The ECMWF reanalysis project is a
meteorological reanalysis
An atmospheric reanalysis (also: meteorological reanalysis and climate reanalysis) is a meteorological and climate data assimilation project which aims to assimilate historical atmospheric observational data spanning an extended period, using a s ...
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; an ...
(ECMWF).
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; french: Année géophysique internationale) 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 when scientific ...
) and covers 45 years to 2002. 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.
A new reanalysis product ERA5 has recently been released by ECMWF as part of Copernicus Climate Change Services. This product has higher spatial resolution (31 km) and covers the period from 1979 to present. Extension up to 1950 became available in 2020.
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
A radiosonde is a battery-powered telemetry instrument carried into the atmosphere usually by a weather balloon that measures various atmospheric parameters and transmits them by radio to a ground receiver. Modern radiosondes measure or calcula ...
,
balloon
A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air. For special tasks, balloons can be filled with smoke, liquid water, granular media (e.g. sand, flour or rice), or light so ...
s,
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
,
buoy
A buoy () is a floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents.
Types
Navigational buoys
* Race course marker buoys are used for buoy racing, the most prevalent form of yac ...
es,
satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
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 process of mathematical modelling, performed on a computer, which is designed to predict the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be deter ...
at a 125 km resolution.
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 conducts scientific research 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 philosophica ...
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 C ...
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 Foundatio ...
data archives. Both require registration.
A Python web
API
An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software Interface (computing), interface, offering a service to other pieces of software. A document or standa ...
can be used to download a subset of parameters for a selected region and time period.
See also
*
NCEP/NCAR reanalysis
References
Further reading
*
*
External links
ERA5 Reanalysis ProductERA-Interim projectERA-40 projectERA-15 project
Numerical climate and weather models
Meteorological data and networks
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