Mesoscale frontal structures in the Canary Upwelling System: New front and filament detection algorithms applied to spatial and temporal patterns

Nieto, Karen; Demarcq, Hervé; McClatchie, Sam

doi:10.1016/j.rse.2012.03.028

Cited by 99 publications

(67 citation statements)

References 22 publications

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“…These centres are due to the different wind conditions, variability in coastal topography, and the continental platform, giving rise to four well-differentiated zones along it delimited by the coasts' largest capes (see Figure 2), as proposed in García-Weil (1998); Garcia-Weil et al (2000); Barton et al (1998) ;Nieto, Demarcq, and McClatchie (2012), although with different limits. It so happens that there is frequent cloud cover in that zone, which causes the upwelling to be partially covered by clouds in most of the satellite images processed, leaving only pieces of it in view.…”

Section: Introductionmentioning

confidence: 85%

A location-based approach to the classification of mesoscale oceanic structures in SeaWiFS and Aqua-MODIS images of Northwest Africa

Vidal-Fernandez

Piedra-Fernández

Almendros-Jiménez

et al. 2015

International Journal of Remote Sensing

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This study presents a different approach to the classification of Mesoscale Oceanic Structures (MOS) present in the Northwest African area, based on their location. The main improvement stems from the partition of this area in four large zones perfectly differentiated by their morphological characteristics, with attention to seafloor topography and coastal relief. This decomposition makes it easier to recognize structures under adverse conditions, basically the presence of clouds partly hiding them. This is observed particularly well in upwellings, which are usually very large structures with a different morphology and genesis in each zone. This approach not only improves the classification of the upwellings, but also makes it possible to analyse changes in the MOS over time, thereby improving the prediction of its morphological evolution. To identify and label the MOS classified in the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Aqua-MODIS (Moderate Resolution Imaging Spectroradiometer) chlorophyll-a and temperature images, we used a tool specifically designed by our group for this purpose and which has again shown its validity in this new proposal.

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Section: Introductionmentioning

confidence: 85%

A location-based approach to the classification of mesoscale oceanic structures in SeaWiFS and Aqua-MODIS images of Northwest Africa

Vidal-Fernandez

Piedra-Fernández

Almendros-Jiménez

et al. 2015

International Journal of Remote Sensing

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“…Upwelling frontal systems exhibit instabilities that generate other mesoscale and sub-mesoscale thermal structures, such as complex imbricate fronts and filaments, which are always associated with strong surface chlorophyll gradients [7].…”

Section: A Upwelling Patternmentioning

confidence: 99%

Modeling of Coastal Upwelling Using Spatiogram and Structuring Elements

Wikantika¹

2018

Preprint

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Abstract-Upwelling is an oceanographic phenomenon where the mass of water from the sea floor, cold temperature and nutrient rich, moving up to the sea surface. Upwelling could be happened due to the interaction between the surface water with the wind, ocean currents, Ekman transport, and the Coriolis force, so there is a special characteristic of the upwelling waters. Nevertheless, a common indicator of upwelling is the sea surface temperature (SST) lower than the surrounding areas, high concentrations of chlorophyll-a, as well as high salinity and density. In coastal upwelling, a lower temperature will be detected near the coast, while warmer temperatures towards offshore. This condition leads to form unique patterns contour of sea surface temperature. By using the data of SST derived from satellites, SST can be represented with the color and/or contour. Each color pixel value represents a particular SST. The initial phase of this research is to develop a model for the identification of upwelling based on the pixel and contour patterns. By using sea surface temperature data, the average SST (each month) were analyzed and generate contour lines. Contour lines are formed from the pixels that have the same temperature value. By calculating the distance between pixels in the same temperature class and the distance to the surrounding pixels, we have been developing a model for the detection of upwelling.

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“…For the purpose of removing SST images with heavy cloud occlusions and artifacts over the area of interest, each SST image is kept for further analysis if it has at least 70% of valid information (no clouds or missing pixels) in the area between the coast and 200 km offshore [11].…”

Section: Satellite Datamentioning

confidence: 99%

On Detectability of Moroccan Coastal Upwelling in Sea Surface Temperature Satellite Images

Tamim

Minaoui

Daoudi

et al. 2014

Advances in Visual Computing

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Abstract. This work aims at automatically identify the upwelling areas in coastal ocean of Morocco using the Sea Surface Temperature (SST) satellite images. This has been done by using the fuzzy clustering technique. The proposed approach is started with the application of Gustafson-Kessel clustering algorithm in order to detect groups in each SST image with homogenous and non-overlapping temperature, resulting in a c-partitioned labeled image. Cluster validity indices are used to select the c-partition that best reproduces the shape of upwelling areas. An area opening technique is developed that is used to filter out the residuals noise and fine structures in offshore waters not belonging to the upwelling regions. The developed algorithm is applied and adjusted over a database of 70 SST images from years 2007 and 2008, covering the southern part of Moroccan atlantic coast. The system was evaluated by an oceanographer and provided acceptable results for a wide variety of oceanographic conditions.

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Mesoscale frontal structures in the Canary Upwelling System: New front and filament detection algorithms applied to spatial and temporal patterns

Cited by 99 publications

References 22 publications

A location-based approach to the classification of mesoscale oceanic structures in SeaWiFS and Aqua-MODIS images of Northwest Africa

A location-based approach to the classification of mesoscale oceanic structures in SeaWiFS and Aqua-MODIS images of Northwest Africa

Modeling of Coastal Upwelling Using Spatiogram and Structuring Elements

On Detectability of Moroccan Coastal Upwelling in Sea Surface Temperature Satellite Images

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