Sultry

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Climatological knowledge

Day temperature T: max / med / min
Day temperature  T : max / med / min

Air temperature dependent days
  • T max  ≥ 35 ° C
    		•  Desert day
  • T max  ≥ 30 ° C
    		•  Hot day
  • T min ≥ 20 ° C
    		•  Tropical night
  • T max ≥ 25 ° C
    		•  Summer day
  • T med <15 ° C / 12 ° C
    		•  Heating day
  • T med ≥ 5 ° C
    		•  Vegetation day
  • T min <0 ° C
    		•  Frost day
  • T max <0 ° C
    		•  Ice day
    not uniformly defined: Cold day
    Weather- dependent days
    Cloud cover Bright day
    Cloud cover Cloudy day
    Cloud cover Foggy day
    Humidity / temperature Sultry day
    Precipitation Precipitation day
    Precipitation Rainy day
    Precipitation Hail day
    Precipitation Snow (cover) day
    storm Storm day
    storm Thunderstorm day

    As humidity or heat and humidity refers to the fact a thick with water vapor saturated ambient air at high air temperatures . Accordingly, this has a high relative humidity and therefore hinders the thermoregulation of the human body through perspiration (sweating). As a result, humid heat is perceived as significantly more uncomfortable or even warmer than dry heat, i.e. ambient air with low relative humidity. This relationship is quantitatively described by the heat index .

    Basics

    Whether the weather is perceived as humid depends on the amount of water in the air, also known as absolute humidity  (AF).

    A dew point of 16 ° C is assumed as a limit value from which sultriness begins, which under normal conditions corresponds to an absolute humidity of 13.5 g water vapor per cubic meter of air. Other sources set the humidity limit at the dew point 17 ° C, corresponding to a vapor pressure of 18.8 hPa.

    Temperature and relative humidity at which an absolute humidity of 13.5 g / m 3 is achieved
    temperature rel. Humidity temperature rel. Humidity
    16 ° C 99% 27 ° C 53%
    17 ° C 93% 28 ° C 50%
    18 ° C 88% 29 ° C 47%
    19 ° C 83% 30 ° C 45%
    20 ° C 78% 31 ° C 43%
    21 ° C 74% 32 ° C 40%
    22 ° C 70% 33 ° C 38%
    23 ° C 66% 34 ° C 36%
    24 ° C 62% 35 ° C 35%
    25 ° C 59% 36 ° C 33%
    26 ° C 56% 37 ° C 31%

    Since the air cools down to approximately the current dew point at night - without a change in air mass - and the dew point rises somewhat during the day, a morning low temperature of more than 15 ° C means that a muggy day can be expected. If the lowest temperature on a so-called tropical night is over 20 ° C, the humid atmosphere becomes difficult to bear for many Central Europeans.

    A usual indication of a humid day is now made via the vapor pressure of the air, with vapor pressure> 18  hPa . An early definition goes back to Scharlau (1943) and was 14.08  mm mercury column for the vapor pressure.

    Other temperature measures also take into account other factors such as global radiation (total radiation), wind speed , and stratification of the atmosphere ( general weather situation ). An estimate can be made using the Physiologically Equivalent Temperature  (PET) as a measure for heat stress, here a heavy load typically occurs at PETd> 35. Another measured value is the equivalent temperature (TEQ, T EQ ) according to Auer (2001), with muggy at TEQ> 65 ° C.

    If the thermoregulation is severely impaired, the risk of circulatory collapse and other heat damage increases . Particularly tropical and partly subtropical climates are characterized by humid weather conditions, which, however, usually only leads to health consequences in the case of an unsuitable organism or unsuitable behavior. No major physical exertion should therefore be undertaken without adequate acclimatization to these conditions. But even in the moderate climate of the middle latitudes and particularly close to large metropolitan areas, summer weather can be so humid that one is often unprepared for it in Central Europe - for example, as in August 2003 or July 2006.

    Regional

    Karlsruhe and Mannheim / Ludwigshafen am Rhein are among the most humid places in Germany , as these cities are located on the Rhine plain . Due to the Rhine and the topography, this always has a very high humidity. In addition, there are the high temperatures (warmest region in Germany), which can often lead to tropical nights in summer.

    The most humid areas in Austria are the Neusiedlersee and Seewinkel and the Danube to Vienna , with an average of 25 to 30 humid days per year (PETd or TEQ determination): Here the combination of the steppe lake or river with the hot summer Pannonian climate is noticeable. The inner cities of Vienna and Graz achieve similar values. In large parts of the valleys of the Alpine region, the average is around ten to 15 days, and at high altitudes it is five to ten days.

    literature

    • W. Dammann: Humidity as a climate factor. In: Ber. German Landeskunde 32 (l), 1964, pp. 100-114.
    • Herwig Wakonigg: The sultriness in Styria . With extensive meteorological definitions. In: Communications of the natural science association for Styria . tape 105 , 1975, pp. 115–125 ( PDF file; 1.5 MB [accessed October 22, 2013]).
    • K. Scharlau: The sultriness as a measurable quantity. In: Bioklimat. Supplement. 10, 1943, pp. 19-23.

    Web links

    Wiktionary: Sultry  - explanations of meanings, word origins, synonyms, translations

    Individual evidence

    1. ↑ Note: In contrast to the color markings for the temperature thresholds, the 0 ° C line on the graphic is on the border between turquoise and blue. →  Annual cycle of the graphic (animated)
    2. ↑ a b c d e f g h i j k l m n o Climatological knowledge days in the weather dictionary of the German Weather Service
    3. ↑ Germany : 15 ° C according to VDI 2067 ; Austria , Switzerland , Liechtenstein : 12 ° C according to Usance
    4. ↑ also T med ≥ 10 ° C: day of the main vegetation period
    5. ^ DWD Weather Lexicon: Sultry
    6. ↑ Andreas Matzarakis, Christina Endler, Elisabeth Koch, Robert Neumcke, Ernest Rudel; Central Institute for Meteorology and Geodynamics (ZAMG), Meteorological Institute of the University of Freiburg (MIF): Effects of climate change on climatic tourism potential . StartClim2006.D2, Vienna July 2007, p. 12 ( pdf , austroclim.at)
    7. ↑ a b Herwig Wakonigg: The sultriness in Styria . With extensive meteorological definitions. In: Communications of the natural science association for Styria . tape 105 , 1975, pp. 116 ( PDF file; 1.5 MB [accessed October 22, 2013]).
    8. ↑ ZAMG, MIF: Effects of Climate Change 2007, Section D2-2 State of the art , p. 7 ff
    9. ^ I. Auer; Office of the Vorarlberg state government (ed.): Climate of Vorarlberg . Volume 1, 2001, p. OA
    10. ^ A b Franz Prettenthaler, Alexander Podesser; Harald Pilger (Hrsg.): Climate atlas Styria. Period 1971-2000. A user-oriented climatography. Series of studies on climate change in Austria 4, Austrian Academy of Sciences, ISBN 978-3-7001-6754-9 ; updated: A. Podesser, F. Wölfelmaier Version, ZAMG (Hrsg.), Version 2.0 ( Weblink , Umwelt.steiermark.at), Chapter 3 Humidity, Clouds and Fog , p. 60 ff ( pdf , ibid.).
    11. ↑ ZAMG, MIF: Effects of Climate Change 2007, Tab. D2-15: Trend of days with heat stress (PET> 35 ° C) for the selected stations in Austria , p. 41