Accession Number:

ADA164636

Title:

The Neutral/Ion Chemistry of Sodium in the Stratosphere and Mesosphere.

Descriptive Note:

Technical rept.,

Corporate Author:

ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC CAMBRIDGE MA

Report Date:

1985-09-30

Pagination or Media Count:

59.0

Abstract:

Part A of the report presents results from our model calculation of the diurnal behavior of the neutral and ionic sodium species. It is shown that the concentration of Na above 90 km exerts a direct influence on the topside scale height of the atomic sodium layer in the mesosphere. The abundance of Na is controlled by the reaction rate for the clustering reaction which is the rate limiting step for the conversion of Na to Na. Downward transport of Na due to ion drift is also effective in reducing the sodium abundance around 90 km. The model can successfully simulate the observed topside scale height of the sodium layer by either using a slow rate for the clustering reaction or incorporating transport of Na. Part B assesses the possible impact of sodium species on the stratospheric chlorine cycle. Recent measurements of kinetic rates suggest that the bulk of the sodium psecies could be in the form of NaCl in the stratosphere. Since the sodium abundance is three orders of magnitude smaller than that of chlorine, NaCl is not likely to be an important chlorine reservoir. Photolysis of NaCl could provide a mechanism for recycling HCl to Cl in the lower stratosphere if it is as fast as 0.001s. However, the mechanism would not be effective if there exists another more stable form of sodium compound, such as NaHC03 or polymers of NaCl. Keywords Ionospheric chemistry Photochemistry Ion chemistry Upper atmosphere Ionospheric models D region E region.

Subject Categories:

  • Atmospheric Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE