scholarly journals Sulfur dioxide emissions from Papandayan and Bromo, two Indonesian volcanoes

2013 ◽  
Vol 13 (10) ◽  
pp. 2399-2407 ◽  
Author(s):  
P. Bani ◽  
M. Hendrasto ◽  
H. Gunawan ◽  
S. Primulyana ◽  
Keyword(s):  
Optical Absorption Spectroscopy ◽  
Fumarolic Activity ◽  
Emission Rates ◽  
Volcanic Emissions ◽  
So2 Emission ◽  
Sulfur Dioxide Emissions ◽  
Indonesian Archipelago ◽  
So2 Flux ◽  
Flux Measurements ◽  
Active Volcanoes

Abstract. Indonesia hosts 79 active volcanoes, representing 14% of all active volcanoes worldwide. However, little is known about their SO2 contribution into the atmosphere, due to isolation and access difficulties. Existing SO2 emission budgets for the Indonesian archipelago are based on extrapolations and inferences as there is a considerable lack of field assessments of degassing. Here, we present the first SO2 flux measurements using differential optical absorption spectroscopy (DOAS) for Papandayan and Bromo, two of the most active volcanoes in Indonesia. Results indicate mean SO2 emission rates of 1.4 t d−1 from the fumarolic activity of Papandayan and more than 22–32 t d−1 of SO2 released by Bromo during a declining eruptive phase. These DOAS results are very encouraging and pave the way for a better evaluation of Indonesian volcanic emissions.

scholarly journals Sulfur dioxide emissions from Papandayan and Bromo, two Indonesian volcanoes

2013 ◽  
Vol 1 (3) ◽  
pp. 1895-1912
Author(s):  
P. Bani ◽  
M. Hendrasto ◽  
H. Gunawan ◽  
S. Primulyana ◽  
Keyword(s):  
Sulfur Dioxide ◽  
Fumarolic Activity ◽  
Emission Rates ◽  
So2 Emission ◽  
Sulfur Dioxide Emissions ◽  
Indonesian Archipelago ◽  
So2 Flux ◽  
Flux Measurements ◽  
Active Volcanoes

Abstract. Indonesia hosts 79 active volcanoes, representing 14% of all active volcanoes worldwide. However, little is known about their passive degassing into the atmosphere due to isolation and access difficulties. Existing SO2 emission budgets for the Indonesian archipelago are based on extrapolations and inferences as there is a considerable lack of field assessments of degassing. Here, we present the first SO2 flux measurements using DOAS for Papandayan and Bromo, two of the most active volcanoes in Indonesia. Results indicate mean SO2 emission rates of 1.4 t d−1 from the fumarolic activity of Papandayan and more than 22–32 t d−1 of SO2 released by Bromo during a declining eruptive phase.

scholarly journals iFit: An intensity based retrieval for volcanic SO<sub>2</sub> from scattered sunlight UV spectra

2018 ◽  
Author(s):  
Ben Esse ◽  
Mike Burton ◽  
Matthew Varnam ◽  
Ryunosuke Kazahaya ◽  
Giuseppe Salerno
Keyword(s):  
Column Density ◽  
Uv Spectra ◽  
Optical Absorption Spectroscopy ◽  
Test Cases ◽  
Reference Spectrum ◽  
Monitoring Networks ◽  
Measured Intensity ◽  
So2 Flux ◽  
Flux Measurements ◽  
Novel Method

Abstract. Accurate quantification of the sulphur dioxide (SO2) flux from volcanoes provides both an insight into magmatic processes and a powerful monitoring tool for hazard mitigation, with miniature ultraviolet spectrometers becoming the go-to method for SO2 flux measurements globally. The most common analysis method for these spectrometers is Differential Optical Absorption Spectroscopy (DOAS), in which a reference spectrum taken outside the plume is used to quantify the SO2 column density inside the plume. This can lead to problems if the reference spectrum is contaminated with SO2 as this leads to systematic underestimates in the retrieved SO2 column density. We present a novel method, named “iFit”, which retrieves the SO2 column density from UV spectra by directly fitting the measured intensity spectrum using a high resolution solar reference spectrum. This has a number of advantages over the traditional DOAS method, primarily by eliminating the requirement for a measured reference spectrum. We show that iFit can accurately retrieve SO2 column densities in a series of test cases, finding excellent agreement with existing methods without the use of a reference spectrum. We propose that iFit is well suited to application to both traverse measurements and permanent scanning stations, and shows strong potential for integration into volcano monitoring networks at observatories.

