The square degree unit is mostly used in astronomy and optic (its usage is strongly discouraged in all other domains, including in cartography). The whole sphere covers a solid angle (seen from its centre) of (129600/π) deg² (approx. 41252.961 deg²) and is the solid angle covered by a conic section of a sphere, whose opening apex is exactly 360° (note that the measure of a solid angle in square degrees is not proportional (and does not vary polynomially with) the measure of the associated planar angle in degrees of opening of its associated cone. In cartography, you can't simply multiply a difference of longitudes and a difference of latitudes, both expressed in degrees to get an exact measure of a solid angle in square degrees (this will just be an approximation only if these differences are very small, below one minute of arc each, and the covered area is very near the equator, i.e. at very low latitudes where the small area will be nearly rectangular instead of being nearly trapezoidal in median latitudes, or nearly a disc sector near the poles).
1 atm = 1013.25 mbar = 1013.25 hPa] = 1.01325×105Pa (commonly used in atmospheric meteorology, in oceanology and for pressures within liquids, or in the industry for pressures within containers of liquified gas)
References
Taylor, Barry N. (ed.) (2001). The International System of Units (SI) (2001 ed., Special Publication 330). Gaithersburg, Maryland: National Institute of Standards and Technology. pp. 15–19. Viewed at http://physics.nist.gov/Pubs/SP330/sp330.pdf
