Physical and optical properties of the Pinatubo volcanic aerosol: Aircraft observations with impactors and a Sun‐tracking photometer

Pueschel, R. F.; Russell, Philip B.; Allen, D. A.; Ferry, G. V.; Snetsinger, K. G.; Livingston, J. M.; Verma, Sunita

doi:10.1029/94jd00621

Cited by 127 publications

(119 citation statements)

References 11 publications

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“…Although volcanic aerosol is often best described by multi-modal size distributions (e.g. Pueschel et al, 1994), we restricted the simulations to a single mode with a width of 1.6 for simplicity. The median radius and the number concentration were varied to cover a wide range for each particle type.…”

Section: Simulation Setupmentioning

confidence: 99%

“…In Table 5 the largest possible range is highlighted. Pueschel et al (1994) reported a single aerosol particle mode around 0.1 µm in the UTLS region for background conditions. After volcanic eruptions, they found a second, larger mode around 0.4 µm due to enhanced sulfate aerosol and a third mode around 0.8 µm containing volcanic ash particles.…”

Section: Sulfate Aerosol Simulationsmentioning

confidence: 99%

“…After volcanic eruptions, they found a second, larger mode around 0.4 µm due to enhanced sulfate aerosol and a third mode around 0.8 µm containing volcanic ash particles. Within a few days after volcanic eruptions gaseous SO 2 condenses at the volcanic ash particle's surface and forms a sulfate coating (Mossop, 1964;Farlow et al, 1981;Pueschel et al, 1994). This coating changes the complex refractive index of volcanic aerosol.…”

Section: Sulfate Aerosol Simulationsmentioning

confidence: 99%

“…The median radii (µ) of the corresponding particle size distributions are given in Table 2 together with the scattering radii (r sca ) that are weighted by the Mie scattering efficiency (Q sca ) and the effective radii (r eff ) that solely depend on the particle size distribution. Because volcanic ash size distributions have widths ranging from 1.1 to 2.2 (Farlow et al, 1981;Pueschel et al, 1994) we chose a constant width of 1.6, which is in the middle. Figure 2 shows that with increasing particle size the increase of the extinction coefficient from 825 to 950 cm −1 becomes smaller and disappears for a scattering radius of 4.9 µm.…”

Section: From Optical Properties To Infrared Limb Spectramentioning

confidence: 99%

“…Because they are efficient scatterers of ultraviolet and infrared radiation (Pueschel et al, 1994) as well as good absorbers in the infrared, they change the aerosol optical thickness in the atmosphere, affect the Earth's radiation budget, and hence have effects on climate. Volcanic eruptions can also be regarded as large atmospheric experiments, where a passive tracer, the volcanic ash, is injected from a point source.…”

Section: Introductionmentioning

confidence: 99%

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Volcanic ash detection with infrared limb sounding: MIPAS observations and radiative transfer simulations

Grießbach¹,

Hoffmann²,

Spang³

et al. 2014

Atmos. Meas. Tech.

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Abstract. Small volcanic ash particles have long residence times in the troposphere and the stratosphere so that they have significant impact on the Earth's radiative budget and consequently affect climate. For global long-term observations of volcanic aerosol, infrared limb measurements provide excellent coverage, sensitivity to thin aerosol layers, and altitude information. The optical properties of volcanic ash and ice particles, derived from micro-physical properties, have opposing spectral gradients between 700 and 960 cm −1 for small particle sizes. Radiative transfer simulations that account for single scattering showed that the opposing spectral gradients directly transfer to infrared limb spectra. Indeed, we found the characteristic spectral signature, expected for volcanic ash, in measurements of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) after the eruption of the Chilean volcano Puyehue-Cordón Caulle in June 2011. From these measurements we derived an ash detection threshold function. The empirical ash detection threshold was confirmed in an extensive simulations study covering a wide range of atmospheric conditions, particle sizes and particle concentrations for ice, volcanic ash and sulfate aerosol. From the simulations we derived the upper detectable effective radius of 3.5 µm and the detectable extinction coefficient range of 5 × 10 −3 to 1 × 10 −1 km −1 . We also showed that this method is only sensitive to volcanic ash particles, but not to volcanic sulfate aerosol. This volcanic ash detection method for infrared limb measurements is a fast and reliable method and provides complementary information to existing satellite aerosol products.

