Trends of extreme temperature events over the Iberian Peninsula during the 21st century

2020 ◽  
Author(s):  
Francisco Javier Acero ◽  
Javier Portero ◽  
José Agustín García
Keyword(s):  
Iberian Peninsula ◽  
Climate Models ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Kendall Test ◽  
Maximum Temperature ◽  
Positive Trend ◽  
Significant Positive Trend ◽  
Extreme Temperature Events ◽  
Maximum Temperatures

<p>Heat waves are meteorological events exceptionally extremes that are increasing in frequency, duration and intensity. The Iberian Peninsula is characterized in the last decades by an increase in the trend of extreme temperature events and its consequences are important not only for the effects over the population but also for agriculture and biodiversity. The main objective in this study is to analyse future trends over the 21<sup>st</sup> century for extreme temperature using two events: heat waves and warm events. These are defined as the period of at least two consecutive days with temperatures over a certain threshold, the 95th percentile for heat waves and the 75th percentile for warm events. For this purpose, 14 different regionalized dynamic climate projections dataset are used. Firstly, to choose the better climate models, the common period 1961-2000 is used to compare with observational data obtained from SPAIN02 grid dataset. Once the better climate models are selected, trends in both events are analysed for the past (1961-2000) and the future (2011-2099). To estimate trends, Mann-Kendall test and Theil-Sen estimator were applied. Mann-Kendall test returns the significance of the trends for each grid point, while Theil-Sen estimator estimates the value of that trend. Moreover, max-stables processes are used to compare spatial dependence between dynamic projections. The results for the comparison period show that maximum temperature and moderate values of the maximum temperature are increasing smoothly, while low values of maximum temperatures are increasing even faster. This means that the variability of extreme temperature is decreasing, especially in the Mediterranean area of the Iberian Peninsula. For the 21<sup>st</sup> century, results reveal a significant positive trend in low values of the maximum temperatures that increases throughout the century over the whole study area. Warm events show a significant positive trend in frequency and intensity. This trend drastically increases from 2050 onwards.</p>

scholarly journals Analysis of Extreme Temperature Events over the Iberian Peninsula during the 21st Century Using Dynamic Climate Projections Chosen Using Max-Stable Processes

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 506 ◽  
Author(s):  
Javier Portero Serrano ◽  
Francisco Javier Acero Díaz ◽  
José Agustín García García
Keyword(s):  
Iberian Peninsula ◽  
Spatial Dependence ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Mediterranean Area ◽  
Stable Processes ◽  
Climate Projections ◽  
Extreme Temperature Events ◽  
The Mediterranean ◽  
Maximum Temperatures

Due to climate change, the Iberian Peninsula is suffering an increasing trend of extreme temperature events. The main objective of this study is to analyse this trends in frequency, duration and intensity of warm events and heat waves. The datasets used are 14 different regionalized dynamic climate projections. We choose the projections that present a spatial dependence similar to that of observed data. The spatial dependence is calculated by adjusting the data to max-stable processes. The observed data belong to the SPAIN02 grid for the period 1961–2000. We apply the Mann-Kendall test and the Theil-Sen estimator to calculate model trends in the future period (2011–2099). We have studied future extreme temperature events using two different definitions. One varying the threshold for each period and the other keeping it constant. The results show that the variability of maximum temperatures is decreasing for the western region of the Peninsula, while the Mediterranean area will see an increase in this variability. There will be an increase in the frequency of warm events for the southwestern corner of the Peninsula. Also, maximum temperatures will be higher in this area at the end of the century. However, in the Mediterranean region the warm events will last longer. Heat waves will be more frequent throughout the territory and more lasting in the Mediterranean area. We also found that studying extreme events using a varying threshold allows these events to be studied from the point of view of the variability of maximum temperatures, while if the study is carried out maintaining the threshold constant the results will be more direct.

scholarly journals Extreme Temperature Events in Serbia in Relation to Atmospheric Circulation

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1584
Author(s):  
Ivana Tošić ◽  
Suzana Putniković ◽  
Milica Tošić ◽  
Irida Lazić
Keyword(s):  
Atmospheric Circulation ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Daily Maximum ◽  
Absolute Maximum ◽  
Extreme Temperature Events ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Maximum Temperatures ◽  
The Relationship

