scholarly journals The occurrence of heat waves in Europe and their circulation conditions

Geografie ◽  
2019 ◽  
Vol 124 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Arkadiusz M. Tomczyk ◽  
Ewa Bednorz ◽  
Marek Półrolniczak
Keyword(s):  
Sea Level ◽  
Heat Wave ◽  
Air Temperature ◽  
Atmospheric Pressure ◽  
Geopotential Height ◽  
Heat Waves ◽  
Daily Maximum ◽  
Isobaric Surface ◽  
Hot Days ◽  
Maximum Air Temperature

The objective of the paper was to characterize the occurrence of heat waves in Europe between 1976 and 2015 and to determine circulation conditions causing their occurrence. The heat waves were recognized as a sequence of at least 5 consecutive hot days. The hot day was defined as a day on which daily maximum air temperature was higher than 95th percentile of all the values in the analyzed period. The conducted research showed an increase in the number of heat waves and their duration in the analyzed period. The longest heat wave occurred in 2010, in Moscow, which lasted 45 days. The most intense changes were observed in the eastern and south-eastern regions. The occurrence of heat waves was mainly connected with positive anomalies of atmospheric pressure at sea level, geopotential height of 500 hPa, and temperature on isobaric surface 850 hPa.

Micro-climatological influences on temperature condition in an old people’s home in Helsinki, Finland, caused by extended heat-waves 

2021 ◽  
Author(s):  
Achim Drebs ◽  
Tim Sinsel ◽  
Kirsti Jylhä
Keyword(s):  
Air Temperature ◽  
Heat Waves ◽  
Daily Maximum ◽  
Old People ◽  
Concrete Walls ◽  
Meteorological Forcing ◽  
Clear Sky ◽  
Wave Event ◽  
Construction Type ◽  
Maximum Air Temperature

<p>In our research we describe the micro-climatological influences of two heat-waves around and the air temperature development in a certain old people’s home in Helsinki, Finland. The stand-alone six-storey concrete building was erected in the late 1970’s and represents the prevailing construction type of this area. The building is located on a slightly southwards declining slope.</p><p>The first simulation used real meteorological forcing-data from the heat-wave event in summer 2018, which lasted from July, 13<sup>th</sup> until August, 5<sup>th</sup>. In this period the daily maximum air temperature reached almost every day 25 °C and more, sometimes even more than 30 °C. All air temperature, wind, humidity, and solar radiation (cloudiness) measurements were conducted at a near-by synoptical weather station.</p><p>The second simulation used fourteen-day constructed meteorological forcing-data, based on a clear-sky, slowly increasing air temperature, higher than normal humidity, and low wind conditions assumption starting on July, 13<sup>th</sup> (day 194 of the year).</p><p>We used the holistic ENVI-met simulation soft-ware to simulate the physical environment around the old people’s home and especially the energy fluxes inside the concrete walls to explain the needs for cooling demands.</p><p>The research is part of the HEATCLIM-project financed by the Academy of Finland Science Program CLIHE (2020-2023).</p>

Analysis of the extreme heat events in Iran

2017 ◽  
Vol 9 (4) ◽  
pp. 418-432 ◽  
Author(s):  
Hojjatollah Yazdanpanah ◽  
Josef Eitzinger ◽  
Marina Baldi
Keyword(s):  
Trend Analysis ◽  
Heat Wave ◽  
Heat Waves ◽  
Temporal Variations ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Positive Trend ◽  
Content Type ◽  
Hot Days

