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Dale Winebrenner

Senior Principal Physicist

Research Professor, Astrobiology Program and Earth & Space Sciences






Dr. Winebrenners' interests are in the physics of light and radio waves, and in the exploration of icy environments on Earth and elsewhere based on that physics.

For sea ice, he has developed a physically based method to observe the springtime melting and fall freeze-up transitions on Arctic sea ice using synthetic aperture radar, and has shown that polarimetric microwave backscattering from thin sea ice depends on ice thickness and thus may be useful for remote thickness estimation. Recently he has investigated the optical fluorescence from chlorophyll in sea ice, with the aim of estimating phototrophic biomass near the ice-water interface.

Microwave emissions are used to map (decadal-scale) mean surface temperature and accumulation rate fields, for ice sheet on both Greenland and Antarctica. Most recently, Dale Winebrenner has begun to investigate meter-wavelength radar sounding of ice sheets. The first result of this work is a new means of estimating electromagnetic absorption within the ice sheet.

Department Affiliation

Polar Science Center


B.S. Physics, Purdue University, 1979

M.S. Electrical Engineering, University of California, San Diego, 1980

Ph.D. Electrical Engineering, University of Washington, 1985


2000-present and while at APL-UW

Avoiding slush for hot-point drilling of glacier boreholes

Hills, B.H., D.P. Winebrenner, W.T. Elam, and P.M.S. Kintner, "Avoiding slush for hot-point drilling of glacier boreholes," Ann. Glaciol., 62, 166-170, doi:10.1017/aog.2020.70, 2021.

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1 Apr 2021

Water-filled boreholes in cold ice refreeze in hours to days, and prior attempts to keep them open with antifreeze resulted in a plug of slush effectively freezing the hole even faster. Thus, antifreeze as a method to stabilize hot-water boreholes has largely been abandoned. In the hot-point drilling case, no external water is added to the hole during drilling, so earlier antifreeze injection is possible while the drill continues melting downward. Here, we use a cylindrical Stefan model to explore slush formation within the parameter space representative of hot-point drilling. We find that earlier injection timing creates an opportunity to avoid slush entirely by injecting sufficient antifreeze to dissolve the hole past the drilled radius. As in the case of hot-water drilling, the alternative is to force mixing in the hole after antifreeze injection to ensure that ice refreezes onto the borehole wall instead of within the solution as slush.

Phase function effects on identification of terahertz spectral signatures using the discrete wavelet transform

Khani, M.E., D.P. Winebrenner, and M.H. Arbab, "Phase function effects on identification of terahertz spectral signatures using the discrete wavelet transform," IEEE Trans. Terahertz Sci. Technol., 10, 656-666, doi:10.1109/TTHZ.2020.2997595, 2020.

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1 Nov 2020

We describe the application of the discrete wavelet transform (DWT) in extracting the characteristic absorption signatures of materials from terahertz reflection spectra. We compare the performance of different mother wavelets, including Daubechies, least asymmetric (LA), and Coiflet, based on their phase and gain functions and filter lengths. We show that the phase functions of the wavelet and scaling filters result in spectral shifts to the absorption lines in the wavelet domain. We provide a solution by calculating advancement coefficients necessary to achieve effective zero-phase-function DWT. We demonstrate the utility of this signal processing technique using α-lactose monohydrate/polyethylene samples with different levels of rough surface scattering. In all cases, the DWT-based algorithm successfully extracts resonant signatures at 0.53 and 1.38 THz, even when they are obscured by the rough surface scattering effects. The DWT analysis with accompanying phase corrections can be utilized as a robust technique for material identification in nondestructive evaluation using terahertz spectroscopy.

Terahertz time-domain polarimetry (THz-TDP) based on the spinning E-O sampling technique: Determination of precision and calibration

Xu, K., E. Bayati, K. Oguchi, S. Watanabe, D.P. Winebrenner, and M.H. Arbab, "Terahertz time-domain polarimetry (THz-TDP) based on the spinning E-O sampling technique: Determination of precision and calibration," Opt. Express, 28, 13,482-13,496, doi:10.1364/OE.389651, 2020.

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27 Apr 2020

We have developed a terahertz time-domain polarimetry (THz-TDP) system by applying frequency modulation to electro-optic sampling detection in a nonlinear crystal. We characterized the precision of this system in determining the polarization angles to be 1.3° for fixed time delay, and 0.5° for complete time-domain waveform. Furthermore, we calculated the Jones matrix of the optical components used for beam propagation to calibrate the induced systematic error. The advantages of employing this calibration approach are demonstrated on a sapphire crystal investigated at different sample test positions in transmission configuration, and using high resistivity Si, AlN and quartz in reflection geometry. The new THz-TDP technique has the advantage of not using any external polarizers, and therefore is not constrained by their optical performance limitations, such as restricted bandwidths and frequency-dependent extinction ratio. Finally, the THz-TDP technique can be easily implemented on existing time-domain spectroscopy (TDS) systems.

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In The News

UW part of $25M NSF-funded effort to retrieve Earth’s oldest ice core

UW News

The new Center for Oldest Ice Exploration, or COLDEX, will be created under a five-year, $25 million National Science Foundation grant. Roughly $5 million of that grant will go to the UW. One aspect of COLDEX will involve new development of a probe, the Ice Diver, that melts through layers of ice and provides information about the age of the ice and other data without having to lift a core back up to the surface.

14 Sep 2021

Researchers test ice probe on Mount Baker

Skagit Valley Herald, Kimberly Cauvel

APL-UW researchers received help from a local snowmobile club to reach Mount Baker's Easton Glacier at an elevation of about 8000 feet to conduct tests of the 'ice diver' probe — an electrically-heated instrument that pierces glacial ice to measure the physical and biological environments below.

15 Jun 2019

The ice of a distant moon

Science News, Meghan Rosen

Scientists around the world are trying to figure out how to pierce the thick, icy shell of Europa to search for life below. Dale Winebrenner is quoted.

2 May 2014

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Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center