A5101635820- Ionosphere and magnetosphere dynamics
- Earthquake Detection and Analysis
- GNSS positioning and interference
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- earthquake and tectonic studies
- Geophysics and Gravity Measurements
- Seismic Waves and Analysis
- Seismology and Earthquake Studies
- Stellar, planetary, and galactic studies
- Ferroelectric and Negative Capacitance Devices
- Astrophysics and Star Formation Studies
- Semiconductor materials and devices
- Geophysical and Geoelectrical Methods
- Methane Hydrates and Related Phenomena
- Astro and Planetary Science
- Ocean Waves and Remote Sensing
- Advanced Optical Sensing Technologies
- Energy and Environmental Systems
- Geochemistry and Geologic Mapping
- Advanced Image Processing Techniques
- Optical Systems and Laser Technology
- Image and Signal Denoising Methods
- Infrared Target Detection Methodologies
- CCD and CMOS Imaging Sensors
National Cheng Kung University
2015-2024
National Central University
2008-2024
Space Telescope Science Institute
2012-2024
Nagoya University
2020
High Altitude Observatory
2020
Table Mountain Optics (United States)
2020
National University of Singapore
2017
Singapore Science Park
2017
Kyoto University
2001-2012
National Yunlin University of Science and Technology
2008
The global ionospheric map (GIM) is used to observe variations in the total electron content (TEC) of positioning system (GPS) associated with 35 M ≥ 6.0 earthquakes that occurred China during 10‐year period 1 May 1998 30 April 2008. statistical result indicates GPS TEC above epicenter often pronouncedly decreases on day 3–5 before 17 6.3 earthquakes. GIM and density profiles probed by six microsatellites FORMOSAT3/COSMIC (F3/C) are further employed simultaneously seismoionospheric anomalies...
[1] An earthquake of magnitude 9.0 occurred near the east coast Honshu (Tohoku area), Japan, producing overwhelming Earth surface motions and inducing devastating tsunamis, which then traveled into ionosphere significantly disturbed electron density within it (hereafter referred to as seismotraveling ionospheric disturbances (STIDs)). The total content (TEC) derived from nationwide GPS receiving networks in Japan Taiwan is employed monitor STIDs triggered by seismic tsunami waves Tohoku...
This paper presents monthly variations of the midlatitude summer nighttime anomaly (MSNA) ionosphere for first time by global observations FORMOSAT‐3/COSMIC (F3/C) mission. The is characterized greater (1800 LT ∼ 0200 LT) ionospheric electron density than during daytime (0800 1800 at middle latitudes months around June and December solstices. shown solstice was known as Weddell Sea Anomaly (WSA) occurring Antarctica nearby Pacific Ocean. demonstrates that WSA‐like feature also exists in...
Abstract Concentric traveling ionosphere disturbances (CTIDs) in total electron content triggered by Super Typhoon Meranti on 13 September 2016 are detected using the ground‐based Global Navigation Satellite Systems network Taiwan. The CTIDs emanated outward before typhoon landfall and lasted for more than 10 h. characteristics of agree with gravity wave theory exhibit spatial temporal scales periods ~8–30 min, horizontal wavelengths ~160–200 km, phase velocities ~106–220 m/s. We also...
[1] In this paper, the total electron content (TEC) of global ionosphere map (GIM) is used to detect seismoionospheric anomalies associated with 12 January 2010 M7 Haiti earthquake, and an ionospheric model applied simulate detected anomalies. The GIM temporal variation shows that TEC over epicenter significantly enhances on 11 2010, 1 day before earthquake. latitude-time-TEC (LTT) plots reveal three anomalies: (1) northern crest equatorial ionization anomaly (EIA) moves poleward, (2) TECs...
This paper provides the first three‐dimensional description of ionospheric density structure Weddell Sea Anomaly (WSA). The WSA is characterized by a nighttime greater than that in daytime region around Antarctic Peninsula during southern hemisphere summer. It was observed ground‐based ionosondes located Antarctica back 1950s and further investigated two‐dimensional maps over oceans using TEC measurements collected TOPEX/Poseidon recently. Although these have provided views for tracking...
