CALIPSO Level 3 Stratospheric Aerosol Product: Version 1.00 Algorithm Description and Initial Assessment

Mapping Intimacies ◽

10.5194/amt-2019-245 ◽

2019 ◽

Author(s):

Jayanta Kar ◽

Kam-Pui Lee ◽

Mark A. Vaughan ◽

Jason L. Tackett ◽

Charles R. Trepte ◽

...

Keyword(s):

Space Station ◽

Volcanic Eruptions ◽

Satellite Observation ◽

Stratospheric Aerosol ◽

Initial Assessment ◽

Orthogonal Polarization ◽

Aerosol Layer ◽

Stratospheric Dynamics ◽

Level 3 ◽

Good Agreement

Abstract. In August 2018, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) project released a new level 3 stratospheric aerosol profile data product derived from nearly 12 years of measurements acquired by the space-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). This monthly averaged, gridded level 3 product is based on version 4.2 of the CALIOP level 1 and level 2 data products, which feature significantly improved calibration that now makes it possible to reliably retrieve profiles of stratospheric aerosol extinction and backscatter coefficients. This paper describes the science algorithm and data handling techniques that were developed to generate the CALIPSO version 1.00 level 3 stratospheric aerosol profile product. Further, we show that the retrieved extinction profiles capture the major stratospheric perturbations over the last decade resulting from volcanic eruptions, extreme smoke events, and signatures of stratospheric dynamics. Initial assessment of the product by inter-comparison with the stratospheric aerosol retrievals from the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station (ISS) indicates good agreement in the tropical stratospheric aerosol layer (30° N–30° S), where the average difference between zonal mean extinction profiles is typically less than 25 % between 20 km and 30 km. However, differences can exceed 100 % in the very low aerosol loading regimes found above 25 km at higher latitudes.

CALIPSO level 3 stratospheric aerosol profile product: version 1.00 algorithm description and initial assessment

Atmospheric Measurement Techniques ◽

10.5194/amt-12-6173-2019 ◽

2019 ◽

Vol 12 (11) ◽

pp. 6173-6191 ◽

Cited By ~ 7

Author(s):

Jayanta Kar ◽

Kam-Pui Lee ◽

Mark A. Vaughan ◽

Jason L. Tackett ◽

Charles R. Trepte ◽

...

Keyword(s):

Space Station ◽

Volcanic Eruptions ◽

Satellite Observation ◽

Stratospheric Aerosol ◽

Initial Assessment ◽

Orthogonal Polarization ◽

Aerosol Layer ◽

Stratospheric Dynamics ◽

Level 3 ◽

Lidar Ratio

Abstract. In August 2018, the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) project released a new level 3 stratospheric aerosol profile data product derived from nearly 12 years of measurements acquired by the spaceborne Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP). This monthly averaged, gridded level 3 product is based on version 4 of the CALIOP level 1B and level 2 data products, which feature significantly improved calibration that now makes it possible to reliably retrieve profiles of stratospheric aerosol extinction and backscatter coefficients at 532 nm. This paper describes the science algorithm and data handling techniques that were developed to generate the CALIPSO version 1.00 level 3 stratospheric aerosol profile product. Further, we show that the extinction profiles (retrieved using a constant lidar ratio of 50 sr) capture the major stratospheric perturbations in both hemispheres over the last decade resulting from volcanic eruptions, extreme smoke events, and signatures of stratospheric dynamics. Initial assessment of the product by intercomparison with the stratospheric aerosol retrievals from the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station (ISS) indicates good agreement in the tropical stratospheric aerosol layer (30∘ N–30∘ S), where the average difference between zonal mean extinction profiles is typically less than 25 % between 20 and 30 km (CALIPSO biased high). However, differences can exceed 100 % in the very low aerosol loading regimes found above 25 km at higher latitudes. Similarly, there are large differences (≥100 %) within 2 to 3 km above the tropopause that might be due to cloud contamination issues.

