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*Oc ฒaq[1], ์เV ๅฟ[2], ฌ์ ืM[2]
กไc ฏq[2], Asgeir Brekke[3]
sqๅwปใะ๏w[1]
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ยซค[2]
Auroral Observatory, University of Tromsoe[3]
A special experiment of the EISCAT UHF radar and ESR for neutral winds and temperature observations
*Sawako Maeda[1]
,Satonori Nozawa [2],Yasunobu Ogawa [2]
Seiko Imaida [2],Asgeir Brekke [3]
Faculty for the Study of Contemporary Society, Kyoto Women's University[1]
Solar Terrestrial Environment Laboratory, Nagoya University[2]
Auroral Observatory, University of Tromsoe[3]
Observations of the E-region neutral winds and temperature by the EISCAT UHF radar ( 69.6N) were coordinated with those of ESR (78.2N) in a special programme experiment between 10:00 UT in July 09 and 13:00 UT in July 10, 2001. This paper will report the outline of the experiment and its objectives.
An analysis of the Common Program 2 (CP-2) data obtained by the EISCAT UHF radar suggested that the neutral dynamics in the quite-time E-region is characterized primarily by the so-called geostrophic balance and the vectors of the neutral wind follow isobars (Maeda et al., 1999). The meridional temperature gradient inferred from the neutral wind vector was northward during the dayside summer time. Our study by using the CP-2 data of the EISCAT UHF radar and ESR showed that the neutral temperature at Svalbard is higher than that at Tromsoe during the daytime (Maeda et al., 2001). However, it is not clear how the tempera- ture gradient derived locally from the neutral wind vectors relates to the temperature difference over the horizontal distance between Tromsoe and Longyearbyn of the horizontal distance of about 1000 km.
In 1998, a special programme experiment by the EISCAT UHF radar was conducted to derive a meridional temperature gradient directly by the north and south beams with low elevation angle of 30combined with the cp2-type beams (Maeda et al., 2000). The horizontal distance between the antenna positions was about 150 km. Because of the short term experiment (5 hours) and system failure, the direction of the temperature gradient scattered significantly.
The present experiment is an improvement on the previous one in terms of the coordination of the two radars and the 27 hours experiment. The antenna cycles of the two radars are as follows:
EISCAT UHF radar; north -> CP2 -> south -> CP2
ESR ; south+FA -> CP2L-> south+ FA -> CP2L
The cycle time of the EISCAT UHF radar and ESR was 45 minutes.
Another objective of the experiment is to study the atmospheric tides in the region from about 90 km height by using the data obtained from the CP2 and CP2L at the two stations, respectively.
The preliminary results will be presented.
References
Maeda et al., J. Geophys. Res., 104, 19871, 1999.
Maeda et al., Adv. Polar Upper Atoms. Res., 14, 128, 2000.
Maeda et al., SGEPSS spring meeting, 2001.