Acquaotta, F.

Fratianni, S.

Venema, V.

English

Acquaotta, Fiorella

Fratianni, Simona

Institutional Research Information System University of Turin

EMS Annual Meeting AbstractsVol. 10, EMS2013-10, 201313th EMS / 11th ECAM© Author(s) 2013Comparison study of two independent precipitation networks in NorthWest ItalyF. Acquaotta (1), S. Fratianni (1), and V. Venema (2)(1) University of Turin, Earth Science, Turin, Italy (fiorella.acquaotta@unito.it, +390116705146), (2) Meteorological Institute,University of Bonn, Auf dem Huegel 20, 53121 Bonn, GermanyExtreme weather and climate events have a deep impact on society. Climatologists are thus increasingly interestedin studying changes in the intensity, frequency, duration and spatial distribution of such events. Unfortunately,long instrumental climate records are usually affected bynon-climatic changes (inhomogeneities), which compromise such studies. The most direct way tostudy non-climatic biases relies on parallel measurements.Two independent climate networks in North West Italy, offer the unique possibility to study such an inhomogeneityin the precipitation record. From this dataset we could identify 20 pairs of stations with up to 15 years of overlap,which can be used to study the influence of the transition to automatic precipitation measurements on thehomogeneity of the precipitation record.For each stations a continuous and accurate historical research is available that has allowed us to create, for everylocation, a metadata file. Then a manual quality control was carried out using the software RClimdex (Zhang etal., 2004). The program highlights obviously wrong precipitation data, such as negative values, and creates plotshad allow the identification of outliers.In order to make a direct comparison between the daily pluviometric series, missing values in one series werealso set to be missing in its counterpart before computing monthly statistics. For the precipitation series we haveanalyzed the monthly precipitation sums and the number of rainy days, i.e. days with precipitation ≥ 1mm.Subsequently, from the monthly precipitation amounts, the series of their ratios have been calculated and for therain days the series their difference. Over the new series a statistical analysis has been carried out and the extremevalues, values that fall in the distribution tails, have been checked by examining the daily values of precipitationseries. Moreover we have divided the daily precipitation in five precipitation classes. that allows us to compare ifdifferences in the strength of precipitation events depend on the magnitude itself.The work has shown most clearly that the inhomogeneity have affected for small precipitation amounts and thenumber of precipitation days, whereas strong precipitation is not much affected.

Comparison study of two independent precipitation networks in NorthWest Italy

https://iris.unito.it/bitstream/2318/144798/1/EMS2013-10.pdf

Comparison study of two independent precipitation networks in NorthWest Italy

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