Permafrost carbon cycles under multifactor global change: a modeling analysis
Abstract
Carbon dioxide (CO2) and methane (CH4) from permafrost zones are projected to be elevated under global change scenarios, but the magnitude and spatiotemporal variation of these greenhouse gas sources are still highly uncertain. Here we implement and evaluate the integration of a methane model into the Community Atmosphere-Biosphere Land Exchange model (CABLE v1.5 of CSIRO, Australia) in order to explore the carbon emissions under warming, elevated CO2 and altered precipitation. The weather data was obtained from a tundra site named eight mile lake in Alaska and the data of years 2004-2009 was used to tune and validate the model. First, data obtained from measurement were transformed to meet the input weather data required by the model. Second, model parameters regarding vegetation and soil were modified to accurately simulate the permafrost site. For example, we modified the resistivity of soil in the model so that the modeled energy balance was found to match with the observations. Currently, the modeled NPP are relatively higher but soil temperature is lower than the observations. Third, a new methane module is being integrated into the model. We simulate the methane production, oxidation and emission processes (ebullition, diffusion and plant-aided transport). We test new functions for soil pH and redox potential that impact microbial methane production and oxidation in soils. We link water table position (WTP) with the available amount of decomposable carbon for methanogens, in combination with spatially explicit simulation of soil temperature. We also validated the model and resolved the discrepancy between the model and observation. In this presentation, we will describe results of simulations to forecast CO2 and CH4 fluxes under climate change scenarios.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.B21D0394L
- Keywords:
-
- 0414 BIOGEOSCIENCES / Biogeochemical cycles;
- processes;
- and modeling;
- 0428 BIOGEOSCIENCES / Carbon cycling;
- 0429 BIOGEOSCIENCES / Climate dynamics;
- 0475 BIOGEOSCIENCES / Permafrost;
- cryosphere;
- and high-latitude processes