Purpose The purpose of this paper is to assess the spatial and temporal variations of extreme hot days (H*) and heat wave frequencies across Iran. Design/methodology/approach The authors used daily maximum temperature (Tmax) data of 27 synoptic stations in Iran. These data were standardized using the mean and the standard deviation of each day of the year. An extreme hot day was defined when the Z score of daily maximum temperature of that day was equal or more than a given threshold fixed at 1.7, while a heat wave event was considered to occur when the Z score exceeds the threshold for at least three continuous days. According to these criteria, the annual frequency of extreme hot days and the number of heat waves were determined for all stations. Findings The trend analysis of H* shows a positive trend during the past two decades in Iran, with the maximum number of H* (110 cases) observed in 2010. A significant trend of the number of heat waves per year was also detected during 1991-2013 in all the stations. Overall, results indicate that Iran has experienced heat waves in recent years more often than its long-term average. There will be more frequent and intense hot days and heat waves across Iran until 2050, due to estimated increase of mean air temperature between 0.5-1.1 and 0.8-1.6 degree centigrade for Rcp2.6 and Rcp8.8 scenarios, respectively. Originality/value The trend analysis of hot days and heat wave frequencies is a particularly original aspect of this paper. It is very important for policy- and decision-makers especially in agriculture and health sectors of Iran to make some adaptation strategies for future frequent and intense hot days over Iran.

scholarly journals Analysis of the episodes of tropospheric ozone concentration in relation with hot days and heat waves in Warsaw

2018 ◽  
Vol 57 ◽  
pp. 02010 ◽  
Author(s):  
Katarzyna Rozbicka ◽  
Tomasz Rozbicki
Keyword(s):  
Air Temperature ◽  
Ozone Concentration ◽  
Tropospheric Ozone ◽  
Heat Waves ◽  
Maximum Temperature ◽  
Limit Value ◽  
Average Maximum ◽  
Hot Days ◽  
Average Maximum Temperature ◽  
Maximum Air Temperature

The study presents the characteristics of the occurrence of smog episodes - days with exceeded the limit value of 8-hour tropospheric ozone concentration (120 μg.m-3) with the occurrence of hot days (maximum air temperature greater than 25°C), very hot (maximum air temperature greater than 30°C) and heat waves during 13-year period 2004-2016 in the area of Warsaw, Poland. In the analyzed period, the average number of hot days was 45, and very hot days was 8. The highest number of these days occurred in 2015, 54 and 20 days respectively. Heat waves were short and lasted usually 3-4 days. The highest number of them was recorded in 2010 and 2015 (14 days). The highest ozone concentration value 189 μg.m-3was recorded on 28 May 2005, thus exceeding the information threshold (180 μg.m-3for the value of 1 hour ozone concentration). However, the number of days with the exceeded limit value of ozone concentration was not in any year exceeded the target value, i.e. 25 days in a calendar year. The relatively stronger relationship (R=0.513) in comparison to others obtained between average maximum temperature during LTO exceedance days and average ozone concentration during these days but it was not statistically significant.

scholarly journals Atmospheric circulation during heat waves in Eastern Europe

Geografie ◽  
2017 ◽  
Vol 122 (2) ◽  
pp. 121-146 ◽  
Author(s):  
Arkadiusz M. Tomczyk
Keyword(s):  
High Pressure ◽  
Eastern Europe ◽  
Sea Level ◽  
Heat Wave ◽  
Geopotential Height ◽  
Heat Waves ◽  
Maximum Temperature ◽  
Pressure System ◽  
Sea Level Pressure ◽  
The One

This article aims to describe heat waves in Eastern Europe and to determine the synoptic situations which cause them. In this article, a hot day is defined as the one with a maximum temperature above the 95th percentile of all the values in the analysed period, and a heat wave is considered as a sequence of at least 5 such days. In the analysed period and within the investigated area, from 24 (Kaliningrad) to 55 (Kharkiv) heat waves were observed. The longest heat wave was recorded in Moscow in 2010, lasting as many as 45 days. In the analysed period, an increase in frequency and length of heat waves was observed within the analysed area. The occurrence of heat waves was connected with a high pressure system located over the eastern part of the continent, during which positive anomalies of sea level pressure and the 500 hPa geopotential height as well as positive T850 anomalies were recorded.

scholarly journals Evaluating sub-seasonal heatwave reforecasts of the ECMWF over Europe

