Recovery of the first ever multi-year lidar dataset of the stratospheric aerosol layer, from Lexington, MA, and Fairbanks, AK, January 1964 to July 1965
<p>We report the recovery and processing methodology of the first ever multi-year lidar dataset of the stratospheric aerosol layer. A Q-switched ruby lidar measured 66 vertical profiles of 694 nm attenuated backscatter at Lexington, Massachusetts, between January 1964 and August 1965, with an...
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Copernicus Publications
2021-09-01
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| Series: | Earth System Science Data |
| Online Access: | https://essd.copernicus.org/articles/13/4407/2021/essd-13-4407-2021.pdf |
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| author | J.-C. Antuña-Marrero G. W. Mann G. W. Mann J. Barnes A. Rodríguez-Vega S. Shallcross S. S. Dhomse S. S. Dhomse G. Fiocco G. W. Grams |
| author_facet | J.-C. Antuña-Marrero G. W. Mann G. W. Mann J. Barnes A. Rodríguez-Vega S. Shallcross S. S. Dhomse S. S. Dhomse G. Fiocco G. W. Grams |
| author_sort | J.-C. Antuña-Marrero |
| collection | DOAJ |
| description | <p>We report the recovery and processing methodology of the first
ever multi-year lidar dataset of the stratospheric aerosol layer. A
Q-switched ruby lidar measured 66 vertical profiles of 694 nm attenuated
backscatter at Lexington, Massachusetts, between January 1964 and August 1965, with an additional nine profile measurements conducted from College,
Alaska, during July and August 1964. We describe the processing of the
recovered lidar backscattering ratio profiles to produce mid-visible (532 nm)
stratospheric aerosol extinction profiles (sAEP<span class="inline-formula"><sub>532</sub></span>) and stratospheric
aerosol optical depth (sAOD<span class="inline-formula"><sub>532</sub></span>) measurements, utilizing a number of
contemporary measurements of several different atmospheric variables.
Stratospheric soundings of temperature and pressure generate an accurate
local molecular backscattering profile, with nearby ozone soundings
determining the ozone absorption, which are used to correct for two-way
ozone transmittance. Two-way aerosol transmittance corrections are also
applied based on nearby observations of total aerosol optical depth (across
the troposphere and stratosphere) from sun photometer measurements. We show
that accounting for these two-way transmittance effects substantially
increases the magnitude of the 1964/1965 stratospheric aerosol layer's optical
thickness in the Northern Hemisphere mid-latitudes, then <span class="inline-formula">∼</span> 50 % larger than represented in the Coupled Model Intercomparison Project 6 (CMIP6) volcanic forcing dataset.
Compared to the uncorrected dataset, the combined transmittance correction
increases the sAOD<span class="inline-formula"><sub>532</sub></span> by up to 66 % for Lexington and up to 27 %
for Fairbanks, as well as individual sAEP<span class="inline-formula"><sub>532</sub></span> adjustments of similar magnitude.
