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A comparison of modern and historical methods for calculating Montgomery steamfunction


Correspondence to: P. S. Market, Department of Soil, Environmental, and Atmospheric Science, 302 Anheuser Busch Natural Resources Building, University of Missouri, Columbia, MO 65211, USA.

E-mail: marketp@missouri.edu


The suggestion has been made that the Montgomery streamfunction is now calculable for isentropic analysis purposes simply by applying the equation Ψ = gZ + cpT. Historically, this practice has been frowned upon, as measurements aloft did not have the accuracy requisite to allow such practice. Instead, an integral approach to calculating Ψ has been preferred to get workable values. Yet, advancements in the accuracy of radiosonde measurements have occurred, especially with global positioning system (GPS)-verified height data. Herein, we show that the values from the simple and integral methods of getting Ψ are very similar, and differ by only ∼0.2%. © 2012 Royal Meteorological Society