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WMO Regions and Subregions (GRDC, 2004)

Hydrological Subregions of the World Hydrological Subregions of the WorldHydrological Subregions of the World (click to enlarge)

The meteorological and related activities within WMO are coordinated by the WMO Regional Associations (RAs), composed of the WMO-Members from the respective regions of the world. The current status of the RAs is published quarterly in WMO Publication No. 5: Composition of WMO. The geographical limits of the regions are shown in the (electronic) edition of the WMO Publication No. 15: Basic Documents, No 1 - Convention, General Regulations, Staff Regulations, Financial Regulations and Agreements.

WMO Subregions had been defined by WMO according to the six WMO Regions. Within each WMO Region at maximum 99 subregions had been defined, most of them representing a sea-outlet drainage basin or one of its back-to-back parts, irrespective of the basin size. Sometimes the basin of a tributary to a major river constitutes a subregion of its own, e.g. the Negro River Basin as part of the Amazon River Basin. However, the partition of large drainage basins seems to be guided rather by geographical than hydrological lines. The remaining areas between the sea-outlet basins were summarized into separate coastal subregions. Thus, the WMO Subregions represent catchments or subchatchments as well as countries, geographical regions, coastal sections or islands.

GRDC presents here the WMO Subregions derived from the basin indicators as listed per WMO Region in the Manual on Codes - Volume II: Regional Codes and National Coding Practices (WMO-No 306). Associated GIS layers of the WMO Subregions were compiled on the basis of the DEM Hydro1k (some with manual corrections), the Major River Basins of the World derived and adjusted by the GRDC, and the country-shape file provided by ESRI within ArcGIS. In some cases, when subregions could not be displayed explicitly, these were combined.

Maps and tabular summaries of WMO subregions:

Hydrologic subregions in WMO region 1: Africa

Hydrologic subregions in WMO region 2: Asia

Hydrologic subregions in the WMO region 3: South America

Hydrologic subregions in the WMO region 4: North, Central America and Caribbean

Hydrologic subregions in the WMO region 5: South-West Pacific

Hydrologic subregions in the WMO region 6: Europe

GRDC provides the GIS layers of the WMO Subregions under the conditions of the GRDC data policy. If you are interested to use one of these GIS layers for your research, please sign the user declaration and send it to GRDC together with a brief description of the project for which the layers will be used. Please fill in the order form including your contact details.

Please cite the files in all publications and products using them as: Global Runoff Data Centre (2004): WMO Subregion / Global Runoff Data Centre. Koblenz, Germany: Federal Institute of Hydrology (BfG), 2004..

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