Quantifying gas, ash and aerosols in volcanic plumes using emission OP-FTIR measurements

2021 ◽  
Author(s):  
Jean-François Smekens ◽  
Tamsin Mather ◽  
Mike Burton
Keyword(s):  
Sulphur Dioxide ◽  
Uv Light ◽  
Volcanic Eruptions ◽  
Mitigation Strategies ◽  
Radiative Transfer Model ◽  
Volcanic Plume ◽  
Transfer Model ◽  
Ir Radiation ◽  
Time Operation ◽  
Volcano Observatories

<p>Monitoring of volcanic emissions (gas, ash and aerosols) is crucial to our understanding of eruption mechanisms, as well as to developing mitigation strategies during volcanic eruptions. Ultraviolet (UV) spectrometers and cameras are now ubiquitous monitoring tools at most volcano observatories for quantifying sulphur dioxide (SO2) emissions. However, because they rely on scattered UV light as a source of radiation, their use is limited to daytime only, and measurement windows are often further restricted by unfavourable weather conditions. On the other end of the spectrum, Open Path Fourier Transform Infrared (OP-FTIR) instruments can be used to measure the concentrations of a series of volcanic gases, and they allow for night-time operation. However, the retrieval methods rely on the presence of a strong source of IR radiation in the background - either natural (lava flow, crater rim, the sun) or artificial – restricting their use to very specific observation geometries and a narrow range of eruptive conditions. Here we present a new approach to derive quantities of SO2, ash and aerosols from measurements of a drifting volcanic plume. Using the atmosphere as a background, we measured self-emitted IR radiation from plumes at Stromboli volcano (Italy) capturing both passive degassing and ash-rich explosive plumes. We use an iterative approach with a forward radiative transfer model (the Reference Forward Model – RFM) to quantify concentrations of sulphur dioxide (SO2), aerosols and ash in the line of sight of the spectrometer. This new method could significantly enhance the scientific return from OP-FTIR instruments at volcano observatories, ultimately expanding their deployment as part of permanent scanning networks (an alternative to DOAS instruments) to provide continuous data on the emissions of gas, ash and aerosols. </p>

scholarly journals Further evidence of important environmental information content in red-to-green ratios as depicted in paintings by great masters

2014 ◽  
Vol 14 (6) ◽  
pp. 2987-3015 ◽  
Author(s):  
C. S. Zerefos ◽  
P. Tetsis ◽  
A. Kazantzidis ◽  
V. Amiridis ◽  
S. C. Zerefos ◽  
...  
Keyword(s):  
Industrial Revolution ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Radiative Transfer Model ◽  
Independent Experiment ◽  
Accurate Information ◽  
Transfer Model ◽  
Optical Extinction ◽  
The Difference ◽  
The Impact

Abstract. We examine sunsets painted by famous artists as proxy information for the aerosol optical depth after major volcanic eruptions. Images derived from precision colour protocols applied to the paintings were compared to online images, and found that the latter, previously analysed, provide accurate information. Aerosol optical depths (AODs) at 550 nm, corresponding to Northern Hemisphere middle latitudes, calculated by introducing red-to-green (R / G) ratios from a large number of paintings to a radiative transfer model, were significantly correlated with independent proxies from stratospheric AOD and optical extinction data, the dust veil index, and ice core volcanic indices. AODs calculated from paintings were grouped into 50-year intervals from 1500 to 2000. The year of each eruption and the 3 following years were defined as "volcanic". The remaining "non-volcanic" years were used to provide additional evidence of a multidecadal increase in the atmospheric optical depths during the industrial "revolution". The increase of AOD at 550 nm calculated from the paintings grows from 0.15 in the middle 19th century to about 0.20 by the end of the 20th century. To corroborate our findings, an experiment was designed in which a master painter/colourist painted successive sunsets during and after the passage of Saharan aerosols over the island of Hydra in Greece. Independent solar radiometric measurements confirmed that the master colourist's R / G ratios which were used to model his AODs, matched the AOD values measured in situ by co-located sun photometers during the declining phase of the Saharan aerosol. An independent experiment was performed to understand the difference between R / G ratios calculated from a typical volcanic aerosol and those measured from the mineral aerosol during the Hydra experiment. It was found that the differences in terms of R / G ratios were small, ranging between −2.6% and +1.6%. Also, when analysing different parts of cloudless skies of paintings following major volcanic eruptions, any structural differences seen in the paintings had not altered the results discussed above. However, a detailed study on all possible sources of uncertainties involved (such as the impact of clouds on R / G ratios) still needs to be studied. Because of the large number of paintings studied, we tentatively propose the conclusion that regardless of the school, red-to-green ratios from great masters can provide independent proxy AODs that correlate with widely accepted proxies and with independent measurements.

