scholarly journals Improved detection of sulphur dioxide in volcanic plumes using satellite-based hyperspectral infrared measurements: Application to the Eyjafjallajökull 2010 eruption

2012 ◽  
Vol 117 (D20) ◽  
Author(s):  
J. C. Walker ◽  
E. Carboni ◽  
A. Dudhia ◽  
R. G. Grainger
Keyword(s):  
Sulphur Dioxide ◽  
Volcanic Plumes ◽  
Infrared Measurements

scholarly journals Retrieval of sulphur dioxide from the infrared atmospheric sounding interferometer (IASI)

2011 ◽  
Vol 4 (6) ◽  
pp. 7241-7275 ◽  
Author(s):  
L. Clarisse ◽  
D. Hurtmans ◽  
C. Clerbaux ◽  
J. Hadji-Lazaro ◽  
Y. Ngadi ◽  
...  
Keyword(s):  
High Resolution ◽  
Error Analysis ◽  
Sulphur Dioxide ◽  
Weather Forecasting ◽  
Absorption Bands ◽  
Volcanic Plumes ◽  
Atmospheric Sounding ◽  
Valuable Complement ◽  
Total Column ◽  
Novel Algorithm

Abstract. Thermal infrared sounding of sulphur dioxide (SO2) from space has gained appreciation and popularity as a valuable complement to ultraviolet sounding. There are several strong absorption bands of SO2 in the infrared, and atmospheric sounders, primarily designed for weather forecasting, have therefore often the ability to globally monitor SO2 abundances. Most of the observed SO2 is found in volcanic plumes. In this paper we outline a novel algorithm for the sounding of SO2 above ~500 hPa altitude using high resolution infrared sounders and apply it to measurements of the infrared atmospheric sounding interferometer (IASI). The main features of the algorithm are a wide applicable total column range (over 4 orders of magnitude, from 0.5 to 5000 dobson units), a low theoretical uncertainty (3–5%) and near real time applicability. We make an error analysis and demonstrate the algorithm on the recent eruptions of Sarychev, Kasatochi, Grimsvötn, Puyehue-Cordón Caulle and Nabro.

scholarly journals Retrieval of the Eyjafjallajökull volcanic aerosol optical and microphysical properties from POLDER/PARASOL measurements

2014 ◽  
Vol 14 (4) ◽  
pp. 1755-1768 ◽  
Author(s):  
F. Waquet ◽  
F. Peers ◽  
P. Goloub ◽  
F. Ducos ◽  
F. Thieuleux ◽  
...  
Keyword(s):  
Single Scattering ◽  
Volcanic Plume ◽  
Volcanic Plumes ◽  
Cloud Parameters ◽  
The North ◽  
Microphysical Properties ◽  
Coarse Mode ◽  
Infrared Measurements ◽  
The North Sea ◽  
Fine Mode

Abstract. Total and polarized radiances provided by the Polarization and Directionality of Earth Reflectances (POLDER) satellite sensor are used to retrieve the microphysical and optical properties of the volcanic plume observed during the Eyjafjallajökull volcano eruption in 2010, over cloud-free and cloudy ocean scenes. We selected two plume conditions, fresh aerosols near the sources (three cases) and a downwind volcanic plume observed over the North Sea 30 h after its injection into the atmosphere (aged aerosols). In the near-source conditions, the aerosol properties depend on the distance to the plume. Within the near-source plume, aerosols are mainly non-spherical and in the coarse mode with an effective radius equal to 1.75 (±0.25) μm and an Ångström exponent (AE) close to 0.0. Far from the plume, in addition to the coarse mode, there are particles retrieved in the accumulation mode, suggesting a mixture of sulfate aerosols and volcanic dust, resulting in an AE around 0.8. The properties of the aerosols also depend on whether the plume is fresh or aged. For the downwind (aged) plume, if non-spherical coarse particles as well as some fine mode particles are retrieved, the AE is higher, around ~0.4. In addition, rather low values for the real part of the refractive index (RR) were retrieved for the fresh plume (1.38 < RR < 1.48). Single scattering albedo (SSA) values ranging between 0.92 and 0.98 were retrieved over some parts of the near-source plume; despite the low accuracy of our retrievals, the derived SSA values suggest that the ash particles are rather absorbing. To consider the particle shape, a combination of spheroid models was used. Although the employed model enabled accurate modeling of the POLDER signal in the case of non-spherical ash, our approach failed to model the signal over the optically thickest parts of the near-source plume. The most probable reason for this is the presence of ice crystals within the plume. For the aerosol above clouds (AAC) scenes, polarized measurements allowed the retrieval of the optical thickness (OT) and the AE of optically thin volcanic ash. We found that all the cloud parameters retrieved by passive sensors were biased due to the presence of the elevated volcanic plumes. Finally, thermal infrared measurements were used to identify the type of multilayer scene (cirrus clouds or volcanic dust above liquid clouds) and the retrieval method also provided the OT of thin cirrus layers above the clouds near Iceland.

