Recent trends in daily temperature extremes over northeastern Spain (1960–2006)

Spatial and temporal characteristics of extreme temperature events in northeastern Spain have been investigated. The analysis is based on long-term, high-quality, and homogenous daily maximum and minimum temperature of 128 observatories spanning the period from 1960 to 2006. A total of 21 indices we...

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Main Authors: A. El Kenawy, J. I. López-Moreno, S. M. Vicente-Serrano
Format: Article
Language:English
Published: Copernicus Publications 2011-09-01
Series:Natural Hazards and Earth System Sciences
Online Access:http://www.nat-hazards-earth-syst-sci.net/11/2583/2011/nhess-11-2583-2011.pdf
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author A. El Kenawy
J. I. López-Moreno
S. M. Vicente-Serrano
author_facet A. El Kenawy
J. I. López-Moreno
S. M. Vicente-Serrano
author_sort A. El Kenawy
collection DOAJ
description Spatial and temporal characteristics of extreme temperature events in northeastern Spain have been investigated. The analysis is based on long-term, high-quality, and homogenous daily maximum and minimum temperature of 128 observatories spanning the period from 1960 to 2006. A total of 21 indices were used to assess changes in both the cold and hot tails of the daily temperature distributions. The presence of trends in temperature extremes was assessed by means of the Mann-Kendall test. However, the autocorrelation function (ACF) and a bootstrap methodology were used to account for the influence of serial correlation and cross-correlation on the trend assessment. In general, the observed changes are more prevalent in hot extremes than in cold extremes. This finding can largely be linked to the increase found in the mean maximum temperature during the last few decades. The results indicate a significant increase in the frequency and intensity of most of the hot temperature extremes. An increase in warm nights (TN90p: 3.3 days decade<sup>−1</sup>), warm days (TX90p: 2.7 days decade<sup>−1</sup>), tropical nights (TR20: 0.6 days decade<sup>−1</sup>) and the annual high maximum temperature (TXx: 0.27 °C decade<sup>−1</sup>) was detected in the 47-yr period. In contrast, most of the indices related to cold temperature extremes (e.g. cold days (TX10p), cold nights (TN10p), very cold days (TN1p), and frost days (FD0)) demonstrated a decreasing but statistically insignificant trend. Although there is no evidence of a long-term trend in cold extremes, significant interdecadal variations were noted. Almost no significant trends in temperature variability indices (e.g. diurnal temperature range (DTR) and growing season length (GSL)) are detected. Spatially, the coastal areas along the Mediterranean Sea and the Cantabrian Sea experienced stronger warming compared with mainland areas. Given that only few earlier studies analyzed observed changes in temperature extremes at fine spatial resolution across the Iberian Peninsula, the results of this work can improve our understanding of climatology of temperature extremes. Also, these findings can have different hydrological, ecological and agricultural implications (e.g. crop yields, energy consumption, land use planning and water resources management).
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spelling doaj.art-dd25df30cf14407a8753c737b5b1efe62022-12-21T19:10:36ZengCopernicus PublicationsNatural Hazards and Earth System Sciences1561-86331684-99812011-09-011192583260310.5194/nhess-11-2583-2011Recent trends in daily temperature extremes over northeastern Spain (1960–2006)A. El KenawyJ. I. López-MorenoS. M. Vicente-SerranoSpatial and temporal characteristics of extreme temperature events in northeastern Spain have been investigated. The analysis is based on long-term, high-quality, and homogenous daily maximum and minimum temperature of 128 observatories spanning the period from 1960 to 2006. A total of 21 indices were used to assess changes in both the cold and hot tails of the daily temperature distributions. The presence of trends in temperature extremes was assessed by means of the Mann-Kendall test. However, the autocorrelation function (ACF) and a bootstrap methodology were used to account for the influence of serial correlation and cross-correlation on the trend assessment. In general, the observed changes are more prevalent in hot extremes than in cold extremes. This finding can largely be linked to the increase found in the mean maximum temperature during the last few decades. The results indicate a significant increase in the frequency and intensity of most of the hot temperature extremes. An increase in warm nights (TN90p: 3.3 days decade<sup>−1</sup>), warm days (TX90p: 2.7 days decade<sup>−1</sup>), tropical nights (TR20: 0.6 days decade<sup>−1</sup>) and the annual high maximum temperature (TXx: 0.27 °C decade<sup>−1</sup>) was detected in the 47-yr period. In contrast, most of the indices related to cold temperature extremes (e.g. cold days (TX10p), cold nights (TN10p), very cold days (TN1p), and frost days (FD0)) demonstrated a decreasing but statistically insignificant trend. Although there is no evidence of a long-term trend in cold extremes, significant interdecadal variations were noted. Almost no significant trends in temperature variability indices (e.g. diurnal temperature range (DTR) and growing season length (GSL)) are detected. Spatially, the coastal areas along the Mediterranean Sea and the Cantabrian Sea experienced stronger warming compared with mainland areas. Given that only few earlier studies analyzed observed changes in temperature extremes at fine spatial resolution across the Iberian Peninsula, the results of this work can improve our understanding of climatology of temperature extremes. Also, these findings can have different hydrological, ecological and agricultural implications (e.g. crop yields, energy consumption, land use planning and water resources management).http://www.nat-hazards-earth-syst-sci.net/11/2583/2011/nhess-11-2583-2011.pdf
spellingShingle A. El Kenawy
J. I. López-Moreno
S. M. Vicente-Serrano
Recent trends in daily temperature extremes over northeastern Spain (1960–2006)
Natural Hazards and Earth System Sciences
title Recent trends in daily temperature extremes over northeastern Spain (1960–2006)
title_full Recent trends in daily temperature extremes over northeastern Spain (1960–2006)
title_fullStr Recent trends in daily temperature extremes over northeastern Spain (1960–2006)
title_full_unstemmed Recent trends in daily temperature extremes over northeastern Spain (1960–2006)
title_short Recent trends in daily temperature extremes over northeastern Spain (1960–2006)
title_sort recent trends in daily temperature extremes over northeastern spain 1960 2006
url http://www.nat-hazards-earth-syst-sci.net/11/2583/2011/nhess-11-2583-2011.pdf
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