Height-Lag Correlations of Density with Pressure and Temperature at Rocket Altitudes of the Stratosphere

Abstract

Unexpectedly large increases in the density of the stratosphere and mesosphere have been noted previously in association with atmospheric changes at remote altitudes. Modified forms of the hydrostatic equation and the equation of state suggest a positive correlation between the density at some altitude and the pressure and temperature at neighboring lower altitudes, under the controlling influence of vertical motion. In this paper, correlation coefficients are determined as a function of altitude separation, by season and latitude, on the basis of data at 20?60 km from four years of rocket soundings. Consistent patterns of correlation are found. These are characterized, in particular, by distinct maxima in the vertical arrays of correlation between pressure and density and between temperature and density, with the density at a fixed upper altitude. The highest pressure-density correlations are approximately +0.88 to +0.99, depending on latitude, season and height domain, and occur with a typical lag of 8 km. The corresponding range and height lag for maximum temperature-density correlations are +0.73 to +0.94, and 20 km. A physical-mathematical explanation for the occurrence of these maxima is suggested in terms of the pressure-scale height. Finally, the manner in which the correlation results may be used to predict the density at rocket altitudes is briefly indicated.