Volcanic ash detection and retrievals using SLSTR. Test case: 2019 Raikoke eruption

When an eruption event occurs it is necessary to accurately and rapidly determine the position and evolution during time of the volcanic cloud and its parameters (such as Aerosol Optical Depth-AOD, effective radius-Re and mass-Ma of the ash particles), in order to ensure the aviation security and the prompt management of the emergencies.Here we present different procedures for volcanic ash cloud detection and retrieval using S3 SLSTR (Sentinel-3 Sea and Land Surface Temperature Radiometer) data collected the 22 June at 00:07 UTC by the Sentinel-3A platform during the Raikoke (Kuril Islands) 2019 eruption.The volcanic ash detection is realized by applying an innovative machine learning based algorithm, which uses a MultiLayer Perceptron Neural Network (NN) to classify a SLSTR image in eight different surfaces/objects, distinguishing volcanic and weather clouds, and the underlying surfaces. The results obtained with the NN procedure have been compared with two consolidated approaches based on an RGB channels combination in the visible (VIS) spectral range and the Brightness Temperature Difference (BTD) procedure that exploits the thermal infrared (TIR) channels centred at 11 and 12 microns (S8 and S9 SLSTR channels respectively). The ash volcanic cloud is correctly identified by all the models and the results indicate a good agreement between the NN classification approach, the VIS-RGB and BTD procedures.The ash retrieval parameters (AOD, Re and Ma) are obtained by applying three different algorithms, all exploiting the volcanic cloud &#8220;mask&#8221; obtained from the NN detection approach. The first method is the Look Up Table (LUTp) procedure, which uses a Radiative Transfer Model (RTM) to simulate the Top Of Atmosphere (TOA) radiances in the SLSTR thermal infrared channels (S8, S9), by varying the aerosol optical depth and the effective radius. The second algorithm is the Volcanic Plume Retrieval (VPR), based on a linearization of the radiative transfer equation capable to retrieve, from multispectral satellite images, the abovementioned parameters. The third approach is a NN model, which is built on a training set composed by the inputs-outputs pairs TOA radiances vs. ash parameters. The results of the three retrieval methods have been compared, considering as reference the LUTp procedure, since that it is the most consolidated approach. The comparison shown promising agreement between the different methods, leading to the development of an integrated approach for the monitoring of volcanic ash clouds using SLSTR.The results presented in this work have been obtained in the sphere of the VISTA (Volcanic monItoring using SenTinel sensors by an integrated Approach) project, funded by ESA and developed within the EO Science for Society framework [https://eo4society.esa.int/projects/vista/].

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Simplified and Fast Atmospheric Radiative Transfer model for satellite-based aerosol optical depth retrieval

Atmospheric Environment ◽

10.1016/j.atmosenv.2020.117362 ◽

2020 ◽

Vol 224 ◽

pp. 117362 ◽

Cited By ~ 2

Author(s):

Xing Yan ◽

Nana Luo ◽

Chen Liang ◽

Zhou Zang ◽

Wenji Zhao ◽

...

Keyword(s):

Radiative Transfer ◽

Aerosol Optical Depth ◽

Optical Depth ◽

Radiative Transfer Model ◽

Transfer Model ◽

Atmospheric Radiative Transfer

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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-5145-2007 ◽

2007 ◽

Vol 7 (2) ◽

pp. 5145-5172 ◽

Cited By ~ 5

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.

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-4027-2007 ◽

2007 ◽

Vol 7 (15) ◽

pp. 4027-4042 ◽

Cited By ~ 26

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.

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Interpretation of AIRS Data in Thin Cirrus Atmospheres Based on a Fast Radiative Transfer Model

Journal of the Atmospheric Sciences ◽

10.1175/2007jas2043.1 ◽

2007 ◽

Vol 64 (11) ◽

pp. 3827-3842 ◽

Cited By ~ 21

Author(s):

Qing Yue ◽

K. N. Liou ◽

S. C. Ou ◽

B. H. Kahn ◽

P. Yang ◽

...

Keyword(s):

