The Use of Assimilated Stratospheric Data in Constituent Transport Calculations

Abstract

Analysis of atmospheric data by assimilation of height and wind measurements into a general circulation model is routine in tropospheric analysis and numerical weather prediction. A stratospheric assimilation system has been developed at NASA/Goddard Space Flight Center. This unique system generates wind data that is consistent with the geopotential height (and temperature) field and the primitive equations in the general circulation model. These wind fields should offer a significant improvement over the geostrophic analysis normally used in the stratosphere. This paper reports the first known calculations to use data from an assimilation to calculate constituent transport in the stratosphere. Nitric acid (NHO3) during the LIMS period is studied. While there are still significant discrepancies between the calculated and observed HNO3, there are some remarkable successes. Particularly, the high-latitude time variance of the HNO3 is accurately captured. These studies suggest that data from an assimilation process offers tremendous potential for studying stratospheric dynamics, constituent transport, and chemistry.