Vertical and small-scale horizontal distribution of chlorophyllaand ATP in subtropical beach sand

Sarsia ◽  
1982 ◽  
Vol 67 (2) ◽  
pp. 79-83 ◽  
Author(s):  
Hein Rune Skjoldal
Keyword(s):  
Horizontal Distribution ◽  
Beach Sand ◽  
Small Scale

Remote Acoustic Detection of Zooplankton Response to Field Processes, Oceanographic Instrumentation, and Predators

1981 ◽  
Vol 38 (9) ◽  
pp. 1096-1105 ◽  
Author(s):  
Marshall H. Orr
Keyword(s):  
Water Column ◽  
Fluid Motion ◽  
Horizontal Distribution ◽  
Small Scale ◽  
Detection Range ◽  
Predator Prey ◽  
Acoustic Backscattering ◽  
Passive Response ◽  
Lee Waves ◽  
Prey Interaction

A narrow-beam multifrequency acoustic backscattering system operating at discrete frequencies in the 10- to 600-kHz band has been used to detect predator–prey interaction, the passive response of Zooplankton to fluid processes such as internal waves, lee waves, hydraulic jumps, and the response of organisms to the presence of an oceanographic instrument in the water column. The acoustic flow visualization data illustrate the extent of the vertical and horizontal displacements and mixing of organisms by fluid processes. The data suggest that fluid processes may strongly influence predator–prey distribution in the continental shelf and sound regimes and that the interpretation of biological field data should include the influence of small-scale fluid motion on the vertical and horizontal distribution of organisms and nutrients. The predator–prey interaction data indicate that small organisms will move 7–20 m in the vertical to avoid larger organisms. Organisms appear to be able to detect the presence of oceanographic instruments to ranges of [Formula: see text]. At this time it is not known whether the organism detection range is related to the optical properties of the water column or other physical parameters.Key words: acoustic, Zooplankton, fluid processes, predator–prey interaction

Impacts of meso and submesoscale dynamics on the horizontal dispersion of sinking particles from the surface to the deep ocean

2020 ◽  
Author(s):  
Lu Wang ◽  
Jonathan Gula ◽  
Jeremy Collin ◽  
Laurent Memery
Keyword(s):  
General Structure ◽  
Finite Size ◽  
Deep Ocean ◽  
Sediment Traps ◽  
Horizontal Distribution ◽  
Particle Dispersion ◽  
Small Scale ◽  
Transport Pathways ◽  
Horizontal Dispersion ◽  
Sinking Particles

<p>Energetic eddy fields generated by meso and submesoscale dynamics induce tridimensional particle transport pathways, which complicate the interpretation of observed Particulate Organic Carbon (POC) fluxes using sediment traps. It is therefore of importance to understand how horizontal dispersion of particles is structured by these dynamics from surface to depth. In this modelling study, we use a Lagrangian method to backtrack sinking particles collected at various depths ranging from 500 m to 4700 m at the PAP (Porcupine Abyssal Plain) site. Particle trajectories are computed using high-resolution simulations of the Regional Ocean Modelling System (ROMS). Our results show that the horizontal distribution of particles with sinking velocities below 100 m d<sup>-1</sup> presents a large small-scale heterogeneity. Mesoscale eddies act to define the general structure of particle patches while submesoscale features shape particle distributions through convergence/divergence processes. Distribution patterns of particles tracked from different depths suggest regime shifts of particle dispersion between subsurface layers. To identify and quantify these regimes, we perform 2d experiments at specific depths from 100 m to 4000 m and relate the Lagrangian statistics to the characteristics of the different dynamical regimes identified using vertical profiles of eddy energy and Finite Size Lyapunov Exponents (FSLE) approach.                                                                                                                                                               </p>

scholarly journals Contamination of beach sand by hookworm species: a small scale observation from Thailand

2016 ◽  
Vol 4 (5) ◽  
pp. 420-420
Author(s):  
Beuy Joob ◽  
◽  
Viroj Wiwanitkit ◽  
Keyword(s):  
Beach Sand ◽  
Small Scale

