IPY Expression of Intent #422 Interhemispheric Study on Conjugacy and Non- conjugacy of Auroral and Polar Ionospheric Disturbances using Ground-based Observation Network Interhemispheric Study on Auroral Phenomena Akira Kadokura 1, Natsuo Sato 1, Hisao Yamagishi 1, Hiroshi Miyaoka 1, Makoto Taguchi 1, Akira S. Yukimatu 1, Yusuke Ebihara 1, and many other collaborators 1 National Institute of Polar Research, Japan

Concise outline of proposed activity ① To maintain and intensify the pre-existing conjugate auroral latitude observations between Syowa Station in Antarctica and observatories in Iceland. We have carried out the conjugate ground- based observations continuously since 1984, using the 3-axis fluxgate magnetometer, 3-component induction magnetometer, riometer, and VLF receiver. We have also carried out auroral optical observation in the whole season at Syowa and mainly during the equinox period at Iceland. So far, many studies concerning the interhemispheric comparison of various auroral latitude phenomena have been done using the observed data. Such a long-term observation is very valuable to monitor the long-term variation of the geospace environment surrounding the earth and can contribute to the Space Weather study. During the IPY period, we would like to renew the data acquisition system to transfer the data to Japan in near real time and the data archiving system to make the data accessible for the community more quickly and more easily. We would like to also introduce a well-calibrated automatic optical observation system in Iceland, which enables us the auroral observation in the whole season.

Concise outline of proposed activity ② To develop the network of the unmanned magnetometer system in the Antarctic. We have already introduced 6 sets of the unmanned magnetometer system. Four of them were supplied from British Antarctic Survey (BAS) and two were developed in National Institute of Polar Research (NIPR). The data from our system can be obtained via Iridium satellite system in near real time. We will further develop and sophisticate our own system, and would like to increase the number of the observation points during the IPY period, collaborating with pre-existing and planning manned and unmanned magnetometers by other countries.

Concise outline of proposed activity ③ To maintain other ground-based facilities at Syowa Station, including the Super Dual Auroral Radar Network (SuperDARN) Syowa South and Syowa East HF-radars and the imaging riometer. Both are operated in the framework of the international collaboration for global network observation. We will make the data archiving system of these observations more easily accessible for the community.

Mapping of Northern/Southern hemispheres with geomagnetic coordinate

Conjugate point of Syowa Station (IGRF model) Station Glat (deg) Glon (deg) Inv.lat (deg) Mlon (deg) MLT (hr) at 0.0 UT L value D (deg) I (deg)B (nT) Tjornes Syowa Comparison of geomagnetic parameters (Epoch: 23:20:00 UT, 26 Sep, 2003)

SYOWAIceland Fluxgate magnetometer ○ Induction magnetometer ○ Riometer ○ VLF receiver ○ Imaging Riometer ○ All-sky TV camera ○ (only equinox) All-sky monochromatic Imager ○ (from 2005) Meridian Scanning Photometer Fabry-Perot Imager SuperDARN radar ○ MF-radar Ionosonde Multi-beam VHF Doppler radar Instruments at conjugate stations

Unmanned sites in the southern hemisphere

Unmanned magnetometers in JARE Dome Fuji Syowa JARE-44 (2003) BAS-LPM ① Skallen [-69°40′24″, 39°24′07″E] /15 ~ /14 ② Cape Omega [-68°34′39.4″, 41°04′54.1″E] /31 ~ /28 ③ H100 [69 ° 17'44"S, 41 ° 19'15"E] /2 ~ /22 ④ Dome Fuji [ 77°19'01"S, 39°42'12"E ] /6 ~ /29, / /9 Yamato Mt. H100 Belgian New Station Mizuho １ ２ ３ ４ JARE-45 (2004) BAS-LPM ① H100 [69°17'44"S, 41°19'15"E] /18 ~10/20, 10/20~ ② Mizuho [70°42‘7.7"S, 44°17‘4.1"E] /18 ~ ③ Middle Point [74°00’37.0"S, 42°59’30.4"E] /29 ~ ④ Dome Fuji [77°19'01.6"S, 39°42’31.7"E] / JARE-46 (2005) NIPR-LPM ① S122 [70°01'16"S, 43°07'39"E] ② MD120 [71°49'38"S, 44°16'27"E] JARE-45 BAS-LPMs are continued. 1 2

Comparison of BAS and NIPR type LPMs BAS-LPMNIPR-LPM MagnetometerMAG-03MC Resolution16 bit Noise level1 nT0.2 nT Low Pass Filter100 Hz15 Hz Power consumption (1 sec sampling) 0.42 W0.16 W Data acquisitionFlash memory card Iridium satellite Flash memory card Command sending × ○

Development of NIPR model LPM  Power consumption ： 0.16 W (winter-time, 1sec sampling)  Magnetometer ON time : 100ms at each sampling  Resolution: 0.2 nT, LPF cutoff: 15 Hz  Data recovery ： By Iridium, once/day  Telecommunication: Data acquisition & Command sending Iridium satellite Transmit time : about 20 min for 1 day data (1 sec sampling)

-, Omega H100 SYOWA Skallen BAS-LPM sites in JARE-44 ( ) （ 3 sites around Syowa, Dome Fuji ） SITELat (deg)Lon (deg)Alt （ m ） Start dayEnd dayDays H100-69°17′44″41°19′15″E1, ２９３ Skallen-69°40′24″39°24′07″E ２７２ Cape Omega -68°34′39″41°04′54″E ３６２ Dome Fuji-77°19′01″39°42′12″E3, １１２ ８０ｋ ｍ

Cape OmegaSkallen H100 Dome Fuji LPMs in JARE-44 in

Magnetic variation during UT on 28 March, 2003 Skallen Syowa Omega H100 Dome ① ②③

Equivalent current variation associated with WTS passage

Field test of NIPR model in JARE-46 in 2005

HF-radar network in the both hemisphere （ SuperDARN ）

Web page of WDC for Aurora