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T Ogawa - One of the best experts on this subject based on the ideXlab platform.
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observation of equatorial nighttime medium scale traveling ionospheric disturbances in 630 nm airglow images over 7 years
Journal of Geophysical Research, 2012Co-Authors: D Fukushima, K Shiokawa, Yuichi Otsuka, T OgawaAbstract:[1] We report on nighttime medium-scale traveling ionospheric disturbances (MSTIDs) observed at Kototabang, Indonesia (geographic longitude: 100.3°E; geographic Latitude: 0.2°S; and Geomagnetic Latitude: 10.6°S) during a 7-year period from October 2002 to October 2009. MSTIDs were observed in 630-nm nighttime airglow images by using a highly sensitive all-sky airglow imager at Kototabang. The averages and standard deviations of horizontal phase velocity, period, and horizontal wavelength of MSTIDs observed during the 7 years were 320 ± 170 m/s, 42 ± 11 min, and 790 ± 440 km, respectively. The occurrence rate of the observed MSTIDs decreased with decreasing solar activity. The average horizontal wavelength of MSTIDs increased with decreasing solar activity. Southward MSTIDs were dominant throughout the 7 years of observations. These facts are consistent with the hypothesis that the observed MSTIDs are caused by gravity waves in the thermosphere. Moreover, we compared the propagation directions of the observed MSTIDs with the locations of tropospheric convection activity for the events where gravity waves producing the observed MSTIDs could have existed in the lower atmosphere. Strong tropospheric convection was found within ±30 degrees from the source directions of MSTIDs in 81% of the MSTID events. In such events, gravity waves were possibly generated from deep convection in the troposphere and directly propagated into the thermosphere.
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motion of polar cap patches a statistical study with all sky airglow imager at resolute bay canada
Journal of Geophysical Research, 2009Co-Authors: K Hosokawa, T Kashimoto, S Suzuki, K Shiokawa, Yuichi Otsuka, T OgawaAbstract:[1] A highly sensitive all-sky airglow imager (part of the Optical Mesosphere Thermosphere Imagers [OMTIs]) has been operating for 3 years at Resolute Bay, Canada (geographic Latitude 74.7°N; Geomagnetic Latitude 82.9°N) since January 2005. One of its major applications is the observation of polar cap patches. Polar cap patches are generated in the vicinity of the cusp during southward interplanetary magnetic field (IMF) conditions, and they exhibit dynamic movement, possibly in association with the changes in the IMF orientation. In order to determine how their motions are controlled by the upstream IMF conditions, we applied a motion-tracking algorithm that was based on two-dimensional cross-correlation analysis to consecutive images obtained from January 2005 to December 2007 by the all-sky airglow imager at Resolute Bay. We identified and extracted 561 individual patches and then carried out a statistical study of their motion. It is demonstrated that the speed of patches is primarily controlled by the IMF Bz. Furthermore, the dawn-dusk component of the patch drift velocities is well correlated with the IMF By, which is in good agreement with the published By dependence of the nightside polar cap convection. This enables us to monitor the plasma convection within the polar cap by using polar cap patches as tracers.
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quasiperiodic southward moving waves in 630 nm airglow images in the equatorial thermosphere
Journal of Geophysical Research, 2006Co-Authors: K Shiokawa, Yuichi Otsuka, T OgawaAbstract:[1] We report quasiperiodic southward moving waves, which are commonly observed in the OI 630-nm airglow images (emission altitudes of 200–300 km) near the equator, in 2-year airglow observations at Kototabang, Indonesia (0.2°S, 100.3°E, Geomagnetic Latitude of −10.4°). The waves have predominantly east-west phase fronts and repeatedly propagate southward with a velocity of 310 ± 110 m/s and a period of 40 ± 15 min. They are frequently observed in May–July with an occurrence rate of 53% and are also observed in other seasons with occurrences of ∼20%. The waves are observed in and to the south (Geomagnetically poleward) of the equatorial ionospheric anomaly, which is identified as an airglow enhancement region moving gradually to lower Geomagnetic Latitudes at the premidnight local times. We suggest that gravity waves in the lower thermosphere below ∼300 km are a plausible cause of the observed quasiperiodic waves in the airglow images.
K Shiokawa - One of the best experts on this subject based on the ideXlab platform.
