NaN dbar 0972 20-Feb-14 coordinate sea_water_pressure Pressure due to seawater down -1.000000000000000 12000.00000000000 Z mounted_on_shipborne_profiler NaN Days since 1970-01-01 00:00:00 time Average time of measurements timeS T coordinate NaN degree_Celsius sea_water_temperature Sea water temperature Data manually reviewed good data 5299 08-Sep-20 -3.000000000000000 40.00000000000000 mounted_on_shipborne_profiler ITS-90 physicalMeasurement NaN S m-1 sea_water_electrical_conductivity Seawater electrical conductivity Instrument data that have been converted to geophysical values unknown 3742 10-Sep-20 0.000000000000000 50.00000000000000 mounted_on_shipborne_profiler physicalMeasurement NaN volt Raw signal (voltage) of instrument output by oxygen sensor Instrument data that have been converted to geophysical values unknown 1740 17-Oct-20 0.000000000000000 1000.000000000000 mounted_on_shipborne_profiler physicalMeasurement NaN 1 sea_water_practical_salinity Practical salinity Salinity values have been compared with salinometer measurements from bottle samples from >1000 dbar (n=16). The average offset (CTD minus salinometer) was -0.0038. This was considered within the total margin of error, except for one notable outlier at station sta010_01, where a salinity difference of -0.0164 was found. Removing this offset from the profile brings the bottom temperature-salinity properties closer to the deep water masses further offshore along the same transect. Sta010_01 was also the first profile taken after the unloading operations, during which the CTD package was unsupervised inside a shipping container for several days, where e.g. accretion of salt crystals in the conductivity cell may have led to a time-depended bias when measurements were resumed. However, at this point, we cannot conclude whether the difference at this station is related to a sensor offset or an inaccurate salinometer sample, and no correction was applied to any of the profiles in this file, and with a greater uncertainty to be accounted for at sta010_01. Data manually reviewed good data 5299, 3742 08-Sep-20, 10-Sep-20 2.000000000000000 41.00000000000000 mounted_on_shipborne_profiler PSS-78 physicalMeasurement 14 data points have been removed from this variable based on visual inspection. NaN mL l-1 volume_fraction_of_oxygen_in_sea_water Dissolved oxygen from sensor. Not calibrated against water samples. Not compared with water sample oxygen measurements. Quality unknown! Instrument data that has been converted to physical values unknown 1740 17-Oct-20 0.000000000000000 1000.000000000000 mounted_on_shipborne_profiler physicalMeasurement CTD station ID mounted_on_shipborne_profiler physicalMeasurement profile_id NaN degree_north latitude latitude mounted_on_shipborne_profiler physicalMeasurement Y NaN degree_east longitude longitude mounted_on_shipborne_profiler physicalMeasurement X Cruise ID mounted_on_shipborne_profiler physicalMeasurement NaN mg m-3 chlorophyll_concentration_in_sea_water Chlorophyll-A concentration calibrated against water sample measurements No correction for near-surface fluorescence quenching (see e.g. https://doi.org/10.4319/lom.2012.10.483) has been applied. Post-recovery calibrations have been applied good data chla_calibrated = A * chla_from_ctd + B 0.08950000000000000 -0.09393025000000001 FLRTD-1547 4-Jan-16 -1.900000000000000 100.0000000000000 mounted_on_shipborne_profiler physicalMeasurement Profile *sta013_01* removed from the dataset due to issues with the sensors causing unrealistic values CTD data (temperature, conductivity, salinity, chlorophyll, uncalibrated oxygen) from Troll Transect cruise 2020/21 to Dronning Maud Land, Antarctica CTD data collected off the coast of Dronning Maud Land, Antarctica during the Troll Transect Cruise 2020/21. This dataset contains pressure-gridded (1 dbar) CTD data (temperature, conductivity, salinity, chlorophyll, uncalibrated oxygen) from 14 profiles collected between 28.12.2020 and 07.01.2021. Data were collected using an SBE911+ unit (other CTD data were collected during the cruise - they are not included here). Stations from 010_01 constitute a meridional (offshore) transect along approximately 6.1\302\260E. Data from an SBE 43 oxygen sensor are included (both as dissolved oxygen and raw sensor voltage) - please note that these data have not been calibrated or quality-controlled, and are provided as-is. CTD Chlorophyll data were calibrated based on a linear fit of CTD fluorometer against bottle fluorescence measurements: 1. First, the median value of dark counts at depth was determined based on measurements from 100 to 500 m depth. 2. A visual inspection confirmed that there were no offsets between profiles. 