Bottle Data Research Articles

Lagrangian circulation and forbidden zone on the West Florida Shelf

This paper presents some recent results of drifters released on the West Florida Shelf during 1996–1997 and compares with the numerical model results of the wind-driven circulation. Using satellite tracked surface drifters during the one year period from February 1996 to February 1997, a drifter free region, called the “forbidden zone”, is found over the southern portion of the West Florida Shelf. This finding is consistent with historical drift bottle data and with a recent numerical model study of the West Florida Shelf circulation response to climatological wind forcing. Direct drifter simulations by numerical model during March 1996 show a good agreement with both the in situ ADCP current observation and drifter observation. Three mechanisms are proposed for the observed Lagrangian features. The primarily dynamic mechanism is the along-shore wind forcing, which induces a coastal jet that tends to leave the coast and the bottom onshore and near surface offshore transports. The second one is the convergent coastal geometry and bottom topography for the southward flow in central shelf near Tampa Bay that enforces the coastal jet and the bottom and near surface transport. The last is a kinematic one, simply due to the short along-shore Lagrangian excursion, driven by the typical synoptic weather systems. Thus near surface shelf waters over the north may not reach the southern coast of the West Florida. Implication is that surface hazard such as oil spill that may occur outside of the southern West Florida shelf may not greatly impact the southern coastal region except Florida Keys. However, the biological and chemical patches over the north that may occur in the water column such as red tides still can easily reach the southern coastal region through the subsurface and bottom waters.

Three‐dimensional isoneutral potential vorticity structure in the Indian Ocean

The three‐dimensional isoneutral potential vorticity structure of the Indian Ocean is examined using World Ocean Circulation Experiment and National Oceanic and Atmospheric Administration conductivity‐temperature‐depth data and historical bottle data. The distribution of the potential vorticity is set by the Indian Ocean's source waters and their circulation inside the basin. The lower thermocline has a high potential vorticity signal extending westward from northwest of Australia and a low signal from the Subantarctic Mode Water in the south. The Antarctic Intermediate Water inflow creates patches of high potential vorticity at intermediate depths in the southern Indian Ocean, below which the field becomes dominated by planetary vorticity, indicating a weaker meridional circulation and weaker potential vorticity sources. Wind‐driven gyre depths have lower potential vorticity gradients primarily due to same‐source waters. Homogenization and western shadow zones are not observed. The β‐effect dominates the effect of the Somali Current and the Red Sea Water on the potential vorticity distribution. Isopleths tilt strongly away from latitude lines in the deep and abyssal waters as the Circumpolar Deep Water fills the basins in deep western boundary currents, indicating a strong meridional circulation north of the Antarctic Circumpolar Current. The lower‐gradient intermediate layer surrounded vertically by layers with higher meridional potential vorticity gradients in the subtropical Indian Ocean suggests that Rossby waves will travel ∼1.3 times faster than standard theory predicts. To the south, several pools of homogenized potential vorticity appear in the upper 2000 m of the Southern Ocean where gyres previously have been identified. South of Australia the abyssal potential vorticity structure is set by a combination of the Antarctic Circumpolar Current and the bathymetry.

Is the Arctic Ocean warming?

Recent high‐quality hydrographic measurements in the Arctic Ocean have revealed a warming of up to 1 K of the Atlantic Layer when compared with Russian climatologies of the 1940s to 1970s. About half of this warming can be attributed to the different methods by which the two data sets were obtained: the climatologies are based on discrete bottle data in the vertical and necessarily involve smoothing in space and time, whereas the modern, quasi‐synoptic data are from continuously recording conductivity‐temperature‐depth sondes and give much better resolution in the vertical. Modern surveys also focused more on boundary current regimes where narrow warm bands of Atlantic Water are present. The remainder of the warming detected can be explained with the following physical arguments: (1) an increased inflow of Atlantic Water in the early 1990s and (2) a higher temperature of this inflowing water. Temperature time series in the Barents Sea since the beginning of this century suggest that the warming of the early 1990s is not a long‐term climate signal but, rather, is related to the inherent natural variability of the system with timescales of decades.