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observation of equatorial nighttime medium scale traveling ionospheric disturbances in 630 nm airglow images over 7 years
Journal of Geophysical Research, 2012Co-Authors: D Fukushima, K Shiokawa, Yuichi Otsuka, T OgawaAbstract:[1] We report on nighttime medium-scale traveling ionospheric disturbances (MSTIDs) observed at Kototabang, Indonesia (geographic longitude: 100.3°E; geographic Latitude: 0.2°S; and Geomagnetic Latitude: 10.6°S) during a 7-year period from October 2002 to October 2009. MSTIDs were observed in 630-nm nighttime airglow images by using a highly sensitive all-sky airglow imager at Kototabang. The averages and standard deviations of horizontal phase velocity, period, and horizontal wavelength of MSTIDs observed during the 7 years were 320 ± 170 m/s, 42 ± 11 min, and 790 ± 440 km, respectively. The occurrence rate of the observed MSTIDs decreased with decreasing solar activity. The average horizontal wavelength of MSTIDs increased with decreasing solar activity. Southward MSTIDs were dominant throughout the 7 years of observations. These facts are consistent with the hypothesis that the observed MSTIDs are caused by gravity waves in the thermosphere. Moreover, we compared the propagation directions of the observed MSTIDs with the locations of tropospheric convection activity for the events where gravity waves producing the observed MSTIDs could have existed in the lower atmosphere. Strong tropospheric convection was found within ±30 degrees from the source directions of MSTIDs in 81% of the MSTID events. In such events, gravity waves were possibly generated from deep convection in the troposphere and directly propagated into the thermosphere.
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on post midnight field aligned irregularities observed with a 30 8 mhz radar at a low Latitude comparison withf layer altitude near the Geomagnetic equator
Journal of Geophysical Research, 2012Co-Authors: Michi Nishioka, K Shiokawa, Yuichi Otsuka, Takuya Tsugawa, Pornchai Supnithi, Tsutomu Nagatsuma, Ken T MurataAbstract:[1] We investigated the relationship between post-midnightF-region field aligned irregularities (FAIs) andF-layer altitude by analyzing data of a 30.8-MHz radar installed 5at Kototabang, Indonesia (0.2°S, 100.3°E; Geomagnetic Latitude 10.4°S) and an ionosonde installed at Chumphon, Thailand (10.7°N, 99.4°E; Geomagnetic Latitude 3.3°N). Chumphon is located near the Geomagnetic equator on approximately the same meridian as Kototabang. Case studies show that the altitude of theF-layer rose at Chumphon a half hour before the post-midnight FAIs appeared at Kototabang. The Doppler velocity of theE-region FAIs observed simultaneously by the 30.8-MHz radar was downward, indicating that theF-layer uplift was not caused by the electric field. We also investigated seasonal variations of the post-midnight FAI occurrence and theF-layer altitude. Both the post-midnight FAIs and the uplift of theF-layer were frequently seen around midnight between May and August. The seasonal variation of the midnightF-layer uplift around the Geomagnetic equator coincided with that of the post-midnight FAI occurrence at Kototabang. These results suggest that the uplift of theF-layer would play an important role in the generation of post-midnight FAIs. We evaluated the linear growth rate of the Rayleigh-Taylor instability based on the altitude of theF-layer observed at Chumphon. The result shows that the uplift of theF-layer can enhance the growth rate because gravity-driven eastward electric current increases. Therefore, we interpret that the observed FAIs were accompanied by plasma bubble, the growth rate of which was reinforced by the upliftedF-layer.
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rayleigh taylor type instability in auroral patches
Journal of Geophysical Research, 2010Co-Authors: K Shiokawa, A Nakajima, A Ieda, Kaori Sakaguchi, R Nomura, T Aslaksen, M Greffen, E DonovanAbstract:[1] Based on observations by a high-resolution narrow field-of-view CCD camera, we found small-scale (5–25 km) finger-like structures at the western boundary of auroral patches in images obtained at Gillam (Geomagnetic Latitude: 65.5°N), Canada, in January 2008. Since shear motion was not observed along the boundary of the patches, we suggest that these structures are formed by macroscopic Rayleigh-Taylor type plasma instability arising in the magnetospheric equatorial plane from the force balancing of the (eastward) magnetic tension force and the (westward) pressure gradient force.
