Pub Date : 2020-06-01DOI: 10.5140/JASS.2020.37.2.95
Hee-Eun Kim, Ensang Lee
Properties of plasmas that constitute the plasma sheet in the near-Earth magnetotail vary according to the solar wind conditions and location in the tail. In this case study, we present multi-spacecraft observations by Cluster that show a transition of plasma sheet from cold, dense to hot, tenuous state. The transition was associated with the passage of a spatial boundary that separates the plasma sheet into two regions with cold, dense and hot, tenuous plasmas. Ion phase space distributions show that the cold, dense ions have a Kappa distribution while the hot, tenuous ions have a Maxwellian distribution, implying that they have different origins or are produced by different thermalization processes. The transition boundary separated the plasma sheet in the dawn-dusk direction, and slowly moved toward the dawn flank. The hot, tenuous plasmas filled the central region while the cold, dense plasmas filled the outer region. The hot, tenuous plasmas were moving toward the Earth, pushing the cold, dense plasmas toward the flank. Different types of dynamical processes can be generated in each region, which can affect the development of geomagnetic activities.
{"title":"Observation of Transition Boundary between Cold, Dense and Hot, Tenuous Plasmas in\u0000 the Near-Earth Magnetotail","authors":"Hee-Eun Kim, Ensang Lee","doi":"10.5140/JASS.2020.37.2.95","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.2.95","url":null,"abstract":"Properties of plasmas that constitute the plasma sheet in the near-Earth\u0000 magnetotail vary according to the solar wind conditions and location in the tail. In\u0000 this case study, we present multi-spacecraft observations by Cluster that show a\u0000 transition of plasma sheet from cold, dense to hot, tenuous state. The transition was\u0000 associated with the passage of a spatial boundary that separates the plasma sheet into\u0000 two regions with cold, dense and hot, tenuous plasmas. Ion phase space distributions\u0000 show that the cold, dense ions have a Kappa distribution while the hot, tenuous ions\u0000 have a Maxwellian distribution, implying that they have different origins or are\u0000 produced by different thermalization processes. The transition boundary separated the\u0000 plasma sheet in the dawn-dusk direction, and slowly moved toward the dawn flank. The\u0000 hot, tenuous plasmas filled the central region while the cold, dense plasmas filled the\u0000 outer region. The hot, tenuous plasmas were moving toward the Earth, pushing the cold,\u0000 dense plasmas toward the flank. Different types of dynamical processes can be generated\u0000 in each region, which can affect the development of geomagnetic activities.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"94 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83873399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.5140/JASS.2020.37.1.1
E. H. Khattab, M. Radwan, W. A. Rahoma
Frozen orbit is an attractive option for orbital design owing to its characteristics (its argument of pericenter and eccentricity are kept constant on an average). Solar sails are attractive solutions for massive and expensive missions. However, the solar radiation pressure effect represents an additional force on the solar sail that may greatly affect its orbital behavior in the long run. Thus, this force must be included as a perturbation force in the dynamical model for more accuracy. This study shows the calculations of initial conditions for a lunar solar sail frozen orbit. The disturbing function of the problem was developed to include the lunar gravitational field that is characterized by uneven mass distribution, third body perturbation, and the effect of solar radiation. An averaging technique was used to reduce the dynamical problem to a long period system. Lagrange planetary equations were utilized to formulate the rate of change of the argument of pericenter and eccentricity. Using the reduced system, frozen orbits for the Moon sail orbiter were constructed. The resulting frozen orbits are shown by two 3Dsurface (semimajor, eccentricity, inclination) figures. To simplify the analysis, we showed inclination–eccentricity contours for different values of semi-major axis, argument of pericenter, and values of sail lightness number.
