A teoria da entropia aplicada no estudo da precipitação pluvial e da vazão fluvial no Nordeste do Brasil.

Abstract

Using the Shannon entropy, the space-time variability of rainfall and runoff was assessed for daily rainfall and runoff data for a 10-years period from 189 stations in the northeastern region of Brazil. Mean values of marginal entropy were computed for all observation stations and isoentropy maps were then constructed for delineating annual and seasonal characteristics of rainfall and runoff. The Mann-Kendall test was used to evaluate the long-term trend in marginal entropy as well as cross-entropy for two sample stations. The marginal entropy values of rainfall and runoff were higher for locations and periods with highest amount of rainfall. For both rainfall and runoff, the results also showed that the marginal entropy decreased exponentially with increasing coefficient of variation, but there was no significant relation between cross-entropy and the coefficient of variation. The Shannon theory produced spatial patterns which led to a better understanding of rainfall and runoff characteristics throughout the northeastern region of Brazil. Trend analysis indicated that most time series did not have any significant trends, mainly for crossentropy. The total cross-entropy indicated that rainfall and runoff carried the same information content for annual and rainy season periods.