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motion of polar cap patches a statistical study with all sky airglow imager at resolute bay canada
Journal of Geophysical Research, 2009Co-Authors: K Hosokawa, T Kashimoto, S Suzuki, K Shiokawa, Yuichi Otsuka, T OgawaAbstract:[1] A highly sensitive all-sky airglow imager (part of the Optical Mesosphere Thermosphere Imagers [OMTIs]) has been operating for 3 years at Resolute Bay, Canada (geographic Latitude 74.7°N; Geomagnetic Latitude 82.9°N) since January 2005. One of its major applications is the observation of polar cap patches. Polar cap patches are generated in the vicinity of the cusp during southward interplanetary magnetic field (IMF) conditions, and they exhibit dynamic movement, possibly in association with the changes in the IMF orientation. In order to determine how their motions are controlled by the upstream IMF conditions, we applied a motion-tracking algorithm that was based on two-dimensional cross-correlation analysis to consecutive images obtained from January 2005 to December 2007 by the all-sky airglow imager at Resolute Bay. We identified and extracted 561 individual patches and then carried out a statistical study of their motion. It is demonstrated that the speed of patches is primarily controlled by the IMF Bz. Furthermore, the dawn-dusk component of the patch drift velocities is well correlated with the IMF By, which is in good agreement with the published By dependence of the nightside polar cap convection. This enables us to monitor the plasma convection within the polar cap by using polar cap patches as tracers.
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quasiperiodic southward moving waves in 630 nm airglow images in the equatorial thermosphere
Journal of Geophysical Research, 2006Co-Authors: K Shiokawa, Yuichi Otsuka, T OgawaAbstract:[1] We report quasiperiodic southward moving waves, which are commonly observed in the OI 630-nm airglow images (emission altitudes of 200–300 km) near the equator, in 2-year airglow observations at Kototabang, Indonesia (0.2°S, 100.3°E, Geomagnetic Latitude of −10.4°). The waves have predominantly east-west phase fronts and repeatedly propagate southward with a velocity of 310 ± 110 m/s and a period of 40 ± 15 min. They are frequently observed in May–July with an occurrence rate of 53% and are also observed in other seasons with occurrences of ∼20%. The waves are observed in and to the south (Geomagnetically poleward) of the equatorial ionospheric anomaly, which is identified as an airglow enhancement region moving gradually to lower Geomagnetic Latitudes at the premidnight local times. We suggest that gravity waves in the lower thermosphere below ∼300 km are a plausible cause of the observed quasiperiodic waves in the airglow images.
Yuichi Otsuka - One of the best experts on this subject based on the ideXlab platform.
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Temporal and Spatial Variations of Mid-Latitude Ionospheric Trough During a Geomagnetic Storm Based on Global GNSS-TEC and Arase Satellite Observations
2018 2nd URSI Atlantic Radio Science Meeting (AT-RASC), 2018Co-Authors: Atsuki Shinbori, Yuichi Otsuka, Michi Nishioka, Takuya Tsugawa, Atsushi Kumamoto, Fuminori Tsuchia, Shoya Matsuda, Yoshiya KasaharaAbstract:The Earth's plasmasphere is the vast `doughnut' shaped dense plasma region of the magnetosphere that is filled with cold ions and electrons of ionospheric origin. The plasmaspheric plasma density shows an abrupt drop by a factor of 5 or more around 4-6 Re (Re: Earth's radius). The boundary has been called `plasmapause'. Since the plasmaspheric cold plasma controls generation of plasma waves, their propagation features, and particle acceleration via wave-particle interaction, detailed investigation of the temporal and spatial variations of the plasmasphere and plasmapause location during a Geomagnetic storm is important for understanding a change in plasma wave environments in the inner magnetosphere. Recent studies showed a good correlation between the mid-Latitude ionospheric trough and the plasmapause for both Geomagnetically quiet and disturbed conditions [1]. However, they did not reach the detailed investigation of the characteristics of spatial variation of the mid-Latitude ionospheric trough and its temporal variation with high resolution due to limitation of a usage of global GIM of TEC. In this study, we investigate characteristics of temporal and spatial variations of the mid-Latitude ionospheric trough during a Geomagnetic storm which occurred on April 4, 2017 using the 5-min average Global Navigation Satellite System (GNSS) Total Electron Content (TEC) data together with solar wind, interplanetary magnetic field, Geomagnetic field, and Arase High Frequency Analyzer (HFA) (subcomponent of Plasma Wave Experiment (PWE)) observation data. As a result, the location of the mid-Latitude ionospheric trough moves equatorward from 60 to 48 degrees within 4 hours after the onset of the storm main phase. The movement speed increases from 1.3 to 3.5 degrees of Geomagnetic Latitude per hour after the onset of storm-time substorm. The