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Title: The KLIWAS North Sea Climatology. Part II: Assessment against Global Reanalyses

Abstract

Observational reference datasets are needed in atmosphere and ocean for quality assessments of climate models and for the evaluation of atmospheric reanalyses. To meet this demand on the regional scale, the Climate Water Navigation (KLIWAS) North Sea climatology (KNSC) was developed. This paper uses KNSC to assess the quality of five atmospheric reanalysis products [ERA-40; ERA-Interim; NCEP-1; 20CR, version 2 (20CRv2); and MERRA] over the North Sea from 1979 to 2001. Differences in sea level pressure (2-m air temperature) can be found in coastal regions for ERA-40/ERA-Interim and MERRA, and are more pronounced during positive (negative) phases of the NAO. 20CRv2 shows biases over the entire North Sea and all seasons of several hectopascals. ERA-40 and ERA-Interim show a negative 2-m air temperature bias relative to KNSC along the coastal mainland of Europe, especially during winter months, possibly a result of a remaining land influence. Mean differences result from winter and fall, mostly remaining within measurement uncertainties. Despite the upgrades in the model setup, ERA-Interim shows negligible differences from ERA-40. 20CRv2 and MERRA show positive (negative) biases during the summer (winter) half year. NCEP-1 follows ERA-40/ERA-Interim but mostly with slightly higher differences. All five reanalyses reproduce the decadal variability andmore » climate shift signals present in KNSC fields. Overall, only 20CRv2 has to be considered as clearly unsatisfactorily regarding biases, MAE, and RMSE compared to all other datasets investigated. This study suggests that similar intercomparison studies, performed over other parts of the world’s oceans, especially coastal regions, can be very helpful in identifying shortcomings in atmospheric reanalysis products.« less

Authors:
 [1];  [2];  [2];  [2];  [3];  [3];  [2]
  1. Federal Maritime and Hydrographic Agency (BSH), and Centrum für Erdsystemforschung und Nachhaltigkeit, Universität Hamburg, Hamburg, Germany
  2. Centrum für Erdsystemforschung und Nachhaltigkeit, Universität Hamburg, Hamburg, Germany
  3. Deutscher Wetterdienst (DWD), Hamburg, Germany
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1565705
Resource Type:
Journal Article
Journal Name:
Journal of Atmospheric and Oceanic Technology
Additional Journal Information:
Journal Volume: 35; Journal Issue: 1; Journal ID: ISSN 0739-0572
Publisher:
American Meteorological Society
Country of Publication:
United States
Language:
English
Subject:
Engineering; Meteorology & Atmospheric Sciences

Citation Formats

Schade, Nils H., Sadikni, Remon, Jahnke-Bornemann, Annika, Hinrichs, Iris, Gates, Lydia, Tinz, Birger, and Stammer, Detlef. The KLIWAS North Sea Climatology. Part II: Assessment against Global Reanalyses. United States: N. p., 2018. Web. doi:10.1175/jtech-d-17-0045.1.
Schade, Nils H., Sadikni, Remon, Jahnke-Bornemann, Annika, Hinrichs, Iris, Gates, Lydia, Tinz, Birger, & Stammer, Detlef. The KLIWAS North Sea Climatology. Part II: Assessment against Global Reanalyses. United States. https://doi.org/10.1175/jtech-d-17-0045.1
Schade, Nils H., Sadikni, Remon, Jahnke-Bornemann, Annika, Hinrichs, Iris, Gates, Lydia, Tinz, Birger, and Stammer, Detlef. 2018. "The KLIWAS North Sea Climatology. Part II: Assessment against Global Reanalyses". United States. https://doi.org/10.1175/jtech-d-17-0045.1.
@article{osti_1565705,
title = {The KLIWAS North Sea Climatology. Part II: Assessment against Global Reanalyses},
author = {Schade, Nils H. and Sadikni, Remon and Jahnke-Bornemann, Annika and Hinrichs, Iris and Gates, Lydia and Tinz, Birger and Stammer, Detlef},
abstractNote = {Observational reference datasets are needed in atmosphere and ocean for quality assessments of climate models and for the evaluation of atmospheric reanalyses. To meet this demand on the regional scale, the Climate Water Navigation (KLIWAS) North Sea climatology (KNSC) was developed. This paper uses KNSC to assess the quality of five atmospheric reanalysis products [ERA-40; ERA-Interim; NCEP-1; 20CR, version 2 (20CRv2); and MERRA] over the North Sea from 1979 to 2001. Differences in sea level pressure (2-m air temperature) can be found in coastal regions for ERA-40/ERA-Interim and MERRA, and are more pronounced during positive (negative) phases of the NAO. 20CRv2 shows biases over the entire North Sea and all seasons of several hectopascals. ERA-40 and ERA-Interim show a negative 2-m air temperature bias relative to KNSC along the coastal mainland of Europe, especially during winter months, possibly a result of a remaining land influence. Mean differences result from winter and fall, mostly remaining within measurement uncertainties. Despite the upgrades in the model setup, ERA-Interim shows negligible differences from ERA-40. 20CRv2 and MERRA show positive (negative) biases during the summer (winter) half year. NCEP-1 follows ERA-40/ERA-Interim but mostly with slightly higher differences. All five reanalyses reproduce the decadal variability and climate shift signals present in KNSC fields. Overall, only 20CRv2 has to be considered as clearly unsatisfactorily regarding biases, MAE, and RMSE compared to all other datasets investigated. This study suggests that similar intercomparison studies, performed over other parts of the world’s oceans, especially coastal regions, can be very helpful in identifying shortcomings in atmospheric reanalysis products.},
doi = {10.1175/jtech-d-17-0045.1},
url = {https://www.osti.gov/biblio/1565705}, journal = {Journal of Atmospheric and Oceanic Technology},
issn = {0739-0572},
number = 1,
volume = 35,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2018},
month = {Mon Jan 01 00:00:00 EST 2018}
}