We report seismo‐ionospheric precursors of anomalous decreases in the total electron content (TEC) appearing day 5 prior to an M9.3 earthquake, largest one last five decades, which occurred Sumatra‐Andaman, Indonesia on 26 December 2004. Sequences global ionosphere maps TEC derived from worldwide ground‐based receivers positioning system (GPS) are used statistically study temporal and spatial earthquake. It was found that precursor GPS around epicenter significantly reduced during afternoon...
Numerical simulations are performed to simulate atmospheric perturbations observed at ionospheric heights just after the 2011 off Pacific coast of Tohoku Earthquake. A time-dependent, two-dimensional, nonlinear, non-hydrostatic, compressible and neutral, numerical model is developed reproduce perturbations. An impulsive upward surface motion assumed as source Simulated 300-km altitude show remarkable agreement with oscillations in total electron content (TEC) when width about 250 km. In...
Abstract Two remarkable typhoon‐induced traveling ionospheric disturbances (TIDs) with concentric and northwest‐southeast (NW‐SE) alignments, respectively, associated gravity waves (CGWs) ionosphere instabilities possibly seeded by CGWs, were observed in total electron content (TEC) derived from ground‐based Global Navigation Satellite System networks Taiwan Japan when the Category 5 Super Typhoon Nepartak approached on 7 July 2016. The TIDs (CTIDs) first appear horizontal phase velocities...
In this paper, modifications of the ionospheric tidal signatures during 2009 stratospheric sudden warming (SSW) event are studied by applying atmospheric analysis to electron densities observed using radio occultation soundings FORMOSAT‐3/COSMIC. The indicates that zonal mean and major migrating components (DW1, SW2 TW3) decrease around time SSW, with 1.5–4 hour shifts in daily maximum EIA middle latitudes. typical SSW signature: a semi‐diurnal variation density, featuring an earlier...
[1] The ionospheric Weddell Sea Anomaly (WSA) was first reported more than five decades ago based on ionosonde data near the Antarctica peninsula. WSA is an structure characterized by a larger nighttime electron density daytime density. Recent satellite observations indicate that can extend from South America and to central Pacific. major physical mechanisms have been suggested for formation are equatorward neutral wind, electric field, photoionization, downward diffusion plasmasphere. On...
Abstract A new three‐dimensional GPS ionospheric tomography technique is developed that uses total electron content (TEC) data from the dense Global Position System (GPS) receiver network, Earth Observation Network (GEONET) in Japan, and it will not require an model as initial guess bias reconstruction of density. The GEONET operated by Geospatial Information Authority Japan consists more than 1200 receivers; this high density wide coverage helps to reconstruct distribution ionosphere with...
We present Herschel PACS photometry of 17 B- to M-type stars in the 30 Myr old Tucana-Horologium Association. This work is part Open Time Key Programme "Gas Protoplanetary Systems". 6 targets were found have infrared excesses significantly greater than expected stellar IR fluxes, including a previously unknown disk around HD30051. These six debris disks fitted with single-temperature blackbody models estimate temperatures and abundances dust systems. For five that show excess emission also...
In this study, we develop a three-dimensional ionospheric tomography with the ground-based global position system (GPS) total electron content observations. Because of geometric limitation GPS observation path, it is difficult to solve ill-posed inverse problem for density. Different from methods given by pervious studies, consider an algorithm combining least-square method constraint condition, in which gradient density tends be smooth horizontal direction and steep vicinity F2 peak. This...
Abstract Seismic waves can be detected in the Earth's atmosphere and ionosphere; however, their impacts on ionospheric electron density ( Ne ) structures near altitude of peak h m F 2 have not yet been fully determined due to lack sufficient observations sampled vertical direction. Here we apply a ground‐based Global Positioning System (GPS) receiving network Asia as well space‐based GPS occultation experiment board FORMOSAT‐3/COSMIC (F3/C) satellite vertically scan structures, which were...
