HR: 1340h
AN: A53B-0900    [Abstracts]
TI: An Underground Laboratory for the Study of Thermodynamical Processes Associated With Small Thermal Perturbations
AU: * Crouzeix, C
EM: crouzeix@ipgp.jussieu.fr
AF: Laboratoire de geomagnetisme, IPGP 4 place Jussieu, Paris, 75005 France, Metropolitan
AU: Le Mouel, J
EM: lemouel@ipgp.jussieu.fr
AF: Laboratoire de geomagnetisme, IPGP 4 place Jussieu, Paris, 75005 France, Metropolitan
AU: Perrier, F
EM: frederic.perrier@cea.fr
AF: Laboratoire de geomagnetisme, IPGP 4 place Jussieu, Paris, 75005 France, Metropolitan
AU: Perrier, F
EM: frederic.perrier@cea.fr
AF: Service "Radioanalyse Chimie Environnement", CEA, Bruyeres-le-Chatel, 91680 France, Metropolitan
AU: Richon, P
EM: richon@dase.bruyeres.cea.fr
AF: Service "Radioanalyse Chimie Environnement", CEA, Bruyeres-le-Chatel, 91680 France, Metropolitan
AB: The abandonned underground quarry of Vincennes is located near Paris (France) at about 18 m under the ground surface. The quarry is convenient for the study of the underground microclimate and of the reaction of a natural complex system to small perturbations. Temperature, Rn-222 and CO$_2$ levels, relative humidity, pressure, and water dripping fluxes have been measured since 1999 in various places of the cavity. The mean temperature is about $12.6\deg$C, with spatial variations of the order of $0.4\deg$C. In the absence of thermal perturbations, temporal variations does not exceed $0.2\deg$C per year. We study their relation with the outside temperature variations, measured in two meteorological stations located near Paris. A comparison is also made with temperature measured by Cassini IV at the end of the 18th century under the Observatory of Paris. We have recently performed temperature measurements in the same galery, located about 28 m under the city center. In the quarry of Vincennes, temperature is mainly controlled by diffusion from outside temperature through the rock covering the quarry, and by natural ventilation occuring in winter through the main access pit. This pit is also instrumented, and the ventilation is quantified by Rn-222 and CO$_2$ measurements. Understanding the role of water is also crucial, as water drips from the ceiling and the walls, and the atmosphere is saturated in almost all the quarry. Temperature variations induce evaporation/condensation processes, that have been clearly evidenced by heating experiments with low power sources, performed since 2001 in a dedicated room of the quarry. Their investigation also shows a strong non-linearity of the response of such a medium to thermal perturbations, with long-term, and possibly irreversible, effects.
DE: 1610 Atmosphere (0315, 0325)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting