scholarly journals SO<sub>2</sub> Layer Height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM

2019 ◽  
Author(s):  
Pascal Hedelt ◽  
Dmitry S. Efremenko ◽  
Diego G. Loyola ◽  
Robert Spurr ◽  
Lieven Clarisse
Keyword(s):  
Accurate Determination ◽  
Volcanic Eruptions ◽  
Critical Parameters ◽  
Retrieval Algorithm ◽  
Layer Height ◽  
Precise Knowledge ◽  
Learning Machine ◽  
The Impact ◽  
First Time

Abstract. Precise knowledge of the location and height of the volcanic SO2 plumes is essential for accurate determination of SO2 emitted by volcanic eruptions for aviation control applications, but so far very time-consuming to retrieve from UV satellite data. The SO2 height is furthermore one of the most critical parameters that determine the impact on the climate. We have developed an extremely fast yet accurate SO2 layer height retrieval algorithm using the Full-Physics Inverse Learning Machine (FP_ILM) algorithm, which, for the first time, is applied to TROPOMI aboard Sentinel-5 Precursor. In this work we demonstrate the ability of the FP_ILM algorithm to retrieve layer heights in near-real time applications with an accuracy of better than 2 km for SO2 total columns larger than 20 DU and show SO2 layer height results for selected volcanic eruptions.

scholarly journals Sulfur dioxide layer height retrieval from Sentinel-5 Precursor/TROPOMI using FP_ILM

2019 ◽  
Vol 12 (10) ◽  
pp. 5503-5517 ◽  
Author(s):  
Pascal Hedelt ◽  
Dmitry S. Efremenko ◽  
Diego G. Loyola ◽  
Robert Spurr ◽  
Lieven Clarisse
Keyword(s):  
Sulfur Dioxide ◽  
Accurate Determination ◽  
Volcanic Eruptions ◽  
Critical Parameters ◽  
Layer Height ◽  
Learning Machine ◽  
The Impact ◽  
First Time ◽  
Better Than

Abstract. The accurate determination of the location, height, and loading of sulfur dioxide (SO2) plumes emitted by volcanic eruptions is essential for aviation safety. The SO2 layer height is also one of the most critical parameters with respect to determining the impact on the climate. Retrievals of SO2 plume height have been carried out using satellite UV backscatter measurements, but, until now, such algorithms are very time-consuming. We have developed an extremely fast yet accurate SO2 layer height retrieval using the Full-Physics Inverse Learning Machine (FP_ILM) algorithm. This is the first time the algorithm has been applied to measurements from the TROPOMI instrument onboard the Sentinel-5 Precursor platform. In this paper, we demonstrate the ability of the FP_ILM algorithm to retrieve SO2 plume layer heights in near-real-time applications with an accuracy of better than 2 km for SO2 total columns larger than 20 DU. We present SO2 layer height results for the volcanic eruptions of Sinabung in February 2018, Sierra Negra in June 2018, and Raikoke in June 2019, observed by TROPOMI.

Extremely fast retrieval of volcanic SO2 layer heights from UV satellite data using inverse learning machines

2021 ◽  
Author(s):  
Pascal Hedelt ◽  
MariLiza Koukouli ◽  
Konstantinos Michaelidis ◽  
Taylor Isabelle ◽  
Dimitris Balis ◽  
...  
Keyword(s):  
Real Time ◽  
Accurate Determination ◽  
Principal Component ◽  
Volcanic Eruptions ◽  
Neural Network Approach ◽  
Layer Height ◽  
Precise Knowledge ◽  
Innovation Project ◽  
Learning Machine

&lt;p&gt;Precise knowledge of the location and height of the volcanic sulfur dioxide (SO&lt;sub&gt;2&lt;/sub&gt;) plume is essential for accurate determination of SO&lt;sub&gt;2&lt;/sub&gt; emitted by volcanic eruptions, however so far not available in operational near-real time UV satellite retrievals. The FP_ILM algorithm (Full-Physics Inverse Learning Machine) enables for the first time to extract the SO&lt;sub&gt;2&lt;/sub&gt; layer height information in a matter of seconds for current UV satellites and is thus applicable in NRT environments.&lt;/p&gt;&lt;p&gt;The FP_ILM combines a principal component analysis (PCA) and a neural network approach (NN) to extract the information about the volcanic SO&lt;sub&gt;2&lt;/sub&gt; layer height from high-resolution UV satellite backscatter measurements. So far, UV based SO&lt;sub&gt;2 &lt;/sub&gt;layer height retrieval algorithms were very time-consuming and therefore not suitable for near-real-time applications like aviation control, although the SO&lt;sub&gt;2&lt;/sub&gt; LH is essential for accurate determination of SO&lt;sub&gt;2&lt;/sub&gt; emitted by volcanic eruptions.&lt;/p&gt;&lt;p&gt;In this presentation, we will present the latest FP_ILM algorithm improvements and show results of recent volcanic eruptions.&lt;/p&gt;&lt;p&gt;The SO&lt;sub&gt;2&lt;/sub&gt; layer height product for Sentinel-5p/TROPOMI is developed in the framework of the SO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;Layer Height (S5P+I: SO&lt;sub&gt;2&lt;/sub&gt; LH)&amp;#160;project, which is part of ESA Sentinel-5p+ Innovation project (S5P+I). The S5P+I project aims to develop novel scientific and operational products to exploit the potential of the S5P/TROPOMI capabilities. The S5P+I: SO&lt;sub&gt;2&lt;/sub&gt; LH&amp;#160;project is dedicated to the generation of an SO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;LH product and its extensive verification with collocated ground- and space-born measurements.&lt;/p&gt;

FP_ILM: Extremely fast volcanic SO2 plume height retrieval based on S5P/TROPOMI data using inverse learning machines

2020 ◽  
Author(s):  
Dmitry Efremenko ◽  
Pascal Hedelt ◽  
Diego Loyola ◽  
Robert Spurr
Keyword(s):  
Accurate Determination ◽  
Volcanic Eruptions ◽  
Plume Height ◽  
Neural Network Approach ◽  
Layer Height ◽  
Learning Machines ◽  
Novel Method ◽  
Learning Machine ◽  
First Time

&lt;p&gt;We present here a novel method for the precise and extremely fast retrieval of volcanic SO2 layer height (LH) based on S5P/TROPOMI data. We have developed the Full-Physics Inverse Learning Machine (FP_ILM) algorithm using a combined principal components analysis (PCA) and neural network approach (NN) to extract the information about the volcanic SO2 LH from high-resolution UV backscatter measurement of TROPOMI aboard Sentinel-5 Precursor.&lt;/p&gt;&lt;p&gt;The SO2 LH is essential for accurate determination of SO2 emitted by volcanic eruptions. So far UV based SO2 plume height retrieval algorithms are very time-consuming and therefore not suitable for near-real-time applications. The FP_ILM approach however enables for the first time to extract the SO2 LH information in a matter of seconds for an entire S5P orbit and thus applicable in NRT application.&lt;/p&gt;&lt;p&gt;The FP_ILM SO2 LH product is developed as part of ESA&amp;#8217;s &amp;#8216;Sentinel-5p+ Innovation - SO2 Layer Height project&amp;#8217; (S5P+I: SO2 LH) project, dedicated to the generation of an SO2 LH product and its extensive verification with collocated ground- and space-born measurements.&lt;/p&gt;

Extremely fast retrieval of volcanic SO2 layer heights from UV satellite data using inverse learning machines

2020 ◽  
Author(s):  
Pascal Hedelt ◽  
MariLiza Koukouli ◽  
Isabelle Taylor ◽  
Dimitris Balis ◽  
Don Grainger ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Volcanic Eruption ◽  
Accurate Determination ◽  
Volcanic Eruptions ◽  
Learning Machines ◽  
Precise Knowledge ◽  
First Results ◽  
Gas Measurements ◽  
Learning Machine ◽  
Atmospheric Trace Gas

