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Meng Zhou - One of the best experts on this subject based on the ideXlab platform.
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Polar Front around the kerguelen islands an up to date determination and associated circulation of surface subsurface waters
Journal of Geophysical Research, 2014Co-Authors: Younghyang Park, Meng Zhou, Isabelle Durand, Elodie Kestenare, Gilles Rougier, Francesco Dovidio, Cedric Cotte, Jaehak LeeAbstract:The circulation of iron-rich shelf waters around the Kerguelen Islands plays a crucial role for a climatically important, annually recurrent phytoplankton spring bloom over the sluggish shelf region and its downstream plume area along the Antarctic circumPolar flow. However, there is a long-standing confusion about the Polar Front (PF) in the Kerguelen region due to diverse suggestions in the literature for its geographical location with an extreme difference over 10° of latitude. Based on abundant historical hydrographic data, the in situ hydrographic and current measurements during the 2011 KEOPS2 cruise, satellite chlorophyll images, and altimetry-derived surface velocity fields, we determine and validate an up-to-date location of the PF around the Kerguelen Islands. Artificial Lagrangian particle trajectories computed from altimetric velocity time series are analyzed for the possible pathways and sources of different surface/subsurface waters advected into the chlorophyll bloom area east off the islands studied during the KEOPS2 cruise. The PF location determined as the northernmost boundary of the Winter Water colder than 2°C, which is also associated with a band of strong currents, appears to be primarily controlled by topography. The PF rounds the Kerguelen Islands from the south to deflect northward along the eastern escarpment up to the northeastern corner of the Kerguelen Plateau before making its southward retroflection. It is shown that the major surface/subsurface waters found within the deep basin east of the Kerguelen Islands originate from the shelf around the Heard Island, rather than from the shallow shelf north of the Kerguelen Islands.
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physical structure of the barents sea Polar Front near storbanken in august 2007
Journal of Marine Systems, 2014Co-Authors: Selina Vage, Sunnje Linnea Basedow, Kurt S Tande, Meng ZhouAbstract:Abstract The Polar Front separating Atlantic Water (AW) and Arctic Water (ArW) is one of the most dominant meso- and large scale features in the Barents Sea. Here, the results of submeso-mesoscale (1–10 km) variability in physical fields associated with the Barents Sea Polar Front (BSPF) are reported from a high-resolution ADCP (Acoustic Doppler Current Profiler) and CTD (Conductivity–Temperature–Depth sensors) survey near Storbanken in August 2007. A surface Front separating AW and melt water with a strong salinity gradient was present, while the subsurface BSPF was characterized by a strong temperature gradient and thermohaline compensation. Isopycnal mixing leading to the formation of Polar Front Water (PFW) was observed. The dominant flow was a barotropic southeastward along-Frontal jet with two cores, coinciding with the surface Front and the BSPF. This gives new insights into the circulation at the BSPF. Small-scale variability in the hydrographic and dynamic structures was observed, which were rarely resolved in previous cruises. Such submeso–mesoscale physical processes can potentially have significant impacts on the biogeochemistry and biology in the area, indicating the importance of parametrizing the processes in future climate models.
