A MODEL FOR SOLAR QUIET DAY VARIATION AT LOW-LATITUDE FROM PAST OBSERVATIONS USING SINGULAR SPECTRUM ANALYSIS

Singular spectrum isolates significant principal components in a, time series from the embedded noise. This tool-kit is used to reconstruct trend-free individual time series, formed by restricting the mean mont hly hourly values of geomagnetic field to one hour at a time ata,low l atitude station Alibag (dipole latitude 9.5 degrees N). Each reconstru cted component is extrapolated over the next 12 values using an autore gressive model based on Burg's maximum entropy algorithm, Details of a numerical approach to increase the reliability of extrapolation are h ighlighted. The extrapolated reconstructed components are then combine d to generate predicted monthly values for each hour. The mean diurnal variation for any month obtained from the extrapolated individual hou rly time series compares favorably with the observations. This approac h to Sq(H) modelling incorporating both long and short term variations will be beneficial in the derivation of Dst index.