Comparisons with the few contemporary measurements available show better
agreement with the corrected two-way transmittance values.</p>
<p>Within the January 1964 to August 1965 measurement time span, the corrected
Lexington sAOD<span class="inline-formula"><sub>532</sub></span> time series is substantially above 0.05 in three
distinct periods, October 1964, March 1965, and May–June 1965, whereas the 6 nights the lidar measured in December 1964 and January 1965 had sAOD values of at most <span class="inline-formula">∼</span> 0.03. The comparison with interactive stratospheric aerosol
model simulations of the Agung aerosol cloud shows that, although
substantial variation in mid-latitude sAOD<span class="inline-formula"><sub>532</sub></span> are expected from the
seasonal cycle in the stratospheric circulation, the Agung cloud's
dispersion from the tropics would have been at its strongest in winter and
weakest in summer. The increasing trend in sAOD from January to July 1965,
also considering the large variability,<span id="page4408"/> suggests that the observed
variations are from a different source than Agung, possibly from one or both
of the two eruptions that occurred in 1964/1965 with a Volcanic Explosivity Index (VEI) of 3: Trident, Alaska, and
Vestmannaeyjar, Heimaey, south of Iceland. A detailed error analysis of the
uncertainties in each of the variables involved in the processing chain was
conducted. Relative errors for the uncorrected sAEP<span class="inline-formula"><sub>532</sub></span> were 54 % for
Fairbanks and 44 % Lexington. For the corrected sAEP<span class="inline-formula"><sub>532</sub></span> the errors
were 61 % and 64 %, respectively. The analysis of the uncertainties
identified variables that with additional data recovery and reprocessing
could reduce these relative error levels. Data described in this work are
available at <a href="https://doi.org/10.1594/PANGAEA.922105">https://doi.org/10.1594/PANGAEA.922105</a> (Antuña-Marrero et al., 2020a).</p> |
| first_indexed | 2024-12-16T09:56:56Z |
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| id | doaj.art-2e24a03bfe084a1b8df280173dc5d968 |
| institution | Directory Open Access Journal |
| issn | 1866-3508 1866-3516 |
| language | English |
| last_indexed | 2024-12-16T09:56:56Z |
| publishDate | 2021-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth System Science Data |
| spelling | doaj.art-2e24a03bfe084a1b8df280173dc5d9682022-12-21T22:35:54ZengCopernicus PublicationsEarth System Science Data1866-35081866-35162021-09-01134407442310.5194/essd-13-4407-2021Recovery of the first ever multi-year lidar dataset of the stratospheric aerosol layer, from Lexington, MA, and Fairbanks, AK, January 1964 to July 1965J.-C. Antuña-Marrero0G. W. Mann1G. W. Mann2J. Barnes3A. Rodríguez-Vega4S. Shallcross5S. S. Dhomse6S. S. Dhomse7G. Fiocco8G. W. Grams9Group of Atmospheric Optics (GOA-UVa), Universidad de Valladolid, 47011, Valladolid, SpainSchool of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UKNational Centre for Atmospheric Science (NCAS-Climate), University of Leeds, Leeds, LS2 9JT, UKNOAA ESRL Global Monitoring Laboratory, Boulder, CO, USAGrupo de Óptica Atmosférica de Camagüey, Centro Meteorológico de Camagüey, INSMET, Camagüey, CubaSchool of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UKSchool of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UKNational Centre for Earth Observation (NCEO), University of Leeds, Leeds, LS2 9JT, UKDepartment of Geology and Geophysics and Research, Laboratory of Electronics, Massachusetts Institute of Technology, 02139, Cambridge, MA, USADepartment of Geology and Geophysics and Research, Laboratory of Electronics, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA<p>We report the recovery and processing methodology of the first ever multi-year lidar dataset of the stratospheric aerosol layer. A Q-switched ruby lidar measured 66 vertical profiles of 694 nm attenuated backscatter at Lexington, Massachusetts, between January 1964 and August 1965, with an additional nine profile measurements conducted from College, Alaska, during July and August 1964. We describe the processing of the recovered lidar backscattering ratio profiles to produce mid-visible (532 nm) stratospheric aerosol extinction profiles (sAEP<span class="inline-formula"><sub>532</sub></span>) and stratospheric aerosol optical depth (sAOD<span class="inline-formula"><sub>532</sub></span>) measurements, utilizing a number of contemporary measurements of several different atmospheric variables. Stratospheric soundings of temperature and pressure generate