2021 ◽  
Author(s):  
Natalia Korhonen ◽  
Otto Hyvärinen ◽  
Matti Kämäräinen ◽  
Kirsti Jylhä
Keyword(s):  
Heat Wave ◽  
Heat Waves ◽  
Lead Times ◽  
Weather Forecasts ◽  
Wave Forecast ◽  
Extended Range ◽  
Hot Days ◽  
Medium Range ◽  
Summer Temperatures

<p>Severe heatwaves have harmful impacts on ecosystems and society. Early warning of heat waves help with decreasing their harmful impact. Previous research shows that the Extended Range Forecasts (ERF) of the European Centre for Medium-Range Weather Forecasts (ECMWF) have over Europe a somewhat higher reforecast skill for extreme hot summer temperatures than for long-term mean temperatures. Also it has been shown that the reforecast skill of the ERFs of the ECMWF was strongly increased by the most severe heat waves (the European heatwave 2003 and the Russian heatwave 2010).</p><p>Our aim is to be able to estimate the skill of a heat wave forecast at the time the forecast is given. For that we investigated the spatial and temporal reforecast skill of the ERFs of the ECMWF to forecast hot days (here defined as a day on which the 5 days running mean surface temperature is above its summer 90<sup>th</sup> percentile) in the continental Europe in summers 2000-2019. We used the ECMWF 2-meter temperature reforecasts and verified them against the ERA5 reanalysis. The skill of the hot day reforecasts was estimated by the symmetric extremal dependence index (SEDI) which considers both hit rates and false alarm rates of the hot day forecasts. Further, we investigated the skill of the heatwave reforecasts based on at which time steps of the forecast the hot days were forecasted. We found that on the mesoscale (horizontal scale of ~500 km) the ERFs of the ECMWF were most skillful in predicting the life cycle of a heat wave (lasting up to 25 days) about a week before its start and during its course. That is, on the mesoscale those reforecasts, in which hot day(s) were forecasted to occur during the first 7…11 days, were more skillful on lead times up to 25 days than the rest of the heat wave forecasts. This finding is valuable information, e.g., in the energy and health sectors while preparing for a coming heat wave.</p><p>The work presented here is part of the research project HEATCLIM (Heat and health in the changing climate) funded by the Academy of Finland.</p>

Can climate adaptation solutions fix the urban heat island? An assessment of the thermal conditions during heat waves in Vienna impacted by climate change and urban development scenarios for the mid-21st-century

2020 ◽  
Author(s):  
Paul Hamer ◽  
Heidelinde Trimmel ◽  
Philipp Weihs ◽  
Stéphanie Faroux ◽  
Herbert Formayer ◽  
...  
Keyword(s):  
Climate Change ◽  
Urban Heat Island ◽  
Heat Wave ◽  
Air Temperature ◽  
Urban Areas ◽  
Climate Adaptation ◽  
Heat Waves ◽  
Heat Island ◽  
Human Thermal Comfort ◽  
Urban Heat

