The Effect of Data Resolution on the Area Threshold Method

Abstract

The effect of data resolution on the area threshold method is studied using a stochastic model of radar snapshots of tropical rainfall taken during the Global Atmospheric Research Program Atlantic Tropical Experiment. The results indicate that significant biases and random error can arise when using radar or satellite data having spatial resolutions different from those used to calibrate the area threshold method. Although the use of a threshold decreases the bias and random error in the fractional coverage of rain rates, the larger calibration coefficients associated with larger thresholds tend to increase the bias and random error in the resulting areal mean rain-rate estimates.