Todd Hoefen
Todd Hoefen is a Geophysicist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 112
Mapping the distribution of materials in hyperspectral data using the USGS Material Identification and Characterization Algorithm (MICA) Mapping the distribution of materials in hyperspectral data using the USGS Material Identification and Characterization Algorithm (MICA)
Identifying materials by measuring and analyzing their reflectance spectra has been an important method in analytical chemistry for decades. Airborne and space-based imaging spectrometers allow scientists to detect materials and map their distributions across the landscape. With new satellite-borne hyperspectral sensors planned for the future, for example, HYSPIRI (HYPerspectral InfraRed...
Authors
Raymond F. Kokaly, T. V. V. King, Todd M. Hoefen
Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes
In 2007-09, California experienced several large wildfires that damaged large areas of forest and destroyed many homes and buildings. The U.S. Geological Survey collected samples from the Harris, Witch, Grass Valley, Ammo, Santiago, Canyon, Jesusita, and Station fires for testing to identify any possible characteristics of the ashes and soils from burned areas that may be of concern for...
Authors
Ruth E. Wolf, Todd M. Hoefen, Philip L. Hageman, Suzette A. Morman, Geoffrey S. Plumlee
Detection and mapping of hydrocarbon deposits on Titan Detection and mapping of hydrocarbon deposits on Titan
We report the identification of compounds on Titan's surface by spatially resolved imaging spectroscopy methods through Titan's atmosphere, and set upper limits to other organic compounds. We present evidence for surface deposits of solid benzene (C6H6), solid and/or liquid ethane (C2H6), or methane (CH4), and clouds of hydrogen cyanide (HCN) aerosols using diagnostic spectral features...
Authors
Roger N. Clark, J. M. Curchin, Jason W. Barnes, Ralf Jaumann, Laurence A. Soderblom, Dale P. Cruikshank, Robert H. Brown, Sebastien Rodriguez, Jonathan Lunine, Katrin Stephan, Todd M. Hoefen, Stephane Le Mouelic, Christophe Sotin, Kevin H. Baines, Bonnie J. Buratti, Philip D. Nicholson
A method for quantitative mapping of thick oil spills using imaging spectroscopy A method for quantitative mapping of thick oil spills using imaging spectroscopy
In response to the Deepwater Horizon oil spill in the Gulf of Mexico, a method of near-infrared imaging spectroscopic analysis was developed to map the locations of thick oil floating on water. Specifically, this method can be used to derive, in each image pixel, the oil-to-water ratio in oil emulsions, the sub-pixel areal fraction, and its thicknesses and volume within the limits of...
Authors
Roger N. Clark, Gregg A. Swayze, Ira Leifer, K. Eric Livo, Raymond F. Kokaly, Todd Hoefen, Sarah Lundeen, Michael Eastwood, Robert O. Green, Neil Pearson, Charles Sarture, Ian McCubbin, Dar Roberts, Eliza Bradley, Denis Steele, Thomas Ryan, Roseanne Dominguez
A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data
This report describes a method to create color-composite images indicative of thick oil:water emulsions on the surface of clear, deep ocean water by using normalized difference ratios derived from remotely sensed data collected by an imaging spectrometer. The spectral bands used in the normalized difference ratios are located in wavelength regions where the spectra of thick oil:water...
Authors
Raymond F. Kokaly, Todd M. Hoefen, K. Eric Livo, Gregg A. Swayze, Ira Leifer, Ian B. McCubbin, Michael L. Eastwood, Robert O. Green, Sarah R. Lundeen, Charles M. Sarture, Denis Steele, Thomas Ryan, Eliza S. Bradley, Dar A. Roberts
Estimated minimum discharge rates of the Deepwater Horizon spill— Interim report to the flow rate technical group from the Mass Balance Team Estimated minimum discharge rates of the Deepwater Horizon spill— Interim report to the flow rate technical group from the Mass Balance Team
All of the calculations and results in this report are preliminary and intended for the purpose, and only for the purpose, of aiding the incident team in assessing the extent of the spilled oil for ongoing response efforts. Other applications of this report are not authorized and are not considered valid. Because of time constraints and limitations of data available to the experts, many...
