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Christopher Ruf | Faculty

Christopher Ruf

Professor: Atmospheric, Oceanic and Space Sciences, Electrical Engineering and Computer Science

1521C SRB 

(734)764-6561

Profile Story


Back in the early 1980s, a rock band called White Noise enjoyed a burst of popularity on the Portland club and frat party circuit. The band cut one album, saw some radio air time and enjoyed a measure of regional success but was never able to cultivate a following beyond the Pacific Northwest.

For that, the planet should probably be grateful. Because instead of becoming a rock star, White Noise lead guitarist Chris Ruf became a key player in weather and climate research.  

Ruf, a professor of Atmospheric Science and Electrical Engineering, directs the Remote Sensing group at Michigan, building instruments and developing algorithms that give us information about earth’s weather and climate collected from vantage points in space.

He also leads a $150 million NASA mission, the Cyclone Global Navigation Satellite System (CYGNSS), that will use a constellation of eight small weather satellites to better understand and predict hurricanes.

But it all began with rock and roll. During White Noise’s heyday, Ruf started designing amplifiers, mixers and synthesizers for the band and discovered a passion for working with electronics and troubleshooting problems. He had an undergraduate degree in physics, but when the band broke up, he headed to the University of Massachusetts to study electrical engineering.

Ruf’s advisor at UMass, Calvin Swift, had recently left NASA after 20 years, and Swift’s connections put his students in a position to work on NASA projects right away. Ruf went on to spend three years at the NASA Jet Propulsion Laboratory in Pasadena, where he helped develop the satellite instrument that still gives us our most reliable sea level measurements.

Ruf left Southern California to get away from the smog and came to Michigan in 2000. He led U-M’s Space Physics Research Lab (SPRL) from 2006 until the spring of 2015. Instruments built at SPRL during his tenure are hard at work across the solar system, including the mass spectrometer on the Mars Curiosity rover and an instrument on the Messenger spacecraft that detected unexpected water around Mercury.

More recently, the lab has turned attention to building instruments for the smaller “cubesats,” that, until the CYGNSS project, haven’t been used for heavy-duty data-gathering. Typical large weather satellites are about the size of a bus; average size satellites are the size of a car. Each of the eight satellites in the CYGNSS program are about the size of a microwave oven.

Because they’re smaller, they’re less expensive, which means the mission can afford to send eight of them into orbit.  A single satellite can measure any location once every two or three days, but eight CYGNSS cubesats, when positioned just right, will be able to capture measurements from any region of the planet about once every 12 minutes and any location every six hours or so.

That’ll allow researchers to see how tropical cyclones develop into hurricanes and make more informed predictions that will, hopefully, help people get out of the way.

The mission also represents a different way of doing things for NASA, which has worked with university researchers for years but has never put an entire mission in the hands of a university professor - until now.

“When I talk to people I know in Europe, they’ve told me they think its crazy,” Ruf said. “But if it works well, the thinking is this is a new paradigm for doing lower cost missions that are managed outside the NASA inner circle. It has the potential to become a long-lasting new option for how to do missions, and it’s really exciting to be part of that or to be leading it.”

Because satellites go around the planet, Ruf’s professional network does too. He frequently works with academics and space agencies in Europe and Japan to ensure that his instruments are working the way they’re supposed to, and he collaborates with ground station operators in other parts of the world.

And in addition to the science and technology that have always been at the heart of his work, Ruf has also advised federal agencies on behalf of the National Academy of Sciences, helping to ensure scientific devices like weather satellites receive an appropriate share of the radio spectrum.

“There’s the whole global climate change and anthropogenic forcing vs. natural cycles side of it - the societal relevance of the work,” he said. “It’s nice to know you’re doing something useful and helping to figure out what’s wrong with the world. I guess somebody else is going to figure out how to fix the problems, but at least I’m characterizing what the problems are very carefully.”

Short Bio

EDUCATION

University of Massachusetts, Amherst
PhD Electrical & Computer Engineering '87

Reed College
BA Physics '82

ACADEMIC APPOINTMENTS

Associate Professor/Professor
Departments of AOSS and EECS
University of Michigan, Ann Arbor, MI July 2000 – Present

Director
Space Physics Research Laboratory
University of Michigan, Ann Arbor, MI May 2006-Jan 2015

Guest Professor
Department of Electromagnetic Systems 
Technical University of Denmark, Lyngby, DK Sep 2000 – Dec 2000 

Assistant/Associate Professor
Department of Electrical Engineering
Pennsylvania State University, University Park, PA Jan 1992 - Jun 2000 

Visiting Professor and Research Engineer
Dept. Electrical and Computer Engineering
University of Massachusetts, Amherst, MA Jun 1987 - Jun 1988 

Graduate Research Assistant
Microwave Remote Sensing Lab
Dept. Electrical and Comp. Eng.,
Univ. Massachusetts, Amherst, MA Sep 1983 - May 1987 

 


Research

  • Earth Environmental Remote Sensing:
    • Global Navigation Satellite System Mission Execution
    • Design and fabrication of next-generation satellite microwave radiometers
    • Novel methods for maintaining high accuracy and stability calibration of satellite sensors to detect minute global change signatures
    • Application of inversion techniques and multi-sensor assimilation to remote sensing
    •  Hardware and algorithmic aspects of satellite microwave radiometry
  • Synthetic thinned aperture radiometry
  • Mitigation of radio frequency interference
  • Self-contained end-to-end radiometer calibration system
  • Use of stationary statistical properties of upwelling radiances to constrain absolute accuracy and long term stability of satellite measurements
  • Profiling of lower, middle and upper atmosphere using multispectral, multisensor and climatological databases