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secondary production at the Polar Front barents sea august 2007
Journal of Marine Systems, 2014Co-Authors: Sunnje Linnea Basedow, Meng Zhou, Kurt S TandeAbstract:Abstract To investigate spatial patterns of secondary production we sampled four core hydrographical regions of the Polar Front in the Barents Sea (Arctic Water, ArW; Polar Front Water, PFW; Atlantic Water, AtW; and Melt Water, MW) by towing an undulating instrument platform along a transect crossing the Front from August 8–9, 2007. Sensors mounted on the platform provided data on the hydrography (CTD), fluorescence (Fluorometer, F) and zooplankton abundance in the size range between 0.1 and 30 mm (Laser Optical Plankton Counter, LOPC). These continuous, biophysical data with high-spatial resolution were supplemented by discrete water and zooplankton net samples at stations for sensor calibrations. After in depth quality assessments of the biophysical data, estimates were made of the vital rates based on biovolume spectrum theory. Five size groups were distinguished from the LOPC data: small (S), mainly Oithona spp. and the appendicularian Fritillaria sp.; medium (M), mainly Pseudocalanus spp. and Calanus spp. CI–CIII; large (L), mainly Calanus spp. CIV–CV; and extra large (XL and 2XL), juvenile and adult euphausids. Size groups were further divided based on transparency of organisms. Vital rates based on the biophysical in situ data in combination with biovolume spectrum theories agreed generally well with data from empirical and numerical models in the literature. ArW was characterised by subsurface maxima of chlorophyll a (chl a), and an estimated population growth of ca. 13 mg C m− 3 d− 1 for CI–CIII Calanus spp. and some older Pseudocalanus within the chl a maxima. Frontal waters were characterised by low chl a concentrations, but high abundances and production (around 1 g C m− 3 d− 1) of small copepods (Oithona spp.) and appendicularians (Fritillaria sp.). The estimated production of small-size zooplankton was an order of magnitude higher than the production of all other size groups combined, including large copepods. The high loss rates (− 166 to − 271 mg C m− 3 d− 1) of small zooplankton may contribute a substantial amount of carbon to the benthos and to pelagic predators such as young capelin. AtW was the most productive water mass, with surface chl a maxima and an estimated population growth of 134 mg C m− 3 d− 1 for small zooplankton, 3.6 mg C m− 3 d− 1 for medium-sized copepods and 0.9 mg C m− 3 d− 1 for CIV–CVI Calanus. For those Calanus spp. in the surface layer, the estimated specific mortality rates were up to − 0.35 d− 1, partly due to high predation pressure by hydrozoans and chaetognaths.
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biovolume spectrum theories applied spatial patterns of trophic levels within a mesozooplankton community at the Polar Front
Journal of Plankton Research, 2010Co-Authors: Sunnje Linnea Basedow, Kurt S Tande, Meng ZhouAbstract:Three-dimensional data on the mesoscale distribution of hydrography and mesozooplankton were collected at the Polar Front, northwestern Barents Sea, in spring 2008 (29 April–15 May) using a combination of multinet and towed instrument platform equipped with Laser Optical Plankton Counter, fluorometer and CTD. Trophic levels (TLs) within the zooplankton community (whole community and size-separated) were analysed for three consecutive periods using biovolume spectrum theory, which proved to be a powerful tool in the physically and biologically variable Frontal system. Trophic structure was highly variable in time and across the Polar Front, but was mostly related to the phytoplankton bloom (as determined by fluorescence). High TLs of 5.5 within the zooplankton community were observed outside bloom situations (mostly in Atlantic Water) and were likely due to increased omnivory of Calanus spp., which dominated the large zooplankton size group that had a lower TL (2.2) during the bloom than outside blooms (max. TL 5.6). A strong input of herbivorous barnacle nauplii (Cirripedia) into the upper layer (35 000 ind. m−3 in net samples) substantially decreased mean TL in the marginal ice zone. Differences in TL estimates based on biovolume spectrum theory and other methods (stable isotopes, lipid markers, dietary analyses) are discussed.
Kurt S Tande - One of the best experts on this subject based on the ideXlab platform.
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physical structure of the barents sea Polar Front near storbanken in august 2007
Journal of Marine Systems, 2014Co-Authors: Selina Vage, Sunnje Linnea Basedow, Kurt S Tande, Meng ZhouAbstract:Abstract The Polar Front separating Atlantic Water (AW) and Arctic Water (ArW) is one of the most dominant meso- and large scale features in the Barents Sea. Here, the results of submeso-mesoscale (1–10 km) variability in physical fields associated with the Barents Sea Polar Front (BSPF) are reported from a high-resolution ADCP (Acoustic Doppler Current Profiler) and CTD (Conductivity–Temperature–Depth sensors) survey near Storbanken in August 2007. A surface Front separating AW and melt water with a strong salinity gradient was present, while the subsurface BSPF was characterized by a strong temperature gradient and thermohaline compensation. Isopycnal mixing leading to the formation of Polar Front Water (PFW) was observed. The dominant flow was a barotropic southeastward along-Frontal jet with two cores, coinciding with the surface Front and the BSPF. This gives new insights into the circulation at the BSPF. Small-scale variability in the hydrographic and dynamic structures was observed, which were rarely resolved in previous cruises. Such submeso–mesoscale physical processes can potentially have significant impacts on the biogeochemistry and biology in the area, indicating the importance of parametrizing the processes in future climate models.
