LPI Welcomes New Postdoctoral Fellow Hart Gillespie
November 17, 2021
This photo was taken during totality in the total solar eclipse of 2017 at Carter and Holmes Orchids near Newberry, SC.
Recently, LPI welcomed a new postdoctoral fellow, Dr. Hart Gillespie. Dr. Gillespie will join Dr. Germán Martínez (LPI) on the Mars Environmental Dynamics Analyzer (MEDA) science team of NASA’s Mars 2020 mission, and will lead analyses of atmospheric measurements made by the Thermal Infrared Sensor (TIRS), one of the six environmental sensors comprising MEDA. Additionally, he will analyze measurements of Mars Climate Sounder (MCS) and modeling results from the Ensemble Mars Atmosphere Reanalysis System (EMARS) in conjunction with TIRS in attempts to link the lower boundary layer measured by TIRS and other MEDA instruments to the remainder of the martian boundary layer and the martian atmosphere.
LPI: How did you become interested in planetary science?
HG: I’ve been interested in meteorology and astronomy for as long as I can remember, and the solar system is a key part of astronomy. Some of my earliest memories include seeing Saturn’s rings for the first time in my backyard, reading any science book I could get my hands on, and watching the Weather Channel for hours on end. It is no surprise to me or anyone who has known me since childhood that I study what I do. As I proceeded toward college, I was drawn more toward math and physics than meteorology. My undergraduate degrees from Randolph College are in those fields.
LPI: When did you know that you wanted to pursue this as a career?
HG: I’ve always wanted to be a scientist, but the specific field was never clear. As I progressed through my undergraduate studies, I gained a little clarity in realizing that I’d like to be a physicist of some kind. My interest in planetary science, and more specifically the martian atmosphere, was realized in graduate school.
LPI: Did you have a mentor or another person in your life who was influential to your decision or career?
HG: I study the martian atmosphere because of Steven Greybush of Penn State. I applied primarily to experimental astrophysics programs to study gravitational waves. However, I also applied to the meteorology program at Penn State because of its reputation in meteorology and because I had noticed Steve’s work on the martian atmosphere. He and I chatted and met at Penn State’s graduate school open house. After considering my graduate school options, it was clear that Steve would be the best advisor for me.
LPI: What is the focus of your research?
HG: I study the martian atmosphere using the Ensemble Mars Atmosphere Reanalysis System (EMARS). The advantage of using a reanalysis is that it combines known information about the state of the martian atmosphere through observations with the full spatial and temporal coverage of computer models using a technique called data assimilation. This allows us to learn about the martian atmosphere in ways that we couldn’t by using a single dataset. I have studied midlatitude traveling weather systems, global dust storms, and water transport in the north polar region. At LPI, I’ll be investigating numerous ways to use EMARS in conjunction with observations from the Perseverance rover, notably temperatures at 40 meters above the surface of Mars measured by the Thermal InfraRed Sensor (TIRS).
LPI: What is the most unexpected or exciting result that you’ve encountered in your research?
HG: One might expect global dust storms on Mars to form primarily around the northern winter solstice due to the difference in light and temperature between the hemispheres being greatest at this time. One would think that such conditions produce the most wind, which would provide the best opportunity for storm formation. Mars models that lift dust when surface stress exceeds a threshold tend to initiate global dust storms around the northern winter solstice as well. However, since 1997, when twice-daily global observations became available at Mars, there have been three global dust storms, and two of them formed just after the start of the northern fall. As a result, we have more knowledge about global dust storms that form near the start of northern fall than those that form near the northern winter solstice.
LPI: What do you most look forward to as it relates to planetary science over the next 10 years?
HG: Due to the success of the Kepler mission, over the last 10 years we have learned about many planetary systems beyond our own. Given the rapid progress in exoplanet studies over the previous 10 years, the next 10 years will likely be quite exciting.
It will also be interesting to have a larger sample size of well-observed global dust storms on Mars to study. There are likely to be two more of those in the next 10 years, and once we have observed enough global dust storms, we may be able to learn how global dust storms form and grow in general.
Hart at the Glacier des Bossons on Mont Blanc during a research trip.
LPI: What would be your dream research trip?
HG: I think I’ve already taken that trip. The last Mars data assimilation meeting was held in the French Alps. In addition to talking with the foremost experts in my field about cutting-edge research into the martian atmosphere, I was able to spend a little time hiking and plenty of time enjoying the scenery.
I would prefer not to go to Mars. I like trees, water, and oxygen too much to leave Earth, even if only for the quick two-year round trip to Mars.
LPI: Do you have a favorite hobby or interest outside of work?
HG: I enjoy playing tennis. I have played for more than two decades and played on Randolph College’s team for two years. It’s a fun way to stay active.
I hiked most weekends while I was at Penn State. While Houston is not a place you’d imagine would be good for hiking, there are plenty of paths around, and the Lone Star Hiking Trail is not too far away.