increasing speed means an abrupt shrink of the plasmasphere due to a sudden enhancement of convection electric field in the inner magnetosphere associated with the substorm onset. The location of the mid-Latitude ionospheric trough identified from the minimum value of the GNSS-TEC data from the auroral to mid-Latitude regions is almost in good agreement with that of an abrupt drop of electron density derived from the upper limit frequency of the upper hybrid resonance (UHR) waves detected by the HFA instrument onboard the Arase satellite. In this case, the electron density profile along the Arase orbit shows an irregular variation of the electron density near the plasmapause. During the main phase of the Geomagnetic storm, the Geomagnetic longitude distribution of the mid-Latitude trough location shows a wavy structure with its scale of 1000-2500 km. The shape of the wavy structure varies with time during the storm main phase. This phenomenon has not yet been reported before due to the limitation of ground dense GNSS receiver networks. After the start of the recovery phase of the Geomagnetic storm, the mid-Latitude ionospheric trough quickly moves poleward from 48 to 60 degrees in Geomagnetic Latitude within 4 hours in a Geomagnetic longitude range of 310-360 degrees in Geomagnetic longitude. The average speed of the poleward movement is 2.3 degrees of Geomagnetic Latitude per hour.
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observation of equatorial nighttime medium scale traveling ionospheric disturbances in 630 nm airglow images over 7 years
Journal of Geophysical Research, 2012Co-Authors: D Fukushima, K Shiokawa, Yuichi Otsuka, T OgawaAbstract:[1] We report on nighttime medium-scale traveling ionospheric disturbances (MSTIDs) observed at Kototabang, Indonesia (geographic longitude: 100.3°E; geographic Latitude: 0.2°S; and Geomagnetic Latitude: 10.6°S) during a 7-year period from October 2002 to October 2009. MSTIDs were observed in 630-nm nighttime airglow images by using a highly sensitive all-sky airglow imager at Kototabang. The averages and standard deviations of horizontal phase velocity, period, and horizontal wavelength of MSTIDs observed during the 7 years were 320 ± 170 m/s, 42 ± 11 min, and 790 ± 440 km, respectively. The occurrence rate of the observed MSTIDs decreased with decreasing solar activity. The average horizontal wavelength of MSTIDs increased with decreasing solar activity. Southward MSTIDs were dominant throughout the 7 years of observations. These facts are consistent with the hypothesis that the observed MSTIDs are caused by gravity waves in the thermosphere. Moreover, we compared the propagation directions of the observed MSTIDs with the locations of tropospheric convection activity for the events where gravity waves producing the observed MSTIDs could have existed in the lower atmosphere. Strong tropospheric convection was found within ±30 degrees from the source directions of MSTIDs in 81% of the MSTID events. In such events, gravity waves were possibly generated from deep convection in the troposphere and directly propagated into the thermosphere.
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on post midnight field aligned irregularities observed with a 30 8 mhz radar at a low Latitude comparison withf layer altitude near the Geomagnetic equator
Journal of Geophysical Research, 2012Co-Authors: Michi Nishioka, K Shiokawa, Yuichi Otsuka, Takuya Tsugawa, Pornchai Supnithi, Tsutomu Nagatsuma, Ken T MurataAbstract:[1] We investigated the relationship between post-midnightF-region field aligned irregularities (FAIs) andF-layer altitude by analyzing data of a 30.8-MHz radar installed 5at Kototabang, Indonesia (0.2°S, 100.3°E; Geomagnetic Latitude 10.4°S) and an ionosonde installed at Chumphon, Thailand (10.7°N, 99.4°E; Geomagnetic Latitude 3.3°N). Chumphon is located near the Geomagnetic equator on approximately the same meridian as Kototabang. Case studies show that the altitude of theF-layer rose at Chumphon a half hour before the post-midnight FAIs appeared at Kototabang. The Doppler velocity of theE-region FAIs observed simultaneously by the 30.8-MHz radar was downward, indicating that theF-layer uplift was not caused by the electric field. We also investigated seasonal variations of the post-midnight FAI occurrence and theF-layer altitude. Both the post-midnight FAIs and the uplift of theF-layer were frequently seen around midnight between May and August. The seasonal variation of the midnightF-layer uplift around the Geomagnetic equator coincided with that of the post-midnight FAI occurrence at Kototabang. These results suggest that the uplift of theF-layer would play an important role in the generation of post-midnight FAIs. We evaluated the linear growth rate of the Rayleigh-Taylor instability based on the altitude of theF-layer observed at Chumphon. The result shows that the uplift of theF-layer can enhance the growth rate because gravity-driven eastward electric current increases. Therefore, we interpret that the observed FAIs were accompanied by plasma bubble, the growth rate of which was reinforced by the upliftedF-layer.
