Comparison of Data from Rain Gauges and the IMERG Product to Analyse Precipitation in Mountain Areas of Central Italy

Matteo Gentilucci,Margherita Bufalini,Marco Materazzi,Fabrizio D’Aprile,Gilberto Pambianchi

doi:10.3390/ijgi10120795

Matteo Gentilucci, Margherita Bufalini + Show 3 more

Open Access

https://doi.org/10.3390/ijgi10120795

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Abstract

In central Italy, particularly in the Umbria-Marche Apennines, there are some complete, high-altitude weather stations, which are very important for assessing the climate in these areas. The mountain weather stations considered in this study were Monte Bove Sud (1917 m.a.s.l.), Monte Prata (1816 m.a.s.l.) and Pintura di Bolognola (1360 m.a.s.l.). The aim of this research was to compare the differences between the precipitation measured by the rain gauges and the data obtained by satellite using the IMERG algorithm, at the same locations. The evaluation of possible errors in the estimation of precipitation using one method or the other is fundamental for obtaining a reliable estimate of precipitation in mountain environments. The results revealed a strong underestimation of precipitation for the rain gauges at higher altitudes (Monte Bove Sud and Monte Prata) compared to the same pixel sampled by satellite. On the other hand, at lower altitudes, there was a better correlation between the rain gauge value and the IMERG product value. This research, although localised in well-defined locations, could help to assess the problems in rain detection through mountain weather stations.

Highlights

The aim of this study is to analyse rainfall and snowfall in mountain areas, and in particular to investigate the problem of the probable marked underestimation that affects high-altitude rain gauges
In the mountain environment there are greater problems than in other places in collecting precipitation data; for example, it has been shown that, in some cases, wind speed can result in an underestimation of rainfall and snowfall, by up to 80% if the speed is greater than 10 m/s [5,6], while rain gauge wetting and rain drop splashing are negligible and common to rain gauges, even at lower altitudes [4]
There is a difference between rain gauge data and Integrated Multi-satellite Retrievals for GPM (IMERG) satellite data; in the case of MB and Monte Prata (MP), satellite data is significantly higher, while in the case of Pintura di Bolognola (PB) the satellite data is similar to the rain gauge data

Summary

Introduction

The aim of this study is to analyse rainfall and snowfall in mountain areas, and in particular to investigate the problem of the probable marked underestimation that affects high-altitude rain gauges. Discrepancies have often been found between the data obtained from the interpolation of weather stations at altitudes below 1000 m in mountainous areas and the precipitation measured at higher altitudes [1,2] These differences, even when they are considerable, have not been sufficiently investigated in order to understand the possible malfunctions of rain gauges or to see whether it rains less than expected in mountain areas. The current stateof-the-art is ambiguous with regard to an accurate understanding of the problems of rain gauges in high mountain weather stations or possible discrepancies in satellite data [14,15]

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