scholarly journals First experimental evidence for the CO<sub>2</sub>-driven origin of Stromboli's major explosions

2011 ◽  
Vol 3 (1) ◽  
pp. 411-430 ◽  
Author(s):  
A. Aiuppa ◽  
M. Burton ◽  
P. Allard ◽  
T. Caltabiano ◽  
G. Giudice ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Co2 Emission ◽  
Weight Ratio ◽  
Co2 Flux ◽  
Recent Model ◽  
Stromboli Volcano ◽  
Plumbing System ◽  
Gas Leakage ◽  
Basaltic Volcanoes ◽  
Monitoring Strategies

Abstract. We report on the first detection of CO2 flux precursors of the till now unforecastable larger than normal ("major") explosions that intermittently occur at Stromboli volcano (Italy). Automated survey of the crater plume emissions in the period 2006–2010, during which 12 such explosions happened, demonstrate that these events are systematically preceded by a brief phase of increasing CO2/SO2 weight ratio (up to >40) and CO2 flux (>1300 t/d) with respect to the time-averaged values of 3.7 and ~500 t/d typical for standard Stromboli's activity. These signals are best explained by the accumulation of CO2-rich gas at a discontinuity of the plumbing system (decreasing CO2 emission at the surface), followed by increasing gas leakage prior to the explosion. Our observations thus support the recent model of Allard (2010) for a CO2-rich gas trigger of recurrent major explosions at Stromboli, and demonstrate the possibility to forecast these events in advance from geochemical precursors. These observations and conclusions have clear implications for monitoring strategies at other open-vent basaltic volcanoes worldwide.

scholarly journals First observational evidence for the CO<sub>2</sub>-driven origin of Stromboli's major explosions

Solid Earth ◽  
2011 ◽  
Vol 2 (2) ◽  
pp. 135-142 ◽  
Author(s):  
A. Aiuppa ◽  
M. Burton ◽  
P. Allard ◽  
T. Caltabiano ◽  
G. Giudice ◽  
...  
Keyword(s):  
Co2 Emission ◽  
Weight Ratio ◽  
Co2 Flux ◽  
Observational Evidence ◽  
Recent Model ◽  
Stromboli Volcano ◽  
Plumbing System ◽  
Gas Leakage ◽  
Basaltic Volcanoes ◽  
Monitoring Strategies

Abstract. We report on the first detection of CO2 flux precursors of the till now unforecastable "major" explosions that intermittently occur at Stromboli volcano (Italy). An automated survey of the crater plume emissions in the period 2006–2010, during which 12 such explosions happened, demonstrated that these events are systematically preceded by a brief phase of increasing CO2/SO2 weight ratio (up to >40) and CO2 flux (>1300 t d−1) with respect to the time-averaged values of 3.7 and ~500 t d−1 typical for standard Stromboli's activity. These signals are best explained by the accumulation of CO2-rich gas at a discontinuity of the plumbing system (decreasing CO2 emission at the surface), followed by increasing gas leakage prior to the explosion. Our observations thus supports the recent model of Allard (2010) for a CO2-rich gas trigger of recurrent major explosions at Stromboli, and demonstrates the possibility to forecast these events in advance from geochemical precursors. These observations and conclusions have clear implications for monitoring strategies at other open-vent basaltic volcanoes worldwide.

scholarly journals O<sub>2</sub> : CO<sub>2</sub> exchange ratio for net turbulent flux observed in an urban area of Tokyo, Japan, and its application to an evaluation of anthropogenic CO<sub>2</sub> emissions

2020 ◽  
Vol 20 (9) ◽  
pp. 5293-5308
Author(s):  
Shigeyuki Ishidoya ◽  
Hirofumi Sugawara ◽  
Yukio Terao ◽  
Naoki Kaneyasu ◽  
Nobuyuki Aoki ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Urban Area ◽  
Co2 Emission ◽  
Co2 Flux ◽  
Co2 Exchange ◽  
Co2 Fluxes ◽  
Diurnal Cycles ◽  
Co2 Concentrations ◽  
Human Respiration ◽  
Two Peaks

