Collaborative Research: The Impact of Lower Atmosphere Waves on Ionospheric Irregularities

Boston College, Chestnut Hill MA

Investigators

Abstract

The overarching goal of this award is to address one of the long-standing problems in ionospheric physicws by determining the role of the lower atmosphere waves in the day-to-day variability of the development of F-region ionospheric irregularities. The lateral distribution of ionospheric plasma density is normally fairly uniform except for the irregularities that are similar in appearance to air bubbles in a liquid. The steep gradients on the edges of the bubbles disrupt radio wave signals, and so pose a significant hazard to a number of critical applications. Aviation and shipping are increasingly reliant on satellite navigation and thus, the disruption of navigation radio signals by these ionospheric irregularities poses a threat to passengers and crew, as well as the crafts themselves. Understanding the day-to-day variability of ionospheric irregularities has been one of the long-standing challenges in space physics. The proposed work describes how a whole atmosphere model (WAM) that covers the altitude region from the ground to the top of the atmosphere together would be combined with an ionosphere plasma model that would be used to provide the background neutral winds and waves, plasma densities, and electrodynamic fields to drive a high-resolution ionospheric irregularity model. The goal is to determine what it is about the variability in the synoptic and large-scale background fields that is critical in explaining the variability of irregularity formation. A pilot study would be funded to carry out representative model calculations that would demonstrate the methodology of this unification of the thermosphere neutral atmosphere dynamical model with the Boston College plasma irregularity model. The broader impact of this study would be the potential development of a significant space weather forecasting capability based upon the tropospheric weather data imported into the whole atmosphere model formulation. The primary objective of the proposed work is to determine the characteristics and conditions of the background neutral atmosphere that lead to the initiation and development of ionospheric F-region irregularities at low latitudes. The work proposed would be based upon a collaboration between the University of Colorado (CU) and Boston College (BC) that would combine the large-scale whole atmospheric-ionosphere-electrodynamic modeling expertise at CU (Fuller-Rowell, Fang) with the BC group (Retterer, Groves, Valladares) that would provide the expertise regarding the irregularity modeling combined with observations from the LISN South American network developed under the leadership of Valladares. The motivation for this study is based upon the results of an ionospheric irregularity model simulation driven by the wind and wave fields derived by the CU whole atmosphere model with all the inherent variability associated with tropospheric dynamics. This simulation showed that irregularities grew naturally from the initial physical state without the need for additional artificial seeding. The proposed work builds upon recent findings that have exposed a strong connection between terrestrial and space weather.