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

2013 ◽  
Vol 13 (12) ◽  
pp. 3271-3279 ◽  
Author(s):  
A. Bartzokas ◽  
C. J. Lolis ◽  
P. A. Kassomenos ◽  
G. R. McGregor
Keyword(s):  
Pressure Gradient ◽  
Atmospheric Circulation ◽  
Aegean Sea ◽  
The Other ◽  
Thermal Discomfort ◽  
Circulation Types ◽  
Light Wind ◽  
Discomfort Index ◽  
Climatic Characteristics ◽  
Weather Characteristics

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.

Trends of Outdoor Thermal Discomfort in Mymensingh: an Application of Thoms’ Discomfort index

2018 ◽  
Vol 10 (2) ◽  
pp. 151-156 ◽  
Author(s):  
MSJ Talukdar ◽  
MS Hossen ◽  
MA Baten
Keyword(s):  
Risk Assessment ◽  
Natural Resources ◽  
Thermal Comfort ◽  
Air Temperature ◽  
The Other ◽  
Thermal Discomfort ◽  
Other Hand ◽  
Discomfort Index

Thermal comfort is considered very important in aspects of risk assessment, summertime morbidity or in building designing. The present study applied Thom’s discomfort index (DI) to assess the trend of outdoor thermal discomfort in Mymensingh City during 2006-2015. It wasfound that December to February months was comparatively comfortable, DI values were typically <21 and therefore no people felt any discomfort in these months. On the other hand, under 50% population experienced discomfort during March and November months when discomfort valueswere ranged between 21- 24. From April to October months discomfort values varied from 25-27, which indicated thatover 50% population suffered from discomfort in this period. Though no extreme discomfort condition observed in Mymensingh city, the results revealed from June to September months most of the population suffered from severe discomfort in Mymensingh city due to the high air temperature, and high relative humidity.J. Environ. Sci. & Natural Resources, 10(2): 151-156 2017

scholarly journals Relationships of surface air temperature anomalies over Europe to persistence of atmospheric circulation patterns conducive to heat waves

2008 ◽  
Vol 14 ◽  
pp. 243-249 ◽  
Author(s):  
J. Kyselý ◽  
R. Huth
Keyword(s):  
Atmospheric Circulation ◽  
Air Temperature ◽  
Heat Waves ◽  
Temperature Extremes ◽  
Human Society ◽  
Positive Temperature ◽  
Temperature Anomalies ◽  
Circulation Types ◽  
Circulation Patterns ◽  
Air Temperature Anomalies

Abstract. Heat waves are among natural hazards with the most severe consequences for human society, including pronounced mortality impacts in mid-latitudes. Recent studies have hypothesized that the enhanced persistence of atmospheric circulation may affect surface climatic extremes, mainly the frequency and severity of heat waves. In this paper we examine relationships between the persistence of the Hess-Brezowsky circulation types conducive to summer heat waves and air temperature anomalies at stations over most of the European continent. We also evaluate differences between temperature anomalies during late and early stages of warm circulation types in all seasons. Results show that more persistent circulation patterns tend to enhance the severity of heat waves and support more pronounced temperature anomalies. Recent sharply rising trends in positive temperature extremes over Europe may be related to the greater persistence of the circulation types, and if similar changes towards enhanced persistence affect other mid-latitudinal regions, analogous consequences and implications for temperature extremes may be expected.

scholarly journals Zonal Momentum Balance in the Tropical Atmospheric Circulation during the Global Monsoon Mature Months

2013 ◽  
Vol 70 (2) ◽  
pp. 583-599 ◽  
Author(s):  
Wenchang Yang ◽  
Richard Seager ◽  
Mark A. Cane
Keyword(s):  
Angular Momentum ◽  
Pressure Gradient ◽  
Atmospheric Circulation ◽  
Coriolis Force ◽  
Gradient Force ◽  
Pressure Gradient Force ◽  
Global Monsoon ◽  
Upper Troposphere ◽  
Nonlinear Advection ◽  
Zonal Momentum

