SIMULATION OF STRATOSPHERIC N2O IN THE NCAR CCM2 - COMPARISON WITH CLAES DATA AND GLOBAL BUDGET ANALYSES

Global variability and budgets of stratospheric nitrous oxide (N2O) ar e studied using output from a stratospheric version of the NCAR Commun ity Climate Model. The model extends over 0-80 km, incorporating an N2 O-like tracer with tropospheric source and upper-stratospheric photoch emical sink, the latter parameterized using linear damping rates obtai ned from detailed two-dimensional model calculations. Results from the model over several seasonal cycles are compared with observations of N2O from the Cryogenic Limb Array Etalon Spectrometer instrument on th e Upper Atmosphere Research Satellite. The model produces N2O structur e and variability that is in reasonable agreement with the observation s. Global budgets of stratospheric N2O are furthermore analyzed using model output, based on the transformed Eulerian-mean, zonal-mean frame work. These budgets are used to quantify the importance of planetary w ave constituent transport in the stratosphere, for both slow seasonal variations and fast planetary wave events. These results demonstrate t hat such wave fluxes act to form and sharpen the strong subtropical N2 O gradients observed in satellite measurements.