Attention:
Please note that operations of the CTD (Conductivity-Temperature-Depth) watersampler requires experienced scientific staff on board. The system is not operated by the ship's crew. Announce operations with the CTD watersampler to AWI-Logistics prior to the cruise and clarify the data transfer after the cruise.
Summary
The CTD probe measures conductivity and temperature along a vertical transect through the water body. The measured parameter are used to calculate the salinity of the water. Additionally, up to 24 water samples can be taken in different water depths during the CTD measurements. A fluorometer, an oxygen sensor and a transmissiometer are attached to the CTD as well. The system is operational up to 2000m water depth.
| Manufacturer | Seabird |
|---|---|
| Model | SBE911plus mit SBE32 |
| Serial No. | n/a |
| Type | CTD |
Contacts
| Name | Institution | Role |
|---|---|---|
| Gerd Rohardt | Alfred-Wegener-Institute | Data Scientist |
| Andreas Wisotzky | Alfred-Wegener-Institute for Polar and Marine Research | Data Scientist |
Components
The CTD system consists of the underwater unit SBE 9plus, the deck unit SBE 11plus V2 and the carousel water sampler SBE32 which is equipped with free flow water samplers manufactured by Hydro-Bios. The CTD is outfitted with a double set of temperature (SBE 3plus) and conductivity (SBE 4C) sensors that are calibrated regularly. Additionally, an altimeter, a transmissometer, an oxygen sensor and a fluorometer may be attached to the CTD unit and operated to water depths of 6000m.
On the CTD data aquisition PC in the Messraum following software is installed: aquisition software Seasave (Version V7_19), SBE Data processing software, ManageCTD software packet for cleansing and conversion of the data and Ocean Data View (ODV) for visualization.
| Name | Model | Type |
|---|---|---|
| PSA-916 Sonar Altimeter | PSA-916 | altimeter |
| SBE32 water sampler | SBE32 | remote water sampler |
| SBE3plus temperature sensor | SBE3plus | temperature sensor |
| SBE4 conductivity sensor | SBE4 | conductivity meter |
| SBE43 oxygene sensor | SBE43 | oxygen sensor |
| C-Star transmissometer | C-Star | transmissometer |
| ECO FL fluorometer | ECO FL | fluorescence Sensor |
| SBE 5P pump | SBE 5P | pump |
Position
| Origin Description: | The CTD unit is usually stored on the main deck. Electronics and the computer for operation are installed in the Mess- und Registrierraum. |
Data logging, storage and archiving
Logged parameters
| Parameter | Sensor Output Type | Unit |
|---|---|---|
| conductivity | conductivity | S/m |
| water temperature | water temperature | °C |
| oxygen content | oxygen | ml/l |
| pressure | pressure | dbar |
| fluorescence | fluorescence | V |
| distance to sea floor | distance | m |
| transmission | transmission | % |
Central geographical ship's position and time standard
The PC is time synchronised via the Windows-Domain-Affiliation. Geographic position and UTC time is made available to the system via NMEA telegram and read by Seasave software.
Rawdata storage on board
Raw data are stored with the ManageCTD software on the aquisiton PC in following data structure:
| root directory | \\xdc\scientists\data\CTD\ |
| directory name | CruiseNo e.g. HE507 with subdirectories |
| data volume (MB per day) ca. | 50 |
| number of files per day ca. | 10 |
Data archiving on land
After consultation with the data scientist and AWI Logistics the CTD data including meta data may be transferred to PANGAEA (https://www.pangaea.de/).