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The analysis of 20-year long-term semidiurnal lunar tidal variations gave the evidence that the semidiurnal variations are completely different between the magnetic quiet and disturbed periods. This is the first time that the seasonal dependence of disturbance-time semidiurnal variation has been provided from the analysis of the EE-index. We found the Kp dependence of semidiurnal variation: For full and new moon phase, counter troughs are amplified during disturbance time, possibly related to disturbance dynamo. For all moon phase, there are positive enhancements in dawn and strong depressions after sunset, resulting from the penetration of polar electric filed. For Seasonal dependence, semidiurnal variations are divided to three seasonal groups, and characterized as deep trough, enhanced crest and weak structure for D-solstice, Equinoxes and J-solstice, respectively. There is no significant longitudinal difference between Ancon and Davao, except for the amplitude of semidiurnal variations. The deep troughs occur during D-solstice and the enhanced crests during Equinoxes, at both Ancon and Davao.

We examined the Schumann resonance (SR) at low-latitude station KUJ by comparing with solar X-ray flux and solar proton flux at a geostationary orbit. For intense solar activity in October-November 2003, the reaction of the SR frequency to X-ray enhancement and SPEs was different. The SR frequency in H component increased at the time of the Xray enhancement. The response of SR seems to be caused by the increase of the electron density in the ionospheric D region which ionized by the enhanced solar X-ray flux. In the case of the SPEs, the SR frequency in D component decreased with enhancement of solar proton flux. We suggest that the SPEs caused the decrease of altitude on the ionopheric D region at high-latitude region, and the SR frequency decreased.

For study of coupling processes in the Solar-Terrestrial System, International Center for Space Weather Science and Education (ICSWSE), Kyushu University has developed a real time magnetic data acquisition system (the MAGDAS project) around the world. The number of observational sites is increasing every year with the collaboration of host countries. Now at this time, the MAGDAS Project has installed 78 real time magnetometers – so it is the largest magnetometer array in the world. The history of global observation at Kyushu University is over 30 years and number of developed observational sites is over 140. Especially, Collaboration between IKIR is extended back to 1990's. Now a time, we are operating Flux-gate magnetometer and FM-CW Radar. It is one of most important collaboration for space weather monitoring. By using MAGDAS data, ICSWSE produces many types of space weather index, such as EE-index (for monitoring long tern and shot term variation of equatorial electrojet), Pc5 index (for monitoring solar-wind velocity and high energy electron flux), Sq-index (for monitoring global change of ionospheric low and middle latitudinal current system), and Pc3 index (for monitoring of plasma density variation at low latitudes). In this report, we will introduce recent development of MAGDAS/ICSWSE Indexes project and topics for new open policy for MAGDAS data will be also discussed.

The ground magnetic field variation in the extremely low frequency (ELF) range has been measured by an induction magnetometer at Kuju, Japan (KUJ; M.Lat. = 23.4 degrees, M. Lon. = 201.0 degrees) since 2003. The first mode of the Schumann resonance (SR) around 8 Hz can be seen at KUJ. The SR in H (horizontal northward component) shows maximum peaks around 08 UT and 15 UT. In the case of D (horizontal eastward component), the SR shows its maximum peak around 08 UT. These peaks are coincident with the enhancement of lightning activity in Africa and Asia. Thus, we found the influence of the lightning activity on the observed SR at KUJ.