Detection of heat and cold waves in Montevergine time series (1884–2015)

Vincenzo Capozzi,Giorgio Budillon

doi:10.5194/adgeo-44-35-2017

Abstract

Abstract. In recent years, extreme events related to cooling and heating have taken high resonance, motivating the scientific community to carry out an intensive research activity, aimed to detect their variability and frequency. In this work, we have investigated about the frequency, the duration, the severity and the intensity of heat and cold waves in a Southern Italy high-altitude region, by analysing the climatological time series collected in Montevergine observatory. Following the guidelines provided by CLIVAR project (Climate and Ocean Variability, Predictability and Change), we have adopted indicators based on percentiles and duration to define a heat wave and cold event. Main results have highlighted a strong and significant positive trend in the last 40 years (1974–2015) in heat waves frequency, severity and intensity. On the contrary, in recent decades, cold wave events have exhibited a significant and positive trend only in intensity. Moreover, through the usage of two Wavelet Analysis tools, the Cross Wavelet Transform and the Wavelet Coherence, we have investigated about the connections between the extreme temperature events occurred in Montevergine and the large-scale atmospheric patterns. The heat wave events have exhibited relevant relationships with the Western European Zonal Circulation and the North Atlantic Oscillation, whereas the variability of cold wave events have shown linkages with the Eastern Mediterranean Pattern and the North Sea Caspian Pattern. In addition, the main features of synoptic patterns that have caused summer heat waves and winter cold waves in Montevergine site are presented.

Highlights

According to the last reports (e.g. IPCC, 2014) provided by the Intergovernmental Panel on Climate Change (IPCC), the last thirty years have been characterized by a significant temperature rise (e.g. Hansen et al, 2006), and by an increasing frequency of extreme events (e.g. Alexander et al, 2006), as a result of climate change.Europe has experienced a lot of extreme events over the last decade, including temperature extremes, named heat and cold waves
We investigate about the variability and trends in the last 130 years of heat (HW) and cold wave (CW) events, by analysing the temperature time series measured in Montevergine observatory (40.56◦ N, 14.43◦ E)
The latter have been estimated for the same frequency bands used for the Continuous Wavelet Transform (CWT) of the Heat Wave events (HW) and CW time series

Summary

Introduction

According to the last reports (e.g. IPCC, 2014) provided by the Intergovernmental Panel on Climate Change (IPCC), the last thirty years have been characterized by a significant temperature rise (e.g. Hansen et al, 2006), and by an increasing frequency of extreme events (e.g. Alexander et al, 2006), as a result of climate change.Europe has experienced a lot of extreme events over the last decade, including temperature extremes, named heat and cold waves. According to the last reports (e.g. IPCC, 2014) provided by the Intergovernmental Panel on Climate Change (IPCC), the last thirty years have been characterized by a significant temperature rise Hansen et al, 2006), and by an increasing frequency of extreme events Europe has experienced a lot of extreme events over the last decade, including temperature extremes, named heat and cold waves. The IPCC Special Report on extreme events (IPCC, 2012) stated that a major increase of warm extreme temperatures in Mediterranean region has been observed in the last three decades. Della-Marta et al (2007), using a dataset consisting of 54 homogenized temperature time series collected in Europe, concluded that the length of heat waves has doubled and that the frequency of hot days has been tripled since 1880

Objectives

Results

Conclusion