Abstract. In order to examine O2 consumption and CO2 emission in a megacity, continuous observations of atmospheric O2 and CO2 concentrations, along with CO2 flux, have been carried out simultaneously since March 2016 at the Yoyogi (YYG) site located in the middle of Tokyo, Japan. An average O2 : CO2 exchange ratio for net turbulent O2 and CO2 fluxes (ORF) between the urban area and the overlaying atmosphere was obtained based on an aerodynamic method using the observed O2 and CO2 concentrations. The yearly mean ORF was found to be 1.62, falling within the range of the average OR values of liquid and gas fuels, and the annual average daily mean O2 flux at YYG was estimated to be −16.3 µmol m−2 s−1 based on the ORF and CO2 flux. By using the observed ORF and CO2 flux, along with the inventory-based CO2 emission from human respiration, we estimated the average diurnal cycles of CO2 fluxes from gas and liquid fuel consumption separately for each season. Both the estimated and inventory-based CO2 fluxes from gas fuel consumption showed average diurnal cycles with two peaks, one in the morning and another one in the evening; however, the evening peak of the inventory-based gas consumption was much larger than that estimated from the CO2 flux. This can explain the discrepancy between the observed and inventory-based total CO2 fluxes at YYG. Therefore, simultaneous observations of ORF and CO2 flux are useful in validating CO2 emission inventories from statistical data.

Dynamics of the shallow plumbing system investigated from borehole strainmeters and cameras during the 15 March, 2007 Vulcanian paroxysm at Stromboli volcano

2012 ◽  
Vol 357-358 ◽  
pp. 249-256 ◽  
Author(s):  
Alessandro Bonaccorso ◽  
Sonia Calvari ◽  
Alan Linde ◽  
Selwyn Sacks ◽  
Enzo Boschi
Keyword(s):  
Stromboli Volcano ◽  
Plumbing System

scholarly journals Different regulation of CO<sub>2</sub> emission from streams and lakes

2013 ◽  
Vol 10 (6) ◽  
pp. 10021-10053
Author(s):  
S. Halbedel ◽  
M. Koschorreck
Keyword(s):  
Co2 Emission ◽  
Water Reservoir ◽  
Co2 Flux ◽  
Co2 Concentration ◽  
Physical Factors ◽  
Regulation Mechanism ◽  
Schematic Model ◽  
Piston Velocity ◽  
Drinking Water Reservoir ◽  
Standing Waters

Abstract. It has become more and more evident that CO2 emission (FCO2) from freshwater systems is an important part in the global carbon cycle. Only few studies addressed the different mechanisms regulating FCO2 from lotic and lentic systems. In a comparative study we investigated how different biogeochemical and physical factors can affect FCO2 from streams and reservoirs. We examined the seasonal variability in CO2 concentrations and emissions from four streams and two pre-dams of a large drinking water reservoir located in the same catchment, and compared them with parallel measured environmental factors. All streams generally were supersaturated with CO2 over the whole year, while both reservoirs where CO2 sinks during summer stratification and sources after circulation. FCO2 from streams ranged from 23 to 355 mmol m–2 d–1 and exceeded the fluxes from the reservoirs (–24 to 97 mmol m–2 d–1). Both the generally high piston velocity (k) and CO2 oversaturation were responsible for the higher FCO2 from streams in comparison to lakes. In both, streams and reservoirs FCO2 was mainly controlled by the CO2 concentration (r = 0.86 for dams, r = 0.90 for streams), which was clearly affected by metabolism and nutrients in both systems. Besides CO2 concentration, also physical factors control FCO2 in lakes and streams. During stratification FCO2 in both pre-dams was controlled by primary production in the epilimnion, which led to a decrease of FCO2. During circulation when CO2 from the hypolimnion was mixed with the epilimnion and the organic matter mineralisation was more relevant, FCO2 increased. FCO2 from streams was physically controlled especially by geomorphological and hydrological factors regulating k, which is less relevant in low wind lakes. We developed a schematic model describing the role of the different regulation mechanism on FCO2 from streams and lakes. Taken together, FCO2 is generally mostly controlled by CO2 concentration in the surface water. Lake stratification is a very important factor regulating FCO2 from lakes via controlling CO2 concentration and metabolism. But FCO2 in heterotrophic streams is generally higher. The higher k values are responsible for the comparable high FCO2. On a Central European landscape scale CO2 emission from streams was more relevant than the CO2 flux from standing waters.