Abstract In this paper, zonal momentum balances of the tropical atmospheric circulation during the global monsoon mature months (January and July) are analyzed in three dimensions based on the ECMWF Interim Re-Analysis (ERA-Interim). It is found that the dominant terms in the balance of the atmospheric boundary layer (ABL) in both months are the pressure gradient force, the Coriolis force, and friction. The nonlinear advection term plays a significant role only in the Asian summer monsoon regions within the ABL. In the upper troposphere, the pressure gradient force, the Coriolis force, and the nonlinear advection are the dominant terms. The transient eddy force and the residual force (which can be explained as convective momentum transfer over open oceans) are secondary, yet cannot be neglected near the equator. Zonal-mean equatorial upper-troposphere easterlies are maintained by the absolute angular momentum advection associated with the cross-equatorial Hadley circulation. Equatorial upper-troposphere easterlies over the Asian monsoon regions are also controlled by the absolute angular momentum advection but are mainly maintained by the pressure gradient force in January. The equivalent linear Rayleigh friction, which is widely applied in simple tropical models, is calculated and the corresponding spatial distribution of the local coefficient and damping time scale are estimated from the linear regression. It is found that the linear momentum model is in general capable of crudely describing the tropical atmospheric circulation dynamics, yet the caveat should be kept in mind that the friction coefficient is not uniformly distributed and is even negative in some regions.

Pressure and Flow—Chickens and Eggs

2011 ◽  
pp. 63-69
Author(s):  
James R. Munis
Keyword(s):  
Pressure Gradient ◽  
Flow Rate ◽  
The Other ◽  
Pressure Gradients ◽  
Variable Effect ◽  
Paddle Wheel ◽  
Independent Variable ◽  
Mechanical Pump

We tend to assume that when 2 things are associated with each other, one must be causing the other. Nothing could be further from the truth, though. Because we're used to seeing the independent variable (‘cause’) plotted on the x-axis and the dependent variable (‘effect’) on the y-axis, this equation and graph suggest that the pressure gradient causes the paddle wheel flow rate. That, of course, is nonsense. This type of specious thinking is intended to warn you away from assuming that relationships necessarily imply causality. As you've learned already, pressure is not the same thing as energy, and pressure by itself cannot perform work or generate flow. However, flow generated by pressure-volume work (either by the heart or a mechanical pump) certainly can create pressure gradients. In this sort of chicken (flow) or egg (pressure) question, if the only energy-containing term is flow, then I'll say that the chicken came first.

First records of six species of crustaceans for the eastern Mediterranean Sea

Crustaceana ◽  
2019 ◽  
Vol 92 (11-12) ◽  
pp. 1403-1414
Author(s):  
Ozge Ozgen ◽  
Sermin Acik ◽  
Kerem Bakir
Keyword(s):  
Mediterranean Sea ◽  
New Record ◽  
New Records ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Posidonia Oceanica ◽  
The Other ◽  
Eastern Mediterranean Sea ◽  
Crustacean Species ◽  
Ecological Characteristics

Abstract This paper deals with six crustacean species associated with Posidonia oceanica (Linnaeus) Delile, 1813 meadows along the Aegean coasts of Turkey: Caprella tavolarensis, Eriopisella ruffoi, Iphimedia vicina, Astacilla mediterranea, Apseudopsis minimus and Macropodia deflexa. Apseudopsis minimus is a new record for the Turkish coast of the Aegean Sea, the other five species are new records for the eastern Mediterranean. Brief descriptions of the species and their morphological and ecological characteristics are given.

scholarly journals Relationship between Water Temperature of Polish Rivers and Large-Scale Atmospheric Circulation

