CTD - Conductivity-Temperature-Depth Meter

Japanese: CTD - シーティーディー（英語表記）conductivity-temperature-depth meter

An instrument that simultaneously measures electrical conductivity, water temperature, and pressure inside the ocean. The sensor is lowered into the water from the ship, and the signal is input to the ship's computer via a cable. Electrical conductivity is a function of water temperature, salinity, and pressure, and salinity can be estimated by knowing the pressure and water temperature at each depth. It has become the main method of observing water temperature and salinity in recent years because it can measure continuously in the depth direction and has good measurement accuracy. Dissolved oxygen sensors are often also attached, but their accuracy is lower than that of the former. For the purpose of calibrating the measurement values, a water sampler (rosette sampler) is attached and connected to it, and water is sampled at any depth. Some models can be used down to a depth of 10,000 m. Some models have a built-in data recorder that is lowered into the water along with the sensor.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

海洋内部の電気伝導度・水温・圧力を同時に測定する機器。船上からセンサを水中に下ろし，信号はケーブルを通して船上のコンピュータに入力される。電気伝導度は水温・塩分・圧力の関数で，各深度の圧力と水温を知って塩分を推算する。深さ方向に連続的に測定できること，測定精度が良いことから，最近の水温・塩分観測の主力となっている。溶存酸素量のセンサも取り付けられることが多くなったが，前者に比べて精度は悪い。測定値の検定の目的で，採水器 (ロゼットサンプラー) を連結して取り付け，任意の深さで採水する。1万mの深海まで使えるものもある。センサと一緒にデータ収録器も水中に下ろす内蔵式のものもある。

出典　ブリタニカ国際大百科事典小項目事典ブリタニカ国際大百科事典小項目事典について　情報

<<: Designated infectious disease - teidensenbyo

>>: Citizen's band