Earth
and Space Sciences Faculty |
|
Brian
Swanson |
Areas of Interest:
Atmospheric and Cloud Physics
Research Group:
Atmospheric and Cloud Physics
Education:
Ph.D., Physics, University
of Washington, 1992
Current Research:
Latest Laboratory
Results Website
- Atmospheric
and Cloud Physics
- Ice
Particle Microphysics
- Ice Physics
1) Growth and Sublimation rates,
Habit Evolution and Light Scattering Properties of Ice Particles
My students and I
study the growth, sublimation and light scattering properties of tropospheric ice
particles. One of the instruments we use is a temperature and humidity controlled
electrodynamic balance (EDB) which allows us to observe single ice particles
away from the influence of surfaces. Our work focuses on growing and sublimating
ice particles in the laboratory under conditions
similar to those observed in nature. Recent results (Bacon and Swanson 2003) indicate that ice formation
processes that occur during droplet freezing apparently have a distinct influence on
particle habit. 2) Ice Nucleation
My students and I have developed
an instrument to observe the freezing of supercooled droplets in free-fall inside a freezing tube.
This instrument makes possible the observation of the freezing process with high repitition rates and away
from the influence and possible contamination of substrates. One of our studies
looks at the microphysics of homogeneous water solutions. Recent experiments measured the freezing
rate of droplets containing aqueous ammonium sulfate and sulfuric acid solutions. Our latest
experiments study the heterogeneous freezing process of bionucleants
like sea-ice bacteria. 3) Ions and Molecules near Surfaces
My students and I are interested in
the microphysics of ions and molecules that reside near an air-water or air-ice interface.
We have built a cryostat with an integral confocal microscope to measure the ion profile near
these interfaces. This instrument has been used for fluorescence microscopy and resonant
Raman spectroscopy studies of molecules at interfaces. Future studies will explore the
process of uptake of acid gases and other impurities into
ice. One goal is a better understanding of the microphysics of charge transfer which occurs
between colliding ice particles in the troposphere -- a process thought to be
responsible for thunderstorm electrification.
4) Sap Crystals We have been
looking at ice crystal formation on plant surfaces. Aside from Dock family plants
(shown in the Glaciology V. 39 (1993) -- photograph taken in Ladakh, India) we've recently found
other northwestern US trees that exhibit sap crystal formations but with a different
morphology. The goal is to better understand the formation mechanisms and the
extent to which these processes are responsible for frost damage in these plants. Selected Publications:
Graduate Students:
Postdoc:
List
of Publications
Brant Wilson (Chem. Eng.)
Ben Wearn (Physics)
Karen Junge
This work is supported by
grants from the National Science Foundation, the University of Washington Royalty
Research Fund, the University of Washington Program for Climate Change, and the
Leonard X. Bosack and Bette M. Kruger Charitable Foundation.
Last Modified: 5/10/2006
Earth and Space Sciences
(Geology, Geophysics, Geological Sciences)
University of Washington
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