CLIMAT

CLIMAT
Name	CLIMAT
Type	Meteorological data code
Introduced	1960s
Developer	World Meteorological Organization
Domain	Climate observation

CLIMAT

CLIMAT is an international meteorological code for monthly climate summaries used by meteorological services, research centers, and international organizations to report long-term climate observations. It serves as a standardized exchange format connecting national services, regional networks, and global systems such as the World Meteorological Organization, the Intergovernmental Panel on Climate Change, the Global Climate Observing System, and the European Centre for Medium-Range Weather Forecasts. The code enables interoperability between agencies like the Met Office, NOAA, Copernicus, Météo-France, and the Japan Meteorological Agency while supporting databases managed by institutions such as the National Centers for Environmental Information, the Hadley Centre, and the Institute of Atmospheric Physics.

Overview

CLIMAT provides a concise monthly summary for surface climate variables, facilitating reporting between national meteorological services like Deutscher Wetterdienst, Servicio Meteorológico Nacional (Argentina), Bureau of Meteorology (Australia), and regional bodies such as the European Climate Assessment & Dataset and the Asian Meteorological Service. It complements synoptic codes used by International Civil Aviation Organization stakeholders, agricultural services like Food and Agriculture Organization, and scientific programs including World Climate Research Programme and Global Energy and Water Exchanges. The format supports downstream analysis by research groups at the Lamont–Doherty Earth Observatory, Scripps Institution of Oceanography, and Potsdam Institute for Climate Impact Research.

History and Development

CLIMAT evolved from earlier observational practices codified in exchanges among the International Meteorological Organization and later the World Meteorological Organization in the mid-20th century. Development involved collaboration between national services such as U.S. Weather Bureau, Royal Netherlands Meteorological Institute, and Environment and Climate Change Canada, and research centers including the Hadley Centre and Instituto Nacional de Meteorología (Spain). Standards were refined in WMO technical regulations and manuals produced by committees like the Commission for Climatology and working groups tied to programs such as Global Climate Observing System and GCOS. Upgrades to encoding and metadata conventions have paralleled advances implemented by projects like SHARE (Stations for Homogenized Analysis of Regional climatologies), International Surface Temperature Initiative, and initiatives at the European Space Agency.

Data Format and Structure

The CLIMAT message encodes monthly values for variables such as mean temperature, monthly maximum, monthly minimum, total precipitation, and indicators for missing data. Its structure uses fixed fields and coded sections akin to other WMO formats used by the Global Telecommunication System, enabling ingestion by data centers such as NOAA National Centers for Environmental Information, Met Office Hadley Centre, and ECMWF. Metadata fields identify station details maintained in repositories like the Global Historical Climatology Network, World Data Center for Meteorology, and the International Surface Pressure Databank. The code interacts with station identifiers issued by organizations such as ICAO and WMO station identifier lists, and it complements digital formats like BUFR and NetCDF used in climate modeling by groups at NCAR and IPSL.

Applications and Use in Climate Monitoring

CLIMAT is integral to national reporting for international assessments by the Intergovernmental Panel on Climate Change, the United Nations Framework Convention on Climate Change, and services that produce climate normals used by World Food Programme and International Civil Aviation Organization. Research teams at HadCRUT, NOAA Climate Diagnostics Center, Berkeley Earth, and Copernicus Climate Change Service use CLIMAT-derived monthly series to develop indices employed in studies by Met Office Hadley Centre, Potsdam Institute, and Max Planck Institute for Meteorology. Operational agencies such as Météo-France, Japan Meteorological Agency, and Servicio Meteorológico Nacional (Mexico) use CLIMAT for monitoring droughts, hydrology assessments by FAO and UNESCO, and to calibrate reanalysis efforts like ERA-Interim and ERA5. Climate researchers at Lamont–Doherty Earth Observatory, Scripps Institution of Oceanography, and Woods Hole Oceanographic Institution combine CLIMAT data with paleoclimate proxies for long-term trend analysis.

Implementation and Tools

National meteorological services implement CLIMAT through data pipelines that interface with the Global Telecommunication System, databases at National Centers for Environmental Information, and portals like the Copernicus Climate Data Store. Software libraries and tools developed by communities including R Project for Statistical Computing, Python Software Foundation, Pandas (software), and packages from European Centre for Medium-Range Weather Forecasts enable parsing and quality control. Projects such as CLIMAT-FTP migration initiatives, I-DARE, Climate Data Rescue efforts, and platforms from Global Climate Observing System and World Meteorological Organization provide converters between CLIMAT, BUFR, CSV, and NetCDF. Academic groups at University of East Anglia, Columbia University, and ETH Zurich have produced validation toolkits and homogenization algorithms conforming to protocols used by International Meteorological Organization legacy systems.

Limitations and Criticisms

Critics highlight CLIMAT's constraints: fixed-field legacy encoding limits expressive metadata compared with modern self-describing formats adopted by NASA, European Space Agency, and Copernicus. Data completeness issues arise from uneven reporting by national services such as Servicio Meteorológico Nacional (Argentina) or under-resourced agencies in parts of Africa and South America, affecting products from Hadley Centre, Berkeley Earth, and NOAA. Interoperability challenges persist between CLIMAT and binary schemas used by ECMWF and archives at National Centers for Environmental Information, complicating automated ingest for projects at Potsdam Institute and Max Planck Institute for Meteorology. Researchers at International Surface Temperature Initiative and SHARE note difficulties in metadata provenance and station history that impact homogenization efforts used in IPCC assessments and reanalysis systems like ERA5.

Category:Meteorological codes