scholarly journals Extended observations of volcanic SO<sub>2</sub> and sulfate aerosol in the stratosphere

2007 ◽  
Vol 7 (1) ◽  
pp. 2857-2871 ◽  
Author(s):  
S. A. Carn ◽  
N. A. Krotkov ◽  
K. Yang ◽  
R. M. Hoff ◽  
A. J. Prata ◽  
...  
Keyword(s):  
Climate Change ◽  
Sulfur Dioxide ◽  
Satellite Data ◽  
Volcanic Eruptions ◽  
Sulfate Aerosol ◽  
Satellite Observations ◽  
Ozone Monitoring Instrument ◽  
Ozone Monitoring ◽  
Composition Structure ◽  
Stratospheric Composition

Abstract. Sulfate aerosol produced after injection of sulfur dioxide (SO2) into the stratosphere by volcanic eruptions can trigger climate change. We present new satellite data from the Ozone Monitoring Instrument (OMI) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) missions that reveal the composition, structure and longevity of a stratospheric SO2 cloud and derived sulfate layer following a modest eruption (0.2 Tg total SO2) of Soufriere Hills volcano, Montserrat on 20 May 2006. The SO2 cloud alone was tracked for over 3 weeks and a distance of over 20 000 km; unprecedented for an eruption of this size. Derived sulfate aerosol at an altitude of ~20 km had circled the globe by 22 June and remained visible in CALIPSO data until at least 6 July. These synergistic NASA A-Train observations permit a new appreciation of the potential effects of frequent, small-to-moderate volcanic eruptions on stratospheric composition and climate.

scholarly journals Validation of OMI, GOME-2A and GOME-2B tropospheric NO<sub>2</sub>, SO<sub>2</sub> and HCHO products using MAX-DOAS observations from 2011 to 2014 in Wuxi, China

2016 ◽  
Author(s):  
Yang Wang ◽  
Steffen Beirle ◽  
Johannes lampel ◽  
Mariliza Koukouli ◽  
Isabelle De Smedt ◽  
...  
Keyword(s):  
Satellite Data ◽  
Trace Gases ◽  
Satellite Observations ◽  
Urban Region ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Shape Factors ◽  
Weekly Cycle ◽  
Comparison Results ◽  
Ozone Monitoring

Abstract. Tropospheric vertical column densities (VCDs) of NO2, SO2 and HCHO derived from Ozone Monitoring Instrument (OMI) on AURA and Global Ozone Monitoring Experiment 2 aboard METOP-A (GOME-2A) and METOP-B (GOME-2B) are widely used to characterize the global distributions, trends, dominating sources of the trace gases and for comparisons with chemical transport models (CTM). We use tropospheric VCDs and vertical profiles of NO2, SO2 and HCHO derived from MAX-DOAS measurements from 2011 to 2014 in Wuxi, China, to validate the corresponding products derived from OMI, GOME-2A/B by different scientific teams (daily and bimonthly averaged data). Prior to the comparison we investigate the effects of the spatial and temporal coincidence criteria for MAX-DOAS and satellite data on the comparison results. We find that the distance of satellite data from the location of the MAX-DOAS station is the dominating effect, and we make suggestions for the spatial (20 km for OMI NO2 and SO2 products and 50 km for OMI HCHO and all GOME-2A/B products) and temporal averaging (2 hours around satellite overpass time). We also investigate the effect of clouds on both MAX-DOAS and satellite observations. Our results indicate that the discrepancies between satellite and MAX-DOAS results increase with increasing effective cloud fractions and are dominated by the cloud effect on the satellite products. Our comparison results indicate a systematic underestimation of all SO2 (40 % to 57 %) and HCHO products (about 20 %) and an overestimation of the GOME-2A/B NO2 products (about 30 %) (DOMINO NO2 product is only slightly underestimated by 1 %). To better understand the reasons for the differences, we recalculated the AMFs for satellite observations based on the shape factors (SFs) derived from MAX-DOAS. The recalculated satellite VCDs agree better with the MAX-DOAS VCDs than those from the original products by up to 10 %, 47 % and 35 % for NO2, SO2 and HCHO, respectively. The improvement is strongest for periods with large trace gas VCDs. Finally we investigate the effect of aerosols on the satellite retrievals. We find an increasing underestimation of the OMI NO2, SO2 and HCHO products with increasing AOD by up to 8 %, 12 % and 2 %, respectively. One reason for this finding is that aerosols systematically affect the satellite cloud retrievals and can lead to apparent effective cloud fractions of up to 10 % and apparent cloud top pressures of down to 830 hPa for the typical urban region in Wuxi. We show that in such cases the implicit aerosol correction could cause a strong underestimation of tropospheric VCDs by up to about 45 %, 77 % and 100 % for NO2, SO2 and HCHO, respectively. For such conditions it might be better to apply AMFs for clear sky conditions than AMFs based on the satellite cloud retrievals. We find that the satellites systematically overestimate the magnitude of the diurnal variations of NO2 and HCHO. No significant weekly cycle for all trace gases is found by either the satellites or the MAX-DOAS measurements.