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secondary production at the Polar Front barents sea august 2007
Journal of Marine Systems, 2014Co-Authors: Sunnje Linnea Basedow, Meng Zhou, Kurt S TandeAbstract:Abstract To investigate spatial patterns of secondary production we sampled four core hydrographical regions of the Polar Front in the Barents Sea (Arctic Water, ArW; Polar Front Water, PFW; Atlantic Water, AtW; and Melt Water, MW) by towing an undulating instrument platform along a transect crossing the Front from August 8–9, 2007. Sensors mounted on the platform provided data on the hydrography (CTD), fluorescence (Fluorometer, F) and zooplankton abundance in the size range between 0.1 and 30 mm (Laser Optical Plankton Counter, LOPC). These continuous, biophysical data with high-spatial resolution were supplemented by discrete water and zooplankton net samples at stations for sensor calibrations. After in depth quality assessments of the biophysical data, estimates were made of the vital rates based on biovolume spectrum theory. Five size groups were distinguished from the LOPC data: small (S), mainly Oithona spp. and the appendicularian Fritillaria sp.; medium (M), mainly Pseudocalanus spp. and Calanus spp. CI–CIII; large (L), mainly Calanus spp. CIV–CV; and extra large (XL and 2XL), juvenile and adult euphausids. Size groups were further divided based on transparency of organisms. Vital rates based on the biophysical in situ data in combination with biovolume spectrum theories agreed generally well with data from empirical and numerical models in the literature. ArW was characterised by subsurface maxima of chlorophyll a (chl a), and an estimated population growth of ca. 13 mg C m− 3 d− 1 for CI–CIII Calanus spp. and some older Pseudocalanus within the chl a maxima. Frontal waters were characterised by low chl a concentrations, but high abundances and production (around 1 g C m− 3 d− 1) of small copepods (Oithona spp.) and appendicularians (Fritillaria sp.). The estimated production of small-size zooplankton was an order of magnitude higher than the production of all other size groups combined, including large copepods. The high loss rates (− 166 to − 271 mg C m− 3 d− 1) of small zooplankton may contribute a substantial amount of carbon to the benthos and to pelagic predators such as young capelin. AtW was the most productive water mass, with surface chl a maxima and an estimated population growth of 134 mg C m− 3 d− 1 for small zooplankton, 3.6 mg C m− 3 d− 1 for medium-sized copepods and 0.9 mg C m− 3 d− 1 for CIV–CVI Calanus. For those Calanus spp. in the surface layer, the estimated specific mortality rates were up to − 0.35 d− 1, partly due to high predation pressure by hydrozoans and chaetognaths.
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biovolume spectrum theories applied spatial patterns of trophic levels within a mesozooplankton community at the Polar Front
Journal of Plankton Research, 2010Co-Authors: Sunnje Linnea Basedow, Kurt S Tande, Meng ZhouAbstract:Three-dimensional data on the mesoscale distribution of hydrography and mesozooplankton were collected at the Polar Front, northwestern Barents Sea, in spring 2008 (29 April–15 May) using a combination of multinet and towed instrument platform equipped with Laser Optical Plankton Counter, fluorometer and CTD. Trophic levels (TLs) within the zooplankton community (whole community and size-separated) were analysed for three consecutive periods using biovolume spectrum theory, which proved to be a powerful tool in the physically and biologically variable Frontal system. Trophic structure was highly variable in time and across the Polar Front, but was mostly related to the phytoplankton bloom (as determined by fluorescence). High TLs of 5.5 within the zooplankton community were observed outside bloom situations (mostly in Atlantic Water) and were likely due to increased omnivory of Calanus spp., which dominated the large zooplankton size group that had a lower TL (2.2) during the bloom than outside blooms (max. TL 5.6). A strong input of herbivorous barnacle nauplii (Cirripedia) into the upper layer (35 000 ind. m−3 in net samples) substantially decreased mean TL in the marginal ice zone. Differences in TL estimates based on biovolume spectrum theory and other methods (stable isotopes, lipid markers, dietary analyses) are discussed.
