Experimental observation of signature changes in bulk soil electrical conductivity in response to engineered surface COb>2b> leakage

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• 作者：Xiaobing Zhou^a ; ^{xzhou@mtech.edu} ; Venkata R. Lakkaraju^a ; Martha Apple^b ; Laura M. Dobeck^c ; Kadie Gullickson^c ; Joseph A. Shaw^d ; Alfred B. Cunningham^e ; Lucian Wielopolski^f ; Lee H. Spangler^c
• 关键词：CO2 monitoring ; CO2 leakage ; CO2 sequestration ; Soil electrical conductivity ; Rainfall ; Soil moisture ; Carbon cycling ; Magnetic and electrical methods
• 刊名：International Journal of Greenhouse Gas Control
• 出版年：2012
• 出版时间：March, 2012
• 年：2012
• 卷：7
• 期：Complete
• 页码：20-29
• 全文大小：1226 K

文摘

Experimental observations of signature changes of bulk soil electrical conductivity (EC) due to COb>2b> leakage were carried out at a field site at Bozeman, Montana, to investigate the change of soil geophysical properties in response to possible leakage of geologically sequestered COb>2b>. The dynamic evolution of bulk soil EC was measured during an engineered surface leakage of COb>2b> through in situ continuous monitoring of bulk soil EC, soil moisture, soil temperature, rainfall rate, and soil COb>2b> concentration to investigate the response of soil bulk EC signature to COb>2b> leakage. Observations show that: (1) high soil COb>2b> concentration due to COb>2b> leakage enhances the dependence of bulk soil EC on soil moisture. The bulk soil EC is a linear multivariate function of soil moisture and soil temperature, the coefficient for soil moisture increased from 2.111 dS for the non-leaking phase to 4.589 dS for the COb>2b> leaking phase; and the coefficient for temperature increased from 0.003 dS/¡ãC for the non-leaking phase to 0.008 dS/¡ãC for the COb>2b> leaking phase. The dependence of bulk soil EC on soil temperature is generally weak, but leaked COb>2b> enhances the dependence, (2) after the COb>2b> release, the relationship between soil bulk EC and soil COb>2b> concentration observes three distinct COb>2b> decay modes. Rainfall events result in sudden changes of soil moisture and are believed to be the driving forcing for these decay modes, and (3) within each mode, increasing soil COb>2b> concentration results in higher bulk soil EC. Comparing the first 2 decay modes, it is found that the dependence of soil EC on soil COb>2b> concentration is weaker for the first decay mode than the second decay mode.