Sruise Report, RV ATAIR, Cruise 0671013-1, Bremerhaven —- Skagen - Aberdeen, 19 Jul — 11 Aug 2022 | 15 
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Near-Realtime Processing of CTD Data 
All CTD data have been recorded at an original resolution of 24 Hz. Data have been checked 
and pre-processed during the cruise using the SeaBird SBE Data Processing software, version 
7.26.7.129. The preliminary data taken from the downcast of each CTD profile were binned at 
1 dbar resolution and sent on a daily basis during the cruise in near-real-time to the Maritime 
Data Centre at BSH, Hamburg, Germany and there were uploaded to the CrossDataPortal 
(https://cdp.srx.bsh.de), the open data portal of BSH, from where the data are available to the 
vublic. In total, near-realtime data for 95 CTD profiles were submitted and published during the 
zruise. Pre-processing of the data showed a better performance of the TC1 sensor pack for 
most of the cruise. 
Pre-processing revealed different behaviour from conductivity sensors 1 and 2 at a depth of 
45-65 dbar in profile #068/GN045A. While conductivity sensor 2 produced similar results dur- 
ing the downcast and upcast, conductivity sensor 1 showed enhanced conductivity (and there- 
fore enhanced salinity) during the downcast only, a result that could not be replicated during 
the upcast. The oxygen sensor attached to pump 1 showed reduced oxygen concentrations 
within the same depth range during the downcast. It is most likely that pump 1 sucked in bio- 
logical material, which became stuck in sensor package 1 before it could be flushed out at a 
greater depth. Consequently, conductivity (salinity) data from sensor package 2 was used, and 
oxygen data was removed from the near-real-time data for profile #068/GNO045A. 
5.7 Post-Cruise Processing of CTD Data 
Post-cruise comparisons were made between CTD sensor packs TC1 and TC2. Furthermore. 
a comparison between CTD salinities and AUTOSAL-derived salinities was performed (com- 
pare Table 5.3 and Figures 5.3 and 5.4). 
The following correction procedure is applied to temperatue and conductivity/salinity measure- 
ments as well as oxygen data: 
Assumed measurement accuracy: T-CTD: + 0.002, C-CTD: + 0.003, S: estimated: + 
3.004 
A temperature correction will be applied in case the difference between temperature 
sensors T1 and T2 exceeds 2x 0.002. 
A conductivity correction will be applied in case the salinity difference (AUTOSAL vs 
STD) exceeds 0.003 and/or the difference between conductivity sensors C1 and C2 
3xceeds 2x 0.003. 
The random error of oxygen samples obtained from titration is approximately 1%. 
SCorrections are made if the oxygen difference (bottle vs. CTD oxygen) exceeds 1%.