James H. Ruppert, Jr., M.S.
Email: ruppert"at"atmos.colostate.edu
Department of Atmospheric Science, ATS 314
Colorado State University
Fort Collins, CO
80523-1371


Department of
Atmospheric Science
CV       Research Group       Swell Watch       SPC       NWS       Cheyenne, WY Radar
Diego Garcia during DYNAMO (Oct 2011).

Welcome!

I am a currently a Ph.D. candidate in the Mesoscale and Cloud Dynamics group at Colorado State University, led by Prof. Richard H. Johnson. I completed my M.S. (2012) in the same group, and my B.S. (2009) at the University at Albany where I carried out an undergraduate thesis under the advisement of Prof. Lance F. Bosart.

My Ph.D. research focuses on tropospheric moistening by shallow and congestus clouds and their modulation by the diurnal cycle during the suppressed and building phase of the Madden-Julian oscillation. My other research interests include mesoscale gravity waves and their interaction with thunderstorms, and diurnal thunderstorm activity in Taiwan's summer monsoon (see below). My primary research tools include field study observations (e.g., soundings and radar) and cloud models.

Surface pressure analysis from Ruppert and Bosart (2014, MWR) for 0900 UTC 7 March 2008, generated using time-to-space conversion of five-minute surface observations, with base reflectivity to indicate rainfall. The sharp pressure gradient straddling the back edge of the rainfall in central MS represents a northeastward-propagating mesoscale gravity wave (MGW), which caused a rapid pressure drop of ~11 hPa, wind gusts over 20 m/s, and a sudden end to the rainfall as it passed.
Schematic depiction from Ruppert et al. (2013, MWR) of the diurnal cycle of flows and rainfall during a disturbed and undisturbed period of the Mei-yu (rainy) season in Taiwan. The undisturbed period is characterized by southwesterly flow, and the disturbed period is characterized by a "Mei-yu front" that separates southwesterly flow to the south from northeasterly flow to the north and enhances lifting around Taiwan. During morning hours in both periods, the flow is deflected around Taiwan and rainfall is focused offshore. A morning lee vortex appears southwest of Taiwan in the stable northeasterly flow during the disturbed period. During afternoon hours, the flow traverses the high terrain, and thunderstorms form over Taiwan's windward slopes. Stronger impinging flow during the disturbed period leads to more vigorous thunderstorms, greater production of lofted ice, and a shift of the heaviest rainfall into the high terrain. This rainfall shift increases the threat of landslides in Taiwan's loose soil.
The top of Rose Garden Hill on day 3 of 4 of the
Kokopelli Trail (photo credit: David Duncan).
Updated June 2014