Aircraft Measurement of Mesoscale Pressure Gradients and Ageostrophic Winds

Abstract

Determination of the horizontal pressure gradient force over distance scales less than 100 km is possible using airborne altimetry and detailed maps of the underlying terrain. To detect the very small isobaric slopes, instrumentation must perform up to specification and aircraft position must be known within about 250 m in order to achieve an adequate matching of altimeter height and terrain height. Numerous test flights were conducted to study the stability of the technique. Results indicate the system is capable of resolving pressure gradients with equivalent geostrophic wind errors of approximately ± 1 m s?1 over a 100 km horizontal scale.