Who has not dreamed of. cloudless sky, fresh snow covered mountains, clear air and a stable high pressure area, the planning of leisure activities Days also gives you wings. But like most things in life, this weather has a downside.
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| surface chart dated 01/31/2011: High Christl (! Only the third party) is spreading - deep-John (already the 10th of the season) runs north past | |
anticyclones pumps are usually huge body of air, sucking the air in a few 1000 km altitude and below. This large-scale decrease in poverty ensures clouds, day and night. While the end-January-sun during the day has a lot of energy (diurnal variations of 18-19 degrees possible), radiant appears to have the clear nights, a very different outcome.
The Earth's surface radiates at night and it forms a inversion from (next image). Especially on the valley floor to the cold air, which also flows from the snow-covered slopes. In the lowlands, however, the surface is small compared to the volume, therefore cooling is not as strong. If the meadows and snow-covered slopes, these Auskühlungseffekt is further strengthened.
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| Scheme of inversion weather conditions: cold air under warmer air act negatively on vertical exchange of air masses. With the daily solar radiation (right), on the southern slope updrafts form. |
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| particulate pollution at 31.01. be reduced |
The air quality measurement of the Tyrol, for example, delivers on its website a variety of measurements and measurements of all major pollutants: http://www.tirol.gv.at/themen/umwelt/luft/.
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| particulate pollution at 01.02. - Compared to the previous day more stations "loaded" |
The ALPNAP project in winter 2005/06 with a variety of measurements has a valuable contribution to the understanding of micrometeorological processes. Based on these studies are based predictive models and rules for the Intiierung the IG-L, Immissionsgesetz air, making for a Verringerrung the speed limit (not just in the Inn Valley). At a lower speed will not only generates less pollution, there are also micro-particles such as dust, rubber dust, Dust from grit ... not so much stirred up. The deposition is thus greater, the substances are not even in the air.
Exposure to PM10 is shown in Figures 3, 4 and 5. Due to the lack of exchange with the lower layers of air above it finds a possible dilution of the particulate matter does not occur. Light winds for days not affect positively on the improvement of fine particulate pollution, but has continual Taleinwind from 31.01. to 01.02. the burden in the Inn Valley strengthened (Figures 5 and 6 compare to the last two days).
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| course of the concentrations of NO2, NO and PM 10 selected stations in Tyrol (Source: http://imgi.uibk.ac.at/alpnap/index.html). |
end to this situation indicates stable weather up to a slowdown on Friday, will not start. A trip through the inversion layer (800 - 1000 m) or inweniger contaminated regions (Upper Inn Valley) has a healthy effect on cases.
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| wind end of January in Innsbruck | | | | |
References:
surface weather map (1): wetterpate.de
scheme of the layer of air movement during a high-pressure inversion conditions (2): alpen.wetter
PM10 pollution in Tirol (3 + 4) for the 31.01. and 02.01.2011: tirol.gv.at / air
profiles of air pollutants at the monitoring stations (5): http://imgi.uibk.ac.at/alpnap/index.html wind direction and wind speed
at the Uni-Innsbruck (6): imgi.uibk.ac.at
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