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Climate Reanalysis

Climate reanalysis refers to physically-based numerical frameworks that simulate the state Earth's climate through time, guided by frequent input of real-world observations (e.g., weather stations, radiosonde, satellite, and ocean buoys). Reanalysis models are invaluable tools for understanding climate variability and change, including across areas where direct observations are not available. This page provides access to common meteorological variables for the most widely used reanalysis products. Users are encouraged to learn more about reanalysis — approach, strengths, limitations, and product comparisons — from the NCAR Climate Data Guide. Additional information about reanalysis can be found at Advancing Reanalysis.

• ECMWF European Reanalysis V5 (ERA5) [0.25°x0.25°]  | Downloaded from Copernicus C3S
• The datafiles here are regridded to 0.5°x0.5° using bilinear interpolation to reduce server load and access time.
• ECMWF European Reanalysis Interim (ERAI) [0.75°x0.75°]  | Downloaded from ECMWF
• Dataset ends August 2019. Superseded by ERA5.
• NASA Modern-Era Retrospective Analysis for Research and Applications V2 (MERRA2) [0.5°x0.625°]  | Downloaded from GES DISC
• JMA Japanese Reanalysis 55-year (JRA55) [0.5625°x0.5625°]  | Downloaded from NCAR RDA
• NCEP Climate Forecast System Reanalysis (CFSR/CFSV2) [0.5°x0.5°]  | Downloaded from NCAR RDA
  • Monthly means derived from daily means of 3-hourly values. CFSR ends March 2011; CFSV2 begins April 2011.
• NCEP/NCAR Reanalysis V1 (NNR1) [2.5°x2.5°]  | Downloaded from NOAA PSL
• NOAA/CIRES/DOE 20th Century Reanalysis V3 (20CR3) [1°x1°]  | Downloaded from NOAA PSL
• ECMWF European Reanalysis of the 20th Century (ERA-20C) [1.125°x1.125°]  | Downloaded from ECMWF
• BPRC Arctic System Reanalysis Version 2 (ASR2) [15km]  | Downloaded from NCAR RDA
  • Model domain based on a polar stereographic projection with minimum latitudes ranging 27°N-41°N.

Gridded Observations

Gridded data products place point-based or spatially discontinuous observations of Earth's climate (e.g., temperature, precipitation, wind, and sea surface temperature) onto time-registered grids and fill in data gaps using methods of interpolation. As with reanalysis, gridded datasets are useful for climate study in areas that may not have direct observations, but where the intersection of surrounding input data can provide meaningful information. Climate Reanalyzer provides access to several widely used gridded datasets.

• NOAA Optimum Interpolation Sea Surface Temperature V2.1 (OISST2.1) [0.25°x0.25°]  | Downloaded from NOAA NCEI
• NOAA Extended Reconstruction Sea Surface Temperature V5 (ERSST5) [2°x2°]  | Downloaded from NOAA NCEI
• NOAA CPC Morphing Technique Global Precipitation Analysis (CMORPH) [0.25°x0.25°]  | Downloaded from NOAA NCEI
  • Monthly totals derived from daily totals. Latitudinal data coverage 60°S-60°N.

Climate Models (Historical + Future Projections)

Climate models afford physically-based simulations of energy and material flows through the atmosphere, ocean, and other parts of the earth system. The most complex of these frameworks are earth system models, where multiple systems are coupled and yield dynamic interactions. Climate and earth system models are used to investigate past, present, and future climate evolution based on changes in radiative forcing, such as from greenhouse-gas emissions. Since 1995, the international consortium Coupled Model Intercomparison Project (CMIP) has organized a common set of experiments for modeling groups to use in future climate studies. CMIP 5 and 6 multi-model ensemble mean results (near-surface temperature, precipitation, and mean sea level pressure) are available from Climate Reanalzyer for mid- and high-warming scenarios to the year 2100. Scenarios in CMIP5 are based on Representative Concentration Pathways (RCP), and in CMIP6 on Shared Socioeconomic Pathways (SSP). Further explanation on CMIP5 and 6 can be found here. The ensemble mean CMIP 5 and 6 datafiles on this page where generated from the KNMI Climate Explorer.

• CMIP5 RCP 4.5 Ensemble Average [2.5°x2.5°]  | Downloaded from KNMI Climate Explorer
• Ensemble average of 42 models (one member each).
• CMIP5 RCP 8.5 Ensemble Average [2.5°x2.5°]  | Downloaded from KNMI Climate Explorer
• Ensemble average of 39 models (one member each).
• CMIP6 SSP2-4.5 Ensemble Average [1.25°x1.25°]  | Downloaded from KNMI Climate Explorer
• CMIP6 SSP2-4.5 radiative forcing stabilizes at 4.5 W m-2 by the year 2100 (equivalent to stabilization level of CMIP5 RCP 4.5). Refer to O'Neill et al. (2016) for further description.
• Ensemble average of 13 models (one member each: AWI-CM-1-1-MR, BCC-CSM2-MR, CAMS-CSM1-0, CanESM5 p1, CanESM5 p2, CESM2, CESM2-WACCM, FGOALS-g3, MCM-UA-1-0 f2, MIROC6, MIROC-ES2L f2, MRI-ESM2-0, UKESM1-0-LL f2).
• CMIP6 SSP5-8.5 Ensemble Average [1.25°x1.25°]  | Downloaded from KNMI Climate Explorer
• CMIP6 SSP5-8.5 radiative forcing stabilizes at 8.5 W m-2 by the year 2100 (equivalent to stabilization level of CMIP5 RCP 8.5). Refer to O'Neill et al. (2016) for further description.
• Ensemble average of 13 models (one member each: AWI-CM-1-1-MR, BCC-CSM2-MR, CAMS-CSM1-0, CanESM5 p1, CanESM5 p2, CESM2, CESM2-WACCM, FGOALS-g3, MCM-UA-1-0 f2, MIROC6, MIROC-ES2L f2, MRI-ESM2-0, UKESM1-0-LL f2).

Last updated 10 December 2023