In this study, extremely warm and cold temperature events were examined based on daily maximum (Tx) and minimum (Tn) temperatures observed at 11 stations in Serbia during the period 1949–2018. Summer days (SU), warm days (Tx90), and heat waves (HWs) were calculated based on daily maximum temperatures, while frost days (FD) and cold nights (Tn10) were derived from daily minimum temperatures. Absolute maximum and minimum temperatures in Serbia rose but were statistically significant only for Tx in winter. Positive trends of summer and warm days, and negative trends of frost days and cold nights were found. A high number of warm events (SU, Tx90, and HWs) were recorded over the last 20 years. Multiple linear regression (MLR) models were applied to find the relationship between extreme temperature events and atmospheric circulation. Typical atmospheric circulation patterns, previously determined for Serbia, were used as predictor variables. It was found that MLR models gave the best results for Tx90, FD, and Tn10 in winter.

scholarly journals A Stepwise-Clustered Simulation Approach for Projecting Future Heat Wave Over Guangdong Province

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiayan Ren ◽  
Guohe Huang ◽  
Yongping Li ◽  
Xiong Zhou ◽  
Jinliang Xu ◽  
...  
Keyword(s):  
Heat Wave ◽  
Climate Models ◽  
Extreme Event ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Global Climate Models ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Simulation Approach

A heat wave is an important meteorological extreme event related to global warming, but little is known about the characteristics of future heat waves in Guangdong. Therefore, a stepwise-clustered simulation approach driven by multiple global climate models (i.e., GCMs) is developed for projecting future heat waves over Guangdong under two representative concentration pathways (RCPs). The temporal-spatial variations of four indicators (i.e., intensity, total intensity, frequency, and the longest duration) of projected heat waves, as well as the potential changes in daily maximum temperature (i.e., Tmax) for future (i.e., 2006–2095) and historical (i.e., 1976–2005) periods, were analyzed over Guangdong. The results indicated that Guangdong would endure a notable increasing annual trend in the projected Tmax (i.e., 0.016–0.03°C per year under RCP4.5 and 0.027–0.057°C per year under RCP8.5). Evaluations of the multiple GCMs and their ensemble suggested that the developed approach performed well, and the model ensemble was superior to any single GCM in capturing the features of heat waves. The spatial patterns and interannual trends displayed that Guangdong would undergo serious heat waves in the future. The variations of intensity, total intensity, frequency, and the longest duration of heat wave are likely to exceed 5.4°C per event, 24°C, 25 days, and 4 days in the 2080s under RCP8.5, respectively. Higher variation of those would concentrate in eastern and southwestern Guangdong. It also presented that severe heat waves with stronger intensity, higher frequency, and longer duration would have significant increasing tendencies over all Guangdong, which are expected to increase at a rate of 0.14, 0.83, and 0.21% per year under RCP8.5, respectively. Over 60% of Guangdong would suffer the moderate variation of heat waves to the end of this century under RCP8.5. The findings can provide decision makers with useful information to help mitigate the potential impacts of heat waves on pivotal regions as well as ecosystems that are sensitive to extreme temperature.

Seasonal analysis of warm extreme events in Serbia from 1949 to 2017

2020 ◽  
Author(s):  
Ivana Tosic ◽  
Suzana Putniković ◽  
Milica Tošić
Keyword(s):  
Extreme Events ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Extreme Temperature Events ◽  
Air Temperatures ◽  
Seasonal Analysis ◽  
Novi Sad

