L11: Model lake methane emissions

Modeling lake methane emissions in Earth System Models

• @Zeli Tan

• zeli.tan@pnnl.gov

@Zeli Tan @Ruby Leung Huaxia Yao, John Melack, Hans-Peter Grossart, Joachim Jansen, Patrick Crill, Sivakiruthika Balathandayuthabani, @Khachik Sargsyan

Land - River - Human

E3SM

Lakes are important sentinel of climate change and may contribute half of natural methane (CH₄) emissions; however, no earth system model (ESM) has yet represented lake CH₄ dynamics. To fill this gap, we developed a process-based lake biogeochemical model in E3SM to represent CH₄ production and oxidation as well as CH₄ transport via both diffusion and ebullition under varying lake characteristics and environment. In addition, we also compiled a comprehensive lake CH₄ dataset including fine temporal CH₄ emission observations from 10 representative lakes and annual CH₄ emission observations from over 100 global lakes. We examined the parameter uncertainty of the model using a novel parameter uncertainty estimation tool. By calibration, the model can capture the observed water temperature, dissolved CH₄, and fine-resolution CH₄ diffusion and ebullition at those representative lakes. The developed model would provide useful skills for E3SM to estimate global lake CH₄ emissions and constrain the feedback between climate change and the global CH₄ cycle.

yes

zeli.tan@pnnl.gov