The ECMWF reanalysis project is a
meteorological reanalysis project carried out by the
European Centre for Medium-Range Weather Forecasts
The European Centre for Medium-Range Weather Forecasts (ECMWF) is an independent intergovernmental organisation supported by most of the nations of Europe. It is based at three sites: Shinfield Park, Reading, United Kingdom; Bologna, Italy; a ...
(ECMWF), integrating historical meteorological observations onto a regularly spaced global grid for retrospective weather
data analysis
Data analysis is the process of inspecting, Data cleansing, cleansing, Data transformation, transforming, and Data modeling, modeling data with the goal of discovering useful information, informing conclusions, and supporting decision-making. Da ...
.
The first reanalysis product, ERA-15, generated reanalyses for approximately 15 years, from December 1978 to February 1994. The second product, ERA-40 (originally intended as a 40-year reanalysis) begins in 1957 (the
International Geophysical Year
The International Geophysical Year (IGY; ), also referred to as the third International Polar Year, was an international scientific project that lasted from 1 July 1957 to 31 December 1958. It marked the end of a long period during the Cold War w ...
) and covers 45 years to 2002 at a resolution of 125 km. As a precursor to a revised extended reanalysis product to replace ERA-40, ECMWF released ERA-Interim, which covers the period from 1979 to 2019.
The reanalysis product ERA5, released by ECMWF as part of the
Copernicus Climate Change Service
The Copernicus Climate Change Service (abbreviated as C3S) is one of the six thematic services provided by the European Union's Copernicus Programme. The Copernicus Programme is managed by the European Commission and the C3S is implemented by th ...
, features a spatial resolution of 31 km and currently spans from 1940 to the present. It has since become one of the most widely used global historical weather datasets in scientific research.
A new update, ERA6, is in development with ~14 km horizontal resolution, and is planned for staged release beginning with the most recent 20 years by late 2026.
In addition to reanalysing all the old data using a consistent system, the reanalyses also make use of much archived data that was not available to the original analyses. This allows for the correction of many historical hand-drawn maps where the estimation of features was common in areas of data sparsity. The ability is also present to create new maps of atmosphere levels that were not commonly used until more recent times.
Generation
Many sources of the meteorological observations were used, including
radiosondes,
balloon
A balloon is a flexible membrane bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, or air. For special purposes, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), ...
s,
aircraft
An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...
,
buoy
A buoy (; ) is a buoyancy, floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents.
History
The ultimate origin of buoys is unknown, but by 1295 a seaman's manual referred to navig ...
es,
satellite
A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...
s,
scatterometer
A scatterometer or diffusionmeter is a scientific instrument to measure the return of a beam of light or radar waves scattered by diffusion in a medium such as air. Diffusionmeters using visible light are found in airports or along roads to measur ...
s. This data was run through the ECMWF
computer model
Computer simulation is the running of a mathematical model on a computer, the model being designed to represent the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be determin ...
.
As the ECMWF's computer model is one of the more highly regarded in the field of forecasting, many
scientists
A scientist is a person who researches to advance knowledge in an area of the natural sciences.
In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosophical study of nature ...
take its reanalysis to have similar merit. The data is stored in
GRIB
GRIB (GRIdded Binary or General Regularly-distributed Information in Binary form) is a concise data format commonly used in meteorology to store historical and forecast weather data. It is standardized by the World Meteorological Organization's ...
format. The reanalysis was done in an effort to improve the accuracy of historical weather maps and aid in a more detailed analysis of various weather systems through a period that was severely lacking in computerized data. With the data from reanalyses such as this, many of the more modern computerized tools for analyzing storm systems can be utilized, at least in part, because of this access to a computerized simulation of the atmospheric state.
Accessing the data
The ECMWF re-analysis products are accessible from the Climate Change Services homepage.
The data can be downloaded for research use from ECMWF's homepage (see external links) and the
National Center for Atmospheric Research
The US National Center for Atmospheric Research (NCAR ) is a US federally funded research and development center (FFRDC) managed by the nonprofit University Corporation for Atmospheric Research (UCAR) and funded by the National Science Foundat ...
data archives. Both require registration.
A Python web
API
An application programming interface (API) is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build ...
can be used to download a subset of parameters for a selected region and time period.
See also
*
NCEP/NCAR reanalysis
References
Further reading
*
* -2020 research where ERA5 data was used.
* -2023 research where ERA5 data was used.
External links
ERA5 Reanalysis ProductERA-Interim projectERA-40 projectERA-15 project
ECWMF numerical models
Meteorological data and networks
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