Anti‐Correlation between stratospheric aerosol extinction and the Ångström parameter from multiple wavelength measurements with SAGE II—A characteristic of the decay period following major volcanic eruptions

Hayashida, Sachiko; Horikawa, Mariko

doi:10.1029/2000gl012826

Cited by 8 publications

(6 citation statements)

References 8 publications

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“…Has background been reached? In hindsight it now seems clear, based on the volcanically quiescent period following Pinatubo, that background was not reached prior to Pinatubo [ Barnes and Hofmann , 2001; Hayashida and Horikawa , 2001], Figures 2, 3, and 4.…”

Section: Investigation Of Trends In the Long‐term Aerosol Measurementmentioning

confidence: 99%

“…Based on long‐term lidar measurements at Mauna Loa, Hawaii, Barnes and Hofmann [1997] suggest that the decay of aerosol loading following El Chichón and Pinatubo was influenced by the phase of the QBO in tropical stratospheric winds (also evident in the Garmisch lidar data [ Jäger , 2005]) and that integrated aerosol backscatter in 1995 was below any previous observation at Mauna Loa. Hayashida and Horikawa [2001] used SAGE II extinction measurements to derive Ångström parameters and concluded that the pre‐Pinatubo period was still influenced by volcanic eruptions from the mid‐1980s and cannot be considered a real background period. Barnes and Hofmann [2001] used the present background period, extending from 1996, to demonstrate variability correlated with the phase of the QBO, with implications for the source of background stratospheric aerosol.…”

Section: Introductionmentioning

confidence: 99%

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Trends in the nonvolcanic component of stratospheric aerosol over the period 1971–2004

Deshler¹,

Anderson-Sprecher²,

Jäger³

et al. 2006

J. Geophys. Res.

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[1] The six longest records of stratospheric aerosol (in situ measurements at Laramie, Wyoming, lidar records at: Garmisch-Partenkirchen, Germany; Hampton, Virginia; Mauna Loa, Hawaii; São José dos Campos, Brazil, and SAGE II measurements) were investigated for trend by (1) comparing measurements in the 3 volcanically quiescent periods since 1970 using standard analysis of variance techniques, and (2) analyzing residuals from a time/volcano dependent empirical model applied to entire data sets. A standard squared-error residual minimization technique was used to estimate optimum parameters for each measurement set, allowing for first order autocorrelation, which increases standard errors of trends but does not change magnitude. Analysis of variance over the 3 volcanically quiescent periods is controlled by the end points (pre-El Chichón and post-Pinatubo), and indicates either no change (Garmisch, Hampton, São José dos Campos, Laramie-0.15 mm) or a slight, statistically insignificant, decrease (Mauna Loa, Laramie-0.25 mm), À1 ± 0.5% yr À1 . The empirical model was applied to the same records plus 1020 nm SAGE II data separated into 33 latitude/altitude bins. No trend in stratospheric aerosol was apparent for 31 of 33 SAGE II data sets, 3 of 4 lidar records, and in situ measurements at 0.15 mm. For Hampton and Laramie-0.25 mm, the results suggest a weak negative trend, À2 ± 0.5% yr À1, while 2 SAGE II data sets (30-35 km, 30°and 40°N) suggest a positive trend of similar magnitude. Overall we conclude that no long-term change in background stratospheric aerosol has occurred over the period 1970-2004.

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Section: Investigation Of Trends In the Long‐term Aerosol Measurementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Trends in the nonvolcanic component of stratospheric aerosol over the period 1971–2004

Deshler¹,

Anderson-Sprecher²,

Jäger³

et al. 2006

J. Geophys. Res.

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“…They also presented measurements of integrated aerosol backscatter in 1995 which were below any previous observations at Mauna Loa. Another comparison of the pre‐Pinatubo and post‐Pinatubo periods was performed by Hayashida and Horikawa [2001] using SAGE II extinction measurements to derive Ångström parameters. They conclude that the pre‐Pinatubo period was still influenced by volcanic eruptions from the mid 1980s and cannot be considered a real background period.…”