Honors

  • 2006 International Geoscience and Remote Sensing Symposium Prize Paper Award for Detection of RFI by its Amplitude Probability Distribution
  • Instrument Scientist, NASA TOPEX Microwave Radiometer
  • Principle Investigator, calibration/validation of US Navy GEOSAT Follow-On Water Vapor Radiometer
  • Science Team Member, NASA Jason-1 Microwave Radiometer
  • Science Team Member, NASA Aquarius Microwave Radiometer
  • Developed new method for estimating the depth of the marine boundary layer (BLD) from space using horizontal turbulence structure of vertically integrated atmospheric water vapor
  • Developed new method for absolute and relative calibration of spaceborne microwave radiometers using lower bound on a cumulative statistic of the measured radiance
  • Advanced technologies in support of synthetic thinned aperture radiometer (STAR) in space (antenna arrays, real/synthetic aperture sharing, digital correlators, calibration techniques)
  • Derived correction to standard model for pressure broadening of atmospheric absorption line of water vapor at 22.235 GHz based on microwave spectrometer observations
  • Fellow, IEEE (2001)
  • IEEE Judith A. Resnik Technical Field Award, Contributions to the absolute calibration of spaceborne microwave radiometers (1999)
  • IEEE Transactions on Geoscience & Remote Sensing Prize Paper Award, Retrieval of tropospheric water vapor scale height from horizontal turbulence (1997)
  • NASA Group Achievement Award, Juno Proposal Team (2012)
  • NASA Group Achievement Award, Aquarius Launch, Early Orbit Operations, and Commissioning (2012)
  • NASA Group Achievement Award, Genesis and Rapid Intensification Processes (GRIP) Airborne Earth Science Mission (2011)
  • NASA Group Achievement Award, Lightweight Rainfall Radiometer (2004)
  • NASA Group Achievement Award, TOPEX Joint Verification Team (1994)
  • NASA Group Achievement Award, TOPEX precision orbit determination (1993)
  • NASA Group Achievement Award, TOPEX Microwave Radiometer (1993)
  • NASA Certificate of Recognition, Piezoelectric reflecting array for reflector surface distortion compensation (1992)
  • NASA Certificate of Recognition, Synthetic aperture interferometric radiometer image reconstruction error analysis (1992)
  • NASA Certificate of Recognition, Sparse aperture interferometric radiometer - Refining the two-dimensional antenna configuration (1990)

Publications


Chen, D.
, and C. S. Ruf, “Adaptive Control of Undetected Radio Frequency Interference with a Spaceborne Microwave Radiometer, IEEE Trans. Geosci. Remote Sens., doi: 10.1109/TGRS.2015.2414395, 2015.

Clarizia, M. P., Ruf, C.; Jales, P. and Gommenginger, C., “Spaceborne GNSS-R Minimum Variance Wind Speed Estimator,” IEEE Trans Geosci. Remote Sens., 52(11), 6829-6843, doi: 10.1109/TGRS.2014.2303831, Nov. 2014.

Yang, J. X., D. S. McKague and C. S. Ruf, “Land contamination correction for passive microwave radiometer data: Demonstration of wind retrieval in the Great Lakes using SSM/I,” J. Atmos. Oceanic. Tech., 31, doi:10.1175/JTECH-D-13-00254.1, Oct. 2014.

Le Vine, D.M., P. de Matthaeis, C. Ruf and D. Chen, “Aquarius RFI Detection and Mitigation: Assessment and Examples,” IEEE Trans. Geosci. Remote Sens., 52(8), 4574-4584, doi: r 10.1109/TGRS.2013.2282595, Aug. 2014.

Piepmeier, J. R., J. T. Johnson, P. N. Mohammed, D. Bradley, C. Ruf, M. Aksoy, R. Garcia, D. Hudson, L. Miles and M. Wong, “Radio-Frequency Interference Mitigation for the Soil Moisture Active Passive Microwave Radiometer,” . IEEE Trans. Geosci. Remote Sens., 52(1), 761-775, doi: 10.1109/TGRS.2013.2281266, Jan. 2014.

Kroodsma, R., D. McKague and C. S. Ruf, “Extension of Vicarious Cold Calibration to 85-92 GHz forYang, J. X., D. S. McKague and C. S. Ruf, “Land contamination correction for passive microwave radiometer data: Demonstration of wind retrieval in the Great Lakes using SSM/I,” J. Atmos. Oceanic. Tech., 31, doi:10.1175/JTECH-D-13-00254.1, Oct. 2014. Spaceborne Microwave Radiometers,” IEEE Trans Geosci. Remote Sens., 51(9), 4743-4751doi: 10.1109/TGRS.2013.2267152,Sep. 2013.

Meadows, L.A. C. Whelan, D. Barrick, R. Kroodsma, C. Ruf, C.C. Teague, G.A. Meadows and S. Wang, “High Frequency Radar and its Application to Fresh Water,” J. Great Lakes Research, doi:10.1016/j.jglr.2013.01.002, Mar 2013.

Renno, N. O., and C.S. Ruf, “Comments on the Search for Electrostatic Discharges on Mars,” The Astrophysical Journal, 761:88, doi:10.1088/0004-637X/761/2/88, Dec 2012.

Misra, S., R.D. De Roo and C.S. Ruf, “An Improved Radio Frequency Interference Model: Reevaluation of the Kurtosis Detection Algorithm Performance under Central-Limit Conditions,” IEEE Trans. Geosci. Remote Sens., 50(11), 4565-4574, doi:10.1109/TGRS.2012.2191972, 2012.

Misra, S., and C.S. Ruf, “Analysis of Radio Frequency Interference Detection Algorithms in the Angular Domain for SMOS,” IEEE Trans. Geosci. Remote Sens., 50(5), 1448-1457, doi:10.1109/TGRS.2011.2176949, 2012.

Complete list