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My general research interests fall within the environment remote sensing area with a focus on implementing novel hardware, measurement, and processing techniques to increase accuracy and precision of science retrievals or provide access to retrievals of new geophysical variables. I completed my Ph.D. at the University of Colorado Boulder, funded by the NASA Earth and Space Sciences Fellowship, working with lidar instrumentation and measurement theory. I am currently a research scientist at the NASA Langley Research Center working with novel multi-functional lidar instruments for methane, water vapor, and cloud and aerosol research.
Topics I am interested in: lidar hardware development and theory, optical detection theory, airborne laser remote sensing for multiple geoscience disciplines, atmospheric radiative transfer, global observing system simulation, sparse signal detection in noisy environments, and more.
Current Projects (PI, CO-I, Collaborator):
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 project also has a large model driven portion to look at performance capabilities of future instrumentation with high fidelity airborne lidar derived scenes and global nature runs. This projected was recently selected and funded under the NASA Earth Science Technology Office's Instrument Incubator Program.
NASA Decadal Survey Incubation - Combining Lidar Profiles of Aerosol and Water Vapor to Determine PBL Height
NASA Decadal Survey Incubation - An OSSE Framework for the NASA PBL Decadal Survey Incubation Activity
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I am currently the Vice-Chair of The American Meteorological Society's Committee on Laser Atmospheric Studies.
https://www.ametsoc.org/index.cfm/stac/committees/committee-on-laser-atmospheric-studies/
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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Select journal publications and presentations:
"Evaluation of the High Altitude Lidar Observatory Methane Retrievals During the Summer 2019 ACT-America Campaign"
https://doi.org/10.5194/amt-15-4623-2022
"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
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Ph.D. Dissertation Location
My general research interests fall within the environment remote sensing area with a focus on implementing novel hardware, measurement, and processing techniques to increase accuracy and precision of science retrievals or provide access to retrievals of new geophysical variables. I completed my Ph.D. at the University of Colorado Boulder, funded by the NASA Earth and Space Sciences Fellowship, working with lidar instrumentation and measurement theory. I am currently a research scientist at the NASA Langley Research Center working with novel multi-functional lidar instruments for methane, water vapor, and cloud and aerosol research.
Topics I am interested in: lidar hardware development and theory, optical detection theory, airborne laser remote sensing for multiple geoscience disciplines, atmospheric radiative transfer, global observing system simulation, sparse signal detection in noisy environments, and more.
Current Projects (PI, CO-I, Collaborator):
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 project also has a large model driven portion to look at performance capabilities of future instrumentation with high fidelity airborne lidar derived scenes and global nature runs. This projected was recently selected and funded under the NASA Earth Science Technology Office's Instrument Incubator Program.
NASA Decadal Survey Incubation - Combining Lidar Profiles of Aerosol and Water Vapor to Determine PBL Height
NASA Decadal Survey Incubation - An OSSE Framework for the NASA PBL Decadal Survey Incubation Activity
____________________________________________________________________________________________________
I am currently the Vice-Chair of The American Meteorological Society's Committee on Laser Atmospheric Studies.
https://www.ametsoc.org/index.cfm/stac/committees/committee-on-laser-atmospheric-studies/
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
____________________________________________________________________________________________________
Select journal publications and presentations:
"Evaluation of the High Altitude Lidar Observatory Methane Retrievals During the Summer 2019 ACT-America Campaign"
https://doi.org/10.5194/amt-15-4623-2022
"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
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Ph.D. Dissertation Location
View from the NASA DC8 over the Atlantic Ocean during the NASA CPEX-AW 2021 campaign.