an accurate local molecular backscattering profile, with nearby ozone soundings determining the ozone absorption, which are used to correct for two-way ozone transmittance. Two-way aerosol transmittance corrections are also applied based on nearby observations of total aerosol optical depth (across the troposphere and stratosphere) from sun photometer measurements. We show that accounting for these two-way transmittance effects substantially increases the magnitude of the 1964/1965 stratospheric aerosol layer's optical thickness in the Northern Hemisphere mid-latitudes, then <span class="inline-formula">∼</span> 50 % larger than represented in the Coupled Model Intercomparison Project 6 (CMIP6) volcanic forcing dataset. Compared to the uncorrected dataset, the combined transmittance correction increases the sAOD<span class="inline-formula"><sub>532</sub></span> by up to 66 % for Lexington and up to 27 % for Fairbanks, as well as individual sAEP<span class="inline-formula"><sub>532</sub></span> adjustments of similar magnitude. Comparisons with the few contemporary measurements available show better agreement with the corrected two-way transmittance values.</p> <p>Within the January 1964 to August 1965 measurement time span, the corrected Lexington sAOD<span class="inline-formula"><sub>532</sub></span> time series is substantially above 0.05 in three distinct periods, October 1964, March 1965, and May–June 1965, whereas the 6 nights the lidar measured in December 1964 and January 1965 had sAOD values of at most <span class="inline-formula">∼</span> 0.03. The comparison with interactive stratospheric aerosol model simulations of the Agung aerosol cloud shows that, although substantial variation in mid-latitude sAOD<span class="inline-formula"><sub>532</sub></span> are expected from the seasonal cycle in the stratospheric circulation, the Agung cloud's dispersion from the tropics would have been at its strongest in winter and weakest in summer. The increasing trend in sAOD from January to July 1965, also considering the large variability,<span id="page4408"/> suggests that the observed variations are from a different source than Agung, possibly from one or both of the two eruptions that occurred in 1964/1965 with a Volcanic Explosivity Index (VEI) of 3: Trident, Alaska, and Vestmannaeyjar, Heimaey, south of Iceland. A detailed error analysis of the uncertainties in each of the variables involved in the processing chain was conducted. Relative errors for the uncorrected sAEP<span class="inline-formula"><sub>532</sub></span> were 54 % for Fairbanks and 44 % Lexington. For the corrected sAEP<span class="inline-formula"><sub>532</sub></span> the errors were 61 % and 64 %, respectively. The analysis of the uncertainties identified variables that with additional data recovery and reprocessing could reduce these relative error levels. Data described in this work are available at <a href="https://doi.org/10.1594/PANGAEA.922105">https://doi.org/10.1594/PANGAEA.922105</a> (Antuña-Marrero et al., 2020a).</p>https://essd.copernicus.org/articles/13/4407/2021/essd-13-4407-2021.pdf |
| spellingShingle | J.-C. Antuña-Marrero G. W. Mann G. W. Mann J. Barnes A. Rodríguez-Vega S. Shallcross S. S. Dhomse S. S. Dhomse G. Fiocco G. W. Grams Recovery of the first ever multi-year lidar dataset of the stratospheric aerosol layer, from Lexington, MA, and Fairbanks, AK, January 1964 to July 1965 Earth System Science Data |
| title | Recovery of the first ever multi-year lidar dataset of the stratospheric aerosol layer, from Lexington, MA, and Fairbanks, AK, January 1964 to July 1965 |
| title_full | Recovery of the first ever multi-year lidar dataset of the stratospheric aerosol layer, from Lexington, MA, and Fairbanks, AK, January 1964 to July 1965 |
| title_fullStr | Recovery of the first ever multi-year lidar dataset of the stratospheric aerosol layer, from Lexington, MA, and Fairbanks, AK, January 1964 to July 1965 |
| title_full_unstemmed | Recovery of the first ever multi-year lidar dataset of the stratospheric aerosol layer, from Lexington, MA, and Fairbanks, AK, January 1964 to July 1965 |
| title_short | Recovery of the first ever multi-year lidar dataset of the stratospheric aerosol layer, from Lexington, MA, and Fairbanks, AK, January 1964 to July 1965 |
| title_sort | recovery of the first ever multi year lidar dataset of the stratospheric aerosol layer from lexington ma and fairbanks ak january 1964 to july 1965 |
| url | https://essd.copernicus.org/articles/13/4407/2021/essd-13-4407-2021.pdf |
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