During the last 7-year period (2000-2006) atmosphere circulation changes show strong influences o... more During the last 7-year period (2000-2006) atmosphere circulation changes show strong influences on the dust storm deposition dynamics and, as a result, on the primary production dynamics of the northwest African Upwelling System. From 2000 to 2006, the annual mean sea level pressure became higher ranging from 1014 to 1015 mb. Mean annual zonal wind intensity became higher (from 1.1 to 1.8 m s-1), while the mean annual meridional was reduced from 6.2 to 5.3 m s-1 at the north of the Canary Islands. Mean annual satellitederived AVHRR/NOAA SST recorded in the northwest African Upwelling became warmer in both locations, from 18.3ºC to 18.8ºC in Cape Ghir and from 19.5ºC to 20.3ºC north Canary Islands waters. CHL records from the SeaWiFS/OV-2 showed a different pattern trend. Mean annual CHL levels increased at Cape Ghir from 0.65 mg m-3 to 0.9 mg m-3 and significantly reduced from 0.59 mg m-3 to 0.31 mg m-3 at the north of the Canary Islands. Changes observed in the role of CHL during t...
IOP Conference Series: Earth and Environmental Science, 2009
During the last 7-year period (2000-2006) atmosphere circulation changes show strong influences o... more During the last 7-year period (2000-2006) atmosphere circulation changes show strong influences on the dust storm deposition dynamics and, as a result, on the primary production dynamics of the northwest African Upwelling System. From 2000 to 2006, the annual mean sea level pressure became higher ranging from 1014 to 1015 mb. Mean annual zonal wind intensity became higher (from 1.1 to 1.8 m s-1), while the mean annual meridional was reduced from 6.2 to 5.3 m s-1 at the north of the Canary Islands. Mean annual satellitederived AVHRR/NOAA SST recorded in the northwest African Upwelling became warmer in both locations, from 18.3ºC to 18.8ºC in Cape Ghir and from 19.5ºC to 20.3ºC north Canary Islands waters. CHL records from the SeaWiFS/OV-2 showed a different pattern trend. Mean annual CHL levels increased at Cape Ghir from 0.65 mg m-3 to 0.9 mg m-3 and significantly reduced from 0.59 mg m-3 to 0.31 mg m-3 at the north of the Canary Islands. Changes observed in the role of CHL during the last 7-years period could be associated to intensive dust deposition and exceptional weather warming observed in this area since 2000. However, this study focused on a 7-year period and conclusions on possible links between dust deposition and marine biochemistry activity cannot be generalized.
The combined use of data collected by multi-spectral radiometers, operating in the visible and in... more The combined use of data collected by multi-spectral radiometers, operating in the visible and infrared spectrum, and altimeter radars, operating in the microwave spectrum, allowed the detailed assessment of oceanic mesoscale dynamics in the Canary Islands area. Island-induced eddies are recurrent oceanographic structures of the region and contribute, together with other features originating from the African near-coastal zone, like upwelling filaments, to the variability of the physical and biological field of the Canarian Archipelago. The analysis of satellite-measured parameters with complementary specificities—namely brightness temperature and sea surface temperature, chlorophyll-a, as well as sea level anomaly—provided a description of the mesoscale variability around the Islands, covering in detail an entire seasonal cycle in the period 1998–1999. An overview is given of the spatial and temporal characteristics of all mesoscale features observed in the satellite imagery, including their origin, evolution and interaction with each other and their environmental surroundings.
Submarine volcanic eruptions took place at the island El Hierro (Canary Islands) between October ... more Submarine volcanic eruptions took place at the island El Hierro (Canary Islands) between October 2011 and March 2012. The event produced plumes of discoloured waters due to the discharge of volcanic matter, magmatic gases, and hydrothermal fluids. The expelled materials, which behaved like oceanic tracers, were detected from the site of the volcano to the open sea by remote-sensing techniques using different level-2 (L2) products of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. In order to assess the effect of the anomalous turbidity, three atmospheric correction schemes were evaluated: SeaWiFS Data Analysis System (SeaDAS) standard, near-infrared-shortwave-infrared (NIR-SWIR), and Management Unit of the North Sea Mathematical Models (MUMM). The comparison between them verified that the SeaDAS standard atmospheric correction was the most suitable. The downwelling diffuse attenuation coefficient at 490 nm (K d (490)) was used as a measure of plume intensity in comparison with other submarine volcanic eruptions. The MODIS-derived K d (490) values verified that the intensity of the El Hierro plume was moderate. Only in some specific situations did the values barely exceed 0.4 m-1. The remote-sensing reflectance (R rs) was used for the characterization of the affected waters. The R rs spectra also allowed a comparison with other volcanic and sulphide events reported in previous studies. Similarities were found, both with submarine volcanic eruptions in the southwestern Pacific and with sulphide events at the Namibian coast, in composition and properties of optically active water constituents. A classification schema based on K d (490) values and R rs ratios was developed and used in connection with MODIS red-green-blue (RGB) composites as well as surface current velocities from altimeter missions to investigate the spatio-temporal development of the volcanic plume. The spreading and transport of volcanic material observed at the ocean surface was caused by the predominant surface currents coupled with different mesoscale eddies. Discoloured waters were identified more than 200 km away from the eruption site. Field data from oceanographic surveys verified the high concentration of sulphur compounds in affected waters and confirmed the overestimation by the MODIS default algorithm of chlorophyll-a concentrations in the volcanic plume.
