WORLD METEOROLOGICAL ORGANIZATION
________________

MEETING OF EXPERT TEAM ON INTEGRATED DATA MANAGEMENT

GENEVA, 17-20 SEPTEMBER 2001

ET-IDM/Doc. 3(1)
(12.VI.2001)
____

ITEM: 1.2

ENGLISH ONLY

 

Proposal for a Discovery-level WMO Metadata Standard

Submitted by the Secretariat

Summary and Purpose of Document

The following straw-man proposal, based on the Global Change Master Directory DIF (Directory Interchange Format), the WMO BUFR code tables and the emerging ISO metadata standard defines basic descriptive or directory-level metadata that should be made available and searchable.

 

ACTION PROPOSED

The meeting is requested to consider the proposal and provide suggestions for further development and follow-up actions.

Discussion

The wide range of data and products that could be of potential use to the various WMO programmes creates a need for extensive metadata to describe them. Furthermore, to facilitate identification and location of this information across a number of programmes, basic descriptive or directory-level metadata should be made available and searchable according to an agreed standard. It is important that the extent of this directory-level information be detailed enough to provide critical information but simple enough to be easily collected and maintained. The following proposal, based on the Global Change Master Directory DIF (Directory Interchange Format), the WMO BUFR code tables, and the draft ISO metadata standard attempts to provide the appropriate balance.

All of the fields below would be required. The proposed standard would provide a definition for directory searches and would not specify how the information should be archived or presented to users.

Field

Field contents

 Field definition

Abstract

Character string

 Brief narrative summary of the contents of the dataset

MD_Keywords

Character string

 Keywords, their type and reference source (WMO)

Language

Code, ISO 639

 Language of the description

StartDate

Date, ISO 19108

 Beginning or actual date of the data

StartTime

Time, UTC

Beginning time of the data (UTC)

StopDate

Date, ISO 19108

 Ending date of the data (blank if not applicable)

StopTime

Time, UTC

 Ending time of the data (blank if not applicable)

ReferenceDate

Date, ISO 19108

 Reference date of the dataset (blank if not applicable)

ReferenceTime

Time, UTC

 Reference time of the dataset (blank if not applicable)

Geographic
Box

Angle (-180 to 180)

Angle

Angle

Angle

 WestBoundLongitude

EastBoundLongitude

NorthBoundLatitude

SouthBoundLatitude
Geographic
Description:

CharacterString

Geographic Identifiers (ISO 19112)

MD_Category

Code

 Numeric code for the discipline covered by this dataset
See ISO standard below

Theme

Code

 The theme or subject of the dataset would be specified from a list of standard themes defined for each category. A very rough first draft is given below.

 

MD_Category
Name Code Definition
Agriculture / Farming 001 Agriculture, herding, irrigation, plantations
Climatology / Meteorology / Atmosphere 005 Processes and phenomena of the atmosphere (cloud cover, precipitation, temperature); changes in climate
Elevation and derived products 008 Altitude (elevation, height above or below sea level)
Geoscientific information 010 geography (topography, toponomy); geomorphology; general geology; economic geology; geophysics; soils; geochemistry; permafrost; geological processes; palaeontology; risks of earthquakes, volcanoes, sinkholes, landslides, avalanches
Imagery / Base maps / Earth cover 012 remotely sensed information such as ground cover e.g. scans of the earth by satellite, aerial photographs and imagery; topographic maps, aeronautical, topocadastral maps, hydrographic charts; land use (land cover, public lands, land tenure, urban and regional land use plans)
Inland waters 014 rivers, lakes, glaciers, continental ice sheets, snow; ground water; water utilisation plans; movement of water in relation to land; floods; dams; pans; vleis; swamps; reservoirs; marshes; drainage regions; swimming pools
Oceans 017 Salt water bodies and their features; bathymetry, tides, currents, waves, nautical aides

 

Dataset Themes (Subsets of Categories)

Agriculture (001)

