Relationship between Sea Surface Drag Coefficient and Wave State
The sea surface drag coefficient plays an important role in momentum transmission between the atmosphere and the ocean, which is affected by ocean waves. The total air–sea momentum flux consists of effective momentum flux and sea spray momentum flux. Sea spray momentum flux involves sea surface drag...
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| Format: | Article |
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MDPI AG
2021-11-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/9/11/1248 |
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| author | Jian Shi Zhihao Feng Yuan Sun Xueyan Zhang Wenjing Zhang Yi Yu |
| author_facet | Jian Shi Zhihao Feng Yuan Sun Xueyan Zhang Wenjing Zhang Yi Yu |
| author_sort | Jian Shi |
| collection | DOAJ |
| description | The sea surface drag coefficient plays an important role in momentum transmission between the atmosphere and the ocean, which is affected by ocean waves. The total air–sea momentum flux consists of effective momentum flux and sea spray momentum flux. Sea spray momentum flux involves sea surface drag, which is largely affected by the ocean wave state. Under strong winds, the sea surface drag coefficient (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula>) does not increase linearly with the increasing wind speed, namely, the increase of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula> is inhibited by strong winds. In this study, a sea surface drag coefficient is constructed that can be applied to the calculation of the air–sea momentum flux under high wind speed. The sea surface drag coefficient also considers the influence of wave state and sea spray droplets generated by wave breaking. Specially, the wave-dependent sea spray generation function is employed to calculate sea spray momentum flux. This facilitates the analysis not only on the sensitivity of the sea spray momentum flux to wave age, but also on the effect of wave state on the effective <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula> (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mrow><mi>D</mi><mo>,</mo><mo> </mo><mi>e</mi><mi>f</mi><mi>f</mi></mrow></msub></mrow></semantics></math></inline-formula>) under strong winds. Our results indicate that wave age plays an important role in determining <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula>. When the wave age is >0.4, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula> decreases with the wave age. However, when the wave age is ≤0.4, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula> increases with the wave age at low and moderate wind speeds but tends to decrease with the wave age at high wind speeds. |
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| language | English |
| last_indexed | 2024-03-10T05:23:12Z |
| publishDate | 2021-11-01 |
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| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-f048596a2e5549599deb96edf145eecc2023-11-22T23:53:57ZengMDPI AGJournal of Marine Science and Engineering2077-13122021-11-01911124810.3390/jmse9111248Relationship between Sea Surface Drag Coefficient and Wave StateJian Shi0Zhihao Feng1Yuan Sun2Xueyan Zhang3Wenjing Zhang4Yi Yu5College of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, ChinaCollege of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, ChinaCollege of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, ChinaCollege of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, ChinaCollege of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, ChinaCollege of Meteorology and Oceanography, National University of Defense Technology, Changsha 410073, ChinaThe sea surface drag coefficient plays an important role in momentum transmission between the atmosphere and the ocean, which is affected by ocean waves. The total air–sea momentum flux consists of effective momentum flux and sea spray momentum flux. Sea spray momentum flux involves sea surface drag, which is largely affected by the ocean wave state. Under strong winds, the sea surface drag coefficient (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula>) does not increase linearly with the increasing wind speed, namely, the increase of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula> is inhibited by strong winds. In this study, a sea surface drag coefficient is constructed that can be applied to the calculation of the air–sea momentum flux under high wind speed. The sea surface drag coefficient also considers the influence of wave state and sea spray droplets generated by wave breaking. Specially, the wave-dependent sea spray generation function is employed to calculate sea spray momentum flux. This facilitates the analysis not only on the sensitivity of the sea spray momentum flux to wave age, but also on the effect of wave state on the effective <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula> (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mrow><mi>D</mi><mo>,</mo><mo> </mo><mi>e</mi><mi>f</mi><mi>f</mi></mrow></msub></mrow></semantics></math></inline-formula>) under strong winds. Our results indicate that wave age plays an important role in determining <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula>. When the wave age is >0.4, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula> decreases with the wave age. However, when the wave age is ≤0.4, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>D</mi></msub></mrow></semantics></math></inline-formula> increases with the wave age at low and moderate wind speeds but tends to decrease with the wave age at high wind speeds.https://www.mdpi.com/2077-1312/9/11/1248sea surface drag coefficientwave statewave agesea spray droplets |
| spellingShingle | Jian Shi Zhihao Feng Yuan Sun Xueyan Zhang Wenjing Zhang Yi Yu Relationship between Sea Surface Drag Coefficient and Wave State Journal of Marine Science and Engineering sea surface drag coefficient wave state wave age sea spray droplets |
| title | Relationship between Sea Surface Drag Coefficient and Wave State |
| title_full | Relationship between Sea Surface Drag Coefficient and Wave State |
| title_fullStr | Relationship between Sea Surface Drag Coefficient and Wave State |
| title_full_unstemmed | Relationship between Sea Surface Drag Coefficient and Wave State |
| title_short | Relationship between Sea Surface Drag Coefficient and Wave State |
| title_sort | relationship between sea surface drag coefficient and wave state |
| topic | sea surface drag coefficient wave state wave age sea spray droplets |
| url | https://www.mdpi.com/2077-1312/9/11/1248 |
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