{"title":"Frozen Orbits Construction for a Lunar Solar Sail","authors":"E. H. Khattab, M. Radwan, W. A. Rahoma","doi":"10.5140/JASS.2020.37.1.1","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.1.1","url":null,"abstract":"Frozen orbit is an attractive option for orbital design owing to its\u0000 characteristics (its argument of pericenter and eccentricity are kept constant on an\u0000 average). Solar sails are attractive solutions for massive and expensive missions.\u0000 However, the solar radiation pressure effect represents an additional force on the solar\u0000 sail that may greatly affect its orbital behavior in the long run. Thus, this force must\u0000 be included as a perturbation force in the dynamical model for more accuracy. This study\u0000 shows the calculations of initial conditions for a lunar solar sail frozen orbit. The\u0000 disturbing function of the problem was developed to include the lunar gravitational\u0000 field that is characterized by uneven mass distribution, third body perturbation, and\u0000 the effect of solar radiation. An averaging technique was used to reduce the dynamical\u0000 problem to a long period system. Lagrange planetary equations were utilized to formulate\u0000 the rate of change of the argument of pericenter and eccentricity. Using the reduced\u0000 system, frozen orbits for the Moon sail orbiter were constructed. The resulting frozen\u0000 orbits are shown by two 3Dsurface (semimajor, eccentricity, inclination) figures. To\u0000 simplify the analysis, we showed inclination–eccentricity contours for different values\u0000 of semi-major axis, argument of pericenter, and values of sail lightness number.\u0000","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"8 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84564439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.5140/JASS.2020.37.1.11
H. Lim, J. Park, Mansoo Choi, C. Choi, J. Choi, Jongah Kim
Satellite optical communication has gained significant attention owing to its many quality features (e.g., a larger bandwidth, license free spectrum, higher data rate, and better security) compared to satellite microwave communication. Various experiments have been performed during many space missions to demonstrate and characterize inter-satellite links, downlinks, and uplinks. Korea has also planned to establish an experimental communication system using a geostationary earth orbit (GEO) satellite and the Geochang station as an optical ground station for low Earth orbit (LEO)-to-ground optical relay links. In this study, the performance of inter-satellite communication links and downlinks was investigated for the new Korean experimental communication system in terms of link margin, bit error rate (BER), and channel capacity. In particular, the performance of the inter-satellite links was analyzed based on the receiving apertures and the transmitting power, while that of the downlink was analyzed in terms of atmospheric turbulence conditions and transmitting power. Finally, we discussed two system parameters of receiving aperture and transmitting power to meet the three criteria of link margin, BER, and channel capacity.
{"title":"Performance Analysis of DPSK Optical Communication for LEO-to-Ground Relay Link Via\u0000 a GEO Satellite","authors":"H. Lim, J. Park, Mansoo Choi, C. Choi, J. Choi, Jongah Kim","doi":"10.5140/JASS.2020.37.1.11","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.1.11","url":null,"abstract":"Satellite optical communication has gained significant attention owing to its\u0000 many quality features (e.g., a larger bandwidth, license free spectrum, higher data\u0000 rate, and better security) compared to satellite microwave communication. Various\u0000 experiments have been performed during many space missions to demonstrate and\u0000 characterize inter-satellite links, downlinks, and uplinks. Korea has also planned to\u0000 establish an experimental communication system using a geostationary earth orbit (GEO)\u0000 satellite and the Geochang station as an optical ground station for low Earth orbit\u0000 (LEO)-to-ground optical relay links. In this study, the performance of inter-satellite\u0000 communication links and downlinks was investigated for the new Korean experimental\u0000 communication system in terms of link margin, bit error rate (BER), and channel\u0000 capacity. In particular, the performance of the inter-satellite links was analyzed based\u0000 on the receiving apertures and the transmitting power, while that of the downlink was\u0000 analyzed in terms of atmospheric turbulence conditions and transmitting power. Finally,\u0000 we discussed two system parameters of receiving aperture and transmitting power to meet\u0000 the three criteria of link margin, BER, and channel capacity.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"3 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73200294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.5140/JASS.2020.37.1.51
Seok Ju Kang, Youngbum Song, Sang-Young Park
This study designs and analyzes satellite formation flying concepts for the Small scale magNetospheric and Ionospheric Plasma Experiments (SNIPE) mission, that will observe the near-Earth space environment using four nanosats. To meet the requirements to achieve the scientific objectives of the SNIPE mission, three formation flying concepts are analyzed: a crossshape formation, a square-shape formation, and a cross-track formation. Of the three formation flying scenarios, the crosstrack formation scenario is selected as the final scenario for the SNIPE mission. The result of this study suggests a relative orbit control scenario for formation maintenance and reconfiguration, and the initial relative orbits of the four nanosats meeting the formation requirements and thrust limitations of the SNIPE mission. The formation flying scenario is validated by calculating the accumulated total thrust required for the four nanosats. If the cross-track formation scenario presented in this study is applied to the SNIPE mission, it is expected that the mission will be successfully accomplished.
