Spatial variability of methane concentrations over Argentina. Satellite measurements compare to high resolution inventories

PULIAFITO, S. ENRIQUE; BERNÁ, LUCAS; BOLAÑO-ORTIZ, TOMÁS; PASCUAL, ROMINA; LÓPEZ NOREÑA, ANA

Santiago de Chile

Conferencia; The Global Emissions Initiative (GEIA). 19th Conference GEIA Santiago de Chile 2019; 2019

GEIA-Universidad de Chile

Argentina is an important livestock producer emitting an annual average (1990-2016) of 2900 Gg (±13%) of CH4 out of a total annual of 4000 Gg (±10%),representing 73% of the national methane emissions and 39% of national GHG emissions. We review the available methane concentrations over Argentinameasured from several spaceborne instruments such as SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography, on board ENVISAT; 2002-2009), GOSAT(Greenhouse gases observing satellite; since 2009); and TROPOMI (TROPOspheric Monitoring Instrument on board the Copernicus Sentinel-5 Precursor satellite; since 2018). We evaluate total column and when possible tropospheric profiles, and compared to two high resolution inventories: 1) a local national inventory GEAA (lat. 0.025° x long. 0.025°) prepared by our group which includes biomass burning, forest fires, energy production, residential consumption, transport, livestock and agricultural production; 2) a global inventory (lat. 0.1° x long. 0.1°) prepared by EDGARv4.2 (Emission Database for Atmospheric Research). Satellite data shows that latitudinal averages of the continental sector increases at a higher rate from south to north than the maritime sector, which is merely constant. The continental slope increase is 10 ppb per degree up to latitude 28 S were remains approximately constant at 1870 ppb level. Theselatitudinal increase from south to north is consistent with the emissions inventory from 45S to 28S, where most of the anthropogenic national activities are reported. From a temporal perspective, monthly average tropospheric concentration values have a stational amplitude of 40-50 ppb. Absolute concentration values have been increasing since 2007 at a rate of 0.26% per month (GOSAT first layer surfaces data). However total emissions calculated from the inventories do not follow the same annual increase as shown by the satellite data. Annual emissions have been relative stable with a slight 5% decrease