ABSTRACT ABSTRACT During the past 40 years the fisheries productivity of the world has been decli... more ABSTRACT ABSTRACT During the past 40 years the fisheries productivity of the world has been declining due to pressures from overfishing, habitat change, pollution, and climate change. Sustainable use of marine resources requires effective monitoring and management of the world’s fish stocks. Remote sensing techniques are being used to help manage fisheries at sustainable levels, while also guiding fishing fleets to locate fish schools more efficiently. Fish tend to aggregate in ocean areas that exhibit conditions favored by specific fish species. Some of the relevant oceanographic conditions, such as sea surface temperature, ocean color (productivity) and oceanic fronts, which strongly influence natural fluctuations of fish stocks, can be observed and measured by remote sensors on satellites and aircraft. The remotely sensed data are provided in near-real time to help fishermen save fuel and ship time during their search for fish; to modelers who produce fisheries forecasts; and to scientists who help develop strategies for sustainable fisheries management. This article describes how acoustic, optical and radar sensors on ships, satellites and aircraft are used with forecast models to improve the management and harvesting of fisheries resources.
Environmental Research Engineering and Management, 2009
Advances in sensor design and data analysis techniques are now making remote sensing systems prac... more Advances in sensor design and data analysis techniques are now making remote sensing systems practical and attractive for coastal ecosystem research and management. Multispectral and hyperspectral imagers are available for mapping coastal land cover and concentrations of organic/inorganic suspended particles and dissolved substances in coastal waters. Thermal infrared scanners can map sea surface temperatures accurately and chart coastal currents, while microwave radiometers can measure ocean salinity, soil moisture and other hydrologic parameters. Radar imagers, scatterometers and altimeters provide information on ocean waves, ocean winds, sea surface height and coastal currents. Using airborne lidars one can produce bathymetric maps, even in moderately turbid coastal waters. Since coastal ecosystems have high spatial complexity and temporal variability, they frequently have to be observed from both, satellite and aircraft , in order to obtain the required spatial, spectral and temporal resolutions. A reliable field data collection approach using ships, buoys, and field instruments with a valid sampling scheme is required to calibrate and validate the remotely sensed information. This paper presents a brief overview of recent advances in coastal remote sensing.
Our long-term goal is to set up a database of ocean internal waves observed from US space shuttle... more Our long-term goal is to set up a database of ocean internal waves observed from US space shuttles. Each case includes photographs, interpretation maps, quantitative data and information extracted from images, and boundary conditions collected by in situ measurements. The database will be publicly accessible. Users, who are interested in ocean internal waves, may search for the information they need through the network.
Alternative dark-bright patterns on ERS-1 synthetic aperture radar (SAR) images of the west side ... more Alternative dark-bright patterns on ERS-1 synthetic aperture radar (SAR) images of the west side of the Taiwan Strait taken on December 8, 1994, were recognized to be the sea surface signature of a coastal lee wave. Such waves are called coastal lee waves because they occur along the lee side of the coast. The coastal lee waves appeared in the form of a wave packet distributed within an offshore band 20-40 km wide. The first packet, which occurred in the northern portion of the observed area, contained six waves with variable wavelengths (defined as the spatial separation between two waves) from 1.7 to 2.7 km. The second packet, in the middle, contained 10 waves with a relatively uniform wavelength of 4.2 kin. The third packet, in the southern portion, contained 17 waves with an average wavelength of 2.0 km. The crest lengths were from 20 to 80 km. Local meteorologic parameters observed simultaneously at Fuzhou, China, close to the imaged area, showed an offshore wind of 1.5-3.5 m/s and a land surface air temperature of 19øC, which was 4øC lower than the sea surface temperature (SST). Thus the lower atmospheric boundary conditions at imaging time were very favorable both for generating the land breeze circulation and small wind waves on the sea surface, which are in the Bragg-scattering wavelength band of the C band ERS-1 SAR. A physical model of a three-layer atmosphere was developed in order to explain how the !and breeze circulation can generate the coastal lee waves. The results showed that the vertical velocity disturbance caused by the wind convergence at the land breeze frontal zone is of vitaJ importance for the generation of coastal lee waves, and the model gave very good estimates of the processes observed. The S AR imaging mechanisms of the waves were analyzed in detail. The differences between coastal lee waves and