The Center for Atmospheric Sciences | » Ryan M. McCabe

    • B.S., Physics, Gettysburg College, 2015

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  • Ryan M. McCabe

    I am currently a fifth-year Planetary Science Ph.D. candidate at Hampton University. I earned my B.S. in Physics from Gettysburg College in 2015 with minors is mathematics and music.

    My current research interests focus on atmospheric dynamics and cloud features primarily on Venus using cloud-tracking techniques and ground-based observations. The purpose of this work is to find how the Y-feature (a UV dark global-scale at ~65-70km altitude) might be connected to atmospheric superrotation on Venus (atmosphere rotates ~60 times faster than surface; much faster when compared to Earth at nearly unity rotation). In planetary atmospheres, wind speeds can be measured by analyzing the motions of clouds. The clouds act as tracers of the wind movements and thus by measuring their movements one can interpret what the wind field is. A useful diagnosis of a planet’s global atmospheric dynamics is the zonal (east-west) mean wind profile, i.e., mean of the zonal component of the wind vectors. I currently employ a two-dimensional Correlation Imaging Velocimetry (CIV) technique developed at Hampton University. The two-dimensional method calculates the correlation between two-dimensional subwindows within the two images; the subwindows are shifted in the north-south directions as well as in the east-west (creating a search window). I utilize this automatic 2D technique for my research projects. I additionally utilize an automatic image pair matching algorithm to find image pairs to feed the CIV algorithm, netting us over 35,000 image pairs across the entire mission of Venus Express. The result is about 25 million wind vectors allowing us to characterize the wind field of Venus from 2006-2013. I then use this background profile to better isolate features seen in UV for wave analysis. Through wind and wave analysis, we hope to directly measure the momentum transportation associated with the Y-feature and associated waves to understand the extent to which the Y-feature maintains superrotation.

    In addition to image analysis as discussed above, I also have worked with the 3.5m telescope at Apache Point Observatory as well as small 10-inch telescopes with lucky imaging to gain further insight into Venusian global-scale cloud-top features seen in UV. This has been in cooperation with the JAXA Akatsuki spacecraft covering both simultaneous observations and complementary to gaps in observational coverage due to spacecraft precession.

    Recent work has also started including work on assembling a GRAM (General Reference Atmosphere Model) for Venus to be provided for future spacecraft missions’ EDL (Entry/Descent/Landing) teams.

    Beyond Venus, I have also worked on Uranus temperature/pressure profiles also for EDL in a mission concept study.

    While at Gettysburg for my undergraduate career, I completed a Senior Capstone project entitled “Simulated Stratospheric Aerosol (H2SO4) Size Distribution Effects on Total Phase Function and Top of Atmosphere Flux.” This was a follow-up/completion of a summer internship at Hampton University which involved investigating how the top of atmosphere radiative budget was dependent on stratospheric aerosols’ size, standard deviation of that size, and concentration.

    Project: Analysis of Venusian Zonal Winds Using Venus Express Data

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    We measure the zonal mean wind structure of Venus between 2006 and 2013 in the ultraviolet images captured by the Venus Monitoring Camera (VMC) onboard the ESA Venus Express (VEx) spacecraft which observed Venus’s southern hemisphere. Our wind measurements employ a digital two-dimensional Correlation Imaging Velocimetry (CIV) method to track cloud motions. Our current focus is on understanding […]