Southampton Oceanography Centre Research Articles

Temporal and spatial changes in mixed layer properties and atmospheric net heat flux in the Nordic Seas

The Nordic Seas are an important area of the World Ocean where warm Atlantic waters penetrate far north forming the mild climate of Northern Europe. These waters represent the northern rim of the global thermohaline circulation. Estimates of the relationships between the net heat flux and mixed layer properties in the Nordic Seas are examined. Oceanographic data are derived from the Oceanographic Data Base (ODB) compiled in the Arctic and Antarctic Research Institute. Ocean weather ship 'Mike' (OWS) data are used to calculate radiative and turbulent components of the net heat flux. The net shortwave flux was calculated using a satellite albedo dataset and the EPA model. The net longwave flux was estimated by Southampton Oceanography Centre (SOC) method. Turbulent fluxes at the air-sea interface were calculated using the COARE 3.0 algorithm. The net heat flux was calculated by using oceanographic and meteorological data of the OWS 'Mike'. The mixed layer depth was estimated for the period since 2002 until 2009 by the 'Mike' data as well. A good correlation between these two parameters has been found. Sensible and latent heat fluxes controlled by surface air temperature/sea surface temperature gradient are the main contributors into net heat flux. Significant correlation was found between heat fluxes variations at the OWS 'Mike' location and sea ice export from the Arctic Ocean.

Annual, Seasonal, and Interannual Variability of Air–Sea Heat Fluxes in the Indian Ocean

Abstract This study investigated the accuracy and physical representation of air–sea surface heat flux estimates for the Indian Ocean on annual, seasonal, and interannual time scales. Six heat flux products were analyzed, including the newly developed latent and sensible heat fluxes from the Objectively Analyzed Air–Sea Heat Fluxes (OAFlux) project and net shortwave and longwave radiation results from the International Satellite Cloud Climatology Project (ISCCP), the heat flux analysis from the Southampton Oceanography Centre (SOC), the National Centers for Environmental Prediction reanalysis 1 (NCEP1) and reanalysis-2 (NCEP2) datasets, and the European Centre for Medium-Range Weather Forecasts operational (ECMWF-OP) and 40-yr Re-Analysis (ERA-40) products. This paper presents the analysis of the six products in depicting the mean, the seasonal cycle, and the interannual variability of the net heat flux into the ocean. Two time series of in situ flux measurements, one taken from a 1-yr Arabian Sea Experiment field program and the other from a 1-month Joint Air–Sea Monsoon Interaction Experiment (JASMINE) field program in the Bay of Bengal were used to evaluate the statistical properties of the flux products over the measurement periods. The consistency between the six products on seasonal and interannual time scales was investigated using a standard deviation analysis and a physically based correlation analysis. The study has three findings. First of all, large differences exist in the mean value of the six heat flux products. Part of the differences may be attributable to the bias in the numerical weather prediction (NWP) models that underestimates the net heat flux into the Indian Ocean. Along the JASMINE ship tracks, the four NWP modeled mean fluxes all have a sign opposite to the observations, with NCEP1 being underestimated by 53 W m−2 (the least biased) and ECMWF-OP by 108 W m−2 (the most biased). At the Arabian Sea buoy site, the NWP mean fluxes also have an underestimation bias, with the smallest bias of 26 W m−2 (ERA-40) and the largest bias of 69 W m−2 (NCEP1). On the other hand, the OAFlux+ISCCP has the best comparison at both measurement sites. Second, the bias effect changes with the time scale. Despite the fact that the mean is biased significantly, there is no major bias in the seasonal cycle of all the products except for ECMWF-OP. The latter does not have a fixed mean due to the frequent updates of the model platform. Finally, among the four products (OAFlux+ISCCP, ERA-40, NCEP1, and NCEP2) that can be used for studying interannual variability, OAFlux+ISCCP and ERA-40 Qnet have good consistency as judged from both statistical and physical measures. NCEP1 shows broad agreement with the two products, with varying details. By comparison, NCEP2 is the least representative of the Qnet variabilities over the basin scale.

