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Title: Intercomparison of nitrogen-containing species in Nimbus 7 LIMS and SAMS Data

Journal Article · · J. Geophys. Res.; (United States)

Nitrogen dioxide (NO/sub 2/) and nitric acid (HNO/sub 3/) distributions were derived with a two-dimensional time-dependent model using N/sub 2/O, CH/sub 4/, and temperature measurements from the stratospheric and mesospheric sounder (SAMS) along with H/sub 2/O measurements from the limb infrared monitor of the stratosphere (LIMS) and O/sub 3/ measurements from the solar backscatter ultraviolet (SBUV) instrument. All three instruments (SAMS, LIMS, and SBUV) were aboard the Nimbus 7 satellite. The computed NO/sub 2/ and HNO/sub 3/ were compared with LIMS NO/sub 2/ and HNO/sub 3/ measurements. Calculated NO/sub 2/ is lower than the LIMS NO/sub 2/ in much of the lower stratosphere by about a factor of 4 or more. Differences in the upper stratosphere between derived NO/sub 2/ and LIMS NO/sub 2/ are within the photochemical uncertainties of the computation. Derived NO/sub 2/ is much larger than LIMS NO/sub 2/ at high latitudes in the upper stratosphere in December, indicating that dynamics and/or photochemistry in the atmosphere are different from those used in the model. Derived HNO/sub 3/ is in fairly good agreement with LIMS HNO/sub 3/ in the upper stratosphere. Derived and LIMS HNO/sub 3/ gradually become more different through the middle stratosphere and reach a fairly substantial disagreement in the lower stratosphere. The high-latitude maxima observed in LIMS HNO/sub 3/ are present at lower altitudes and at higher concentrations than those derived in the model computations. More significantly, the derived HNO/sub 3/ at polar latitudes is highest in the summer while LIMS HNO/sub 3/ is highest in the winter. Disagreements in the lower stratosphere between the computed and LIMS NO/sub 2/ and HNO/sub 3/ can only be reduced if two changes are made in the model computations: (1) additional lower stratospheric sources of odd nitrogen (other than N/sub 2/O+O(/sup 1/D)) are included and (2) a modified chemistry to allow the formation of HNO/sub 3/ at the expense of N/sub 2/O/sub 5/ is used.

Research Organization:
Atmospheric Chemistry and Dynamics Branch, NASA Goddard Space Flight Center, Greenbelt, Maryland
OSTI ID:
6706701
Journal Information:
J. Geophys. Res.; (United States), Vol. 92:D1
Country of Publication:
United States
Language:
English