A new method for deriving trace gas emission inventories from satellite observations: The case of SO2 over China

A method is developed that allows the construction of spatial emission inventories. The method is applied for anthropogenic SO2 over China (0.25° × 0.25°). The Enhancement Ratio Method (ERM) allows for the calculation of SO2 emissions using relationships between gridded satellite measurements of SO2 and NO2 at low wind speeds, and satellite-based NOx emission estimates. Here, we derive SO2 emissions for five years (2007–2011). A large decrease of emissions during 2007–2009 and a modest increase between 2010 and 2011 is observed. The evolution of emissions over time calculated here is in general agreementwith bottom-up inventories, although differences exist, not only between the current inventory and other inventories but also among the bottom up inventories themselves. The ERM-derived emissions are consistent, spatially and temporally, with existing inventories.