Estimation of total C0 2 concentration throughout the water column

We use total C02 data sets measured on the recent Joint Global Ocean Flux Study (JGOFS) and World Ocean Circulation Experiment (WOCE) cruises to investigate potential parameterizations of TC0 2 data sets. The observed temporal variations of TC0 2 in surface seawater were large (4% of the signal within a month) compared to the relatively small spatial variations (< 2% over 10 degree latitude). Yet the result of our study suggests that a single sigmoid function of the form TCO 2(x) = a 1 − b 1 [1 + e −(c 1(x−d 1)) ] e 1 + b 1 can be used to fit, parameterize, and interpolate closely (within the accuracy of the measurement) each upper ocean (< 250 m) TCO 2-depth profile of the temporal and spatial data sets from the North Atlantic and Equatorial Pacific Oceans that we examined. This sigmoid function is not specific to TCO 2 data sets, and it could probably be used over most (if not all) of the upper ocean to fit, parameterize, and interpolate physical and chemical oceanic data sets. Below the upper layer (depth > 250 m) TCO 2 can be parameterized by the relationship TCO 2 = a + bΘ + c AOU + dS where Θ, AOU, and S represents potential temperature, apparent oxygen utilization and salinity, respectively. The coefficients a, b, c, and d are experimentally determined by multiple linear regression using discrete bottle data from depths below the wintertime mixed layer depth. Densely sampled CTD data of temperature, salinity, and oxygen can then be used to interpolate TCO 2 data at non-sampled depths. The two parameterized functions describing TCO 2 in and below the upper ocean can further be blended at the wintertime mixed layer depth to yield a continuous estimate of TCO 2 concentration throughout the water column.

Distribution and Formation of North Pacific Intermediate Water

The North Pacific Intermediate Water (NPIW), defined as the main salinity minimum in the subtropical North Pacific, is examined with respect to its overall property distributions. These suggest that NPIW is formed only in the northwestern subtropical gyre; that is, in the mixed water region between the Kuroshio Extension and Oyashio front. Subsequent modification along its advective path increases its salinity and reduces its oxygen. The mixed water region is studied using all bottle data available from the National Oceanographic Data Center, with particular emphasis on several winters. Waters from the Oyashio, Kuroshio, and the Tsugaru Warm Current influence the mixed water region, with a well-defined local surface water mass formed as a mixture of the surface waters from these three sources. Significant salinity minima in the mixed water region are grouped into those that are directly related to the winter surface density and are found at the base of the oxygen-saturated surface layer, and those that form deeper, around warm core rings. Both could be a source of the more uniform NPIW to the east, the former through preferential erosion of the minima from the top and the latter through simple advection. Both sources could exist all year with a narrowly defined density range that depends on winter mixed-layer density in the Oyashio region.

A deep boundary current in the Arabian Basin

Recently collected CTD data are supplemented by historical Nansen bottle data to examine the circulation of bottom water in the Arabian Basin. A deep western-boundary current is observed flowing southeastward below a mid-depth zero-velocity surface along the Carlsberg Ridge. A zero-velocity surface at potential isotherm 1.7°C in chosen on the basis of water-mass properties. However, the origin of the bottom water in the Arabian Basin cannot be determined in a like manner. The bottom water could enter from the Somali Basin through the Owen Fracture Zone, or from the Central Indian Basin through passages in the Chagos-Laccadive Ridge south of the equator. Application of the Stommel-Arons framework for deep-circulation dynamics to the basin suggests that the bottom water is supplied primarily through the Owen Fracture Zone.

Measuring Compliance-Reply

In Reply.— Mr Hoar has expressed concern about medication compliance in geriatric and retarded populations that were not addressed in our study. We observed medication-taking practices in adult patients with epilepsy (aged 18 through 68 years) of borderline to superior intelligence (IQ, 76 to 124) to assess compliance in a broad range of relatively normally functioning persons. Use by low-functioning patients is feasible, but has not been evaluated. The cost for Medication Event Monitoring Systems bottle rental ($7 per month) and a report ($56) is in the range of cost for a laboratory drug serum concentration test. As explained in the article, the Medication Event Monitoring Systems device counts presumptive doses. Indeed, this prototype device does not verify pill swallowing. The software developed by the Aprex Corporation (Fremont, Calif) to analyze Medication Event Monitoring Systems bottle data can filter excess, sequential openings. In addition, calendar plots showing missed doses and

Sargasso sea reference curves for salinity, potential temperature, oxygen, nitrate, phosphate, and silicate as functions of sigma-theta

Empirical relationships of salinity, potential temperature, oxygen, nitrate, phosphate, and silicate as functions of σ θ have been obtained for a set of Sargasso Sea stations sampled during 1977. The relationships were determined by fitting the data with a cubic-spline function using the minimum number of knots (intervals) that would adequately describe the data. Salinity, potential temperature, and oxygen functions were derived from continuous CTD data over the σ θ range 26.00 to 27.88. The cubic-spline functions for nitrate, phosphate, and silicate cover the smaller range 26.32 to 27.91, due to the sparsity of the discrete bottle data at lower σ θ values. Property anomalies vs σ θ were obtained for several Gulf Stream and Slope Water stations by subtracting the Sargasso Sea cubic-spline functions from observed profiles. The salinity, potential temperature, and oxygen anomaly plots show features characteristic of each of the two areas. The nutrient anomaly plots for the Gulf Stream and Slope Water show only small variations relative to the Sargasso Sea Water reference curves.