Comparing 20 years of precipitation estimates from different sources over the world ocean

The paper compares ten different global precipitation data sets over the oceans and discusses their respective strengths and weaknesses in ocean regions where they are potentially important to the salinity and buoyancy budgets of surface waters. Data sets (acronyms of which are given in Section 2) are categorised according to their source of data, which are (1) in situ for Center for Climatic Research (Legates and Willmott, 1990; Archive of Precipitation Version 3.01, http://climate.geog.udel.edu/~climate), Southampton Oceanography Centre (SOC) (Josey et al., J Clim 12:2856–2880, 1999) and University of Wisconsin-Milwaukee (UWM) (Da Silva et al. 1994); (2) satellite for Microwave Sounding Unit (MSU) (Spencer, J Clim 6:1301–1326, 1993), TOPEX (Quartly et al., J Geophys Res 104:31489–31516, 1999), and Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite (HOAPS) (Bauer and Schluessel, J Geophys Res 98:20737–20759, 1993); (3) atmospheric forecast model re-analyses for European Centre for Medium-range Weather Forecast (ECMWF) (Gibson et al. 1997) and National Center for Environmental Prediction (NCEP) (Kalnay et al., Bull Am Meteorol Soc 77:437–471, 1996); and (4) composite for Global Precipitation Climatology Project (GPCP) (satellites and rain gauges, Huffman et al., Bull Am Meteorol Soc 78(1):5–20, 1997) and Climate Prediction Center Merged Analysis of Precipitation (CMAP) (satellites, rain gauges and atmospheric forecast model, Xie and Arkin, Bull Am Meteorol Soc 78(11):2539–2558, 1997). Although there is no absolute field of reference, composite data sets are often considered as the best estimates. First, a qualitative comparison is carried out, which provides for each data set, a description of the geographical distribution of the climatological mean precipitation field. A more careful comparison between data sets is undertaken over periods they have in common. First, six among the ten data sets (SOC, UWM, ECMWF, NCEP, MSU and CMAP) are compared over their common period of 14 years, from 1980 to 1993. Then CMAP is compared to GPCP over the 1988–1995 period and to HOAPS over the 1992–1998 period. Usual diagnostics, like comparison of the precipitation patterns exhibited in the annual climatological means of zonal averages and global budget, are used to investigate differences between the various precipitation fields. In addition, precipitation rates are spatially integrated over 16 regional boxes, which are representative of the major ocean gyres or large-scale ocean circulation patterns. Seasonal and inter-annual variations are studied over these boxes in terms of time series anomalies or correlation coefficients. The analysis attempts to characterise differences and biases according to the original source of data (i.e. in situ or satellite, etc.). Qualitative agreement can be observed in all climatologies, which reproduce the major characteristics of the precipitation patterns over the oceans. However, great disagreements occur in terms of quantitative values and regional patterns, especially in regions of high precipitation. However, a better agreement is generally found in the northern hemisphere. The most significant differences, observed between data sets in the mean seasonal cycles and interannual variations, are discussed. A major result of the paper, which was not expected a priori, is that differences between data sets are much more dependent upon the ocean region that is considered than upon the origin of the data sets (in situ vs satellite vs model, etc.). Our analysis did not provide enough objective elements, which would allow us to clearly recommend a given data set as reference or best estimate. However, composite data sets (GPCP, and especially CMAP), because they never appeared to be really “off” when compared to other data sets, may represent the best recent data set available. CMAP would certainly be our first choice to drive an ocean GCM.

Remote visualisation of Labrador convection in large oceanic datasets

AbstractThe oceans relinquish O(1PW) of heat into the atmosphere at high latitudes, the lion's share of which originates in localised ‘hotspots’ of violent convective mixing, but despite their small horizontal scale—O(10–100km)—these features may penetrate deeply into the thermocline and are vital in maintaining the Atlantic Meridional Overturning Circulation (MOC). Accurate modelling of the MOC, therefore, requires a large‐scale numerical model with very fine resolution.The global high‐resolution ocean model, Ocean Circulation Climate Advanced Model (OCCAM) has been developed and run at the Southampton Oceanography Centre (SOC) for many years. It was configured to resolve the energetic scales of oceanic motions, and its output is stored at the Manchester Supercomputer Centre. Although this community resource represents a treasure trove of potential new insights into the nature of the world ocean, it remains relatively unexploited for a number of reasons, not the least of which is its sheer size.A system being developed at SOC under the auspices of the Grid for Ocean Diagnostics, Interactive Visualisation and Analysis (GODIVA) project makes the remote visualisation of very large volumes of data on modest hardware (e.g. a laptop with no special graphics capability) a present reality. The GODIVA system is enabling the unresolved question of oceanic convection and its relationship to large‐scale flows to be investigated; a question that lies at the heart of many current climate change issues.In this article, one aspect of the GODIVA is presented, and used to locate and visualise regions of convective mixing in the OCCAM Labrador Sea. Copyright © 2006 Royal Meteorological Society

