G. Chisham
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View article: The Impact of Adaptive High‐Latitude Coordinates
The Impact of Adaptive High‐Latitude Coordinates Open
The high‐latitude ionosphere can be divided into three regions dominated by different types of coupling and characterized by distinctive behaviors. These are the polar cap, the auroral region, and the sub‐auroral region. Their locations ar…
View article: Automated Identification of Auroral Luminosity Boundaries using pyIntensityFeatures
Automated Identification of Auroral Luminosity Boundaries using pyIntensityFeatures Open
Imagers that observe emissions from the atmosphere are commonly used to study various ionospheric phenomena.  These phenomena include the auroral oval, equatorial plasma bubbles, and travelling ionospheric disturbances.  A diffic…
View article: Using vorticity to characterise meso-scale ionospheric flow variations
Using vorticity to characterise meso-scale ionospheric flow variations Open
Using line-of-sight velocity measurements made by SuperDARN (The Super Dual Auroral Radar Network) radars with overlapping fields of view, it is possible to estimate the vorticity of the ionospheric convection flow over a wide range of sca…
View article: ALF - A Probabilistic Auroral Location Forecast derived from Far-Ultraviolet Auroral Boundaries and Geomagnetic Activity
ALF - A Probabilistic Auroral Location Forecast derived from Far-Ultraviolet Auroral Boundaries and Geomagnetic Activity Open
Using auroral boundaries determined from far ultraviolet images of the aurora (Chisham et al., 2022), we have examined auroral occurrence with respect to magnetic latitude, local time and the Kp index. Our results show that auroral occurre…
View article: Evaluating Auroral Forecasts Against Satellite Observations Under Different Levels of Geomagnetic Activity
Evaluating Auroral Forecasts Against Satellite Observations Under Different Levels of Geomagnetic Activity Open
The aurora and associated high energy particles and currents pose a space weather hazard to communication networks and ground‐based infrastructure. Forecasting the location of the auroral oval forms an integral component of daily space wea…
View article: The Spatial Variation of Large‐ and Meso‐Scale Plasma Flow Vorticity Statistics in the High‐Latitude Ionosphere and Implications for Ionospheric Plasma Flow Models
The Spatial Variation of Large‐ and Meso‐Scale Plasma Flow Vorticity Statistics in the High‐Latitude Ionosphere and Implications for Ionospheric Plasma Flow Models Open
The ability to understand and model ionospheric plasma flow on all spatial scales has important implications for operational space weather models. This study exploits a recently developed method to statistically separate large‐scale and me…
View article: Influences of Space Weather Forecasting Uncertainty on Satellite Conjunction Assessment
Influences of Space Weather Forecasting Uncertainty on Satellite Conjunction Assessment Open
A significant increase in the number of anthropogenic objects in Earth orbit has necessitated the development of satellite conjunction assessment and collision avoidance capabilities for new spacecraft. Neutral mass density variability in …
View article: A Comparison of Auroral Oval Proxies With the Boundaries of the Auroral Electrojets
A Comparison of Auroral Oval Proxies With the Boundaries of the Auroral Electrojets Open
The boundaries of the auroral oval and auroral electrojets are an important source of information for understanding the coupling between the solar wind and the near‐earth plasma environment. Of these two types of boundaries the auroral ele…
View article: High-time-resolution analysis of meridional tides in the upper mesosphere and lower thermosphere at mid-latitudes measured by the Falkland Islands SuperDARN radar
High-time-resolution analysis of meridional tides in the upper mesosphere and lower thermosphere at mid-latitudes measured by the Falkland Islands SuperDARN radar Open
Solar tides play a major role in the dynamics of the upper mesosphere and lower thermosphere (MLT). Hence, a comprehensive understanding of these tides is important for successful modelling of the MLT region. Most ground-based observations…
View article: A comparison of auroral oval proxies with the boundaries of the auroral electrojets
A comparison of auroral oval proxies with the boundaries of the auroral electrojets Open
The boundaries of the auroral oval and auroral electrojets are an important source of information for understanding the coupling between the solar wind and the near-earth plasma environment. Of these two types of boundaries the auroral ele…
View article: Influences of Space Weather Forecasting Uncertainty on Satellite Conjunction Assessment
Influences of Space Weather Forecasting Uncertainty on Satellite Conjunction Assessment Open
A significant increase in the number of anthropogenic objects in Earth orbit has necessitated the development of satellite conjunction assessment and collision avoidance capabilities for new spacecraft. Often, the greatest source of uncert…
View article: Extreme Birkeland Currents Are More Likely During Geomagnetic Storms on the Dayside of the Earth
Extreme Birkeland Currents Are More Likely During Geomagnetic Storms on the Dayside of the Earth Open
We examine the statistical distribution of large‐scale Birkeland currents measured by the Active Magnetosphere and Planetary Electrodynamics Response Experiment in four unique categories of geomagnetic activity for the first time: quiet ti…
View article: A comparison of auroral oval proxies with the boundaries of the auroral electrojets
A comparison of auroral oval proxies with the boundaries of the auroral electrojets Open
This is a dataset of electrojet boundaries found along the 105° magnetic meridan. The algorithm is explained in a paper currently in the submission stage, with the same title as this dataset, along with the presentation and investigation o…
View article: Separating Contributions to Plasma Vorticity in the High‐Latitude Ionosphere From Large‐Scale Convection and Meso‐Scale Turbulence
Separating Contributions to Plasma Vorticity in the High‐Latitude Ionosphere From Large‐Scale Convection and Meso‐Scale Turbulence Open
Measurements of ionospheric flow vorticity can be used for studying ionospheric plasma transport processes, such as convection and turbulence, over a wide range of spatial scales. Here, we analyze probability density functions (PDFs) of io…
