The square root of one value of this quantity divided by the beta-plane parameter gives the Rhines scale. In some non-dimensionalization problems, it's good to know that the units of geopotential are the (15[1])square of this quantity's units. The ratio of the pressure gradient to the density equals the Coriolis parameter times a component of this (15[1])quantity (-5[1])for a (15[1])system in geostrophic balance. Derivatives of a function denoted psi give this (15[1])quantity's (*) zonal (-5[1])and meridional components. As depth increases, this quantity's direction twists away from the direction of (10[1])a shearing wind, forming an Ekman spiral. (10[2])This (10[1])quantity multiplies cross-sectional (10[2])area to (10[2])give (10[1])volumetric flow rate, (10[1]-5[1])and its (10[1])curl (10[1])is the vorticity. (10[3]-5[1])For 10 points, name this quantity, which for large currents like the Gulf (10[1])Stream can reach values of 2.5 meters per second. ■END■ (10[2])