Vertical and small-scale horizontal distribution of cephalopods in the Charlie-Gibbs Fracture Zone of the Mid-Atlantic Ridge

2020 ◽  
Vol 96 (2) ◽  
pp. 341-356
Author(s):  
Jared Richards ◽  
Michael Vecchione
Keyword(s):  
Fracture Zone ◽  
Diel Vertical Migration ◽  
Large Scale ◽  
Common Species ◽  
Horizontal Distribution ◽  
Small Scale ◽  
Near Surface ◽  
Mid Atlantic Ridge ◽  
Migratory Patterns

In summer 2009, NOAA surveyed the nekton fauna of the fracture zone on the Mid-Atlantic Ridge halfway between Iceland and the Azores as a small-scale follow-up to a previous large-scale Norwegian expedition. Midwater sampling with a Norwegian Krill Trawl resulted in 64 discrete-depth samples from 12 stations at depths from near-surface to 3000 m. Seven additional bottom samples were collected with a large trawl at depths of 2000–3500 m. The expedition collected 416 cephalopods in ca. 19 species in the vicinity of the fracture zone. Over 50 hrs of ROV video from the Norwegian expedition was also viewed to determine diel migratory patterns of the most common species of cephalopod in the region, Gonatus steenstrupi, for comparison with the NOAA trawl data. We found that trawl stations southeast of the Subpolar Front were generally most diverse. Cluster analysis showed that midwater trawls were more similar in species composition than bottom trawls. Unlike in the ROV observations, the small G. steenstrupi from trawl samples did not appear to participate in diel vertical migration, suggesting that trawl-caught juveniles are ecologically distinct from those visible in submersible videos.

Improved Middle Atmosphere Climate and Forecasts in the ECMWF Model through a Nonorographic Gravity Wave Drag Parameterization

2010 ◽  
Vol 23 (22) ◽  
pp. 5905-5926 ◽  
Author(s):  
Andrew Orr ◽  
Peter Bechtold ◽  
John Scinocca ◽  
Manfred Ern ◽  
Marta Janiskova
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Middle Atmosphere ◽  
Forecast Error ◽  
Wave Structure ◽  
Stationary Wave ◽  
Wave Drag ◽  
Horizontal Distribution ◽  
Small Scale ◽  
Temperature Structure

Abstract In model cycle 35r3 (Cy35r3) of the ECMWF Integrated Forecast System (IFS), the momentum deposition from small-scale nonorographic gravity waves is parameterized by the Scinocca scheme, which uses hydrostatic nonrotational wave dynamics to describe the vertical evolution of a broad, constant, and isotropic spectrum of gravity waves emanating from the troposphere. The Cy35r3 middle atmosphere climate shows the following: (i) an improved representation of the zonal-mean circulation and temperature structure; (ii) a realistic parameterized gravity wave drag; (iii) a reasonable stationary planetary wave structure and stationary wave driving in July and an underestimate of the generation of stationary wave activity in the troposphere and stationary wave driving in January; (iv) an improved representation of the tropical variability of the stratospheric circulation, although the westerly phase of the semiannual oscillation is missing; and (v) a realistic horizontal distribution of momentum flux in the stratosphere. By contrast, the middle atmosphere climate is much too close to radiative equilibrium when the Scinocca scheme is replaced by Rayleigh friction, which was the standard method of parameterizing the effects of nonorographic gravity waves in the IFS prior to Cy35r3. Finally, there is a reduction in Cy35r3 short-range high-resolution forecast error in the upper stratosphere.

