An integrated analysis platform merging SuperDARN data within the THEMIS tool developed by ERG-Science Center (ERG-SC)

The Energization and Radiation in Geospace (ERG) mission seeks to explore the dynamics of the radiation belts in the Earth’s inner magnetosphere with a space-borne probe (ERG satellite) in coordination with related ground observations and simulations/ modeling studies. For this mission, the Science Center of the ERG project (ERG-SC) will provide a useful data analysis platform based on the THEMIS Data Analysis software Suite (TDAS), which has been widely used by researchers in many conjunction studies of the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft and ground data. To import SuperDARN data to this highly useful platform, ERG-SC, in close collaboration with SuperDARN groups, developed the Common Data Format (CDF) design suitable for fitacf data and has prepared an open database of SuperDARN data archived in CDF. ERG-SC has also been developing programs written in Interactive Data Language (IDL) to load fitacf CDF files and to generate various kinds of plots−not only range-time-intensity-type plots but also two-dimensional map plots that can be superposed with other data, such as all-sky images of THEMIS-GBO and orbital footprints of various satellites. The CDF-TDAS scheme developed by ERG-SC will make it easier for researchers who are not familiar with SuperDARN data to access and analyze SuperDARN data and thereby facilitate collaborative studies with satellite data, such as the inner magnetosphere data provided by the ERG (Japan)−RBSP (USA)−THEMIS (USA) fleet

The auroral occurrence over Zhongshan Station, Antarctica

The auroral data observed by all sky TV camera during 1995 and 1997 at Zhongshan Station of Antarctica are used to analyze the statistic characteristics of the aurora over Zhongshan Station. Around post-noon (1200 - 1600 UT) and midnight (2000 - 0100 UT),. The corona type auroras mainly occur at poleward and overhead of Zhongshan Station during post-noon and around midnight. The band type auroras mainly appear during post-noon, while during evening and around midnight only appear at equatorward. The active surges mostly appear around midnight, while the transpolar arcs mainly occur after midnight. Except for the transpolar arcs, the occurrences of the other three type auroras are related with Kþ index. Usually Zhongshan Station enters the auroral oval at post-noon, the exact time depends on Kþ index

Aurora morphology in the dayside

Day-side aurora phenomena are examined by using TV image data obtained at Ny-Alesund in Svalbard, Godhavn in Greenland and Zhongshan Station, Antarctica. Results are summarized as follows. During the quiet period, in the pre- and post-noon sectors. (1) Weak arc (Sun-aligned arc), (2) Corona aurora and (3) Band aurora are observed in these stations. During disturbed period, Corona aurora and Band aurora are also observed in the pre- and post-noon sectors. However, bright discrete aurora, instead of weak arc (Sun-aligned arc), develops from the night side oval in the dawn and dusk sectors. Pre-noon corona and post-noon band aurora are observed in the lower latitude as compared with the location of those auroras during the quiet period

Simultaneous observations of Syowa East HF radar and Zhongshan Station optical aurora associated with the solar wind negative pressure impulse

The field of views of the Syowa East HF radar covers over Zhongshan Station (magnetic latitude ~ 74.5°S). We examined the relation between HF radar signatures and optical aurora by using the data obtained on 3 August 1997. A geomagnetic negative sudden impulse (SI(-)) occurred at ~ 1432 UT on 3 August 1997 associated with the sudden decrease of solar wind plasma density. From the behavior of the optical aurora observed by all-sky TV camera and scanning photometers at Zhongshan Station, a sudden enhancement of auroral emission intensity and poleward moving signature occurred associated with the negative Sl. It is interesting that the temporal and spatial variations of the HF radar backscatter power showed one to one correlations with optical aurora data. The details of this event are examined and compared with the data onboard WIND satellite and from ground based magnetometers

Preliminary result of imaging riometer at Zhongshan Station, Antarctica

An imaging riometer with 8 x 8 antenna array was installed successfully at Zhongshan Station, Antarctica in January 1997. The structure and working principle of the instrument are described. The first set of observation data is analyzed and the quiet day curve (QDC) are deduced. Preliminary results show that cosmic noise absorption is very different between night side and magnetic noon. In night side, there are often short-duration impulsive absorption events with a large absorption area in the northern side of the station, stretching in an east-west direction. In magnetic noon the absorption event is continuous, which lasts for more than 1 h with the absorption area strengthening in the northern and southern sides and weakening in the middle. It is thought that the absorption is caused by aurora particle precipitation in night side and by soft particle precipitation or convection in cusp at magnetic noon

The extremely intense CNA events observed at Zhongshan Station in July, 2000

Using the ground observation data at Zhongshan Station of Antarctica during July 13 to 17, 2000, the intense absorption events associated with the activities of the solar active region R9077 are analyzed. It was shown that an intense polar cap absorption event lasted more than 3 days, which was caused by the solar proton event associated with the X5/3B major flare at 1024 UT on July 17, with a typical day-night variation. At the same time, the intense solar activities extremely disturbed the magnetosphere, therefore aurora substorms occurred frequently. The energetic particle precipitation from the magnetosphere caused several absorption spikes superposing on the background of polar cap absorption. One distinct event is the absorption enhancement that started at about 0300 UT on July 15, reached its peak of 26dB at about 0645 UT and recovered at about 1110 UT on the same day, which was the strongest absorption event observed at Zhongshan Station since the imaging riometer installed in February, 1997. Another outstanding absorption spike with pulsation occurred at about 1753 UT on 14th, its peak reached to 6 dB

Post-noon ionospheric absorption observed by the imaging riometers at polar cust/cap conjugate stations

An example of post-noon ionospheric absorption observed by the imaging riometers at Ny-Alesund / Danmarkshavn in the arctic region and Zhongshan Station in Antarctic is presented. The post-noon absorption observed simultaneously between the hemispherical stations was a spike-type with weak intensity (< 1 dB) during the high solar wind dynamic pressure. The absorption spikes might be caused by precipitation of high-energy electrons (30 - 300 keV) in the closed dayside magnetosphere. It should be noted that the precipitation region of the absorption spike associated with the steep pressure increase (~ 13 nPa) was localized and shifted equatorward