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motion of polar cap patches a statistical study with all sky airglow imager at resolute bay canada
Journal of Geophysical Research, 2009Co-Authors: K Hosokawa, T Kashimoto, S Suzuki, K Shiokawa, Yuichi Otsuka, T OgawaAbstract:[1] A highly sensitive all-sky airglow imager (part of the Optical Mesosphere Thermosphere Imagers [OMTIs]) has been operating for 3 years at Resolute Bay, Canada (geographic Latitude 74.7°N; Geomagnetic Latitude 82.9°N) since January 2005. One of its major applications is the observation of polar cap patches. Polar cap patches are generated in the vicinity of the cusp during southward interplanetary magnetic field (IMF) conditions, and they exhibit dynamic movement, possibly in association with the changes in the IMF orientation. In order to determine how their motions are controlled by the upstream IMF conditions, we applied a motion-tracking algorithm that was based on two-dimensional cross-correlation analysis to consecutive images obtained from January 2005 to December 2007 by the all-sky airglow imager at Resolute Bay. We identified and extracted 561 individual patches and then carried out a statistical study of their motion. It is demonstrated that the speed of patches is primarily controlled by the IMF Bz. Furthermore, the dawn-dusk component of the patch drift velocities is well correlated with the IMF By, which is in good agreement with the published By dependence of the nightside polar cap convection. This enables us to monitor the plasma convection within the polar cap by using polar cap patches as tracers.
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quasiperiodic southward moving waves in 630 nm airglow images in the equatorial thermosphere
Journal of Geophysical Research, 2006Co-Authors: K Shiokawa, Yuichi Otsuka, T OgawaAbstract:[1] We report quasiperiodic southward moving waves, which are commonly observed in the OI 630-nm airglow images (emission altitudes of 200–300 km) near the equator, in 2-year airglow observations at Kototabang, Indonesia (0.2°S, 100.3°E, Geomagnetic Latitude of −10.4°). The waves have predominantly east-west phase fronts and repeatedly propagate southward with a velocity of 310 ± 110 m/s and a period of 40 ± 15 min. They are frequently observed in May–July with an occurrence rate of 53% and are also observed in other seasons with occurrences of ∼20%. The waves are observed in and to the south (Geomagnetically poleward) of the equatorial ionospheric anomaly, which is identified as an airglow enhancement region moving gradually to lower Geomagnetic Latitudes at the premidnight local times. We suggest that gravity waves in the lower thermosphere below ∼300 km are a plausible cause of the observed quasiperiodic waves in the airglow images.
K G Mccracken - One of the best experts on this subject based on the ideXlab platform.
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research by the tasmanian cosmic ray group during the international geophysical year
Advances in Space Research, 2009Co-Authors: K G Mccracken, J E Humble, M L DuldigAbstract:Abstract Systematic recording of the cosmic radiation commenced in Hobart in 1946 and at Mawson in Antarctica in 1955, making these two of the longest running cosmic ray observatories in the world. For the IGY, observations were also made at a sub-Antarctic island and near the equator, and an airborne survey of the nucleonic component was made from Geomagnetic Latitude −60°, south of Australia, to Japan and back. At Hobart there were neutron monitors, vertical and inclined muon telescopes, an ionization chamber, and two muon telescopes at ∼40 m of water equivalent underground. The research based on these and other observations determined the energy dependence of the Forbush and 11-year variations and concentrated, in particular, on understanding the anisotropic nature of galactic cosmic rays up to 150 GeV; the anisotropies in the onset phase of Forbush decreases; and the anisotropies in solar cosmic ray events. An investigation was initiated to calculate the trajectories and cutoff rigidities of cosmic rays in a high order simulation of the Geomagnetic field. This was completed in 1959–60.
