Data access

APIs

In addition to raw data access mechanisms, the WOUDC archive is also available using Web Application Programming Interfaces (APIs) and geospatial web services adhering to publically available international standards. Web APIs are designed to support machine to machine interaction over the Internet, and can be used in web, mobile or desktop applications and tools.

WOUDC APIs support open standards from the Open Geospatial Consortium (OGC) , which facilitate interoperability and thus make ozone and UV data easy to discover, access, visualize and integrate. OGC standards play an important role in lowering the barrier to weather/climate/water data exchange as part of the WMO Information System and are supported by numerous off the shelf open source and commercial tools.

The WOUDC API is available at https://api.woudc.org . The API provides discovery, access, visualization and processing functionality to all WOUDC data and metadata, as well as processes for data validation, reporting and quality assessment.

For developers, a Swagger interface is available at https://api.woudc.org/openapi .

The WOUDC API is powered by pygeoapi , a reference implementation of OGC API standards.

WMO Information System

The WMO Information System 2.0 (WIS2) is the framework for WMO data sharing in the 21st century for all WMO domains and disciplines. It supports the WMO Unified Data Policy, the Global Basic Observing Network (GBON) and makes international, regional, and national data sharing simple, effective, and inexpensive. The idea that no Member should be left behind and the objective of lowering the barrier to adoption has been at the core of WIS 2.0 development. These objectives inspire the principles underpinning the WIS 2.0 technical framework, such as adopting open standards and Web technologies to facilitate sharing of increasing variety and volume of real-time data.

WIS2 has been in operation since January 2025 and replaces the Global Telecommunication System (GTS).

WIS2 manuals and guides can be found at the following locations:

• Manual on the WMO Information System, Volume II - WMO Information System 2.0
• Guide to the WMO Information System Volume II - WMO Information System 2.0
• Provisions for the transition from the WMO Information System (WIS) 1.0 and Global Telecommunication System to WIS 2.0
• WMO unified data policy for the international exchange of earth system data (Resolution 1 (Cg-Ext(2021))

For informative purposes, the WIS2 Cookbook provides numerous examples, code snippets, recipes and workflows in support of WIS2 requirements.

WOUDC data is shared on WIS2 and can be discovered, accessed and retrieved as per the WMO WIS2 Technical Regulations.

      ---
      title: WIS2 discovery, subscription and download
      ---
      flowchart TD
          accTitle: WIS2 discovery, subscription and download
          accDescr {
            A flowchart demonstrating the cycle between (1) the Data Consumer searching the WIS2 Global Discovery Catalogue, (2) which then subscribes to the WIS2 Global Broker, (3) which then notifies the Data Consumer.
            In addition, (4) the Data Consumer can download from the WIS2 Global Cache
          }
          A[fa:fa-user Data Consumer] -->|1 - search| B[fa:fa-book WIS2 Global Discovery Catalogue]
          B -->|2 - subscribe| C[fa:fa-bullhorn WIS2 Global Broker]
          C -->|3 - notify| A
          A -->|4 - download| D[fa:fa-download WIS2 Global Cache]
    

The WIS2 GDC is available at https://wis2-gdc.weather.gc.ca/collections/wis2-discovery-metadata . This catalogue provides discovery services for all data on WIS2.

To discover WOUDC data on WIS2, a user may query the GDC as follows:

• Spatial query (all data over Canada)
• Keyword search:
• All datasets with 'Canada'
• All datasets from WOUDC
• Total ozone Brewer observations data

Note that the WIS2 GDC provides search results in HTML or JSON. JSON results are made available by adding f=json to search queries.

The WIS2 GDC search results provide access links (raw data download, API, notifications). For access to real-time data, a user can connect and subscribe to one of the WIS2 Global Brokers specified in the search results, via the MQTT protocol.