Slope failure, mass flow and bottom current processes in the Rockall Trough, offshore Ireland, revealed by deep-tow sidescan sonar

The margins of the Rockall Trough, currently the focus of oil and gas exploration interest, incorporate an environmentallyimportant and lightly studied shelf region. To address the paucity of information within this region an extensive high resolution sidescan sonar survey was carried out in the Irish sector of the Rockall Trough in June/July 1998. This valuable natural laboratory contains information on slope stability, sediment transport, nutrient upwelling, bottom current, and biological activity at a shelf/slope/basin-floor transition. Detailed information on the nature of many of these processes can be provided from shallow geophysical techniques. The TRIM (TOBI Rockall Irish Margins) project (Shannon et al., 2001), funded by the Irish Petroleum Infrastructure Programme (Rockall Studies Group), acquired 3100 line-km of TOBI sidescan sonar and 3700 km of 3.5 kHz profiler data along the margins of the Rockall Trough (Figure 1). This project followed on from the earlier reconnaissance AIRS (Atlantic Irish Regional Survey) survey conducted over the entire southern Rockall Trough region, using the lower resolution surface towed sonar side-scan system known as GLORIA (Unnithan et al., 2001). The TOBI sidescan system, developed at the Southampton Oceanography Centre (Flewellen et al., 1993), is deep-towed at 300-400 m above the seafloor. It transmits at a frequency of 32 kHz and samples the acoustic response of the seabed and shallow sedimentary structure to a centimetre to metre depth scale. This acoustic response therefore reflects not only the backscattering properties of the seabed but also the shallow detailed structure of sediments formed by recent sedimentological processes.

Improving Latent and Sensible Heat Flux Estimates for the Atlantic Ocean (1988–99) by a Synthesis Approach*

A new daily latent and sensible flux product developed at the Woods Hole Oceanographic Institution (WHOI) with 1 83 18 resolution for the Atlantic Ocean (658S‐658N) for the period from 1988 to 1999 was presented. The flux product was developed by using a variational objective analysis approach to obtain best estimates of the flux-related basic surface meteorological variables (e.g., wind speed, air humidity, air temperature, and sea surface temperature) through synthesizing satellite data and outputs of numerical weather prediction (NWP) models at the National Centers for Environmental Prediction (NCEP) and the European Centre for MediumRange Weather Forecasts (ECMWF). The state-of-the-art bulk flux algorithm 2.6a, developed from the field experiments of the Coupled Ocean‐Atmosphere Response Experiment (COARE), was applied to compute the flux fields. The study focused on analyzing the mean field properties of the WHOI daily latent and sensible heat fluxes and their comparisons with the ship-based climatology from the Southampton Oceanography Centre (SOC) and NWP outputs. It is found that the WHOI yearly mean fluxes are consistent with the SOC climatology in both structure and amplitude, but the WHOI yearly mean basic variables are not always consistent with SOC; the better agreement in the fluxes is due to the effects of error compensation during variable combinations. Both ECMWF and NCEP‐Department of Energy (DOE) Atmospheric Model Intercomparison Project (AMIP) Reanalysis-2 (NCEP2) model data have larger turbulent heat loss (; 20 Wm 22) than the WHOI product. Nevertheless, the WHOI fluxes agree well with the NCEP-2 Reanalysis fluxes in structure and the trend of year-toyear variations, but not with the ECMWF operational outputs; the latter have a few abrupt changes coinciding with the modifications in the model forecast‐analysis system. The degree of impact of the model changes on the basic variables is not as dramatic, a factor that justifies the inclusion of the basic variables, not the fluxes, from the ECMWF operational model in the synthesis. The flux algorithms of the two NWP models give a larger latent and sensible heat loss. Recalculating the NWP fluxes using the COARE algorithm considerably reduces the strength but does not replicate the WHOI results. The present analysis could not quantify the degree of improvement in the mean aspect of the WHOI daily flux fields as accurate basinwide verification data are lacking. This study is the first to demonstrate that the synthesis approach is a useful tool for combining the NWP and satellite data sources and improving the mean representativeness of daily basic variable fields and, hence, the daily flux fields. It is anticipated that such an approach may become increasingly relied upon in the preparation of future high-quality flux products.