{"title":"Nanosat Formation Flying Design for SNIPE Mission","authors":"Seok Ju Kang, Youngbum Song, Sang-Young Park","doi":"10.5140/JASS.2020.37.1.51","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.1.51","url":null,"abstract":"This study designs and analyzes satellite formation flying concepts for the Small\u0000 scale magNetospheric and Ionospheric Plasma Experiments (SNIPE) mission, that will\u0000 observe the near-Earth space environment using four nanosats. To meet the requirements\u0000 to achieve the scientific objectives of the SNIPE mission, three formation flying\u0000 concepts are analyzed: a crossshape formation, a square-shape formation, and a\u0000 cross-track formation. Of the three formation flying scenarios, the crosstrack formation\u0000 scenario is selected as the final scenario for the SNIPE mission. The result of this\u0000 study suggests a relative orbit control scenario for formation maintenance and\u0000 reconfiguration, and the initial relative orbits of the four nanosats meeting the\u0000 formation requirements and thrust limitations of the SNIPE mission. The formation flying\u0000 scenario is validated by calculating the accumulated total thrust required for the four\u0000 nanosats. If the cross-track formation scenario presented in this study is applied to\u0000 the SNIPE mission, it is expected that the mission will be successfully accomplished.\u0000","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"106 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87830582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.5140/JASS.2020.37.1.29
Fayrouz Hussien, E. Ghamry, A. Fathy, S. Mahrous
On 21 August 2017, during 16:49 UT and 20:02 UT period, a total solar eclipse started. The totality shadow occurred over the United States in time between ~17:15 UT and ~18:47 UT. When the solar radiation is blocked by the moon, observations of the ionospheric parameters will be important in the space weather community. Fortunately, during this eclipse, two Swarm satellites (A and C) flied at about 445 km through lunar penumbra at local noon of United States in the upper ionosphere. In this work, we investigate the effect of the solar eclipse on electron density, slant total electron content (STEC) and electron temperature using data from Swarm mission over United States. We use calibrated measurements of plasma density and electron temperature. Our results indicate that: (1) the electron density and STEC have a significant depletion associated with the eclipse; which could be due to dominance of dissociative recombination over photoionization caused by the reduction of ionizing extreme ultraviolet (EUV) radiation during the eclipse time (2) the electron temperature decreases, compared with a reference day, by up to ~150 K; which could be due to the decrease in photoelectron heating from reduced photoionization.
{"title":"Swarm Satellite Observations of the 21 August 2017 Solar Eclipse","authors":"Fayrouz Hussien, E. Ghamry, A. Fathy, S. Mahrous","doi":"10.5140/JASS.2020.37.1.29","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.1.29","url":null,"abstract":"On 21 August 2017, during 16:49 UT and 20:02 UT period, a total solar eclipse\u0000 started. The totality shadow occurred over the United States in time between ~17:15 UT\u0000 and ~18:47 UT. When the solar radiation is blocked by the moon, observations of the\u0000 ionospheric parameters will be important in the space weather community. Fortunately,\u0000 during this eclipse, two Swarm satellites (A and C) flied at about 445 km through lunar\u0000 penumbra at local noon of United States in the upper ionosphere. In this work, we\u0000 investigate the effect of the solar eclipse on electron density, slant total electron\u0000 content (STEC) and electron temperature using data from Swarm mission over United\u0000 States. We use calibrated measurements of plasma density and electron temperature. Our\u0000 results indicate that: (1) the electron density and STEC have a significant depletion\u0000 associated with the eclipse; which could be due to dominance of dissociative\u0000 recombination over photoionization caused by the reduction of ionizing extreme\u0000 ultraviolet (EUV) radiation during the eclipse time (2) the electron temperature\u0000 decreases, compared with a reference day, by up to ~150 K; which could be due to the\u0000 decrease in photoelectron heating from reduced photoionization.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"129 1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77880985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.5140/JASS.2020.37.1.19
Jiwoo Kim, J. Hwang, Hyangpyo Kim, Y. Yi
Pc1 pulsations are important to consider for the interpretation of wave-particle interactions in the Earth’s magnetosphere. In fact, the wave properties of these pulsations change dynamically when they propagate from the source region in the space to the ground. A detailed study of the wave features can help understanding their time evolution mechanisms. In this study, we statistically analyzed Pc1 pulsations observed by a Bohyunsan (BOH) magneto-impedance (MI) sensor located in Korea (L = 1.3) for ~one solar cycle (November 2009-August 2018). In particular, we investigated the temporal occurrence ratio of Pc1 pulsations (considering seasonal, diurnal, and annual variations in the solar cycle), their wave properties (e.g., duration, peak frequency, and bandwidth), and their relationship with geomagnetic activities by considering the Kp and Dst indices in correspondence of the Pc1 pulsation events. We found that the Pc1 waves frequently occurred in March in the dawn (1-3 magnetic local time (MLT)) sector, during the declining phase of the solar cycle. They generally continued for 2-5 minutes, reaching a peak frequency of ~0.9 Hz. Finally, most of the pulsations have strong dependence on the geomagnetic storm and observed during the early recovery phase of the geomagnetic storm.
