Physical and chemical profile data collected from CTD aboard the R/V Endeavor during the cruise EN492 in the North Atlantic Ocean from 2011-04-26 to 2011-05-20 (NCEI Accession 0100255)
공공데이터포털
The dataset consists of 115 CTD casts in the region north of Flemish Cap. Some casts cover the full water column, while others only cover the upper 1000 db. The CTD casts were obtained with a SeaBird SBE911+ system, measuring temperature (2 sensors), conductivity (2 sensors), pressure, beam transmission, height above the bottom, oxygen (2 sensors), and chlorophyll fluorescence. All sensors were sampled at 24 Hz. The data were processed using the SeaBird data processing software suite, SBEDataProcessing-Win32, and with software in MATLAB. A low pass filter, with time constant of 0.15 s, was applied to the pressure record. To account for the transit time between the temperature and conductivity sensors, the conductivity measurements were aligned with the temperature measurements using empirically determined time delays. The primary conductivity was delayed by 0.035 s relative to pressure (this is in addition to the advance of 0.073 s which is performed by the SeaBird deckbox during data acquisition, thus resulting in a net advance of 0.038 s). The secondary conductivity was advanced by 0.048 s (except for cast ctd001, which had the automatic deckbox advance value of 0.073 s applied. Thus the secondary conductivity from this cast was delayed by 0.025 s, giving a net advance of 0.048 s). The two oxygen voltages were advanced by 4 s relative to pressure. A correction for conductivity cell thermal mass effects was applied to both conductivity channels using the parameters recommended by SeaBird (alpha=0.03, 1/beta=7.0). The temperatures, conductivities, and oxygen voltages were then median filtered using a 7-scan window. A loop edit step was then applied, whereby portions of the cast in which the pressure was not changing sufficiently fast (0.2 dbar/s) were removed. This was followed by computation of salinity, potential temperature, potential density, sound velocity, geopotential anomaly, and oxygen concentration. Unfortunately, it was found that the SeaBird data processing module Derive used the primary temperature and salinity in computing both primary and secondary oxygen. Because there were several casts during which the primary temperature sensor intermittently failed, this resulted in loss of oxygen data. To get around this problem, the oxygen calculation was performed separately in MATLAB using the SeaBird algorithm and with primary/secondary oxygen computed using primary/secondary T and S respectively. Finally, the data from the downcast were averaged into 1 dbar bins. Further details of the CTD data processing can be found in the header portion of the individual cast files. The final data files contain raw sensor values (1 dbar bin averages) plus a number of derived variables (e.g., potential temperature, salinity, sigma-theta, oxygen). A full list of the output variables is contained in the header portion of the cast files. The casts were visually examined to determine the quality of the data from the 2 separate sensor suites (primary and secondary). A header line was placed in each file indicating the preferred sensor pair (PRIMARY or SECONDARY) if one was bad or whether both were of equal quality (BOTH GOOD).
Oceanographic profile temperature and salinity data using underway CTD, collected by the Graduate School of Oceanography, University of Rhode Island, cruise EN492, North Atlantic Ocean, 2011-04 to 2011-05 (NCEI Accession 0116845)
공공데이터포털
The dataset consists of 79 Underway CTD (UCTD) casts in the region north of Flemish Cap. The UCTD is an un-pumped profiling CTD, manufactured by the Oceanscience Group, that can be deployed from a moving ship. The UCTD measures temperature, conductivity, and pressure at 16 Hz. The pressure and its time derivative (descent rate) were low-pass filtered with a filter cutoff period of 2 s. The temperature and conductivity signals were also filtered, but with the filter cutoff period set to 0.25 s. Alignment of the temperature and conductivity was performed as a function of the instrument descent rate using an empirical relationship. Because of the rapid descent rate of the UCTD (up to 4 dbar/s), the measured temperature was corrected for the effect of viscous heating. The effect of the thermal mass of the conductivity cell was accounted for using the standard correction with the parameters determined as a function of the local instrument descent rate. The processed temperature, conductivity, and pressure were used to compute salinity, potential temperature, and potential density. Finally, the data were averaged into 1 dbar bins.
Oceanographic profile temperature and salinity data using underway CTD, collected by the Graduate School of Oceanography, University of Rhode Island, cruise KN200-2, North Atlantic Ocean, 2011-03 (NCEI Accession 0115494)
공공데이터포털
The dataset consists of 81 Underway CTD (UCTD) casts in the region north of Flemish Cap. The UCTD is an un-pumped profiling CTD, manufactured by the Oceanscience Group, that can be deployed from a moving ship. The UCTD measures temperature, conductivity, and pressure at 16 Hz. The pressure and its time derivative (descent rate) were low-pass filtered with a filter cutoff period of 2 s. The temperature and conductivity signals were also filtered, but with the filter cutoff period set to 0.25 s. Alignment of the temperature and conductivity was performed as a function of the instrument descent rate using an empirical relationship. Because of the rapid descent rate of the UCTD (up to 4 dbar/s), the measured temperature was corrected for the effect of viscous heating. The effect of the thermal mass of the conductivity cell was accounted for using the standard correction with the parameters determined as a function of the local instrument descent rate. The processed temperature, conductivity, and pressure were used to compute salinity, potential temperature, and potential density. Finally, the data were averaged into 1 dbar bins.
Physical and chemical profile data collected from CTD in the R/V Knorr cruise KN200-2 during March 2011 in the North Atlantic Ocean (NCEI Accession 0100287)
공공데이터포털
The dataset consists of 100 CTD casts in the region north of Flemish Cap. Some casts cover the full water column, while others only cover the upper 1000 db. The CTD casts were obtained with a SeaBird SBE911+ system, measuring temperature (2 sensors), conductivity (2 sensors), pressure, beam transmission, oxygen (plumbed in series with the primary T/C sensor pair), chlorophyll fluorescence, and turbidity. All sensors were sampled at 24 Hz. The data were processed using the SeaBird data processing software suite, SBEDataProcessing-Win32. A low pass filter, with time constant of 0.15 s, was applied to the pressure record. To account for the transit time between the temperature and conductivity sensors, the conductivity measurements were aligned with the temperature measurements using empirically determined time delays. The primary conductivity was delayed by 0.011 s relative to pressure (this is in addition to the advance of 0.073 s which is performed by the SeaBird deckbox during data acquisition, thus resulting in a net advance of 0.062 s). The secondary conductivity was advanced by 0.050 s. The oxygen voltage was advanced by 4 s relative to pressure. A correction for conductivity cell thermal mass effects was applied to both conductivity channels using the parameters recommended by SeaBird (alpha=0.03, 1/beta=7.0). The temperatures, conductivities, and oxygen voltage were then median filtered using a 7-scan window. A loop edit step was then applied, whereby portions of the cast in which the pressure was not changing sufficiently fast (0.2 dbar/s) were removed. This was followed by computation of salinity, potential temperature, potential density, sound velocity, geopotential anomaly, and oxygen concentration. Finally, the data from the downcast were averaged into 1 dbar bins. Further details of the CTD data processing can be found in the header portion of the individual cast files. The final data files contain raw sensor values (1 dbar bin averages) plus a number of derived variables (e.g., potential temperature, salinity, sigma-theta, oxygen). A full list of the output variables is contained in the header portion of the cast files. The casts were visually examined to determine the quality of the data from the 2 separate sensor suites (primary and secondary). A header line was placed in each file indicating the preferred sensor pair (PRIMARY or SECONDARY) if one was bad or whether both were of equal quality (BOTH GOOD).