First, what is the apparent temperature (felt temperature)?
Before discussing the influence of wind speed on the felt temperature it would be useful to have a better understanding of what we are talking about, right? So let's start with an update on the weather. When we talk about air temperature or temperature under shelter, we are talking about the temperature measured with a thermometer or a probe placed 1.5 metres above the ground, inside an open-air shelter, well protected from the wind and the weather.
But the reality is often different, precisely because of the winds and the weather. On the one hand, the physiological perception of temperature varies from person to person, but on the other hand, it varies according to atmospheric conditions.
As you know, a dry, calm, and sunny 20 degrees does not feel at all the same as 20 degrees with strong wind and rain. The weather is important, especially in the United Kingdom where the climate is varied (but less so than in the northernmost regions of the world). With a strong northerly wind, the felt temperature changes dramatically!
The feeling of cold is therefore reinforced when the wind joins the party, even with the same temperature. The higher the wind speed, the greater the cooling.
Does wind speed affect the felt temperature?
So we've just answered that big question: yes, the felt temperature changes according to the wind's speed. Let's go into a little more detail about this weather phenomenon that occurs in the United Kingdom and around the world.
Besides, it doesn't matter which way the wind blows, it's the speed that counts.
The wind speed, therefore, changes the actual temperature, which is called the felt temperature. But this is a common term, the real name of this phenomenon is wind chill.
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What is wind chill?
More importantly, does wind chill have anything to do with wind turbines? Apart from the association with wind, not really…
The wind chill is the correct term, better known in popular parlance as the felt temperature. It is simply the sensation of cold that the wind causes on a living organism that radiates heat (like your body), while there is no change in the actual air temperature.
The principle is physical and rather simple, but not obvious: when there is no wind, a thin layer of warm air moistened by the body forms on the surface of the skin. But this small insulating protection is perpetually blown away when it's windy!
Without this layer, our skin is then directly in contact with colder and drier air.* The consequences? The skin gradually dries out as it warms the air to restore this balance… which immediately cools our body (this requires a lot of energy). So that's why, is the principle now clear to you? It's no coincidence that you feel cold when the wind starts to blow.
By now you know that wind chill has nothing to do with a wind turbine, but is the name given to the effect of the wind on the felt temperature. Is the direction of the wind as important as the wind speed?
And does the direction of the wind have an impact on the temperature in the United Kingdom?
It is common to hear that the north wind brings cold weather to the United Kingdom and other neighbouring countries. But is it true that winds coming from this direction cause the temperature, or at least the felt temperature, to drop?
As we have seen above, regardless of the direction of the wind, the wind (unless it is hot) lowers the apparent temperature compared to the "official" temperature. North winds, which are generally colder than other winds, have the effect of making this wind chill even colder. In the United Kingdom, this occurs often. But in Canada, for example, it's much worse because the temperature is lower in winter and the wind can blow very fast!
But the wind from another direction, from the east, west, or south, will also have a cooling effect. The only exception is when the wind temperature is higher than the air temperature.
How is wind chill measured?
Measuring the apparent temperature is not straightforward but it is possible to calculate wind chill. To do this, meteorologists have developed a wind chill index using an empirical mathematical relationship illustrated in the form of a table known to any good meteorologist.
This table takes into account two main variables, air temperature, and wind speed, precisely to evaluate the effects of the latter on the former.
This measure is mostly used in regions with a very harsh climate, such as Canada and in very northern locations, but it can also be applied in some places in the United Kingdom. It is important to know that the lower the temperature, the more the wind reinforces the feeling of cold.
The impact that wind has on temperature is measured with the wind index (again, nothing to do with a wind turbine), which is a number without units. Let's use an example: if the temperature is 0°C and the wind blows at 40 km/h, the wind chill index will be -6°C. In concrete terms, this means that the apparent temperature will be -6°C without wind.
You may have guessed it, but now you understand the principle: wind speed (no matter its direction) has a strong influence on the felt temperature of the human body. The stronger the wind, the colder it feels. So take into account how windy it is when thinking about what you should wear! And why not start measuring the weather data to make sure you don't make a mistake?
