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Meet Hans Moosmüller, Ph.D.

  • Published in Featured Researchers

Hans Moosmüller, Ph.D., is a research professor in the Division of Atmospheric Sciences (DAS) at the Desert Research Institute (DRI) in Reno, NV, and the senior director of DRI’s Wildland Fire Science Center. He specializes in the study of aerosols, which are tiny particles of solids or liquids that become suspended in the atmosphere and canimpact air quality, climate, and visibility (i.e., dust, wildfire smoke, smog). Hans holds a Ph.D. in physics from Colorado State University and a M.S. in physics from Ludwigs-Maximilians Universität in München, Germany. He has been a member of the DRI community since 1991 and has worked on both the Las Vegas and Reno campuses. Hans was awarded the Nazir and Mary Ansari Medal for Excellence in Science in 2012 and the Nevada Regents’ Researcher Award in 2013. In his free time, he enjoys bicycling, rock climbing, skiing, and other outdoor activities. 

DRI: What do you do here at DRI?

HM: Well, it has changed over the years. I started here 27 years ago. I was originally hired to work at the Environmental Protection Agency’s research lab in Las Vegas, where we had a big cooperative agreement. There, we built an instrument to remotely measure ozone concentrations in the troposphere, where ozone is a pollutant, unlike the ozone layer in the stratosphere that protects us from UV. That was very successful. After that contract went away, I moved to beautiful Reno and started writing proposals.

Right now, a lot of my work involves aerosols. Many people think of aerosols as the stuff that comes out of spray cans. What scientists think of as aerosols are small particles suspended in the atmosphere, including the particles in wind-borne mineral dust and combustion emissions. I have developed some instrumentation here at DRI, often with support from the Major Research Instrumentation (MRI) program of the National Science Foundation (NSF). We use this instrumentation to make unique measurements related to aerosol optics, which is the interaction of light with aerosols. We have patented and licensed some of these instruments.

I am also the director of DRI’s Wildland Fire Research Center, so I sometimes wear an administrative hat. There’s a lot of fire related research going on at DRI. In our Division of Atmospheric Sciences (DAS), we look at fire emissions and their fate in the atmosphere; in the Division of Earth and Ecosystem Sciences (DEES), scientists are interested in fire ecology and what it does to the natural environment, plants, animals and all that. In the Division of Hydrologic Sciences (DHS), there’s fire hydrology, how fire affects the soil, the water uptake of the soil, and the water quantity and quality in the runoff. So, what we’re trying to do is bring scientists fromthese three divisions together in doing interdisciplinary and multidisciplinary work in fire sciences. In addition, we’re looking to using drones as a transformative tool for fire science and management, because acquiring fire data with airborne platforms has proven to be very dangerous and difficult.

Moosmuller enjoys research and skiing on snowHans Moosmuller enjoys spending time in the snow, both for work and for fun.

DRI: You mentioned that a lot of your work is focused on aerosols. Why are aerosols important to measure and understand?

HM: Aerosols are important for several reasons. One reason is climate change. They reflect and absorb part of the light and the energy that comes from the sun, and redistribute it. So, they can cause both cooling and warming. They can counteract global warming or enhance it.

They’re also important for visibility, which we need obviously around airports and when driving a car. If you’ve ever driven into a dust or wildland fire plume and you suddenly can’t see, you realize how mass collisionscan be caused by visibility impairment. Visibility is protected in many U.S. National Parks and wilderness areas to improve enjoyment of scenic vistas. It isalso very important for our friends in the military, especially those who are deployedon the Arabian Peninsula and in the Middle East and use rangefinders, target designators and other optical devices. In addition, visibility is the public’s closest connection to air quality; if you can’t see Mt. Rose from DRI, it’s getting pretty bad.

DRI: What are some of the questions related to aerosols that you are investigating right now?

Moosmuller working from a tower.Sometimes Hans' work takes him high into the air. Here, he is installing instruments on a tower at Fort Bliss Army Base near El Paso, TX during a study of dust entrainment and transport from military vehicles traveling on unpaved roads.

HM: I’m interested in aerosols in the atmosphere, their emissions, measurement, optical properties, and aging; there’s still a lot of work to be done. I work on theory and instrument development, ambient measurements, and laboratory experiments. Lately I’ve gotten interested in the fate of aerosols once they are deposited, especially on snow and on solar cells, for example.

Snow is quite white in the visible spectrum (snow white) and reflects most of the incoming solar radiation. However, if dark aerosols, such as black carbon, are deposited onto the snow even in minor (ppb) quantities, they greatly decrease the whiteness and increase absorption of solar radiation, leading to earlier snowmelt and runoff. All of these are effects that we need to understand to predict, for example, water availability from snowmelt.

Aerosol deposition on solar panels can affect the efficiency of these panels. It’s not so much a problem here in Reno, but on the Arabian Peninsula you get a lot of dust deposition and a single dust storm can reduce the efficiency of solar panels by a factor of two.That means you have to clean the solar panels, and understanding theseoptical losseshelps you forecast solar energy production and optimize cleaning schedules.

Currently, I am advising three graduate students here at DRI. One has just finished his degree – he’s been working on the solar panel problem, and has gotten a National Research Council post-doctoral fellowship to work in Washington, D.C. at the Army Research Laboratory. Another studentis working on questions related to aerosol deposition on snow. The third student is investigating optical properties of fresh and aged biomass burning emissions, and she is also involved in a project developing a new satellite concept.

DRI: You are originally from Germany. How did you end up here DRI?

HM: I did my master’s degree in physicsin Germany. I wasn’t quite ready to get a job yet, and I didn’t want to continue where I was, so I came to Colorado and did a Ph.D. and a post-doc and enjoyed the local mountains. Then I nearly moved back to Germany, but I travelled around for half a year. I travelled up to Alaska and back down to California/Nevada. On the way, I applied for two jobs. One was at the University of Alaska, and one was working for the EPA in Las Vegas, which greatly appealed to me because of the excellent rock climbing in nearby Red Rock Canyon. I got two job offers; I picked DRI because it offered the most opportunities for interdisciplinary research.

My final DRI job offer was mailed to me at Yosemite Valley, General Delivery. I was homeless and having a lot of fun rock climbing at that time. So, I worked for three years in Las Vegas, and then I moved up to Reno and I’ve been having fun here ever since.

What I especially like about DRI is that it’s very interdisciplinary – even just within one division, we have people from 10 or 20 different fields. If I was in an academic position at a university, everyone else would have a Ph.D. in physics and work would be more boring. Here, I constantly talk to people with different backgrounds, feel constantly ignorant, and hopefully, once in a while, I learn something. That’s my favorite part.

In his free time, Moosmuller enjoys biking.In his free time, Hans enjoys bicycling and many other outdoor activities.


You can learn more about Hans and his work on his research page:


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