A study of the deviations of wind speeds and directions from geostrophic values

摘要: From a knowledge of the three-dimensional wind field as function space and time, total acceleration trajectory curvature can be computed, permitting evaluation geostrophic vector without recourse to analysed isobars or height contours. A study 618 cases at 10,000 ft for 3-day November sequence, using observed winds over North American continent, revealed that mean absolute angle between reported directions was approximately 15°. Large deviation angles were associated with low speeds, thus indirectly latitudes. The corresponding cross-isobar component slightly greater than 5 mi hr−1. speeds order 7 hr−1, relative being just under 30 per cent. deviations chiefly hence latitudes. The exceeded 40 hr−1 day−1. corresponded radius 175 mi. It found components these terms associated, formally, horizontal vertical advection virtually identical in magnitude, illustrating importance velocity contribution accelerations curvatures. local tendency numerically smaller two advective care accelerations, but larger case