Remote Sensing of Inland, Coastal, and Oceanic Waters, 2008
During the period 2000-2005, the atmospheric dynamic showed a significant influence on the dust i... more During the period 2000-2005, the atmospheric dynamic showed a significant influence on the dust inputs dynamic and, as a result, on the primary production of the northwest African Upwelling System since 2000 to 2005. In this period, the annual mean sea level pressure became higher, ranging from 1014 to 1015 mb. Mean annual zonal wind intensity became higher (from 1.1 to 1.8 m s-1), while the mean annual meridional wind reduced from 6.2 to 5.3 m s-1. Mean annual satellite-derived AVHRR/NOAA Sea Surface Temperature recorded in the northwest African Upwelling becomes warmer with 18.3ºC to 18.8ºC in Cape Ghir, and from 19.5ºC to 20.3ºC north Canary Islands waters. Chlorophyll data from SeaWiFS/OV-2 showed a different pattern trend. Mean annual CHL levels increased at eutrophic-like waters of Cape Ghir from 0.65 mg m-3 to 0.9 mg m-. However, data were significantly reduced from 0.59 mg m-3 to 0.31 mg m-3 in oligotrophic-like waters of the Canary Islands. Changes observed in the role of CHL during the last 6-years period could be associated to intensive dust deposition and the exceptional weather warming observed in this area since 2000. However, it is addressed to a single 7 years period and conclusions on
Enrique Fernández-Perdomo∗, Jorge Cabrera-Gámez∗, Daniel Hernández-Sosa∗, Josep Isern-González∗, ... more Enrique Fernández-Perdomo∗, Jorge Cabrera-Gámez∗, Daniel Hernández-Sosa∗, Josep Isern-González∗, Antonio C. Domınguez-Brito∗, Alex Redondo, Josep Coca, Antonio G. Ramos, Enrique ´Alvarez Fanjul and Marcos Garcıa ∗ University Institute of Sistemas ...
During the last 7-year period (2000-2006) atmosphere circulation changes show strong influences o... more During the last 7-year period (2000-2006) atmosphere circulation changes show strong influences on the dust storm deposition dynamics and, as a result, on the primary production dynamics of the northwest African Upwelling System. From 2000 to 2006, the annual mean sea level pressure became higher ranging from 1014 to 1015 mb. Mean annual zonal wind intensity became higher (from 1.1 to 1.8 m s-1), while the mean annual meridional was reduced from 6.2 to 5.3 m s-1 at the north of the Canary Islands. Mean annual satellitederived AVHRR/NOAA SST recorded in the northwest African Upwelling became warmer in both locations, from 18.3ºC to 18.8ºC in Cape Ghir and from 19.5ºC to 20.3ºC north Canary Islands waters. CHL records from the SeaWiFS/OV-2 showed a different pattern trend. Mean annual CHL levels increased at Cape Ghir from 0.65 mg m-3 to 0.9 mg m-3 and significantly reduced from 0.59 mg m-3 to 0.31 mg m-3 at the north of the Canary Islands. Changes observed in the role of CHL during t...
IOP Conference Series: Earth and Environmental Science, 2009
During the last 7-year period (2000-2006) atmosphere circulation changes show strong influences o... more During the last 7-year period (2000-2006) atmosphere circulation changes show strong influences on the dust storm deposition dynamics and, as a result, on the primary production dynamics of the northwest African Upwelling System. From 2000 to 2006, the annual mean sea level pressure became higher ranging from 1014 to 1015 mb. Mean annual zonal wind intensity became higher (from 1.1 to 1.8 m s-1), while the mean annual meridional was reduced from 6.2 to 5.3 m s-1 at the north of the Canary Islands. Mean annual satellitederived AVHRR/NOAA SST recorded in the northwest African Upwelling became warmer in both locations, from 18.3ºC to 18.8ºC in Cape Ghir and from 19.5ºC to 20.3ºC north Canary Islands waters. CHL records from the SeaWiFS/OV-2 showed a different pattern trend. Mean annual CHL levels increased at Cape Ghir from 0.65 mg m-3 to 0.9 mg m-3 and significantly reduced from 0.59 mg m-3 to 0.31 mg m-3 at the north of the Canary Islands. Changes observed in the role of CHL during the last 7-years period could be associated to intensive dust deposition and exceptional weather warming observed in this area since 2000. However, this study focused on a 7-year period and conclusions on possible links between dust deposition and marine biochemistry activity cannot be generalized.