Observations of seasonal exchange through the Straits of Hormuz and the inferred heat and freshwater budgets of the Persian Gulf

The exchange between the Persian (Arabian) Gulf and the Indian Ocean is investigated using hydrographic and moored acoustic Doppler current profiler data from the Straits of Hormuz during the period December 1996 to March 1998. The moored time series records show a relatively steady deep outflow through the strait from 40 m to the bottom with a mean speed of approximately 20 cm/s. A variable flow is found in the upper layer with frequent reversals on timescales of several days to weeks. The annual mean flow in the near‐surface layer is found to be northeastward (out of the Persian Gulf) in the southern part of the strait, suggesting a mean horizontal exchange with the Indian Ocean that is superimposed on the vertical overturning exchange driven by evaporation over the gulf. The salinity of the deep outflow varies from 39.3 to 40.8 psu with highest outflow salinities occurring in the winter months (December–March). The annual mean deep outflow through the strait is estimated to be 0.15 ± 0.03 Sv. Calculation of the associated heat and freshwater fluxes through the strait yields estimates for the annual heat loss over the surface of the gulf of −7 ± 4 W/m2 and an annual water loss (E‐P‐R) of 1.68 ± 0.39 m/yr. These values are shown to be in relatively good agreement with climatological surface fluxes derived from the Southampton Oceanography Centre global flux climatology after known regional biases in the radiative budget are taken into account.

Inverse Analysis Adjustment of the SOC Air–Sea Flux Climatology Using Ocean Heat Transport Constraints

Results are presented from a linear inverse analysis of the Southampton Oceanography Centre (SOC) air–sea flux climatology using 10 hydrographic ocean heat transport constraints distributed throughout the Atlantic and North Pacific Oceans. A solution is found that results in an adjusted set of fluxes that is consistent with all of the available constraints within their estimated error bounds. The global mean net ocean heat loss to the atmosphere with these adjustments is –5 W m–2, compared with a gain of 30 W m–2 for the original climatology. The primary changes to the net heat flux arise from an increase of 15% to the latent heat and reduction of 9% to the shortwave flux. The analysis has been extended to include the additional constraint that the global mean net heat flux lies in the range 0 ± 2 W m–2. In the latter case, the solution is modified such that the adjustment of the latent heat increases to 19%, the reduction of the shortwave decreases to 6%, and the global mean net heat flux is –2 W m–2. The adjusted SOC fluxes with both solutions agree to within 7 W m–2 with independent large-scale area average heat flux estimates obtained from a hydrographic section at 32°S that was withheld from the analysis. Good agreement is also found with recent estimates of the global ocean heat transport obtained using residual techniques and from atmospheric model reanalyses. However, additional comparisons of the adjusted fluxes with measurements made by various Woods Hole Oceanographic Institute research buoys indicate that further improvements to the inverse analysis are still required. Modifications to the analysis scheme are suggested that may lead to further improvements to the adjusted fluxes, in particular, the explicit use of the buoy measurements as constraints.

Changes in the heat and freshwater forcing of the eastern Mediterranean and their influence on deep water formation

Anomalies in the air‐sea heat and freshwater forcing of the eastern Mediterranean are related to observations of deep water formation in the Aegean Sea between 1987 and 1995. Fields of the buoyancy exchange (expressed as a density flux) are determined from the Southampton Oceanography Centre (SOC) flux climatology and National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. A coherent picture emerges from the two data sets, in both cases the strongest losses occur in winters 1991–1992 and 1992–1993, when Aegean Sea net heat loss and net evaporation anomalies of 60 W m−2 and 0.05 m month−1, respectively, are found. These correspond to thermal and haline density fluxes of 3.3 × 10−6 and 0.6 × 10−6 kg m−2 s−1. Thus the thermal term makes the major contribution to the increase in density of the surface waters over these winters and the haline term plays only a minor role. Similar results are obtained when annual mean fields are considered as the winter forcing dominates. The NCEP/NCAR reanalysis is used to place the winters of the early 1990s in the context of variability over the longer period 1949–2002. Anomalous winter losses of similar magnitude occurred in the mid‐1970s and the possibility of a related previous episode of deep water formation in the Aegean is discussed. The relationship between Aegean Sea heat loss and large‐scale atmospheric pressure patterns is also investigated. Heat loss anomalies are found to be uncorrelated with the North Atlantic Oscillation. However, a strong correlation (r2 = 0.52) is found with a pattern whose main feature is anomalously high pressure over western Europe.