scholarly journals Detecting volcanic sulfur dioxide plumes in the Northern Hemisphere using the Brewer spectrophotometers, other networks, and satellite observations

2017 ◽  
Vol 17 (1) ◽  
pp. 551-574 ◽  
Author(s):  
Christos S. Zerefos ◽  
Kostas Eleftheratos ◽  
John Kapsomenakis ◽  
Stavros Solomos ◽  
Antje Inness ◽  
...  
Keyword(s):  
Sulfur Dioxide ◽  
Northern Hemisphere ◽  
Theoretical Calculations ◽  
Volcanic Eruptions ◽  
Ground Level ◽  
Atmospheric Composition ◽  
Ozone Monitoring Instrument ◽  
Volcanic Origin ◽  
Local Pollution ◽  
Ozone Monitoring

Abstract. This study examines the adequacy of the existing Brewer network to supplement other networks from the ground and space to detect SO2 plumes of volcanic origin. It was found that large volcanic eruptions of the last decade in the Northern Hemisphere have a positive columnar SO2 signal seen by the Brewer instruments located under the plume. It is shown that a few days after the eruption the Brewer instrument is capable of detecting significant columnar SO2 increases, exceeding on average 2 DU relative to an unperturbed pre-volcanic 10-day baseline, with a mean close to 0 and σ = 0.46, as calculated from the 32 Brewer stations under study. Intercomparisons with independent measurements from the ground and space as well as theoretical calculations corroborate the capability of the Brewer network to detect volcanic plumes. For instance, the comparison with OMI (Ozone Monitoring Instrument) and GOME-2 (Global Ozone Monitoring Experiment-2) SO2 space-borne retrievals shows statistically significant agreement between the Brewer network data and the collocated satellite overpasses in the case of the Kasatochi eruption. Unfortunately, due to sparsity of satellite data, the significant positive departures seen in the Brewer and other ground networks following the Eyjafjallajökull, Bárðarbunga and Nabro eruptions could not be statistically confirmed by the data from satellite overpasses. A model exercise from the MACC (Monitoring Atmospheric Composition and Climate) project shows that the large increases in SO2 over Europe following the Bárðarbunga eruption in Iceland were not caused by local pollution sources or ship emissions but were clearly linked to the volcanic eruption. Sulfur dioxide positive departures in Europe following Bárðarbunga could be traced by other networks from the free troposphere down to the surface (AirBase (European air quality database) and EARLINET (European Aerosol Research Lidar Network)). We propose that by combining Brewer data with that from other networks and satellites, a useful tool aided by trajectory analyses and modelling could be created which can also be used to forecast high SO2 values both at ground level and in air flight corridors following future eruptions.

scholarly journals Opportunistic validation of sulfur dioxide in the Sarychev Peak volcanic eruption cloud

