What does DU mean in Ocean Science?
This page is about the meanings of the acronym/abbreviation/shorthand DU in the Academic & Science field in general and in the Ocean Science terminology in particular.
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What does DU mean?
- Dobson unit
- The Dobson unit is a unit of measurement of the columnar density of a trace gas in the Earth's atmosphere. It originated, and continues to be widely used, as a measure of total-column ozone, which is dominated by ozone in the stratospheric ozone layer. One Dobson unit refers to a layer of gas that would be 10 µm thick under standard temperature and pressure, sometimes referred to as a 'milli-atmo-centimeter.' For example, 300 DU of ozone brought down to the surface of the Earth at 0 °C would occupy a layer only 3 mm thick. One DU is 2.69×10^16 ozone molecules per square centimetre, or 2.69×10^20 per square metre. This is 0.4462 millimoles of ozone per square metre. A baseline value of 220 DU is chosen as the starting point for an ozone hole since total ozone values of less than 220 Dobson Units were not found in the historic observations over Antarctica prior to 1979. Also, from direct measurements over Antarctica, a column ozone level of less than 220 Dobson Units is a result of the ozone loss from chlorine and bromine compounds. In addition, Dobson Units are often used to describe total column densities of Sulfur Dioxide, which occurs in the atmosphere in small amounts due to the combustion of fossil fules, from biological processes releasing dimethyl sulfide, or by natural combustion such as forest fires. Large amounts of sulfur dioxide may be released into the atmosphere as well by volcanic eruptions. The Dobson Unit is used to describe total column amounts of sulfur dioxide due to the fact that it appeared in the early days of ozone remote sensing on ultraviolet satellite instruments.