Control of equatorial ionospheric morphology by atmospheric tides

TLDR

A 1000‑km scale longitudinal variation in ionospheric densities, previously unexplained, reveals an unexpected link between tropospheric weather and ionospheric conditions despite strong damping of upward propagating tides. The observations can be explained by considering the dynamo interaction of non‑migrating diurnal atmospheric tides with the daytime lower ionosphere (E‑layer). Ionospheric densities vary with the strength of non‑migrating diurnal atmospheric tides driven by tropical weather, making persistent rainstorms a key factor for space weather.

Abstract

A newly discovered 1000‐km scale longitudinal variation in ionospheric densities is an unexpected and heretofore unexplained phenomenon. Here we show that ionospheric densities vary with the strength of non‐migrating, diurnal atmospheric tides that are, in turn, driven mainly by weather in the tropics. A strong connection between tropospheric and ionospheric conditions is unexpected, as these upward propagating tides are damped far below the peak in ionospheric density. The observations can be explained by consideration of the dynamo interaction of the tides with the lower ionosphere (E‐layer) in daytime. The influence of persistent tropical rainstorms is therefore an important new consideration for space weather.