SYNOP

SYNOP
Name	SYNOP
Type	Surface synoptic code
Introduced	20th century
Purpose	Meteorological surface observations
Administered by	World Meteorological Organization

SYNOP

SYNOP is an international surface synoptic observation code used to report routine weather observations from land stations worldwide. It provides standardized reports enabling interoperability among services such as the World Meteorological Organization, the National Oceanic and Atmospheric Administration, the European Centre for Medium-Range Weather Forecasts, and national meteorological institutes including Met Office (United Kingdom), Météo‑France, and the Deutscher Wetterdienst. The code underpins global datasets used by forecasting centers like the National Weather Service and research institutions such as the University Corporation for Atmospheric Research and Scripps Institution of Oceanography.

Overview

The system originated to harmonize surface observations across networks operated by bodies such as the International Meteorological Organization and later the World Meteorological Organization. It standardizes measurements from stations run by services including the Japan Meteorological Agency, the Bureau of Meteorology (Australia), and the Service météorologique du Canada. Data encoded with the system are exchanged via telecommunications networks such as the Global Telecommunication System and assimilated into models developed by centers like the European Centre for Medium-Range Weather Forecasts and the National Centers for Environmental Prediction. Historical developments involved collaborations among institutions like the Royal Netherlands Meteorological Institute, the Finnish Meteorological Institute, and the Russian Hydrometeorological Centre.

Format and Code Structure

Reports follow a strict block-and-group format established in manuals from the World Meteorological Organization and implemented by agencies such as the International Civil Aviation Organization in aviation contexts. The structure comprises coded groups indicating station identifier, date and time coordinated with Coordinated Universal Time, and synoptic elements defined by manuals used by the Met Office (United Kingdom), the National Oceanic and Atmospheric Administration, and the Deutscher Wetterdienst. Encodings align with conventions found in message handling systems like the Global Telecommunication System and are parsed by software libraries developed by projects at the European Centre for Medium-Range Weather Forecasts and universities such as Massachusetts Institute of Technology and University of Cambridge.

Observation Parameters

Parameters encoded include pressure and pressure tendency as specified by the World Meteorological Organization manuals, present and past weather types aligned with the International Cloud Atlas, cloud amount and height standards used by the International Civil Aviation Organization and agencies like Météo‑France, surface wind speed and direction following conventions from the United Kingdom Met Office, and visibility metrics consistent with guidance from the National Weather Service and the Civil Aviation Authority (United Kingdom). Additional groups record temperature and dew point in units and digit codes harmonized with practices at institutions such as the Korea Meteorological Administration, the Indian Meteorological Department, and the Finnish Meteorological Institute.

Transmission and Distribution

Encoded observations are transmitted via infrastructures such as the Global Telecommunication System and routed through national centers like the National Centers for Environmental Prediction and the European Centre for Medium-Range Weather Forecasts. Distribution pathways include data exchanges among services like the World Meteorological Organization Members, regional hubs such as the WMO Regional Association II (Asia), and international research collaborations involving organizations like the World Climate Research Programme and the Global Climate Observing System. Message handling relies on formats compatible with software from projects led by institutions such as ECMWF, the National Oceanic and Atmospheric Administration, and academic consortia at the University of Reading.

Uses in Meteorology and Aviation

Operational forecasting centers such as the European Centre for Medium-Range Weather Forecasts, the National Weather Service, and the Japan Meteorological Agency ingest these reports for data assimilation into numerical weather prediction systems like models developed at ECMWF and the National Centers for Environmental Prediction. Aviation authorities including the International Civil Aviation Organization, national regulators like the Federal Aviation Administration, and air navigation service providers utilize encoded surface observations to complement METAR reporting at airports overseen by entities such as Airservices Australia and NAV CANADA. Climatologists at institutions like the Hadley Centre and NOAA's National Climatic Data Center use historical archives of these messages for climate monitoring and research.

International Standards and Organizations

Standards and guidance are promulgated by the World Meteorological Organization in coordination with the International Civil Aviation Organization and implemented by national services including the Met Office (United Kingdom), the Deutscher Wetterdienst, and the Japan Meteorological Agency. Regional bodies such as the European Organisation for the Exploitation of Meteorological Satellites and programs like the Global Climate Observing System interface with surface observation networks that produce these coded messages. Research and operational development involve collaborations among universities and centers such as the European Centre for Medium-Range Weather Forecasts, National Oceanic and Atmospheric Administration, and the University Corporation for Atmospheric Research.

Category:Meteorological data formats