Long-term (1999–2019) variability of stratospheric aerosol over Mauna Loa, Hawaii, as seen by two co-located lidars and satellite measurements

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-6821-2020 ◽

2020 ◽

Vol 20 (11) ◽

pp. 6821-6839 ◽

Cited By ~ 1

Author(s):

Fernando Chouza ◽

Thierry Leblanc ◽

John Barnes ◽

Mark Brewer ◽

Patrick Wang ◽

...

Keyword(s):

Stratospheric Ozone ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Atmospheric Composition ◽

Orthogonal Polarization ◽

Mauna Loa ◽

Quiescent Period ◽

Level 3 ◽

The Impact ◽

Good Agreement

Abstract. As part of the Network for the Detection of Atmospheric Composition Change (NDACC), ground-based measurements obtained from the Jet Propulsion Laboratory (JPL) stratospheric ozone lidar and the NOAA stratospheric aerosol lidar at Mauna Loa, Hawaii, over the past 2 decades were used to investigate the impact of volcanic eruptions and pyrocumulonimbus (PyroCb) smoke plumes on the stratospheric aerosol load above Hawaii since 1999. Measurements at 355 and 532 nm conducted by these two lidars revealed a color ratio of 0.5 for background aerosols and small volcanic plumes and 0.8 for a PyroCb plume recorded on September 2017. Measurements of the Nabro plume by the JPL lidar in 2011–2012 showed a lidar ratio of (64±12.7) sr at 355 nm around the center of the plume. The new Global Space-based Stratospheric Aerosol Climatology (GloSSAC), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) Level 3 and Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III-ISS) stratospheric aerosol datasets were compared to the ground-based lidar datasets. The intercomparison revealed a generally good agreement, with vertical profiles of extinction coefficient within 50 % discrepancy between 17 and 23 km above sea level (a.s.l.) and 25 % above 23 km a.s.l. The stratospheric aerosol depth derived from all of these datasets shows good agreement, with the largest discrepancy (20 %) being observed between the new CALIOP Level 3 and the other datasets. All datasets consistently reveal a relatively quiescent period between 1999 and 2006, followed by an active period of multiple eruptions (e.g., Nabro) until early 2012. Another quiescent period, with slightly higher aerosol background, lasted until mid-2017, when a combination of extensive wildfires and multiple volcanic eruptions caused a significant increase in stratospheric aerosol loading. This loading maximized at the very end of the time period considered (fall 2019) as a result of the Raikoke eruption, the plume of which ascended to 26 km altitude in less than 3 months.

Retrieval of stratospheric aerosol size distribution parameters using satellite solar occultation measurements at three wavelengths

Atmospheric Measurement Techniques ◽

10.5194/amt-14-2345-2021 ◽

2021 ◽

Vol 14 (3) ◽

pp. 2345-2357

Author(s):

Felix Wrana ◽

Christian von Savigny ◽

Jacob Zalach ◽

Larry W. Thomason

Keyword(s):

Size Distribution ◽

Space Station ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Aerosol Size Distribution ◽

Aerosol Layer ◽

Data Set ◽

Extinction Coefficients ◽

Solar Occultation ◽

Spatial Coverage

Abstract. In this work, a novel approach for the determination of the particle size distribution (PSD) parameters of stratospheric sulfate aerosols is presented. For this, ratios of extinction coefficients obtained from SAGE III/ISS (Stratospheric Aerosol and Gas Experiment III on the International Space Station) solar occultation measurements at 449, 756 and 1544 nm were used to retrieve the mode width and median radius of a size distribution assumed to be monomodal lognormal. The estimated errors at the peak of the stratospheric aerosol layer, on average, lie between 20 % and 25 % for the median radius and 5 % and 7 % for the mode width. The results are consistent in magnitude with other retrieval results from the literature, but a robust comparison is difficult, mainly because of differences in temporal and spatial coverage. Other quantities like number density and effective radius were also calculated. A major advantage of the described method over other retrieval techniques is that both the median radius and the mode width can be retrieved simultaneously, without having to assume one of them. This is possible due to the broad wavelength spectrum covered by the SAGE III/ISS measurements. Also, the presented method – being based on the analysis of three wavelengths – allows unique solutions for the retrieval of PSD parameters for almost all of the observed extinction spectra, which is not the case when using only two spectral channels. In addition, the extinction coefficients from SAGE III/ISS solar occultation measurements, on which the retrieval is based, are calculated without a priori assumptions about the PSD. For those reasons, the data produced with the presented retrieval technique may be a valuable contribution for a better understanding of the variability of stratospheric aerosol size distributions, e.g. after volcanic eruptions. While this study focuses on describing the retrieval method, and a future study will discuss the PSD parameter data set produced in depth, some exemplary results for background conditions in June 2017 are shown.

