an instrument for recording the temperature at various depths in the ocean
A scientific instrument used to measure underwater temperatures.
A device for obtaining a record of temperature against depth (strictly speaking pressure) in the upper 300 meters of the ocean from a ship underway. Some of these devices are expendable and designated as XBT.
A device used to obtain a record of temperature against depth ( pressure) in the ocean. May be referred to as a B.T.
(Abbreviated BT.) A device for obtaining, from a ship under way, a record of temperature against depth (strictly speaking, pressure) in the upper 300 m of the ocean. For a thermal element it has a xylene-filled copper coil, which actuates a stylus through a Bourdon tube. The pressure element is a copper aneroid capsule that moves a smoked glass slide at right angles to the motion of the stylus. A double analog record is thus obtained as the BT is lowered and recovered. This device has generally been replaced by the expendable bathythermograph (XBT).
The bathythermograph, or BT, is a small torpedo-shaped device that holds a temperature sensor and an element to detect changes in water pressure. Lowered into the sea from an under way ship, the BT records pressure and temperature changes as it is dropped through the water. Because the pressure in decibars is approximately equal to the depth in meters, depth can be correlated with temperature.