Coupled Spatial Distribution of Rainfall and Temperature in USA

In the last decades, the international scientific literature has focused on the assessment and quantification of trends in average temperature and rainfall, underlining changes in time and space sometimes relevant. The changes concern the yearly average values, the seasonal distribution, the daily values, with marked differences both at a continental and national scale. In this paper, with reference to a database containing the records of about 8000 thermometric stations and 12000 rainfall stations for the period 1895-1997 for the USA, available on the website of the Institute for Mathematics Applied to Geosciences ( http://www.image.ucar.edu/Data/US.monthly.met/ ), an analysis on the spatial correlation between the yearly average rainfall hc and the mean of the yearly average ground temperature T was performed. In particular, with the aid of the copula distribution function, a stochastic model to define the conditional probability distribut *ion P(hc(mm)|T(°C)) was developed, analyzing the dependence of the yearly average rainfall on the thermometric changes.