Impact of the Ambae, Raikoke and Ulawun eruptions in 2018-2019 on the global stratospheric aerosol layer and climate

10.5194/egusphere-egu2020-2406 ◽

2020 ◽

Author(s):

Corinna Kloss ◽

Pasquale Sellitto ◽

Bernard Legras ◽

Jean-Paul Vernier ◽

Fabrice Jégou ◽

...

Keyword(s):

Radiative Transfer ◽

Radiative Forcing ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Orthogonal Polarization ◽

Transfer Model ◽

Aerosol Layer ◽

The Impact ◽

Aerosol Plume

Using a combination of satellite, ground-based and in-situ observations, and radiative transfer modelling, we quantify the impact of the most recent moderate volcanic eruptions (Ambae, Vanuatu in July 2018; Raikoke, Russia and Ulawun, New Guinea in June 2019) on the global stratospheric aerosol layer and climate.For the Ambae volcano (15&#176;S and 167&#176;E), we use the Stratospheric Aerosol and Gas Experiment III (SAGE III), the Ozone Mapping Profiler Suite (OMPS), the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Himawari geostationary satellite observations of the aerosol plume evolution following the Ambae eruption of July 2018. It is shown that the aerosol plume of the main eruption at Ambae in July 2018 was distributed throughout the global stratosphere within the global large-scale circulation (Brewer-Dobson circulation, BDC), to both hemispheres. Ground-based LiDAR observations in Gadanki, India, as well as in-situ Printed Optical Particle Spectrometer (POPS) measurements acquired during the BATAL campaign confirm a widespread perturbation of the stratospheric aerosol layer due to this eruption. Using the UVSPEC radiative transfer model, we also estimate the radiative forcing of this global stratospheric aerosol perturbation. The climate impact is shown to be comparable to that of the well-known and studied recent moderate stratospheric eruptions from Kasatochi (USA, 2008), Sarychev (Russia, 2009) and Nabro (Eritrea, 2011). Top of the atmosphere radiative forcing values between -0.45 and -0.60 W/m2, for the Ambae eruption of July 2018, are found.In a similar manner the dispersion of the aerosol plume of the Raikoke (48&#176;N and 153&#176;E) and Ulawun (5&#176;S and 151&#176;E) eruptions of June 2019 is analyzed. As both of those eruptions had a stratospheric impact and happened almost simultaneously, it is challenging to completely distinguish both events. Even though the eruptions occurred very recently, first results show that the aerosol plume of the Raikoke eruption resulted in an increase in aerosol extinction values, double as high as compared to that of the Ambae eruption. However, as the eruption occurred on higher latitudes, the main bulk of Raikoke aerosols was transported towards the northern higher latitude&#8217;s in the stratosphere within the BDC, as revealed by OMPS, SAGE III and a new detection algorithm for SO2 and sulfate aerosol using IASI (Infrared Atmospheric Sounder Interferometer). Even though the Raikoke eruption had a larger impact on the stratospheric aerosol layer, both events (the eruptions at Raikoke and Ambae) have to be considered in stratospheric aerosol budget and climate studies.

Cloud-Aerosol Transport System (CATS) 1064 nm calibration and validation

Atmospheric Measurement Techniques ◽

10.5194/amt-12-6241-2019 ◽

2019 ◽

Vol 12 (11) ◽

pp. 6241-6258 ◽

Cited By ~ 9

Author(s):

Rebecca M. Pauly ◽

John E. Yorks ◽

Dennis L. Hlavka ◽

Matthew J. McGill ◽

Vassilis Amiridis ◽

...