scholarly journals Retrieval of sulphur dioxide from the infrared atmospheric sounding interferometer (IASI)

2012 ◽  
Vol 5 (3) ◽  
pp. 581-594 ◽  
Author(s):  
L. Clarisse ◽  
D. Hurtmans ◽  
C. Clerbaux ◽  
J. Hadji-Lazaro ◽  
Y. Ngadi ◽  
...  
Keyword(s):  
High Resolution ◽  
Error Analysis ◽  
Sulphur Dioxide ◽  
Absorption Bands ◽  
Atmospheric Infrared Sounder ◽  
Volcanic Plumes ◽  
Atmospheric Sounding ◽  
Valuable Complement ◽  
Total Column ◽  
Novel Algorithm

Abstract. Thermal infrared sounding of sulphur dioxide (SO2) from space has gained appreciation as a valuable complement to ultraviolet sounding. There are several strong absorption bands of SO2 in the infrared, and atmospheric sounders, such as AIRS (Atmospheric Infrared Sounder), TES (Tropospheric Emission Spectrometer) and IASI (Infrared Atmospheric Sounding Interferometer) have the ability to globally monitor SO2 abundances. Most of the observed SO2 is found in volcanic plumes. In this paper we outline a novel algorithm for the sounding of SO2 above ~5 km altitude using high resolution infrared sounders and apply it to measurements of IASI. The main features of the algorithm are a wide applicable total column range (over 4 orders of magnitude, from 0.5 to 5000 dobson units), a low theoretical uncertainty (3–5%) and near real time applicability. We make an error analysis and demonstrate the algorithm on the recent eruptions of Sarychev, Kasatochi, Grimsvötn, Puyehue-Cordón Caulle and Nabro.

scholarly journals Retrieval of the Eyjafjallajökull volcanic aerosol optical and microphysical properties from POLDER/PARASOL measurements

2013 ◽  
Vol 13 (4) ◽  
pp. 8663-8699
Author(s):  
F. Waquet ◽  
F. Peers ◽  
P. Goloub ◽  
F. Ducos ◽  
F. Thieuleux ◽  
...  
Keyword(s):  
Single Scattering ◽  
Volcanic Plume ◽  
Volcanic Plumes ◽  
Cloud Parameters ◽  
The North ◽  
Microphysical Properties ◽  
Coarse Mode ◽  
Infrared Measurements ◽  
The North Sea ◽  
Fine Mode

Abstract. Total and polarized radiances provided by the Polarization and Directionality of Earth Reflectances (POLDER) satellite sensor are used to retrieve the microphysical and optical properties of the volcanic plume observed during the Eyjafjallajökull volcano eruption in 2010, over cloud-free and cloudy ocean scenes. We selected two plume conditions, fresh aerosols near the sources (three cases) and a downwind volcanic plume observed over the North Sea 30 h after its injection into the atmosphere (aged aerosols). In the near-source conditions, the aerosol properties depend on the distance to the plume. Within the plume, aerosols are mainly non-spherical and in the coarse mode with an effective radius equal to 1.50 (± 0.15) μm and an Ångström Exponent (AE) close to 0.0. Far from the plume, in addition to the coarse mode, there are smaller particles retrieved in the accumulation mode suggesting a mixture of sulfate aerosols and volcanic dust, resulting in an AE around 0.8. The properties of the aerosols also depend on whether the plume is fresh or aged. For the downwind (aged) plume, if non-spherical coarse particles as well as some fine mode particles are still retrieved, the AE is smaller, around ~ 0.4. In addition, the real refractive index (RR) values are larger for the downwind plume (1.42 < RR < 1.58) than for the near-source plume (1.38 < RR < 1.48). The mean Single Scattering Albedo (SSA) retrieved at 0.865 μm was estimated at 0.97 over some parts of the downwind and near-source plumes; despite the low accuracy of our retrievals, the derived SSA values suggest that the ash particles are rather absorbing. To consider the particle shape, a combination of spheroid models is used. Although the employed model enabled accurate modeling of the POLDER signal in case of non-spherical ash, our approach failed to model the signal over the optically thickest parts of the near-source plume. The most probable reason for this is speculated to be the presence of ice crystals within the plume. For the Aerosol Above Clouds (AAC) scenes, polarized measurements allowed the retrieval of the Optical Thickness (OT) and the AE of optically thin volcanic ash. We found that all the cloud parameters retrieved by passive sensors were biased due to the presence of the elevated volcanic plumes. Finally, thermal infrared measurements were used to identify the type of multi-layer scene (i.e. cirrus clouds or volcanic dust above liquid clouds) and the retrieval method also provided the OT of thin cirrus layers above the clouds near Iceland.