Impact of 3D cloud structures on tropospheric NO2 column measurements from UV-VIS sounders

2020 ◽  
Author(s):  
Huan Yu ◽  
Arve Kylling ◽  
Claudia Emde ◽  
Bernhard Mayer ◽  
Kerstin Stebel ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Mitigation Strategies ◽  
Trace Gas ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Vertical Column ◽  
Ice Clouds ◽  
Cloud Data ◽  
One Step ◽  
The Impact

<p>Operational retrievals of tropospheric trace gases from space-borne spectrometers are made using 1D radiative transfer models. To minimize cloud effects generally only partially cloudy pixels are analysed using simplified cloud contamination treatments based on radiometric cloud fraction estimates and photon path length corrections based on oxygen collision pair (O<sub>2</sub>-O<sub>2</sub>) or O<sub>2</sub>A-absorption band measurements. In reality, however, the impact of clouds can be much more complex, involving scattering of clouds in neighbouring pixels and cloud shadow effects. Therefore, to go one step further, other correction methods may be envisaged that use sub-pixel cloud information from co-located imagers. Such methods require an understanding of the impact of clouds on the real 3D radiative transfer. We quantify this impact using the MYSTIC 3D radiative transfer model. The generation of realistic 3D input cloud fields, needed by MYSTIC (or any other 3D radiative transfer model), is non-trivial. We use cloud data generated by the ICOsahedral Non-hydrostatic (ICON) atmosphere model for a region including Germany, the Netherlands and parts of other surrounding countries. The model simulates realistic liquid and ice clouds with a horizontal spatial resolution of 156 m and it has been validated against ground-based and satellite-based observational data.</p><p>As a trace gas example, we study NO<sub>2</sub>, a key tropospheric trace gas measured by the atmospheric Sentinels. The MYSTIC 3D model simulates visible spectra, which are ingested in standard DOAS retrieval algorithms to retrieve the NO<sub>2</sub> column amount. Spectra are simulated for a number of realistic cloud scenarios, snow free surface albedos, and solar and satellite geometries typical of low-earth and geostationary orbits. The retrieved NO<sub>2</sub> vertical column densities (VCD) are compared with the true values to identify conditions where 3D cloud effects lead to significant biases on the NO<sub>2</sub> VCDs. A variety of possible mitigation strategies for such pixels are then explored.</p>

scholarly journals First Comparisons of Surface Temperature Estimations between ECOSTRESS, ASTER and Landsat 8 over Italian Volcanic and Geothermal Areas

2020 ◽  
Vol 12 (1) ◽  
pp. 184 ◽  
Author(s):  
Malvina Silvestri ◽  
Vito Romaniello ◽  
Simon Hook ◽  
Massimo Musacchio ◽  
Sergio Teggi ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Heat Waves ◽  
Space Station ◽  
Volcanic Eruptions ◽  
Thermal Infrared ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Atmospheric Effects ◽  
Landsat 8 ◽  
Surface Temperatures

