Stratospheric aerosols from the Sarychev volcano eruption in the 2009 Arctic summer

Abstract

Aerosols from the Sarychev volcano eruption (Kuril Islands, northeast of Japan) were observed in the Arctic lower stratosphere a few days after the strongest SO₂ injection which occurred on 15 and 16 June 2009. From the observations provided by the Infrared Atmospheric Sounding Interferometer (IASI) an estimated 0.9 Tg of sulphur dioxide was injected into the upper troposphere and lower stratosphere (UTLS). The resultant stratospheric sulphate aerosols were detected from satellites by the Optical Spectrograph and Infrared Imaging System (OSIRIS) limb sounder and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and from the surface by the Network for the Detection of Atmospheric Composition Changes (NDACC) lidar deployed at OHP (Observatoire de Haute-Provence, France). By the first week of July the aerosol plume had spread out over the entire Arctic region. The Sarychev-induced stratospheric aerosol over the Kiruna region (north of Sweden) was measured by the Stratospheric and Tropospheric Aerosol Counter (STAC) during eight balloon flights planned in August and September 2009. During this balloon campaign the Micro Radiomètre Ballon (MicroRADIBAL) and the Spectroscopie d'Absorption Lunaire pour l'Observation des Minoritaires Ozone et NOx (SALOMON) remote-sensing instruments also observed these aerosols. Aerosol concentrations returned to near-background levels by spring 2010. The effective radius, the surface area density (SAD), the aerosol extinction, and the total sulphur mass from STAC in situ measurements are enhanced with mean values in the range 0.15–0.21 μm, 5.5–14.7 μm² cm⁻³, 5.5–29.5 × 10⁻⁴ km⁻¹, and 4.9–12.6 × 10⁻¹⁰ kg[S] kg⁻¹[air], respectively, between 14 km and 18 km. The observed and modelled e-folding time of sulphate aerosols from the Sarychev eruption is around 70–80 days, a value much shorter than the 12–14 months calculated for aerosols from the 1991 eruption of Mt Pinatubo. The OSIRIS stratospheric aerosol optical depth (AOD) at 750 nm is enhanced by a factor of 6, with a value of 0.02 in late July compared to 0.0035 before the eruption. The HadGEM2 and MIMOSA model outputs indicate that aerosol layers in polar region up to 14–15 km are largely modulated by stratosphere–troposphere exchange processes. The spatial extent of the Sarychev plume is well represented in the HadGEM2 model with lower altitudes of the plume being controlled by upper tropospheric troughs which displace the plume downward and upper altitudes around 18–20 km, in agreement with lidar observations. Good consistency is found between the HadGEM2 sulphur mass density and the value inferred from the STAC observations, with a maximum located about 1 km above the tropopause ranging from 1 to 2 × 10⁻⁹ kg[S] kg⁻¹[air], which is one order of magnitude higher than the background level

Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in-situ and satellite observations

“…The latitudinal trend in r eff simulated by our 25 model is broadly consistent with the trend reported from ground-based remote sensing at Eureka (Nunavut, Canada) that found r eff = 0.29 µm (O'Neill et al, 2012). Modelled absolute values of r eff are also globally consistent with balloon-borne observations in August 2009 (Jégou et al, 2013). Aerosol size or r eff exerts a strong influence on SAOD (e.g.…”

“…CC BY 4.0 License. absence of nucleation of new particles in the model (Haywood et al, 2010;Jégou et al, 2013). Conversely, our study using the CESM1(WACCM) model, whose aerosol microphysics includes nucleation, finds very good agreement with OSIRIS retrievals of SAOD in terms of magnitude and temporally when the model SAOD is degraded to account for both saturation and minimum altitude limitations on the SAOD derived from OSIRIS measurements.…”

Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in situ and satellite observations

“…Measurements that locally quantified the post-eruption volcanic aerosol include groundbased remote sensing (Haywood et al, 2010;Mattis et al, 2010;Kravitz et al, 2011;O'Neill et al, 2012) and balloonborne observations. For example, Kravitz et al (2010) and Jégou et al (2013) present in situ balloon-borne observations of size-resolved stratospheric aerosol over Laramie, Wyoming, USA (June and November 2009), and Kiruna, Sweden (August-September 2009), respectively. The estimates of r eff from all these measurements range from 0.1 to 0.3 µm, i.e.…”

LOAC: a small aerosol optical counter/sizer for ground-based and balloon measurements of the size distribution and nature of atmospheric particles – Part 1: Principle of measurements and instrument evaluation

“…Aerosol particles counters are often used on the ground; some of them are used in the free atmosphere on-board aircraft or large balloons during dedicated campaigns, for example for the studies of desert dust events or volcanic aerosols (Bukowiecki et al, 2011;Jégou et al, 2013;Ryder et al, 2013) or for stratospheric studies (Rosen, 1964;Ovarlez and Ovarlez, 1995;Deshler et al, 2003;Renard et al, 2008, Renard et al, 2010b. We propose here a new optical particle counter concept called LOAC (Light Optical Aerosol Counter) that is light and compact enough to perform measurements on the ground and under all kinds of balloons in the troposphere and in the stratosphere, including meteorological balloons.…”