Kwanza, ni nini joto la wazi (joto waliona)? Kabla ya kujadili ushawishi wa upepo kasi juu ya kuhisi joto itakuwa na manufaa ya kuwa na uelewa bora wa nini sisi ni kuzungumza juu ya, haki? Kwa hiyo, hebu tuanze na taarifa mpya kuhusu hali ya hewa. Wakati tunazungumza juu ya joto la hewa au joto chini ya makazi, tunazungumza juu ya joto lililopimwa na thermometer au probe iliyowekwa mita 1.5 juu ya ardhi, ndani ya makazi ya wazi, salama na salama kutoka kwa upepo na hali ya hewa. Lakini mara nyingi hali huwa tofauti, hasa kwa sababu ya upepo na hali ya hewa. Kwa upande mmoja, hisia ya kisaikolojia ya joto hutofautiana kutoka mtu mmoja hadi mwingine, lakini kwa upande mwingine, inatofautiana kulingana na hali ya anga. Kama unavyojua, joto la joto la joto, la joto la joto, na la joto la joto la joto halijulikani kuwa sawa na joto la joto la joto la joto la joto la joto la joto la joto la joto la joto la joto. Hali ya hewa ni muhimu, hasa katika Uingereza ambapo hali ya hewa ni tofauti (lakini si hivyo kuliko katika mikoa ya kaskazini ya dunia). Ukiwa na upepo mkali wa kaskazini, halijoto ya hewa hubadilika sana! Kwa hiyo, hisia ya baridi huimarishwa wakati upepo unapoungana na kikundi hicho, hata ikiwa na halijoto ileile. Kadiri upepo unavyoenda kwa kasi zaidi, ndivyo baridi inavyoongezeka. Je, mwendo wa upepo huathiri halijoto ya mviringo? Kwa hiyo, swali la kwanza ni kwamba, je, joto la hewa hubadilika kulingana na upepo? Hebu tuangalie kwa undani zaidi hali hii ya hewa ambayo hutokea nchini Uingereza na ulimwenguni kote. Isitoshe, haijalishi upepo unavuma upande gani, ni mwendo unaohesabiwa. Kwa hiyo, mwendo wa upepo hubadili halijoto halisi, inayoitwa halijoto ya hisia. "Jina la kawaida la tukio hili ni ""Wind Chill.""" Je, ungependa kupima kwa usahihi zaidi joto la nje na la ndani? Na Netatmo Smart Weather Station kupokea kipimo sahihi ya data hii yote (na zaidi) moja kwa moja kwenye smartphone yako. Kituo cha hali ya hewa cha Netatmo Smart Weather Station ni kituo cha hali ya hewa cha hali ya hewa na kina uwezo wa kuwasiliana na hali ya hewa na hali ya hewa. Upepo baridi ni nini? Jambo la muhimu zaidi ni kwamba, je, baridi ya upepo inahusiana na turbini za upepo? "Kutokana na hali ya hewa, ""wind chill"" ni neno linalofaa zaidi, linalojulikana kama ""feel temperature.""" Ni hisia ya baridi ambayo upepo husababisha kwenye kiumbe hai ambacho kinatoa joto (kama mwili wako), wakati hakuna mabadiliko katika joto halisi la hewa. Kanuni ni ya kimwili na ni rahisi, lakini si dhahiri: wakati hakuna upepo, tabaka nyembamba ya hewa ya joto humidified na mwili huunda juu ya uso wa ngozi. Lakini ulinzi huo mdogo wa kutenganisha hewa huvunjwa-vunjwa daima wakati wa upepo! Bila tabaka hilo, ngozi yetu huwa inagusa hewa baridi na kavu zaidi. * Matokeo yake? Ngozi huoka hatua kwa hatua wakati inapopiga hewa ili kurudisha usawa huu... ambayo mara moja hupunguza mwili wetu (hii inahitaji nishati nyingi). Kwa hiyo, je, sasa unaelewa kanuni hiyo? Si bahati mbaya kwamba unahisi baridi wakati upepo unapoanza kuvuma. Kwa sasa unajua kwamba baridi ya upepo haina uhusiano wowote na turbine ya upepo, lakini ni jina linalopewa athari ya upepo kwenye joto la hisia. Je, mwelekeo wa upepo ni muhimu kama mwendo wa upepo? Je, upepo una athari kwa joto la dunia? Ni kawaida kusikia kwamba upepo wa kaskazini huleta hali ya hewa baridi kwa Uingereza na nchi nyingine jirani. Lakini je, ni kweli kwamba upepo unaotoka upande huo husababisha halijoto, au angalau halijoto inayohisiwa, ipungue? Kama tulivyoona hapo juu, bila kujali mwelekeo wa upepo, upepo (isipokuwa ni moto) hupunguza joto la wazi ikilinganishwa na joto la "rasmi". Upepo wa kaskazini, ambao kwa ujumla ni baridi kuliko upepo mwingine, una athari ya kufanya upepo huu u baridi hata baridi zaidi. Katika Uingereza, jambo hilo hutukia mara nyingi. Lakini katika Kanada, kwa mfano, ni mbaya zaidi kwa sababu joto ni chini katika majira ya baridi na upepo unaweza kuvuma haraka sana! Lakini upepo kutoka upande mwingine, kutoka mashariki, magharibi, au kusini, utakuwa na athari ya baridi pia. Tofauti pekee ni wakati joto la upepo ni juu kuliko joto la hewa. Baridi ya upepo hupimwaje? Kupima joto dhahiri si rahisi lakini inawezekana kuhesabu baridi ya upepo. Kwa kufanya hivyo, wataalamu wa hali ya hewa wametengeneza kiwango cha baridi ya upepo kwa kutumia uhusiano wa hisabati unaoonekana katika meza inayojulikana kwa mtaalamu yeyote mzuri wa hali ya hewa. Jedwali hili huzingatia vigezo viwili vikuu, joto la hewa, na kasi ya upepo, hasa ili kutathmini athari za mwisho juu ya wa kwanza. Hii ni kawaida katika maeneo yenye hali ya hewa mbaya sana kama vile Canada na maeneo ya kaskazini, lakini pia inaweza kutumika katika maeneo fulani nchini Uingereza. Ni muhimu kujua kwamba kadiri joto lilivyo chini, ndivyo upepo unavyoimarisha hisia ya baridi. Madhara ya upepo juu ya joto hupimwa na index ya upepo (kwa mara nyingine tena, hakuna kitu cha kufanya na turbine ya upepo), ambayo ni idadi bila vitengo. Kwa mfano, ikiwa joto ni 0 ° C na upepo unavuma kwa kasi ya 40 km h, kiwango cha baridi ya upepo itakuwa -6 ° C. Kwa maneno ya moja kwa moja, hii inamaanisha kuwa joto la wazi litakuwa -6 ° C bila upepo. Unaweza kuwa umedhani, lakini sasa unaelewa kanuni: kasi ya upepo (haijalishi mwelekeo wake) ina ushawishi mkubwa juu ya joto la mwili wa binadamu. Upepo unapokuwa mkali zaidi, ndivyo unavyohisi baridi zaidi. Kwa hiyo fikiria upepo unaovuma unapofikiria mavazi utakayovaa! Kwa nini usichukue hatua za kukagua hali ya hewa ili kuhakikisha kwamba hakuna kosa?