Meteorological reanalysis

A meteorological reanalysis is a meteorological data assimilation project which aims to assimilate historical observational data spanning an extended period, using a single consistent assimilation (or "analysis") scheme throughout.


Operational data analysis

In operational numerical weather prediction, forecast models are used to predict future states of the atmosphere, based on how the climate system evolves with time from an initial state. The initial state provided as input to the forecast must consist of data values for a range of "prognostic" meteorological fields – that is, those fields which determine the future evolution of the model. Spatially varying fields are required in the form used by the model, for example at each intersection point on a regular grid of longitude and latitude circles, and initial data must be valid at a single time that corresponds to the present or the recent past. By contrast, the available observational data usually do not include all of the model's prognostic fields, and may include other additional fields; these data also have different spatial distribution from the forecast model grid, are valid over a range of times rather than a single time, and are also subject to observational error. The technique of data assimilation is therefore used to produce an analysis of the initial state, which is a best fit of the numerical model to the available data, taking into account the errors in the model and the data.

The need for reanalysis

In addition to being used for initializing the operational forecasts, the analyses themselves are a valuable tool for subsequent meteorological and climatological studies. However, an operational analysis dataset, i.e. the analysis data which were used for the real-time forecasts, will typically suffer from inconsistency if it spans any extended period of time, because operational analysis systems are frequently being improved. A reanalysis project involves reprocessing observational data spanning an extended historical period using a consistent modern analysis system, to produce a dataset that can be used for meteorological and climatological studies.

Examples of reanalysis datasets include the ECMWF re-analysis[1] and the NCEP/NCAR Reanalysis[2] (N.B. these linked articles include published references), and the JRA-25[3] reanalysis from the Japan Meteorological Agency.

Caution in usage

While often reanalysis can be thought as the best estimate on many variables (such as winds and temperature) of the atmosphere, its usage must be taken with caution. Degradation of, replacement of, or changes to instruments (e.g. satellites), and changes in methods of observation (e.g., surface, aloft), may inject error.[4] Not all reanalysis data are constrained by observation: some data types, such as precipitation (depending on the reanalysis) and surface evapotranspiration (for which global observations simply do not exist), are obtained by running (presumably newer) general circulation or NWP models. Reanalyses are known not to conserve moisture.[5]


  1. ^ Uppala, S., and coauthors, 2005: The ERA-40 Re-Analysis. Quart. J. Roy. Meteor. Soc., 131, 2961-3012.
  2. ^ Kalnay, E., and coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437-471.
  3. ^ Onogi, K., and coauthors, 2007: The JRA-25 Reanalysis. J. Meteor. Soc. Japan, 85, 369-432.
  4. ^ Trenberth, K. E., D. P. Stepaniak, J. W. Hurrell, and M. Fiorino, 2001: Quality of Reanalyses in the Tropics. J. Climate, 14, 1499-1510.
  5. ^ Nigam, S., and A. Ruiz-Barradas, 2006: Seasonal Hydroclimate Variability over North America in Global and Regional Reanalyses and AMIP Simulations: Varied Representation. J. Climate, 19, 815-837.

Reading about specific reanalyses

  • Kalnay, E., and coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437-471.
  • Kanamitsu, M., W. Ebisuzaki, J. Woolen, S.-K. Yang, J. J. Hnilo, M. Fiorino, and G. L. Potter, 2002: NCEP-DOE AMIP-II Reanalysis (R-2). Bull. Amer. Meteor. Soc., 83, 1631-1643.
  • Mesinger, F., and coauthors, 2006: North American Regional Reanalysis. Bull. Amer. Meteor. Soc., 87, 343-360.
  • Uppala, S., and coauthors, 2005: The ERA-40 Re-Analysis. Quart. J. Roy. Meteor. Soc., 131, 2961-3012.
  • Onogi, K., and coauthors, 2007: The JRA-25 Reanalysis. J. Meteor. Soc. Japan, 85, 369-432.

External links

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Meteorological history of Hurricane Andrew — Hurricane Andrew Category 5 hurricane (SSHS) The path of Hurricane Andrew Formed August 16, 1992 Dissipated …   Wikipedia

  • Atlantic hurricane reanalysis — is an ongoing project within the National Oceanic and Atmospheric Administration which seeks to correct and add new information about past Atlantic tropical cyclones. It was started around 2000 to update HURDAT, the official hurricane database… …   Wikipedia

  • Automated Quality control of meteorological observations — A meteorological observation at a given place can be inaccurate for a variety of reasons, such as a hardware defect. Quality control can help spot which meteorological observations are inaccurate.One of the main automated quality control program… …   Wikipedia

  • Masao Kanamitsu — (November 6, 1943 in Kumamoto, Japan August 17, 2011 in Del Mar, California) was Japanese and American atmospheric scientist working in the field of data assimilation. His research greatly influenced global and regional climate change studies… …   Wikipedia

  • Tornado — This article is about the weather phenomenon. For other uses, see Tornado (disambiguation). For the current tornado season, see Tornadoes of 2011 …   Wikipedia

  • Christopher Landsea — Nationality United States of America Education Ph.D. in Atmospheric Science Alma mater Colorado State University …   Wikipedia

  • Jagdish Shukla — Jagdish Shukla(born 1944) is an Indian meteorologist and Distinguished University Professor at George Mason University in the United States.Early yearsDr. Shukla was born in 1944 in a small village (Mirdha) in the Ballia district of Uttar Pradesh …   Wikipedia

  • Tornado records — This is a list of some tornado records. Tornado outbreaks Most tornadoes in single outbreak The Super Outbreak of April 3 4, 1974 spawned 148 confirmed tornadoes across eastern North America and resulted in the second highest death toll (319) in… …   Wikipedia

  • Climate of the Arctic — The climate of the Arctic is characterized by long, cold winters and short, cool summers. There is a large amount of variability in climate across the Arctic, but all regions experience extremes of solar radiation in both summer and winter. Some… …   Wikipedia

  • Hurricane Andrew — This article is about the 1992 hurricane. For the 1986 tropical storm, see Tropical Storm Andrew (1986). Hurricane Andrew Category 5 Hurricane (SSHS) Hurricane Andrew approaching the Bahamas and Florida as a Category 5 hurricane Formed …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.