Time-lapse Photography in the Deep Sea

Time-lapse photography (TLP) has been used in scientific applications for over 100 years, and has been used in deep-sea operations for the last three decades. Here I review the use of TLP in deep-sea science by reference to case studies drawn from a 20-year history of “Bathysnap” (Southampton Oceanography Centre’s TLP system) deployments in the NE Atlantic. Examples are given of: a) echiuran feeding, b) xenophyophore growth, c) benthopelagic scavengers, and d) long-term studies of phytodetritus. Although the technology for TLP will change over time, the concept remains of great value in studying the remote deep-sea environment.

Intercomparison of Heat Fluxes in the South Atlantic. Part I: The Seasonal Cycle

Abstract Intercomparison of the seasonal cycle for the fluxes of sensible and latent heat for four observation-based products [DaSilva, NCEP, Esbensen–Kushnir (EK), and the Southampton Oceanography Centre (SOC)] and the results for the NCAR Community Climate System Model (CCSM) are examined in order to gain an improved understanding of the South Atlantic characteristic spatial patterns. Their seasonal structure associated with ocean dynamics, evolution, and the net heat flux patterns are also discussed. The key regions of the Brazil–Malvinas confluence, Agulhas retroflection, and Benguela upwelling region off Africa were chosen for a closer examination of the fluxes. All climatologies show very different behavior. The SOC product presents sudden changes in the seasonal cycle evolution, departing from the annual or semiannual observed pattern of EK and NCEP. Compared to the other climatologies, EK shows equivalent temporal behavior but different magnitudes because this climatology covers a period where muc...

Wind Stress Forcing of the Ocean in the SOC Climatology: Comparisons with the NCEP–NCAR, ECMWF, UWM/COADS, and Hellerman and Rosenstein Datasets

Results from an analysis of the Southampton Oceanography Centre (SOC) global wind stress climatology, which is based on in situ reports for the period 1980-93, are presented. The accuracy of the SOC stresses has been assessed at several locations by comparison of individual monthly means with measurements from Woods Hole Oceanographic Institution research buoy deployments. For the subduction buoy array, situated in the subtropical North Atlantic, the random error in the SOC individual monthly mean wind stress ranges from 0.004 to 0.008 N m-2, which corresponds to between 5% and 10% of the mean stress depending on which buoy is considered. The large-scale characteristics of the SOC fields are compared with those of the NCEP-NCAR and ECMWF atmospheric model reanalyses, and the in situ observation based on the University of Wisconsin-Milwaukee/Comprehensive Ocean–Atmosphere Dataset (UWM/COADS) and Hellerman and Rosenstein (HR) climatologies. The NCEP-NCAR fields show noticeably weaker wind stress forcing in the Tropics than SOC, while ECMWF and UWM/COADS are in good agreement. From the Tropics to the midlatitudes, the HR stresses tend to be stronger than SOC and the other recent climatologies. At higher latitudes, differences in the spatial structure of the Northern Hemisphere subpolar gyres in SOC and HR are found that are consistent with variations in the state of the North Atlantic and North Pacific Oscillations within the periods on which the climatologies are based. A detailed comparison of the wind-driven response of the ocean is presented for SOC and HR. The North Atlantic subpolar gyre is more intense in SOC than HR and this leads to a doubling in the strength of the Ekman suction. January mean upwelling velocities in this region deduced from the two datasets are 18.9 and 8.6 m month-1, respectively. In the North Pacific a single large-scale subpolar gyre is evident in SOC compared with two smaller gyres in HR. Seasonal to interannual variability in the wind-driven ocean response is quantified using an extended version of the SOC dataset covering the period 1980–97. Significant variability in the Ekman transport across several latitudes that correspond to WOCE hydrographic sections is observed and related to the major atmospheric pressure oscillations

HOAPS - A new satellite-derived freshwater flux climatology

HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data) is a global climatology of sea surface parameters and surface energy and freshwater fluxes derived from satellite radiances for the time period July 1987 to December 1998. Data from polar orbiting radiometers, the Special Sensor Microwave/Imager (SSM/I) and the Advanced Very High Resolution Radiometer (AVHRR), have been used to get global fields of surface meteorological and oceanographic parameters but also latent heat flux, evaporation, precipitation and net freshwater flux over ice free ocean areas for various averaging periods and grid sizes. All retrieval methods have been validated with in situ data on a global scale to the extent possible. In this paper some of the major outcomes are exemplarily shown together with the results of comparison studies with the in situ climatology provided by the Southampton Oceanography Centre (SOC).

