Correlations between tropospheric and ionospheric parameters

Summary This paper discusses the general aspects of troposphere-ionosphere relationships and a suggested mechanism of a possible coupling between lower and upper atmosphere. The presentation includes results of a correlation analysis surface pressure and electron density of the ionosphericF2 layer for Washington, D.C., covering a time interval of 23 months. The correlation is significant for only three months and the sign of the correlation is not consistent. The three significant correlations between surface pressure andF2 electron density occur at times of an «index cycle»; i.e., the periodic fluctuations in the zonal circulation of the atmosphere and for a month of heavy hurricane activity. The review of correlations obtained by other authors also indicates that their significant correlations occur at times when intensive changes in the tropospheric circulation occur, especially in winter and spring (the time favored by index cycles) and at the beginning and retreat of the summer monsoon in India. The variable sign of correlation between surface pressure and ionospheric characteristics is considered to be the result of the ambiguity of surface pressure as an indicator for dynamic changes in the lower atmosphere which may possibly initiate certain changes in the upper atmosphere. It is speculated that the observed correlations are the effect of upward propagation of strong disturbances from the troposphere to the ionosphere. At the present time, however, no definite conclusion can be drawn as to the reality of the suggested troposphere-ionosphere relationships.