Variación secular reciente y cartas de los elementos del campo geomagnético en México

Abstract

We present a series of synthetic maps of the elements of the geomagnetic field in Mexico prepared from the International Geomagnetic Reference Field (IGRF) values. The synthetic maps include inclination, declination, vertical, horizontal and total intensities and their corresponding secular variations. Observational data of temporal variations of the geomagnetic field for central Mexico (Magnetic Observatory of Teoloyucan) are analyzed for 1923 to 1987. Total intensity has decreased at arate of 48.07 nT per year and the direction has been shifting from east to west and towards higher inclinations. Comparisons of the Observatory data with IGRF-derived valuef. for the period 1945-1990 suggest that IGRF provides an excellent estimation of geomagnetic parameters in this low latitude region. The good fit of IGRF to observed variations of geomagnetic parameters indicates an absence of significant anomalies of the geomagnetic secular variation in central Mexico.