&lt;p&gt;Precise knowledge of the location and height of the volcanic sulfur dioxide (SO&lt;sub&gt;2&lt;/sub&gt;) plume is essential for accurate determination of SO&lt;sub&gt;2&lt;/sub&gt; emitted by volcanic eruptions. So far, UV based SO&lt;sub&gt;2&lt;/sub&gt; plume height retrieval algorithms are very time-consuming and therefore not suitable for near-real-time applications like aviation control. We have therefore developed the Full-Physics Inverse Learning Machine (FP_ILM) algorithm for extremely fast and accurate retrieval of volcanic SO&lt;sub&gt;2&lt;/sub&gt; layer heights based on the UV satellite instruments Sentinel-5 Precursor/TROPOMI and MetOp/GOME-2.&lt;/p&gt;&lt;p&gt;In this presentation, we will present the FP-ILM algorithm and show results of the 2019 Raikoke eruption; a strong volcanic eruption which has emitted a huge ash cloud accompanied by more than 1300 DU of SO&lt;sub&gt;2&lt;/sub&gt;, which could be detected &amp;#160;even two months after the end of eruptive event. We will also present first results of the recent Taal volcanic eruption on 13 January 2020 in Indonesia, which has injected a huge ash and SO&lt;sub&gt;2&lt;/sub&gt; plume into the upper atmosphere, with plume heights of up to 20km.&amp;#160;&lt;/p&gt;&lt;p&gt;The algorithm is developed in the framework of ESA's&amp;#160; &quot;Sentinel-5p+ Innovation: SO&lt;sub&gt;2&lt;/sub&gt; Layer Height project&quot; (S5P+I: SO2 LH),&amp;#160; dedicated to the generation of an SO&lt;sub&gt;2&lt;/sub&gt; LH product and its extensive verification with collocated ground- and space-born measurements.&lt;/p&gt;&lt;p&gt;The high-resolution UV spectrometer GOME-2 aboard the three EPS MetOp-A, -B, and &amp;#8211;C satellites perform global daily atmospheric trace-gas measurements with a spatial resolution of &amp;#160;40x40km&lt;sup&gt;2&lt;/sup&gt; at an overpass time of 8:30h local time. The UV spectrometer TROPOMI aboard the ESA Sentinel-5P satellite provides a much higher spatial resolution of currently 5.6x3.6km&lt;sup&gt;2&lt;/sup&gt; per ground pixel, at an overpass time of 13:30h. In the future, also UV instruments aboard the Sentinel-4 (geostationary) and Sentinel-5 will complement the satellite-based global monitoring of atmospheric trace gases.&lt;/p&gt;

scholarly journals Volcanic SO<sub>2</sub> Layer Height by TROPOMI/S5P; validation against IASI/MetOp and CALIOP/CALIPSO observations

2021 ◽  
Author(s):  
Maria-Elissavet Koukouli ◽  
Konstantinos Michailidis ◽  
Pascal Hedelt ◽  
Isabelle A. Taylor ◽  
Antje Inness ◽  
...  
Keyword(s):  
Real Time ◽  
Traffic Safety ◽  
European Space Agency ◽  
Volcanic Eruptions ◽  
Mean Difference ◽  
Atmospheric Composition ◽  
Retrieval Algorithm ◽  
Volcanic Plume ◽  
Layer Height ◽  
The Impact

Abstract. Volcanic eruptions eject large amounts of ash and trace gases such as sulphur dioxide (SO2) into the atmosphere. A significant difficulty in mitigating the impact of volcanic SO2 clouds on air traffic safety is that these gas emissions can be rapidly transported over long distances. The use of space-borne instruments enables the global monitoring of volcanic SO2 emissions in an economical and risk-free manner. Within the European Space Agency (ESA) Sentinel-5p+ Innovation project, the S5P SO2 Layer Height (S5P+I: SO2 LH) activities led to the improvements on the retrieval algorithm and generation of the corresponding near-real-time S5P SO2 LH products. These are currently operationally provided, in near-real-time, by the German Aerospace Center (DLR) in the framework of the Innovative Products for Analyses of Atmospheric Composition, INPULS, project. The main aim of this paper is to present its extensive verification, accomplished within the S5P+I: SO2 LH project, over major recent volcanic eruptions, against collocated space-born measurements from the IASI/Metop and CALIOP/CALIPSO instruments, as well as assess its impact on the forecasts provided by the Copernicus Atmospheric Monitoring Service, CAMS. The mean difference between S5P and IASI observations for the Raikoke 2019, the Nishinoshima 2020 and the La Soufrière-St Vincent, 2021 eruptive periods is ~0.5 ± 3 km, while for the Taal 2020 eruption, a larger difference was found, between 3 and 4 ± 3 km. The comparison of the daily mean SO2 layer heights further demonstrates the capabilities of this near-real-time product, with slopes between 0.8 and 1 and correlations ranging between 0.6 and 0.8. Comparisons between the S5P+I: SO2 LH and the CALIOP/CALIPSO ash plume height are also satisfactory at −2.5 ± 2 km, considering that the injected SO2 and ash plumes’ locations do not always coincide over an eruption. Furthermore, the CAMS assimilation of the S5P+I: SO2 LH product led to much improved model output against the non-assimilated IASI layer heights, with a mean difference of 1.5 ± 2 km compared to the original CAMS analysis, and improved the geographical spread of the Raikoke volcanic plume following the eruptive days.

