Publikationsdatum:
2017-04-04
Beschreibung:
In order to evaluate the influence of soil permeability on soil CO2 flux measurements
performed with the dynamic concentration method, several tests were carried out
using soils characterized by different permeability values and flow rates. A special device
was assembled in the laboratory to create a one-dimensional gas flow through a soil of
known permeability. Using the advective-diffusion theory, a physical model to predict
soil concentration gradients was also developed. The calculated values of CO2
concentrations at different depths were compared with those measured during the tests and
a good agreement was found. Four soils with different gas permeability (3.6 10 2 to
1.23 102 mm2) were used. The CO2 flux values were varied from 0.1 kg m 2 d 1 up
to 22 kg m 2 d 1. On the basis of these results, a new empirical equation for
calculating very accurate soil CO2 flux from dynamic concentration and soil permeability
values was proposed. As highlighted by the experimental data, the influence of soil
permeability on CO2 flux measurements depends on various factors, of which the flow
rate of the suction pump is the most important. Setting low values for the pumping flux
(0.4–0.8 L min 1), the mean error due to soil permeability was lower than 5%. Finally,
the method was tested by measuring the CO2 flux in a grid of 48 sampling sites on
Vulcano (Aeolian Islands, Italy), and the global error, affecting the CO2 flux
measurements in a real application, was evaluated.
Beschreibung:
Published
Beschreibung:
B05202
Beschreibung:
JCR Journal
Beschreibung:
reserved
Schlagwort(e):
CO2 flux measurements
;
volcanic areas
;
04. Solid Earth::04.08. Volcanology::04.08.01. Gases
Repository-Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Materialart:
article
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