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production of the cosmogenic isotopes 3h 7be 10be and 36cl in the earth s atmosphere by solar and galactic cosmic rays
Journal of Geophysical Research, 2007Co-Authors: W R Webber, P R Higbie, K G MccrackenAbstract:[1] In a follow-up study to the earlier work of Webber and Higbie (2003) on 10Be production in the Earth's atmosphere by cosmic rays, we have calculated the atmospheric production of the cosmogenic isotopes 3H, 7Be, 10Be, and 36Cl using the FLUKA Monte Carlo code. This new calculation of atmospheric yields of these isotopes is based on 107 vertically incident protons at each of 24 logarithmically spaced energies from 10 MeV to 10 GeV, 102 times the number used in the earlier calculation, along with the latest cross sections. This permits a study of the production due to solar cosmic rays as well as galactic cosmic rays at lower energies where isotope production is a very sensitive function of energy. Solar cosmic ray spectra are reevaluated for all of the major events occurring since 1956. In terms of yearly production of 10Be, only the February 1956 solar event makes a major contribution. For 36Cl these yearly SCR production contributions are 2–5 times larger depending on the solar cosmic ray energy spectra. We have determined the yearly production of 10Be, 36Cl, and other cosmogenic isotopes above 65° Geomagnetic Latitude for the time period 1940–2006 covering six solar 11-year (a) cycles. The average peak-to-peak 11-a amplitude of this yearly production is 1.77. The effects of latitudinal mixing alter these direct polar production values considerably, giving an average peak-to-peak 11-a amplitude of 1.48 for the global average production.
Nitinkumar Bijewar - One of the best experts on this subject based on the ideXlab platform.
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low energy secondary cosmic ray flux gamma rays monitoring and its constrains
Astrophysics and Space Science, 2015Co-Authors: Anil Raghav, Ankush Bhaskar, Virendra Yadav, Nitinkumar BijewarAbstract:Temporal variation of secondary cosmic rays (SCR) flux was measured during the full and new moon and days close to them at Department of Physics, University of Mumbai, Mumbai (Geomagnetic Latitude: 10.6 °N), India. The measurements were done by using NaI (Tl) scintillation detector with energy threshold of 200 keV. The SCR flux showed sudden enhancement for approximately about 2 hour during few days out of all observations. The maximum enhancement in SCR flux is about 200 % as compared to the diurnal trend of SCR temporal variations. Weather parameters (temperature and relative humidity) were continuously monitored during all observations. The influences of Geomagnetic field, interplanetary parameters and tidal effect on SCR flux have been considered. Summed spectra corresponding to enhancement duration indicates appearance of atmospheric radioactivity which shows single gamma ray line. Detail investigation revealed the presence of radioactive Ar41. Present study indicates origin of Ar41 could be due to anthropogenic source or due to gravitational tidal forces. This measurements point out limitations on low energy SCR flux monitoring. This study will help many researchers in measurements of SCR flux during eclipses and to find unknown mechanism behind decrease/increase in SCR flux during solar/lunar eclipse.
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low energy secondary cosmic ray flux gamma rays monitoring and its constrains
arXiv: Earth and Planetary Astrophysics, 2014Co-Authors: Anil Raghav, Ankush Bhaskar, Virendra Yadav, Nitinkumar BijewarAbstract:Temporal variation of secondary cosmic rays (SCR) flux was measured during the several full and new moon and days close to them at Department of Physics, University of Mumbai, Mumbai (Geomagnetic Latitude: 10.6 N), India. The measurements were done by using NaI (Tl) scintillation detector with energy threshold of 200 keV. The SCR flux shows sudden enhancement for approximately about 2 hour in counts during couple of events out of all experimental observations. The maximum Enhancement SCR flux is about 200% as compared to the diurnal trend of SCR temporal variations. Weather parameters (temperature and relative humidity) were continuously monitored during all observation. The influences of Geomagnetic field, interplanetary parameters and tidal effect on SCR flux have been considered. Summed spectra corresponding to enhancement duration indicates appearance of atmospheric radioactivity which shows single gamma ray line. Detail investigation revealed the presence of radioactive Ar 41 . This measurements puts limitations on low energy SCR flux monitoring. This paper will help many researcher who want to measure SCR flux during eclipses and motivate to find unknown mechanism behind decrease/ increase during solar/lunar eclipse.