Sunnje Linnea Basedow - One of the best experts on this subject based on the ideXlab platform.
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physical structure of the barents sea Polar Front near storbanken in august 2007
Journal of Marine Systems, 2014Co-Authors: Selina Vage, Sunnje Linnea Basedow, Kurt S Tande, Meng ZhouAbstract:Abstract The Polar Front separating Atlantic Water (AW) and Arctic Water (ArW) is one of the most dominant meso- and large scale features in the Barents Sea. Here, the results of submeso-mesoscale (1–10 km) variability in physical fields associated with the Barents Sea Polar Front (BSPF) are reported from a high-resolution ADCP (Acoustic Doppler Current Profiler) and CTD (Conductivity–Temperature–Depth sensors) survey near Storbanken in August 2007. A surface Front separating AW and melt water with a strong salinity gradient was present, while the subsurface BSPF was characterized by a strong temperature gradient and thermohaline compensation. Isopycnal mixing leading to the formation of Polar Front Water (PFW) was observed. The dominant flow was a barotropic southeastward along-Frontal jet with two cores, coinciding with the surface Front and the BSPF. This gives new insights into the circulation at the BSPF. Small-scale variability in the hydrographic and dynamic structures was observed, which were rarely resolved in previous cruises. Such submeso–mesoscale physical processes can potentially have significant impacts on the biogeochemistry and biology in the area, indicating the importance of parametrizing the processes in future climate models.
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secondary production at the Polar Front barents sea august 2007
Journal of Marine Systems, 2014Co-Authors: Sunnje Linnea Basedow, Meng Zhou, Kurt S TandeAbstract:Abstract To investigate spatial patterns of secondary production we sampled four core hydrographical regions of the Polar Front in the Barents Sea (Arctic Water, ArW; Polar Front Water, PFW; Atlantic Water, AtW; and Melt Water, MW) by towing an undulating instrument platform along a transect crossing the Front from August 8–9, 2007. Sensors mounted on the platform provided data on the hydrography (CTD), fluorescence (Fluorometer, F) and zooplankton abundance in the size range between 0.1 and 30 mm (Laser Optical Plankton Counter, LOPC). These continuous, biophysical data with high-spatial resolution were supplemented by discrete water and zooplankton net samples at stations for sensor calibrations. After in depth quality assessments of the biophysical data, estimates were made of the vital rates based on biovolume spectrum theory. Five size groups were distinguished from the LOPC data: small (S), mainly Oithona spp. and the appendicularian Fritillaria sp.; medium (M), mainly Pseudocalanus spp. and Calanus spp. CI–CIII; large (L), mainly Calanus spp. CIV–CV; and extra large (XL and 2XL), juvenile and adult euphausids. Size groups were further divided based on transparency of organisms. Vital rates based on the biophysical in situ data in combination with biovolume spectrum theories agreed generally well with data from empirical and numerical models in the literature. ArW was characterised by subsurface maxima of chlorophyll a (chl a), and an estimated population growth of ca. 13 mg C m− 3 d− 1 for CI–CIII Calanus spp. and some older Pseudocalanus within the chl a maxima. Frontal waters were characterised by low chl a concentrations, but high abundances and production (around 1 g C m− 3 d− 1) of small copepods (Oithona spp.) and appendicularians (Fritillaria sp.). The estimated production of small-size zooplankton was an order of magnitude higher than the production of all other size groups combined, including large copepods. The high loss rates (− 166 to − 271 mg C m− 3 d− 1) of small zooplankton may contribute a substantial amount of carbon to the benthos and to pelagic predators such as young capelin. AtW was the most productive water mass, with surface chl a maxima and an estimated population growth of 134 mg C m− 3 d− 1 for small zooplankton, 3.6 mg C m− 3 d− 1 for medium-sized copepods and 0.9 mg C m− 3 d− 1 for CIV–CVI Calanus. For those Calanus spp. in the surface layer, the estimated specific mortality rates were up to − 0.35 d− 1, partly due to high predation pressure by hydrozoans and chaetognaths.