Section: Introductionmentioning

confidence: 99%

Thirty years of in situ stratospheric aerosol size distribution measurements from Laramie, Wyoming (41°N), using balloon‐borne instruments

et al. 2003

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[1] Vertical profiles of size-resolved aerosol concentrations above Laramie, Wyoming (41°N), have been measured for the past thirty years, . During this period, two somewhat different optical particle counters have been used to measure particles with radii !0.15 mm, whereas the instrument to measure condensation nuclei (CN) has not changed significantly since the late 1970s. The two optical particle counters measure aerosols !0.15, 0.25 mm and aerosols !0.15-2.0 mm in twelve size classes. These measurements have concentration (N) uncertainties / ±N À0.5 , but with a minimum of ±10%. Sizing uncertainties are about ±10%. The impact of these uncertainties on size distribution fitting parameters and aerosol moments are approximately ±30% and ±40%. The long-term record from these measurements indicates that volcanoes have controlled stratospheric aerosol abundance for 20 of the past 30 years. The present period, beginning in 1997, represents the longest volcanically quiescent period in the record. These and other measurements clearly show that stratospheric aerosol are now in a background state, a state rarely occurring in recent times, and that this background state is not significantly different than observations in 1979. Aerosol volumes and surface areas, inferred from size distributions fit to the measurements, are compared with SAGE II satellite estimates of surface area and volume. For volume the measurements are in agreement within measurement error throughout the record. For surface area there is good agreement for a volcanic aerosol laden stratosphere, but for background aerosol conditions the SAGE II estimates are about 40% less than the in situ measurements. Present aerosol surface areas are $1.0 (0.6) mm 2 cm À3 in the 15-20 (20-25) km layer based on in situ measurements. The Laramie size distribution record is now available to the community over the internet. (8409); KEYWORDS: stratospheric aerosol size distributions, volcanic stratospheric aerosol, background stratospheric aerosol, in situ aerosol size distribution measurements, optical particle counters, balloonborne aerosol measurements Citation: Deshler, T., M. E. Hervig, D. J. Hofmann, J. M. Rosen, and J. B. Liley, Thirty years of in situ stratospheric aerosol size distribution measurements from Laramie, Wyoming (41°N), using balloon-borne instruments,

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“…A sensitivity analysis perturbing those two parameters within the values in the model atmospheres of Gallery et al (1983) shows that z refr typically lies between 12 and 14 km. (2) might be seen as a plausible representation of globally-averaged conditions (Hayashida & Horikawa 2001). The aerosol loading in scenario (3) is abnormally elevated for typical Earth conditions but may be representative of the atmosphere after a major volcanic eruption .…”

Section: The Earth In Transitmentioning

confidence: 99%

Glancing Views of the Earth: From a Lunar Eclipse to an Exoplanetary Transit

Muñoz

Osorio

Barrena

et al. 2012

ApJ

107

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It has been posited that lunar eclipse observations may help predict the in-transit signature of Earth-like extrasolar planets. However, a comparative analysis of the two phenomena addressing in detail the transport of stellar light through the planet's atmosphere has not yet been presented. Here, we proceed with the investigation of both phenomena by making use of a common formulation. Our starting point is a set of previously unpublished near-infrared spectra collected at various phases during the August 2008 lunar eclipse. We then take the formulation to the limit of an infinitely distant observer in order to investigate the in-transit signature of the Earth-Sun system as being observed from outside our Solar System. The refraction-bending of sunlight rays that pass through the Earth's atmosphere is a critical factor in the illumination of the eclipsed Moon. Likewise, refraction will have an impact on the in-transit transmission spectrum for specific planet-star systems depending on the refractive properties of the planet's atmosphere, the stellar size and the planet's orbital distance. For the Earth-Sun system, at mid-transit, refraction prevents the remote observer's access to the lower ∼12-14 km of the atmosphere and, thus, also to the bulk of the spectroscopically-active atmospheric gases. We demonstrate that the effective optical radius of the Earth in transit is modulated by refraction and varies by ∼12 km from mid-transit to 2nd contact. The refractive nature of atmospheres, a property which is rarely accounted for in published investigations, will pose additional challenges to the characterization of Earthlike extrasolar planets. Refraction may have a lesser impact for Earth-like extrasolar planets within the habitable zone of some M-type stars.

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Anti‐Correlation between stratospheric aerosol extinction and the Ångström parameter from multiple wavelength measurements with SAGE II—A characteristic of the decay period following major volcanic eruptions

Cited by 8 publications

References 8 publications

Trends in the nonvolcanic component of stratospheric aerosol over the period 1971–2004

Trends in the nonvolcanic component of stratospheric aerosol over the period 1971–2004

Thirty years of in situ stratospheric aerosol size distribution measurements from Laramie, Wyoming (41°N), using balloon‐borne instruments

Glancing Views of the Earth: From a Lunar Eclipse to an Exoplanetary Transit

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