Keyword(s):

Transport System ◽

Space Station ◽

Cirrus Clouds ◽

Orthogonal Polarization ◽

Aerosol Layer ◽

Relative Uncertainty ◽

Aerosol Transport ◽

Validation Experiment ◽

Uncertainty Estimates ◽

Good Agreement

Abstract. The Cloud-Aerosol Transport System (CATS) lidar on board the International Space Station (ISS) operated from 10 February 2015 to 30 October 2017 providing range-resolved vertical backscatter profiles of Earth's atmosphere at 1064 and 532 nm. The CATS instrument design and ISS orbit lead to a higher 1064 nm signal-to-noise ratio than previous space-based lidars, allowing for direct atmospheric calibration of the 1064 nm signals. Nighttime CATS version 3-00 data were calibrated by scaling the measured data to a model of the expected atmospheric backscatter between 22 and 26 km a.m.s.l. (above mean sea level). The CATS atmospheric model is constructed using molecular backscatter profiles derived from Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis data and aerosol scattering ratios measured by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). The nighttime normalization altitude region was chosen to simultaneously minimize aerosol loading and variability within the CATS data frame, which extends from 28 to −2 km a.m.s.l. Daytime CATS version 3-00 data were calibrated through comparisons with nighttime measurements of the layer-integrated attenuated total backscatter (iATB) from strongly scattering, rapidly attenuating opaque cirrus clouds. The CATS nighttime 1064 nm attenuated total backscatter (ATB) uncertainties for clouds and aerosols are primarily related to the uncertainties in the CATS nighttime calibration technique, which are estimated to be ∼9 %. Median CATS V3-00 1064 nm ATB relative uncertainty at night within cloud and aerosol layers is 7 %, slightly lower than these calibration uncertainty estimates. CATS median daytime 1064 nm ATB relative uncertainty is 21 % in cloud and aerosol layers, similar to the estimated 16 %–18 % uncertainty in the CATS daytime cirrus cloud calibration transfer technique. Coincident daytime comparisons between CATS and the Cloud Physics Lidar (CPL) during the CATS-CALIPSO Airborne Validation Experiment (CCAVE) project show good agreement in mean ATB profiles for clear-air regions. Eight nighttime comparisons between CATS and the PollyXT ground-based lidars also show good agreement in clear-air regions between 3 and 12 km, with CATS having a mean ATB of 19.7 % lower than PollyXT. Agreement between the two instruments (∼7 %) is even better within an aerosol layer. Six-month comparisons of nighttime ATB values between CATS and CALIOP also show that iATB comparisons of opaque cirrus clouds agree to within 19 %. Overall, CATS has demonstrated that direct calibration of the 1064 nm channel is possible from a space-based lidar using the atmospheric normalization technique.

Long-term (1999–2019) variability of stratospheric aerosol over Mauna Loa, Hawaii, as seen by two co-located lidars and satellite measurements

10.5194/acp-2019-1090 ◽

2020 ◽

Author(s):

Fernando Chouza ◽

Thierry Leblanc ◽

John Barnes ◽

Mark Brewer ◽

Patrick Wang ◽

...

Keyword(s):

Stratospheric Ozone ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Atmospheric Composition ◽

Mauna Loa ◽

Quiescent Period ◽

Level 3 ◽

Ground Based Lidar ◽

The Impact ◽

Good Agreement

Abstract. As part of the Network for the Detection of Atmospheric Composition Change (NDACC), ground-based measurements obtained from the Jet Propulsion Laboratory (JPL) stratospheric ozone lidar and the NOAA stratospheric aerosol lidar at Mauna Loa, Hawaii over the past two decades were used to investigate the impact of volcanic eruptions and pyro-cumulonimbus smoke plumes on the stratospheric aerosol load above Hawaii since 1999. Measurements at 355 nm and 532 nm conducted by these two lidars revealed Ångström exponents of −1.6 for background plumes and −0.6 for a PyroCb plume recorded on September 2017. Measurements of the Nabro plume by the JPL lidar in 2011/2012 showed a lidar ratio of (64 ± 12.7) sr at 355 nm around the center of the plume. The new GloSSAC, CALIOP Level 3 and SAGE III-ISS stratospheric aerosol datasets were compared to the ground-based lidar datasets. The intercomparison revealed a generally good agreement, with vertical profiles of extinction coefficient within 50 % of discrepancy between 17 km and 23 km above sea level (ASL), and 25 % above 23 km ASL. The stratospheric aerosol depth derived from all these datasets shows good agreement, with the largest discrepancy (20 %) being observed between the new CALIOP Level 3 and the other datasets. All datasets consistently reveal a relatively quiescent period between 1999 and 2005, followed by an active period of multiple eruptions (e.g., Nabro) until early 2012. Another quiescent period, with slightly higher aerosol background, lasted until mid-2017, when a combination of extensive wildfires and multiple volcanic eruptions caused a significant increase in stratospheric aerosol loading. This loading maximized at the very end of the time period considered (fall 2019) as a result of the Raikoke eruption, the plume of which ascended to 26 km altitude in less than three months.