Abstract We report the first observation of concentric traveling ionospheric disturbances (CTIDs) triggered by launch a SpaceX Falcon 9 rocket on 17 January 2016. The rocket‐triggered show shock acoustic wave signature in time rate change (time derivative) total electron content (TEC), followed CTIDs 8–15 min band‐pass filtering TEC. propagated northward with phase velocity 241–617 m/s and reached distances more than 1000 km away from source trajectory. characteristics periods 10.5–12.7...
Abstract A set of Observing System Simulation Experiments (OSSEs) are performed to assess the impact assimilating Constellation for Meteorology, Ionosphere, and Climate (COSMIC) electron density profiles ground‐based Global Navigation Satellite (GNSS) total content (TEC) observations in a whole atmosphere data assimilation system. The OSSEs using Whole Atmosphere Community Model with thermosphere‐ionosphere eXtension (WACCMX) provided by Data Assimilation Research Testbed (DART) ensemble...
Propagation of the initial ionospheric total electron content (TEC) disturbances generated by 2011 off Pacific coast Tohoku Earthquake at 05:46:23 UT on March 11, 2011, was investigated with ground-based Global Positioning System (GPS) receivers in east-Asian region. It found that disturbance formed a zonal wave front after earthquake occurrence. Four fronts this were observed to travel southward from Japan Taiwan velocity about 1,000– 1,700 m/s. This study further direction vector rotated...
Abstract This study examines an unexpected and extreme positive ionospheric response to a minor magnetic storm on August 5, 2019 by using global ionosphere specification (GIS) 3D electron density profiles obtained assimilating radio occultation total content (TEC) measurements of the recently launched FORMOSAT‐7/COSMIC‐2 satellites, ground‐based navigation satellite system (GNSS) TEC. The results reveal ∼300% enhancement equatorial ionization anomaly (EIA) crests, appearing over 200–300 km...
Using the physics-based thermosphere-ionosphere model (NCAR-TIEGCM) with an ensemble Kalman filter, this study reports first data assimilative analysis of ionosphere responses to solar eclipse on 21 August 2017. The system, using a 2-min assimilation cycle from ground-based GNSS observations, show dynamic variations equatorial ionization anomaly (EIA) due electrodynamic effects eclipse. Two major ionospheric are captured: (1) early appearance EIA at westward boundary moon shadow and (2)...
ABSTRACT Spatially resolved images of debris discs are necessary to determine disc morphological properties and the scattering phase function (SPF) thatantifies brightness scattered light as a angle. Current high-contrast imaging instruments have successfully several dozens around other stars, but few studies investigated trends in scattered-light, population uniform consistent manner. We combined Karhunen-Loeve Image Projection (KLIP) with radiative-transfer forward modelling order obtain...
This paper is the first study to employ a three‐dimensional physics‐based ionosphere model, SAMI3, coupled with National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) and Global Scale Wave simulate mesospheric lower thermospheric tidal effects on development of midlatitude summer nighttime anomaly (MSNA). Using this diurnal variation MSNA electron densities at 300 km altitude simulated both June solstice (day year (DOY) 167)...
Abstract We report that assimilating total electron content (TEC) into a coupled thermosphere‐ionosphere model by using the ensemble Kalman filter results in improved specification and forecast of eastward prereversal enhancement (PRE) electric field ( E field). Through data assimilation, ionospheric plasma density, thermospheric winds, temperature, compositions are adjusted simultaneously. The improvement duskside PRE calculation over prior state is achieved primarily intensification...
Abstract The Weddell Sea Anomaly (WSA) is a recurrent feature of the austral summer midlatitude ionosphere where electron densities are observed to maximize during local nighttime. In this study, tidal decomposition applied FORMOSAT‐3 (Formosa Satellite)/Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) total content (TEC) density observations between 2007 2012 quantify components dominating time spatial variation in WSA region. Our results present some first...