Mapas mensais de precipitação maxima e erosividade para o estado de São Paulo de interesse a engenharia

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

The objective of this work was to generate monthly maps of maximum intensity rains in 24 hours and of erosivity for the State of São Paulo, using monthly data of precipitation of maximum intensity of one day. The data of rain maximum in one day, of 343 were selected rain gage post of the State of São Paulo, operated by DAEE, with complete historical series 31 years old, alI beginning in 1962 and finishing in 1992. The estimates of probability of occurrence of maximum events of intensity of rain were calculated by the methodology proposed by GUMBEL(l958), based on a distribution of known frequency with the Tipo I of Fischer Tippett to two parameters. Starting ITom the maximum levels of intensity of rain of one day, they were made the disaggregations of rains of maximum intensity in 24 hours and in 30 minutes, according to the methodology proposed by OCClllPINTI &SANTOS(1966). With base in the levels of maximum precipitation in 30 minutes the erosivity indexes were calculated monthly EI30 for each one ofthe 343 places. The data were interpolated to generate 12 monthly maps of the levels of maximum intensity of precipitation in 24 hours and 12 monthly maps of erosivity. Maps of the maximum levels of erosivity of the rainy station were also generated, of the station it evaporates and of the annual totais of the erosivity in the State of São Paulo. The results of the calculations of the monthly levels of probability of rain of maximum intensity were submitted to the analysis of main components (ACP), with the advantage of the reduction ofthe number ofvariables of 12 for 4, without loss ofinformation. The results of ACP showed that the first four Main Components (ACP) they get to retain about 76% of the accumulated information of the original variables. The monthly maps of maximum precipitation were obtained through the georefferentiation techniques, interpolation and reclassification of the System of Geographical Information available in Idrisi.2. With views to the use in terracement, each map was reclassified in intervals of class of 10 mm rain. Finally, with base in the parameters and of the distribution of Gumbel and in the retum period T, monthly equations of estimates of rain of maximum intensity were developed in 24 hours and of erosivity EI30, for each one of the 343 places in the State, available in software of practical application. The obtained results ofthe rains interpolated in rnRISI 2.0, for the method ofthe nverse of the square of the distance they were shown effective, allowing to obtain intervals of maximum rain of24 hours ofto a millimeter in any place ofthe State of São Paulo. With this, the monthly maps of maximum rain show versatility for applications in planning of basins of contention of pluvial waters, drainage channels for terraces, besides aiding in projects of construction of bridges, barrages, overflow sistems and roads. The developed program allows, besides the maximum levels of rain in 24 hours in any retum period, to obtain estimates of monthly maximum erosivity for any place of the State of São Paulo, of application in engineering and more specifically in combat studies the erosion and spacing among terraces

ASSUNTO(S)

chuvas precipitação (meteorologia) - variabilidade solos - erosão

ACESSO AO ARTIGO

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