Observations - Data - Modelling

Observations - Data - Modelling


Local weather forecasts depend on real time access to observations from around the globe. Observations are key to our understanding of how the Earth system – the atmosphere, oceans, freshwater bodies, land and the biosphere – shapes our weather, climate and hydrology. 

Currently, well over 10 000 manned and automatic surface weather stations, 1 000 upper-air stations, 7 000 ships, 100 moored and 1 000 drifting buoys, hundreds of weather radars and 3 000 specially equipped commercial aircraft measure key parameters of the atmosphere, land and ocean surface every day. Add to these some 30 meteorological and 200 research satellites to get an idea of the size of the global network for meteorological, hydrological and other geophysical observations. Once collected, observations are quality-controlled, based on technical standards defined by the WMO Instruments and Methods of Observation Programme (IMOP), then made freely available to every country in the world through the WMO Information System (WIS).

WMO facilitated the establishment, maintenance and continuing expansion of this global network, the activities of which are coordinated within the Global Observing System (GOS) of the WMO World Weather Watch (WWW). The WMO co-sponsored Global Climate Observing System (GCOS) and Global Ocean Observing System (GOOS) also play a major role in improving the collection of required data for the development of climate forecasts and climate change detection.

The WMO Integrated Global Observing System (WIGOS) acts as its umbrella for these networks, using the WMO Information System (WIS) to connect together all regions for data exchange, management and processing.

Data exchange and technology transfer

Powerful computers in WMO centres worldwide process the data collected from tens of thousands of land and sea observation instruments and Earth-observing satellites. These data are used in numerical models based on physical laws to produce weather, climate and water-related forecasts, predictions, and information products and services for use in daily lives, long-term decision-making and research.

WMO Unified Data Policy Resolution (Res.1)

The free and unrestricted exchange of observational data from all parts of the world and of other data products among all WMO Members must be updated and strengthened to accommodate the explosive growth in the demand for weather, climate, and water monitoring and prediction data to support essential services needed by all sectors of society, as they face issues such as climate change, increasing frequency and impact of extreme weather, and implications for food security.

Aircraft-Based Observations

Aircraft-based observations, comprised of reports of meteorological data and information provided or transmitted from an aircraft platform, have made a significant contribution to upper-air monitoring of the atmosphere since the early twentieth century. Initially, this contribution was limited to PIlot REPorts (PIREP), consisting of little more than radio communications from pilots back to the ground regarding weather phenomena and conditions encountered during flight.

Data rescue and archives

Data repositories and archives play a critical role as the source for the observational data used in the study of weather and climate. After over two centuries of recording observations on physical media – and the last 20 years on digital media – these records are at risk.

Centennial Observing Stations

Long-term meteorological observations are part of the irreplaceable cultural and scientific heritage of mankind that serve the needs of current and future generations for long-term high quality climate records. They are unique sources of past information about atmospheric parameters, thus are references for climate variability and change assessments. To highlight this importance, WMO has a mechanism to recognize centennial observing stations.

Frequently Asked Questions: Observations