Radiative Transfer ◽

Data Assimilation ◽

Optical Depth ◽

Crystal Size ◽

Thermal Infrared ◽

Radiative Transfer Model ◽

Transfer Model ◽

Cirrus Cloud ◽

Ice Crystal ◽

Ice Crystal Size

Abstract A thin cirrus cloud thermal infrared radiative transfer model has been developed for application to cloudy satellite data assimilation. This radiation model was constructed by combining the Optical Path Transmittance (OPTRAN) model, developed for the speedy calculation of transmittances in clear atmospheres, and a thin cirrus cloud parameterization using a number of observed ice crystal size and shape distributions. Numerical simulations show that cirrus cloudy radiances in the 800–1130-cm−1 thermal infrared window are sufficiently sensitive to variations in cirrus optical depth and ice crystal size as well as in ice crystal shape if appropriate habit distribution models are selected a priori for analysis. The parameterization model has been applied to the Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite to interpret clear and thin cirrus spectra observed in the thermal infrared window. Five clear and 29 thin cirrus cases at nighttime over and near the Atmospheric Radiation Measurement program (ARM) tropical western Pacific (TWP) Manus Island and Nauru Island sites have been chosen for this study. A χ2-minimization program was employed to infer the cirrus optical depth and ice crystal size and shape from the observed AIRS spectra. Independent validation shows that the AIRS-inferred cloud parameters are consistent with those determined from collocated ground-based millimeter-wave cloud radar measurements. The coupled thin cirrus radiative transfer parameterization and OPTRAN, if combined with a reliable thin cirrus detection scheme, can be effectively used to enhance the AIRS data volume for data assimilation in numerical weather prediction models.

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Potential of Hyperspectral Thermal Infrared Spaceborne Measurements to Retrieve Ice Cloud Physical Properties: Case Study of IASI and IASI-NG

Remote Sensing ◽

10.3390/rs13010116 ◽

2020 ◽

Vol 13 (1) ◽

pp. 116

Author(s):

Lucie Leonarski ◽

Laurent C.-Labonnote ◽

Mathieu Compiègne ◽

Jérôme Vidot ◽

Anthony J. Baran ◽

...

Keyword(s):

Radiative Transfer ◽

Signal To Noise Ratio ◽

Thermal Infrared ◽

Radiative Transfer Model ◽

Retrieval Algorithm ◽

Transfer Model ◽

Water Path ◽

Ice Cloud ◽

Ice Water Path ◽

Ice Water

The present study aims to quantify the potential of hyperspectral thermal infrared sounders such as the Infrared Atmospheric Sounding Interferometer (IASI) and the future IASI next generation (IASI-NG) for retrieving the ice cloud layer altitude and thickness together with the ice water path. We employed the radiative transfer model Radiative Transfer for TOVS (RTTOV) to simulate cloudy radiances using parameterized ice cloud optical properties. The radiances have been computed from an ice cloud profile database coming from global operational short-range forecasts at the European Center for Medium-range Weather Forecasts (ECMWF) which encloses the normal conditions, typical variability, and extremes of the atmospheric properties over one year (Eresmaa and McNally (2014)). We performed an information content analysis based on Shannon’s formalism to determine the amount and spectral distribution of the information about ice cloud properties. Based on this analysis, a retrieval algorithm has been developed and tested on the profile database. We considered the signal-to-noise ratio of each specific instrument and the non-retrieved atmospheric and surface parameter errors. This study brings evidence that the observing system provides information on the ice water path (IWP) as well as on the layer altitude and thickness with a convergence rate up to 95% and expected errors that decrease with cloud opacity until the signal saturation is reached (satisfying retrievals are achieved for clouds whose IWP is between about 1 and 300 g/m2).

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A model sensitivity study of the impact of clouds on satellite detection and retrieval of volcanic ash

Atmospheric Measurement Techniques ◽

10.5194/amt-8-1935-2015 ◽

2015 ◽

Vol 8 (5) ◽

pp. 1935-1949 ◽

Cited By ~ 10

Author(s):

A. Kylling ◽

N. Kristiansen ◽

A. Stohl ◽

R. Buras-Schnell ◽

C. Emde ◽

...

Keyword(s):

Radiative Transfer ◽

Liquid Water ◽

Volcanic Ash ◽

Spectral Band ◽

Sensitivity Study ◽

Transfer Model ◽

Mass Loading ◽

Ice Clouds ◽

Medium Range Weather Forecast ◽

The Impact

Abstract. Volcanic ash is commonly observed by infrared detectors on board Earth-orbiting satellites. In the presence of ice and/or liquid-water clouds, the detected volcanic ash signature may be altered. In this paper the sensitivity of detection and retrieval of volcanic ash to the presence of ice and liquid-water clouds was quantified by simulating synthetic equivalents to satellite infrared images with a 3-D radiative transfer model. The sensitivity study was made for the two recent eruptions of Eyjafjallajökull (2010) and Grímsvötn (2011) using realistic water and ice clouds and volcanic ash clouds. The water and ice clouds were taken from European Centre for Medium-Range Weather Forecast (ECMWF) analysis data and the volcanic ash cloud fields from simulations by the Lagrangian particle dispersion model FLEXPART. The radiative transfer simulations were made both with and without ice and liquid-water clouds for the geometry and channels of the Spinning Enhanced Visible and Infrared Imager (SEVIRI). The synthetic SEVIRI images were used as input to standard reverse absorption ash detection and retrieval methods. Ice and liquid-water clouds were on average found to reduce the number of detected ash-affected pixels by 6–12%. However, the effect was highly variable and for individual scenes up to 40% of pixels with mass loading >0.2 g m−2 could not be detected due to the presence of water and ice clouds. For coincident pixels, i.e. pixels where ash was both present in the FLEXPART (hereafter referred to as "Flexpart") simulation and detected by the algorithm, the presence of clouds overall increased the retrieved mean mass loading for the Eyjafjallajökull (2010) eruption by about 13%, while for the Grímsvötn (2011) eruption ash-mass loadings the effect was a 4% decrease of the retrieved ash-mass loading. However, larger differences were seen between scenes (standard deviations of ±30 and ±20% for Eyjafjallajökull and Grímsvötn, respectively) and even larger ones within scenes. The impact of ice and liquid-water clouds on the detection and retrieval of volcanic ash, implies that to fully appreciate the location and amount of ash, hyperspectral and spectral band measurements by satellite instruments should be combined with ash dispersion modelling.

