Kelp forests provide key habitat on the Pacific Coast of Canada; however, the long-term changes in their distribution and abundance remain poorly understood. With advances in satellite technology, floating kelp forests can now be... more
Kelp forests provide key habitat on the Pacific Coast of Canada; however, the long-term changes in their distribution and abundance remain poorly understood. With advances in satellite technology, floating kelp forests can now be monitored across large-scale areas. We present a methodological framework using an object-based image analysis approach that enables the combination of imagery from multiple satellites at different spatial resolutions and temporal coverage, to map kelp forests with floating canopy through time. The framework comprises four steps: (1) compilation and quality assessment; (2) preprocessing; (3) an object-oriented classification; and (4) an accuracy assessment. Additionally, the impact of spatial resolution on the detectability of floating kelp forests is described. Overall, this workflow was successful in producing accurate maps of floating kelp forests, with global accuracy scores of between 88% and 94%. When comparing the impact of resolution on detectabilit...
Research Interests:
Research Interests:
Research Interests:
In the Salish Sea, eelgrass meadows provide structurally complex habitat for a myriad of fish and invertebrate species, supporting marine ecosystems and stabilizing coastal sediments. Seagrasses of all species however, are in worldwide... more
In the Salish Sea, eelgrass meadows provide structurally complex habitat for a myriad of fish and invertebrate species, supporting marine ecosystems and stabilizing coastal sediments. Seagrasses of all species however, are in worldwide decline as increasing coastal development threatens the function and diversity of nearshore marine ecosystems. Long-term studies of the spatio-temporal dynamics of eelgrass in the Salish Sea are an important step in identifying contributing factors to eelgrass decline, and developing effective conservation and restoration strategies. One such dynamic to quantify are the impacts of coastal development on the distribution and trends of eelgrass ecosystems. Utilizing a historic aerial photography dataset covering the Southern Gulf Islands, BC over the years of 1932 to 2014, eelgrass beds were mapped using digital image classification methods for selected sites within the region. Through the application of a GIS change analysis, trends in eelgrass distribution were characterized and compared to changes in shoreline development and land use change in adjacent catchment areas. The results of this analysis can be applied to education, conservation, and restoration practices to prevent further eelgrass decline in the Salish Sea and beyond
Research Interests:
Research Interests:
Synthetic aperture radar images, combined with field measurements, were used to estimate net primary productivity (NPP) of aquatic vegetation in the lower Amazon. Input data for a NPP model are (i) the total biomass of aquatic vegetation,... more
Synthetic aperture radar images, combined with field measurements, were used to estimate net primary productivity (NPP) of aquatic vegetation in the lower Amazon. Input data for a NPP model are (i) the total biomass of aquatic vegetation, determined by radar imagery and field measurements and (ii) the area occupied by aquatic vegetation, determined from radar imagery. After correction for monthly biomass losses, the NPP of one growth cycle of aquatic vegetation was calculated in the image domain. The total net primary productivity of Hymenachne amplexicaules, the dominant aquatic vegetation in the area, was on average 19×10 g C yr for the entire area. Spatially, lower values of produced organic carbon (<900 g C m yr) are confined to regions where the plants developed only in the beginning of the rising phase of the hydrological cycle. In general, values are higher (>5000 g C m yr) in areas closer to the Amazon River where the availability and influence of nutrient‐rich water is greater.
Research Interests: Environmental Science, Remote Sensing, Hydrology, Biomass, Productivity, and 15 moreGrowth, Models, Synthetic Aperture Radar, Geomatic Engineering, Floodplain, Nutrients, Aquatic Vegetation, Floodplains, Vegetation, Primary Production, Amazon rainforest, Availability, Primary productivity, Organic carbon, and Cycle
Japanese Earth Resources Satellite 1 (JERS-1) imagery acquired over the Amazon basin during low- and high-water periods makes it possible to map seasonal inundation and vegetation of wetlands for most of the basin. Dual-season mapping has... more
Japanese Earth Resources Satellite 1 (JERS-1) imagery acquired over the Amazon basin during low- and high-water periods makes it possible to map seasonal inundation and vegetation of wetlands for most of the basin. Dual-season mapping has now been completed for a central Amazon quadrat extending from 72\deg W,0\deg S to 54\deg W,8\deg S. Imagery was acquired by the JERS-1 L-band, HH-polarized SAR during Sept.-Oct. 1995 and May-June 1996, and mosaicked at the Jet Propulsion Laboratory into low- and high-water mosaics with pixel dimensions of approx. 100 m. Image segmentation software developed at INPE was used to carry out a polygon-based classification of the co-registered mosaics into wetland and non-wetland classes. Wetland areas were classified by inundation state (flooded vs. non-flooded) and vegetation type (non-vegetated, woody, or herbaceous), and classification accuracy was assessed using geo-coded digital videography acquired during aerial surveys of the Brazilian Amazon. Seventeen percent of the study quadrat is occupied by wetlands, which are 96% inundated at high water and 26% inundated at low water (including river and stream channels). Flooded forest constitutes nearly 70% of the wetland area at high water. This mapping methodology is being applied to the entire lowland portion of the basin. In order to map inundation extent at intermediate water stages, and to increase classification accuracy in savanna regions, we are using time series of high-resolution JERS-1 and Radarsat data, and will make extensive use of planned acquisitions from the ENVISAT ASAR and ALOS PALSAR sensors.