scholarly journals Retrieval of absolute SO<sub>2</sub> column amounts from scattered-light spectra: implications for the evaluation of data from automated DOAS networks

2016 ◽  
Vol 9 (12) ◽  
pp. 5677-5698 ◽  
Author(s):  
Peter Lübcke ◽  
Johannes Lampel ◽  
Santiago Arellano ◽  
Nicole Bobrowski ◽  
Florian Dinger ◽  
...  
Keyword(s):  
Scattered Light ◽  
Principal Component ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Light Sources ◽  
Reference Spectrum ◽  
Emission Rates ◽  
Instrumental Effects ◽  
So2 Emissions ◽  
So2 Emission

Abstract. Scanning spectrometer networks using scattered solar radiation in the ultraviolet spectral region have become an increasingly important tool for monitoring volcanic sulfur dioxide (SO2) emissions. Often measured spectra are evaluated using the differential optical absorption spectroscopy (DOAS) technique. In order to obtain absolute column densities (CDs), the DOAS evaluation requires a Fraunhofer reference spectrum (FRS) that is free of absorption structures of the trace gas of interest. For measurements at volcanoes such a FRS can be readily obtained if the scan (i.e. series of measurements at different elevation angles) includes viewing directions where the plume is not seen. In this case, it is possible to use these viewing directions (e.g. zenith) as FRS. Possible contaminations of the FRS by the plume can then be corrected by calculating and subtracting an SO2 offset (e.g. the lowest SO2 CD) from all viewing directions of the respective scan. This procedure is followed in the standard evaluations of data from the Network for Observation of Volcanic and Atmospheric Change (NOVAC). While this procedure is very efficient in removing Fraunhofer structures and instrumental effects it has the disadvantage that one can never be sure that there is no SO2 from the plume in the FRS. Therefore, using a modelled FRS (based on a high-resolution solar atlas) has a great advantage. We followed this approach and investigated an SO2 retrieval algorithm using a modelled FRS. In this paper, we present results from two volcanoes that are monitored by NOVAC stations and which frequently emit large volcanic plumes: Nevado del Ruiz (Colombia) recorded between January 2010 and June 2012 and from Tungurahua (Ecuador) recorded between January 2009 and December 2011. Instrumental effects were identified with help of a principal component analysis (PCA) of the residual structures of the DOAS evaluation. The SO2 retrieval performed extraordinarily well with an SO2 DOAS retrieval error of 1 − 2 × 1016 [molecules cm−2]. Compared to a standard evaluation, we found systematic differences of the differential slant column density (dSCD) of only up to  ≈ 15 % when looking at the variation of the SO2 within one scan. The major advantage of our new retrieval is that it yields absolute SO2 CDs and that it does not require complicated instrumental calibration in the field (e.g. by employing calibration cells or broadband light sources), since the method exploits the information available in the measurements.We compared our method to an evaluation that is similar to the NOVAC approach, where a spectrum that is recorded directly before the scan is used as an FRS and an SO2 CD offset is subtracted from all retrieved dSCD in the scan to correct for possible SO2 contamination of the FRS. The investigation showed that 21.4 % of the scans (containing significant amounts of SO2) at Nevado del Ruiz and 7 % of the scans at Tungurahua showed much larger SO2 CDs when evaluated using modelled FRS (more than a factor of 2). For standard evaluations the overall distribution of the SO2 CDs in a scan can in some cases indicate whether the plume affects all viewing directions and thus these scans need to be discarded for NOVAC emission rate evaluation. However, there are other cases where this is not possible and thus the reported SO2 emission rates would be underestimated. The new method can be used to identify these cases and thus it can considerably improve SO2 emission budgets.