Small-scale horizontal distribution of coastal copepods

1976 ◽  
Vol 23 (3) ◽  
pp. 241-253 ◽  
Author(s):  
Linda R. Smith ◽  
Charles B. Miller ◽  
Robert L. Holton
Keyword(s):  
Horizontal Distribution ◽  
Small Scale

scholarly journals Potential of airborne lidar measurements for cirrus cloud studies

2014 ◽  
Vol 7 (4) ◽  
pp. 4033-4066
Author(s):  
S. Groß ◽  
M. Wirth ◽  
A. Schäfler ◽  
A. Fix ◽  
S. Kaufmann ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Horizontal Distribution ◽  
Cirrus Clouds ◽  
Airborne Lidar ◽  
Small Scale ◽  
Cirrus Cloud ◽  
Mixing Ratio ◽  
Research Aircraft ◽  
Lidar Observations

Abstract. Aerosol and water vapour measurements were performed with the lidar system WALES of Deutsches Zentrum für Luft- und Raumfahrt (DLR) in October and November 2010 during the first mission with the new German research aircraft G55-HALO. Curtains composed of lidar profiles beneath the aircraft show the vertical and horizontal distribution and variability of water vapour mixing ratio and backscatter ratio above Germany. Two missions on 3 and 4 November 2010 were selected to derive the water vapour mixing ratio inside cirrus clouds from the lidar instrument. A good agreement was found with in-situ observations performed on a second research aircraft flying below HALO. ECMWF analysis temperature data are used to derive relative humidity fields (RHi) inside and outside of cirrus clouds from the lidar water vapour observations. The RHi variability is dominated by small scale fluctuations in the water vapour fields while the temperature variation has a minor impact. The most frequent in-cloud RHi value from lidar observations is 98%. The RHi variance is smaller inside the cirrus than outside of the cloud. 2-dimensional histograms of relative humidity and backscatter ratio show significant differences for in-cloud and out-of cloud situations for two different cirrus cloud regimes. Combined with accurate temperature measurements, the lidar observations have a great potential for detailed statistical cirrus cloud and related humidity studies.

scholarly journals The chemical transport model Oslo CTM3

2012 ◽  
Vol 5 (6) ◽  
pp. 1441-1469 ◽  
Author(s):  
O. A. Søvde ◽  
M. J. Prather ◽  
I. S. A. Isaksen ◽  
T. K. Berntsen ◽  
F. Stordal ◽  
...  
Keyword(s):  
Large Scale ◽  
Transport Model ◽  
Chemical Transport ◽  
Horizontal Distribution ◽  
Small Scale ◽  
Chemical Transport Model ◽  
Polar Cap ◽  
Time Step ◽  
Transport Time ◽  
Fractional Cloud

Abstract. We present here the global chemical transport model Oslo CTM3, an update of the Oslo CTM2. The update comprises a faster transport scheme, an improved wet scavenging scheme for large scale rain, updated photolysis rates and a new lightning parameterization. Oslo CTM3 is better parallelized and allows for stable, large time steps for advection, enabling more complex or high spatial resolution simulations. A new treatment of the horizontal distribution of lightning is presented and found to compare well with measurements. The vertical distribution of lightning is updated and found to be a large contributor to CTM2–CTM3 differences, producing more NOx in the tropical middle troposphere, and less at the surface and at high altitudes. Compared with Oslo CTM2, Oslo CTM3 is faster, more capable and has better conceptual models for scavenging, vertical transport and fractional cloud cover. CTM3 captures stratospheric O3 better than CTM2, but shows minor improvements in terms of matching atmospheric observations in the troposphere. Use of the same meteorology to drive the two models shows that some features related to transport are better resolved by the CTM3, such as polar cap transport, while features like transport close to the vortex edge are resolved better in the Oslo CTM2 due to its required shorter transport time step. The longer transport time steps in CTM3 result in larger errors, e.g., near the jets, and when necessary the errors can be reduced by using a shorter time step. Using a time step of 30 min, the new transport scheme captures both large-scale and small-scale variability in atmospheric circulation and transport, with no loss of computational efficiency. We present a version of the new transport scheme which has been specifically tailored for polar studies, resulting in more accurate polar cap transport than the standard CTM3 transport, confirmed by comparison to satellite observations. Inclusion of tropospheric sulfur chemistry and nitrate aerosols in CTM3 is shown to be important to reproduce tropospheric O3, OH and the CH4 lifetime well.

