A study of Geomagnetic Field and It s secular variation at the Location Brazilian Anomaly (25% 45°W).

In this paper we study and analysis the total intensity ( F ) and the horizontal component (H) of the geomagnetic field at the location namely Brazilian Anomaly (lat 25°S, long 45°W), in which the geomagnetic field intensity has a minimum value. We examine the relationship between the ( F , H ) with altitude at a certain latitude, and relationship between (F9H) with the latitude at the certain altitude .We study also the nature of the secular variation of the geomagnetic field at the same location during one century (1900-2000) , we found that the rate of change of field intensity (F) is roughly (9.3 % per century). The geomagnetic field data is obtained by using IGRF10 model at Brazilian anomaly (long 45°W),