geostrophic wind The wind blowing above the boundary layer that, by its strength and direction, represents the balance between the pressure-gradient force, acting directly from the region of higher pressure towards the region of lower pressure, and the Coriolis effect (force), deflecting moving air to the right (in the northern hemisphere and to the left in the southern hemisphere). When these are in balance the wind flows parallel to the isobars (see Buys Ballot's law). Air is also subject to a centrifugal force, owing to the curvature of the air's path around a centre of low or high pressure. In the boundary layer, air experiences friction with the surface, causing it to flow across the isobars, at an angle of 10–20° over the sea and 25–35° over land (where friction is greater). See also gradient wind.

geostrophic wind The wind blowing above the boundary layer that, by its strength and direction, represents the balance between the pressure-gradient force, acting directly from the region of higher pressure towards the region of lower pressure, and the Coriolis force (effect), deflecting moving air to the right (in the northern hemisphere and to the left in the southern hemisphere). When these are in balance the wind flows parallel to the isobars (see BUYS BALLOT'S LAW). Air is also subject to a centrifugal force, owing to the curvature of the air's path around a centre of low or high pressure. In boundary layer, air experiences friction with the surface, causing it to flow across the isobars, at an angle of 10–20° over the sea and 25–35° over land (where friction is greater). See also GRADIENT WIND.