About the Conference

The 4th WCRP International Conference on Reanalyses (ICR4) provides an opportunity for the global community to review and discuss the major observations and modeling research associated with reanalyses, including the current uncertainties, such as consistency of the time series, and the complexity of Earth system.

Characterizing the uncertainty and quality of reanalyses is a task that reaches far beyond the international community of developing institutions, and into the interdisciplinary research community, especially those using the reanalyses products in their research and applications.


Atmospheric, oceanic and land retrospective analyses, or “reanalyses,” have become fundamental tools for weather, ocean, hydrology and climate research. They continue to evolve from improvements in data assimilation, numerical modeling, and observation recovery and quality control, and have become ultimately long-term climate and environmental records. Reanalyses are natural integrative tools, yet coupling the components of the Earth system in reanalyses remains a great challenge.

Observations are the key resource in producing reanalyses and improvements in algorithms and quality control are still advancing. Additional challenges remain to account for model bias as new data are assimilated and the observation record evolves (e.g., new instruments replace old). These issues are especially important for using reanalyses in climate research. Extending the reanalysis record back in time is a fundamental need of the weather and climate research community. Considering these challenges, we plan to convene the 4th WCRP International Conference on Reanalyses with the objectives of:

  1. Sharing understanding of the major challenges facing reanalyses: the changing observing system and Integrated Earth system.

  2. Assessing the state of the disciplinary atmospheric, ocean and land reanalyses, including the needs of the research community for weather, ocean, hydrology and climate reanalyses.

  3. Reviewing the new developments in the reanalyses, models and observations for study of the Earth System.

  4. Exploring international collaboration in reanalyses including its role in regional and global climate services.

Expected Outcomes:

reanalyses logoFor information about reanalyses, see reanalyses.org

The goal of reanalyses.org is to facilitate comparison between reanalysis and observational data sets. Evaluative content provided by reanalysis developers, observationalists, and users; and links to detailed data descriptions, data access methods, analysis and plotting tools, and data set references are available.

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