View article: Reply on RC2
Reply on RC2 Open
Abstract. Solar tides play a major role in the dynamics of the upper mesosphere and lower thermosphere (MLT). Hence, a comprehensive understanding of these tides is important for successful modelling of the MLT region. Most ground-based ob…
View article: Reply on RC1
Reply on RC1 Open
Abstract. Solar tides play a major role in the dynamics of the upper mesosphere and lower thermosphere (MLT). Hence, a comprehensive understanding of these tides is important for successful modelling of the MLT region. Most ground-based ob…
View article: A Model of High Latitude Ionospheric Convection Derived From SuperDARN EOF Model Data
A Model of High Latitude Ionospheric Convection Derived From SuperDARN EOF Model Data Open
Forecasting of the effects of thermospheric drag on satellites will be improved significantly with better modeling of space weather effects on the high‐latitude ionosphere, in particular the Joule heating arising from electric field variab…
View article: Ground-based and additional science support for SMILE
Ground-based and additional science support for SMILE Open
The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field …
View article: High-time resolution analysis of meridional tides in the upper mesosphere and lower thermosphere at mid-latitudes measured by the Falkland Islands SuperDARN radar
High-time resolution analysis of meridional tides in the upper mesosphere and lower thermosphere at mid-latitudes measured by the Falkland Islands SuperDARN radar Open
Solar tides play a major role in the dynamics of the upper mesosphere and lower thermosphere (MLT). Hence, a comprehensive understanding of these tides is important for successful modelling of the MLT region. Most ground-based observations…
View article: Forecasting High-Latitude Ionospheric Convection Using the BAS Reanalysis of SuperDARN Data
Forecasting High-Latitude Ionospheric Convection Using the BAS Reanalysis of SuperDARN Data Open
Forecasting of the effects of thermospheric drag on satellites will be improved significantly with more accurate modelling of space weather effects on the high-latitude ionosphere, in particular the Joule heating arising from electric fiel…
View article: The balance between turbulent and convection-driven plasma vorticity in the Earth’s ionosphere
The balance between turbulent and convection-driven plasma vorticity in the Earth’s ionosphere Open
Measurements of ionospheric flow vorticity can be used for studying ionospheric plasma transport processes, such as convection and turbulence, over a wide range of spatial scales. Here, we present the spatial variation across the northern …
View article: Extreme Birkeland currents are more likely during geomagnetic storms on the dayside of the Earth
Extreme Birkeland currents are more likely during geomagnetic storms on the dayside of the Earth Open
We combine methods to identify substorms and geomagnetic storms into a single, novel method that identifies four categories: quiet times, storm only, substorm only, substorms in storms. We employ Birkeland current density data from the Act…
View article: Dual boundary coordinates in polar magnetosphere-ionosphere studies
Dual boundary coordinates in polar magnetosphere-ionosphere studies Open
The high latitude ionosphere, which coincides with the Arctic and Antarctic regions, is a complex region that is strongly coupled with the magnetosphere, neutral atmosphere, and the solar wind.  The high latitude ionosphere may be div…
View article: A Quantitative Comparison of High Latitude Electric Field Models During a Large Geomagnetic Storm
A Quantitative Comparison of High Latitude Electric Field Models During a Large Geomagnetic Storm Open
Models of the high‐latitude ionospheric electric field (EF) are commonly used to specify the magnetospheric forcing in thermosphere or whole atmosphere models. The use of decades‐old models based on spacecraft data is still widespread. Cur…
View article: A quantitative comparison of high latitude electric field models during a large geomagnetic storm
A quantitative comparison of high latitude electric field models during a large geomagnetic storm Open
Models of the high-latitude ionospheric electric field are commonly used to specify the magnetospheric forcing in thermosphere or whole atmosphere models. The use of decades-old models based on spacecraft data is still widespread. Currentl…
View article: Ionospheric Boundaries Derived From Auroral Images
Ionospheric Boundaries Derived From Auroral Images Open
This paper presents updated methods for locating the Poleward and Equatorward Auroral Luminosity Boundaries (PALB and EALB) directly from IMAGE Far UltraViolet (FUV) images of the Northern Hemisphere auroral oval. Separate boundaries are d…
View article: High latitude ionospheric electric field models comparison
High latitude ionospheric electric field models comparison Open
<p>Modern high latitude ionospheric electric field models have been developed to incorporate advances in data availability, however the use of older spacecraft-based models is still widespread.&#160; AENeAS (Advanced Ensemble ele…
View article: Distributions of Birkeland Current Density Observed by AMPERE are Heavy‐Tailed or Long‐Tailed
Distributions of Birkeland Current Density Observed by AMPERE are Heavy‐Tailed or Long‐Tailed Open
We analyze probability distributions of Birkeland current densities measured by the Active Magnetosphere and Planetary Electrodynamics Response Experiment. We find that the distributions are leptokurtic rather than normal and they are some…
View article: A Statistical Model of Vorticity in the Polar Ionosphere and Implications for Extreme Values
A Statistical Model of Vorticity in the Polar Ionosphere and Implications for Extreme Values Open
Measurements of vorticity in the Earth's ionosphere enable the characterization of turbulent structure in the ionospheric plasma flow and how it varies spatially in relation to large‐scale magnetic field‐aligned current (FAC) systems. We h…
View article: Data‐Driven Basis Functions for SuperDARN Ionospheric Plasma Flow Characterization and Prediction
Data‐Driven Basis Functions for SuperDARN Ionospheric Plasma Flow Characterization and Prediction Open
The archive of plasma velocity measurements from the Super Dual Auroral Radar Network (SuperDARN) provides a rich data set for the investigation of magnetosphere‐ionosphere‐thermosphere coupling. However, systematic gaps in this archive ex…