{"title":"Statistical Analysis of Pc1 Pulsations Observed by a BOH Magnetometer","authors":"Jiwoo Kim, J. Hwang, Hyangpyo Kim, Y. Yi","doi":"10.5140/JASS.2020.37.1.19","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.1.19","url":null,"abstract":"Pc1 pulsations are important to consider for the interpretation of wave-particle\u0000 interactions in the Earth’s magnetosphere. In fact, the wave properties of these\u0000 pulsations change dynamically when they propagate from the source region in the space to\u0000 the ground. A detailed study of the wave features can help understanding their time\u0000 evolution mechanisms. In this study, we statistically analyzed Pc1 pulsations observed\u0000 by a Bohyunsan (BOH) magneto-impedance (MI) sensor located in Korea (L = 1.3) for ~one\u0000 solar cycle (November 2009-August 2018). In particular, we investigated the temporal\u0000 occurrence ratio of Pc1 pulsations (considering seasonal, diurnal, and annual variations\u0000 in the solar cycle), their wave properties (e.g., duration, peak frequency, and\u0000 bandwidth), and their relationship with geomagnetic activities by considering the Kp and\u0000 Dst indices in correspondence of the Pc1 pulsation events. We found that the Pc1 waves\u0000 frequently occurred in March in the dawn (1-3 magnetic local time (MLT)) sector, during\u0000 the declining phase of the solar cycle. They generally continued for 2-5 minutes,\u0000 reaching a peak frequency of ~0.9 Hz. Finally, most of the pulsations have strong\u0000 dependence on the geomagnetic storm and observed during the early recovery phase of the\u0000 geomagnetic storm.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90913122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.5140/JASS.2020.37.1.43
Sa-Rah Park, Ho-Cheol Jeon, R. Kim, Jong-Hyeon Kim, Seung-Jin Kim, Junghee Cho, S. Jang
We have developed an algorithm for tracking coronal mass ejection (CME) propagation that allows us to estimate CME speed and its arrival time at Earth. The algorithm may be used either to forecast the CME’s arrival on the day of the forecast or to update the CME tracking information for the next day’s forecast. In our case study, we successfully tracked CME propagation using the algorithm based on g-values of interplanetary scintillation (IPS) observation provided by the Institute for Space- Earth Environmental Research (ISEE). We were able to forecast the arrival time (Δt = 0.30 h) and speed (Δv = 20 km/s) of a CME event on October 2, 2000. From the CME-interplanetary CME (ICME) pairs provided by Cane & Richardson (2003), we selected 50 events to evaluate the algorithm’s forecast capability. Average errors for arrival time and speed were 11.14 h and 310 km/s, respectively. Results demonstrated that g-values obtained continuously from any single station observation were able to be used as a proxy for CME speed. Therefore, our algorithm may give stable daily forecasts of CME position and speed during propagation in the region of 0.2–1 AU using the IPS g-values, even if IPS velocity observations are insufficient. We expect that this algorithm may be widely accepted for use in space weather forecasting in the near future.
