Airborne measurements indicate large methane emissions from the eastern Amazon basin

Abstract

Recent results from laboratory, field and remote sensing measurements suggest the presence of large methane emissions from the Amazon basin. Here we present regionally integrative, direct trace gas observations from two sites that confirm the presence of large fluxes of methane in eastern Amazônia. Air samples collected on aircraft near Santarém (2.9°S, 55.0°W) and Manaus (2.6°S, 60.0°W) in eastern and central Amazônia show large enhancements of CH 4 that are not seen at the NOAA/ESRL background sites in the tropical Atlantic Ocean. From the surface to about four km, enhancements averaging 34 ppb and up to 200 ppb occur throughout the year and we calculate emissions averaging 27 mg CH 4 /m 2 /day from upwind sources.