Dr. Mike Larsen
Office: RHSC 310
Labs: RHSC 303b
(between RHSC 303 and 304)
Phone: (843) 953-2128
NSF biosketch: (PDF)
Basic CV: (PDF)
Full CV: (PDF)
Dr. Larsen's Spring 2014 Schedule: (PDF)
Faculty Resource Request Form:
- Current Courses (Spring 2014) -Physics of Sound and Music (PHYS 150)
Classical Mechanics (PHYS 301)
Research Seminar (PHYS 419)
- About Me -The academic basics can be found if you check out one of my CVs to the left. A more comprehensive biography (you must be bored) can be found here.
- Students Currently Working in the Larsen Atmospheric Physics Lab -Joerael Harris -- Studying rainfall DSD variability.
Timothy Hayward -- Exploring tests to determine if a given data-set is statistically stationary.
Cassidy Jenks -- Studying different methodologies of measuring rainfall one drop at a time.
Robert Lemasters -- Investigating the feasibility of using a 3d printer for rapid atmospheric instrumentation prototyping.
Katelyn O'Dell -- Studying meteorological aspects of rainfall spatial and temporal variability.
Alexis Payne -- Exploring the effect of the diurnal cycle on the time-dependent spectral signature of boundary layer turbulence.
Annie Steele -- Exploring on a way to build an affordable rain velocimeter.
Joshua Teves -- Working on computational models of numerical radiative transfer.
- Research Interests -I have quite a few varied research interests, most related loosely to the field of Atmospheric Microphysics. If there is an underlying theme, it would probably be "how discreteness matters in the atmosphere". In other words, rain comes down in drops -- when, how, and why does this matter? Some of the basic problems I'm working on are briefly summarized below.
1. Radiative Transfer through Correlated Random Media -- I study how light propagates through clouds and other systems when there is statistical structure more completed than "perfect spatial randomness". Some of the ideas we deal with here are subtle, but ultimately the idea is straightforward enough to understand. Let's say you have 100 trees in two 1 acre fields -- in one of the fields, the trees are placed perfectly randomly within the field. In the second field, the trees are put together in clumps. Which field can you see further through (on average)? According to Jensen's inequality, (or common sense), we can argue that though there are places in the second field where we can't see very far at all, there are other areas (without any trees) where we can see all the way through. On average, you see further through the "clumpy forest". We explore this phenomena in detail, studying how much futher you see through "clumpy" systems than "perfectly random" systems, and try to relate it to the nature of the clumpiness. This work is mostly computational in nature, and we have some pretty awesome computer hardware to attack this problem. (Including using some GPU computing techniques).
2. Spatial and Temporal Variability in Rainfall -- I study how rainfall variables (e.g. accumulations and raindrop size distributions) vary in space and time. Everyday experience suggests that rainfall is very variable; who doesn't have experience waiting to run to your car after leaving a shop during a rainstorm because you think the rain might "let up a little" in the next few minutes. However, most of our tools used to measure rainfall (e.g. radar, weather station rain gauges, etc.) only give information about rain every few minutes and often do not contain any spatial information on scales less than a few city blocks in size. We know rainfall varies substantially on spatial and temporal scales shorter than this, but the nature of that variability is poorly understood. We're working on this and would like to ultimately use the information on small spatial scales to tell us something about the large scale structure and behavior of the storm.
3. Aerosol Mixing -- There is a long history of research into atmospheric turbulence and wind patterns in the boundary layer of the atmosphere. The behavior of pseudo-passive scalars (i.e. aerosols, or airborne particulates) and how they behave due to the forcings of the statistically structured turbulent wind patterns, however, is not nearly as well understood. Using some basic tools from stochastic geometry, we hope to find a way to describe the statistical structure of aerosols as they mix due to ambient wind flow patters.
4. Stochastic Geometry -- Several of the problems we study involve using some relatively obscure mathematical formulas that inter-relate simple statistical properties of geometric structures. (The field of stochastic geometry). There are a number of tools developed for use in these types of studies, but many need a little bit of "tweaking" before they are suitable for use in practical applications for analysis within a subfield. Although this is vague, we work on developing some of these "tweaks".
5. Wavelet Analysis of Atmospheric Variables -- The Fourier transform is an extremely useful tool in many areas of Physics, but ultimately has some limitations when dealing with finite data sets. We believe that use of wavelet analysis may make identification of transient phenomena in atmospheric time-series easier to identify and interpret.