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1690 ◽  
Author(s):  
Renata Graf ◽  
Dariusz Wrzesiński
Keyword(s):  
Water Temperature ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Statistical Significance ◽  
Winter Season ◽  
Circulation Type ◽  
River Waters ◽  
Positive And Negative Coefficients ◽  
Circulation Types ◽  
Temporal And Spatial Variability

The objective of the paper consisted in determining the effect of macroscale types of NAO, AO, EA, EAWR, SCAND, and AMO atmospheric circulation on changes in water temperature in Polish rivers. The study has made use of a broad body of hydrometeorological materials covering daily water temperature values for 96 water gauge stations located on 53 rivers and air temperature values for 43 meteorological stations. Percentage shares of positive and negative coefficients of correlation of annual, seasonal, and monthly circulation type indices with air and river water temperature were determined, demonstrating the character of teleconnection. Determinations were made of water temperature deviations in positive and negative phases of the analyzed indices from average values from the years 1971–2015, and their statistical significance ascertained. Research has shown that relations between the temperature of river waters in Poland and macroscale circulation types are not strong, however they are noticeable, sometimes even statistically significant, and both temporally and spatially diverse. NAO, AO, EA, and AMO indices are characterized by a generally positive correlation with temperature, whereas SCAND and EWAR indices are characterized by a negative correlation. Research showed a varying impact of types of atmospheric circulation, with their effectiveness increasing in the winter season. The strongest impact on temperature was observed for the positive and negative NAO and AO phases, when deviations of water temperature from average values are correspondingly higher (up to 1.0 °C) and lower (by a maximum of 1.5 °C), and also for the positive and negative SCAND phases, when water temperature are correspondingly lower (by a maximum of 0.8 °C) and higher (by 1.2 °C) than average values. The strongest impact on water temperature in summer, mainly in July, was observed for AMO. The results point to the complexity of processes determining the thermal regime of rivers and to the possibility of additional factors—both regional and local—exerting an influence on their temporal and spatial variability.

Spatio-temporal changes of drought in Romania (1961-2015), according to atmospheric circulation types and teleconnection indices

2020 ◽  
Author(s):  
Radu-Vlad Dobri ◽  
Liviu Apostol ◽  
Lucian Sfîcă ◽  
Simona Țîmpu ◽  
Ion-Andrei Niță
Keyword(s):  
Atmospheric Circulation ◽  
Standardized Precipitation Index ◽  
Atmospheric Precipitation ◽  
Climatic Conditions ◽  
Extreme Drought ◽  
Drought Severity ◽  
Severe Drought ◽  
Circulation Types ◽  
Teleconnection Indices ◽  
Moderate Drought

