Spatial and Temporal Variations in the Isotopic Composition of Atmospheric Nitrous Oxide

Abstract:

Variations in nitrous oxide (N­₂O) concentration in time and space are now measurable to the extent that inverse models can be used to infer the timing and geographic variation in its sources. A large uncertainty, however, is the influence of stratosphere-troposphere exchange, which brings N₂O-depleted air from the stratosphere to the surface. We show here that temporal and spatial variations in the nitrogen and oxygen isotopic composition of N₂O from a diverse set of atmospheric measurements, including aircraft sampling, firn air, and archived air dating back to 1978, can serve to significantly decrease uncertainties in the sources and distributions of N₂O emissions to the atmosphere.