edu.ucar.opensky::articles:23041 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T15:24:47.051420 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7x92fg1 Towards a more reliable historical reanalysis: Improvements for version 3 of the Twentieth Century Reanalysis system 2019-10-01T00:00:00Z publication https://n2t.org/ark:/85065/d7x92fg1 https://doi.org/10.1002/qj.3598 Slivinski, L. C. author Compo, G. P. author Whitaker, J. S. author Sardeshmukh, P. D. author Giese, B. S. author McColl, C. author Allan, R. author Yin, X. author Vose, R. author Titchner, H. author Kennedy, J. author Spencer, L. J. author Ashcroft, L. author Brönnimann, S. author Brunet, M. author Camuffo, D. author Cornes, R. author Cram, Thomas A. author Crouthamel, R. author Domínguez-Castro, F. author Freeman, J. E. author Gergis, J. author Hawkins, E. author Jones, P. D. author Jourdain, S. author Kaplan, A. author Kubota, H. author Blancq, F. L. author Lee, T. author Lorrey, A. author Luterbacher, J. author Maugeri, M. author Mock, C. J. author Moore, G. K. author Przybylak, R. author Pudmenzky, C. author Reason, C. author Slonosky, V. C. author Smith, C. A. author Tinz, B. author Trewin, B. author Valente, M. A. author Wang, X. L. author Wilkinson, C. author Wood, K. author Wyszyński, P. author UCAR/NCAR - Library publisher Historical reanalyses that span more than a century are needed for a wide range of studies, from understanding large-scale climate trends to diagnosing the impacts of individual historical extreme weather events. The Twentieth Century Reanalysis (20CR) Project is an effort to fill this need. It is supported by the National Oceanic and Atmospheric Administration (NOAA), the Cooperative Institute for Research in Environmental Sciences (CIRES), and the U.S. Department of Energy (DOE), and is facilitated by collaboration with the international Atmospheric Circulation Reconstructions over the Earth initiative. 20CR is the first ensemble of sub-daily global atmospheric conditions spanning over 100 years. This provides a best estimate of the weather at any given place and time as well as an estimate of its confidence and uncertainty. While extremely useful, version 2c of this dataset (20CRv2c) has several significant issues, including inaccurate estimates of confidence and a global sea level pressure bias in the mid-19th century. These and other issues can reduce its effectiveness for studies at many spatial and temporal scales. Therefore, the 20CR system underwent a series of developments to generate a significant new version of the reanalysis. The version 3 system (NOAA-CIRES-DOE 20CRv3) uses upgraded data assimilation methods including an adaptive inflation algorithm; has a newer, higher-resolution forecast model that specifies dry air mass; and assimilates a larger set of pressure observations. These changes have improved the ensemble-based estimates of confidence, removed spin-up effects in the precipitation fields, and diminished the sea-level pressure bias. Other improvements include more accurate representations of storm intensity, smaller errors, and large-scale reductions in model bias. The 20CRv3 system is comprehensively reviewed, focusing on the aspects that have ameliorated issues in 20CRv2c. Despite the many improvements, some challenges remain, including a systematic bias in tropical precipitation and time-varying biases in southern high-latitude pressure fields. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2019 Author(s). This work is licensed under a Creative Commons Attribution 4.0 International license. None eng geoscientificInformation