Dewpoint
During the warmer months, we can use the “Dew Point” as useful and interesting discomfort index. This particular weather element gives us an idea of how comfortable or uncomfortable we feel within the framework of hot and humid weather of the summer season. This information can be used at any time in our daily lives.
| What is Dew Point? |
The dew point is the value that should lower the air temperature for the existing water vapor begins to condense.
The dew point can be calculated directly from the data of temperature and relative humidity existing in a given time. These data may come from weather reports issued radially, or registered by instruments. These pages offer readers the table to easily calculate the “dew point”.
Here’s an example. If on a given day, we have our 26th city in temperature and 60% relative humidity, the corresponding dew point (according to the table) is 18. But what are these 18 degrees? Well, if the zone air is rapidly cooled, and the temperature drops to 26 degrees today until the 18th of “dew point” (ie, a decrease of 8 degrees in a few minutes), happen two consecutive weather. First, tiny droplets of liquid water (dew) on all smooth surfaces found outdoors will form. These droplets of dew are those that give the name to “dew point”. Then the condensation will occur also in the air, forming water droplets innumerable suspension, which form a mist.
Therefore, the dew point is the temperature at which a cooling air, mist formation begins, and dew on the objects.
| Influence on Health |
Humans have the physiological ability to maintain constant 36 ° (or 37) to the internal temperature of the body. Simultaneously, the temperature of the skin is usually exposed to the outside of 32 degrees (so long as it is not exposed to sunlight).
We emphasize that a person “feels cold” when your skin temperature drops below 32 degrees. Conversely, the sensation of heat increases when the temperature of the skin begins to overcome the thermal value.
When there is no wind and air temperatures are high, our body has a natural cooling process, tending to prevent heat buildup in the body. The cooling mechanism starts its operation, when the skin begins to perspire. Then, by evaporation of water droplets which constitute the sweat, the skin and the entire body is cooled and the excess heat lost.
Well so what role does our “dew point”?
Meteorologists and doctors have noted that the dew point is very important to measure the ease or difficulty with which the skin sags heat outside the body has too much weather index.
| The “heavy” or uncomfortable weather |
In general, we all say that there is “heavy weather” or “uncomfortable” when we feel suffocated by the heat and humidity. That particular sensation occurs especially in environments with elevated dew point (20 ° or more). These are situations in which, in the absence of wind or air currents, the organism is difficult or impossible to be cooled by the evaporation of perspiration.
| “Comfortable” Values |
On an estimated basis, it has been found that when the air dew point is between 8 and 13th, we experience a high sense of comfort, especially with temperatures of 20 to 26 ° in the shade and in a place without wind .. Son these the most conducive for normal body cooling and this is how our body can best meet their specific functions all weather conditions.
The ideal starting point for human life is the dew 10th. This value exists in the air, for example 30 ° in temperature and 30% humidity, and also with temperature 20 ° and humidity 55% (note Table). Interestingly, when the dew point is 10 °, the actual amount of moisture in the air is 7.5 grams of water vapor per cubic meter of air (at normal atmospheric pressure).
| The “discomfort” climate |
When the room air has a dew point of 20 to 25 °, perspiration is copious people. Then, the discomfort is increasing, and it is said that “time is very heavy.” Discomfort or “heaviness” weather because sweat evaporates with difficulty, or not evaporation and therefore body can not effectively cool a typical value at which starts to become noticeable environmental discomfort is for a value 20 ° in the dew point. This value e (for example) under the following weather conditions.
1) An Evening with 34th temperature and 45% humidity.
2) One night with 26th and 70% humidity.
3) A temperature morning with 22 degrees and 90% humidity.
When our region gets very hot and humid air from the south and center de¡ Brazil and the Argentine North-East, it is in the form of winds North, North East or North West. Under these extreme weather conditions, the dew point can reach exceptional value of 24 °. In this brand up for example in a 36th afternoon sing temperature and 50% humidity; also on a night with 30 and 72% humidity, or in a dawn with 25 and 95 humidity.
Schismatic These conditions often occur in some summer days in the area of Buenos Aires, River Plate and southern coastal waterway.
Once we know the dew point (obtained by means of the table) we can use the box climatic comfort feeling.
|
Dewpoint and the sense of comfort |
| Dewpoint | Designation | General Comment
|
| -5 To -1 | Very dry air | There is a sense of irritability and mild dehydration (especially in strong wind) |
| Oº at 4 | Dry air | Comfortable atmosphere in winter. |
| 5th to 7th | Dry Welfare | Welfare with temperatures 20 to 26 degrees. Pleasant warmth with temperatures of 27-30 degrees. |
| 8th to 13th | Welfare maximum | High sense of comfort and convenience, with temperatures of 20 to 26 ° (no wind and shade). Temperatures of 27 was well tolerated at 30 |
| 14 º to 16 º | Bienevtar wet | Pleasant weather in temperatures of 20 to 26th. A higher thermal markings, heat is becoming uncomfortable |
| 17 º to 19 º | Moist heat | “Heavy” with temperatures of 20 to 26 °. Climate A higher thermal markings, heat is becoming uncomfortable. |
| 20 ° to 24 ° | Sweltering humid heat | Intense feeling of unease and discomfort, especially with temperatures of 30 degrees or more. Danger of “heat stroke.” Sun, danger of heatstroke |
| 25 ° or more | Very humid and intolerable heat | Unhealthy and dangerous weather, especially with thermal marks 30ºc or greater |