Research Interests:
Research Interests:
Field measurements were combined with Synthetic Aperture Radar (SAR) images to evaluate the use of radar for estimating biomass changes and mapping of aquatic vegetation in the lower Amazon. Field campaigns were conducted concomitant to... more
Field measurements were combined with Synthetic Aperture Radar (SAR) images to evaluate the use of radar for estimating biomass changes and mapping of aquatic vegetation in the lower Amazon. Field campaigns were conducted concomitant to the acquisition of Radarsat and JERS-1 images at five different stages of the hydrological cycle. The temporal variability of the SAR data for aquatic vegetation shows a dynamic range of 5 dB, however this is due dominantly to the significant differences ( p <0.05) between the low water season when vegetation is small and just emerging and other seasons when vegetation is fully developed. The spatial variability of the above-water biomass is detectable with radar data. Significant correlation ( p <0.05) exist between backscattering coefficients and both above-water dry biomass and height of the plants. The logarithmic relationship between backscattering coefficients and biomass suggests that (1) at low biomass, high transmissivity of the microwave radiation through the vegetation canopy occurs and the backscattering is a result of quasi-specular reflection of both C and L bands and a minor contribution of canopy volume scattering from C band; (2) at intermediate levels of biomass, moderate changes in backscattering values occur and the saturation point of backscattering is reached; and (3) at high biomass, the transmissivity of C and L band radiation is equally attenuated and backscattering approaches similar values for both. A combination of Radarsat and JERS-1 images from high and low water periods were classified using a segmentation algorithm and had an accuracy higher than 97% for vegetated areas of the floodplain. Although further research is needed to better understand the saturation points for Radarsat and JERS-1 data, these findings clearly show that C and L bands can accurately map aquatic vegetation of the Amazon floodplain.
Research Interests:
Page 1. 560 IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING, VOL. 3, NO. 4, DECEMBER 2010 Using ALOS/PALSAR and RADARSAT-2 to Map Land Cover and Seasonal Inundation in the Brazilian Pantanal ...
Research Interests: Geography, Computer Science, Human Development, Biology, Remote Sensing (Earth Sciences), and 13 moreBiodiversity, Habitat Mapping, Seasonality, Land Cover, Wetland, Habitat, Synthetic Aperture Radar, Aquatic Vegetation, Threatened Species, Object Based Image Analysis, Level, Interannual Variability, and Radar Imaging
Research Interests:
Herbaceous aquatic macrophytes cover extensive areas on the floodplains of the Amazon basin and are an important habitat and input of organic carbon. These communities have large intra- and inter-annual variability, and characterization... more
Herbaceous aquatic macrophytes cover extensive areas on the floodplains of the Amazon basin and are an important habitat and input of organic carbon. These communities have large intra- and inter-annual variability, and characterization of this variability is necessary to quantify the role of macrophytes in the ecology and biogeochemistry of the floodplain. A novel approach for mapping the temporal evolution
Research Interests: Environmental Science, Remote Sensing, Climate Change, Carbon Cycle, Seasonality, and 14 moreAquatic Macrophytes, Geomatic Engineering, Floodplain, Aquatic Vegetation, Spatial Variability, Object oriented classification, Amazon rainforest, Organic carbon, Amazon basin, Macrophyte, Hierarchical Classification, Temporal Variability, Plant Distribution, and Temporal Change
Research Interests: Geography, Environmental Science, Biomass, Aquatic botany, Macrophytes, and 15 moreAllometry, Aquatic Plant, Aquatic Macrophytes, Estimation, Floodplain, Aquatic Vegetation, Accuracy, Amazon rainforest, Allometric, Dry Mass, Estimation Method, Direct Method, ENVIRONMENTAL SCIENCE AND MANAGEMENT, Flood plain, and Model performance
Research Interests:
Research Interests:
Research Interests:
RADARSAT S1 and S7, and JERS imagery are integrated with field measurements of geochemistry and characteristics of emergent aquatic vegetation to investigate the potential of SAR data to map fresh and brackish lakes of the Brazilian... more
RADARSAT S1 and S7, and JERS imagery are integrated with field measurements of geochemistry and characteristics of emergent aquatic vegetation to investigate the potential of SAR data to map fresh and brackish lakes of the Brazilian Pantanal. SAR images can determine emergent aquatic plant assemblages which are controlled by the total dissolved solids and pH of lakes. SAR images can therefore potentially be used to indirectly map the geochemistry of the hundreds of thousands of lakes in the Pantanal. This may be the most feasible way to map lake type in the Pantanal because the area is remote and the lakes are so numerous. The quantities and types of lakes and their spatial distribution is important information for understanding how the Pantanal ecosystem formed, how it works, and what is required to preserve it.
