Budgets of Stratospheric Trace Gases from 2-D-Model Calculations and Satellite Observations

Summary

We have used satellite data from the SAMS, LIMS and BUV experiments to evaluate the stratospheric budgets of the odd nitrogen and odd oxygen families. Total odd nitrogen concentrations are calculated as a function of ΔN₂0 which is the difference between the mean tropospheric and the local stratospheric N₂0 mixing ratios. The proportionality factor φ is a function of global photochemical N₂0 loss and odd nitrogen production. While this approach seems to work well below 30 kms, there are major discrepancies between calculated and measured odd nitrogen concentrations above 30 km, which cannot be explained with uncertainties in the kinetic and photochemical input parameters and the N₂0 observations. This discrepancy in the odd nitrogen concentrations seems to be the reason for a significant overestimation of odd oxygen loss in the range 30 to 40 kms. These results could point toward major uncertainties in the photochemistry of odd nitrogen compounds in the middle stratosphere.