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biovolume spectrum theories applied spatial patterns of trophic levels within a mesozooplankton community at the Polar Front
Journal of Plankton Research, 2010Co-Authors: Sunnje Linnea Basedow, Kurt S Tande, Meng ZhouAbstract:Three-dimensional data on the mesoscale distribution of hydrography and mesozooplankton were collected at the Polar Front, northwestern Barents Sea, in spring 2008 (29 April–15 May) using a combination of multinet and towed instrument platform equipped with Laser Optical Plankton Counter, fluorometer and CTD. Trophic levels (TLs) within the zooplankton community (whole community and size-separated) were analysed for three consecutive periods using biovolume spectrum theory, which proved to be a powerful tool in the physically and biologically variable Frontal system. Trophic structure was highly variable in time and across the Polar Front, but was mostly related to the phytoplankton bloom (as determined by fluorescence). High TLs of 5.5 within the zooplankton community were observed outside bloom situations (mostly in Atlantic Water) and were likely due to increased omnivory of Calanus spp., which dominated the large zooplankton size group that had a lower TL (2.2) during the bloom than outside blooms (max. TL 5.6). A strong input of herbivorous barnacle nauplii (Cirripedia) into the upper layer (35 000 ind. m−3 in net samples) substantially decreased mean TL in the marginal ice zone. Differences in TL estimates based on biovolume spectrum theory and other methods (stable isotopes, lipid markers, dietary analyses) are discussed.
Mark R Abbott - One of the best experts on this subject based on the ideXlab platform.
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surface chlorophyll concentrations in relation to the antarctic Polar Front seasonal and spatial patterns from satellite observations
Journal of Marine Systems, 2002Co-Authors: Keith J Moore, Mark R AbbottAbstract:Satellite ocean color data from the Sea Viewing Wide Field of View Sensor (SeaWiFS) are used to investigate phytoplankton bloom dynamics at the Antarctic Polar Front (PF). Satellite sea surface temperature (SST) data are used to map the location of the PF at weekly timescales. Elevated chlorophyll within the PF often appears as a narrow band that occupies only a portion of the SST gradient across the PF. Phytoplankton blooms within the PF occur most frequently during the month of December and are unevenly distributed within the Southern Ocean. Elevated chlorophyll concentrations at the PF are most frequently observed where the current is interacting with large topographic features. Mesoscale physical processes, including meander-induced upwelling and increased eddy mixing, where the PF encounters large topographic features likely leads to increased nutrient flux to surface waters in these regions. The highest mean chlorophyll values associated with the PF occur where the Front comes into contact with relatively shallow waters along the North Scotia Ridge and at Kerguelen Plateau. Iron input from sedimentary sources likely plays an important role in these regions. Over seasonal timescales it appears likely that light-limitation prevents phytoplankton blooms at the PF during winter and spring months. PF blooms are observed most commonly during December when surface radiation peaks and mixed layer depths are rapidly shoaling. Even during December, when the light regime would seem to be favorable, PF blooms are largely restricted to regions where enhanced nutrient fluxes to surface waters due to Frontal dynamics are likely. During late summer, nutrient limitation due to depletion of iron and possibly silicate largely prevent blooms at the PF. In the fall, deepening mixed layers would provide some relief from nutrient limitation but likely lead again to light-limitation of growth rates and the prevention of blooms. D 2002 Elsevier Science B.V. All rights reserved.