Five satellite sensor study of the rapid decline of wildfire smoke in the stratosphere

10.5194/acp-2021-1015 ◽

2021 ◽

Author(s):

Bengt G. Martinsson ◽

Johan Friberg ◽

Oscar S. Sandvik ◽

Moa K. Sporre

Keyword(s):

Aerosol Particles ◽

Space Station ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Vapor Concentration ◽

Orthogonal Polarization ◽

Rapid Decline ◽

Fire Event ◽

Wildfire Smoke ◽

Scattering Ratio

Abstract. Smoke from Western North American wildfires reached the stratosphere in large amounts in August 2017. Limb-oriented satellite-based sensors are commonly used for studies of wildfire aerosol injected into the stratosphere (OMPS-LP (Ozone Mapping and Profiler Suite Limb Profiler) and SAGE III/ISS (Stratospheric Aerosol and Gas Experiment III on the International Space Station)). We find that these methods are inadequate for studies the first 1–2 months after such a strong fire event due to event termination (“saturation”). The nadir-viewing lidar CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) is less affected due to shorter path in the smoke, and, further, provides means that we could use to develop a method to correct for strong attenuation of the signal. After the initial phase, the aerosol optical depth (AOD) from OMPS-LP and CALOP show very good agreement above the 380 K isentrope, whereas the OMPS-LP tends to produce higher AOD than CALIOP in the lowermost stratosphere (LMS), probably due to reduced sensitivity at altitudes below 17 km. Time series from CALIOP of attenuation-corrected stratospheric AOD of wildfire smoke show an exponential decline during the first month after the fire, which coincides with highly significant changes in the wildfire aerosol optical properties. The AOD decline is verified by the evolution of the smoke layer composition, comparing the aerosol scattering ratio (CALIOP) to the water vapor concentration from MLS (Microwave Limb Sounder). Initially the stratospheric wildfire smoke AOD is comparable with the most important volcanic eruptions during the last 25 years. Wildfire aerosol declines much faster, 80–90 % of the AOD is removed with a half-life of approximately 10 days. We hypothesize that this dramatic decline is caused by photolytic loss. This process is rarely observed in the atmosphere. However, in the stratosphere this process can be studied with practically no influence from wet deposition, in contrast to the troposphere where this is the main removal path of sub-micron aerosol particles. Despite the loss, the aerosol particles from wildfire smoke in the stratosphere are relevant for the climate.

Monitoring the Variability of the Stratospheric Aerosol Layer over Tomsk in 2016–2018 Based on Lidar Data

Meteorologiya i Gidrologiya ◽

10.52002/0130-2906-2021-1-61-72 ◽

2021 ◽

pp. 61-72

Author(s):

V. N. Marichev ◽

◽

D. A. Bochkovskiia ◽

Keyword(s):

