Height‐integrated Pedersen and Hall conductivity patterns inferred from the TIROS‐NOAA satellite data

Publisher Website
Google Scholar
Abstract
The series of polar‐orbiting National Oceanic and Atmospheric Administration spacecraft TIROS, NOAA 6, and NOAA 7 have been monitoring the particle influx into the atmosphere since late 1978. This data base has been used to construct statistical global patterns of height‐integrated Pedersen and Hall conductivities for a discrete set of auroral activity ranges. The observations of energy influx and “characteristic electron energy” have been binned in a 1° latitude and 2° magnetic local time grid and ordered by an auroral activity index. This index is an estimate of the energy deposited into a single hemisphere by incident particles, a parameter generated directly from the particle observations and, therefore, internally consistent with the statistical patterns that are constructed. An average electron spectrum is associated with each characteristic energy, which enables a height profile of ionization rate in the upper atmosphere to be determined. The use of a pressure coordinate system insures that the normalized ionization rate profiles are independent of atmospheric model parameters. To create the statistical pattern of height‐integrated conductivities, however, vertical profiles of atmospheric temperature and composition are assumed, and the ion density enhancements are evaluated from a chemical balance between ion production and recombination based on an “effective” recombination coefficient. The data base can also provide the statistical pattern of particle heating rates and ionization rates over a three‐dimensional grid suitable as input to more sophisticated ionospheric and neutral thermospheric codes.