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seasonal dynamics of phytoplankton in the antarctic Polar Front region at 170 w
Deep-sea Research Part Ii-topical Studies in Oceanography, 2002Co-Authors: Michael R Landry, Mark R Abbott, Karen E Selph, Colleen B Allen, Albert Calbet, Stephanie Christensen, Susan L Brown, C I Measures, Suzanna Vink, Hector NollaAbstract:Phytoplankton dynamics in the region of 55-70degreesS, 170degreesW were investigated using Sea-viewing Wide Field-of-View Sensor satellite imagery, shipboard sampling and experimental rate assessments during austral spring and summer, 1997-1998. We used image-analysis microscopy to characterize community biomass and composition, and dilution experiments to estimate growth and microzooplankton grazing rates. Iron concentrations were determined by flow-injection analysis. The phytoplankton increase began slowly with the onset of stratification at the Polar Front (PF) (60-61degreesS) in early November. Seasonally enhanced levels of chlorophyll were found as far north as 58degreesS, but mixed-layer phytoplankton standing stock was highest, approaching 200 mg C m(-3), in the region between the receding ice edge and a strong silicate gradient, which migrated from similar to62degreesS to 65degreesS during the study period. The most southern stations sampled on four cruises were characterized by small pennate diatoms and Phaeocystis. From the PF to the Southern Antarctic circumPolar current Front (similar to65degreesS), this ice margin assemblage was seasonally replaced by a community dominated by large diatoms. The large diatom community developed only in waters where measured iron concentrations were initially high (greater than or equal to0.2 nM), and crashed when dissolved silicate was depleted to low levels. Phytoplankton growth rates were highest (0.5-0.6 d(-1)) between the PF and silicate Front (60degreesS and 63degreesS) in December. In January, growth rates were lowest (0.1 d(-1)) near the PF, and the highest rates (0.34.4 d(-1)) were found in experiments between 64.8degreesS and 67.8degreesS. Phytoplankton production estimates were highest south of the PF through December and January, averaging 2.2-2.4 mmol C m(-3) d(-1) and reaching levels of 5 mmol cm(-3) d(-1) (64.8degreesS and 67.8degreesS in January). Microzooplankton grazers consumed 54-95% of production for experiments conducted on four AESOPS cruises. They were less efficient in balancing growth rates during the time of highest phytoplankton growth and increase in December, and most efficient in February-March, after the large diatom bloom had collapsed. The diatom bloom region in the present study is in an upwelling zone for Antarctic circumPolar deep water with high iron content. This may explain why this marginal ice zone differs from others where blooms have not been observed. (C) 2002 Published by Elsevier Science Ltd.
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initiation of the spring phytoplankton increase in the antarctic Polar Front zone at 170 w
Journal of Geophysical Research, 2001Co-Authors: Michael R Landry, Mark R Abbott, Karen E Selph, Stephanie Christensen, Robert R Bidigare, Susan L Brown, Ricardo M Letelier, Karen L CasciottiAbstract:During austral summer 1997, satellite imagery revealed enhanced chlorophyll associated with the Antarctic Polar Front at 170oW. Phytoplankton growth conditions during the early stages of the spring increase were investigated on the Antarctic Environment and Southern Ocean Process Study Survey I cruise using flow cytometry (FCM) and microscopy to characterize community biomass, composition and biological stratification and dilution experiments to estimate growth and grazing rates. Physical and biological measures showed a general shoaling of mixed layer depth from -200 to 20/xm) cells, greater contributions of diatoms and ciliates, and a twofold higher ratio of protistan grazers to photoautotrophs. Phytoplankton community growth rates from incubations at 10 and 23% of surface incident light showed good agreement between high- performance liquid chromatography estimates of chlorophyll a (Chl a) (0.20 d -l) and FCM cell-based (0.21 d -1) results. Fucoxanthin-based estimates for diatoms were 0.24 d -. Mean estimates of microzooplankton grazing from the three phytoplankton measures were 0.16, 0.12, and 0.11 d - respectively. Heterotrophs typically consumed 40-100% of their body carbon per day and thus presumably grew at rates similar to phytoplankton. The low net rates of Chl a increase in shipboard bottle incubations (0.04 d -1) were consistent with the slow downstream accumulation of phytoplankton biomass (0.03 d -l) as measured with instrumented Lagrangian drifters through the month of November. Both were slightly less than the net rate estimates from SeaSoar surveys (0.05 d -l) because of the effects of pigment photoadaptation (bleaching) during this time of increasing light level and water column stratification.
