Correlation of the astrometric latitude residuals at Mizusawa and Tokyo with the southern oscillation index on an interannual time scale.
The El Nino/southern oscillation (ENSO) is the most prominent interannual fluctuation in the atmosphere-oceanic system. A single index SOI (Southern Oscillation Index), based on the sea level pressure difference between Tahiti and Darvin, is conventionally used to describe the ENSO phenomenon. Its linkage to other geophysical phenomena is being studied now. The paper studies the correlation of SOI with the latitude residuals by means of cross correlation in using the latitude observational data of the six astrometric instruments at Mizusawa and Tokyo: the Zenith Telescope (1900-1978), the Photographic Zenith Tube No. 1 and No. 2 (1962-1975; 1975-1992), the Floating Zenith Telescope(1967-1984) and the astrolabe (1966-1984) at Mizusawa; the Photographic Zenith Tube at Tokyo (1966-1988). It appears that the latitude residuals at Mizusawa and Tokyo have a significant correlation at interannual time scale with the SOI, the SOI leading latitude residual of about 2-3years.
- Astronomy and Astrophysics
- Pub Date:
- May 1996
- METHODS: DATA ANALYSIS