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Mikael K. Witte

PhD in Atmospheric Physics

Summary

Clouds are the single greatest source of uncertainty in predicting future climate change. My research explores the fundamental physics of how warm clouds and precipitation form using a combination of measurements (both remotely sensed and in situ) and large eddy simulations. My teaching aims to encourage critical numeracy and engage learners with the fundamentals of climate science as well as the societal implications of our interactions with the environment.

Research Experience

Jun 2012Jun 2016

PhD Dissertation Research

University of California, Santa Cruz
  • Processed and analyzed microphysical, turbulent, and thermodynamic measurements from 2008 Physics of Stratocumulus Tops (POST) flight campaign
  • Developed a quasi-inverse method for comparing model output with aircraft microphysical measurements, implemented in MATLAB
  • Extensively modified the bin microphysics scheme of RAMS-LES to incorporate an inhomogeneous entrainment mixing scheme, a turbulent collection kernel and a high spectral resolution collision-coalescence subroutine
Jul 2015

ARM Summer Training and Science Applications Workshop

National Weather Center, Norman, OK, USA
  • Participated in a summer school with lectures on various remote sensing instruments (Doppler radar, lidar, radiometers, etc.) and engaged in original small group work
  • Voted "Best Presentation" by workshop instructors for work on early diagnosis of drizzle onset in marine stratocumulus using vertically-pointing Doppler radar
Nov 2011Aug 2013

DYNAMO Field Project Assistant

Diego Garcia, British Indian Ocean Territory

DYNAMO was a multinational tropical meteorology experiment to study the Madden-Julian Oscillation which took place during Nov-Dec 2011. As part of the project, I was responsible for the following:

  • Calibrated and maintained DMT CIP, PIP, and CDP instruments over 12 research flights with the NOAA P3 "Miss Piggy"
  • Processed and analyzed microphysical measurements, including a rewrite of the CIP/PIP processing scripts
20092012

Graduate Research Assistant

University of California, Santa Cruz

Prior to beginning thesis research, I worked on a number of small projects:

  • Worked with Professor Ian Faloona (University of California, Davis) to set up an off-grid atmospheric monitoring site at Chews Ridge near Carmel Valley, CA
    • Designed and purchased monitoring instruments (O3, CO, and aerosol) as well as electronic, electrical, and cooling equipment subject to the constraints of low power consumption and small physical footprint
    • Calibrated and installed instruments on-site
  • Analyzed large eddy simulation output to characterize the life cycle of shallow cumulus clouds, resulting in a refereed publication (see below)
  • Performed a principal component analysis on microphysical, dynamic, and thermodynamic measurements from multiple field campaigns to yield insights into precipitation formation in marine stratocumulus

Education

Sep 2009Jun 2016

PhD, Earth and Planetary Sciences

University of California, Santa Cruz

Dissertation title: Observational and modeling studies of collision-coalescence in marine stratocumulus.

Dissertation advisor: Dr. Patrick Y. Chuang

20042008

BA, Physics and Mathematics

St. Olaf College

Graduated magna cum laude  with honors in physics

Refereed Publications

M.K. Witte, T.L. Yuan, and P.Y. Chuang, “Comparison of aircraft measurements and MODIS retrievals of cloud-top effective radius,” in preparation

M.K. Witte, O. Ayala, L.P. Wang, J.L. Petters and P.Y. Chuang, “Can turbulent collision-coalescence improve simulations of marine stratocumulus?” in preparation

M.K. Witte, O. Ayala, L.P. Wang, G. Feingold and P.Y. Chuang, “The role of microphysical spectral resolution in simulations of marine stratocumulus,”  in preparation 

M.K. Witte, O. Ayala, L.P. Wang, A. Bott, and P.Y. Chuang, “Estimating collision rates from observations of marine stratocumulus,”  to be submitted June 2016

N. Guy, D. P. Jorgensen, M. K. Witte, and P. Y. Chuang, "In situ airborne observations of rain drop distributions during DYNAMO," to be submitted to Mon. Wea. Rev.

M. K. Witte, P. Y. Chuang and G. Feingold, "On Clouds and Clocks," Atmos. Chem. Phys., 14:6729-6738, 2014

M. M. Dummer, K. Johnson, M. K. Witte, W. K. Hogan, and M. Hibbs-Brenner, "Computed radiography imaging based on high-density 670-nm VCSEL arrays," Proc. SPIE. 7557, Multimodal Biomedical Imaging V, 75570H, 2010

Conference Presentations

M. K. Witte, P. Y. Chuang, L. P. Wang, O. Ayala and D. L. Rossiter, "Constraining precipitation initiation in marine stratocumulus using aircraft observations and LES with high spectral resolution bin microphysics," poster presentation, AGU Fall Meeting, San Francisco, CA, 18 December 2015

M. K. Witte and P. Y. Chuang, "The role of turbulence in precipitation initiation," poster presentation, Cloud Feedback Model Intercomparison Project meeting, Monterey, CA, 10 June 2015

M .K. Witte, P. Y. Chuang, L. P. Wang and O. Ayala, “What controls drizzle initiation? Insights from a comparison of large-eddy simulations with observations,” oral presentation, AGU Fall Meeting, San Francisco, CA, 18 December 2014

M. K. Witte, P. Y. Chuang, O. Ayala and L. P. Wang, “Applying an inverse method to estimate collision-coalescence rates from aircraft observations,” oral presentation, 14th Conference on Cloud Physics, Boston, MA, 7 July 2014

M. K. Witte, P. Y. Chuang and D. L. Rossiter, “Analysis of marine stratocumulus drizzle using in situ observations,” poster presentation, AGU Fall Meeting, San Francisco, CA, 12 December 2013

M. K. Witte, P. Y. Chuang, G. Feingold and H. Jiang, “A small cumulus cloud clock from in situ measurements,” oral presentation, AGU Fall Meeting, 7 December 2012

M. K. Witte and P. Y. Chuang, “Can in situ measurements be used to estimate the age of shallow cumulus clouds?” poster presentation, AGU Fall Meeting, 13 December 2010 

M. K. Witte, D. L. Rossiter and P. Y. Chuang, “Principal component analysis of marine stratocumulus drizzle and other in situ observations,” poster presentation, 13th Conference on Cloud Physics, 30 June 2010

Teaching Experience

  • UNIVERSITY OF CALIFORNIA, SANTA CRUZ
    • GRADUATE STUDENT INSTRUCTOR
      • Environmental Geology, Summer 2012
        • Taught 20 undergraduate students, both earth science majors and others. Designed and implemented curriculum, delivered lectures, and assigned and graded reading and homework assignments as well as a cumulative assessment task.
    • TEACHING ASSISTANT
      • The Atmosphere, Winter 2011, 2013 and 2015
        • Taught discussion sections of a calculus-based atmospheric science overview course. Refreshed students on basic fluid mechanics and thermodynamics and graded and helped develop weekly problem sets.
      • Fundamentals of Environmental Science, Winter 2014
      • Introductory Physics Laboratory: Electricity and Magnetism, Summer 2012
      • Introduction to Weather and Climate, Spring 2012
      • Planetary Discovery, Winter 2010
  • SAINT OLAF COLLEGE

    • LABORATORY TEACHING ASSISTANT
      • Analytical Physics I, Fall 2005, Fall 2006, Fall 2007
        • Introduced groups of 10-20 first-year undergraduate physics majors to the laboratory setting and taught the basics of lab notebook usage, error propagation, basic programming in Python, and introductory calculus-based classical and wave mechanics.

Skills

MATLAB
Data analysis
Large eddy simulation
FORTRAN
Cloud probe instrumentation
Python