<p>Worldwide studies revealed a general increase in frequency and severity of warm extreme temperature events. In this study, extreme temperature events including Heat waves (HWs) are examined. Extreme indices are calculated based on daily maximum temperature (Tx). The following definitions are employed: SU - number of days with Tx > 25 °C, umber of days with Tx > 90<sup>th</sup> percentile, and WSDI - number of days in intervals of at least six consecutive days for which Tx is higher than the calendar day 90<sup>th</sup> percentile. Daily values of air temperatures from 11 meteorological stations distributed across Serbia were used for the period 1949–2017.</p><p>Trends of extreme temperature events and their frequencies are examined. The period 1949–2017 are characterised by a warming of extreme temperature indices (SU, Tx90, HWs). It is found that maximum air temperatures increased at all stations, but statistically significant at 6 stations in winter, 4 stations in summer and two stations in spring. The average number of SU per station was between 63.1 in Novi Sad to 73.5 in Negotin during the summer season. Significant increase of SU is recorded in summer for 10 out of 11 stations. Positive trends of SU and Tx90 are observed for all stations and seasons, except in Novi Sad. The average number of Tx90 is about 9 for all stations in all seasons. The longest heat waves prevailed in 2012, but the most severe are recorded in 2007. Increasing of warm extreme events in Serbia are in agreement with studies for different regions of the world.</p>

scholarly journals Assessment of Seasonal Variability of Extreme Temperature In Mainland China Under Climate Change

2021 ◽  
Author(s):  
Weixiong Yan ◽  
Junfang Zhao ◽  
Jianping Li ◽  
Yuanxia Wang
Keyword(s):  
Climate Change ◽  
Seasonal Cycle ◽  
Mainland China ◽  
Extreme Temperature ◽  
Maximum Temperature ◽  
Positive Trend ◽  
The Tibetan Plateau ◽  
Extreme Temperatures ◽  
Significant Positive Trend ◽  
Temperature Seasonality

Abstract Grain yield may be affected in the future by climate change. Some studies have suggested that variations in the seasonal cycle of temperature and season onset could affect the efficiency in the use of radiation by plants, which would then affect yield. However, the study of the temporal variation in extreme climatic variables is not sufficient in China. Therefore, this article evaluates the distribution of extreme temperature seasonality trends in mainland China, describes the trends in the seasonal cycle, and detects changes in extreme temperature characterized by the number of hot days (HD), and frost days (FD) and the frequency of warm days (Tx90p), cold days (Tx10p), warm nights (Tn90p) and cold nights (Tn10p). All data are from the EAR5 reanalysis for the 1979-2020 periods.The results show a statistically significant positive trend in the annual average amplitudes (A0) of extreme temperatures. The change in Txmax was the smallest, but it also accounted for 84.5% of the total area. The annual amplitude (A1) and phase (F1) experienced less variation than A0 for extreme temperatures in mainland China. A1 of the maximum temperature decreased significantly on the Tibetan Plateau and increased significantly in the Tianshan Mountains and Jungar Basin (mainly Taxman). F1 of the maximum temperature exhibit a negative trend in approximately 30% of mainland China, and the trend appeared in some regions except in the Northeast and Southwest. Although A1 of the minimum temperature was not as large as that of the maximum temperature, its distribution was very characteristic and it was almost bounded by the 400 mm isohyet, increasing in the Northwest and decreasing in the Southeast. In terms of the number of days, there was an increase in HD, Tx90p, and Tn90p, as well as a decrease in FD, Tx10p, and Tn10p. This number of days also indicates that temperature has increased over mainland China in the past 42 years.

scholarly journals Climate Change Projections of Extreme Temperatures for the Iberian Peninsula

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 229 ◽  
Author(s):  
Carolina Viceto ◽  
Susana Cardoso Pereira ◽  
Alfredo Rocha
Keyword(s):  
Iberian Peninsula ◽  
Heat Wave ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Extreme Heat ◽  
Recovery Factor ◽  
Maximum Temperature ◽  
Weather Research And Forecasting ◽  
Temperature Changes ◽  
Temperature Thresholds

The comprehensive characterization of heat waves and extreme hot days is fundamental for policymakers due to its vast implications for human health. This study evaluates extreme temperature changes over the Iberian Peninsula for the present climate and future projections, considering extreme temperature indices, cold/heat waves, and a recovery factor, using the Weather Research and Forecasting model. The projected temperatures show an increase of over 6 °C. An increase in the number of summer days and tropical nights and a decrease in frost days is expected. The number of heat waves and their duration and intensity are expected to increase. The number of heat wave days are expected to increase, with much of the average summer season being under heat wave conditions. The recovery factor is expected to decrease. Cold spells are projected to decrease in terms of number, intensity, duration, and number of spell days, whereas the recovery factor is expected to increase. Heat wave analysis was combined with maximum temperature thresholds to isolate extreme heat waves. The results show an increase in extreme heat wave days, with regions experiencing over 10 heat wave days with maximum temperature surpassing 45 °C for the long-term future.

