A MATHEMATICAL TOOL TO RECOGNIZE IONOSPHERIC TSUNAMI DUE TO TROPICAL CYCLONE: A CASE SUCH AS TYPHOON NAKRI ON 29 MAY 2008

In this paper uses, a mathematical tool called two dimensional Principal Component Analysis (2DPCA) to determine total electron content (TEC) anomalies in the ionosphere for a Tropical Cyclone such as the Nakri Typhoon on 29 May, 2008 (UTC). 2DPCA are applied to the global ionospheric TEC data with transforms conducted for the time period 12:00 to 14:00UT on 29 May 2008 when the wind was most intense. Results show that at a height of approximately 150-200 km the TEC anomaly is more localized; however its intensity increases with height and becomes more widespread. The TEC anomaly is akin to an ionospheric tsunami. Potential causes of the results are discussed with emphasis given to vertical acoustic gravity waves. The approximate position of the typhoon's eye can be detected if the TEC data are divided into fine enough maps with adequate spatial-resolution at GPS-TEC receivers. This implies that the trace of the typhoon is caught using 2DPCA.