Effect of food quality on carbon and nitrogen growth efficiency in the copepod Acartia tonsa

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 235:147-156 (2002) - doi:10.3354/meps235147 Effect of food quality on carbon and nitrogen growth efficiency in the copepod Acartia tonsa Ruth H. Jones1, Kevin J. Flynn1,*, Thomas R. Anderson2 1Ecology Research Unit, School of Biological Sciences, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, United Kingdom 2George Deacon Division, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom *Corresponding author. E-mail: k.j.flynn@swansea.ac.uk ABSTRACT: Populations of the copepod Acartia tonsa were fed a mixture of algal prey (diatom Thalassiosira weissflogii, prymnesiophyte Emiliania huxleyi, dinoflagellate Aureodinium [Gymnodium] pigmentosum) supplied at saturating concentrations, grown under either nitrogen-sufficient or nitrogen-deplete conditions, in order to study the impact of food quality on production and development throughout the life cycle of the copepod. Changes in predator population structure and biomass were recorded, along with consumption of each of the algal groups, permitting C and N growth efficiencies to be estimated. There was a clear difference in the Acartia tonsa population structure when fed N sufficient or N-deplete prey, with those fed N-deplete prey slower to develop and reproduce and laying fewer eggs. Algal nutrient status affected selectivity between the diatom and dinoflagellate, the latter being favoured under nutrient-deplete conditions, perhaps in part because their C:N ratio was less susceptible to altered nutrient status. There was no clear difference in the N growth efficiency (N GE, typically 5%) between N-sufficient and N-deplete prey, but certainly efficiency did not increase with N-deplete prey. C growth efficiency (C-GE) declined from 5 to 2% with N-deplete prey. However, while the ratio of N-GE:C-GE was clearly different between N-sufficient (1) and N-deplete (2.5) treatments, actual growth efficiencies increased with time during the progression to later life history stages, culminating in highest efficiencies during active egg production. Caution should be exercised in assigning GE and predation rates in models incorporating zooplankton feeding on prey of variable nutrient status; these parameters are not constants and GE estimates from egg production experiments are likely to significantly overestimate efficiencies over the whole copepod life cycle. KEY WORDS: Copepods · Food quality · Nutrient status · C:N · Growth efficiency · Population · Life cycle Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 235. Online publication date: June 19, 2002 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2002 Inter-Research.

Deep‐sea, high‐resolution, hydrography and current measurements using an autonomous underwater vehicle: The overflow from the Strait of Sicily

AUTOSUB‐2, an autonomous underwater vehicle (AUV) developed by the Southampton Oceanography Centre, was used for high resolution hydrographic surveys in the Sicily Strait. A combination of “seasoar” type profiling and terrain following missions were undertaken and velocity and hydrographic measurements taken from AUTOSUB‐2 were compared with concurrent shipboard hydrographic and velocity profiles. Even though shipboard stations were separated by just 5 to 8 km along the mission path, data from the AUV showed small scale variability that was missed by the shipboard sampling. In this paper we present the example of an intense jet, with maximum speed greater than 0.50 m s−1, less than 4 km wide.

Movement of wild European lobsters Homarus gammarus in natural habitat

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 222:177-186 (2001) - doi:10.3354/meps222177 Movement of wild European lobsters Homarus gammarus in natural habitat I. P. Smith*, A. C. Jensen, K. J. Collins, E. L. Mattey School of Ocean and Earth Science, University of Southampton, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom *E-mail: philip.smith@soc.soton.ac.uk ABSTRACT: Most previous mark-recapture studies of the movement of European lobsters have used externally attached tags which were lost at ecdysis, restricting the range of possible recapture intervals. Published studies of this species with tags designed to be retained through ecdysis have focussed on artificially reared lobsters, or wild lobsters released in artificial habitat. Here, we report a mark-recapture study of the mobility of wild European lobsters conducted in 3 areas on the south coast of England, using persistent tags. Tagged lobsters were smaller than the fishery minimum landing size (50 to 84 mm carapace length) and were therefore likely to be predominantly sexually immature. The majority of these lobsters do not appear to undertake extensive alongshore or on-/offshore migrations. Recapture distances ranged from 0 to 45 km, but 95% of recaptured lobsters moved <3.8 km from their original release positions over periods of up to 862 d. Distance moved did not differ between males and females, but there was a weak positive relationship between recapture distance and body size. The directional distribution of movements >0.5 km differed between the 3 study areas and appeared to be related to the spatial configuration of local lobster habitat, but with a marked tendency for offshore movement in 2 of the areas. Movements >5 km from all 3 release areas, which comprised 5% of recaptures after >6 mo, were generally undertaken by larger lobsters and were almost exclusively to the west or southwest, against the general direction of tide- and wind-generated residual water movement in the English Channel. KEY WORDS: Lobster · Mark-recapture · Movements · Migrations · Tagging Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 222. Online publication date: November 05, 2001 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2001 Inter-Research.