scholarly journals Extreme heat in India and anthropogenic climate change

2018 ◽  
Vol 18 (1) ◽  
pp. 365-381 ◽  
Author(s):  
Geert Jan van Oldenborgh ◽  
Sjoukje Philip ◽  
Sarah Kew ◽  
Michiel van Weele ◽  
Peter Uhe ◽  
...  
Keyword(s):  
Air Pollution ◽  
Global Warming ◽  
Health Effects ◽  
Climate Models ◽  
Decadal Variability ◽  
Heat Waves ◽  
Health Impact ◽  
Heat Index ◽  
Maximum Temperature ◽  
Surface Cooling

Abstract. On 19 May 2016 the afternoon temperature reached 51.0 °C in Phalodi in the northwest of India – a new record for the highest observed maximum temperature in India. The previous year, a widely reported very lethal heat wave occurred in the southeast, in Andhra Pradesh and Telangana, killing thousands of people. In both cases it was widely assumed that the probability and severity of heat waves in India are increasing due to global warming, as they do in other parts of the world. However, we do not find positive trends in the highest maximum temperature of the year in most of India since the 1970s (except spurious trends due to missing data). Decadal variability cannot explain this, but both increased air pollution with aerosols blocking sunlight and increased irrigation leading to evaporative cooling have counteracted the effect of greenhouse gases up to now. Current climate models do not represent these processes well and hence cannot be used to attribute heat waves in this area. The health effects of heat are often described better by a combination of temperature and humidity, such as a heat index or wet bulb temperature. Due to the increase in humidity from irrigation and higher sea surface temperatures (SSTs), these indices have increased over the last decades even when extreme temperatures have not. The extreme air pollution also exacerbates the health impacts of heat. From these factors it follows that, from a health impact point of view, the severity of heat waves has increased in India. For the next decades we expect the trend due to global warming to continue but the surface cooling effect of aerosols to diminish as air quality controls are implemented. The expansion of irrigation will likely continue, though at a slower pace, mitigating this trend somewhat. Humidity will probably continue to rise. The combination will result in a strong rise in the temperature of heat waves. The high humidity will make health effects worse, whereas decreased air pollution would decrease the impacts.

scholarly journals Assessment of Seasonal Variability of Extreme Temperature in Mainland China under Climate Change

2021 ◽  
Vol 13 (22) ◽  
pp. 12462
Author(s):  
Wei-Xiong Yan ◽  
Jun-Fang Zhao ◽  
Jian-Ping Li ◽  
Yun-Xia Wang
Keyword(s):  
Annual Cycle ◽  
Seasonal Cycle ◽  
Mainland China ◽  
Extreme Temperature ◽  
Spatial Characteristic ◽  
Maximum Temperature ◽  
Positive Trend ◽  
Extreme Temperatures ◽  
Annual Average ◽  
Temperature Seasonality

Some studies have suggested that variations in the seasonal cycle of temperature and season onset could affect the efficiency in the use of radiation by plants, which would then affect yield. However, the study of the temporal variation in extreme climatic variables is not sufficient in China. Using seasonal trend analysis (STA), this article evaluates the distribution of extreme temperature seasonality trends in mainland China, describes the trends in the seasonal cycle, and detects changes in extreme temperature characterized by the number of hot days (HD) and frost days (FD), the frequency of warm days (TX90p), cold days (TX10p), warm nights (TN90p), and cold nights (TN10p). The results show a statistically significant positive trend in the annual average amplitudes of extreme temperatures. The amplitude and phase of the annual cycle experience less variation than that of the annual average amplitude for extreme temperatures. The phase of the annual cycle in maximum temperature mainly shows a significant negative trend, accounting for approximately 30% of the total area of China, which is distributed across the regions except for northeast and southwest. The amplitude of the annual cycle indicates that the minimum temperature underwent slightly greater variation than the maximum temperature, and its distribution has a spatial characteristic that is almost bounded by the 400 mm isohyet, increasing in the northwest and decreasing in the southeast. In terms of the extreme air temperature indices, HD, TX90p, and TN90p show an increasing trend, FD, TX10p, and TN10p show a decreasing trend. They are statistically significant (p < 0.05). This number of days also suggests that temperature has increased over mainland China in the past 42 years.