The ECO System Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) is a new space mission developed by NASA-JPL which launched on July 2018. It includes a multispectral thermal infrared radiometer that measures the radiances in five spectral channels between 8 and 12 μm. The primary goal of the mission is to study how plants use water by measuring their temperature from the vantage point of the International Space Station. However, as ECOSTRESS retrieves the surface temperature, the data can be used to measure other heat-related phenomena, such as heat waves, volcanic eruptions, and fires. We have cross-compared the temperatures obtained by ECOSTRESS, the Advanced Spaceborne Thermal Emission and Reflectance radiometer (ASTER) and the Landsat 8 Thermal InfraRed Sensor (TIRS) in areas where thermal anomalies are present. The use of ECOSTRESS for temperature analysis as well as ASTER and Landsat 8 offers the possibility of expanding the availability of satellite thermal data with very high spatial and temporal resolutions. The Temperature and Emissivity Separation (TES) algorithm was used to retrieve surface temperatures from the ECOSTRESS and ASTER data, while the single-channel algorithm was used to retrieve surface temperatures from the Landsat 8 data. Atmospheric effects in the data were removed using the moderate resolution atmospheric transmission (MODTRAN) radiative transfer model driven with vertical atmospheric profiles collected by the University of Wyoming. The test sites used in this study are the active Italian volcanoes and the Parco delle Biancane geothermal area (Italy). In order to test and quantify the difference between the temperatures retrieved by the three spaceborne sensors, a set of coincident imagery was acquired and used for cross comparison. Preliminary statistical analyses show a very good agreement in terms of correlation and mean values among sensors over the test areas.

scholarly journals Retrieval of SO<sub>2</sub> from thermal infrared satellite measurements: correction procedures for the effects of volcanic ash

2009 ◽  
Vol 2 (1) ◽  
pp. 303-342 ◽  
Author(s):  
S. Corradini ◽  
L. Merucci ◽  
A. J. Prata
Keyword(s):  
Spectral Range ◽  
Thermal Infrared ◽  
Radiative Transfer Model ◽  
Volcanic Plume ◽  
Simultaneous Estimation ◽  
Transfer Model ◽  
Correction Procedure ◽  
Absorption Bands ◽  
Data Set ◽  
Least Squares Fit

Abstract. The simultaneous presence of SO2 and ash in a volcanic plume can lead to a significant error in the SO2 columnar abundance retrieval when multispectral Thermal InfraRed (TIR) data are used. The ash particles within the plume with effective radii (from 1 to 10 μm) reduce the Top Of Atmosphere (TOA) radiance in the entire TIR spectral range, including the channels used for SO2 retrieval. The net effect is a significant SO2 overestimation. In this work the interference of ash is discussed and two correction procedures for satellite SO2 volcanic plume retrieval in the TIR spectral range are developed to achieve an higher computation speed and a better accuracy. The ash correction can be applied when the sensor spectral range includes the 7.3 and/or 8.7 μm SO2 absorption bands, and the split window bands centered around 11 and 12 μm required for ash retrieval. This allows the possibility of a simultaneous estimation of both volcanic SO2 and ash in the same data set. The proposed ash correction procedures have been applied to the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Spin Enhanced Visible and Infrared Imager (SEVIRI) measurements. Data collected during the 24 November 2006 Mt. Etna eruption have been used to illustrate the technique. The SO2 and ash estimations are carried out by using a least squares fit method and the Brightness Temperature Difference (BTD) procedures, respectively. The simulated TOA radiance Look-Up Table (LUT) needed for the SO2 columnar abundance and the ash retrievals have been computed using the MODTRAN 4 Radiative Transfer Model. The results show the importance of the ash correction on SO2 retrieval at 8.7 μm – the SO2 columnar abundance corrected by the ash influence is less than one half of the values retrieved without the correction. The ash correction on SO2 retrieval at 7.3 μm is much less important and only significant for low SO2 columnar abundances. Results also show that the simplified and faster correction procedure underestimates the ash correction compared with the more time consuming but more accurate correction procedure. Such underestimation is greater for instruments having better ground pixel resolution, i.e. greater for MODIS than for SEVIRI.

scholarly journals Atmospheric effects of volcanic eruptions as seen by famous artists and depicted in their paintings

2007 ◽  
Vol 7 (2) ◽  
pp. 5145-5172 ◽  
Author(s):  
C. S. Zerefos ◽  
V. T. Gerogiannis ◽  
D. Balis ◽  
S. C. Zerefos ◽  
A. Kazantzidis
Keyword(s):  
Time Series ◽  
Radiative Transfer ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Volcanic Eruptions ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Atmospheric Effects ◽  
Middle Latitudes ◽  
Time Period