<p>Climate change threatens to exacerbate existing problems in urban areas arising from the urban heat island. Furthermore, expansion of urban areas and rising urban populations will increase the numbers of people exposed to hazards in these vulnerable areas. We therefore urgently need study of these environments and in-depth assessment of potential climate adaptation measures.</p><p>We present a study of heat wave impacts across the urban landscape of Vienna for different future development pathways and for both present and future climatic conditions. We have created two different urban development scenarios that estimate potential urban sprawl and optimized development concerning future building construction in Vienna and have built a digital representation of each within the Town Energy Balance (TEB) urban surface model. In addition, we select two heat waves of similar frequency of return representative for present and future conditions (following the RCP8.5 scenario) of the mid 21<sup>st</sup> century and use the Weather Research and Forecasting Model (WRF) to simulate both heat wave events. We then couple the two representations urban Vienna in TEB with the WRF heat wave simulations to estimate air temperature, surface temperatures and human thermal comfort during the heat waves. We then identify and apply a set of adaptation measures within TEB to try to identify potential solutions to the problems associated with the urban heat island.</p><p>Global and regional climate change under the RCP8.5 scenario causes the future heat wave to be more severe showing an increase of daily maximum air temperature in Vienna by 7 K; the daily minimum air temperature will increase by 2-4 K. We find that changes caused by urban growth or densification mainly affect air temperature and human thermal comfort local to where new urbanisation takes place and does not occur significantly in the existing central districts.</p><p>Exploring adaptation solutions, we find that a combination of near zero-energy standards and increasing albedo of building materials on the city scale accomplishes a maximum reduction of urban canyon temperature of 0.9 K for the minima and 0.2 K for the maxima. Local scale changes of different adaption measures show that insulation of buildings alone increases the maximum wall surface temperatures by more than 10 K or the maximum mean radiant temperature (MRT) in the canyon by 5 K.  Therefore, additional adaptation to reduce MRT within the urban canyons like tree shade are needed to complement the proposed measures.</p><p>This study concludes that the rising air temperatures expected by climate change puts an unprecedented heat burden on Viennese inhabitants, which cannot easily be reduced by measures concerning buildings within the city itself. Additionally, measures such as planting trees to provide shade, regional water sensitive planning and global reduction of greenhouse gas emissions in order to reduce temperature extremes are required.</p><p>We are now actively seeking to apply this set of tools to a wider set of cases in order to try to find effective solutions to projected warming resulting from climate change in urban areas.</p>

scholarly journals Ondas de calor nas capitais do Sul do Brasil e Montevidéu - Uruguai (Heat waves in the capitals of southern Brazil and Montevideo - Uruguay)

2019 ◽  
Vol 12 (4) ◽  
pp. 1259
Author(s):  
Rafael Brito Silveira ◽  
Maikon Passos Amilton Alves ◽  
Marcelo Barreiro ◽  
Daniel Pires Bitencourt
Keyword(s):  
Heat Wave ◽  
Air Temperature ◽  
Heat Waves ◽  
Kendall Test ◽  
Temperature Data ◽  
Extreme Weather Events ◽  
Southern Brazil ◽  
Porto Alegre ◽  
Significance Level ◽  
Weather Events

Múltiplas partes do globo, possivelmente, passarão a ter dias e noites mais quentes e, com a elevação das temperaturas globais, há tendências de acréscimo do risco de eventos atmosféricos extremos, tais como as ondas de calor. O objetivo principal desse estudo foi verificar as características gerais das ondas de calor nas três capitais da região Sul do Brasil (Curitiba, Florianópolis e Porto Alegre) e também em Montevidéu, capital do Uruguai. Esta análise baseou-se nos parâmetros: frequência, intensidade, duração e suas respectivas tendências. As ondas de calor foram identificadas em uma série de 30 anos de dados diários de temperatura média do ar. As análises de tendência foram averiguadas por meio do teste de Mann-Kendall a um nível de significância de α = 5%. Os resultados mostraram que todos os parâmetros nas quatro cidades apresentam tendências estatisticamente significativas e, com exceção da duração em Montevidéu, todas as demais são positivas. Para além do âmbito das tendências, analisando os parâmetros, comparativamente, conclui-se que Porto Alegre apresenta maior destaque nas médias. Além disto, afirma-se que o inverno é a estação com maior frequência de ondas de calor para todas as cidades.  A B S T R A C TMultiple parts of the globe are likely to have warmer days and nights, and with rising global temperatures, there is a tendency to increase the risk of extreme weather events, such as heat waves. The main objective of this study was to verify the general characteristics of heat waves in the three capitals of southern Brazil (Curitiba, Florianópolis and Porto Alegre) and also in Montevideo, capital of Uruguay. This analysis was based on the parameters: frequency, intensity, duration and their respective trends. Heat waves were identified in a series of 30 years of daily average air temperature data. Trend analyzes were performed using the Mann-Kendall test at a significance level of α = 5%. The results showed that all the parameters in the four cities present statistically significant trends and, except for the duration in Montevideo, all the others are positive. In addition to the scope of the trends, analyzing the parameters, comparatively, it is concluded that Porto Alegre presents greater prominence in the averages. In addition, it is claimed that winter is the season with the highest frequency of heat waves for all cities.Keywords: heat wave, subtropical, capitals, trends, parameters.