&lt;p&gt;Drought can be determined by climatic conditions (atmospheric precipitation, water supply from soil accessible to the plant, moisture and air temperature and wind speed) but is also induced by environmental aspects some of them related to anthropogenic influences.&lt;/p&gt;&lt;p&gt;In order to monitor the drought and its impact for Romania, four indices were analyzed in the present study (SPI (Standardized Precipitation Index), PNI (Percent of Normal Index), DI (Deciles index), and ZSI (Z-score Index)), through Meteorological Drought Monitoring software, using the total daily amount of precipitation for 27 weather stations in Romania, of which 22 stations for the period 1961-2015, 4 stations for the period 1961-2000 and one station for the period 1964-2015.&lt;/p&gt;&lt;p&gt;Preliminary analyzes resulting from the use of these indices were correlated with 18 GWT (Gro&amp;#223;wettertypen) atmospheric circulation types of daily mean sea level pressure (SLP). This was done using COST733 class software to evaluate the influence of large-scale mechanisms of atmospheric circulation. Also, four teleconnection indices were used, more exactly AO (Arctic Oscillation), NAO (North Atlantic Oscillation), PNA (Pacific-North American Pattern) and AAO (Antarctic Oscillation) that are recognized for their effect on climatic conditions at European scale, &amp;#160;&lt;br&gt;provided by National Oceanic and Atmospheric Administration (NOAA) &amp;#8211; Climate Prediction Center.&lt;/p&gt;&lt;p&gt;Therefore, according to the types of circulation, the amount of precipitation produced in certain areas and implicitly the degree of drought severity is influenced. The types of anticyclonal circulation 13, 16 or 18, for example, which occur on average in 46 (12.7%), 14 (3.9%) , respectively 20 (5.4%) days a year, cause less precipitation as known, compared to the types of cyclonal circulation 1, 2 or 17 for example with an average of 12 (3.2%), 12 (3.2%), respectively 19 (4.3%) days a year.&lt;/p&gt;&lt;p&gt;In terms of drought analysis indices, according to SPI, the entire analysis interval for Iasi, located in the northeast region of Romania, was 6 years of &quot;moderately dry&quot;, 5 years of &quot;severely dry&quot;, and one year of &quot;extremely dry&quot;, unlike Cluj, located in the central western region, with two years of &quot;moderately dry&quot;, 3 years of &quot;severely dry&quot; and two years of &quot;extremely dry&quot;. In Bucharest, located in the southern region of Romania there were 4 &quot;moderately dry&quot; years and 5 &quot;severely dry&quot; years. In Iasi, according to the ZSI index with the same classifications as the SPI index, there were 3 &quot;moderately drought&quot; years, 7 &quot;severely drought&quot; years and 7 &quot;extreme drought&quot; years, while in Cluj there were 9, 3 and respectively 6 years and in Bucharest 7, 5 and respectively 6 years with the above classification.&lt;/p&gt;&lt;p&gt;According to the PNI index, there were 5 &quot;moderate drought&quot; years in Iasi and Cluj and 6 &quot;moderate drought&quot; years in Bucharest. Also, there were 9 &quot;weak drought&quot; years in Iasi, 3 in Cluj and 5 in Bucharest.&lt;/p&gt;&lt;p&gt;And last but not least, according to the DI index, at all 3 stations there were 5 &quot;extreme drought&quot; years, 6 &quot;severe drought&quot; years and 5 &quot;moderate drought&quot; years.&lt;/p&gt;

scholarly journals Assessing extreme droughts in Spain during 1750–1850 from rogation ceremonies

2012 ◽  
Vol 8 (2) ◽  
pp. 705-722 ◽  
Author(s):  
F. Domínguez-Castro ◽  
P. Ribera ◽  
R. García-Herrera ◽  
J. M. Vaquero ◽  
M. Barriendos ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
The Other ◽  
Other Hand ◽  
Meteorological Hazards ◽  
Instrumental Period ◽  
Climatic Characteristics ◽  
Instrumental Series ◽  
Rainfall Deficits

Abstract. Among the different meteorological hazards, droughts are those with the highest socio-economical impact on the Iberian Peninsula. Drought events have been largely studied in the instrumental period, but very little is known about the characteristics of droughts in the preinstrumental period. In this work, several series of rogation ceremonies are used to identify severe droughts within the period 1750–1850. The overlapping of the rogation series with some instrumental series served to identify some climatic characteristics of rogation ceremonies: (a) during spring, rainfall deficits needed to celebrate rogation ceremonies are smaller than in any other season; (b) the hydrological deficit in a particular region increases with the number of locations celebrating rogations simultaneously. On the other hand, it was found that between 1750–1754 and 1779–1783 are probably the driest periods of the 101 analyzed years. Both show an important number of rogations all over Iberia and during all the seasons. The most extended drought of this period occurred during the spring of 1817, affecting 15 of the 16 locations studied. This drought was influenced by the Tambora eruption (1815). The study of the climate footprint of this eruption and its comparison with similar situations in the series suggest that the spring drought of 1824 may be associated with the eruptions of the Galunggung and Usu volcanoes (1822). Further studies are required to confirm this fact and understand the atmospheric mechanisms involved.

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