scholarly journals Environmental factors regulating winter CO<sub>2</sub> flux in snow-covered boreal forest soil, interior Alaska

2012 ◽  
Vol 9 (1) ◽  
pp. 1129-1159 ◽  
Author(s):  
Y. Kim ◽  
Y. Kodama
Keyword(s):  
Environmental Factors ◽  
Soil Temperature ◽  
Forest Soil ◽  
Atmospheric Pressure ◽  
Co2 Emission ◽  
Black Spruce ◽  
Co2 Flux ◽  
Atmospheric Temperature ◽  
Spruce Forest ◽  
Interior Alaska

Abstract. Winter CO2 flux is an important element to assess when estimating the annual carbon budget on regional and global scales. However, winter observation frequency is limited due to the extreme cold weather in sub-Arctic and Arctic ecosystems. In this study, the continuous monitoring of winter CO2 flux in black spruce forest soil of interior Alaska was performed using NDIR CO2 sensors at 10, 20, and 30 cm above the soil surface during the snow-covered period (DOY 357 to 466) of 2006/2007. The atmospheric pressure was divided into four phases: >1000 hPa (HP: high pressure); 985<P<1000 (IP: intermediate pressure); <986 hPa (LP: low pressure); and a snow-melting period (MP); for the quantification of the effect of the environmental factors determining winter CO2 flux. The winter CO2 fluxes were 0.22 ± 0.02, 0.23 ± 0.02, 0.25 ± 0.03, and 0.17 ± 0.02 gCO2-C/m2 d−1 for the HP, IP, LP, and MP phases, respectively. Wintertime CO2 emission represents 20 % of the annual CO2 emissions in this boreal black spruce forest soil. Atmospheric temperature, pressure, and soil temperature correlate at levels of 56, 25, and 31 % to winter CO2 flux, respectively, during the snow-covered period of 2006/2007, when snow depth experienced one of its lowest totals of the past 80 years. Atmospheric temperature and soil temperature at 5 cm depth, modulated by atmospheric pressure, were found to be significant factors in determining winter CO2 emission and fluctuation in snowpack. Regional/global process-based carbon cycle models should be reassessed to account for the effect of winter CO2 emissions, regulated by temperature and soil latent-heat flux, in the snow-covered soils of Arctic and sub-Arctic terrestrial ecosystems of the Northern Hemisphere.

scholarly journals Diurnal sampling reveals significant variation in CO2 emission from a tropical productive lake

2014 ◽  
Vol 74 (3 suppl 1) ◽  
pp. S113-S119 ◽  
Author(s):  
PCJ Reis ◽  
FAR Barbosa
Keyword(s):  
Co2 Emission ◽  
Co2 Flux ◽  
Tropical Lakes ◽  
Southeastern Brazil ◽  
Diurnal Changes ◽  
Lake Metabolism ◽  
Temperature Trends ◽  
Air Water Interface ◽  
Net Heterotrophy ◽  
Co2 Dynamics

It is well accepted in the literature that lakes are generally net heterotrophic and supersaturated with CO2 because they receive allochthonous carbon inputs. However, autotrophy and CO2undersaturation may happen for at least part of the time, especially in productive lakes. Since diurnal scale is particularly important to tropical lakes dynamics, we evaluated diurnal changes in pCO2and CO2 flux across the air-water interface in a tropical productive lake in southeastern Brazil (Lake Carioca) over two consecutive days. Both pCO2 and CO2 flux were significantly different between day (9:00 to 17:00) and night (21:00 to 5:00) confirming the importance of this scale for CO2 dynamics in tropical lakes. Net heterotrophy and CO2 outgassing from the lake were registered only at night, while significant CO2 emission did not happen during the day. Dissolved oxygen concentration and temperature trends over the diurnal cycle indicated the dependence of CO2 dynamics on lake metabolism (respiration and photosynthesis). This study indicates the importance of considering the diurnal scale when examining CO2emissions from tropical lakes.

