ESTIMATING SURFACE ELEVATION BIASES FROM SUBSURFACE SCATTERED PHOTONS FOR LASER ALTIMETERS
Three decades of satellite observations have revealed rapid changes in Earth’s cryosphere associated with anthropogenic climate change, including decreased extent and volume of Arctic sea ice, mass loss from the Greenland Ice Sheet, mass loss in West Antarctica and the Antarctic Peninsula, and incre...
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Online Access: | http://hdl.handle.net/1903/20770 https://doi.org/10.13016/M29W0927D |
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ftunivmaryland:oai:drum.lib.umd.edu:1903/20770 2023-05-15T13:47:07+02:00 ESTIMATING SURFACE ELEVATION BIASES FROM SUBSURFACE SCATTERED PHOTONS FOR LASER ALTIMETERS Greeley, Adam Paul Carton, James Digital Repository at the University of Maryland University of Maryland (College Park, Md.) Atmospheric and Oceanic Sciences 2017 application/pdf http://hdl.handle.net/1903/20770 https://doi.org/10.13016/M29W0927D en eng doi:10.13016/M29W0927D http://hdl.handle.net/1903/20770 Remote sensing cryosphere laser altimetry Dissertation 2017 ftunivmaryland https://doi.org/10.13016/M29W0927D 2022-11-11T11:11:00Z Three decades of satellite observations have revealed rapid changes in Earth’s cryosphere associated with anthropogenic climate change, including decreased extent and volume of Arctic sea ice, mass loss from the Greenland Ice Sheet, mass loss in West Antarctica and the Antarctic Peninsula, and increased outlet glacier discharge in Greenland and Antarctica. NASA’s ICESat-2 mission will continue observing these rapid changes by measuring individual photons’ round-trip travel times from the satellite to Earth’s surface, providing precise estimates of surface elevation, and subsequent mass change for ice sheets and sea ice freeboard in Earth’s polar regions. This study investigates the potential bias in ICESat-2 surface elevation estimates from photons that have volume scattered in snow by: (1) measuring the transmission of green light through snow, (2) developing a method capable of characterizing the effects of volume scattered photons recorded by laser altimeters, (3) applying this method to laboratory measurements of volume scattered photons using the simulation laser altimeter for ICESat-2, and (4) simulating volume scattered photon rage biases using a photon tracking Monte Carlo model. Transmission measurements show that green light attenuates by one order of magnitude every centimeter in the first four centimeters of snow, suggesting that detecting volume scattered photons originating from laser altimeters is unlikely after photons travel more than a few centimeters in snow. Laboratory measurements using ICESat-2’s simulation laser altimeter MABEL (Multiple Altimeter Beam Experimental Lidar), show volume scattered photon return biases of 5 – 10 cm. However, these laboratory measurements revealed a previously unidentified drift in MABEL’s ranging on the order of 5 cm, potentially overestimating the volume scattering bias. Simulations from a single-photon tracking Monte Carlo model developed for this study reveal that approximately 95% of backscattered photons accrue path lengths less than 5 cm. This suggests ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Antarctic Peninsula Antarctica Arctic Climate change glacier Greenland Ice Sheet Sea ice West Antarctica University of Maryland: Digital Repository (DRUM) Antarctic Antarctic Peninsula Arctic Greenland Mabel ENVELOPE(-44.683,-44.683,-60.667,-60.667) The Antarctic West Antarctica |
institution |
Open Polar |
collection |
University of Maryland: Digital Repository (DRUM) |
op_collection_id |
ftunivmaryland |
language |
English |
topic |
Remote sensing cryosphere laser altimetry |
spellingShingle |
Remote sensing cryosphere laser altimetry Greeley, Adam Paul ESTIMATING SURFACE ELEVATION BIASES FROM SUBSURFACE SCATTERED PHOTONS FOR LASER ALTIMETERS |