Research Interests:
ABSTRACT Nahirnick, N.K.; Costa, M.; Schroeder, S., and Sharma, T., 2020. Long-term eelgrass habitat change and associated human impacts on the west coast of Canada. Journal of Coastal Research, 36(1), 30–40. Coconut Creek (Florida), ISSN... more
ABSTRACT Nahirnick, N.K.; Costa, M.; Schroeder, S., and Sharma, T., 2020. Long-term eelgrass habitat change and associated human impacts on the west coast of Canada. Journal of Coastal Research, 36(1), 30–40. Coconut Creek (Florida), ISSN 0749-0208. Eelgrass (Zostera marina) forms a critical nearshore marine habitat in temperate coastal ecosystems. For three small estuaries in the Southern Gulf Islands of British Columbia, changes in eelgrass area coverage and shape index (over the period of 1932–2016) were assessed using historical aerial photographs and unoccupied aerial system (UAS) imagery. In addition, changes in eelgrass area and shape index were evaluated in relation to landscape-level coastal environmental indicators, namely shoreline activities and alterations and residential housing density. All three eelgrass meadows showed a deteriorating trend in eelgrass condition; on average, eelgrass area coverage decreased by 45.1%, while meadow complexity as indicated by the shape index increased by 66.3%. Shoreline activities (boats, docks, log booms, and armoring) and residential housing density increased markedly at all sites over the study period and were strongly correlated to eelgrass area coverage and shape index. Changes in these landscape-level indicators over this period corroborate the observed decline in eelgrass habitat condition, because they suggest an overall deterioration of coastal environmental health in the Salish Sea due to increased use of the coastal zone, as well as declines in water quality due to urbanization.
Research Interests: Engineering, Geography, Earth Sciences, Oceanography, Seagrass, and 4 moreCoastal, Habitat, Fishery, and Zostera Marina
The subarctic northeast Pacific (SNEP) is a high-nitrate, low-chlorophyll (HNLC) region in the ocean, where phytoplankton growth and productivity are limited by iron. Moreover, there is a limited application of high spatial (300 m) and... more
The subarctic northeast Pacific (SNEP) is a high-nitrate, low-chlorophyll (HNLC) region in the ocean, where phytoplankton growth and productivity are limited by iron. Moreover, there is a limited application of high spatial (300 m) and temporal resolution (daily) ocean color (OC) satellite imagery in studying the phytoplankton dynamics in this region. To address this issue, we aim to validate the remote sensing reflectance (Rrs; sr−1(λ)) and chlorophyll-a (Chla) concentration derived from the Polymer atmospheric correction algorithm against in situ data for the SNEP obtained during 2019 and 2020. Additionally, we performed qualitative analysis using weekly binned surface Chla maps to determine whether the product reflects the general pattern over a latitudinal and longitudinal domain. We processed the daily Level-1 image using Polymer and binned them weekly using Graphic Processing Tool (GPT). The validation results indicate that Polymer exhibits higher radiometric performance in th...
Research Interests:
Research Interests:
Kelp forests are among the most abundant coastal marine habitats but are vulnerable to the impacts of climate change. Between 2014 and 2016, an unprecedented heatwave and associated changes in trophic dynamics threatened kelp forests... more
Kelp forests are among the most abundant coastal marine habitats but are vulnerable to the impacts of climate change. Between 2014 and 2016, an unprecedented heatwave and associated changes in trophic dynamics threatened kelp forests across the Northeast Pacific, with impacts documented from Mexico to Alaska. However, responses have varied substantially and remain poorly characterized across large stretches of coast, especially British Columbia (B.C.), which represents a significant percentage of the range of floating kelp species in the Northeast Pacific. Here, we explore variation in floating kelp (Macrocystis, Nereocystis) persistence pre- and post-heatwave across a >675 km latitudinal gradient, asking whether B.C. kelp forests are of conservation concern. We assembled and analyzed available quantitative kelp data, comparing snapshots of kelp extent before (1994 - 2007) and after (2018 - 2021) the heatwave in 11 regions spanning a range of temperature and sea otter occupancy s...
Research Interests:
The planktonic diversity throughout the oceans is vital to ecosystem functioning and linked to environmental change. Plankton monitoring tools have advanced considerably with high-throughput in-situ digital cameras and genomic sequencing,... more
The planktonic diversity throughout the oceans is vital to ecosystem functioning and linked to environmental change. Plankton monitoring tools have advanced considerably with high-throughput in-situ digital cameras and genomic sequencing, opening new challenges for high-frequency observations of community composition, structure, and species discovery. Here, we combine multi-marker metabarcoding based on nuclear 18S (V4) and plastidial 16S (V4–V5) rRNA gene amplicons with a digital in-line holographic microscope to provide a synoptic diversity survey of eukaryotic plankton along the Newfoundland Shelf (Canada) during the winter transition phase of the North Atlantic bloom phenomenon. Metabarcoding revealed a rich eukaryotic diversity unidentifiable in the imaging samples, confirming the presence of ecologically important saprophytic protists which were unclassifiable in matching images, and detecting important groups unobserved or taxonomically unresolved during similar sequencing ca...
