An Evaluation of the Performance of the Twentieth Century Reanalysis Version 3

Abstract The performance of a new historical reanalysis, the NOAA–CIRES–DOE Twentieth Century Reanalysis version 3 (20CRv3), is evaluated via comparisons with other reanalyses and independent observations. This dataset provides global, 3-hourly estimates atmosphere from 1806 to 2015 by assimilating only surface pressure observations prescribing sea temperature, ice concentration, radiative forcings. Comparisons observations, reanalyses, satellite products suggest that 20CRv3 can reliably produce atmospheric on scales ranging weather events long-term climatic trends. Not does recreate “best estimate” weather, including extreme events, it also an estimate its confidence through use ensemble. Surface statistics these are reliable. upper-air in Northern Hemisphere demonstrate has skill throughout twentieth century. Upper-air fields late century early twenty-first correlate well full-input correlation predicted 20CRv3. analyzed 500-hPa geopotential heights for 1979–2015 comparable modern operational 3–4-day forecasts. Finally, performs climate time scales. Long series multidecadal averages mass, circulation, precipitation agree station- satellite-based products. able capture trends tropospheric-layer temperatures century, placing recent longer context.