topic_facet |
Remote sensing cryosphere laser altimetry |
description |
Three decades of satellite observations have revealed rapid changes in Earth’s cryosphere associated with anthropogenic climate change, including decreased extent and volume of Arctic sea ice, mass loss from the Greenland Ice Sheet, mass loss in West Antarctica and the Antarctic Peninsula, and increased outlet glacier discharge in Greenland and Antarctica. NASA’s ICESat-2 mission will continue observing these rapid changes by measuring individual photons’ round-trip travel times from the satellite to Earth’s surface, providing precise estimates of surface elevation, and subsequent mass change for ice sheets and sea ice freeboard in Earth’s polar regions. This study investigates the potential bias in ICESat-2 surface elevation estimates from photons that have volume scattered in snow by: (1) measuring the transmission of green light through snow, (2) developing a method capable of characterizing the effects of volume scattered photons recorded by laser altimeters, (3) applying this method to laboratory measurements of volume scattered photons using the simulation laser altimeter for ICESat-2, and (4) simulating volume scattered photon rage biases using a photon tracking Monte Carlo model. Transmission measurements show that green light attenuates by one order of magnitude every centimeter in the first four centimeters of snow, suggesting that detecting volume scattered photons originating from laser altimeters is unlikely after photons travel more than a few centimeters in snow. Laboratory measurements using ICESat-2’s simulation laser altimeter MABEL (Multiple Altimeter Beam Experimental Lidar), show volume scattered photon return biases of 5 – 10 cm. However, these laboratory measurements revealed a previously unidentified drift in MABEL’s ranging on the order of 5 cm, potentially overestimating the volume scattering bias. Simulations from a single-photon tracking Monte Carlo model developed for this study reveal that approximately 95% of backscattered photons accrue path lengths less than 5 cm. This suggests ... |
author2 |
Carton, James Digital Repository at the University of Maryland University of Maryland (College Park, Md.) Atmospheric and Oceanic Sciences |
format |
Doctoral or Postdoctoral Thesis |
author |
Greeley, Adam Paul |
author_facet |
Greeley, Adam Paul |
author_sort |
Greeley, Adam Paul |
title |
ESTIMATING SURFACE ELEVATION BIASES FROM SUBSURFACE SCATTERED PHOTONS FOR LASER ALTIMETERS |
title_short |
ESTIMATING SURFACE ELEVATION BIASES FROM SUBSURFACE SCATTERED PHOTONS FOR LASER ALTIMETERS |
title_full |
ESTIMATING SURFACE ELEVATION BIASES FROM SUBSURFACE SCATTERED PHOTONS FOR LASER ALTIMETERS |
title_fullStr |
ESTIMATING SURFACE ELEVATION BIASES FROM SUBSURFACE SCATTERED PHOTONS FOR LASER ALTIMETERS |
title_full_unstemmed |
ESTIMATING SURFACE ELEVATION BIASES FROM SUBSURFACE SCATTERED PHOTONS FOR LASER ALTIMETERS |
title_sort |
estimating surface elevation biases from subsurface scattered photons for laser altimeters |
publishDate |
2017 |
url |
http://hdl.handle.net/1903/20770 https://doi.org/10.13016/M29W0927D |
long_lat |
ENVELOPE(-44.683,-44.683,-60.667,-60.667) |
geographic |
Antarctic Antarctic Peninsula Arctic Greenland Mabel The Antarctic West Antarctica |
geographic_facet |
Antarctic Antarctic Peninsula Arctic Greenland Mabel The Antarctic West Antarctica |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Arctic Climate change glacier Greenland Ice Sheet Sea ice West Antarctica |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Arctic Climate change glacier Greenland Ice Sheet Sea ice West Antarctica |
op_relation |
doi:10.13016/M29W0927D http://hdl.handle.net/1903/20770 |
op_doi |
https://doi.org/10.13016/M29W0927D |
_version_ |
1766246391179378688 |