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22
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Introduction
Skills and Expertise
Education
October 2011 - September 2016
Publications
Publications (22)
The Hunga Tonga–Hunga Ha’apai (HTHH) undersea volcanic eruption that occurred at 04:15 UT on 15 January 2022 is one of the most explosive events in the modern era, and a vertical plume reached approximately 55 km, corresponding to a height of the lower mesosphere. The intense explosion and subsequent plume generated acoustic and atmospheric gravity...
To understand the mechanism of the increased frequency of intervals of pulsations of diminishing periods (IPDP), we analyzed IPDP‐type electromagnetic ion cyclotron (EMIC) waves that occurred on April 19, 2017, using ground and satellite observations. Observations by low‐altitude satellites and ground‐based magnetometers indicate that the increased...
Electrodynamic coupling between the ionospheric E and F regions is widely recognized as the underlying mechanism for generating medium-scale traveling ionospheric disturbances (MSTIDs) during nighttime at midlatitudes. Recently, the double-thin-shell approach has proven to be a useful tool for studying the E-F coupling. By using total electron cont...
Equatorial plasma bubbles are a phenomenon of plasma density depletion with small-scale density irregularities, normally observed in the equatorial ionosphere. This phenomenon, which impacts satellite-based communications, was observed in the Asia-Pacific region after the largest-on-record January 15, 2022 eruption of the Tonga volcano. We used sat...
We used the global navigation satellite system‐total electron content (TEC) and Super Dual Auroral Radar Network (SuperDARN) radar to elucidate the characteristics of the plasma bubble extending to midlatitudes over North America during a geomagnetic storm on 27 and 28 May 2017. To identify plasma bubbles, we analyzed the rate of the TEC index (ROT...
To elucidate the effect of solar wind dynamic pressure on the activities of ionospheric plasma irregularities in both high‐latitude and equatorial regions, we analyzed the long‐term global navigation satellite system (GNSS) total electron content (TEC) data from 2000 to 2018 and performed a superposed epoch analysis of the GNSS rate of the TEC inde...
Space weather adversely affects the satellite systems by obstructing the services of Global Positioning Systems (GPS), delaying the launch of space vehicles, and causing damage to basic infrastructures such as radio-communications and power distribution networks. The spatio-temporal variations of ionospheric Total Electron Content (TEC) during geom...
Satellite based radio communication and navigation systems rely mostly on trans-ionospheric propagation of radio signals concerning changes by total electron content (TEC). Therefore, it is necessary to understand the changing behavior of structural variations of ionospheric TEC for high-frequency applications besides mitigating the risks associate...
Equatorial plasma bubbles are a phenomenon of plasma density depletion with small-scale density irregularities, normally observed in the equatorial ionosphere. This phenomenon, which impacts satellite-based communications, was observed in the Asia-Pacific region after the largest-on-record January 15, 2022 eruption of the Tonga volcano. We used sat...
To elucidate the characteristics of electromagnetic conjugacy of traveling ionospheric disturbances just after the 15 January 2022 Hunga Tonga-Hunga Ha’apai volcanic eruption, we analyze Global Navigation Satellite System-total electron content data and ionospheric plasma velocity data obtained from the Super Dual Auroral Radar Network Hokkaido pai...
This study, for the first time, reports the geomagnetically conjugate structure of a plasma bubble extending to the mid-latitudes and the asymmetrical structure of the decay of the plasma bubble during a geomagnetic storm. We investigated the temporal and spatial variations of plasma bubbles in the Asian sector during a geomagnetic storm on March 1...
The occurrence of post-sunset equatorial spread-F (ESF) could have detrimental effects on trans-ionospheric radio wave propagation used in modern communications systems. This problem calls for a simple but robust model that accurately predicts the occurrence of post-sunset ESF. Logistic regression was implemented to model the daily occurrence of po...
We conduct a statistical analysis on nighttime medium‐scale traveling ionospheric disturbances (MSTIDs) using the Super Dual Auroral Radar Network (SuperDARN) Hokkaido East (43.53°N, 143.61°E) high‐frequency (HF) radar data from 2009 to 2019 and the SuperDARN Hokkaido West (43.54°N, 143.61°E) HF radar data from 2016 to 2019. We analyze the line‐of‐...
We applied a novel three‐dimensional spectral analysis method to GPS‐TEC perturbation (GPS‐TECP) maps to study the propagation direction of daytime and nighttime medium‐scale traveling ionospheric disturbances (MSTIDs) over North America. By this method, we can automatically calculate the phase velocity spectrum and directionality of MSTIDs. We foc...
This study presents an analysis of OH airglow images observed from an all‐sky camera (ASC) at King Sejong Station (KSS), Antarctic for the 2012–2016 period. The two‐dimensional power spectra of short‐period gravity waves (<1 hr) as a function of phase velocities are obtained using the M‐transform method that employs the time sequence of ASC images....
Atmospheric gravity waves (AGWs) are among the important energy and momentum transfer mechanisms from the troposphere to the middle and upper atmosphere. Despite their understood importance in governing the structure and dynamics of these regions, mesospheric AGWs remain poorly measured globally, and largely unconstrained in numerical models. Since...
We developed user-friendly software based on Matsuda et al.'s (2014) 3D-FFT
method (Matsuda-transform, M-transform) for airglow imaging data analysis as
a function of Interactive Data Language (IDL). Users can customize the range
of wave parameters to process when executing the program. The input for this
function is a 3-D array of a time series of...
We have developed a user-friendly software based on Matsuda et al. (2014) 3D-FFT method (M-Transform) for airglow imaging data analysis, as a function on Interactive Data Language (IDL), in which users can customize the range of wave parameters to process when executing the program. Input of this function is 3D array of a time series of 2D airglow...
We report a statistical study on concentric gravity waves (CGWs) in the mesopause (~95 km) using 3 years nightglow data obtained by IMAP/VISI. 235 CGWs events were found with horizontal wavelength ranging from 40-250 km and maximum radius of 200-3000 km. The latitudinal distribution of the CGWs centers had peaks in mid latitude (40°N and 40°S) and...
We present a study of concentric gravity waves (CGWs) event from the coordinated observation between IMAP/VISI, all-sky camera at Rikubetsu, MTSAT, TRMM and MF radar at Wakkanai combined with MERRA data. IMAP/VISI is the first space-based imager that capable of imaging the airglow in the mesosphere and lower thermosphere (MLT) region in the nadir-l...
A VHF radar with operating frequency of 30.8 MHz and peak power of 20 kW
has been operated at Kototabang (0.20S, 100.32E; dip latitude 10.4S),
Indonesia since February 2006. From the continuous observation from
February 2006 to August 2011, we find that FAIs appeared frequently at
pre-midnight at equinoxes and at post-midnight between May and Augus...