The Arctic Ocean Circulation as simulated in a very high-resolution global ocean model (OCCAM)

AbstractTo investigate the Arctic Ocean Circulation, results from a high-resolution fully global ocean model have been analyzed. The results come from two runs of the Ocean Circulation and Climate Advanced Modelling project (OCCAM) model, developed and run by the Southampton Oceanography Centre, at 1/4° × 1/4° and 1/8° × 1/8° resolution. The model is based on the Bryan-Semtner-Cox model and has 36 vertical levels. Enhancements include a free surface, an improved advection scheme and an improved treatment of the surface fresh-water flux. The model is forced with a monthly European Centre for Medium-range Weather Forecasts wind-stress climatology. It reproduces many of the fine-scale features found in the Arctic Ocean. The analysis concentrates on several of the key features, including the highly energetic eddy system in the western part of the Beaufort Sea, East Greenland West and Spitsbergen Currents and the detailed structure of the marginal currents along the Siberian and Canadian coasts. Much of the paper is focused on the water transport through the Bering and Fram Straits and through the Canadian Archipelago. Comparisons of the model net fluxes through the straits against observations are presented. The analyses of the results demonstrate the ability of the fine-resolution model to simulate features such as small-scale eddies and jets, which have some agreement with the limited observations available.

Constraining fault growth rates and fault evolution in New Zealand

Understanding how faults propagate, grow, and interact in fault systems is important because they are primarily responsible for distributing strain in the upper crust. They localize deformation and stress release, often producing surface displacements that control sedimentation and fluid flow, either by acting as conduits or barriers. Identifying fault spatial distribution, quantifying activity, evaluating linkage mechanisms, and estimating fault growth rates are key components in seismic risk evaluation.Scientists from the National Institute of Water and Atmospheric Research (NIWA), New Zealand, and the Southampton Oceanography Centre, United Kingdom, are working on a collaborative project that aims to improve understanding of faulting processes in the Earth's crust.The program comprises two research cruises to survey the Whakatane Graben, New Zealand, which is a zone of intense seismicity active extensional faulting, and rapid subsidence within the back‐arc region of the Pacific‐Australia plate boundary zone (Figure 1). Few places in the world offer the same opportunity to study the mechanisms by which major crustal faults have grown from small‐ to large‐scale structures capable of generating moderate to large‐magnitude earthquakes.

