Waves in the Red Sea: Response to monsoonal and mountain gap winds

Handle URI:
http://hdl.handle.net/10754/600186
Title:
Waves in the Red Sea: Response to monsoonal and mountain gap winds
Authors:
Ralston, David K.; Jiang, Houshuo; Farrar, J. Thomas
Abstract:
An unstructured grid, phase-averaged wave model forced with winds from a high resolution atmospheric model is used to evaluate wind wave conditions in the Red Sea over an approximately 2-year period. The Red Sea lies in a narrow rift valley, and the steep topography surrounding the basin steers the dominant wind patterns and consequently the wave climate. At large scales, the model results indicated that the primary seasonal variability in waves was due to the monsoonal wind reversal. During the winter, monsoon winds from the southeast generated waves with mean significant wave heights in excess of 2. m and mean periods of 8. s in the southern Red Sea, while in the northern part of the basin waves were smaller, shorter period, and from northwest. The zone of convergence of winds and waves typically occurred around 19-20°N, but the location varied between 15 and 21.5°N. During the summer, waves were generally smaller and from the northwest over most of the basin. While the seasonal winds oriented along the axis of the Red Sea drove much of the variability in the waves, the maximum wave heights in the simulations were not due to the monsoonal winds but instead were generated by localized mountain wind jets oriented across the basin (roughly east-west). During the summer, a mountain wind jet from the Tokar Gap enhanced the waves in the region of 18 and 20°N, with monthly mean wave heights exceeding 2. m and maximum wave heights of 14. m during a period when the rest of the Red Sea was relatively calm. Smaller mountain gap wind jets along the northeast coast created large waves during the fall and winter, with a series of jets providing a dominant source of wave energy during these periods. Evaluation of the wave model results against observations from a buoy and satellites found that the spatial resolution of the wind model significantly affected the quality of the wave model results. Wind forcing from a 10-km grid produced higher skills for waves than winds from a 30-km grid, largely due to under-prediction of the mean wind speed and wave height with the coarser grid. The 30-km grid did not resolve the mountain gap wind jets, and thus predicted lower wave heights in the central Red Sea during the summer and along the northeast coast in the winter. © 2013 Elsevier Ltd.
Citation:
Ralston DK, Jiang H, Farrar JT (2013) Waves in the Red Sea: Response to monsoonal and mountain gap winds. Continental Shelf Research 65: 1–13. Available: http://dx.doi.org/10.1016/j.csr.2013.05.017.
Publisher:
Elsevier BV
Journal:
Continental Shelf Research
KAUST Grant Number:
USA00001; USA00002; KSA00011
Issue Date:
Aug-2013
DOI:
10.1016/j.csr.2013.05.017
Type:
Article
ISSN:
0278-4343
Sponsors:
We thank Casey Dietrich for providing the SWAN-ADCIRC code and Changshen Chen for the model grid bathymetry. This research is based on work supported by Award nos. USA00001, USA00002, KSA00011, made by the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia.
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Full metadata record

DC FieldValue Language
dc.contributor.authorRalston, David K.en
dc.contributor.authorJiang, Houshuoen
dc.contributor.authorFarrar, J. Thomasen
dc.date.accessioned2016-02-28T06:44:42Zen
dc.date.available2016-02-28T06:44:42Zen
dc.date.issued2013-08en
dc.identifier.citationRalston DK, Jiang H, Farrar JT (2013) Waves in the Red Sea: Response to monsoonal and mountain gap winds. Continental Shelf Research 65: 1–13. Available: http://dx.doi.org/10.1016/j.csr.2013.05.017.en
dc.identifier.issn0278-4343en
dc.identifier.doi10.1016/j.csr.2013.05.017en
dc.identifier.urihttp://hdl.handle.net/10754/600186en
dc.description.abstractAn unstructured grid, phase-averaged wave model forced with winds from a high resolution atmospheric model is used to evaluate wind wave conditions in the Red Sea over an approximately 2-year period. The Red Sea lies in a narrow rift valley, and the steep topography surrounding the basin steers the dominant wind patterns and consequently the wave climate. At large scales, the model results indicated that the primary seasonal variability in waves was due to the monsoonal wind reversal. During the winter, monsoon winds from the southeast generated waves with mean significant wave heights in excess of 2. m and mean periods of 8. s in the southern Red Sea, while in the northern part of the basin waves were smaller, shorter period, and from northwest. The zone of convergence of winds and waves typically occurred around 19-20°N, but the location varied between 15 and 21.5°N. During the summer, waves were generally smaller and from the northwest over most of the basin. While the seasonal winds oriented along the axis of the Red Sea drove much of the variability in the waves, the maximum wave heights in the simulations were not due to the monsoonal winds but instead were generated by localized mountain wind jets oriented across the basin (roughly east-west). During the summer, a mountain wind jet from the Tokar Gap enhanced the waves in the region of 18 and 20°N, with monthly mean wave heights exceeding 2. m and maximum wave heights of 14. m during a period when the rest of the Red Sea was relatively calm. Smaller mountain gap wind jets along the northeast coast created large waves during the fall and winter, with a series of jets providing a dominant source of wave energy during these periods. Evaluation of the wave model results against observations from a buoy and satellites found that the spatial resolution of the wind model significantly affected the quality of the wave model results. Wind forcing from a 10-km grid produced higher skills for waves than winds from a 30-km grid, largely due to under-prediction of the mean wind speed and wave height with the coarser grid. The 30-km grid did not resolve the mountain gap wind jets, and thus predicted lower wave heights in the central Red Sea during the summer and along the northeast coast in the winter. © 2013 Elsevier Ltd.en
dc.description.sponsorshipWe thank Casey Dietrich for providing the SWAN-ADCIRC code and Changshen Chen for the model grid bathymetry. This research is based on work supported by Award nos. USA00001, USA00002, KSA00011, made by the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia.en
dc.publisherElsevier BVen
dc.subjectModel grid resolutionen
dc.subjectMountain gap windsen
dc.subjectRed Seaen
dc.subjectSpectral wave modelen
dc.subjectUnstructured griden
dc.subjectWind wavesen
dc.titleWaves in the Red Sea: Response to monsoonal and mountain gap windsen
dc.typeArticleen
dc.identifier.journalContinental Shelf Researchen
dc.contributor.institutionWoods Hole Oceanographic Institution, Woods Hole, United Statesen
kaust.grant.numberUSA00001en
kaust.grant.numberUSA00002en
kaust.grant.numberKSA00011en
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