Determinação da evapotranspiração pelos métodos dos balanços hídrico e de cloreto e a quantificação da interceptação das chuvas na Mata Atlântica: São Paulo, SP e Cunha, SP

Abstract

CICCO, V. Evapotranspiration determination by the methods of water and the chloride balances and the quantification of canopy interception in the Atlantic Forest: Sao Paulo, SP and Cunha, SP. 2009. 138 f. Tese (Doutorado) – Departamento de Geografia da Faculdade de Filosofia, Letras e Ciencias Humanas, Universidade de Sao Paulo, Sao Paulo, 2009. The present study aims the quantification of the interception of the rains by the trees canopy and the determination of the real evapotranspiration by the methods of the water and the chloride balances. For that, it was established the monitory of two experimental catchments situated at Dense Ombrofila Forest (Atlantic Forest) one of them, in Parque Estadual das Fontes do Ipiranga (PEFI) and the other in Parque Estadual da Serra do MarCunha Nucleus both in Sao Paulo State. The interceptions estimated for the IAG-PEFI and for the B-Cunha catchments were of 21.6% and 24.0%, at the same time. According to the D`Agostino-Pearson test for the transformed values, of the precipitation and the transprecipitation it was verified normal distribution at the level of significance 5%. The analysis results of simple linear regression presented coefficient of elevated determination for the IAG-PEFI (92.0%) and Cunha (88.6%). The analysis through the test of D`Agostino-Pearson for the absolute values and transformed from interception do not followed normal distribution. Thus, it was applied the test of correlation of Spearman, being of 0.545 for the IAG-PEFI and the 0.524 for Cunha showing a positive moderate correlation for the level of 5% significant. The small difference found in the interception of the rains through the forests for the two locations might be explained by the canopy openings in IAG-PEFI of 34.2% and Cunha of 31.1%. During the water year of 2000 in the catchment of IAG-PEFI, the precipitation and the total streamflow were of 1,279.6 mm and 273.4 mm. The real evapotranspiration reached 1,006.2 mm, representing 78.6% from total precipitation, indicating a low water production (21.4%) For the water years of 2001, 2002 and 2003 in the B-Cunha catchments, the real evapotranspiration reached 696.4 mm (42.8%), 769.5 mm (47.7%) and 748.4 mm (44.0%), with average of 738.1 mm (44.8%), indicating a good water production (55.2%). The chloride by wet deposition total flux in the IAG-PEFI and B-Cunha catchments were of 7.26 kg.ha1.year and 7.57 kg.ha1.year1 and while the total flux through the streamflow were 7.15 kg.ha 1.year1 and 7.96 kg.ha1.year1. The results showed that the ion enter flux were much closed, indicating that the urbanization process suffered by PEFI spilled is not influencing in the precipitations. In the IAGPEFI catchment, the estimated real evapotranspiration was of 1,000.1 mm, that correspond the 78.2% of the total precipitation a much closed value to the water balance. In the B-Cunha catchment the estimated real evapotranspiration for the water years of 2001, 2002 and 2003 was of 898.6 mm (55.2%), 693.7 mm (43.2%) and 693.7 mm (40.8%), and the medium for the three years of 763.0 mm (46.3%), value a little superior to that obtained in the water balance. For the two catchments, the input and output chloride flux were basically the same. Then, we could infer that the ion is not a product of intemperism, and that its involvement in ionic change, or biologic process reach the balance, however, this ion may be consider conservative. The estimative of real evapotranspiration by the base flow for June 2000 in the IAGPEFI catchment, through the chloride method presented the value of 989.0 mm (77.3%). But in the B-Cunha catchment for August of the water year of 2001, the real evapotranspiration was of 450.5 mm (27.7%), value much lower obtained by the other methods, possible by the small number of sample realized. For the months of August and July of the 2002 and 2003 water years, the results were satisfactory, reaching 707.8 mm (43.9%) and 719.4 mm (43.3%).