Ionospheric convection and structure using ground-based digital ionosondes

Ground based digital ionosonde observations of the winter polar cap F region have been used to demonstrate that the magnetospherically induced ionospheric convection can be measured for the bottomside ionosphere. A number of measurements indicate that the drift direction is predominately anti-sunward with speeds that vary between 300 and 900 meters/second. Other measurements show a steady westward drift until local magnetic midnight and then a change to an eastward drift. The ionospheric drifts are consistent with the expected sunward return flows of the two cell polar plasma convection pattern. The utility of data from a network of digital ionosondes is enhanced through automatic scaling of parameters needed for research and radio wave propagation management. The values of hmF2 deduced by real-height analysis of automatically scaled Digisonde ionograms have been compared with simple methods based on routinely scaled ionospheric characteristics. Systematic discrepancies were found between the hmF2 values obtained from the simple methods and the real-height analysis. Overestimates of 15 to 20 km were found for the night data from five stations and low solar activity. Daytime discrepancies are normally less, with 80 percent showing agreement within + or - 10 km.