Date

2011

Author

Sancak, Serkan

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SeaWiFS was collecting ocean color data since 1997. This means chlorophyll-a data for more than ten years. Since, SeaWiFS Chl-a data is validated for Black Sea this data set can be used for analysis. Nevertheless, the data is not gap free due to cloud effect. One of the main objectives of this work is to obtain a gap free, complete Chl-a data set for the Black Sea. For this purpose DINEOF method will be used. EOF analysis is a by-product of this method and the results are used to summarize some temporal and spatial Chl-a behavior for the time period of data set. Some major findings are: General low productive phase with relatively low chlorophyll concentrations over the basin starts by the beginning of spring season and ends by the beginning of autumn except year 1999, in which high chlorophyll period begins by the end of summer. There is a gradual increase of Chl-a concentration towards east in winter and spring, and a similar change towards south in spring and summer. According to temporal analysis, there is an absence of a typical annual pattern repeating every year. Instead, there are appreciable interannual variability with some years having maximum concentrations in spring and summer, that may be even higher than the basin averaged values of winter and autumn seasons, whereas some years possess no definitive spring – summer maximum. Another major finding is that, the long-term mean chlorophyll distribution reveals an almost horizontally uniform interior basin with concentrations of about 1.0 mg/m3 that increases to 1.5 mg/m3 range along a narrow coastal band and exceeds 3 mg/m3 along the western coastal zone. A switch to lower concentrations (up to 0.5 mg/m3) within the interior basin takes place in the spring and summer months, thus giving rise to more pronounced onshore-offshore gradients around the basin. The other main objective of this study is to regionalize the Black Sea basin according to its Chl-a content. The determined provinces will also be stated as bioms throughout the thesis, since, Chl-a is an indicator of primary production. Separating the oceans into its bioms using ocean color (Chl-a) data is applied to various seas so far. Though, the studies that include Black Sea, define the basin as a single province. This is the main motivation for the objective. By using more than ten years of data, the Black Sea is separated into nine provinces according to its Chl-a content. Nevertheless, the main reference region map includes only six provinces. A major outcome is that, the interior basin is formed by one composite cell contrary to the two separated gyres for the case of circulation dynamics.

Subject Keywords

Seawater

URI

http://etd.lib.metu.edu.tr/upload/12613518/index.pdf
https://hdl.handle.net/11511/21500

Collections

Graduate School of Marine Sciences, Thesis