Data Assimilation of High‐Latitude Electric Fields: Extension of a Multi‐Resolution Gaussian Process Model (Lattice Kriging) to Vector Fields

Abstract

Ionospheric plasma convection is largely driven by the electrodynamic processes in the magnetosphere, which is controlled by the interaction between magnetosphere and solar wind. Thus, ion convection is a key indicator of the ionospheric responses to geomagnetic variations. Ion motion can enhance, recede, and even reverse in reacting to different interplanetary magnetic field (IMF) and solar wind conditions. During disturbed periods, enhanced ion convection transports midlatitude plasma into the polar cap, leading to tongues of ionization and patches, which can disrupt communication and navigation in the polar region (Buchau et al., 1983;Nishimura et al., 2021;Weber et al., 1984). The radio backscatter technique has been widely used to measure ion motions. For instance, the Super Dual Auroral Radar Network (SuperDARN) scans over azimuth sectors on a regular basis

Multiresolution Data Assimilation for Auroral Energy Flux and Mean Energy Using DMSP SSUSI, THEMIS ASI, and An Empirical Model

“…It is worth mentioning that the Lattice Kriging modeling is not limited to scalar field assimilation. Wu and Lu (2022) have extended it to assimilate vector fields such as electric fields under the curl-free condition and obtained the results with much smaller errors than the global SHF using the SuperDARN data. The fundamental principles are the same except that for the assimilation of electric fields, we need to project the basis functions of electrical potential (scalar) to electric fields (vector) and then project them onto the LOS direction, along which the observations are actually made (SuperDARN measures LOS ion drifts).…”

“…Lattice Kriging has already been used in the lower atmospheric studies like surface temperature analysis (Heaton et al., 2019; Wiens et al., 2020). Wu and Lu (2022) have extended this model to vector fields and assimilated high‐latitude electric fields using SuperDARN and Poker Flat Incoherent Scatter Radar (PFISR) data, which demonstrates its effectiveness in space weather studies. It is the first time that this model is applied to auroral assimilation.…”

Understanding Strong Neutral Vertical Winds and Ionospheric Responses to the 2015 St. Patrick's Day Storm Using TIEGCM Driven by Data‐Assimilated Aurora and Electric Fields

“…The Lattice Kriging modeling has been recently adopted for the data assimilation of aurora (Wu et al., 2022) and extended for the assimilation of electric fields (Wu & Lu, 2022). It has been shown to largely capture the temporal and spatial variability of real data.…”

pyDARN: A Python software for visualizing SuperDARN radar data

“…Grid data is a highly processed data product derived from FitACF data, which has been used with various models to calculate ionospheric electric fields and Joule heating rates (e.g., Matsuo et al, 2021;Wu and Lu, 2022). The LoS vectors are mapped within the cells of an equal-area grid, which is defined in the geomagnetic coordinates system with each cell measuring 1°in latitude, to eliminate biases that would derive from the much denser sampling over nearer radar range gates.…”