Method for Correcting and Reducing the Pressure Data Recorded at the PAM II Stations during GALE.

摘要

The data recorded at the PAM II stations during GALE will enable researchers to gain a better understanding of the mesoscale processes involved in the various phenomena, however, the recorded pressure cannot be directly analyzed because it has not been corrected or reduced to sea level. This paper presents a method for correcting and reducing the pressure data. The Barnes objective analysis scheme was employed to determine the pressure correction for each PAM II station. The corrected pressures are reduced to sea level using the standard NWS reduction procedure outlined in the Manual of Barometry (1963), which was rather involved and included a number of assumptions to obtain the sea-level pressures. An empirical formula was derived for the GALE dataset to calculate the sea-level pressures for the PAM II stations. Pressure analyses involving the corrected and reduced PAM II pressures for two cases were in good agreement with the NMC analyses for the same times. Another method for representing the surface geostrophic wind field and the horizontal pressure field, is explored to determine the true ageostrophic wind components in a cold-air damming situation and to produce a horizontal pressure field that would eliminate the arbitrariness of the standard pressure reduction procedure. The result is an improvement over the geostrophic wind, but the observed winds are still highly ageostrophic in this cold-air damming situation. Theses. (jhd)