scholarly journals Trends in heat stress over Europe over the 20th century

2021 ◽  
Author(s):  
Joakim Kjellsson ◽  
Nils Niebaum ◽  
Robin Pilch Kedzierski
Keyword(s):  
Heat Stress ◽  
20Th Century ◽  
Heat Wave ◽  
Air Temperature ◽  
Heat Waves ◽  
Dew Point ◽  
Stress Index ◽  
Internal Climate Variability ◽  
Air Temperatures ◽  
Using Data

<p>We investigate how European heat waves and their associated heat stress on humans have changed over the 20th century. We find that the heat stress has increased, even in regions where heat waves have not become warmer. As heat stress increases over wide areas of Europe there is also an increase in the total population affected by the heat stress. </p><p>Heat waves pose a serious health risk to humans by reducing our ability to shed heat. We have studied the occurrence and intensity of heat waves as well as a heat stress index based on simplified wet-bulb globe temperature using data from ERA-20C reanalysis 1900-2010. Over the 110 years of data we find an overall warming of the air temperatures and dew point. The 98th percentile of both air temperature has increased by more than 1.5°C over large areas of Europe. </p><p>We find an overall increase in heat wave days per year as well as an increase of air temperature during heat waves over most of Europe. As such, many densely populated areas exhibit increased heat stress during heat waves. For example, the mean heat stress during heat wave days over Paris has increased by one level, from “alert” in 1900-1930 to “caution” in 1980-2010. The fraction of the population exposed to heat waves has increased by 10%/century in central Europe and 25%/century over the Mediterranean. </p><p>We find more heat waves during 1920 - 1950, which may be related to the positive phase of the Atlantic Multidecadal Variation (AMV). This suggests that the heat stress during European heat waves may also be influenced by internal climate variability, and large-ensemble model simulations may be used to disentangle the effects of natural variability and anthropogenic forcing.</p>

scholarly journals Climate trends in the municipality of Pelotas, state of Rio Grande do Sul, Brazil

2015 ◽  
Vol 35 (4) ◽  
pp. 769-777 ◽  
Author(s):  
Izabele B. Kruel ◽  
Monica C. Meschiatti ◽  
Gabriel C. Blain ◽  
Ana M. H. de Ávila
Keyword(s):  
Air Temperature ◽  
Rio Grande ◽  
Location Parameter ◽  
Temperature Series ◽  
Likelihood Method ◽  
Daily Maximum ◽  
Rio Grande Do Sul ◽  
The Mean ◽  
Maximum Air Temperature ◽  
Over Time

ABSTRACT Changes in the frequency of occurrence of extreme weather events have been pointed out as a likely impact of global warming. In this context, this study aimed to detect climate change in series of extreme minimum and maximum air temperature of Pelotas, State of Rio Grande do Sul, (1896 - 2011) and its influence on the probability of occurrence of these variables. We used the general extreme value distribution (GEV) in its stationary and non-stationary forms. In the latter case, GEV parameters are variable over time. On the basis of goodness-of-fit tests and of the maximum likelihood method, the GEV model in which the location parameter increases over time presents the best fit of the daily minimum air temperature series. Such result describes a significant increase in the mean values of this variable, which indicates a potential reduction in the frequency of frosts. The daily maximum air temperature series is also described by a non-stationary model, whose location parameter decreases over time, and the scale parameter related to sample variance rises between the beginning and end of the series. This result indicates a drop in the mean of daily maximum air temperature values and increased dispersion of the sample data.

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