6. Effects of Finite Sampling and Dead-Time on Statistical Inference -- The assumption of perfect spatial and temporal randomness (a.k.a. Poisson statistics) are ubiquitous in the natural sciences. However, this assumption is often made where it is not necessarily appropriate. (Even in the cases where we think a system must be perfectly random -- say radioactive decay -- often show non-Poisson effects when examined closely; for example, the Quantum Zeno Effect). Some of our work deals with what you can infer when the underlying statistics really aren't Poissonian in nature.
We actually have much, much more than this going on in our lab (including projects on Monte Carlo simulation of discrete spatial systems, environmental radiation monitoring, fabrication of instruments designed to measure atmospheric particulates individually, and studies associated with the physics of correlated spatial structures and how they effect radar returns), but nobody is going to read all of this. If you're interested in what we're doing or (better yet) might be interested in joining us, contact Dr. Larsen and he'll be glad to talk to you about our ongoing research.
- Alumni from the Larsen Atmospheric Physics Lab -(If you see your name here, I'd love to hear back from you and get an update on where you are and what you're doing!)
Tobin Barret (2010-2012) -- Studied radar returns to identify evidence of the urban heat island effect. (Working as an IT professional in California)
Josh Beck (2009-2010) -- Studied single raindrop detection techniques with focus on image edge detection. (Presumably graduated from University of Nebraska at Kearney, Spring 2011)
Phil Boehner (2010-2012) -- Studied computational stochastic geometry and computational simulations of radiative transfer. Primarily worked with the CUDA computing environment. (Enrolled in graduate studies at Florida State University).
Clarissa Briner (2011-2012) -- Studied how statistical measures change when sampling a 3d system with a semi-1d transect. (Enrolled in graduate studies at the University of Colorado).
Susanna Brylawski (2011-2012) -- Studied a means to make a relative humidity sensor using deliquescence. (Student at College of Charleston).
Dawn Carrillo (2008-2010) -- Studied environmental radiation. (Student at University of Nebraska at Kearney)
Jose Carrillo (2008-2010) -- Studied environmental radiation. (Student at University of Nebraska at Kearney)
Michael Chute (2012-2013) -- Studied aerosol mixing. (Civil Engineer with Flatiron)
Erin Deck (2011) -- Studied whether clouds can be used as an indicator of regional climate change. (Applying to graduate programs)
Benjamin Fullerton (2009-2010) -- Studied mechanical methods of detecting raindrops one drop at a time. (Student at University of Nebraska at Kearney)
David Hayes (2009-2010) -- Studied radiative transfer in correlated random media, worked on constructing an ad hoc cluster computing system. (Student at University of Nebraska at Kearney)
Kyle McClary (2008-2010) -- Studied acoustical methods of detecting rainfall one drop at a time. Also studied the effects of ethanol blends on engine wear. (Precision Farming Consultant at Greenline Equipment, Grand Island, NE)
Joshua Moravec (2010) -- Studied spatial properties of gamma ray bursts. (Student at University of Nebraska at Kearney)
Joseph Niehaus (2010-2011) -- Studied dose-response models for airborne pathogens. (Enrolled in graduate studies at Michigan Technological University)
Matt Noffke (2008-2010) -- Studied scaling properties of rainfall fluctuations and helped to develop some methods to detect rainfall one drop at a time. (Photographer for the Kearney Hub newspaper)
Danielle Policarpio (2009-2010) -- Studied capacitive properties of conductive fabrics. (Enrolled in graduate studies at Texas A&M University)
David Ruwadi (2011) -- Studied whether clouds can be used as an indicator of regional climate change. (Student at College of Charleston)
Grant Saltzgaber (2007-2010) -- Studied rainfall accumulation variability, scale-invariant properties of rainfall. (finished M.S. at Oregon State, now at Jireh Semiconductor in Oregon)
Adrian Sanabria-Diaz (2009-2010) -- Studied wavelet decomposition of sounds for acoustical fingerprinting. (Student at University of Nebraska at Kearney)
Cameron Self (2010-2011) -- Studyied the temporal behavior of wind in the atmospheric boundary layer. (Enrolled in graduate studies at UNC-Charlotte)
Jenn Smaroff (2010-2011) -- Studied spatial properties of tornado outbreaks. (Student at College of Charleston)
Conor Smith (2010-2011) -- Studied different methods of measuring rainfall one drop at a time and developed techniques to make "calibration" raindrops. (Enrolled in graduate studies at the University of Miami)
Aaron Steele (2008-2009) -- Studied wind in the atmospheric boundary layer and radiative transfer through correlated random media. (Completed M.S. at Miami University of Ohio, enrolled as a Ph.D. student at Notre Dame)
Jeremy Stromer (2009) -- Studied optical properties of Lyotropic Chromonic Liquid Crystals (Enrolled in graduate studies at the University of Connecticut)