scholarly journals Future Temperature Extremes Will Be More Harmful: A New Critical Factor for Improved Forecasts

2019 ◽  
Vol 16 (20) ◽  
pp. 4015 ◽  
Author(s):  
Costas A. Varotsos ◽  
Yuri A. Mazei
Keyword(s):  
Climate Change ◽  
Temperature Change ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Well Being ◽  
Early Warning Systems ◽  
Extreme Weather Events ◽  
Anthropogenic Activity ◽  
Extreme Temperature Events ◽  
The Past

There is increasing evidence that extreme weather events such as frequent and intense cold spells and heat waves cause unprecedented deaths and diseases in both developed and developing countries. Thus, they require extensive and immediate research to limit the risks involved. Average temperatures in Europe in June–July 2019 were the hottest ever measured and attributed to climate change. The problem, however, of a thorough study of natural climate change is the lack of experimental data from the long past, where anthropogenic activity was then very limited. Today, this problem can be successfully resolved using, inter alia, biological indicators that have provided reliable environmental information for thousands of years in the past. The present study used high-resolution quantitative reconstruction data derived from biological records of Lake Silvaplana sediments covering the period 1181–1945. The purpose of this study was to determine whether a slight temperature change in the past could trigger current or future intense temperature change or changes. Modern analytical tools were used for this purpose, which eventually showed that temperature fluctuations were persistent. That is, they exhibit long memory with scaling behavior, which means that an increase (decrease) in temperature in the past was always followed by another increase (decrease) in the future with multiple amplitudes. Therefore, the increase in the frequency, intensity, and duration of extreme temperature events due to climate change will be more pronounced than expected. This will affect human well-being and mortality more than that estimated in today’s modeling scenarios. The scaling property detected here can be used for more accurate monthly to decadal forecasting of extreme temperature events. Thus, it is possible to develop improved early warning systems that will reduce the public health risk at local, national, and international levels.

scholarly journals Heat waves in Africa 1981–2015, observations and reanalysis

2017 ◽  
Vol 17 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Guido Ceccherini ◽  
Simone Russo ◽  
Iban Ameztoy ◽  
Andrea Francesco Marchese ◽  
Cesar Carmona-Moreno
Keyword(s):  
Heat Wave ◽  
Heat Waves ◽  
Extreme Temperature ◽  
Reanalysis Data ◽  
Maximum Temperature ◽  
Wave Analysis ◽  
Land Area ◽  
Spatial Coverage ◽  
Temperature Records ◽  
Numerical Index

Abstract. The purpose of this article is to show the extreme temperature regime of heat waves across Africa over recent years (1981–2015). Heat waves have been quantified using the Heat Wave Magnitude Index daily (HWMId), which merges the duration and the intensity of extreme temperature events into a single numerical index. The HWMId enables a comparison between heat waves with different timing and location, and it has been applied to maximum and minimum temperature records. The time series used in this study have been derived from (1) observations from the Global Summary of the Day (GSOD) and (2) reanalysis data from ERA-Interim. The analysis shows an increasing number of heat waves of both maxima and minima temperatures in the last decades. Results from heat wave analysis of maximum temperature (HWMIdtx) indicate an increase in intensity and frequency of extreme events. Specifically, from 1996 onwards it is possible to observe HWMIdtx spread with the maximum presence during 2006–2015. Between 2006 and 2015 the frequency (spatial coverage) of extreme heat waves had increased to 24.5 observations per year (60.1 % of land cover), as compared to 12.3 per year (37.3 % of land area) in the period from 1981 to 2005 for GSOD stations (reanalysis).

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