Representation of the Denmark Strait overflow in a z -coordinate eddying configuration of the NEMO (v3.6) ocean model: resolution and parameter impacts

• Published in: Geoscientific Model Development
• Main Authors: P. Colombo, B. Barnier, T. Penduff, J. Chanut, J. Deshayes, J.-M. Molines, J. Le Sommer, P. Verezemskaya, S. Gulev, A.-M. Treguier
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2020
• Subjects: Geology; QE1-996.5; Denmark Strait
• Online Access: https://doi.org/10.5194/gmd-13-3347-2020; https://doaj.org/article/d112f459677d462fa2655f1862489cc0

We investigate in this paper the sensitivity of the representation of the Denmark Strait overflow produced by a regional z -coordinate configuration of NEMO (version 3.6) to the horizontal and vertical grid resolutions and to various numerical and physical parameters. Three different horizontal resolutions, 1∕12 , 1∕36 , and <math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">1</mn><mo>/</mo><mn mathvariant="normal">60</mn><msup><mi/><mo>∘</mo></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="31pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="605737a624bdf9db2bdc788be7de848d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-13-3347-2020-ie00001.svg" width="31pt" height="14pt" src="gmd-13-3347-2020-ie00001.png"/></svg:svg> , are respectively used with 46, 75, 150, and 300 vertical levels. In the given numerical set-up, the increase in the vertical resolution did not bring improvement at eddy-permitting resolution ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">1</mn><mo>/</mo><mn mathvariant="normal">12</mn><msup><mi/><mo>∘</mo></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="31pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="2747bc57ab6b44de141632bc0eaa3f12"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gmd-13-3347-2020-ie00002.svg" width="31pt" height="14pt" src="gmd-13-3347-2020-ie00002.png"/></svg:svg> ). We find a greater dilution of the overflow as the number of vertical level increases, and the worst solution is the one with 300 vertical levels. It is found that when the local slope of the ...