Stratospheric Nitrous Oxide Altitude Profiles at Various Latitudes

Abstract

A number of N2O profiles obtained in the troposphere and stratosphere at five latitudes are reported. The variability in the reported stratosphere N20 mixing ratios is substantial and indicates a strong dependence on both stratospheric transport and photochemistry. A profile obtained at Panama indicates a relatively large transport of N2O into the stratosphere at low latitudes. This profile represents the first one obtained in the tropics. From the observed data, area-averaged, global vertical eddy diffusion coefficients were derived that were found to be a factor of 1.5 to 3 times larger than those derived by Hunten from data obtained at locations not including the tropics. The derived eddy diffusion profile is heavily weighted by one single profile in the tropics and more observations are needed to substantiate this finding. The estimated flux of N20 into the stratosphere was equal to 15?1012 g(N) per year and the total stratospheric production of NOx was estimated to be 1.6?1012 g(N) per year. The atmospheric turnover time of N20 would he 100 years if photochemical reactions were the only sink for atmospheric N20.