Erosivity represents the rains property to cause erosion. The parameters used to investigate it depend on the occurrence of rain which is directly linked to the atmospheric phenomena that originate and distribute it spatially. The objective of this work is to spatialize erosivity in the DF and to explain through dominant atmospheric circulation its spatial-temporal variation.

Precipitation data from 1979 to 1995 were used to calculate erosivity. Spatialization was obtained based on Krigging`s geostatistic method. Since the region`s climate presents an alternation of dry and rainy periods, the variation in erosivity (shown in the cartograms) was analysed during these two periods. The dislocation of air masses is the main element used to explain the weather patterns. In the Center-West region of Brazil the continental equatorial (mEc), ropical atlantic (mTa) and polar atlantic (mPa) air masses operate. Associated with these air masses are three systems of atmospheric circulation which determine the region`s climate. The domination of these systems determines, in the summer, the dislocation of the cyclonal center (low pressure and high temperature) to dominate the Center-West region. The mEc, favoured by low pressure, and being hot and wet, carries rain and high temperatures to the region. The cartogram representative of this period shows high levels of erosivity. In the winter, when erosivity levels decline, the polar anticyclone migrates to the north and stops over the Center-West region.

Being a center of high pressure and low temperature, the polar antyciclone`s presence provokes cold and dry weather. Thus, the erosivity in the DF, from a seasonal perspective, follows the rain pattern. From the spatial perspective, it presents ana east-west tendency in erosivity growth. This tendency can be explained by the relief, which by interacting with the regional systems of atmospheric circulation acts over the region`s climate determining rain distribution patterns.