Improved capabilities of global ocean reanalyses for analysing sea level variability near the Atlantic and Gulf of Mexico Coastal U.S.

Bibliographic Details
Title: Improved capabilities of global ocean reanalyses for analysing sea level variability near the Atlantic and Gulf of Mexico Coastal U.S.
Authors: Xue Feng, Matthew J. Widlansky, Magdalena A. Balmaseda, Hao Zuo, Claire M. Spillman, Grant Smith, Xiaoyu Long, Philip Thompson, Arun Kumar, Gregory Dusek, William Sweet
Source: Frontiers in Marine Science, Vol 11 (2024)
Publisher Information: Frontiers Media S.A., 2024.
Publication Year: 2024
Collection: LCC:Science
LCC:General. Including nature conservation, geographical distribution
Subject Terms: ocean reanalysis, data assimilation, coastal sea level, western boundary current, eddy-resolving models, satellite altimetry, Science, General. Including nature conservation, geographical distribution, QH1-199.5
More Details: Realistic representation of monthly sea level anomalies in coastal regions has been a challenge for global ocean reanalyses. This is especially the case in coastal regions where sea levels are influenced by western boundary currents such as near the U.S. Atlantic Coast and the Gulf of Mexico. For these regions, most ocean reanalyses compare poorly to observations. Problems in reanalyses include errors in data assimilation and horizontal resolutions that are too coarse to simulate energetic currents like the Gulf Stream and Loop Current System. However, model capabilities are advancing with improved data assimilation and higher resolution. Here, we show that some current-generation ocean reanalyses produce monthly sea level anomalies with improved skill when compared to satellite altimetry observations of sea surface heights. Using tide gauge observations for coastal verification, we find the highest skill associated with the GLORYS12 and HYCOM ocean reanalyses. Both systems assimilate altimetry observations and have eddy-resolving horizontal resolutions (1/12°). We found less skill in three other ocean reanalyses (ACCESS-S2, ORAS5, and ORAP6) with coarser, though still eddy-permitting, resolutions (1/4°). The operational reanalysis from ECMWF (ORAS5) and their pilot reanalysis (ORAP6) provide an interesting comparison because the latter assimilates altimetry globally and with more weight, as well as assimilating ocean observations over continental shelves. We find these attributes associated with improved skill near many tide gauges. We also assessed an older reanalysis (CFSR), which has the lowest skill likely due to its lower resolution (1/2°) and lack of altimetry assimilation. ACCESS-S2 likewise does not assimilate altimetry, although its skill is much better than CFSR and only somewhat lower than ORAS5. Since coastal flooding is influenced by sea level anomalies, the recent development of skilful ocean reanalyses on monthly timescales may be useful for better understanding the physical processes associated with flood risks.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2296-7745
Relation: https://www.frontiersin.org/articles/10.3389/fmars.2024.1338626/full; https://doaj.org/toc/2296-7745
DOI: 10.3389/fmars.2024.1338626
Access URL: https://doaj.org/article/2bc75fe681d3406a98273e1a49c26b9c
Accession Number: edsdoj.2bc75fe681d3406a98273e1a49c26b9c
Database: Directory of Open Access Journals
More Details
ISSN:22967745
DOI:10.3389/fmars.2024.1338626
Published in:Frontiers in Marine Science
Language:English