MAJOR ASPECTS OF FORAMINIFERAL VARIABILITY (STANDING CROP AND BIOMASS) ON A MONTHLY SCALE IN AN INTERTIDAL ZONE

Research Article| July 01, 2000 MAJOR ASPECTS OF FORAMINIFERAL VARIABILITY (STANDING CROP AND BIOMASS) ON A MONTHLY SCALE IN AN INTERTIDAL ZONE John W. Murray; John W. Murray 1School of Ocean and Earth Science, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, England. Search for other works by this author on: GSW Google Scholar Elisabeth Alve Elisabeth Alve 2Department of Geology, University of Oslo, PO Box 1047 Blindern, N-0316 Oslo, Norway. Search for other works by this author on: GSW Google Scholar Author and Article Information John W. Murray 1School of Ocean and Earth Science, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, England. Elisabeth Alve 2Department of Geology, University of Oslo, PO Box 1047 Blindern, N-0316 Oslo, Norway. Publisher: Cushman Foundation for Foraminiferal Research Received: 12 Aug 1999 Accepted: 19 Nov 1999 First Online: 03 Mar 2017 Online ISSN: 1943-264X Print ISSN: 0096-1191 © 2000 Journal of Foraminiferal Research Journal of Foraminiferal Research (2000) 30 (3): 177–191. https://doi.org/10.2113/0300177 Article history Received: 12 Aug 1999 Accepted: 19 Nov 1999 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation John W. Murray, Elisabeth Alve; MAJOR ASPECTS OF FORAMINIFERAL VARIABILITY (STANDING CROP AND BIOMASS) ON A MONTHLY SCALE IN AN INTERTIDAL ZONE. Journal of Foraminiferal Research 2000;; 30 (3): 177–191. doi: https://doi.org/10.2113/0300177 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyJournal of Foraminiferal Research Search Advanced Search Abstract Temporal and spatial variability of intertidal benthic foraminiferal assemblages in the surface (0–1 cm) sediments have been determined by a time series survey (27 months) of the Hamble estuary, southern England. One pair of replicates was collected each month from two stations at different elevations in the intertidal zone. The assemblages were dominated by three species, Haynesina germanica, Ammonia beccarii (forma tepida), and Elphidium excavatum. Patchiness occurred on a scale of a few centimeters and had a major impact on tracking temporal changes in the standing crop. The study clearly shows the need for replicate sampling in order to obtain reliable information especially on absolute abundance data. The absence of juveniles is due to loss through drying the samples prior to picking. The results show that it is not possible to determine the lifespan of continuously reproducing species (i.e., young individuals always present) where it is impossible to follow the growth of cohorts, and for the same reason it is not possible to make production calculations. While there is a cyclicity in standing crop at station 2 (mid intertidal zone), this is not the case at station 1 (lower intertidal zone). Species diversity showed reasonable annual cyclicity at both stations. At neither station is there any correlation between the size of the standing crop and the chlorophyll a content of the surface sediment. There was some cyclicity in the peaks of biomass (only determined for sta. 1) in all three species and considerable variability from one year to the next. Thus this area is extremely variable, there is no obvious annual pattern in standing crop, and the best measures of seasonality seem to be species diversity and biomass. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Zooplankton dynamics in a mesoscale eddy-jet system off California

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 201:165-178 (2000) - doi:10.3354/meps201165 Zooplankton dynamics in a mesoscale eddy-jet system off California M. E. Huntley1,*, A. González1, Y. Zhu1,**, M. Zhou2,**, X. Irigoien3,*** 1Marine Biology Research Division, Scripps Institution of Oceanography, 0202 La Jolla, California 92093-0202, USA 2Physical Oceanography Research Division, Scripps Institution of Oceanography, 0230, La Jolla, California 92093-0230, USA 3Center for Coastal and Marine Science, Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, United Kingdom *Present addresses: *School of Ocean and Earth Science and Technology, University of Hawaii, 1680 East-West Road, Post 802, Honolulu, Hawaii, USA. E-mail: mhuntley@kona.net **Large Lakes Observatory, University of Minnesota, 10th University Dr., Duluth, Minnesota 55812, USA ***George Deacon Division, Southampton Oceanography Centre, Empress Dock, Southampton SO14 3Z4, UK ABSTRACT: Zooplankton in the central jet of the California Current and an adjacent mesoscale cyclonic eddy centered at 125.1°W, 38.4°N were studied in early July, 1993, using a SeaSoar-mounted Optical Plankton Counter. Within 3 d after the 2 d survey of these mesoscale features we completed a MOCNESS transect across the study area. Zooplankton in the rapidly moving (>40 cm s-1 near surface) jet were negatively correlated with the vertical distribution of phytoplankton biomass, which displayed strong fluorescence maxima in the upper 200 m. Zooplankton in the recirculating eddy, however, were positively correlated with fluorescence maxima at the pycnocline (ca 50 m) and at 150 m. Euphausiids, dominated by Euphausia pacifica, and the copepod Calanus pacificus accounted for most of the zooplankton in the upper 50 m of the eddy, while the copepod Metridia pacifica dominated the abundance maximum of medium size zooplankton at 150 m. These species were also present in the jet, but male:female ratios of the 2 copepod species differed greatly, suggesting that populations within the jet and the eddy were distinct from one another. Earlier observations of the cyclonic eddy indicate that it departed California coastal waters in April; resident zooplankton populations may have gone through several generations before they reached the position at which we found it in July. Waters of the jet, by contrast, probably departed from the California coastal region in mid-June, so that its populations of zooplankton may have been essentially the same as those advected to our sampling location. KEY WORDS: Zooplankton · Eddy · Jet · Mesoscale · Dynamics Full article in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 201. Online publication date: August 09, 2000 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2000 Inter-Research.