{"title":"Development of Forecast Algorithm for Coronal Mass Ejection Speed and Arrival Time\u0000 Based on Propagation Tracking by Interplanetary Scintillation g-Value","authors":"Sa-Rah Park, Ho-Cheol Jeon, R. Kim, Jong-Hyeon Kim, Seung-Jin Kim, Junghee Cho, S. Jang","doi":"10.5140/JASS.2020.37.1.43","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.1.43","url":null,"abstract":"We have developed an algorithm for tracking coronal mass ejection (CME)\u0000 propagation that allows us to estimate CME speed and its arrival time at Earth. The\u0000 algorithm may be used either to forecast the CME’s arrival on the day of the forecast or\u0000 to update the CME tracking information for the next day’s forecast. In our case study,\u0000 we successfully tracked CME propagation using the algorithm based on g-values of\u0000 interplanetary scintillation (IPS) observation provided by the Institute for Space-\u0000 Earth Environmental Research (ISEE). We were able to forecast the arrival time (Δt =\u0000 0.30 h) and speed (Δv = 20 km/s) of a CME event on October 2, 2000. From the\u0000 CME-interplanetary CME (ICME) pairs provided by Cane & Richardson (2003), we\u0000 selected 50 events to evaluate the algorithm’s forecast capability. Average errors for\u0000 arrival time and speed were 11.14 h and 310 km/s, respectively. Results demonstrated\u0000 that g-values obtained continuously from any single station observation were able to be\u0000 used as a proxy for CME speed. Therefore, our algorithm may give stable daily forecasts\u0000 of CME position and speed during propagation in the region of 0.2–1 AU using the IPS\u0000 g-values, even if IPS velocity observations are insufficient. We expect that this\u0000 algorithm may be widely accepted for use in space weather forecasting in the near\u0000 future.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"120 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89370436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.5140/JASS.2020.37.1.35
Cheong R. Choi, K. Dokgo, C. Woo, K. Min
Particle-in-cell simulations were performed to understand the interaction of the solar wind with localized magnetic fields on the sunlit surface of the Moon. The results indicated a mini-magnetosphere was formed which had a thin magnetopause with the thickness of the electron skin depth. It was also found that the solar wind penetrated into the cavity of the magnetosphere intermittently rather than in a steady manner. The solar wind that moved around the magnetosphere was observed to hit the surface of the Moon, implying that it may be the cause of the lunar swirl formation on the surface.
{"title":"Simulation Study of Solar Wind Interaction with Lunar Magnetic Fields","authors":"Cheong R. Choi, K. Dokgo, C. Woo, K. Min","doi":"10.5140/JASS.2020.37.1.35","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.1.35","url":null,"abstract":"Particle-in-cell simulations were performed to understand the interaction of the\u0000 solar wind with localized magnetic fields on the sunlit surface of the Moon. The results\u0000 indicated a mini-magnetosphere was formed which had a thin magnetopause with the\u0000 thickness of the electron skin depth. It was also found that the solar wind penetrated\u0000 into the cavity of the magnetosphere intermittently rather than in a steady manner. The\u0000 solar wind that moved around the magnetosphere was observed to hit the surface of the\u0000 Moon, implying that it may be the cause of the lunar swirl formation on the surface.\u0000","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"8 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78965930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.5140/JASS.2020.37.1.69
Jeong‐Han Kim, G. Jee, Hyesun Choi, Baek‐Min Kim, Seong‐Joong Kim
We analyze the observations of temperature and ozone measured by the Microwave Limb Sounder (MLS) during the period of 2005–2016, to investigate the vertical structures of temperature and ozone in the stratosphere and mesosphere during stratospheric sudden warming (SSW). We compute the height profiles of the correlation coefficients between 55 height levels of MLS temperature anomalies and compare them with the results of Whole Atmosphere Community Climate Model simulations for three major SSWs. We also construct the temperature and ozone anomalies for the events to investigate the changes in the temperature and ozone distributions with height. There seems to always be a relatively weak but broad negative correlation between the temperature anomaly at 10 hPa and temperature anomalies over the entire mesosphere during the period before SSW events. However, this pattern gets stronger in the lower mesosphere but becomes a positive correlation in the upper mesosphere and lower thermosphere after the onset of SSW. We also found that the temperatures from the simulations show a similar trend to the observational results but with smaller variations and the transition height from negative to positive correlation in the mesosphere is much lower in the simulation than in the actual observations.