Agricultural sciences
Agricultural chemistry
Crop yield/forecasts
Forestry
Soils

Climate / Meteorology / Atmosphere (005)

Aerosols
Air quality
Altitude
Atmospheric chemistry
Atmospheric phenomena
Climatology/normals
Clouds
Events/extremes
Forecasts
Model analyses
Precipitation
Radiance/imagery
Radiological
Snow cover/depth
Surface land
Surface marine
Soundings/upper air
Temperature
Water Vapour
Wind

Elevation and derived products (008)

Topography/elevation

 Geoscientific information (010)

Ice core records
Land records
Ocean/lake records
Tree ring records

Imagery / Base maps / Earth cover (012)

Erosion/sedimentation
Land use/cover
Landscape
Soils
Soil temperature
Surface radiative properties

Inland waters (014)

Surface water
Water quality
Snow/ice
Glacial depth/volume
Sea ice
Ground water

Oceans (016)

Bathymetry
Marine geophysics
Marine sediments
Ocean acoustics
Ocean chemistry
Ocean circulation
Ocean heat budget
Ocean optics
Ocean temperature
Salinity/density
Sea ice
Sea surface height
Tides

 

Sample Entry in a Metadata File

The sample provides an example of a dataset description conforming to the proposed guidelines. However, The ISO standard defines the content of a set of metadata elements, their definitions, data types, and inherent dependencies. The logical model of the metadata specifies the content and not the form of implementation or the form of presentation. A primary goal in the management of geographic metadata is the ability to access the metadata and the related spatial data it describes. This requires software implementations using common encoding methods to achieve operational use of the geographic metadata. Annex I to the ISO standard provides an overview of methods for the encoding of metadata element structure and content for the purposes of search and retrieval, metadata exchange, and presentation.

The example below includes item tags and indentation to aid interpretation but does not represent a recommended presentation. Instead the metadata should be presented encoded in Standard Generalised Markup Language (SGML), eXtensible Markup Language (XML) or in another agreed presentation format.

hierarchyLevel: dataset

identificationInfo

MD_Identification

language: en

characterSet: ISO 10646-2

abstract: NCAR provides European Center for Medium Range Weather Forecasting FGGE global analysis data. This is a gridded analysis of data on a horizontal surface. Grid coverage includes the entire globe (uniform and complete latitude/longitude grid, 96x25, 3.75-degr, northern hemsiphere and southernhemisphere are separate, derived from 192x49 1.875-degr).

MD_Keywords:

keyword: grid, analysis, global, surface,1000mb, 850mb, 700mb, 500mb, 400mb, 300mb, 200mb, 150mb, 100mb, 50mb, 30mb, 20mb, 10mb
type: 001 (vertical/spatial)
thesaurusName: WMO
keyword: {appropriate GRIB parameter codes, 001, 006, 011, 017, etc}
type: 002 (GRIB parameters)
thesaurusName: WMO

geographicBox:

westBoundLongitude: -180.0
eastBoundLongitude: 180.0
northBoundLatitude: 90.0
southBoundLatitude: -90.0

geographicDescription

SI_LocationInstance

geographicIdentifier: Globe

EX_TemporalExtent

startDate: 19781201
startTime: 0000
stopDate: 19791130
stopTime: 2359

MD_Category: 005

Theme: Model analyses, Temperature, Water Vapour, Wind

CI_Citation

title: ECMWF FGGE global analysis
date: 19970801
dateType: publication date
edition: 1

datasetPointOfContact:

CI_ResponsibleParty

organisationName: NCAR Data Support Section

CI_Telephone

voice: 1-(303) 497-1219
facimile: 1-303-497-1298

CI_Address

deliveryPoint: NCAR/SCD/Data Support Section, P.O. Box 3000
city: Boulder
administrativeArea: CO
postalCode: 80307
country: USA
electronicMailAddress: datahelp@ncar.ucar.edu

CI_OnlineResource

linkage: http://www.scd.ucar.edu/dss/datasets/ds307.5.html