ocean internal waves, which appear as similar alternative dark-bright patterns on SAR images, were also discussed. Observations showed that mountain lee waves are stationary waves and have a typical wavelength of 10 km, ranging from 2-3 to 40-45 km, and a vertical amplitude of the same order of height as the mountain generating them [Gossard and Hooke, 1975; Panchev, 1985]. Lee waves, which are analogous to mountain lee waves but caused by an isolated linear island, have recently been observed by Vachon et al. [1994] using a European Remote Sensing Satellite (ERS-1) synthetic aperture radar (SAR) image. They found that a packet of six atmospheric lee waves with a wavelength of 7.6 km occurred on the lee side of the island Hopen in the Barents Sea, which is located near 76.5øN, 25.0øE, southeast of Svalbard, Norway. From another ERS-1 SAR image a nonlinear wave disturbance with an average wavelength of 2.3 km was identified in the marine atmosphere 30 km offshore in the German Bight of the North Sea by Alpers and Stilke [1996]. In this study we will investigate another kind of lee waves, which is different from the above mentioned ones. The waves were observed on ERS-1 SAR images 7979 7980 ZHENG ET AL.: COASTAL LEE WAVES ON ERS-1 SAR IMAGES of the Taiwan Strait and characterized by their occurrence being associated with the coastal environment, i.e., the transition region between marine and terrigenous air masses. The waves occurred in the form of wave packets along the lee side of the coast. The wave crest lines were nearly parallel to the coastline and reached 80 km long. According to this close association of its occurrence with the coast, a unique feature, we define this kind of lee wave as a coastal lee wave.
Http Dx Doi Org 10 2112 Jcoastres D 11 00176 1, 2012
Huang, J. and Klemas, V., 2012. Using remote sensing of land cover change in coastal watersheds t... more Huang, J. and Klemas, V., 2012. Using remote sensing of land cover change in coastal watersheds to predict downstream water quality. Journal of Coastal Research, 28(4), 930-944. West Palm Beach (Florida), ISSN 0749-0208.
Satellite remote sensors cannot see far beneath the surface layers of the ocean. Yet many importa... more Satellite remote sensors cannot see far beneath the surface layers of the ocean. Yet many important ocean processes and features are located well below the surface and at considerable depths. Examples include Mediterranean Eddies (meddies), mixed layer depth, internal waves, and bottom topography. Deeper ocean remote sensing is becoming even more important because recent data seem to indicate that the deeper ocean is responding to climate variability and change. Many of these subsurface phenomena have surface manifestations which can be interpreted with the help of models to derive key parameters of deeper ocean processes. The objective of this paper is to provide an overview of satellite remote sensing and modeling techniques which enable scientists to characterize subsurface and deeper ocean processes and features and to present some new results.
Radiance measurements using a hand-held radiometer configured to match LANDSAT TM bands 3-5 were ... more Radiance measurements using a hand-held radiometer configured to match LANDSAT TM bands 3-5 were compiled from Spartina ang/ica plots in five geographically separate marshes in Brittany, France. Aboveground biomass of the plots was harvested following the determination of radiance. Simple regression models employing a vegetation index to predict S. anglica leaf, live and total aboveground biomass from spectral radiance values were derived from data collected in one of the marshes. Radiance measurements gathered in the other four marshes (test marshes) were substituted into the biomass estimation models. In three of the test marshes, the mean model-predicted leaf and live biomass were within 1-13 per cent of the harvest values. In the other test marsh, dead material located near the top of the canopy caused biomass to be underestimated. Total (live and dead) biomass predictions were not close to harvest values in any of the marshes. This study demonstrated that a simple regression equation relating radiance data (in the form of a vegetation index) to S. ang/ica biomass in one marsh can be employed to accurately predict leaf and live S. ang/ica biomass in other, distant, marshes.
ABSTRACT Abstract With the coastal population increasing, storms have been inflicting unprecedent... more ABSTRACT Abstract With the coastal population increasing, storms have been inflicting unprecedented losses to coastal communities. Coastal agencies require advance information on the predicted path, intensity and progress of a storm and associated waves and storm surges, near-real-time information during the peak of the storm to monitor flooding and control rescue operations, and post-storm reports to assess the damage and plan and implement the recovery. The same holds true for other disasters, such as oil spills and algal blooms. Coastal communities are also facing a rising sea level, caused mainly by global warming. Airborne and satellite remote sensors, such as multispectral imagers, Lidar and radar, are now able to provide most of the information required for emergency response and coastal management.
