A PCA-Based Reanalysis Method for Low- and Mid-Latitude Ionospheric Electrodynamics and Its Preliminary Application

We present a new method to study low- and mid-latitude ionospheric electrodynamics using principal component analysis. The method starts from an empirical electric potential model derived from long-term ROCSAT-1 observations. Key spatial patterns of the electric potential are extracted and converted into plasma drift velocity patterns in geomagnetic coordinates. This approach allows sparse satellite measurements to be represented consistently, enabling global mapping of electrodynamic parameters. It captures major physical processes in the ionosphere, including the morning E-region dynamo, the combined effects of daytime E- and F-region dynamos, and the evening pre-reversal enhancement. Seasonal variations in plasma drift are also well reproduced. By maintaining the climatological background while extracting weather-scale variations, this method provides a robust tool for modeling low- and mid-latitude ionospheric electrodynamics, with potential for further development.