scholarly journals Monitoring and forecasting Etna volcanic plumes

2009 ◽  
Vol 9 (5) ◽  
pp. 1573-1585 ◽  
Author(s):  
S. Scollo ◽  
M. Prestifilippo ◽  
G. Spata ◽  
M. D'Agostino ◽  
M. Coltelli
Keyword(s):  
Volcanic Ash ◽  
Weather Forecast ◽  
Hazard Maps ◽  
Volcanic Plumes ◽  
Infrared Imager ◽  
Infrared Measurements ◽  
Forecast Data ◽  
Thermal Cameras ◽  
Monitoring And Forecasting ◽  
Ash Dispersal

Abstract. In this paper we describe the results of a project ongoing at the Istituto Nazionale di Geofisica e Vulcanologia (INGV). The objective is to develop and implement a system for monitoring and forecasting volcanic plumes of Etna. Monitoring is based at present by multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite, visual and thermal cameras, and three radar disdrometers able to detect ash dispersal and fallout. Forecasting is performed by using automatic procedures for: i) downloading weather forecast data from meteorological mesoscale models; ii) running models of tephra dispersal, iii) plotting hazard maps of volcanic ash dispersal and deposition for certain scenarios and, iv) publishing the results on a web-site dedicated to the Italian Civil Protection. Simulations are based on eruptive scenarios obtained by analysing field data collected after the end of recent Etna eruptions. Forecasting is, hence, supported by plume observations carried out by the monitoring system. The system was tested on some explosive events occurred during 2006 and 2007 successfully. The potentiality use of monitoring and forecasting Etna volcanic plumes, in a way to prevent threats to aviation from volcanic ash, is finally discussed.

scholarly journals Investigation of several proxies to estimate sulfuric acid concentration in volcanic plume conditions

2020 ◽  
Author(s):  
Clémence Rose ◽  
Matti P. Rissanen ◽  
Siddharth Iyer ◽  
Jonathan Duplissy ◽  
Chao Yan ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Sulphur Dioxide ◽  
Global Radiation ◽  
Sulfuric Acid Concentration ◽  
Predictive Ability ◽  
Volcanic Plume ◽  
Equal Weight ◽  
Airborne Measurements ◽  
Volcanic Plumes ◽  
Sink Term

Abstract. Sulfuric acid (H2SO4) is commonly accepted as a key precursor for atmospheric new particle formation (NPF). However, direct measurements of [H2SO4] remain challenging, thus preventing the determination of this important quantity, and, consequently, a complete understanding of its contribution to the NPF process. Several proxies have been developed to bridge the gaps, but their ability to predict [H2SO4] in very specific conditions such as those encountered in volcanic plumes (including in particular high sulphur dioxide mixing ratios) has not been evaluated so far. In this context, the main objective of the present study was to develop new proxies for daytime [H2SO4] in volcanic plume conditions and compare their performance to that of the proxies available in the literature. In specific, the data collected at Maïdo during the OCTAVE 2018 campaign, in the volcanic eruption plume of the Piton de la Fournaise, were first used to derive seven proxies based on the knowledge of sulphur dioxide (SO2) mixing ratio, global radiation, condensation sink (CS) and relative humidity (RH). In three of the seven proxies (F1–F3), all variables were given equal weight in the prediction of [H2SO4], while adjusted powers were allowed for the different variables in the other four proxies (A1–A4). Proxies A1–A4 were overall found to perform better compared to F1–F3, with, in specific, improved predictive ability for [H2SO4] > 2 × 108 cm−3. The CS was observed to play an important role in regulating [H2SO4], while, in contrast, the inclusion of RH did not improve the predictions. A last expression accounting for an additional sink term related to cluster formation, S1, was also tested and showed a very good predictive ability over the whole range of measured [H2SO4]. The newly developed proxies were in a second step further evaluated using airborne measurements performed in the passive degassing plume of Etna during the STRAP 2016 campaign. Increased correlations between observed and predicted [H2SO4] were obtained when the dependence of predicted [H2SO4] over CS was the lowest, and when the dependence over [SO2] was concurrently the highest. The best predictions were finally retrieved by the simple formulation of F2 (in which [SO2] and radiation alone were assumed to explain the variations of [H2SO4] with equal contributions), with a pre factor adapted to the STRAP data. All in all, our results illustrate the fairly good capacity of the proxy available in the literature to describe [H2SO4] in volcanic plume conditions, but highlight at the same time the benefit of the newly developed proxies for the prediction of the highest concentrations ([H2SO4] > 2–3 × 108 cm−3). Also, the contrasting behaviours of the new proxies in the two investigated datasets indicate that in volcanic plumes like in other environments, the relevance of a proxy can be affected by changes in environmental conditions, and that location specific coefficients do logically improve the predictions.

Infrared measurements of droplets in the dense region of diesel fuel sprays

1997 ◽  
Author(s):  
Terry Parker ◽  
Luca Rainaldi ◽  
Eric Jepsen ◽  
Terry Parker ◽  
Luca Rainaldi ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Dense Region ◽  
Fuel Sprays ◽  
Infrared Measurements
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