Research Interests:
The validation of ocean color satellite retrievals generally relies on analyzing match-ups between in situ measurements and satellite retrievals. These analyses focus on the quality of the satellite data, however, of the same importance... more
The validation of ocean color satellite retrievals generally relies on analyzing match-ups between in situ measurements and satellite retrievals. These analyses focus on the quality of the satellite data, however, of the same importance is the quality of the in situ data. Here, we present the spatial variability of in situ above-water reflectance (Rrs(0+)) within the spatial resolution of different ocean color satellites—300, 900, 1500, and 3000 m spatial resolutions, mimicking Sentinel 3 OLCI and MODIS-Aqua satellites, and possible 3 × 3 and 5 × 5 windows. Radiometric data was acquired with autonomous radiometric sensors installed in the British Columbia Ferry Services Inc. vessel “Queen of Alberni” from May to September 2019, crossing the optically dynamic waters of the Strait of Georgia, Canada. The dataset followed optimal geometry of acquisition and processing, including corrections for skylight radiance signals, ship superstructure, the non-isotropic distribution of the water-...
Research Interests:
Research Interests:
In the Salish Sea, eelgrass meadows provide structurally complex habitat for a myriad of fish and invertebrate species, supporting marine ecosystems and stabilizing coastal sediments. Seagrasses of all species however, are in worldwide... more
In the Salish Sea, eelgrass meadows provide structurally complex habitat for a myriad of fish and invertebrate species, supporting marine ecosystems and stabilizing coastal sediments. Seagrasses of all species however, are in worldwide decline as increasing coastal development threatens the function and diversity of nearshore marine ecosystems. Long-term studies of the spatio-temporal dynamics of eelgrass in the Salish Sea are an important step in identifying contributing factors to eelgrass decline, and developing effective conservation and restoration strategies. One such dynamic to quantify are the impacts of coastal development on the distribution and trends of eelgrass ecosystems. Utilizing a historic aerial photography dataset covering the Southern Gulf Islands, BC over the years of 1932 to 2014, eelgrass beds were mapped using digital image classification methods for selected sites within the region. Through the application of a GIS change analysis, trends in eelgrass distribution were characterized and compared to changes in shoreline development and land use change in adjacent catchment areas. The results of this analysis can be applied to education, conservation, and restoration practices to prevent further eelgrass decline in the Salish Sea and beyond
Research Interests:
Research Interests:
This paper introduces MAPSAR (Multi-Application Purpose SAR): a new SAR (Synthetic Aperture Radar) mission for Earth Observation. MAPSAR is the result of a joint pre-phase A study made by INPE and DLR targeting a mission with a small... more
This paper introduces MAPSAR (Multi-Application Purpose SAR): a new SAR (Synthetic Aperture Radar) mission for Earth Observation. MAPSAR is the result of a joint pre-phase A study made by INPE and DLR targeting a mission with a small spaceborne SAR for day and night Earth surface observation independent of weather conditions for assessment, management and monitoring natural (renewable and non-renewable) resources. In the study, the applicability of the sensor system to the following themes was investigated: Cartography, Forestry, Geology, Geomorphology, Hydrology, Agriculture, Disaster Management, Oceanography and Urban Studies. To accomplish the overall requirements, an L-band SAR has been chosen as the only payload of a small satellite. The satellite, based on the INPEs Multi Mission Platform, (MMP) is presented as well. The modular system consists of the satellite bus (platform) and a payload module for the SAR sensor accommodation. A dawn/dusk sun-synchronous orbit with a repeat...
Research Interests:
This data set reports measurements of aquatic macrophyte biomass, phenology, leaf characteristics, and length and diameter of stems of both submerged and unsubmerged macrophytes. Data were collected from sites in the Monte Alegre Lake... more
This data set reports measurements of aquatic macrophyte biomass, phenology, leaf characteristics, and length and diameter of stems of both submerged and unsubmerged macrophytes. Data were collected from sites in the Monte Alegre Lake region on the eastern Amazon River floodplain in Para, Brazil. Ten field surveys were made at approximately monthly intervals from December 2003 to November 2004. There is one comma-delimited data file with this data set.