scholarly journals Technical note: Boundary layer height determination from Lidar for improving air pollution episode modelling: development of new algorithm and evaluation

2017 ◽  
Author(s):  
Ting Yang ◽  
Zifa Wang ◽  
Wei Zhang ◽  
Alex Gbaguidi ◽  
Nubuo Sugimoto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
High Performance ◽  
Accurate Determination ◽  
Technical Note ◽  
Strong Increase ◽  
Layer Height ◽  
Boundary Layer Height ◽  
Retrieval Algorithms ◽  
The Impact

Abstract. Predicting air pollution events in low atmosphere over megacities requires thorough understanding of the tropospheric dynamic and chemical processes, involving notably, continuous and accurate determination of the boundary layer height (BLH). Through intensive observations experimented over Beijing (China), and an exhaustive evaluation existing algorithms applied to the BLH determination, persistent critical limitations are noticed, in particular over polluted episodes. Basically, under weak thermal convection with high aerosol loading, none of the retrieval algorithms is able to fully capture the diurnal cycle of the BLH due to pollutant insufficient vertical mixing in the boundary layer associated with the impact of gravity waves on the tropospheric structure. Subsequently, a new approach based on gravity wave theory (the cubic root gradient method: CRGM), is developed to overcome such weakness and accurately reproduce the fluctuations of the BLH under various atmospheric pollution conditions. Comprehensive evaluation of CRGM highlights its high performance in determining BLH from Lidar. In comparison with the existing retrieval algorithms, the CRGM potentially reduces related computational uncertainties and errors from BLH determination (strong increase of correlation coefficient from 0.44 to 0.91 and significant decrease of the root mean square error from 643 m to 142 m). Such newly developed technique is undoubtedly expected to contribute to improve the accuracy of air quality modelling and forecasting systems.

Reconnaissance 3-D Seismic as a Modern Exploration Tool

1988 ◽  
Vol 6 (2) ◽  
pp. 118-125
Author(s):  
D.J. Norris
Keyword(s):  
Data Quality ◽  
Accurate Determination ◽  
Considerable Improvement ◽  
Critical Parameters ◽  
Near Surface ◽  
Line Spacing ◽  
Line Separation ◽  
Exploration Tool ◽  
Reliable Interpretation

TCPL has recently carried out ‘reconnaissance or exploration’ 3-D surveys, in three different blocks, each designed to solve a different type of problem. In each case a considerable improvement in data quality and the resulting structural/stratigraphic interpretation was achieved. The Kupe South structure is a wrench-induced feature cross-cut by numerous small-medium faults. Stratigraphic changes across the prospect produce a variable quality seismic event at the top reservoir level. The Pataka Prospect comprises a narrow horst block trend within the Oakura fault zone, offshore New Plymouth. Accurate determination of potential reserves required a reliable interpretation of the fault configuration, and the amount of displacement of the reservoir horizon by the critical faults. The Waitara Prospect is affected by a ‘no-data’ zone possibly associated with volcanics in the near surface. It was necessary to define the extent and nature of the no-data zone and to calculate the effect of the interpreted volcanics on the time structure map. Prior to the surveys we modelled the effects of such critical parameters as sail-line separation, final interpolation spacing and the dimensions of the 3-D grids using existing 2-D data. Good results were obtained with a wider line spacing than is strictly required for true 3-D. Whilst the Reconnaissance 3-D method has not removed all of the difficulties with interpretation, a considerable improvement was obtained in data quality and ease of interpretation.

