JGSEE: The Joint Graduate School of Energy and Environment NO.2 NO.2 NO.2
1. Introduction 1.1 Background 1.2 Objectives2. Materials and Methods 2.1 Study Site 2.2 Forest-DNDC Model 2.3 Model Input Parameters3. Results 3.1 Soil Carbon Dynamic 3.2 Soil CO2, N2O and NO Emission4. Conclusions
1.1 Background The greenhouse gas (GHG) are believed that lead to global warming. The changes in temperature, precipitation and CO2 concentration readily affect the carbon inputs and decomposition, and the soil nitrogen transformations. Soil respiration would be increased by global warming. Then it can release more CO2 that further exacerbates the global warming. However, both “the impact of climate change on soil carbon dynamics” and “the feedbacks of soil carbon dynamics on climate” are currently controversial.
1.2 ObjectivesIn order to unambiguously understand“the response of the Abies fabri forest ecosystem to the climate changes.”
2.1 Study SiteThe forest located in Gongga Mountain (China)as subtropical monsoon climate.(Source: http://commons.wikimedia.org/wiki/Category:Abies_fabri) (Source: Map from Google Earth, 2009)
2.2 Forest-DNDC Model FOREST-DNDC WETLAND-DNDC PnET-N-DNDCa hydrology-driven model an upland forest biogeochemical model (from photosynthesis and evapotranspiration – nitrification – denitrification and decomposition)
2.3 Model Input Parameters The values of CO2 conc., temp. Parameters for this study and precipitationincluding: site latitude ambient CO2 conc. Baseline (1990-1999) N conc. in precipitation Climate change scenarios (2090-2099) daily climate data soil properties forest propertiesOther input parameters were model default values.
3.1 Soil Carbon Dynamics SOC was determined by balance between litter inputs and heterotrophic respiration The forest floor pool Climate The increase of SOC Litterscenarios (kg C ha-1 yr -1) (kg C ha-1 yr-1) baseline 4111 4218 B1 4027 4125 A1B 3983 4076 A2 3940 4028 The mineral soil pool Climate The increase of SOC Litter scenarios (kg C ha-1 yr -1) (kg C ha-1 yr-1) baseline 2220 2105 B1 2235 2038 A1B 2244 2003 A2 2247 1975
3.2 Soil CO2, N2O and NO Emission Soil CO2 emissionThe GHGs emission was the highest when Temp. and precipitation were the highest.
3.2 Soil CO2, N2O and NO EmissionsSoil N2O and NO emission
Conclusions The IPCC climate scenarios substantially affect the soil carbon dynamics and GHG emissions in the A. fabri forest ecosystem. The Forest-DNDC simulation showed that the soil-borne GHG emissions increased significantly with rising temperature and precipitation. Compared with GHG emissions, the response of soil carbon dynamics to climate change was relatively less pronounced.