation, Links to further information and references

General information about the Atmospheric Angular Momentum has been compiled to provide scientific background on the subject.

There are four historical AAM datasets:

AAM (NMC) - National Meteorological Center
AAM (JMA) - Japanese Meteorological Agency
AAM (UKMO) - Met Office
AAM (ECMWF) - European Centre for Medium-Range Weather Forecasting

The most complete archive of AAM data are held by the International Earth Rotation Service's (IERS) Special Bureau for the Atmosphere (SBA).

Effective Atmospheric Angular Momentum Functions data from the Met Office (1986 to present day) and from ECMWF (1988 to present day) may also be directly downloaded from the anonymous FTP service at ftp.aer.com, together with relative documentation. AAM data from NMC and JMA can also be found at this FTP site.

Should you wish to know more about the AAM data, there is a set of useful references which provide more comprehensive information.

Citation

Date of citation

Who to contact

You can contact David Salstein at the SBA for more information. David Salstein is located at Atmospheric and Environmental Research (AER).

If you have queries about these pages or about obtaining the AAM data from the BADC then you should contact BADC Support. Your query should be answered within one working day. When follow-up work is required, the BADC support will carry out the work as quickly and efficiently as possible, and in any case, the user will be kept informed of progress.

Lineage
Summary of the origins of the dataset, e.g.: "Dataset produced from NASA MODIS instrument on Terra and collected at the University of York's groundstation 1999-2003 and a copy provided to NEODC in June 2007".

Data files acquired as is from the IERS.

Quality Statement
Description of the relative quality of the dataset.

Unknown.

Author
The principal author of the actual underlying data. Only one author can be specified per atom; if there are multiple authors, these should be specified as 'contributors'. NB, an atom MUST have an author specified.

Name	email
Met Office and ECMWF

Online References
Online references with a specific relationship to the data being described here. NB, if links are supplied they must be valid and include the transport protocol - e.g. 'http://blah.co.uk'. Also, note, three online references can be added at once; after these are added a further three may be specified - and so on.

Relation	Title
Download	EAAM Data Directory
Logo	Met Office Logo
Documentation	BADC Doc: Scientific Background Information
Documentation	BADC Doc: EAAM Data File Format
Documentation	IERS Special Bureau for the Atmosphere (SBA) website
Documentation	BADC Doc: EAAM Data Helpfile
Documentation	BADC Doc: EAAM List of References
Documentation	International Earth Rotation and Reference Systems Service Website

Parent Data Entity
Define the parent of this record. There should probably only be one parent, but this is not enforced.

No data specified at present

Sub Data Entities
Lists all entities which have the current entity as their parent.

None

Associated Deployments

Parameters - summary

ANGULARMOMENTUM	VORTICITY	ATMOSPHERICWINDS	ATMOSPHERE
EARTH SCIENCE	NULL

Parameters - details
Parameters to describe the data - with vocab URL and term IDs for further classification. Note, three parameters can be added at once; after these are added a further three may be specified - and so on.

Label	Vocab Term URL	Vocab Term ID
ANGULARMOMENTUM	http://vocab.ndg.nerc.ac.uk/term/null	NULL
VORTICITY	http://vocab.ndg.nerc.ac.uk/term/null	NULL
ATMOSPHERICWINDS	http://vocab.ndg.nerc.ac.uk/term/P141	NULL
ATMOSPHERE	http://vocab.ndg.nerc.ac.uk/term/P131	NULL
EARTH SCIENCE	http://vocab.ndg.nerc.ac.uk/term/P111	GCAT0001
NULL	general_units	0

Data Coverage
Summary of the temporal and spatial data coverage for the data.

Spatial coverage
Max Y: 90.0
Min X: -180.0	Max X 180.0
Min Y -90.0

Temporal coverage
Start Date:	1979-01-01
End Date:	1997-01-31

Spatial resolution

No spatial resoultion information available.

Vertical extent

No vertical extent information available.

Responsible Parties
Parties responsible for the metadata - e.g. data curator. Responsible parties can have a role specified to make their function clearer. Multiple responsible parties can be specified.

Role	Name	URI
Data Curator	badc.nerc.ac.uk	http://badc.nerc.ac.uk

Other Info
Other miscellaneous information. Note, update frequency relates to the update frequency of the underlying data, not the metadata.

Dataset language

English

Update frequency

irregular

Links and Services
	Downloadable XML version of this record

Not all information in this record may be rendered in this view. Please see the XML version for complete content

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