Topic outline

  • KEIRI Imai, KENJI Oguma, and KOUKI Sawada, Oshoro-maru Marine Science Department, School of Fisheries Sciences, Hokkaido University

  • CTD water sampling system

     The CTD water sampling system is a combination of a wired CTD, a water sampling device, and a water sampler. It is an observation system that measures the vertical distribution of water temperature and salinity, and collects seawater from any layer while monitoring the measured values.


    Fig 1 CTD observation (CTD water sampling system submersible station is being deployed into the sea)

  • Configuration of CTD water sampling system

    The system consists of an underwater station that combines a CTD sensor and a water sampling device, an onboard station (a deck unit that receives data sent from the underwater station and a data recording PC that records and displays data received by the deck unit), and cables connecting them (Figure 2, 3, 4, 5). The underwater station is lifted above the sea surface using a crane, and then lowered into the sea by unrolling a special cable called an armored cable (coaxial cable covered with steel wire) wound on a winch. The values measured by the underwater station are immediately transmitted to the deck unit via the armored cable. The measurement data received by the deck unit is stored in a data recording PC and simultaneously monitored using dedicated software. In addition, the Niskin water sampler lid can be closed by emitting a water sampling signal from the onboard station to collect a seawater sample from any layer.

    CTD採水システム 構成図

    Fig 2 CTD water sampling system Configuration

    船上局 Onboard operation section
    データ収録PC Data recording PC
    デッキユニット Deck Unit
    船内配線 Wiring on board

    CTDウィンチ CTD Winch
    アーマードケーブル armored cable

    水中局 In-water section
    ニスキン採水器 Niskin water sampler
    採水装置 Water sampling equipment
    フレーム Frame

    CTD採水システム 船上局

    Fig 3 Configuration of CTD onboard station

    デッキユニット Deck Unit

    水中局へ To the In-water section

    データ収録PC Data recording PC

    入出力機器(モニタ,キーボード,マウス) Input/output devices (monitor, keyboard, mouse)

     Onboard stations consist of deck units, data recording PCs, monitors, and other input/output equipment. The photo shows the CTD operation room of the training ship Oshoro Maru (Hokkaido University), where two deck units and two data recording PCs are housed in a rack, and monitors and keyboards are installed right next to them.

    CTD採水システム  水中局

    Figure 4 Configuration of CTD underwater stations

    アーマードケーブル Armored cable

    多筒採水装置 Multibarrel water sampler

    ニスキン採水器 Niskin water sampler 

    保護フレーム Protective frame

    採水器架台 Water sampler mounts

    CTDセンサ CTD sensor