scholarly journals HAZ Characterization of Automotive DP Steels by Physical Simulation

2019 ◽  
Vol 4 (1) ◽  
pp. 478-487
Author(s):  
Raghawendra Sisodia ◽  
Marcell Gáspár ◽  
Noureddine Guellouh
Keyword(s):  
Co2 Emission ◽  
Physical Simulation ◽  
Weight Ratio ◽  
High Strength ◽  
Steel Grade ◽  
Cooling Time ◽  
Dp Steel ◽  
Dp Steels ◽  
Gleeble 3500

DP steels were extensively used in the vehicles industry due to its extraordinary combined properties of strength, ductility, formability and weldability which contributed great significance in reducing strength to weight ratio and CO2 emission. High strength steel i.e. DP steels (3 different grades) were experimentally investigated and thermophysically simulated using Gleeble 3500 simulator to determine softening and hardening in heat affected zone. Samples were heated to different peak temperatures (1350 °C, 950 °C, 775 °C and 650 °C), two cooling time (t8.5/5 = 5 s and 30 s) and Rykalin 2D model were selected. The hardness and microstructure of the specimens were tested and analysed. For longer cooling time (t8.5/5= 30 s), we observed that softening occurs in all grade of investigated DP steels to all sub-regions. But for shorter cooling time i.e. t8.5/5= 5 s the softening is higher in intercritical HAZ compared to other sub-regions for all the types of DP steel with short cooling time (t8.5/5 = 5 s). However, the hardening zone in the CGHAZ occurs when Tmax is 1350 ºC for DP600, DP800 & DP1000 steels but it is more prominent in DP800 as compared to others two steel grade.

The December 2002–July 2003 effusive event at Stromboli volcano, Italy: Insights into the shallow plumbing system by petrochemical studies

2006 ◽  
Vol 155 (3-4) ◽  
pp. 263-284 ◽  
Author(s):  
P. Landi ◽  
L. Francalanci ◽  
M. Pompilio ◽  
M. Rosi ◽  
R.A. Corsaro ◽  
...  
Keyword(s):  
Stromboli Volcano ◽  
Plumbing System

scholarly journals Totally Ecofriendly Synthesis of Silver Nanoparticles from Aqueous Dissolutions of Polysaccharides

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
M. A. Garza-Navarro ◽  
J. A. Aguirre-Rosales ◽  
E. E. Llanas-Vázquez ◽  
I. E. Moreno-Cortez ◽  
A. Torres-Castro ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Experimental Evidence ◽  
Weight Ratio ◽  
Spectroscopic Techniques ◽  
Contrast Imaging ◽  
Synthesis Mechanism ◽  
Synthesis Of Nanoparticles ◽  
Means Of Transmission ◽  
Experimental Findings ◽  
Z Contrast

In this contribution, a totally ecofriendly synthesis of silver nanoparticles from aqueous dissolution of polysaccharides is reported. The synthesis of nanoparticles was performed using aqueous dissolutions of silver nitrate (AgNO3) and carboxymethyl-cellulose (CMC) as both reducing and stabilization agent and using different AgNO3 : CMC weight ratios. Resultant yellowish to reddish dispersions were characterized by means of transmission electron microscopy and their related techniques, such as bright field and Z-contrast imaging and electron diffraction, as well as ultraviolet-visible and infrared spectroscopic techniques. The experimental evidence suggests that the morphology and particle size distribution of the silver nanoparticles depend on the AgNO3 : CMC weight ratio. This feature seems to be related to the stabilization given by the CMC matrix, which, according to our experimental findings, is steric in nature. Regarding such experimental evidence, a synthesis mechanism in which CMC acts as stabilizer and reducing agent is proposed.

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