Temporal Variability of Temperature Extremes in the Sardinia Region (Italy)

Tommaso Caloiero,Ilaria Guagliardi

doi:10.3390/hydrology7030055

Abstract

In this paper, the temporal tendencies of temperature data from the island of Sardinia (Italy) were analyzed by considering 48 data series in the period 1982–2011. In particular, monthly temperatures (maximum and minimum), and some indices of daily extremes were evaluated and tested to detect trends using the Mann-Kendall non-parametric test. Results showed a positive trend in the spring months and a marked negative trend in the autumn-winter months for minimum temperatures. As regards maximum temperatures, almost all months showed positive trends, although an opposite behavior was detected in September and in the winter months. With respect to the extreme indices, a general increasing trend of the series was detected for the diurnal temperature range (DTR), frost days (FD), summer days (SU25), warm (WSDI) and cold (CSDI) spells. As regards tropical nights (TR20), an equal distribution of positive and negative trends has emerged. Results of the spatial analysis performed on the trend marks suggested that Sardinia’s topography could influence temperature variability.

Highlights

In its latest special report, the IPCC evidenced a temperature rise of approximately 1.0 ◦ C above pre-industrial levels, caused by human activities, and forecast that it will likely reach 1.5 ◦ C between 2030 and 2052 [1]
A negative trend has been detected in 13.0% (SL = 90%) and minimum temperatures at a planetary scale evidenced an increase in the minimum values rather than the maximum ones [66], results of this study evidenced an opposite behavior, confirming the findings achieved by previous research performed in Italy [41]
(Italy) was carried out to identify the trends, and to analyze the behaviors of the extreme detected a general underestimation of both minimum and maximum temperature extremes for simulations driven by the CMCC–CM global model

Summary

Introduction

In its latest special report, the IPCC evidenced a temperature rise of approximately 1.0 ◦ C above pre-industrial levels, caused by human activities, and forecast that it will likely reach 1.5 ◦ C between 2030 and 2052 [1]. Even though trend assessment of mean temperature is significant, analysis of the extreme temperature tendencies, at small spatial scales is paramount, given its impacts on several natural processes and human activities, such as hydrology, food security assessment, crops, agro-ecological zoning, as well as human health and comfort [6,7]. Temperature increase can affect hydrological processes, speeding up the circulation of water vapor and influencing the spatiotemporal distribution and intensity of precipitation [8]. It directly influences hydrological features such as evaporation, runoff and soil water, which could raise the number of extreme climate events.

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Conclusion