2011 ◽  
Vol 4 (9) ◽  
pp. 1705-1712 ◽  
Author(s):  
S. A. Carn ◽  
T. M. Lopez
Keyword(s):  
Sulfur Dioxide ◽  
Limited Data ◽  
Ozone Monitoring Instrument ◽  
Spatial And Temporal Scales ◽  
Eruption Cloud ◽  
Kurile Islands ◽  
Volcanic Cloud ◽  
Ozone Monitoring ◽  
Lidar Observations ◽  
Sarychev Peak

Abstract. We report attempted validation of Ozone Monitoring Instrument (OMI) sulfur dioxide (SO2) retrievals in the stratospheric volcanic cloud from Sarychev Peak (Kurile Islands) in June 2009, through opportunistic deployment of a ground-based ultraviolet (UV) spectrometer (FLYSPEC) as the volcanic cloud drifted over central Alaska. The volcanic cloud altitude (~12–14 km) was constrained using coincident CALIPSO lidar observations. By invoking some assumptions about the spatial distribution of SO2, we derive averages of FLYSPEC vertical SO2 columns for comparison with OMI SO2 measurements. Despite limited data, we find minimum OMI-FLYSPEC differences within measurement uncertainties, which support the validity of the operational OMI SO2 algorithm. However, our analysis also highlights the challenges involved in comparing datasets representing markedly different spatial and temporal scales. This effort represents the first attempt to validate SO2 in a stratospheric volcanic cloud using a mobile ground-based instrument, and demonstrates the need for a network of rapidly deployable instruments for validation of space-based volcanic SO2 measurements.

scholarly journals Long-term MAX-DOAS network observations of NO<sub>2</sub> in Russia and Asia (MADRAS) during the period 2007–2012: instrumentation, elucidation of climatology, and comparisons with OMI satellite observations and global model simulations

2014 ◽  
Vol 14 (15) ◽  
pp. 7909-7927 ◽  
Author(s):  
Y. Kanaya ◽  
H. Irie ◽  
H. Takashima ◽  
H. Iwabuchi ◽  
H. Akimoto ◽  
...  
Keyword(s):  
Satellite Data ◽  
Transport Model ◽  
Satellite Observations ◽  
Global Model ◽  
Optical Absorption Spectroscopy ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Data Set ◽  
Model Simulations

Abstract. We conducted long-term network observations using standardized Multi-Axis Differential optical absorption spectroscopy (MAX-DOAS) instruments in Russia and ASia (MADRAS) from 2007 onwards and made the first synthetic data analysis. At seven locations (Cape Hedo, Fukue and Yokosuka in Japan, Hefei in China, Gwangju in Korea, and Tomsk and Zvenigorod in Russia) with different levels of pollution, we obtained 80 927 retrievals of tropospheric NO2 vertical column density (TropoNO2VCD) and aerosol optical depth (AOD). In the technique, the optimal estimation of the TropoNO2VCD and its profile was performed using aerosol information derived from O4 absorbances simultaneously observed at 460–490 nm. This large data set was used to analyze NO2 climatology systematically, including temporal variations from the seasonal to the diurnal scale. The results were compared with Ozone Monitoring Instrument (OMI) satellite observations and global model simulations. Two NO2 retrievals of OMI satellite data (NASA ver. 2.1 and Dutch OMI NO2 (DOMINO) ver. 2.0) generally showed close correlations with those derived from MAX-DOAS observations, but had low biases of up to ~50%. The bias was distinct when NO2 was abundantly present near the surface and when the AOD was high, suggesting a possibility of incomplete accounting of NO2 near the surface under relatively high aerosol conditions for the satellite observations. Except for constant biases, the satellite observations showed nearly perfect seasonal agreement with MAX-DOAS observations, suggesting that the analysis of seasonal features of the satellite data were robust. Weekend reduction in the TropoNO2VCD found at Yokosuka and Gwangju was absent at Hefei, implying that the major sources had different weekly variation patterns. While the TropoNO2VCD generally decreased during the midday hours, it increased exceptionally at urban/suburban locations (Yokosuka, Gwangju, and Hefei) during winter. A global chemical transport model, MIROC-ESM-CHEM (Model for Interdisciplinary Research on Climate–Earth System Model–Chemistry), was validated for the first time with respect to background NO2 column densities during summer at Cape Hedo and Fukue in the clean marine atmosphere.

