Rainfall observations using a rain gauge of 100 m2
Salvatore Grimaldi1,*, Andrea Petroselli2, Roberto Rapiti2, Giuliano Cipollari2, Paolo Valerio
Ciorba1
1
Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), University
of Tuscia, Via San Camillo De Lellis, snc, 01100, Viterbo, Italy; salvatore.grimaldi@unitus.it;
tel. +390761357326 ; fax +390761357389.
2
Department of Sciences and Technologies for Agriculture, Forestry, Nature, and Energy
(DAFNE), Università degli Studi della Tuscia, Via San Camillo De Lellis, snc, 01100, Viterbo,
Italy.
* Presenting Author
Measurement of precipitation is fundamental for many aspects of modeling in the natural
sciences, in particular within the hydrological cycle, because the rainfall is a key component
influencing several natural phenomena from infiltration to flood formation. The most diffuse
instrument measuring amounts and intensities of liquid precipitation is the rain gauge providing
direct observation at ground level. Such observations are considered as “true” precipitation and
are employed for calibrating other instruments useful for detecting precipitation at basin scale,
such as remote sensing devices (e.g. satellite-borne, airborne sensors and ground-based radars).
The main drawback of the standard raingauge is its small size causing possible errors in the
precipitation estimation due to the splash effect, the wind occurring in the instrument proximity,
and to the orifice’s limited dimension compared to the spatial drops distribution. Recently, a
giant-raingauge, with an unprecedented collecting surface of 100 m2, was designed and built in
the experimental farm of Tuscia University, in central Italy, with the aim of investigating the
role of the orifice dimension. Here a preliminary analysis of several rainfall events is presented,
comparing the rainfall intensities observed with the proposed apparatus to the ones recorded by
common raingauges at different timescales. Results suggest that significant differences can be
retrieved, in particular for low time resolutions (up to 15 minutes) and for high rainfall intensity
values.