{"title":"Vertical Structures of Temperature and Ozone Changes in the Stratosphere and\u0000 Mesosphere during Stratospheric Sudden Warmings","authors":"Jeong‐Han Kim, G. Jee, Hyesun Choi, Baek‐Min Kim, Seong‐Joong Kim","doi":"10.5140/JASS.2020.37.1.69","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.1.69","url":null,"abstract":"We analyze the observations of temperature and ozone measured by the Microwave\u0000 Limb Sounder (MLS) during the period of 2005–2016, to investigate the vertical\u0000 structures of temperature and ozone in the stratosphere and mesosphere during\u0000 stratospheric sudden warming (SSW). We compute the height profiles of the correlation\u0000 coefficients between 55 height levels of MLS temperature anomalies and compare them with\u0000 the results of Whole Atmosphere Community Climate Model simulations for three major\u0000 SSWs. We also construct the temperature and ozone anomalies for the events to\u0000 investigate the changes in the temperature and ozone distributions with height. There\u0000 seems to always be a relatively weak but broad negative correlation between the\u0000 temperature anomaly at 10 hPa and temperature anomalies over the entire mesosphere\u0000 during the period before SSW events. However, this pattern gets stronger in the lower\u0000 mesosphere but becomes a positive correlation in the upper mesosphere and lower\u0000 thermosphere after the onset of SSW. We also found that the temperatures from the\u0000 simulations show a similar trend to the observational results but with smaller\u0000 variations and the transition height from negative to positive correlation in the\u0000 mesosphere is much lower in the simulation than in the actual observations.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"7 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80867627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.5140/JASS.2020.37.1.61
Jeong-Yeong Park, Sun Mie Park
Recent studies have suggested that detectable ionospheric disturbances precede earthquakes. In the present study, variations in the vertical total electron content (TEC) for eight earthquakes with magnitudes of M ≥ 5.5 in the western United States were investigated during the solar maximum of 2013–2015 using United States total electron content (US-TEC) data provided by the National Oceanic and Atmospheric Administration. Analyses of 12 earthquakes with magnitudes of 5.0 ≤ M < 5.5 in the same region were also performed. The TEC variations were examined for 40 days, including the times when the earthquakes occurred. The results indicated a correlation between earthquakes with magnitudes of M ≥ 5.0 and ionospheric TEC anomalies. TEC anomalies occurred before 60% of the earthquakes. Additionally, they were more frequently observed for large earthquakes (75%, M ≥ 5.5) than for small earthquakes (50%, 5.5 > M ≥ 5.0). Anomalous increases in the TEC occurred 2–18 days before the earthquakes as an ionospheric precursor, whereas solar and geomagnetic activities were low or moderate.
{"title":"Investigation of Ionospheric Earthquake Precursors Using US-TEC Data during the\u0000 Solar Maximum of 2013–2015","authors":"Jeong-Yeong Park, Sun Mie Park","doi":"10.5140/JASS.2020.37.1.61","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.1.61","url":null,"abstract":"Recent studies have suggested that detectable ionospheric disturbances precede\u0000 earthquakes. In the present study, variations in the vertical total electron content\u0000 (TEC) for eight earthquakes with magnitudes of M ≥ 5.5 in the western United States were\u0000 investigated during the solar maximum of 2013–2015 using United States total electron\u0000 content (US-TEC) data provided by the National Oceanic and Atmospheric Administration.\u0000 Analyses of 12 earthquakes with magnitudes of 5.0 ≤ M < 5.5 in the same region were\u0000 also performed. The TEC variations were examined for 40 days, including the times when\u0000 the earthquakes occurred. The results indicated a correlation between earthquakes with\u0000 magnitudes of M ≥ 5.0 and ionospheric TEC anomalies. TEC anomalies occurred before 60%\u0000 of the earthquakes. Additionally, they were more frequently observed for large\u0000 earthquakes (75%, M ≥ 5.5) than for small earthquakes (50%, 5.5 > M ≥ 5.0). Anomalous\u0000 increases in the TEC occurred 2–18 days before the earthquakes as an ionospheric\u0000 precursor, whereas solar and geomagnetic activities were low or moderate.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"33 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77943706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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