Alumni Profile - John Yorks

MU alum Dr. John Yorks, science lead on CATS

Dr. John Yorks

What degrees do you currently hold?
I have three degrees in total: a Bachelor of Science in Meteorology from Millersville (2006), a Master of Science in Meteorology from Penn State University (2007), and a PhD in Atmospheric and Oceanic Science from University of Maryland (2014).

Tell us about getting a job with NASA – how and when did that come about?
As a graduate student at Penn State, I worked on several NASA funded projects because my advisor worked at NASA for 20 years. Through this work, I met many NASA scientists during field studies and conferences. One such colleague alerted me to a job opening for a NASA cloud and aerosol remote sensing scientist in 2007. This was slightly different than the work I was doing at graduate school (I was studying ozone pollution), but NASA is one of the best places to work in earth science, so I embraced a new challenge.

What is your daily life like at NASA?
My mornings typically consist of checking the data from our instrument on the International Space Station (ISS) for interesting events (wildfires, dust storms, volcanic eruptions, etc.) and/or any issues. I also answer emails about data availability and catch up with our team on our current projects. After that, I spend time writing software programs that use algorithms to process the data and create products for the science community. Some days I also analyze the data and write papers to publish the results. When I need a break from my computer, I spend time in our lab where I help build and test new instrumentation to study clouds and aerosols.

Do you work with any other MU alums?
There are two other MU alums in our research group that have been key to our success. Patrick Selmer (2010) is former Meteorology student who has written key algorithms that process the raw data from our instrument on the ISS. Rebecca Pauly (2013) is working on an aircraft instrument that will participate in a multi-year carbon dioxide study.

What is your favorite part of your day? Least favorite?
I love my job and I think it is hard to identify one aspect of my job that is my favorite. It is a lot of fun to help build an instrument, write the algorithms that process the data, and then publish the results. The most rewarding part is contributing to the advancement of our knowledge of the earth system.

Tell us about the research you’re working on.
My research involves the study of clouds and aerosols using a laser remote sensing instrument called lidar. Lidar instruments are really quite simple. The instrument shines laser light at the Earth’s atmosphere and measures the amount of light scattered back to the instrument from particles such as ice crystals and aerosols. By timing the difference between emission and detection of the laser light, the precise altitude of the particles can be determined. My group has several lidar instruments that fly on aircraft as high as 65,000 ft. and an instrument called Cloud-Aerosol Transport System (CATS) on the ISS.

What is cloud and aerosol remote sensing and why is it important?
Cloud and aerosol remote sensing is a method of measuring cloud and aerosol properties, using satellite or high-flying aircraft, without coming into physical contact with the clouds and aerosols. Creating satellite missions for remote sensing of the earth and our solar system is a primary function of NASA.

Small particles such as dust blown from a desert or a volcanic plume are known as aerosols. In addition to being harmful to human health, aerosols directly impact climate by absorbing and reflecting sunlight. They also indirectly influence climate by interacting with clouds.

Clouds are one of the largest uncertainties in predicting climate change because clouds are the key regulator of the planet’s average tem­perature. Thick water clouds near the Earth’s surface can cool the climate by reflecting sunlight back to space, while high ice clouds can warm the climate by trapping the Earth’s radiation.

Small changes in the abundance or location of clouds and aerosol could even change the climate more than the changes scientists anticipate from greenhouse gases. Climate computer models use our data to improve forecasts for these factors, which help reduce uncertainties in climate prediction.

What sparked your interest in this area (cloud and aerosol remote sensing)?
As a student at Millersville, I participated in an undergraduate research project lead by Dr. Richard Clark. The project involved collecting and analyzing pollution measurements in Lancaster County. This opportunity really sparked my interest in atmospheric science research, as I enjoyed determining the complex interactions between weather patterns, clouds, and pollution (which includes aerosols).

What is Cloud-Aerosol Transport System (CATS) and what was your role in creating it?
CATS ( is a 3-wavelength lidar instrument that has been operating on the ISS since February of 2015. While monitoring global hazards from above, CATS determines the height, thickness and the extent of smoke, dust particles, and volcanic ash in our atmosphere. The cloud and aerosol data provided by CATS helps us better understand Earth’s complex atmospheric processes.

My role as Science Lead of the CATS instrument involves developing the science goals of the project, leading the great team of scientists that create the algorithms and data products to meet these goals, and ensuring that the instrument is designed and built to achieve these goals. I am also responsible for communication with the science community and publication of CATS science results.

How did Millersville University help shape you personally and professionally?
So much of who I have become personally and professionally is due to my time at Millersville. As a junior, I met my wife Haley McLaughlin (’07) in Brookwood. We have been together for 12 years and now have a 2-year old son, John Richard (J.R.). As captain of the ice hockey team, I really learned how to be a leader and made some great friends that I still keep in touch with today. Professionally, the MU meteorology department laid the foundation of knowledge and research skills that helped me land a job at NASA.

How has MU’s meteorology department assisted in accomplishing your professional goals?
I owe much of my success to the Meteorology program at Millersville. The challenging coursework, undergraduate research opportunities and career guidance the faculty provided shaped me as a researcher and set me on a path to succeed. As a student I participated in two undergraduate research projects lead by Dr. Clark and Dr. Sepi Yalda. Participating in these projects, which can be hard to come by in many other undergraduate meteorology programs, gave me the desire to become a researcher and go to graduate school. All the MU meteorology professors are extremely knowledgeable in the field and were more than willing to spend extra time with me to help understand a concept and decide on the correct career path, especially Dr. Yalda.

What organizations where you a part of during your time at Millersville University?
During my time at Millersville I was captain and president of the ice hockey team, a lead forecaster for the Campus Weather Service, a member of the Millersville chapter of the American Meteorological Society (AMS), lead researcher for the NSF-funded project called Linked Environments for Atmospheric Discovery (LEAD).

Are there any professors or alumni from MU that you still keep in contact with or have inspired you?
I still keep in contact with all four MU meteorology professors: Dr. Todd Sikora, Dr. Alex Decaria, Dr. Clark, and Dr. Yalda. I often see the professors and friends from the meteorology department at conferences and meetings within the field. I also keep in contact with many of the friends I made over the years on the ice hockey team and in the dorms, even getting together with some of them several times a year.

What is your favorite memory while at Millersville?
One of my favorite memories from Millersville was Homecoming 2005. At the football game, I escorted my girlfriend at the time (Haley McLaughlin) as she was crowned Charity Queen after raising over $16,000 for the Make-A-Wish Foundation. The night before, I scored 3 goals as Millersville ice hockey beat archrival Franklin and Marshall 8-3. Another great memory was attending the 2005 AMS conference in San Diego, CA with my meteorology classmates.

Do you have any advice for current Millersville University students?
My advice for current Millersville students is that they should take advantage of as many new opportunities as possible, whether it is joining a club, taking an internship, or working on a department project. Millersville offers many of these things and it may lead you down a career path you never imagined and absolutely love. You may also meet friends that you will have forever. You won’t know until you try.

3-2-1 Ignition

Read more about the work of MU alums, Dr. John Yorks and Patrick Selmer, with NASA's Cloud-Aerosol Transport System (CATS).