Research Interests:
Ocean colour remote sensing is a useful tool for monitoring marine ecosystem health through the detection of chlorophyll-a, a proxy for phytoplankton biomass. Phytoplankton are important to marine ecosystems as the base of the aquatic... more
Ocean colour remote sensing is a useful tool for monitoring marine ecosystem health through the detection of chlorophyll-a, a proxy for phytoplankton biomass. Phytoplankton are important to marine ecosystems as the base of the aquatic food web. The year 2015 displayed anomalously high chlorophyll-a concentrations in the Salish Sea. Utilizing the Moderate Resolution Imaging Spectroradiometer (MODIS-Aqua) ocean colour satellite (1000m resolution), chlorophyll-a was characterized for 2015. The imagery was processed in order to correct for atmospheric contribution to the signal using a method developed specifically for the Salish Sea. Individual pixels were flagged in order to screen out incorrect or unusable elements, such as those where chlorophyll-a concentrations are overestimated (deemed above 60 mg/m3), the area is obscured by cloud, or the atmospheric correction has failed. Compared to previous years, 2015 displayed uncharacteristically few pixels with chlorophyll-a estimates in the Salish Sea, likely due to the the flagging threshold unaccustomed to such wide scale high chlorophyll-a concentrations, resulting in faulty loss of data. To account for these flagged pixels, MODIS-Aqua imagery from 2015 of the Salish Sea was reprocessed with revised thresholds for the applied flags. The satellite chlorophyll-a measurements were evaluated in relation to in situ chlorophyll-a data collected by the Ocean Networks Canada (ONC) FerryBox project, citizen science chlorophyll-a data facilitated by the Pacific Salmon Foundation, and chlorophyll-a concentrations collected by DFO. Revising the thresholds and encorportaing in situ data will result in more pixels with chlorophyll-a for analysis
Research Interests:
This study defined procedures for the use of satellite optical imagery, specifically WorldView-2 and SPOT 6, to map the canopy distribution of kelp Nereocystis leutkeana. The most accurate kelp map product attained was produced from the... more
This study defined procedures for the use of satellite optical imagery, specifically WorldView-2 and SPOT 6, to map the canopy distribution of kelp Nereocystis leutkeana. The most accurate kelp map product attained was produced from the SPOT-6 image, with the selected variable set of principle component PC2 and PC3 after image preprocessing steps of georectification, atmospheric correction, masking of land and depth below 30 m, and the statistical image processing steps of principle components analysis and variable reduction. The comparison of the satellite derived kelp map with the in situ kelp survey showed the high effectiveness of the developed procedures. It is important to highlight the difficultly in comparing satellite derived kelp maps with in situ survey data given (1) the mobility of kelp beds at the surface with changing water depth and current direction throughout tidal cycles; (2) the fast growth rate of Nereocystis rapidly changing the standing crop of kelp between the time of image acquisition and the time of kelp survey; (3) locational error intrinsic in field surveys due to occasional human error, the accuracy level of the GPS
Research Interests:
Having and maintaining suitable water quality is critical to sustain life on our planet. Monitoring of water quality using remote sensing, in conjunction with strategic in situ sampling can play a crucial role in determining the current... more
Having and maintaining suitable water quality is critical to sustain life on our planet. Monitoring of water quality using remote sensing, in conjunction with strategic in situ sampling can play a crucial role in determining the current status of water quality conditions and helps anticipate, mitigate and even avoid future water catastrophes. The GEO Remote Sensing of Water Quality Workshop helped identify issues, gaps, solutions and recommendations to expand our capability and capacity to utilize remote sensing technology. A major outcome of the workshop was a series of recommendations, addressing a number of far-ranging facets of this emerging remote sensing application. Key recommendations focused on continuity of existing satellites, development of new and improved sensor/platform technology, algorithm development and calibration/validation activities, improvements in data accessibility, education, and capacity building through new demonstration project initiatives, and the form...
Research Interests:
O objetivo deste relatorio e o de apresentar as atividades realizadas no contexto da cooperacao INPE-CCRS na area teste do reservatorio de Tucurui. O capitulo 2 apresenta uma descricao da area de estudo, no capitulo 3 e apresentado um... more
O objetivo deste relatorio e o de apresentar as atividades realizadas no contexto da cooperacao INPE-CCRS na area teste do reservatorio de Tucurui. O capitulo 2 apresenta uma descricao da area de estudo, no capitulo 3 e apresentado um resumo da Missao SAREX 92 em Tucurui, no capitulo 4 e apresentada uma breve revisao bibliografica sobre a aplicacao de dados de radar no estudo de ambientes aquaticos e regioes alagadas, no capitulo 5 e feita uma descricao da metodologia e no capitulo 6 sao apresentados os resultados preliminares do projeto. Number of Pages: 64
Research Interests:
The Brazilian Pantanal is a large continuous tropical wetland with large biodiversity and many threatened habitats. The interplay between the distribution of vegetation, the hydrology, the climate and the geomorphology nourishes and... more
The Brazilian Pantanal is a large continuous tropical wetland with large biodiversity and many threatened habitats. The interplay between the distribution of vegetation, the hydrology, the climate and the geomorphology nourishes and sustains the large diversity of flora and fauna in this wetland, but it is poorly understood at the scale of the entire Pantanal. This study uses multi-temporal L-band ALOS/PALSAR and C-band RADARSAT-2 and ENVISAT/ASAR data to map ecosystems and create a lake distribution map of the Nhecolandia region in the Brazilian Pantanal. A Level 1 object-based image analysis (OBIA) classification defining fresh and brackish lakes was achieved with accuracy results of 98%. A Level 2 classification separating two types of fresh lakes and brackish lakes achieved with accuracy results of 81%. The preliminary analysis of distribution of lakes in relationship to the marsh deer distribution showed that d7uring the dry season, the the marsh deer are in close proximity to ...