scholarly journals Potential of airborne lidar measurements for cirrus cloud studies

2014 ◽  
Vol 7 (8) ◽  
pp. 2745-2755 ◽  
Author(s):  
S. Groß ◽  
M. Wirth ◽  
A. Schäfler ◽  
A. Fix ◽  
S. Kaufmann ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Horizontal Distribution ◽  
Cirrus Clouds ◽  
Airborne Lidar ◽  
Small Scale ◽  
Cirrus Cloud ◽  
Mixing Ratio ◽  
Research Aircraft ◽  
Lidar Observations

Abstract. Aerosol and water vapour measurements were performed with the lidar system WALES of Deutsches Zentrum für Luft- und Raumfahrt (DLR) in October and November 2010 during the first mission with the new German research aircraft G55-HALO. Curtains composed of lidar profiles beneath the aircraft show the vertical and horizontal distribution and variability of water vapour mixing ratio and backscatter ratio above Germany. Two missions on 3 and 4 November 2010 were selected to derive the water vapour mixing ratio inside cirrus clouds from the lidar instrument. A good agreement was found with in situ observations performed on a second research aircraft flying below HALO. ECMWF analysis temperature data are used to derive relative humidity fields with respect to ice (RHi) inside and outside of cirrus clouds from the lidar water vapour observations. The RHi variability is dominated by small-scale fluctuations in the water vapour fields while the temperature variation has a minor impact. The most frequent in-cloud RHi value from lidar observations is 98%. The RHi variance is smaller inside the cirrus than outside of the cloud. 2-D histograms of relative humidity and backscatter ratio show significant differences for in-cloud and out-of-cloud situations for two different cirrus cloud regimes. Combined with accurate temperature measurements, the lidar observations have a great potential for detailed statistical cirrus cloud and related humidity studies.

Hyperiid amphipod vertical distribution and community structure in the upper 100 m of the northwestern Caribbean Sea

2021 ◽  
Author(s):  
Anahí Domínguez-Nava ◽  
Rebeca Gasca ◽  
Laura Carrillo ◽  
Lourdes Vásquez-Yeomans ◽  
Eduardo Suárez-Morales
Keyword(s):  
Community Structure ◽  
Vertical Distribution ◽  
Environmental Variability ◽  
Principal Component ◽  
Caribbean Sea ◽  
Abundant Species ◽  
Horizontal Distribution ◽  
Small Scale ◽  
Principal Coordinates ◽  
Abundance And Diversity

The community structure and variability of the hyperiid amphipods of the Northwestern Tropical Atlantic (NWTA) remain largely unknown. We described and analyzed the hyperiid nictemeral, vertical, and horizontal distribution and the influence of environmental variables in the upper 100 m of the northwestern Caribbean Sea. We examined 196 zooplankton samples obtained during both day and nighttime at four depth strata from 49 sampling stations in January 2007. Up to 82 hyperiid species including 14 new regional records were identified and quantified. Both day/night and some interstrata differences were significant, particularly in reference to the uppermost and deepest strata. The local hyperiid community structure appeared to be profiled by the frequency and abundance variations of the two most abundant species, Lestrigonus bengalensis and Brachyscelus crusculum, both being most abundant in the uppermost (0–25 m) stratum. The horizontal distribution of the highest hyperiid abundance and diversity appears to be related to the influence of mesoscale processes like upwelling and cyclonic eddies. The Gulf of Honduras area had relatively low hyperiid abundances. The principal component analysis revealed density and temperature as the main factors explaining the local environmental variability. The canonical analysis of principal coordinates (CAP) showed that salinity and temperature strongly influenced the variability of the local hyperiid community. Overall, the two middle vertical strata (25–75 m) were relatively uniform; the main differences were found only between the uppermost and deepest strata. This study is the first to provide information regarding small-scale vertical distribution of hyperiid amphipods in the NWTA.

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