scholarly journals Estimating European volatile organic compound emissions using satellite observations of formaldehyde from the Ozone Monitoring Instrument

2010 ◽  
Vol 10 (23) ◽  
pp. 11501-11517 ◽  
Author(s):  
G. Curci ◽  
P. I. Palmer ◽  
T. P. Kurosu ◽  
K. Chance ◽  
G. Visconti
Keyword(s):  
Satellite Observations ◽  
Atmospheric Composition ◽  
Ozone Monitoring Instrument ◽  
Top Down ◽  
Bottom Up ◽  
Voc Emissions ◽  
The Balkans ◽  
Monitoring Instrument ◽  
Volatile Organic ◽  
Ozone Monitoring

Abstract. Emission of non-methane Volatile Organic Compounds (VOCs) to the atmosphere stems from biogenic and human activities, and their estimation is difficult because of the many and not fully understood processes involved. In order to narrow down the uncertainty related to VOC emissions, which negatively reflects on our ability to simulate the atmospheric composition, we exploit satellite observations of formaldehyde (HCHO), an ubiquitous oxidation product of most VOCs, focusing on Europe. HCHO column observations from the Ozone Monitoring Instrument (OMI) reveal a marked seasonal cycle with a summer maximum and winter minimum. In summer, the oxidation of methane and other long-lived VOCs supply a slowly varying background HCHO column, while HCHO variability is dominated by most reactive VOC, primarily biogenic isoprene followed in importance by biogenic terpenes and anthropogenic VOCs. The chemistry-transport model CHIMERE qualitatively reproduces the temporal and spatial features of the observed HCHO column, but display regional biases which are attributed mainly to incorrect biogenic VOC emissions, calculated with the Model of Emissions of Gases and Aerosol from Nature (MEGAN) algorithm. These "bottom-up" or a-priori emissions are corrected through a Bayesian inversion of the OMI HCHO observations. Resulting "top-down" or a-posteriori isoprene emissions are lower than "bottom-up" by 40% over the Balkans and by 20% over Southern Germany, and higher by 20% over Iberian Peninsula, Greece and Italy. We conclude that OMI satellite observations of HCHO can provide a quantitative "top-down" constraint on the European "bottom-up" VOC inventories.

scholarly journals A new discrete wavelength BUV algorithm for consistent volcanic SO<sub>2</sub> retrievals from multiple satellite missions

2019 ◽  
Author(s):  
Bradford L. Fisher ◽  
Nickolay A. Krotkov ◽  
Pawan K. Bhartia ◽  
Can Li ◽  
Simon Carn ◽  
...  
Keyword(s):  
Sulfur Dioxide ◽  
Principal Component ◽  
Volcanic Eruptions ◽  
Climate Data ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Earth Observing System ◽  
Paper Supplement ◽  
Process Measurements ◽  
Pca Algorithm

Abstract. This paper describes a new discrete wavelength algorithm developed for retrieving volcanic sulfur dioxide (SO2) vertical column density (VCD) from UV observing satellites. The Multi-Satellite SO2 algorithm (MS_SO2) simultaneously retrieves column densities of sulfur dioxide, ozone, Lambertian Effective Reflectivity (LER) and its spectral dependence. It is used operationally to process measurements from the heritage Total Ozone Mapping Spectrometer (TOMS) on board NASA's Nimbus-7 satellite (N7/TOMS: 1978–1993) and from the current Earth Polychromatic Imaging Camera (EPIC) on board Deep Space Climate Observatory (DSCOVR: 2015–) from the Earth-Sun Lagrange (L1) orbit. Results from MS_SO2 algorithm for several volcanic cases were validated using the more sensitive principal component analysis (PCA) algorithm. The PCA is an operational algorithm used by NASA to retrieve SO2 from hyperspectral UV spectrometers, such as Ozone Monitoring Instrument (OMI) on board NASA’s Earth Observing System Aura satellite and Ozone Mapping and Profiling Suite (OMPS) on board NASA-NOAA Suomi National Polar Partnership (S-NPP) satellite. For this comparative study, the PCA algorithm was modified to use the discrete wavelengths of the Nimbus7/TOMS instrument, described in S1 of the paper supplement. Our results demonstrate good agreement between the two retrievals for the largest volcanic eruptions of the satellite era, such as 1991 Pinatubo eruption. To estimate SO2 retrieval uncertainties we use radiative transfer simulations explicitly accounting for volcanic sulfate and ash aerosols. Our results suggest that the discrete-wavelength MS_SO2 algorithm, although less sensitive than hyperspectral PCA algorithm, can be adapted to retrieve volcanic SO2 VCDs from contemporary hyperspectral UV instruments, such as OMI and OMPS, to create consistent, multi-satellite, long-term volcanic SO2 climate data records.