Global ocean data inventory and climate data base

In response to a request by the United Nations Intergovernmental Oceanographic Commission (IOC) for member states to provide data management services for oceanographic data collected during the First Garp Global Experiment, (FGGE), also known as the Global Weather Experiment, the Environmental Data and Information Service of NOAA (EDIS) will serve as a Responsible National Oceanographic Data Center for the FGGE Operational Year (RNODC‐FOY. In this capacity, EDIS will (1) develop a global inventory of all ocean data collected during FOY and (2) create a global ocean climate data base of selected FOY physical oceanographic parameters. All data will be exchanged through normal international exchange channels.The global ocean data inventory will contain directory information regarding all known oceanographic data of any kind recorded during FOY (December 1, 1978 through November 30, 1979). The inventory will be available both in published form and online to computer terminal users internationally via either Tymnet or Telenet. The global ocean climate data base will include physical oceanographic data for this same period acquired by the RNODC‐FOY. Bathythermograph data, Nansen/Nisken bottle data, salinity‐temperature‐depth data, and current meter data, as well as phosphate, silicate, oxygen, and sea level data will be formated and quality controlled.

Photosynthetic rates in Lake Superior

SummaryThree methods of measuring carbon fixation rates in Lake Superior were employed during a July 26—August 8, 1973 cruise on Lake Superior: (a) 14C-uptake in clear vs dark bottles(b) Δ pH in clear vs dark bottles and(c) pH-depth profiles comparing early morning versus late afternoon data, to compute diurnal Δ pH in the upper 50 meters of water. The photosynthetic yields revealed large discrepancies among these three methods. If one assumes that clear vs. dark bottle data represents the average yield in the euphotic zone (36 meters) and that the photoperiod is 14 hours then method (a) yields 14 millimoles/m2/day, (b) yields 111 and (c) yields 200. Because practically all Lake Superior productivity data in the literature are based on 14C data, it seems likely that the estimates of the degree of oligotrophy of Lake Superior have been biased by the low photosynthetic yields obtained by this method.

Evidence for trans-Atlantic transport of gastropod larvae belonging to the genus Cymatium

Many tropical and semi-tropical species of gastropods are geographically distributed in a manner such as to suggest that their larvae may be transported across the ocean. Direct evidence from plankton tows shows that veliger larvae, probably referable to Cymatium parthenopeum (von Salis), are commonly found throughout the Gulf Stream and North Atlantic drift. The average rate of transport of surface waters between the Bahamas and the Azores, computed from drift-bottle records, is 0·4 knots. Living veliger larvae caught in plankton samples were kept in the laboratory for a period longer than that required for their transport in the Gulf Stream to the eastern Atlantic. The distribution of C. parthenopeum in the western Atlantic extends from the coast of Brazil northward, throughout the West Indies, to Bermuda; in the eastern Atlantic it ranges from the Azores and the western Mediterranean southward along the west coast of Africa to the Cape of Good Hope. This distribution could be accounted for by transport of veliger larvae in the warm currents of the North Atlantic. Computations based on drift bottle data and from estimates of larval survival show that trans-Atlantic drift of veliger larvae is probably a common phenomenon. If the estimates are reasonably correct, considerable gene flow must occur between the populations of the western and eastern Atlantic.

PHYTOPLANKTON COMMUNITIES OF WESTERN LAKE ERIE AND THE CO2 AND O2 CHANGES ASSOCIATED WITH THEM

Phytoplankton studies using samples concentrated by settling revealed population densities several times higher than those reported previously, based on centrifuge and bolting cloth concentrates. Clear and dark bottle experiments employing natural population densities revealed photosynthetic yields averaging 1.6 µmoles of CO2 absorbed per microliter of plant volume per hour. This yield is three times higher than previously reported yields based on artificially concentrated populations. Comparison of daily photosynthetic yields per square meter of water as computed from bottle data with yields measured under completely natural conditions indicated an additional twofold discrepancy, with the natural condition yielding the higher value. The reduction of turbulence in bottles may be operating to reduce the photosynthetic yield. Eddy diffusivity in western Lake Erie, computed from pH change in the dysphotic zone, and vertical pH gradients, is about 25 cm2/sec. Simultaneous determinations of CO2 and O2 changes showed that O2 changes usually were lower than CO2 changes, suggesting that processes other than photosynthesis are influencing the CO2 and O2 budgets.