ABSTRACT ABSTRACT During the past 40 years the fisheries productivity of the world has been decli... more ABSTRACT ABSTRACT During the past 40 years the fisheries productivity of the world has been declining due to pressures from overfishing, habitat change, pollution, and climate change. Sustainable use of marine resources requires effective monitoring and management of the world’s fish stocks. Remote sensing techniques are being used to help manage fisheries at sustainable levels, while also guiding fishing fleets to locate fish schools more efficiently. Fish tend to aggregate in ocean areas that exhibit conditions favored by specific fish species. Some of the relevant oceanographic conditions, such as sea surface temperature, ocean color (productivity) and oceanic fronts, which strongly influence natural fluctuations of fish stocks, can be observed and measured by remote sensors on satellites and aircraft. The remotely sensed data are provided in near-real time to help fishermen save fuel and ship time during their search for fish; to modelers who produce fisheries forecasts; and to scientists who help develop strategies for sustainable fisheries management. This article describes how acoustic, optical and radar sensors on ships, satellites and aircraft are used with forecast models to improve the management and harvesting of fisheries resources.
Environmental Research Engineering and Management, 2009
Advances in sensor design and data analysis techniques are now making remote sensing systems prac... more Advances in sensor design and data analysis techniques are now making remote sensing systems practical and attractive for coastal ecosystem research and management. Multispectral and hyperspectral imagers are available for mapping coastal land cover and concentrations of organic/inorganic suspended particles and dissolved substances in coastal waters. Thermal infrared scanners can map sea surface temperatures accurately and chart coastal currents, while microwave radiometers can measure ocean salinity, soil moisture and other hydrologic parameters. Radar imagers, scatterometers and altimeters provide information on ocean waves, ocean winds, sea surface height and coastal currents. Using airborne lidars one can produce bathymetric maps, even in moderately turbid coastal waters. Since coastal ecosystems have high spatial complexity and temporal variability, they frequently have to be observed from both, satellite and aircraft , in order to obtain the required spatial, spectral and temporal resolutions. A reliable field data collection approach using ships, buoys, and field instruments with a valid sampling scheme is required to calibrate and validate the remotely sensed information. This paper presents a brief overview of recent advances in coastal remote sensing.
Our long-term goal is to set up a database of ocean internal waves observed from US space shuttle... more Our long-term goal is to set up a database of ocean internal waves observed from US space shuttles. Each case includes photographs, interpretation maps, quantitative data and information extracted from images, and boundary conditions collected by in situ measurements. The database will be publicly accessible. Users, who are interested in ocean internal waves, may search for the information they need through the network.
Alternative dark-bright patterns on ERS-1 synthetic aperture radar (SAR) images of the west side ... more Alternative dark-bright patterns on ERS-1 synthetic aperture radar (SAR) images of the west side of the Taiwan Strait taken on December 8, 1994, were recognized to be the sea surface signature of a coastal lee wave. Such waves are called coastal lee waves because they occur along the lee side of the coast. The coastal lee waves appeared in the form of a wave packet distributed within an offshore band 20-40 km wide. The first packet, which occurred in the northern portion of the observed area, contained six waves with variable wavelengths (defined as the spatial separation between two waves) from 1.7 to 2.7 km. The second packet, in the middle, contained 10 waves with a relatively uniform wavelength of 4.2 kin. The third packet, in the southern portion, contained 17 waves with an average wavelength of 2.0 km. The crest lengths were from 20 to 80 km. Local meteorologic parameters observed simultaneously at Fuzhou, China, close to the imaged area, showed an offshore wind of 1.5-3.5 m/s and a land surface air temperature of 19øC, which was 4øC lower than the sea surface temperature (SST). Thus the lower atmospheric boundary conditions at imaging time were very favorable both for generating the land breeze circulation and small wind waves on the sea surface, which are in the Bragg-scattering wavelength band of the C band ERS-1 SAR. A physical model of a three-layer atmosphere was developed in order to explain how the !and breeze circulation can generate the coastal lee waves. The results showed that the vertical velocity disturbance caused by the wind convergence at the land breeze frontal zone is of vitaJ importance for the generation of coastal lee waves, and the model gave very good estimates of the processes observed. The S AR imaging mechanisms of the waves were analyzed in detail. The differences between coastal lee waves and ocean internal waves, which appear as