|
|
abstracts
Modeling of methane bubbles released from sea-floor gas hydrate
Akitomo Yamamoto, Yasuhiro Yamanaka, Eiichi Tajika
Massive methane release due to decomposition of methane hydrate in sea-floor sediments might have caused rapid global warming in the past (i.e. the Paleocene/Eocene thermal maximum, ~55Ma). However, the degree of global warming has not been estimated due to uncertainty over the proportion of methane flux from sea-floor to reach the atmosphere. According to the observation and model results of present methane-bubbling seep site, the methane bubble released from seafloor would not reach the atmosphere directly. Massive methane release would result in methane-saturated seawater, thus some methane bubble would reach the atmosphere.
This study investigated whether the massive methane released from sea-floor could reach the atmosphere or not, focusing on methane saturation in the water column required for methane bubble to reach the atmosphere. Using a one-dimensional numerical model, we calculated the required methane saturation in the water column and methane input from the sea-floor. We compared the required methane input with the amount of methane in the sediment in the form of methane hydrate and free gas. In most cases, our results suggest that the typical amount of methane in the sediment is significantly lower than the required methane input. It is, therefore, suggested that the massive quantity of methane bubbles released from sea-floor would not reach the atmosphere directly but would be dissolved in the seawater.
Akitomo Yamamoto, Graduate School of Environmental Science, Hokkaido University ,Environmental Science Bldg., N10 W5, Sapporo 060-0810, Japan, akitomo@ees.hokudai.ac.jp
Yasuhiro Yamanaka, Hokkaido University, Graduate School of Environmental Science, Japan
Eiichi Tajika, The University of Tokyo, Department of Earth and Planetary Science, Japan
Session: F1: Climate Forcings
Download Talk:
> YSM09_OralA_Yamamoto.pdf
|
|