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Modeling the radiative effects of desert dust on weather and regional climate

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-5489-2013 ◽

2013 ◽

Vol 13 (11) ◽

pp. 5489-5504 ◽

Cited By ~ 38

Author(s):

C. Spyrou ◽

G. Kallos ◽

C. Mitsakou ◽

P. Athanasiadis ◽

C. Kalogeri ◽

...

Keyword(s):

Radiative Transfer ◽

Regional Climate ◽

Lower Troposphere ◽

Integrated Approach ◽

Dust Particles ◽

Radiative Transfer Model ◽

Limited Area ◽

Transfer Model ◽

Radiative Effects ◽

Desert Dust

Abstract. Mineral dust aerosols exert a significant effect on both solar and terrestrial radiation. By absorbing and scattering, the solar radiation aerosols reduce the amount of energy reaching the surface. In addition, aerosols enhance the greenhouse effect by absorbing and emitting outgoing longwave radiation. Desert dust forcing exhibits large regional and temporal variability due to its short lifetime and diverse optical properties, further complicating the quantification of the direct radiative effect (DRE). The complexity of the links and feedbacks of dust on radiative transfer indicate the need for an integrated approach in order to examine these impacts. In order to examine these feedbacks, the SKIRON limited area model has been upgraded to include the RRTMG (Rapid Radiative Transfer Model – GCM) radiative transfer model that takes into consideration the aerosol radiative effects. It was run for a 6 year period. Two sets of simulations were performed, one without the effects of dust and the other including the radiative feedback. The results were first evaluated using aerosol optical depth data to examine the capabilities of the system in describing the desert dust cycle. Then the aerosol feedback on radiative transfer was quantified and the links between dust and radiation were studied. The study has revealed a strong interaction between dust particles and solar and terrestrial radiation, with several implications on the energy budget of the atmosphere. A profound effect is the increased absorption (in the shortwave and longwave) in the lower troposphere and the induced modification of the atmospheric temperature profile. These feedbacks depend strongly on the spatial distribution of dust and have more profound effects where the number of particles is greater, such as near their source.

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GPU-parallel performance of the community radiative transfer model (CRTM) with the optical depth in absorber space (ODAS)-based transmittance algorithm

10.1117/12.979077 ◽

2012 ◽

Author(s):

Jarno Mielikainen ◽

Bormin Huang ◽

Hung-Lung A. Huang ◽

Tsengdar Lee

Keyword(s):

Radiative Transfer ◽

Optical Depth ◽

Radiative Transfer Model ◽

Transfer Model ◽

Parallel Performance

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Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation) at Thessaloniki, Greece

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-33265-2012 ◽

2012 ◽

Vol 12 (12) ◽

pp. 33265-33289

Author(s):

A. V. Lindfors ◽

N. Kouremeti ◽

A. Arola ◽

S. Kazadzis ◽

A. F. Bais ◽

...

Keyword(s):

Radiative Transfer ◽

Aerosol Optical Depth ◽

Optical Depth ◽

Atmospheric Aerosol ◽

Global Radiation ◽

Single Scattering ◽

Surface Radiation ◽

Surface Solar Radiation ◽

Long Time ◽

Source Of Information

Abstract. Pyranometer measurements of the solar surface radiation (SSR) are available at many locations worldwide, often as long time series covering several decades into the past. These data constitute a potential source of information on the atmospheric aerosol load. Here, we present a method for estimating the aerosol optical depth (AOD) using pyranometer measurements of the SSR together with total water vapor column information. The method, which is based on radiative transfer simulations, was developed and tested using recent data from Thessaloniki, Greece. The effective AOD calculated using this method was found to agree well with co-located AERONET measurements, exhibiting a correlation coefficient of 0.9 with 2/3 of the data found within ±20% or ±0.05 of the AERONET AOD. This is similar to the performance of current satellite aerosol methods. Differences in the AOD as compared to AERONET can be explained by variations in the aerosol properties of the atmosphere that are not accounted for in the idealized settings used in the radiative transfer simulations, such as variations in the single scattering albedo and Ångström exponent. Furthermore, the method is sensitive to calibration offsets between the radiative transfer simulations and the pyranometer SSR. The method provides an opportunity of extending our knowledge of the atmospheric aerosol load to locations and times not covered by dedicated aerosol measurements.

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