Monitoring the spatial distribution and seasonal dynamics of phytoplankton functional types (PFTs) in coastal oceans is essential for understanding fisheries production, changes in water quality, and carbon export to the deep ocean. The... more
Monitoring the spatial distribution and seasonal dynamics of phytoplankton functional types (PFTs) in coastal oceans is essential for understanding fisheries production, changes in water quality, and carbon export to the deep ocean. The launch of new generation ocean color sensors such as OLCI (Ocean Land Color Instrument) onboard Sentinel 3A provides an unprecedented opportunity to study the surface dynamics of PFTs at high spatial (300 m) and temporal (daily) resolution. Here we characterize the seasonal dynamics of the major PFTs over the surface waters of the west coast of Canada using OLCI imagery and Chemical Taxonomy (CHEMTAX, v1.95) software. The satellite-based approach was adapted from a previously proven Empirical Orthogonal Function (EOF)-based algorithm by using a local matchup dataset comprising CHEMTAX model output and EOF scores derived from OLCI remote sensing reflectance. The algorithm was developed for the following PFTs: diatoms, dinoflagellates, dictyochophytes,...
The Strait of Georgia, Canada, is an important region for numerous commercially and culturally important species (e.g., herring, salmon, and orcas), yet little is known about the links between lower trophic level (e.g. phytoplankton and... more
The Strait of Georgia, Canada, is an important region for numerous commercially and culturally important species (e.g., herring, salmon, and orcas), yet little is known about the links between lower trophic level (e.g. phytoplankton and zooplankton) phenology due to historical sampling gaps. Here, we present fourteen years (2003-2016) of data linking interannual variability in phytoplankton and zooplankton phenology in the Central Strait of Georgia, BC. Satellite-derived chlorophyll a (Chl a) data were used to calculate spring bloom dynamics (bloom initiation, bloom intensity, and bloom magnitude). Average spring bloom initiation occurred during the last week of March in the Central Strait of Georgia. Bloom initiation occurred in mid-to-late February/early March during “early” Chl a bloom years (2004, 2005, and 2015) whereas initiation did not occur until the end of April during “late” bloom years (2007, 2008). Spring Chl a bloom initiation was significantly correlated with the Nort...
Research Interests:
Eelgrass (Zostera marina) is a critical nearshore marine habitat for juvenile Pacific salmon (Oncorhynchus spp.) as they depart from their natal streams. Given the poor marine survival of Coho (O. kisutch) and Chinook (O. tshawytscha)... more
Eelgrass (Zostera marina) is a critical nearshore marine habitat for juvenile Pacific salmon (Oncorhynchus spp.) as they depart from their natal streams. Given the poor marine survival of Coho (O. kisutch) and Chinook (O. tshawytscha) salmon juveniles in recent decades, it is hypothesized that deteriorating eelgrass habitats could contribute to their low survival. The primary goal of this research was to investigate the possible long-term spatial-temporal trends in eelgrass habitat in the Salish Sea and was addressed by two main objectives: (1) Define a methodology for mapping eelgrass habitats using UAV imagery to create a baseline for long-term mapping; and (2) Assess changes in eelgrass area coverage and fragmentation over the period of 1932-2016 using historic aerial photographs and Unmanned Aerial Vehicle (UAV) imagery, and assess the relationship between eelgrass and residential housing density and shoreline activities. Three study sites in the Southern Gulf Islands of the Sal...
Research Interests:
Many Earth observing sensors have been designed, built and launched with primary objectives of either terrestrial or ocean remote sensing applications. Often the data from these sensors are also used for freshwater, estuarine and coastal... more
Many Earth observing sensors have been designed, built and launched with primary objectives of either terrestrial or ocean remote sensing applications. Often the data from these sensors are also used for freshwater, estuarine and coastal water quality observations and bathymetry and benthic mapping. However, such land and ocean specific sensors are not designed for these complex aquatic environments and consequently are not likely to perform as well as a dedicated sensor would. As a CEOS action, CSIRO and DLR have taken the lead on a feasibility assessment to determine the benefits and technological difficulties of designing an Earth observing satellite mission focused on the biogeochemistry of inland, estuarine, deltaic and near coastal waters as well as mapping macrophytes, macro-algae, sea grasses and coral reefs. These environments need higher spatial resolution than current and planned ocean colour sensors offer and need higher spectral resolution than current and planned land ...