Authors
Victor F. Labson, Roger N. Clark, Gregg A. Swayze, Todd M. Hoefen, Raymond F. Kokaly, K. Eric Livo, Michael H. Powers, Geoffrey S. Plumlee, Gregory P. Meeker
Science and Products
Filter Total Items: 112
Mapping the distribution of materials in hyperspectral data using the USGS Material Identification and Characterization Algorithm (MICA) Mapping the distribution of materials in hyperspectral data using the USGS Material Identification and Characterization Algorithm (MICA)
Identifying materials by measuring and analyzing their reflectance spectra has been an important method in analytical chemistry for decades. Airborne and space-based imaging spectrometers allow scientists to detect materials and map their distributions across the landscape. With new satellite-borne hyperspectral sensors planned for the future, for example, HYSPIRI (HYPerspectral InfraRed...
Authors
Raymond F. Kokaly, T. V. V. King, Todd M. Hoefen
Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes Speciation of arsenic, selenium, and chromium in wildfire impacted soils and ashes
In 2007-09, California experienced several large wildfires that damaged large areas of forest and destroyed many homes and buildings. The U.S. Geological Survey collected samples from the Harris, Witch, Grass Valley, Ammo, Santiago, Canyon, Jesusita, and Station fires for testing to identify any possible characteristics of the ashes and soils from burned areas that may be of concern for...
Authors
Ruth E. Wolf, Todd M. Hoefen, Philip L. Hageman, Suzette A. Morman, Geoffrey S. Plumlee
Detection and mapping of hydrocarbon deposits on Titan Detection and mapping of hydrocarbon deposits on Titan
We report the identification of compounds on Titan's surface by spatially resolved imaging spectroscopy methods through Titan's atmosphere, and set upper limits to other organic compounds. We present evidence for surface deposits of solid benzene (C6H6), solid and/or liquid ethane (C2H6), or methane (CH4), and clouds of hydrogen cyanide (HCN) aerosols using diagnostic spectral features...
Authors
Roger N. Clark, J. M. Curchin, Jason W. Barnes, Ralf Jaumann, Laurence A. Soderblom, Dale P. Cruikshank, Robert H. Brown, Sebastien Rodriguez, Jonathan Lunine, Katrin Stephan, Todd M. Hoefen, Stephane Le Mouelic, Christophe Sotin, Kevin H. Baines, Bonnie J. Buratti, Philip D. Nicholson
A method for quantitative mapping of thick oil spills using imaging spectroscopy A method for quantitative mapping of thick oil spills using imaging spectroscopy
In response to the Deepwater Horizon oil spill in the Gulf of Mexico, a method of near-infrared imaging spectroscopic analysis was developed to map the locations of thick oil floating on water. Specifically, this method can be used to derive, in each image pixel, the oil-to-water ratio in oil emulsions, the sub-pixel areal fraction, and its thicknesses and volume within the limits of...
Authors
Roger N. Clark, Gregg A. Swayze, Ira Leifer, K. Eric Livo, Raymond F. Kokaly, Todd Hoefen, Sarah Lundeen, Michael Eastwood, Robert O. Green, Neil Pearson, Charles Sarture, Ian McCubbin, Dar Roberts, Eliza Bradley, Denis Steele, Thomas Ryan, Roseanne Dominguez
A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data
This report describes a method to create color-composite images indicative of thick oil:water emulsions on the surface of clear, deep ocean water by using normalized difference ratios derived from remotely sensed data collected by an imaging spectrometer. The spectral bands used in the normalized difference ratios are located in wavelength regions where the spectra of thick oil:water...
Authors
Raymond F. Kokaly, Todd M. Hoefen, K. Eric Livo, Gregg A. Swayze, Ira Leifer, Ian B. McCubbin, Michael L. Eastwood, Robert O. Green, Sarah R. Lundeen, Charles M. Sarture, Denis Steele, Thomas Ryan, Eliza S. Bradley, Dar A. Roberts
Estimated minimum discharge rates of the Deepwater Horizon spill— Interim report to the flow rate technical group from the Mass Balance Team Estimated minimum discharge rates of the Deepwater Horizon spill— Interim report to the flow rate technical group from the Mass Balance Team
All of the calculations and results in this report are preliminary and intended for the purpose, and only for the purpose, of aiding the incident team in assessing the extent of the spilled oil for ongoing response efforts. Other applications of this report are not authorized and are not considered valid. Because of time constraints and limitations of data available to the experts, many...
Authors
Victor F. Labson, Roger N. Clark, Gregg A. Swayze, Todd M. Hoefen, Raymond F. Kokaly, K. Eric Livo, Michael H. Powers, Geoffrey S. Plumlee, Gregory P. Meeker