A5000176491- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- GNSS positioning and interference
- Geophysics and Gravity Measurements
- Atmospheric Ozone and Climate
- Radio, Podcasts, and Digital Media
- Higher Education Practises and Engagement
- Space Science and Extraterrestrial Life
- Cardiovascular and Diving-Related Complications
- Land Use and Ecosystem Services
- Oil Spill Detection and Mitigation
- IoT Networks and Protocols
- Astro and Planetary Science
- Magnetic Field Sensors Techniques
- Radiology practices and education
- Olfactory and Sensory Function Studies
- Soil Moisture and Remote Sensing
- Marine and coastal ecosystems
- Risk Perception and Management
- ICT in Developing Communities
- Higher Education and Employability
- Spacecraft Design and Technology
- Neonatal and Maternal Infections
East and North Hertfordshire NHS Trust
2021
Bureau of Meteorology
1998-2019
Services Australia
1990-2019
Bournemouth University
2018-2019
Sydney Orthopaedic Research Institute
1997
St Vincent's Hospital Sydney
1990
Derriford Hospital
1986
Abstract We report our analysis of ionospheric disturbances from the 15 January 2022 Tonga volcano eruption, using GPS data International GNSS Service network and ionosonde in Australian sector. Wave fluctuations with amplitudes ∼1 TECU altitude variations ∼100 km were observed data, respectively. In near‐field region around shortly after reveals that had an azimuthally anisotropic velocity profile, a peculiar minimum southwestward direction. Close resemblance is identified between profile...
The third FRONT (F‐region Radio and Optical measurement of Nighttime TID) campaign was carried out during the new‐moon period May–June 2003, in order to investigate geomagnetic conjugacy medium‐scale large‐scale traveling ionospheric disturbances (MSTIDs/LSTIDs) at midlatitudes. Seven all‐sky airglow imagers were operated Japan Australia. For almost all clear‐sky nights, we observed MSTIDs 630‐nm images with horizontal wavelengths 100–400 km propagating southwestward northwestward All them...
This paper describes the development of a major space storm during November 2–11, 1993. We discuss history contributing high‐speed stream, powerful combination solar wind transients and corotating interaction region which initiated storm, flow prolonged near‐Earth manifestations storm. The 8‐day period was unusually long; result stream (maximum speed 800 km/s) emanating from distended coronal hole. Storm onset accompanied by compression entire dayside magnetopause to within geosynchronous...
In March 2020, the WHO declared COVID-19 to be a global pandemic and since December millions of vaccines have been administered. To date, cases Guillain-Barré syndrome (GBS) following COVID vaccine (Pfizer, Johnson & Johnson, Janssen, AstraZeneca) reported. A 61-year-old woman developed bilateral asymmetrical lower motor neuron (LMN) facial weakness followed by limb symptoms, 10 days after receiving first dose AstraZeneca vaccine. The second patient was 56-year-old man who, 9 vaccine, LMN...
Abstract. A physical model of the coupled thermosphere and ionosphere has been used to determine accuracy predictions ionospheric response geomagnetic activity, assess our understanding processes. The is driven by empirical descriptions high-latitude electric field auroral precipitation, as measures strength magnetospheric sources energy momentum upper atmosphere. Both are keyed time-dependent TIROS/NOAA power index. output departure F region from normal climatological mean. 50-day interval...
We demonstrate that conventional ionosondes can provide long‐term observations of intermediate, descending, and transitional layers in the 100–200 km altitude region ionosphere. Using 15 consecutive days at Townsville, Australia, during SUNDIAL campaign September 1989, we tracked “birth” altitudes above 150 their systematic downward motion to 110 rates between 4 5 km/hr. The are compared with NCAR TIGCM simulations, results show: (i) layering process is identifiable meridional...
Abstract Infrastructures such as pipelines and power networks at low‐middle latitude regions have historically been considered relatively immune to geomagnetically induced currents (GICs). Over the past decade there an increasing number of investigations into impact GICs in long grounded conductors these latitudes. The Australian region network spans thousands kilometers from low middle approaching maximum solar cycle 24 recent findings studies located similar latitudes stimulated industry...
We report on a study of three intense ionospheric storms that occurred in September 1989. Using Dst as reference for storm onset and subsequent main recovery phases, we analyze the observed worldwide responses F region heights h m 2 densities N function universal local times, latitudinal domains, onset‐times; compare characteristics all storms. The following points are among major findings: (1) negative phase was dominant characteristic, with greatest intensity occurring regions which were...
This paper compares the observed behavior of F 2 layer ionosphere at Millstone Hill and Hobart with calculations from field line interhemispheric plasma (FLIP) model for solar maximum, solstice conditions in 1990. During study period daily 10.7 index varied by more than a factor (123 to 280), but 81‐day mean ( A ) was almost constant near 190. Calculations were performed without effects vibrationally excited N (N * which affects loss rate atomic oxygen ions. In case there is generally good...
