Toward Monitoring Greenhouse Gas Emissions from National to Regional and Urban Scales

Monitoring and verifying anthropogenic greenhouse gases (GHG) Emissions at high spatiotemporal resolution with observation-based evidence is desirable for climate policymakers. A multiple-scale nested GHG assimilation system, named GCASv3, was developed for quantifying anthropogenic GHG emissions at high spatiotemporal resolution. GCASv3 uses a four level nested scheme and consists of one global module and one regional module. The global model is capable of assimilating XCO₂ and XCH₄ data to infer global CO₂ flux and CH₄ emissions at 1⁰x1⁰ resolution, while the regional module is able to assimilate ground and satellite GHG observations to quantify anthropogenic GHG emissions on national, regional and urban scales at 27km, 9km and 1km resolution respectively. This presentation describes briefly the framework and the major components of GCASv3. Anthropogenic CO₂ emissions and CH₄ emissions inferred by GCASv3 at different scales are presented and discussed.