scholarly journals On the absolute calibration of SO<sub>2</sub> cameras

2013 ◽  
Vol 6 (3) ◽  
pp. 677-696 ◽  
Author(s):  
P. Lübcke ◽  
N. Bobrowski ◽  
S. Illing ◽  
C. Kern ◽  
J. M. Alvarez Nieves ◽  
...  
Keyword(s):  
Column Density ◽  
Emission Rate ◽  
Measurement Techniques ◽  
Field Of View ◽  
Optical Absorption Spectroscopy ◽  
Absolute Calibration ◽  
Volcanic Emissions ◽  
So2 Emission ◽  
Spectral Window ◽  
Calibration Methods

Abstract. Sulphur dioxide emission rate measurements are an important tool for volcanic monitoring and eruption risk assessment. The SO2 camera technique remotely measures volcanic emissions by analysing the ultraviolet absorption of SO2 in a narrow spectral window between 300 and 320 nm using solar radiation scattered in the atmosphere. The SO2 absorption is selectively detected by mounting band-pass interference filters in front of a two-dimensional, UV-sensitive CCD detector. One important step for correct SO2 emission rate measurements that can be compared with other measurement techniques is a correct calibration. This requires conversion from the measured optical density to the desired SO2 column density (CD). The conversion factor is most commonly determined by inserting quartz cells (cuvettes) with known amounts of SO2 into the light path. Another calibration method uses an additional narrow field-of-view Differential Optical Absorption Spectroscopy system (NFOV-DOAS), which measures the column density simultaneously in a small area of the camera's field-of-view. This procedure combines the very good spatial and temporal resolution of the SO2 camera technique with the more accurate column densities obtainable from DOAS measurements. This work investigates the uncertainty of results gained through the two commonly used, but quite different, calibration methods (DOAS and calibration cells). Measurements with three different instruments, an SO2 camera, a NFOV-DOAS system and an Imaging DOAS (I-DOAS), are presented. We compare the calibration-cell approach with the calibration from the NFOV-DOAS system. The respective results are compared with measurements from an I-DOAS to verify the calibration curve over the spatial extent of the image. The results show that calibration cells, while working fine in some cases, can lead to an overestimation of the SO2 CD by up to 60% compared with CDs from the DOAS measurements. Besides these errors of calibration, radiative transfer effects (e.g. light dilution, multiple scattering) can significantly influence the results of both instrument types. The measurements presented in this work were taken at Popocatépetl, Mexico, between 1 March 2011 and 4 March 2011. Average SO2 emission rates between 4.00 and 14.34 kg s−1 were observed.

scholarly journals Continuous SO2 flux measurements for Vulcano Island, Italy

2012 ◽  
Vol 55 (2) ◽  
Author(s):  
Fabio Vita ◽  
Salvatore Inguaggiato ◽  
Nicole Bobrowski ◽  
Lorenzo Calderone ◽  
Bo Galle ◽  
...  
Keyword(s):  
Optical Absorption Spectroscopy ◽  
Volcanic System ◽  
Vulcano Island ◽  
Summit Area ◽  
So2 Flux ◽  
University Of Technology ◽  
Flux Measurements ◽  
Project Network ◽  
Closed Conduit ◽  
Aeolian Archipelago

<p>The La Fossa cone of Vulcano Island (Aeolian Archipelago, Italy) is a closed conduit volcano. Today, Vulcano Island is characterized by sulfataric activity, with a large fumarolic field that is mainly located in the summit area. A scanning differential optical absorption spectroscopy instrument designed by the Optical Sensing Group of Chalmers University of Technology in Göteborg, Sweden, was installed in the framework of the European project "Network for Observation of Volcanic and Atmospheric Change", in March 2008. This study presents the first dataset of SO<sub>2</sub> plume fluxes recorded for a closed volcanic system. Between 2008 and 2010, the SO<sub>2</sub> fluxes recorded showed average values of 12 t.d<sup>–1</sup> during the normal sulfataric activity of Vulcano Island, with one exceptional event of strong degassing that occurred between September and December, 2009, when the SO<sub>2</sub> emissions reached up to 100 t.d<sup>–1</sup>.</p>

scholarly journals The PiSpec: A Low-Cost, 3D-Printed Spectrometer for Measuring Volcanic SO2 Emission Rates

