Conductivity, temperature and depth

CTD and Data Logging. A digital CTD unit (Model 8705, Guildline Instruments Ltd., Smith Falls, Ontario, Canada) mounted on the Batfish see Figure 1) measures in situ conductivity, temperature, and depth (CTD) with accuracies of 0.01 ppt, 0.01 °C, and 1 dbar (full scale... 

The data presented are for samples collected by using a pump-profiling system designed to minimize atmospheric contamination. This pump sampler was attached at the end of a 400-m electrical cable with a conductivity, temperature, and depth device (CTD, Seabird SBE-9/11). The nylon hose was interfaced to an autoanalyzer for detailed analyses of N03 , N02 , NH4+, H4Si04, PO,3, and H2S. Discrete samples were taken for oxygen, manganese, and iron. 

Surface sediment samples were collected from Loch Sunart, a sea loch (fjord) on the NW coast of Scotland, during cruises aboard the R. V. Clupea (April 1999) and the R. V. Envoy (July 2001 and June 2002). Bottom water temperature and salinity measurements were recorded using a STD Plus 646 conductivity, temperature and depth (CTD) probe at each sample site (Table 1). No data were collected on pH and carbonate ion concentration. Two stationary Anderaa RCM-7 current meters complete with temperature and conductivity sensors and a data logger were deployed in the inner basin (56.6842°N, -5.6211°W) between 21 June 2001 and the 18 June 2002, and the main... 

Salinity-Temperature-Pressure (Depth). Conductivity, temperature and pressure data were collected using a Plessey Systems CTD with model 8400 data logger. These sensors were interrogated five times per second for values of temperature, conductivity (salinity), and pressure (depth). Data were recorded during the down-cast using a lowering rate of 30 m min". Niskin bottle samples were taken on every other cast to provide temperature and salinity calibration. Nominal precision of the salinity, temperature and depth measurments was 0.02 g kg", 0.02 °C and 0.2 m, respectively. 

Instruments, termed CTD, are available for the in situ measurements of conductivity, temperature and pressure (and derived depth). However, as temperature and pressure values change in situ, Eq. (3-4) cannot be used directly to calculate S. Additional relationships are needed to link S to the entire oceanic temperature and pressure ranges. Let... 

Table 6.14 Effects of Temperature and Depth of Discharge (DOD) on Thermal Conductivity of Electrolytes...

Currents can be measured at single-points in the water column by a propeller-type current meter (with a vane to also allow measuring directions) or by electromagnetic flowmeter (so-called ECM s or DRCM s). The instruments can also be combined with CTD s to measure conductivity, temperature and water depth (see further below). 

Fig. 5. Variation of the Sl80 and 8D values of the fluid delivered from well 131, located 500 m away from the re-injection site, during an injection test conducted in the peripheral area of Serrazzano in the Larderello field (open squares). The figure also shows graphically, and in arbitrary units, the flow rate Q of water re-injected into the well as a function of time, and the position of each sample collected. Theoretical isotopic pattern of the steam produced by re-injected water, assuming continuous steam separation at depth, is also reported. Since the actual evaporation temperature and the fraction of residual water are unknown, calculations were made for three different temperatures (140, 160, and 180 °C) and fractions (/w) of residual liquid water after boiling. Dashed line represents the hypothetical mixing between deep geothermal steam (W) and completely evaporated re-injected water (R).

The deep-water observations with conductivity, temperature, depth (CTD) profilers performed in the Black Sea during the past two decades allowed one to distinguish the near-bottom mixed layer (NBML). In Fig. 3b, we present profiles of the potential temperature (T ), salinity (S), and potential density (ct ) of the Black Sea waters in the layer from 1500 to 2100 m obtained by averaging of 46 CTD profiles observed in 1985-1992 in different regions of the deep-sea area. In all three profiles shown in Fig. 3b, a distinct upper boundary of the NBML is traced at depths from 1750 to 1800 m. Above it, up to a depth of 1700 m, one finds a layer with increased vertical gradients of T , S, and a with a thickness about 100 m it separates NBML from the deep stratified layer. 

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