Revisiting study of a diurnal variation of atmospheric electric field - Carnegie Curve - observed at Syowa Station

第6回極域科学シンポジウム[OS] 宙空圏11月16日（月）　国立極地研究所１階交流アトリウ

An inspection of geomagnetic field observations at Syowa station, Antarctica

第2回極域科学シンポジウム/第35回極域宙空圏シンポジウム 11月16日（水） 統計数理研究所 3階リフレッシュフロ

地吹雪時の吹雪粒子の帯電と大気電場変動の関係

第6回極域科学シンポジウム[OS] 宙空圏11月16日（月）　国立極地研究所 2階 大会議

ヒガシ オングルトウ ニオケル チジキ ソクリョウ シンキ ニ ケンチク サレタ シセツ ニヨル チジキ カンソク ヘノ エイキョウ ノ ケンショウ

2010年から2011年にかけて,昭和基地では地磁気観測点近傍に大規模な構造物(自然エネルギー棟,大型大気レーダー,コンテナヤードなど)が設置された.これらの施設建設で使用された鉄材は,地磁気観測に対しノイズ源となる可能性がある.昭和基地で建設された大型施設で使用された鉄材が地磁気観測点に与える影響を評価するため,建設前後で昭和基地周辺部において磁気測量を実施した.建設前後の全磁力分布の差から構造物によるノイズを推定した結果,最大で1.0 nT程度の人工ノイズの影響を地磁気観測点が受けている可能性があることが分かった.During 2010 and 2011, some large facilities (e.g. a mechanical workshop, an atmospheric radar and a container yard) were constructed near the geomagnetic observation site at Syowa Station, Antarctica. Iron materials used in these facilities could potentially affect the geomagnetic field at the observation site. To evaluate the amount of artificial magnetic noise caused by the iron materials, we carried out magnetic surveys around Syowa Station before and after construction of the facilities. The results show that the iron materials generate a maximum of 1.0 nT of artificial noise at the geomagnetic observation site

A Study on Variations of Baseline Values of Geomagnetic Field Observations at Syowa Station

第6回極域科学シンポジウム[OS] 宙空圏11月16日（月）　国立極地研究所１階交流アトリウ

Current status of Iceland-Syowa conjugate observation in 2019

The Tenth Symposium on Polar Science/Ordinary sessions: [OS] Space and upper atmospheric sciences, Wed. 4 Dec. / Institute of Statistics and Mathematics (ISM) Seminar room 2 (D304) (3rd floor

Availability and Access to Data from Kakioka Magnetic Observatory, Japan

The Japan Meteorological Agency (JMA) is operating four geomagnetic observatories in Japan. Kakioka Magnetic Observatory (KMO), commissioned in 1913, is the oldest. The hourly records at KMO cover over almost 100 years. KMO is JMA's headquarters for geomagnetic and geoelectric observations. Almost all data are available at the KMO website free of charge for researchers. KMO and two other observatories have been certified as INTERMAGNET observatories, and quasi-real-time geomagnetic data from them are available at the INTERMAGNET website

Origin of the intense positive and moderate negative atmospheric electric field variations measured during and after Antarctic blizzards

There is an atmospheric electric field (AEF) or an electric potential gradient (PG) in fair weather between the Earth's surface and the mesosphere/ionosphere, which is positive. During blizzards/snowstorms in the polar regions, an intense positive AEF/PG in the order of 10(3)V/m of the same polarity in fair weather was observed using an electric field mill at 1.4 m in height. In contrast, a moderately negative AEF/PG variation after a blizzard was observed in 2015 at Syowa Station, Antarctica. The negative variation, where the magnitude ranged from tens to hundreds of V/m, gradually recovered into the positive AEF/PG for more than 40 min. According to various studies on blowing/drifting snow dynamics and electricity in laboratory experiments and field observations, snow particles colliding with the snow surface are charged, and the charge of suspended and saltating particles during the snowstorm is negative on average. To verify the AEF/PG observed during and after the blizzards, we numerically estimated the electric field surrounding the conductive sensor unit of the electric field mill using a three-dimensional Poisson equation. Under blizzard conditions, the polarity of the estimated AEF/PG was the opposite of that of the observed AEF/PG. From the noise study of the field mill, we deduced that the positive AEF/PG variations were caused by the collision of negatively charged snow particles with the electric probe on the sensor unit. Just after the blizzard, the number of snow particles measured at 4.4 m in height clearly decreased, and the camera image showed clear visibility. From this evidence, we modeled the suspended and saltating negatively charged snow particles that had fallen onto the ground surface and then constructed a charge layer of the snow particles softly attaching to the ground, which slowly discharged following the study on the electrical resistance of the powders. The three-dimensional Poisson calculation based on the model reproduced a moderately negative AEF/PG. Thus, we elucidated that the origins of the intense positive and moderate negative electric fields during and after blizzards are the charged snow particles colliding with the electric probe on the sensor unit and the negative snow layers softly attached to the ground, respectively. These results are applicable to studies on dust storm electrification on Mars' and Earth's deserts, snowstorm electrification in the polar regions, and high mountains, such as Mt. Fuji in Japan, and turbulent electrification for industrial dust, which provides the identification of intense electrification and storms