TRMM-based rainfall temporal analysis over Italy

Caloiero, T.; Caroletti, G. N.; Coscarelli, R., 2020, TRMM-based rainfall temporal analysis over Italy, SN Applied Sciences 2 (2020). doi_10.1007/s42452-020-3075-7,

Rainfall is an irregular phenomenon showing large spatial variability. Unfortunately, spatially distributed data are not always available, because rain gauge networks are not continuously dense and adequately distributed, and they provide only point measurements. In this work, the temporal variability of rainfall in Italy has been investigated using the Tropical Rainfall Measuring Mission monthly product for the period 1998-2018. Within this aim, more than 650 grid points falling within the Italian territory have been selected. In order to evaluate the presence of trends and their significance, the monthly, seasonal and annual rainfall series were analysed at each grid point with the Mann-Kendall nonparametric test and the Theil-Sen estimator. The broad extension of the area under investigation allowed a better understanding of rainfall trend patterns over space. At annual scale, results evidenced few relevant trends, either positive or negative, involving central Italy (negative trend) and southern Italy (positive trend). A similar trend behaviour has been identified, at seasonal scale, in autumn, with a clear spatial difference between the north and the south of Italy, in winter for the negative trend and in spring for the positive one. In summer, only few grid points in central Italy showed a significant increasing trend.

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