Abstract. Paintings created by famous artists, representing sunsets throughout the period 1500–1900, provide proxy information on the aerosol optical depth following major volcanic eruptions. This is supported by a statistically significant correlation coefficient (0.8) between the measured red-to-green ratios of 327 paintings and the corresponding values of the dust veil index. A radiative transfer model was used to compile an independent time series of aerosol optical depth at 550 nm corresponding to Northern Hemisphere middle latitudes during the period 1500–1900. The estimated aerosol optical depths range from 0.05 for background aerosol conditions, to about 0.6 following the Tambora and Krakatau eruptions and cover a time period mostly outside of the instrumentation era.

scholarly journals Further evidence of important environmental information content in red-to-green ratios as depicted in paintings by great masters

2013 ◽  
Vol 13 (12) ◽  
pp. 33145-33176 ◽  
Author(s):  
C. S. Zerefos ◽  
P. Tetsis ◽  
A. Kazantzidis ◽  
V. Amiridis ◽  
S. C. Zerefos ◽  
...  
Keyword(s):  
Industrial Revolution ◽  
Volcanic Eruptions ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Extinction Data ◽  
Optical Extinction ◽  
Follow Up Study ◽  
Time Period

Abstract. This work is a follow-up study of a research carried out since 2005 and presents evidence supporting the findings of an earlier paper (Zerefos et al., 2007), which postulated that sunsets painted by famous artists provide independent proxy information on the aerosol optical depth after major volcanic eruptions. The series of these and additional paintings have been revisited and comparisons between coarser digital images with those derived from precision colour protocols, match together confirming the earlier results as discussed in the text. It was also found that aerosol optical depths (AODs) at 550 nm calculated by feeding Red-to-Green (R/G) ratios from a large number of paintings to a radiative transfer model, were well correlated with independent proxies from stratospheric AOD and optical extinction data, the dust veil index and others. AODs calculated from paintings have been grouped into 50 yr intervals from 1500 to 2000. From each 50 yr time period the year of the eruption and the 3 following years have been excluded. The remaining years have been termed "non-volcanic" and they provide additional evidence of a multidecadal increase in the atmospheric optical depths during the industrial "revolution". The increase of AOD at 550 nm calculated from the paintings, is estimated to range from 0.15 in the middle 19th century to about 0.20 by the end of the 20th century. To corroborate our findings, an experiment was designed in which a master painter/colourist painted successive sunsets during and after the passage of Saharan aerosols over the island of Hydra in Greece. Independent solar radiometric measurements confirmed that the master colourist's R/G ratios which were used to model his AODs, matched to the AOD values measured in situ by the co-located sunphotometers at the declining phase of the Sahara aerosol. Our work concludes that regardless of the school, red-to-green ratios from great masters can provide independent proxy AODs that correlate with widely accepted proxies and with independent measurements.

scholarly journals Atmospheric effects of volcanic eruptions as seen by famous artists and depicted in their paintings

2007 ◽  
Vol 7 (15) ◽  
pp. 4027-4042 ◽  
Author(s):  
C. S. Zerefos ◽  
V. T. Gerogiannis ◽  
D. Balis ◽  
S. C. Zerefos ◽  
A. Kazantzidis
Keyword(s):  
Time Series ◽  
Radiative Transfer ◽  
Correlation Coefficient ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Volcanic Eruptions ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Atmospheric Effects ◽  
Middle Latitudes

Abstract. Paintings created by famous artists, representing sunsets throughout the period 1500–1900, provide proxy information on the aerosol optical depth following major volcanic eruptions. This is supported by a statistically significant correlation coefficient (0.8) between the measured red-to-green ratios of a few hundred paintings and the dust veil index. A radiative transfer model was used to compile an independent time series of aerosol optical depth at 550 nm corresponding to Northern Hemisphere middle latitudes during the period 1500–1900. The estimated aerosol optical depths range from 0.05 for background aerosol conditions, to about 0.6 following the Tambora and Krakatau eruptions and cover a period practically outside of the instrumentation era.

Probing clouds in planets with a simple radiative transfer model: the Jupiter case

2012 ◽  
Vol 33 (6) ◽  
pp. 1611-1624 ◽  
Author(s):  
Iñigo Mendikoa ◽  
Santiago Pérez-Hoyos ◽  
Agustín Sánchez-Lavega
Keyword(s):  
Radiative Transfer ◽  
Radiative Transfer Model ◽  
Transfer Model
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