Castaing’s Electron Microprobe and Its Impact on Materials Science

2001 ◽  
Vol 7 (2) ◽  
pp. 178-192 ◽  
Author(s):  
Dale E. Newbury
Keyword(s):  
Electron Microprobe ◽  
Materials Science ◽  
Critical Time ◽  
Materials Engineering ◽  
Macro Scale ◽  
Materials Science And Engineering ◽  
Basic Infrastructure ◽  
The Impact ◽  
First Time

Abstract The development of the electron microprobe by Raymond Castaing provided a great stimulus to materials science at a critical time in its history. For the first time, accurate elemental analysis could be performed with a spatial resolution of 1 µm, well within the dimensions of many microstructural features. The impact of the microprobe occurred across the entire spectrum of materials science and engineering. Contributions to the basic infrastructure of materials science included more accurate and efficient determination of phase diagrams and diffusion coefficients. The study of the microstructure of alloys was greatly enhanced by electron microprobe characterization of major, minor, and trace phases, including contamination. Finally, the electron microprobe has proven to be a critical tool for materials engineering, particularly to study failures, which often begin on a micro-scale and then propagate to the macro-scale with catastrophic results.

scholarly journals The Impact of the Quality of Tap Water and the Properties of Installation Materials on the Formation of Biofilms

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1903 ◽  
Author(s):  
Dorota Papciak ◽  
Barbara Tchórzewska-Cieślak ◽  
Andżelika Domoń ◽  
Anna Wojtuś ◽  
Jakub Żywiec ◽  
...  
Keyword(s):  
Tap Water ◽  
Galvanized Steel ◽  
Phosphorus Compounds ◽  
Plate Count ◽  
Nickel Steel ◽  
Quantitative Analyses ◽  
The Impact ◽  
First Time

The article presents changes in the quality of tap water depending on time spent in installation and its impact on the creation of biofilms on various materials (polyethylene (PE), polyvinyl chloride (PVC), chrome-nickel steel and galvanized steel). For the first time, quantitative analyses of biofilm were performed using methods such as: Adenosine 5’-triphosphate (ATP) measurement, flow cytometry, heterotrophic plate count and using fractographical parameters. In the water, after leaving the experimental installation, the increase of turbidity, content of organic compounds, nitrites and nitrates was found, as well as the decrease in the content of chlorine compounds, dissolved oxygen and phosphorus compounds. There was an increase in the number of mesophilic and psychrophilic bacteria. In addition, the presence of Escherichia coli was also found. The analysis of the quantitative determination of microorganisms in a biofilm indicates that galvanized steel is the most susceptible material for the adhesion of microorganisms. These results were also confirmed by the analysis of the biofilm morphology. The roughness profile, the thickness of the biofilm layer can be estimated at about 300 μm on galvanized steel.

scholarly journals Simulating pollutant transport over complex terrain: the hydrological component

2012 ◽  
Vol 10 (4) ◽  
pp. 1223-1235 ◽  
Author(s):  
Constantina Mita ◽  
Nicolaos Catsaros
Keyword(s):  
Channel Flow ◽  
Accurate Determination ◽  
Ground Surface ◽  
Pollutant Transport ◽  
Surface Flow ◽  
Valuable Insight ◽  
Distributed Hydrological Model ◽  
Channel Network ◽  
The Impact

AbstractThe accurate determination of surface water flow pathways is of primary importance when assessing the impact of pollutant transport and watershed physical characteristics on overland and channel water quality. The mathematical description of hydrological processes over natural watersheds, requires a detailed representation of the topography, on which the accurate determination of overland and channel flow trajectories often poses difficulties. The hydrological component of the DELTA code aims to provide valuable insight into this direction by using the semi-irregular triangulated (semi-TIN) topography model DELTA/HYDRO for establishing surface flow paths that can represent reliably the natural characteristics of a watershed, addressing several major physical hydrodynamic processes. The validity of the generated paths is tested via the integration of a conventional distributed hydrological model by routing excess rainfall over ground surface and through a channel network to the watershed outlet, for a series of storm episodes on a small, but relatively complex watershed. The encouraging results obtained demonstrate the promising application potential of the model, which can be additionally complemented with a pollutant transport component to address the interactions of soluble chemicals between soil surface and overland/channel flow, in the context of a fully integrated model.

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