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Document Type |
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Thesis |
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Document Title |
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ESTIMATING SEA SURFACE HEIGHT ANOMALIES AND GEOSTROPHIC CURRENT IN THE RED SEA FROM SATELLITE ALTIMETRY تقدير الحيود في منسوب سطح البحر والتيارات الجيوستروفية في البحر الاحمر من بيانات الاقمار الصناعية |
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Subject |
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Faculty of Marine Sciences |
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Document Language |
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Arabic |
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Abstract |
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Satellite altimetry data are facing big challenges near the coasts. These challenges arise due to the fundamental difficulties of correction and land contamination in the footprint, which result in rejection of these data near the coast. Several studies have been carried out to extend these data towards the coast. Over the Red Sea, altimetry data consist of gaps, which extend to about 30–50 km from the coast. Two methods are used for processing and extending Jason-2 satellite altimetry sea level anomalies (SLAs) towards the Red Sea coast; Fourier Series Model (FSM), and the polynomial sum of sine model (SSM). FSM model technique uses Fourier series and statistical analysis reflects strong relationship with both the observation and AVISO data, with strong and positive correlation. The second prediction technique, SSM model, depends on the polynomial sum of sine, and does not reflect any relationship with the observations and AVISO data close to the coast and the correlation coefficient (CC) is weak and negative. The FSM model output results in SLA data significantly better and more accurate than the SSM model output Hence, the sea level anomaly (SLA) data from Jason-2 have been reprocessed and extended towards the coast of the Red Sea and merged with AVISO data at the offshore region. This processing has been applied to build a gridded dataset to achieve the best results for the SLA and geostrophic current. The results obtained from the new extended data at the coast are more consistent with the observed data (conductivity–temperature– depth, CTD) and hence geostrophic current calculation. The patterns of SLA distribution and geostrophic currents are divided into two seasons: winter (October–May) and summer (June–September). The geostrophic currents in summer are flowing southward over the Red Sea except for narrow northward flow along the east coast. In winter, currents flow to the north for the entire Red Sea except for a small southward flow near the central eastern and western coast. This flow is modified by the presence of cyclonic and anticyclonic eddies, which are more concentrated in the central and northern Red Sea. The results show anticyclonic eddies (AEs) on the eastern side of the Red Sea and cyclonic eddies (CEs) on the western side during winter. In summer, cyclonic eddies are more dominant for the entire Red Sea. The result shows a change in some eddies from anticyclonic during winter to cyclonic during summer in the north between 26.3 and 27.5° N. Furthermore, the life span of cyclonic eddies is longer than that of anticyclonic eddies. |
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Supervisor |
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Dr. Abdullah Mohammed Al-Subhi |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1441 AH
2019 AD |
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Added Date |
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Thursday, October 24, 2019 |
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Researchers
| أحمد محمد تقي | Taqi, Ahmed Mohammed | Researcher | Doctorate | |
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