Estimating Rainfall in Rodrigues by Geostatistics: (A) Theory

This paper introduces the geostatistical method. Originally devised to treat problems that arise when conventional statistical theory is used in estimating changes in ore grade within a mine, it is, however, an abstract theory of statistical behaviour that is applicable to many circumstances in different areas of geology and other natural sciences. Using rainfall at Réduit and at Citronelle as examples, the key concepts that are explained are the regionalised variable, the variogram and the kriging procedure. A list of fields where the method has been applied is given. What is common to these different applications is the regionalised variable, function of space/time with some kind of correlation in the spatial distribution of these magnitudes. Once the link of a parameter with space or time has been established or suspected, a geostatistical analysis may be tried.Keywords: regionalised variable, variogram, semivariance, krigin