Abstract. Temporal and spatial evolution of two high-altitude plasma bubbles (evening midnight) was observed on 4 April 2002, at geomagnetic conjugate points Sata, Japan (magnetic latitude 24° N), Darwin, Australia 22° S), using 630-nm airglow imagers. The apex height the reached ~1500km. upward velocity faster in evening (~170m/s 20:00-21:00 LT) than around midnight (~28m/s 23:00-00:00 LT). Bifurcating features into a smaller scale size ~50km were clearly seen for both bubbles, showing...
Using a comprehensive ionosphere model, we demonstrate that satellite measurements of solar EUV irradiances, neutral densities, and temperatures are consistent with Australian ionosonde the electron density from 2002 to 2006. Our approach is adjust model densities temperature determine changes needed reproduce density. These model‐derived found agree well GUVI instrument on TIMED for both magnetically quiet disturbed conditions. This technique opens up prospect using vast database improve...
Abstract The Hunga Tonga Volcano eruption launched a myriad of atmospheric waves that have been observed to travel around the world several times. These generated traveling ionospheric disturbances (TIDs) in ionosphere, which are known adversely impact radio applications such as Global Navigation Satellite Systems (GNSS). One GNSS application is Precise Point Positioning (PPP), can achieve cm‐level accuracy using single receiver, following typical convergence time 30 min 1 hr. A network...
Space weather events with their solar origin and distribution through the heliosphere affect whole magnetosphere‐ionosphere‐Earth system. Their real‐time monitoring forecasting are important for science technology. Here we discuss one of largest space Solar Cycle 23, in November 2004, which was also most difficult periods to forecast. Nine halo coronal mass ejections (CMEs), interacting on way interplanetary medium forming two geoeffective structures, exemplify complexity event. Real‐time...
A network of ionosondes in the Australian‐Japanese region recorded ionospheric response to a major magnetic storm that occurred near 2400 UT on November 3, 1993, when Kp reached 7. Most stations positive phase (increase) N m F 2 4 which was well produced by field line interhemispheric plasma (FLIP) model despite large relative increase molecular neutral densities. The appears be related storm‐induced abrupt uplift peak height ( h ) may have been caused wind surge or an electric field. winds...
Satellite and ground‐based observations from March 28 to 29, 1992, were combined in the assimilative mapping of ionospheric electrodynamics (AMIE) procedure derive realistic global distributions auroral precipitation convection which used as inputs National Center for Atmospheric Research (NCAR) thermosphere‐ionosphere general circulation model (TIGCM). Comparisons neutral winds made with Fabry‐Perot measurements meridional derived ionosondes. The peak equatorward occurred 1–2 hours later...
Abstract We compare, for the first time, geomagnetically-conjugate plasma bubbles observed by ground-based OI 630.0-nm all-sky imagers at Shigaraki, Japan (34.8°N, 136.1°E; magnetic latitude 25.4°N) and Darwin, Australia (12.4°S, 131.0°E; 22.0°S), with global-scale structures (≈10,000 km in longitude) equatorial anomaly simultaneously detected an 135.6-nm imager on IMAGE satellite ≈7 earth radii. As found previously, both hemisphere imaged consist of array small- to medium-scale (a few...
In the present paper, Global Oscillation Network Group (GONG) solar magnetograms are used to automatically identify active regions by thresholding line‐of‐sight component of magnetic field. The flare potential is predicted locating strong‐gradient polarity inversion lines (SPILs) and estimating their parameters. parameters interest length SPIL, a proxy for its curvature; maximum west‐east south‐north gradients field in vicinity; sum gradients, summation being performed along SPIL. Analysis...
Abstract Ionospheric data are valuable records of the behavior ionosphere, solar activity, and entire Sun‐Earth system. The critical for both societally important services scientific investigations upper atmospheric variability. This work investigates some difficulties pitfalls in maintaining long‐term geophysical measurements. investigation focuses on ionospheric parameters contained historical sets within National Oceanic Atmospheric Administration Geophysical Data Center Space Physics...
We present the first joint comparison of global measurements F region characteristics with three models used widely in specification ionospheric‐thermospheric system. The models, International Reference Ionosphere (IRI), field line interhemispheric plasma (FLIP) model, and Thermospheric‐Ionospheric General Circulation Model (TIGCM), represent a unique set capabilities major differences approaches to prevailing physics different levels computational complexity. database was developed by...
A unique data set of digital and digitized analog magnetic recordings from 22 stations in the Antarctic was used to construct southern hemisphere “equivalent” northern auroral electrojet index, AE , for two separate intervals disturbance (totaling seven days) June 1982. second index constructed using only 9 between ∼60°–70° geomagnetic south latitude showed small differences that all stations. For universal time interval (00–11 UT inclusive) when a reasonably good coverage ground exists...