Carbon dioxide (CO2) and methane (CH4) are the most important anthropogenically produced greenhouse gases and pose significant challenges for the global carbon cycle modelers in the changing climate. We use a top-down (inversion) method that uses observations of these gases from surface sites and remote sensing platforms, and an atmospheric chemistry-transport model (ACTM). Our joint analysis of CO2 and CH4 inversion results showed the importance of a priori fossil fuel emissions for inferring trends in CO2 sinks estimated for China. I will also discuss some other issues we face in the top-down modeling systems in relation with the terrestrial biospheric modeling. We also have developed a simple CO2 flux calculation method using total column CO2 measurements by OCO2, and estimated an anomalous CO2 source of 2-3 PgC due to the most recent El Nino event (2015-2016).
Dr. Prabir Patra is a senior Scientist at the Department of Environmental Geochemical Cycle Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC). His main research interest is to understand cycling of greenhouse gases (GHGs) and ozone-depleting substances (ODSs) using atmospheric chemistry-transport models (ACTMs). He is one of the main developers of JAMSTEC’s ACTM, and has been actively involved in all Transport model intercomparison (TransCom) experiments since the early 2000s.