The choice of working variables in the geostatistical estimation of the spatial distribution of ion concentration from acid precipitation

摘要: Ordinary kriging presents an optimal tool to estimate the spatial distribution of ion concentration from acid precipitation and produce risk-qualified maps phenomenon over studied area. However, being expressed as a linear combination data values, estimator should not be calculated directly values unless their corresponding volumes are essentially constant In theory, combinations volume-weighted concentrations considered, meaning that estimates obtained by dividing kriged depositions totals. practice, choice appropriate working variables for estimation will depend on nature phenomena objective study. this paper, effect results is illustrated through comparison experimental direct quotient. It appears even with fairly totals respect given small correlation between both variables, discrepancies two approaches can significant, especially at local scale: estimated varies locally according each procedure, level uncertainty systematically better predicted quotient, though it based approximate formula. order avoid misleading results, applied only global purposes after its practical equivalence quotient has been appraised.