The combined use of data collected by multi-spectral radiometers, operating in the visible and in... more The combined use of data collected by multi-spectral radiometers, operating in the visible and infrared spectrum, and altimeter radars, operating in the microwave spectrum, allowed the detailed assessment of oceanic mesoscale dynamics in the Canary Islands area. Island-induced eddies are recurrent oceanographic structures of the region and contribute, together with other features originating from the African near-coastal zone, like upwelling filaments, to the variability of the physical and biological field of the Canarian Archipelago. The analysis of satellite-measured parameters with complementary specificities—namely brightness temperature and sea surface temperature, chlorophyll-a, as well as sea level anomaly—provided a description of the mesoscale variability around the Islands, covering in detail an entire seasonal cycle in the period 1998–1999. An overview is given of the spatial and temporal characteristics of all mesoscale features observed in the satellite imagery, including their origin, evolution and interaction with each other and their environmental surroundings.
Submarine volcanic eruptions took place at the island El Hierro (Canary Islands) between October ... more Submarine volcanic eruptions took place at the island El Hierro (Canary Islands) between October 2011 and March 2012. The event produced plumes of discoloured waters due to the discharge of volcanic matter, magmatic gases, and hydrothermal fluids. The expelled materials, which behaved like oceanic tracers, were detected from the site of the volcano to the open sea by remote-sensing techniques using different level-2 (L2) products of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. In order to assess the effect of the anomalous turbidity, three atmospheric correction schemes were evaluated: SeaWiFS Data Analysis System (SeaDAS) standard, near-infrared-shortwave-infrared (NIR-SWIR), and Management Unit of the North Sea Mathematical Models (MUMM). The comparison between them verified that the SeaDAS standard atmospheric correction was the most suitable. The downwelling diffuse attenuation coefficient at 490 nm (K d (490)) was used as a measure of plume intensity in comparison with other submarine volcanic eruptions. The MODIS-derived K d (490) values verified that the intensity of the El Hierro plume was moderate. Only in some specific situations did the values barely exceed 0.4 m-1. The remote-sensing reflectance (R rs) was used for the characterization of the affected waters. The R rs spectra also allowed a comparison with other volcanic and sulphide events reported in previous studies. Similarities were found, both with submarine volcanic eruptions in the southwestern Pacific and with sulphide events at the Namibian coast, in composition and properties of optically active water constituents. A classification schema based on K d (490) values and R rs ratios was developed and used in connection with MODIS red-green-blue (RGB) composites as well as surface current velocities from altimeter missions to investigate the spatio-temporal development of the volcanic plume. The spreading and transport of volcanic material observed at the ocean surface was caused by the predominant surface currents coupled with different mesoscale eddies. Discoloured waters were identified more than 200 km away from the eruption site. Field data from oceanographic surveys verified the high concentration of sulphur compounds in affected waters and confirmed the overestimation by the MODIS default algorithm of chlorophyll-a concentrations in the volcanic plume.
Remote Sensing of Inland, Coastal, and Oceanic Waters, 2008
During the period 2000-2005, the atmospheric dynamic showed a significant influence on the dust i... more During the period 2000-2005, the atmospheric dynamic showed a significant influence on the dust inputs dynamic and, as a result, on the primary production of the northwest African Upwelling System since 2000 to 2005. In this period, the annual mean sea level pressure became higher, ranging from 1014 to 1015 mb. Mean annual zonal wind intensity became higher (from 1.1 to 1.8 m s-1), while the mean annual meridional wind reduced from 6.2 to 5.3 m s-1. Mean annual satellite-derived AVHRR/NOAA Sea Surface Temperature recorded in the northwest African Upwelling becomes warmer with 18.3ºC to 18.8ºC in Cape Ghir, and from 19.5ºC to 20.3ºC north Canary Islands waters. Chlorophyll data from SeaWiFS/OV-2 showed a different pattern trend. Mean annual CHL levels increased at eutrophic-like waters of Cape Ghir from 0.65 mg m-3 to 0.9 mg m-. However, data were significantly reduced from 0.59 mg m-3 to 0.31 mg m-3 in oligotrophic-like waters of the Canary Islands. Changes observed in the role of CHL during the last 6-years period could be associated to intensive dust deposition and the exceptional weather warming observed in this area since 2000. However, it is addressed to a single 7 years period and conclusions on
Enrique Fernández-Perdomo∗, Jorge Cabrera-Gámez∗, Daniel Hernández-Sosa∗, Josep Isern-González∗, ... more Enrique Fernández-Perdomo∗, Jorge Cabrera-Gámez∗, Daniel Hernández-Sosa∗, Josep Isern-González∗, Antonio C. Domınguez-Brito∗, Alex Redondo, Josep Coca, Antonio G. Ramos, Enrique ´Alvarez Fanjul and Marcos Garcıa ∗ University Institute of Sistemas ...
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