Identification

Title

Aa Indices.

Abstract

The aa index is a simple global geomagnetic activity index, with units of 1 nT (nanotesla), which is produced from the K indices from two approximately antipodal observatories. At present these are Hartland observatory in the UK and Canberra observatory in Australia. The main advantage in using aa indices for research purposes is that the time series spans further back (to 1868) than any of the other planetary indices time series.Also, up to date values are produced and made available weekly, giving nearer to real time availability than any other planetary index. In between the weekly updates, BGS calculates estimated aa indices, providing real time "nowcasts" which are updated on an hourly basis. These estimates are clearly marked with the letters "Est". Although calculated by the same method, the aa indices available on this service are not the definitive values. These are published by the International Service for Geomagnetic Indices, CRPE/CNET - CNRS, 4 Avenue de Neptune, F-94107 Saint Maur, Cedex, France.

Resource type

dataset

Resource locator

http://www.geomag.bgs.ac.uk/data_service/data/magnetic_indices/aaindex.html

function: information

Unique resource identifier

code

http://data.bgs.ac.uk/id/dataHolding/13480365

codeSpace

Dataset language

eng

Spatial reference system

authority code

OGP

code identifying the spatial reference system

GLOC

Additional information source

Complete time Series. Global: Derived from 2 Antipodal Locations.

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

originating controlled vocabulary

title

GEMET - INSPIRE themes

reference date

date type

publication

effective date

2008-06-01

Keyword set

keyword value

Geomagnetism

originating controlled vocabulary

title

BGS Thesaurus of Geosciences

reference date

date type

revision

effective date

2011

Keyword set

keyword value

NERC_DDC

Geographic location

West bounding longitude

-180.0000

East bounding longitude

180.0000

North bounding latitude

90.0000

South bounding latitude

-90.0000

Extent

Extent group

authority code

title

British Geological Survey Gazetteer: Geographical hierarchy from Geosaurus

reference date

date type

creation

effective date

1979

code identifying the extent

WORLD [id=100000]

Temporal reference

Temporal extent

Begin position

1868

End position

Dataset reference date

date type

creation

effective date

1868

Frequency of update

weekly

Quality and validity

Lineage

The aa indices are derived using data from two nearly antipodal observatories, where magnetograms were available since 1868. For each three hour interval, K indices are measured at the two stations and converted back into amplitude; an individual aa index is the average of the northern and southern values, weighted to account for the small difference in latitude of the two stations, or for the slight changes in the very place of the observatory. The definitive values are published by the International Service for Geomagnetic Indices.

Conformity

Conformity report

specification

title

INSPIRE Implementing rules laying down technical arrangements for the interoperability and harmonisation of Geology

reference date

date type

publication

effective date

2011

degree

false

explanation

See the referenced specification

Conformity report

specification

title

Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services

reference date

date type

publication

effective date

2010-12-08

degree

false

explanation

See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:323:0011:0102:EN:PDF

Data format

name of format

DELIMITED ASCII - ASCII Year Files or user defined.

version of format

Constraints related to access and use

Constraint set

Limitations on public access

Constraint set

Limitations on public access

The copyright of materials derived from the British Geological Survey's work is vested in the Natural Environment Research Council [NERC]. No part of this work may be reproduced or transmitted in any form or by any means, or stored in a retrieval system of any nature, without the prior permission of the copyright holder, via the BGS Intellectual Property Rights Manager. Use by customers of information provided by the BGS, is at the customer's own risk. In view of the disparate sources of information at BGS's disposal, including such material donated to BGS, that BGS accepts in good faith as being accurate, the Natural Environment Research Council (NERC) gives no warranty, expressed or implied, as to the quality or accuracy of the information supplied, or to the information's suitability for any use. NERC/BGS accepts no liability whatever in respect of loss, damage, injury or other occurence however caused.

Responsible organisations

Responsible party

organisation name

British Geological Survey

full postal address

The Lyell Centre, Research Avenue South

EDINBURGH

EH14 4AP

United Kingdom

telephone number

0115 936 3142

facsimile number

0115 936 3276

email address

enquiries@bgs.ac.uk

responsible party role

distributor

Responsible party

organisation name

British Geological Survey

full postal address

The Lyell Centre, Research Avenue South

EDINBURGH

EH14 4AP

United Kingdom

telephone number

0115 936 3142

facsimile number

0115 936 3276

email address

enquiries@bgs.ac.uk

responsible party role

originator

Responsible party

organisation name

British Geological Survey

full postal address

The Lyell Centre, Research Avenue South

EDINBURGH

EH14 4AP

United Kingdom

telephone number

0115 936 3142

facsimile number

0115 936 3276

email address

enquiries@bgs.ac.uk

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact

organisation name

British Geological Survey

full postal address

The Lyell Centre, Research Avenue South

EDINBURGH

EH14 4AP

United Kingdom

telephone number

+44 131 667 1000

email address

enquiries@bgs.ac.uk

responsible party role

pointOfContact

Metadata date

2020-08-04

Metadata language

eng