decibar

The decibar (dbar) is a unit of pressure used primarily in oceanography and meteorology. It is defined as one-tenth of a bar, which is equivalent to 100,000 pascals (Pa) or 1,000 hectopascals (hPa). The term "decibar" is derived from the Greek prefix "deka," meaning ten, and "bar," which refers to the unit of pressure.

The decibar is commonly used to measure pressure in the ocean, where it is more practical than the bar due to the smaller scale of pressure changes. For example, the average pressure at the surface of the ocean is approximately 1013.25 dbar, which is equivalent to 1 atmosphere (atm) or 1013.25 hPa. As depth increases, the pressure also increases, with an additional 1 dbar for every 10 meters of depth.

In meteorology, the decibar is sometimes used to express atmospheric pressure, although the hectopascal (hPa) is more commonly used. The conversion between decibars and hectopascals is straightforward, with 1 dbar being equal to 10 hPa.

The decibar is not an SI unit, but it is recognized for use with the SI. It is part of the set of non-SI units accepted for continued use with the SI, as defined by the International System of Units (SI). Despite its non-SI status, the decibar remains a useful unit in specific scientific disciplines.