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Section: Simulation Setupmentioning

confidence: 99%

Section: Sulfate Aerosol Simulationsmentioning

confidence: 99%

Section: Sulfate Aerosol Simulationsmentioning

confidence: 99%

Section: From Optical Properties To Infrared Limb Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Volcanic ash detection with infrared limb sounding: MIPAS observations and radiative transfer simulations

Grießbach¹,

Hoffmann²,

Spang³

et al. 2014

Atmos. Meas. Tech.

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On the accuracy of stratospheric aerosol extinction derived from in situ size distribution measurements and surface area density derived from remote SAGE II and HALOE extinction measurements

Kovilakam

Deshler

2015

JGR Atmospheres

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In situ stratospheric aerosol measurements, from University of Wyoming optical particle counters (OPCs), are compared with Stratospheric Aerosol Gas Experiment (SAGE) II (versions 6.2 and 7.0) and Halogen Occultation Experiment (HALOE) satellite measurements to investigate differences between SAGE II/HALOE-measured extinction and derived surface area and OPC-derived extinction and surface area. Coincident OPC and SAGE II measurements are compared for a volcanic (1991)(1992)(1993)(1994)(1995)(1996) and nonvolcanic (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) period. OPC calculated extinctions agree with SAGE II measurements, within instrumental uncertainty, during the volcanic period, but have been a factor of 2 low during the nonvolcanic period. Three systematic errors associated with the OPC measurements, anisokineticity, inlet particle evaporation, and counting efficiency, were investigated. An overestimation of the OPC counting efficiency is found to be the major source of systematic error. With this correction OPC calculated extinction increases by 15-30% (30-50%) for the volcanic (nonvolcanic) measurements. These changes significantly improve the comparison with SAGE II and HALOE extinctions in the nonvolcanic cases but slightly degrade the agreement in the volcanic period. These corrections have impacts on OPC-derived surface area density, exacerbating the poor agreement between OPC and SAGE II (version 6.2) surface areas. This disparity is reconciled with SAGE II version 7.0 surface areas. For both the volcanic and nonvolcanic cases these changes in OPC counting efficiency and in the operational SAGE II surface area algorithm leave the derived surface areas from both platforms in significantly better agreement and within the ± 40% precision of the OPC moment calculations.

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In situ and space‐based observations of the Kelud volcanic plume: The persistence of ash in the lower stratosphere

et al. 2016

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Volcanic eruptions are important causes of natural variability in the climate system at all time scales. Assessments of the climate impact of volcanic eruptions by climate models almost universally assume that sulfate aerosol is the only radiatively active volcanic material. We report satellite observations from the Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite after the eruption of Mount Kelud (Indonesia) on 13 February 2014 of volcanic materials in the lower stratosphere. Using these observations along with in situ measurements with the Compact Optical Backscatter AerosoL Detector (COBALD) backscatter sondes and optical particle counters (OPCs) made during a balloon field campaign in northern Australia, we find that fine ash particles with a radius below 0.3 µm likely represented between 20 and 28% of the total volcanic cloud aerosol optical depth 3 months after the eruption. A separation of 1.5–2 km between the ash and sulfate plumes is observed in the CALIOP extinction profiles as well as in the aerosol number concentration measurements of the OPC after 3 months. The settling velocity of fine ash with a radius of 0.3 µm in the tropical lower stratosphere is reduced by 50% due to the upward motion of the Brewer‐Dobson circulation resulting a doubling of its lifetime. Three months after the eruption, we find a mean tropical clear‐sky radiative forcing at the top of the atmosphere from the Kelud plume near −0.08 W/m2 after including the presence of ash; a value ~20% higher than if sulfate alone is considered. Thus, surface cooling following volcanic eruptions could be affected by the persistence of ash and should be considered in climate simulations.

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Physical and optical properties of the Pinatubo volcanic aerosol: Aircraft observations with impactors and a Sun‐tracking photometer

Cited by 127 publications

References 11 publications

Volcanic ash detection with infrared limb sounding: MIPAS observations and radiative transfer simulations

Volcanic ash detection with infrared limb sounding: MIPAS observations and radiative transfer simulations

On the accuracy of stratospheric aerosol extinction derived from in situ size distribution measurements and surface area density derived from remote SAGE II and HALOE extinction measurements

In situ and space‐based observations of the Kelud volcanic plume: The persistence of ash in the lower stratosphere

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