Research Interests:
Kelp forests are commonly classified within remote sensing imagery by contrasting the high reflectance in the near-infrared spectral region of kelp canopy floating at the surface with the low reflectance in the same spectral region of... more
Kelp forests are commonly classified within remote sensing imagery by contrasting the high reflectance in the near-infrared spectral region of kelp canopy floating at the surface with the low reflectance in the same spectral region of water. However, kelp canopy is often submerged below the surface of the water, making it important to understand the effects of kelp submersion on the above-water reflectance of kelp, and the depth to which kelp can be detected, in order to reduce uncertainties around the kelp canopy area when mapping kelp. Here, we characterized changes to the above-water spectra of Nereocystis luetkeana (Bull kelp) as different canopy structures (bulb and blades) were submerged in water from the surface to 100 cm in 10 cm increments, while collecting above-water hyperspectral measurements with a spectroradiometer (325–1075 nm). The hyperspectral data were simulated into the multispectral bandwidths of the WorldView-3 satellite and the Micasense RedEdge-MX unoccupied ...
Research Interests:
Spatial data layers on: (1) the administrative boundaries for (a) barangays, (b) municipalities, and (c) municipal waters in the study region in Sogod Bay, Philippines; (2) the distribution of coastal habitats derived from a remote... more
Spatial data layers on: (1) the administrative boundaries for (a) barangays, (b) municipalities, and (c) municipal waters in the study region in Sogod Bay, Philippines; (2) the distribution of coastal habitats derived from a remote sensing analysis using WorldView-2 images and underwater video transects; and (3) the location of (a) current marine protected areas (MPAs) and (b) prospective MPA sites identified and supported by coastal communities, (c) new MPAs identified through a national-scale and donor-assisted conservation project that utilized local knowledge to select MPAs, and (d) new MPA sites selected through a systematic conservation planning approach that employed the spatial prioritization software 'Marxan with Zones' to achieve biodiversity objectives with minimal and equitable costs to fisher stakeholder groups. This dataset was used to investigate alternative planning options for designing a MPA network in Sogod Bay in Southern Leyte province in the Philippines...
Many Earth observing sensors have been designed, built and launched with primary objectives of either terrestrial or ocean remote sensing applications. Often the data from these sensors are also used for freshwater, estuarine and coastal... more
Many Earth observing sensors have been designed, built and launched with primary objectives of either terrestrial or ocean remote sensing applications. Often the data from these sensors are also used for freshwater, estuarine and coastal water quality observations, bathymetry and benthic mapping. However, such land and ocean specific sensors are not designed for these complex aquatic environments and consequently are not likely to perform as well as a dedicated sensor would. As a CEOS action, CSIRO and DLR have taken the lead on a feasibility assessment to determine the benefits and technological difficulties of designing an Earth observing satellite mission focused on the biogeochemistry of inland, estuarine, deltaic and near coastal waters as well as mapping macrophytes, macro-algae, sea grasses and coral reefs. These environments need higher spatial resolution than current and planned ocean colour sensors offer and need higher spectral resolution than current and planned land Ear...
Research Interests:
Surface-canopy forming kelps provide the foundation for ecosystems that are ecologically, culturally, and economically important. However, these kelp forests are naturally dynamic systems that are also threatened by a range of global and... more
Surface-canopy forming kelps provide the foundation for ecosystems that are ecologically, culturally, and economically important. However, these kelp forests are naturally dynamic systems that are also threatened by a range of global and local pressures. As a result, there is a need for tools that enable managers to reliably track changes in their distribution, abundance, and health in a timely manner. Remote sensing data availability has increased dramatically in recent years and this data represents a valuable tool for monitoring surface-canopy forming kelps. However, the choice of remote sensing data and analytic approach must be properly matched to management objectives and tailored to the physical and biological characteristics of the region of interest. This review identifies remote sensing datasets and analyses best suited to address different management needs and environmental settings using case studies from the west coast of North America. We highlight the importance of in...
Research Interests:
Abstract Coastal oceans play a pivotal role in fisheries production and global biogeochemical cycles, making large-scale monitoring an essential task. The advent of modern remote sensors, such as OLCI (Ocean Land Colour Instrument), on... more
Abstract Coastal oceans play a pivotal role in fisheries production and global biogeochemical cycles, making large-scale monitoring an essential task. The advent of modern remote sensors, such as OLCI (Ocean Land Colour Instrument), on board the Sentinel-3A satellite, has made it possible to obtain oceanic biogeochemical products at higher spatial (300 m) and temporal (daily) resolutions than previously possible. However, validating the Sentinel-3A retrievals for coastal waters is an ongoing effort. Using a regional in situ dataset from British Columbia (BC) and Southeast Alaska (SEA) coastal waters, we evaluated the performance of OLCI Sentinel-3A in retrieving remote-sensing reflectance (Rrs) and biophysical products, including total suspended matter (TSM), chlorophyll-a concentration (Chl-a) and coloured dissolved organic matter (CDOM). The OLCI data were processed through a spectral optimization-based algorithm (POLYMER) and a neural net-based (NN) algorithm (C2RCC), including the original (C2RCC v1) and the alternative version (altNN or v2), in which the neural network was trained with extended ranges to cope with larger dynamic range for high backscatter waters. The processors' performance was evaluated through match-up analysis using data from southern BC, as well as expected ranges and seasonal trends for northern BC and SEA. Multimetric statistical analyses demonstrated that POLYMER provided the best overall performance for TSM and Chl-a retrievals, with the Chl-a product improved by the use of the so-called “Case-2” flag. Despite the relative outperformance of POLYMER-derived products, with low systematic biases, the relative percent differences are still high (80–100%) and should be acknowledged in future analyses when using these data. CDOM, only retrieved here from NN approaches, was better estimated using the alternative version of C2RCC. The best performing approaches were used to evaluate Level-3 composites for northern BC and SEA waters. The observed spatial and seasonal trends compared favourably with those reported in the literature, including highlighting more productive areas (e.g. west coast of Vancouver Island), and the important interactions between riverine systems and adjacent coastal waters (e.g., high TSM and CDOM loads near the Skeena and Nass rivers). This study demonstrated the benefits of OLCI Sentinel-3A to investigate complex coastal ecosystems and provides a robust evaluation of OLCI performance and a framework for future observational and process-oriented studies.
