A CGS unit of pressure equal to 10-9 bar or 0.1 millipascal (mPa). The nanobar is frequently used in meteorology to express the partial pressure of atmospheric ozone
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}