2019 ◽  
Vol 7 ◽  
Author(s):  
Thomas Charles Wilkes ◽  
Tom David Pering ◽  
Andrew John Samuel McGonigle ◽  
Jon Raffe Willmott ◽  
Robert Bryant ◽  
...  
Keyword(s):  
Low Cost ◽  
Emission Rates ◽  
So2 Emission ◽  
3D Printed

scholarly journals A rapid deployment instrument network for temporarily monitoring volcanic SO<sub>2</sub> emissions – a study case from Telica volcano

2014 ◽  
Vol 4 (1) ◽  
pp. 191-211
Author(s):  
V. Conde ◽  
D. Nilsson ◽  
B. Galle ◽  
R. Cartagena ◽  
A. Muñoz
Keyword(s):  
Measurement Techniques ◽  
Active Volcano ◽  
Optical Absorption Spectroscopy ◽  
So2 Emissions ◽  
Volcanic Gas ◽  
Data Set ◽  
So2 Flux ◽  
Geophysical Processes ◽  
Rapid Deployment ◽  
Short Time

Abstract. Volcanic gas emissions play a crucial role in describing geophysical processes; hence measurements of magmatic gases such as SO2 can be used as tracers prior and during volcanic crises. Different measurement techniques based on optical spectroscopy have provided valuable information when assessing volcanic crises. This paper describes the design and implementation of a network of spectroscopic instruments based on Differential Optical Absorption Spectroscopy (DOAS) for remote sensing of volcanic SO2 emissions, which is robust, portable and can be deployed in relative short time. The setup allows the processing of raw data in situ even in remote areas with limited accessibility, and delivers pre-processed data to end-users in near real time even during periods of volcanic crisis, via a satellite link. In addition, the hardware can be used to conduct short term studies of volcanic plumes in remotes areas. The network was tested at Telica, an active volcano located in western Nicaragua, producing what is so far the largest data set of continuous SO2 flux measurements at this volcano.

scholarly journals SO2 EMISSION MEASUREMENT BY DOAS (DIFFERENTIAL OPTICAL ABSORPTION SPECTROSCOPY) AND COSPEC (CORRELATION SPECTROSCOPY) AT MERAPI VOLCANO (INDONESIA)

2010 ◽  
Vol 8 (2) ◽  
pp. 151-157 ◽  
Author(s):  
Hanik Humaida
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Spare Part ◽  
Correlation Spectroscopy ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Emission Measurement ◽  
Gas Emission ◽  
So2 Emission ◽  
So2 Gas

The SO2 is one of the volcanic gases that can use as indicator of volcano activity. Commonly, SO2 emission is measured by COSPEC (Correlation Spectroscopy). This equipment has several disadvantages; such as heavy, big in size, difficulty in finding spare part, and expensive. DOAS (Differential Optical Absorption Spectroscopy) is a new method for SO2 emission measurement that has advantages compares to the COSPEC. Recently, this method has been developed. The SO2 gas emission measurement of Gunung Merapi by DOAS has been carried out at Kaliadem, and also by COSPEC method as comparation. The differences of the measurement result of both methods are not significant. However, the differences of minimum and maximum result of DOAS method are smaller than that of the COSPEC. It has range between 51 ton/day and 87 ton/day for DOAS and 87 ton/day and 201 ton/day for COSPEC. The measurement of SO2 gas emission evaluated with the seismicity data especially the rockfall showed the presence of the positive correlation. It may cause the gas pressure in the subsurface influencing instability of 2006 eruption lava.   Keywords: SO2 gas, Merapi, DOAS, COSPEC

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