My research interests focus on implementing novel lidar measurement, acquisition, and processing techniques to increase accuracy and precision of science retrievals, notably with instruments operating in the photon counting regime. I was funded by the NASA Earth and Space Sciences Fellowship to complete my Ph.D. at the University of Colorado Boulder focused on high resolution photon counting lidar development. I am currently research scientist at the NASA Langley Research Center working on the High Altitude Lidar Observatory, a novel multi-functional lidar sensor for methane, water vapor, and cloud and aerosol research.
My broad associated research interests include: lidar hardware development and theory, optical detection theory, airborne laser remote sensing for multiple geoscience discplines, atmospheric radiative transfer, polarized and non-polarized scatterometry, platform integration - including instrument structure and vibration analysis, and lidar specifics such as time-correlated single-photon counting. The list goes on.
Current Projects:
High Altitude Lidar Observatory (HALO) - NASA Langley Research Center's modular and multi-function airborne lidar developed to measure atmospheric water vapor and methane mixing ratios and aerosol/cloud/ocean optical properties using the DIAL and HSRL techniques, respectively. The HALO instrument also serves as a testbed for new and innovative technology solutions, allowing for rapid installation and deployment for aircraft evaluation.
Atmospheric Boundary-Layer Lidar PathfindEr (ABLE) - Technology advancement and mission concept development for a space borne water vapor and methane DIAL instrument. This projected was recently selected and funded under the NASA Earth Science Technology Office's Instrument Incubator Program.
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I was Co-Editor on a lidar-centric feature issue in the Optical Society of America's JOSA A/B journals, published Fall 2021.
Please visit: https://www.osapublishing.org/josaa/virtual_issue.cfm?vid=500
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I am currently the Vice-Chair of The American Meteorological Society's Committee on Laser Atmospheric Studies.
http://https//www.ametsoc.org/index.cfm/stac/committees/committee-on-laser-atmospheric-studies/terms-of-reference/
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Select journal publications and presentations:
"Evaluation of the High Altitude Lidar Observatory Methane Retrievals During the Summer 2019 ACT-America Campaign"
http://https//amt.copernicus.org/preprints/amt-2022-106/
"High resolution photon time-tagging lidar for atmospheric point cloud generation"
https://doi.org/10.1364/OE.26.026030
"Nonlinear target count rate estimation in single-photon lidar due to first photon bias"
https://doi.org/10.1364/OL.44.001249
"Airborne lidar observations of wind, water vapor, and aerosol profiles during the NASA Aeolus calibration and validation (Cal/Val) test flight campaign."
https://doi.org/10.5194/amt-14-4305-2021
"Differential absorption lidar measurements of water vapor by the High Altitude Lidar Observatory (HALO): retrieval framework and first results."
https://doi.org/10.5194/amt-15-605-2022
"The High Altitude Lidar Observatory (HALO): A multi-function lidar and technology testbed for airborne and space-based measurements of water vapor and methane"
NASA Earth Science Technology Office - 2018 Earth Science Technology Forum
https://esto.nasa.gov/forums/ESTF2018/presentations/Nehrir_ESTF2018_A1P2.pdf
"HALO XCH4 Retrievals During the 2019 ACT-America Campaign"
17th International Workshop on Greenhouse Gas Measurements From Space
https://cce-datasharing.gsfc.nasa.gov/files/conference_presentations/Poster_BartonGrimley_0_161_25.pdf
Ph.D. Dissertation Location
My broad associated research interests include: lidar hardware development and theory, optical detection theory, airborne laser remote sensing for multiple geoscience discplines, atmospheric radiative transfer, polarized and non-polarized scatterometry, platform integration - including instrument structure and vibration analysis, and lidar specifics such as time-correlated single-photon counting. The list goes on.
Current Projects:
High Altitude Lidar Observatory (HALO) - NASA Langley Research Center's modular and multi-function airborne lidar developed to measure atmospheric water vapor and methane mixing ratios and aerosol/cloud/ocean optical properties using the DIAL and HSRL techniques, respectively. The HALO instrument also serves as a testbed for new and innovative technology solutions, allowing for rapid installation and deployment for aircraft evaluation.
Atmospheric Boundary-Layer Lidar PathfindEr (ABLE) - Technology advancement and mission concept development for a space borne water vapor and methane DIAL instrument. This projected was recently selected and funded under the NASA Earth Science Technology Office's Instrument Incubator Program.
_________________________
I was Co-Editor on a lidar-centric feature issue in the Optical Society of America's JOSA A/B journals, published Fall 2021.
Please visit: https://www.osapublishing.org/josaa/virtual_issue.cfm?vid=500
_________________________
I am currently the Vice-Chair of The American Meteorological Society's Committee on Laser Atmospheric Studies.
http://https//www.ametsoc.org/index.cfm/stac/committees/committee-on-laser-atmospheric-studies/terms-of-reference/
_________________________
Select journal publications and presentations:
"Evaluation of the High Altitude Lidar Observatory Methane Retrievals During the Summer 2019 ACT-America Campaign"
http://https//amt.copernicus.org/preprints/amt-2022-106/
"High resolution photon time-tagging lidar for atmospheric point cloud generation"
https://doi.org/10.1364/OE.26.026030
"Nonlinear target count rate estimation in single-photon lidar due to first photon bias"
https://doi.org/10.1364/OL.44.001249
"Airborne lidar observations of wind, water vapor, and aerosol profiles during the NASA Aeolus calibration and validation (Cal/Val) test flight campaign."
https://doi.org/10.5194/amt-14-4305-2021
"Differential absorption lidar measurements of water vapor by the High Altitude Lidar Observatory (HALO): retrieval framework and first results."
https://doi.org/10.5194/amt-15-605-2022
"The High Altitude Lidar Observatory (HALO): A multi-function lidar and technology testbed for airborne and space-based measurements of water vapor and methane"
NASA Earth Science Technology Office - 2018 Earth Science Technology Forum
https://esto.nasa.gov/forums/ESTF2018/presentations/Nehrir_ESTF2018_A1P2.pdf
"HALO XCH4 Retrievals During the 2019 ACT-America Campaign"
17th International Workshop on Greenhouse Gas Measurements From Space
https://cce-datasharing.gsfc.nasa.gov/files/conference_presentations/Poster_BartonGrimley_0_161_25.pdf
Ph.D. Dissertation Location
View from the NASA DC8 over the Atlantic Ocean during the NASA CPEX-AW 2021 campaign.