Buys Ballot’s law is a synoptic meteorology rule stating that if, in the northern hemisphere, an observer stands with his back to the wind, pressure is lower on his left hand than on his right, while in the southern hemisphere the converse is true. This was enunciated by Buys Ballot of Utrecht in 1857 and is basically a restatement of the fact that winds blow clockwise around a depression in the northern hemisphere and anticlockwise in the southern hemisphere. This law is an atmospheric corollary of the principle of the Coriolis force.
- M. Buys-Ballot. 1857. Note sur le rapport de l'intensité et de la direction du vent avec les écarts simultanés du baromètre, Académie des sciences (France). Comptes rendus hebdomadaires, TOME XLV
- Physical Oceanography Index