Research Interests:
Field measures were combined with synthetic aperture radar (SAR) images to evaluate the use of radar for estimating temporal biomass and mapping of aquatic vegetation in the lower Amazon. A SAR-based methodology was developed for... more
Field measures were combined with synthetic aperture radar (SAR) images to evaluate the use of radar for estimating temporal biomass and mapping of aquatic vegetation in the lower Amazon. A SAR-based methodology was developed for quantification of the annual net primary productivity (NPP) of aquatic vegetation. The predictable monomodal flooding cycle of the floodplain is the primary control of the
Research Interests:
2 Instituto Nacional de Pesquisas Espaciais (INPE), Brazil Abstract-Field measurements were combined with synthetic aperture radar images to evaluate the use of RADARSAT and JERS-1 for estimating biomass changes and mapping of aquatic... more
2 Instituto Nacional de Pesquisas Espaciais (INPE), Brazil Abstract-Field measurements were combined with synthetic aperture radar images to evaluate the use of RADARSAT and JERS-1 for estimating biomass changes and mapping of aquatic vegetation, and subsequently estimating of net primary productivity of aquatic vegetation in the lower Amazon. The combination of C and L bands provides the best correlation (r =0.82) and an intermediate saturation point (620 gm -2 ) for estimating above water biomass of aquatic vegetation. A combination of RADARSAT and JERS-1 images from each water period was classified using a region growing algorithm, and yielded an accuracy higher than 95% for the seasonal vegetated areas of the floodplain. The combination of the seasonal mapped area of aquatic vegetation with the statistical SAR-algorithm for estimating above water biomass and the percentage of below water biomass yielded a total annual NPP of 1.9x10 12 g C yr -1 (±28%) for aquatic vegetation.
Research Interests:
Research Interests:
... according to their optical characteristics has been done typically with the use of radiometric quantities and apparent optical properties (AOPs) ( [Aarup et al ... The CDOM absorption coefficient was acquired by fitting a vented Pall... more
... according to their optical characteristics has been done typically with the use of radiometric quantities and apparent optical properties (AOPs) ( [Aarup et al ... The CDOM absorption coefficient was acquired by fitting a vented Pall mini-capsule 0.2 μm sterile filter on the absorptio.
Research Interests:
Abstract: Eelgrass (Zostera marina) is a keystone component of inter- and sub-tidal ecosystems. However, anthropogenic pressures have caused its populations to decline worldwide. Delineation and continuous monitoring of eelgrass... more
Abstract: Eelgrass (Zostera marina) is a keystone component of inter- and sub-tidal ecosystems. However, anthropogenic pressures have caused its populations to decline worldwide. Delineation and continuous monitoring of eelgrass distribution is an integral part of understanding these pressures and providing effective coastal ecosystem management. A proposed tool for such spatial monitoring is remote imagery, which can cost- and time-effectively cover large and inaccessible areas frequently. However, to effectively apply this technology, an understanding is required of the spectral behavior of eelgrass and its associated substrates. In this study, in situ hyperspectral measurements were used to define key spectral variables that provide the greatest spectral separation between Z. marina and associated submerged substrates. For eelgrass classification of an in situ above water reflectance dataset, the selected variables were: slope 500–530 nm, first derivatives (R‘) at 566 nm, 580 nm,...
— Lake size is a strong control on lake function and on how lakes interact with the environment. For example, lake size is strongly related to carbon burial rates in lake sediments. Lake size distribution (how many small, medium, and... more
— Lake size is a strong control on lake function and on how lakes interact with the environment. For example, lake size is strongly related to carbon burial rates in lake sediments. Lake size distribution (how many small, medium, and large lakes, occur per unit area) can be used to extrapolate lake function to landscapes at local, regional, and global scales. Lake size distribution can be parameterized as: m = log(number of lakes/unit area) / log(lake size) – b Where m less than-1 (m <-1) indicates that small lakes occupy greater area than large lakes and vice versa. A digital database describing lake size distribution and lake shape can therefore be used to investigate and estimate lake-landscape interactions at various scales but this database does not currently exist. Here the capability of high resolution ALOS PALSAR data is examined for mapping lakes across multiple study sites