3. To calibrate the bottle Chl-a data to the bottle fluorescence measurements, we first only considered the bottle Chl-a value when the standard deviation of the bottle value divided by the fluorescence measurement was < 0.15, to avoid highly noisy parts of the fluorescence profile. Then we subtracted the offset value (1.0495) from the bottle fluorescence measurement, then we fit a linear regression with the bottle Chl-a measurement. Salinity values have been compared with salinometer measurements from bottle samples from >1000 dbar (n=16). The average offset (CTD minus salinometer) was -0.0038. This was considered within the total margin of error, except for one notable outlier at station sta010_01, where a salinity difference of -0.0164 was found. Removing this offset from the profile brings the bottom temperature-salinity properties closer to the deep water masses further offshore along the same transect. Sta010_01 was also the first profile taken after the unloading operations, during which the CTD package was unsupervised inside a shipping container for several days, where e.g. accretion of salt crystals in the conductivity cell may have led to a time-depended bias when measurements were resumed. However, at this point, we cannot conclude whether the difference at this station is related to a sensor offset or an inaccurate salinometer sample, and no correction was applied to any of the profiles in this file, and with a greater uncertainty to be accounted for at sta010_01. 2020-12-28 to 2021-01-07: Data collection. 2021-01-13 to 2021-01-21: Processed to .cnv using SBE software (details in "SBE_processing"). 2023-12-29: Post-processing. 2024-01-22: Creation of this netcdf file. TrollTransectCTD_2020_2021_v1 1.0 10.21334/npolar.2023.b1504a66 2024-01-22T14:16:27Z Chlorophyll-a profiles calculated based on best fit against in-situ water sample measurements (see CHLA attributes for details). Oxygen NOT calibrated against water sample measurements. CTD profiles from SBE911+ In Situ/Laboratory Instruments>Profilers/Sounders>CTD Water-based Platforms>Vessels Norwegian Polar Institute (NPI) TrollTransect Cruise 2020/2021 Norwegian Polar Institute 2020/21 TrollTransect pilot project cruise; Ocean-ice shelf interaction and channelized Melting in Dronning Maud Land project, Research Council of Norway grant no. 295075 Southern Ocean Kong H\303\245kon VII Hav / Dronning Maud Land (DML) CC-BY 4.0 2020-12-28T09:19:47Z 2021-01-07T10:59:14Z variable P0000-00-10T01:39:27 -67.01620000000000 10.62470000000000 -70.01220000000001 5.514700000000000 POLYGON ((5.51 -70.02, 5.51 -67.01, 10.63 -67.01, 10.63 -70.02, 5.51 -70.02)) EPSG:4326 2.000000000000000 3403.000000000000 down dbar EPSG:5831 eng NO/NPI Norwegian Polar Institute (NPI) post@npolar.no institution Norwegian Polar Institute (NPI) www.npolar.no Norwegian Polar Institute (NPI) www.npolar.no post@npolar.no Norwegian Polar Institute (NPI) OCEANS>OCEAN TEMPERATURE>OCEAN TEMPERATURE PROFILES,OCEANS>OCEAN CHEMISTRY>OXYGEN,OCEANS>SALINITY/DENSITY>OCEAN SALINITY>OCEAN SALINITY PROFILES,OCEANS>SALINITY/DENSITY>CONDUCTIVITY>CONDUCTIVITY PROFILES,OCEANS>OCEAN OPTICS>CHLOROPHYLL>CHLOROPHYLL CONCENTRATION 1 decibars (SBE software) SBE SOFTWARE PROCESSING STEPS (extracted from .cnv file header): 1. Raw data read from e.g. STA018_01.HEX, STA018_01.XMLCON. 2. Oxygen hysteresis correction applied. 3. Wild editing applied. > Parameters: n_std (first pass): 2.0, n_std (second pass): 20.0, min_delta: 0.0, > # points per test: 100.0. > Applied to variables: prDM t090C c0S/m. 4. Cell thermal mass correction applied to conductivity from sensors: [primary, ]. > Parameters ALPHA: [0.0300, 0.0000], TAU: [7.0000, 0.0000]. 5. Low-pass filter with time constant 0.03 seconds applied to: t090C c0S/m sbeox0V flECO-AFL altM. 6. Low-pass filter with time constant 0.15 seconds applied to: prDM. 7. Loop editing applied. > Parameters: Minimum velocity (ms-1): 0.250, Soak depth range (m): 5.0 to 20, > Bad scans excluded. Deck pressure offset: Yes. 8. Derived EOS-8 salinity and other variables. 9. Bin averaged (1 decibars). > Bad scans not excluded, skipped over 0 initial scans. > (No surface bin). E.g. STA018_01.HEX, STA018_01.XMLCON -> STA018_01.CNV profile CF Standard Name Table v83 NASA/GCMD Instrument Keywords Version 17.2 NASA/GCMD Science Keywords 9.1.5 oceans ACDD-1.3, CF-1.8 npolar.no Malik Arctica Norwegian Polar Institute Antarctic Porgram, Research Council of Norway POLARPROG Data collection and processing was a part of the Norwegian Polar Institute 2020/21 TrollTransect pilot project cruise and supported by the Ocean-ice shelf interaction and channelized Melting in Dronning Maud Land project, Research Council of Norway grant no. 295075 complete