similar alternative dark-bright patterns on SAR images, were also discussed. Observations showed that mountain lee waves are stationary waves and have a typical wavelength of 10 km, ranging from 2-3 to 40-45 km, and a vertical amplitude of the same order of height as the mountain generating them [Gossard and Hooke, 1975; Panchev, 1985]. Lee waves, which are analogous to mountain lee waves but caused by an isolated linear island, have recently been observed by Vachon et al. [1994] using a European Remote Sensing Satellite (ERS-1) synthetic aperture radar (SAR) image. They found that a packet of six atmospheric lee waves with a wavelength of 7.6 km occurred on the lee side of the island Hopen in the Barents Sea, which is located near 76.5øN, 25.0øE, southeast of Svalbard, Norway. From another ERS-1 SAR image a nonlinear wave disturbance with an average wavelength of 2.3 km was identified in the marine atmosphere 30 km offshore in the German Bight of the North Sea by Alpers and Stilke [1996]. In this study we will investigate another kind of lee waves, which is different from the above mentioned ones. The waves were observed on ERS-1 SAR images 7979 7980 ZHENG ET AL.: COASTAL LEE WAVES ON ERS-1 SAR IMAGES of the Taiwan Strait and characterized by their occurrence being associated with the coastal environment, i.e., the transition region between marine and terrigenous air masses. The waves occurred in the form of wave packets along the lee side of the coast. The wave crest lines were nearly parallel to the coastline and reached 80 km long. According to this close association of its occurrence with the coast, a unique feature, we define this kind of lee wave as a coastal lee wave.
Http Dx Doi Org 10 2112 Jcoastres D 11 00176 1, 2012
Huang, J. and Klemas, V., 2012. Using remote sensing of land cover change in coastal watersheds t... more Huang, J. and Klemas, V., 2012. Using remote sensing of land cover change in coastal watersheds to predict downstream water quality. Journal of Coastal Research, 28(4), 930-944. West Palm Beach (Florida), ISSN 0749-0208.
Satellite remote sensors cannot see far beneath the surface layers of the ocean. Yet many importa... more Satellite remote sensors cannot see far beneath the surface layers of the ocean. Yet many important ocean processes and features are located well below the surface and at considerable depths. Examples include Mediterranean Eddies (meddies), mixed layer depth, internal waves, and bottom topography. Deeper ocean remote sensing is becoming even more important because recent data seem to indicate that the deeper ocean is responding to climate variability and change. Many of these subsurface phenomena have surface manifestations which can be interpreted with the help of models to derive key parameters of deeper ocean processes. The objective of this paper is to provide an overview of satellite remote sensing and modeling techniques which enable scientists to characterize subsurface and deeper ocean processes and features and to present some new results.
Radiance measurements using a hand-held radiometer configured to match LANDSAT TM bands 3-5 were ... more Radiance measurements using a hand-held radiometer configured to match LANDSAT TM bands 3-5 were compiled from Spartina ang/ica plots in five geographically separate marshes in Brittany, France. Aboveground biomass of the plots was harvested following the determination of radiance. Simple regression models employing a vegetation index to predict S. anglica leaf, live and total aboveground biomass from spectral radiance values were derived from data collected in one of the marshes. Radiance measurements gathered in the other four marshes (test marshes) were substituted into the biomass estimation models. In three of the test marshes, the mean model-predicted leaf and live biomass were within 1-13 per cent of the harvest values. In the other test marsh, dead material located near the top of the canopy caused biomass to be underestimated. Total (live and dead) biomass predictions were not close to harvest values in any of the marshes. This study demonstrated that a simple regression equation relating radiance data (in the form of a vegetation index) to S. ang/ica biomass in one marsh can be employed to accurately predict leaf and live S. ang/ica biomass in other, distant, marshes.
ABSTRACT Abstract With the coastal population increasing, storms have been inflicting unprecedent... more ABSTRACT Abstract With the coastal population increasing, storms have been inflicting unprecedented losses to coastal communities. Coastal agencies require advance information on the predicted path, intensity and progress of a storm and associated waves and storm surges, near-real-time information during the peak of the storm to monitor flooding and control rescue operations, and post-storm reports to assess the damage and plan and implement the recovery. The same holds true for other disasters, such as oil spills and algal blooms. Coastal communities are also facing a rising sea level, caused mainly by global warming. Airborne and satellite remote sensors, such as multispectral imagers, Lidar and radar, are now able to provide most of the information required for emergency response and coastal management.
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Papers by Victor Klemas