Trend detection of annual and seasonal rainfall in Calabria (Southern Italy)

Abstract

ABSTRACT:In order to investigate the behaviour of climatic and hydrological variables, several statistical and stochastic techniques are currently applied to time series. In the present study a statistical analysis of annual and seasonal precipitation has been performed over 109 cumulated rainfall series with more than 50 years of data observed in a region of Southern Italy (Calabria). Trend analyses have been made by using both nonparametric (Mann-Kendall test) and parametric (linear regression analysis) procedures. The long historical series of monthly rainfall data employed in this work have been previously processed through a pre-whitening (PW) technique in order to reduce the autocorrelation of rainfall series and its effects on outcomes of trend detection. The application of the above mentioned procedures has shown a decreasing trend for annual and winter-autumn rainfall and an increasing trend for summer precipitation. Moreover the Mann-Whitney test has been used to evidence the possible change points in the data. The higher percentages of rainfall series show possible year changes during decade [1960][1961][1962][1963][1964][1965][1966][1967][1968][1969][1970] for almost all of the temporal aggregation rainfall.

Analysis of Costantino Landslide Dam Evolution (Southern Italy) by Means of Satellite Images, Aerial Photos, and Climate Data

“…Conversely, positive rainfall trends have been detected during summer months (+0.8 mm/three months, from July to September-MK test > 98%). Overall, the results are consistent with those of previous studies [65][66][67][68][69]. As reported by [69], the negative trend of annual rainfall data is a typical feature of all the long aggregation rainfalls observed in the Calabria Region and especially on the Southern Ionian side of Calabrian territory.…”

“…Overall, the results are consistent with those of previous studies [65][66][67][68][69]. As reported by [69], the negative trend of annual rainfall data is a typical feature of all the long aggregation rainfalls observed in the Calabria Region and especially on the Southern Ionian side of Calabrian territory. Moreover, also the general significant increase of rainfall during summer months and the significant decrease of rainfall in autumn/winter months is well spatially distributed on the Southern Ionian side of Calabrian territory.…”

Analysis of trends and sudden changes in long-term environmental data from King George Island (Antarctica): relationships between global climatic oscillations and local system response

“…In case of existing turning points, the Pettitt U t shows local maximum values in the time series for these points. This test is extremely useful for detecting shifts in the median of a sample series with unknown turning point, since, in any case, it provides the most probable changing point of the series, which corresponds to the greatest U t value in the sequence (Caloiero et al 2011). U t values were calculated for each available monthly mean of the different variables and subsequently plotted to visualize the turning points ( Fig.…”

The implications of geography and climate on drought trend

“…Therefore, the Mann-Kendall test can be applied for trend analysis using monthly and seasonal climatic data (Kadıoglu and Aslan, 2000) and has been used in research on precipitation changes with respect to geographical factors, differentiated by season (Sinoga et al, 2011 Ezber et al (2007), Mourato et al (2010), Caloiero et al (2011), andMitra et al (2012). Mann-Kendall statistic S is computed as follows (Burn, 1994;Westmacott and Burn, 1997):…”