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Location and dynamics of the Antarctic Polar Front from satellite sea surface temperature data
Journal of Geophysical Research: Oceans, 1999Co-Authors: J. Keith Moore, Mark R Abbott, James G. RichmanAbstract:The location of the Antarctic Polar Front (PF) was mapped over a 7-year period (1987–1993) within images of satellite-derived sea surface temperature. The mean path of the PF is strongly steered by the topographic features of the Southern Ocean. The topography places vorticity constraints on the dynamics of the PF that strongly affect spatial and temporal variability. Over the deep ocean basins the surface expression of the PF is weakened, and the PF meanders over a wide latitudinal range. Near large topographic features, width and temperature change across the Front increase, and large- scale meandering is inhibited. Elevated mesoscale variability is seen within and downstream of these areas and may be the result of baroclinic instabilities initiated where the PF encounters large topographic features. The strong correlations between topography and PF dynamics can be understood in the context of the planetary potential vorticity (PPV or f/H) field. Mean PPV at the PF varies by more than a factor of 2 along its circumPolar path. However, at the mesoscale the PF remains within a relatively narrow range of PPV values around the local mean. Away from large topographic features, the PF returns to a preferred PPV value of ?25 ? 10?9 m?1 s?1 despite large latitudinal shifts. The mean paths of the surface and subsurface expressions of the PF are closely coupled over much of the Southern Ocean.
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variability in the location of the antarctic Polar Front 90 20 w from satellite sea surface temperature data
Journal of Geophysical Research, 1997Co-Authors: Keith J Moore, Mark R Abbott, James G. RichmanAbstract:The path of the Antarctic Polar Front (PF) is mapped using satellite sea surface temperature data from the NOAA/NASA Pathfinder program. The mean path and variability of the PF are strongly influenced by bathymetry. Meandering intensity is weaker where the bathymetry is steeply sloped and increases in areas where the bottom is relatively flat. There is an inverse relationship between meandering intensity and both the width of the Front and the change in temperature across it There is a persistent, large separation between the surface and subsurface expressions of the PF at Ewing Bank on the Falkland Plateau.
James G. Richman - One of the best experts on this subject based on the ideXlab platform.
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Location and dynamics of the Antarctic Polar Front from satellite sea surface temperature data
Journal of Geophysical Research: Oceans, 1999Co-Authors: J. Keith Moore, Mark R Abbott, James G. RichmanAbstract:The location of the Antarctic Polar Front (PF) was mapped over a 7-year period (1987–1993) within images of satellite-derived sea surface temperature. The mean path of the PF is strongly steered by the topographic features of the Southern Ocean. The topography places vorticity constraints on the dynamics of the PF that strongly affect spatial and temporal variability. Over the deep ocean basins the surface expression of the PF is weakened, and the PF meanders over a wide latitudinal range. Near large topographic features, width and temperature change across the Front increase, and large- scale meandering is inhibited. Elevated mesoscale variability is seen within and downstream of these areas and may be the result of baroclinic instabilities initiated where the PF encounters large topographic features. The strong correlations between topography and PF dynamics can be understood in the context of the planetary potential vorticity (PPV or f/H) field. Mean PPV at the PF varies by more than a factor of 2 along its circumPolar path. However, at the mesoscale the PF remains within a relatively narrow range of PPV values around the local mean. Away from large topographic features, the PF returns to a preferred PPV value of ?25 ? 10?9 m?1 s?1 despite large latitudinal shifts. The mean paths of the surface and subsurface expressions of the PF are closely coupled over much of the Southern Ocean.
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variability in the location of the antarctic Polar Front 90 20 w from satellite sea surface temperature data
Journal of Geophysical Research, 1997Co-Authors: Keith J Moore, Mark R Abbott, James G. RichmanAbstract:The path of the Antarctic Polar Front (PF) is mapped using satellite sea surface temperature data from the NOAA/NASA Pathfinder program. The mean path and variability of the PF are strongly influenced by bathymetry. Meandering intensity is weaker where the bathymetry is steeply sloped and increases in areas where the bottom is relatively flat. There is an inverse relationship between meandering intensity and both the width of the Front and the change in temperature across it There is a persistent, large separation between the surface and subsurface expressions of the PF at Ewing Bank on the Falkland Plateau.
