A METHOD OF ANALYSIS OF SURFACE 6E0STR0PHIC WINDS IN MOUNTAINOUS REGIONS

摘要

Fictitious pressure gradients appear on sea-level charts in mountainous regions as a result of the reduction of the barometer to sea level and because of the ability of mountain barriers to sustain large pressure differences between stations on opposite sides. These fictitious pressure gradients limit the useful¬ness of the sea-level isobars in depicting the surface air flow. Moreover, local effects often make the actual surface winds nonrepresentative. It is, therefore, desirable to devise some method of representing the air flow over mountainous terrain that will serve the same function as isobaric analysis in flat regions.nIn the present study constant pressure charts were analyzed at 50-mb inter¬vals between 950 mb and 750 mb, the height contours being terminated where they intersected solid ground. At these intersections of the pressure surfaces with the earth's surface, geostrophic winds were measured, plotted on a base map, and analyzed by means of streamlines and isotachs.