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The Origins of Air Parcels Uplifted in a Two Dimensional Gravity Wave in the Tropical Upper Troposphere During the NASA Stratosphere Troposphere Exchange Project (STEP)During January and February 1987, as part of the Stratosphere-Troposphere Exchange Project, the NASA ER-2 made 11 flights from Darwin, Australia to investigate dehydration mechanisms in the vicinity of the tropical tropopause. After the monsoon onset in the second week of January, steady easterly flow of 15-25 ms (exp -1) was established in the upper troposphere and lower stratosphere over northern Australia and adjacent seas. Penetrating into this regime were elements of the monsoon convection such as overshooting convective turrets and extensive anvils including cyclone cloud shields. In cases of the latter, the resulting flow obstructions tended to produce mesoscale gravity waves. In several instances the ER- 2 meteorological and trace constituent measurements provide a detailed description of the structure of these gravity waves. Among these was STEP Flight 6, 22-23 January. It is of particular interest to STEP because of the close proximity of ice-laden and dehydrated air on the same isentropic surfaces. Convective events inject large amounts of ice into the upper troposphere and lower stratosphere which may not be completely removed by local precipitation processes. In the present instance, a gravity wave for removed from the source region appears to induce relativity rapid upward motion in the ice-laden air and subsequent dessication. Potential mechanisms for such a localized removal process are under investigation.
Document ID
Document Type
Reprint (Version printed in journal)
Selkirk, Henry B. (NASA Ames Research Center Moffett Field, CA United States)
Pfister, Leonhard (NASA Ames Research Center Moffett Field, CA United States)
Chan, K. Roland (NASA Ames Research Center Moffett Field, CA United States)
Kritz, Mark (State Univ. of New York Albany, NY United States)
Kelly, Ken (National Oceanic and Atmospheric Administration Boulder, CO United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1989
Subject Category
Meeting Information
Hurricane and Tropical Meteorology(San Diego, CA)
Distribution Limits
Work of the US Gov. Public Use Permitted.