Relationships between rainfall and throughfall in a secondary forest in southeastern Brazil: an evaluation of different statistical models

Throughfall (TF) is influenced by different meteorological conditions, which can result in high spatial and temporal variability, when interacting with vegetation and mutually with each other. This study aimed to evaluate rainfall (RF) influence on TF, as well as to describe the behavior of these variables in an area dominated by Pinus elliottii in southeastern Brazil, by exploring different statistical models proposed in the literature. For this, RF and TF data were recorded in 24 rainfall events by 180 gauges distributed in six 10 x 10 m plots. The results indicate a significant influence of RF volume on response variables [TF volume (TFmm), TF fraction (TF%) and coefficient of variation of TF (CVTF)]. While the linear model presented the best fit for TFmm, the non-linear models had better results for TF% and CVTF as a function of RF, allowing the identification of distinct behaviors for different RF volumes. In general, it was verified that RF is the main source of variability in TF estimates in the study area. However, it should be noted that other variables may be acting simultaneously on TF% and CVTF, in which 45.4 and 38.1% of the variation, respectively, remain unexplained, requiring complementary studies to identify and quantify the influence of other factors.