Volcanic Eruptions ◽

Temperature Inversion ◽

Cold Season ◽

Stratospheric Aerosol ◽

Single Frequency ◽

Winter Period ◽

Lidar Data ◽

Aerosol Layer ◽

Time Data ◽

Academy Of Sciences

The results of observations of the features of intraannual variability for the vertical structure of background aerosol in the stratosphere over Western Siberia in 2016–2018 are presented and analyzed. Experimental data were obtained at the lidar complex of Zuev Institute of Atmospheric Optics (Siberian Branch, Russian Academy of Sciences) with a receiving mirror diameter of 1 m. The objective of the study is to investigate the dynamics of background stratospheric aerosol, since during this period there were no volcanic eruptions leading to the transport of eruptive aerosol into the stratosphere. The results of the study confirm a stable intraannual cycle of maximum aerosol filling of the stratosphere in winter, a decrease in spring to the minimum, practical absence in summer, and an increase in autumn. At the same time, the variability of stratification and aerosol filling is observed for different years. It was found that aerosol is concentrated in the layer up to 30 km all year round, except for the winter period. It is shown that the vertical aerosol stratification is largely determined by the thermal regime of the tropo- sphere–stratosphere boundary layer. The absence of a pronounced temperature inversion at the tropopause contributes to an increase in the stratosphere–troposphere exchange and, as a result, to the aerosol transport to the stratosphere. This situation is typical of the cold season. For the first time, data on the quantitative content of stratospheric aerosol (its mass concentration) were obtained from single- frequency lidar data.

The Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP): Experimental design and forcing input data

10.5194/gmd-2016-68 ◽

2016 ◽

Cited By ~ 2

Author(s):

Davide Zanchettin ◽

Myriam Khodri ◽

Claudia Timmreck ◽

Matthew Toohey ◽

Anja Schmidt ◽

...

Keyword(s):

Climate Models ◽

Climate Model ◽

Initial Conditions ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Aerosol Layer ◽

Model Intercomparison ◽

Climatic Response ◽

Volcanic Forcing ◽

Intercomparison Project

Abstract. The enhancement of the stratospheric aerosol layer by volcanic eruptions induces a complex set of responses causing global and regional climate effects on a broad range of timescales. Uncertainties exist regarding the climatic response to strong volcanic forcing identified in coupled climate simulations that contributed to the fifth phase of the Climate Model Intercomparison Project (CMIP5). In order to better understand the sources of these model diversities, the model intercomparison project on the climate response to volcanic forcing (VolMIP) has defined a coordinated set of idealized volcanic perturbation experiments to be carried out in alignment with the CMIP6 protocol. VolMIP provides a common stratospheric aerosol dataset for each experiment to eliminate differences in the applied volcanic forcing, and defines a set of initial conditions to determine how internal climate variability contributes to determining the response. VolMIP will assess to what extent volcanically-forced responses of the coupled ocean-atmosphere system are robustly simulated by state-of-the-art coupled climate models and identify the causes that limit robust simulated behavior, especially differences in the treatment of physical processes. This paper illustrates the design of the idealized volcanic perturbation experiments in the VolMIP protocol and describes the common aerosol forcing input datasets to be used.

Evidence for the predictability of changes in the stratospheric aerosol size following volcanic eruptions of diverse magnitudes using space-based instruments

10.5194/acp-2020-480 ◽

2020 ◽

Author(s):

Larry W. Thomason ◽

Mahesh Kovilakam ◽

Anja Schmidt ◽

Christian von Savigny ◽

Travis Knepp ◽

...

Keyword(s):

Size Distribution ◽

Extinction Coefficient ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Global Climate Models ◽

Aerosol Size Distribution ◽

Aerosol Layer ◽

Aerosol Extinction ◽

Volcanic Event ◽

Aerosol Extinction Coefficient

Abstract. An analysis of multiwavelength stratospheric aerosol extinction coefficient data from the Stratospheric Aerosol and Gas Experiment II and III/ISS instruments is used to demonstrate a coherent relationship between the perturbation in extinction coefficient in an eruption's main aerosol layer and an apparent change in aerosol size distribution that spans multiple orders of magnitude in the stratospheric impact of a volcanic event. The relationship is measurement-based and does not rely on assumptions about the aerosol size distribution. We note limitations on this analysis including that the presence of significant amounts of ash in the main aerosol layer may significantly modulate these results. Despite this limitation, these findings represent a unique opportunity to verify the performance of interactive aerosol models used in Global Climate Models and Earth System Model and may suggest an avenue for improving aerosol extinction coefficient measurements from single channel observations such the Optical Spectrograph and Infrared Imager System as they rely on a priori assumptions about particle size.