Climate Variability and Urbanization in Athens

Philandras, C. M.; Metaxas, D. A.; Nastos, Panagiotis T.

doi:10.1007/s007040050092

Cited by 86 publications

(59 citation statements)

References 9 publications

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“…The increase in human thermal dis- comfort noted here for Athens after the early 1980s matches with similar trends during the same period found by others either for mean summer air temperature or for the frequency of extreme high temperature events, which have been reported to be a result of the predominance of warmer air masses in the lower troposphere over the southern Balkans and the intensification of urbanization in the city of Athens over recent years (e.g. see Philandras et al, 1999;Lolis et al, 2002;Kioutsioukis et al, 2010;Founda, 2011).…”

Section: Resultssupporting

confidence: 90%

“…The increase of the mean temperature observed for Athens started in the middle 1980s (Founda, 2011). Furthermore, the continuous process of urbanization and the associated urban heat island effect constitutes a second contributor to the local warming and modification of climate characteristics, especially in summer (Philandras et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

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Climatic characteristics of summer human thermal discomfort in Athens and its connection to atmospheric circulation

Bartzokas

Lolis

Kassomenos

et al. 2013

Nat. Hazards Earth Syst. Sci.

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Abstract. The climate characteristics of summer human thermal discomfort in Athens and its connection to atmospheric circulation are studied for the period 1954–2012. The human thermal discomfort is examined in terms of the Predicted Mean Vote (PMV) discomfort index for calm and light wind (3 ms-1) conditions. Its inter-annual variability is characterised by a significant increase from the middle 1980s to the end of the study period. The onset and the cessation of the discomfort period are found to take place around the beginning of July and the end of August respectively, but from middle 1980s the dates of onset and cessation have slightly moved earlier and later, respectively, leading to a longer summer discomfort period. The connection between human thermal discomfort and atmospheric circulation is studied by examining the distribution of discomfort cases across six objectively defined circulation types over Europe, based on Athens weather characteristics. High values of the PMV discomfort index are mainly associated with two typical high-summer pressure patterns with the intensity of discomfort depending on the pressure gradient over the Aegean Sea. On the contrary, low PMV discomfort index values prevail mainly on days typified by the other four circulation types, which are more frequent during May, June, and September.

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Section: Resultssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Climatic characteristics of summer human thermal discomfort in Athens and its connection to atmospheric circulation

Bartzokas

Lolis

Kassomenos

et al. 2013

Nat. Hazards Earth Syst. Sci.

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“…For maximum temperatures, the results did not differ significantly from zero. Furthermore, an urban effect on the maxima was neither theoretically well explained nor clearly confirmed in the above works, although Philandras et al (1999) reported an urban effect in Athens that was stronger in the maximum than in the minimum temperatures. Hence, in the present study, this empirical urban correction is applied to the local representative series of each region, as a function of its population, but only for the minimum temperatures The urban thermal effect is generally weaker in Europe than in northern America and the corresponding adjustment factor of 0.7 (Karl et al, 1988) is applied and discussed for Spain.…”

Section: The Empirical Urban Adjustmentmentioning

confidence: 79%

Homogenization of long‐term monthly Spanish temperature data

Staudt

Esteban‐Parra

Castro‐Díez

2007

Intl Journal of Climatology

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Abstract:Reliable time-series is the basic ingredient when analysing climatic changes. However, the errors in real data are frequently of the same order as the signal being sought. Therefore, the available long-term monthly series of Spanish minimum and maximum temperatures have been compiled from the late 19th century on, in order to compile a high-quality data set. The series are organized into climatically homogeneous regional groups and, in each group, the detection and adjustment is based on relative homogeneity and an analysis of the stationarity of the whole set of temperature-difference series. These series are scanned with moving t, Alexandersson, and Mann-Kendall tests. The detected inhomogeneities are adjusted by weighted averages of the regional series. The method is iterative and advances in steps of detection, adjustment, and actualization. Individual inhomogeneous data are discarded and gaps are filled by similar weighted multiple means.For the analysis of the temperature evolution in the Iberian Peninsula, each region is finally represented by one local series and the regional average. The urban effect on minimum temperatures is adjusted by an empirical method, and for Madrid also by a correction derived from new homogenized data. Generally, rigorous homogeneity cannot be achieved because the initial data quality is deficient in many cases and metadata are sparse. Nevertheless, the data homogeneity and quality has been considerably enhanced: the total error margin in a series is of the order of 0.3°C-0.4°C, under consideration of a worst-case error accumulation. On the other hand, the number of inhomogeneities is considerable and their average amplitude is of the order of 1°C reflecting the much larger error margin in the raw data. The homogenized dataset compiled constitutes an important basis for the subsequent detection of thermal changes in Spain in the last 130 years, on a clearly higher confidence level than before.

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“…So far, it has been found that the effect of UHI is best marked in the summer and warmer part of the year (Oke 1982;Kłysik and Fortuniak 1999;Philandras et al 1999;Morris et al 2001), while in a daily cycle, the highest intensity of UHI occurs at night (Ripley et al 1996;Jauregui 1997;Magee et al 1999;Montavez et al 2000;Tereshchenko and Filonov 2001;Dousset and Gourmelon 2003). The intensity of UHI decreases as cloudiness and wind speed increase (Oke 1982;Voogt 2004) and is greatest during anticyclonic conditions (Oke 1988;Morris and Simmonds 2000;Arnfield 2003).…”

Section: Introductionmentioning

confidence: 99%

The urban heat island in the city of Poznań as derived from Landsat 5 TM

Majkowska

Kolendowicz

Półrolniczak

et al. 2016

Theor Appl Climatol

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To study urban heat island (UHI), Landsat 5 TM data and in situ measurements of air temperature from nine points in Poznań (Poland) for the period June 2008-May 2013 were used. Based on data from measurement points located in different types of land use, the surface urban heat island (SUHI) maps were created. All available and qualitycontrolled Landsat 5 TM images from 15 unique days were used to obtain the characteristics of land surface temperature (LST) and UHI intensity. In addition, spatial analysis of UHI was conducted on the basis of Corine Land Cover 2006 dataset. In situ measurements at a height of 2 m above ground level show that the UHI is a common occurrence in Poznań with a mean annual intensity of 1.0°C. The UHI intensity is greater during the warm half of the year. Moreover, results based on the remote sensing data and the Corine Land Cover 2006 indicate that the highest value of the mean LST anomalies (3.4°C) is attained by the continuous urban fabric, while the lowest value occurs within the broad-leaved forests (−3.1°C). To re-count from LST to the air temperature at a height of 2 m above ground level (T agl ), linear and non-linear regression models were created. For both models, coefficients of determination equal about 0.80, with slightly higher value for the non-linear approach, which was applied to estimate the T agl spatial variability over the city of Poznań.

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Climate Variability and Urbanization in Athens

Cited by 86 publications

References 9 publications

Climatic characteristics of summer human thermal discomfort in Athens and its connection to atmospheric circulation

Climatic characteristics of summer human thermal discomfort in Athens and its connection to atmospheric circulation

Homogenization of long‐term monthly Spanish temperature data

The urban heat island in the city of Poznań as derived from Landsat 5 TM

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