scholarly journals Improving global detection of volcanic eruptions using the Ozone Monitoring Instrument (OMI)

2016 ◽  
Vol 9 (11) ◽  
pp. 5487-5498 ◽  
Author(s):  
Verity J. B. Flower ◽  
Thomas Oommen ◽  
Simon A. Carn
Keyword(s):  
Traffic Control ◽  
Service Providers ◽  
Volcanic Eruptions ◽  
Volcanic Plume ◽  
Human Populations ◽  
Ozone Monitoring Instrument ◽  
User Input ◽  
Monitoring Instrument ◽  
Ozone Monitoring

Abstract. Volcanic eruptions pose an ever-present threat to human populations around the globe, but many active volcanoes remain poorly monitored. In regions where ground-based monitoring is present the effects of volcanic eruptions can be moderated through observational alerts to both local populations and service providers, such as air traffic control. However, in regions where volcano monitoring is limited satellite-based remote sensing provides a global data source that can be utilised to provide near-real-time identification of volcanic activity. This paper details a volcanic plume detection method capable of identifying smaller eruptions than is currently feasible, which could potentially be incorporated into automated volcanic alert systems. This method utilises daily, global observations of sulfur dioxide (SO2) by the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite. Following identification and classification of known volcanic eruptions in 2005–2009, the OMI SO2 data, analysed using a logistic regression analysis, permitted the correct classification of volcanic events with an overall accuracy of over 80 %. Accurate volcanic plume identification was possible when lower-tropospheric SO2 loading exceeded ∼ 400 t. The accuracy and minimal user input requirements of the developed procedure provide a basis for incorporation into automated SO2 alert systems.

scholarly journals Opportunistic validation of sulfur dioxide in the Sarychev Peak volcanic eruption cloud

2011 ◽  
Vol 4 (3) ◽  
pp. 3861-3875 ◽  
Author(s):  
S. A. Carn ◽  
T. M. Lopez
Keyword(s):  
Spatial Distribution ◽  
Sulfur Dioxide ◽  
Limited Data ◽  
Ozone Monitoring Instrument ◽  
Eruption Cloud ◽  
Kurile Islands ◽  
Volcanic Cloud ◽  
Ozone Monitoring ◽  
Lidar Observations ◽  
Sarychev Peak

Abstract. We report attempted validation of Ozone Monitoring Instrument (OMI) sulfur dioxide (SO2) retrievals in the stratospheric volcanic cloud from Sarychev Peak (Kurile Islands) in June 2009, through opportunistic deployment of a ground-based ultraviolet (UV) spectrometer (FLYSPEC) as the volcanic cloud drifted over Central Alaska. The volcanic cloud altitude (~12–14 km) was constrained using coincident CALIPSO lidar observations. By invoking some assumptions about the spatial distribution of SO2, we derive averages of FLYSPEC vertical SO2 columns for comparison with OMI SO2 measurements. Despite limited data, we find minimum OMI-FLYSPEC differences of ~5–6 % which support the validity of the operational OMI SO2 algorithm. These measurements represent the first attempt to validate SO2 in a stratospheric volcanic cloud using a mobile ground-based instrument, and demonstrate the need for a network of rapidly deployable instruments for validation of space-based volcanic SO2 measurements.

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