Climate - Relation between temperature and humidity | badz.info
Relative humidity describes the percentage of water vapor in air that changes as Values such as relative humidity and dew point help describe these effects on weather. The Relationship Between Moisture & Temperature. How do you calculate relative humidity from temperature and dew point? What is the relationship between high relative humidity and a feeling of discomfort in. Dew point temperature is defined as the temperature to which the air would have to cool Relative Humidity can be inferred from dew point values. is a large difference between air and dew point temperatures, which indicates air with lower.
Exercise regimens need to take into account temperature and humidity to avoid health risks. This is because the human body relies on evaporation of sweat to lead to cooling. If the air is both hot and humid, the body cannot evaporate the sweat as effectively, which can lead to dehydration, overheating and even death. Like in arid conditions and high heat, hydration becomes key.
Humidity | North Carolina Climate Office
Recent studies reveal connections between humidity, temperature and public health. Temperature and humidity directly influence influenza virus transmission in temperate regions of the world.
Influenza activity increases in winter in each hemisphere's temperate zones. Flu virus thrives when outdoor temperatures grow colder. While winter relative humidity is higher in winter, indoor relative humidity is much drier due to heating. The exposure to cold outside air and dry inside air increases flu virus transmission.
Research indicates aerosolized influenza virus is more stable at lower relative humidity. The half-life of the virus drops at higher temperatures and cannot be spread as easily.
Additionally, temperature and humidity make people more susceptible to influenza infection. Surprisingly, there is no significant difference in daily average relative humidity between summer and winter. Since warm air is less dense than cold air, there is more room for water vapor in warm summer air as compared with cold winter air.
Figure B From www. The dew point is the temperature to which the air would have to be cooled to become saturated. Below the dew point, water will condense out of the air onto surfaces.
In the early morning, grass surfaces will be coated with water if the nighttime temperature has dropped below the dew point. How does this relate to agriculture? People keep cool by perspiring. Figure C From http: When humidity is low, and dew points are in the 50s and low 60s, moisture evaporates from plants very quickly. Average relative humidity The average relative humidity for July reveals the humidity provinces of the Northern Hemisphere when aridity is at a maximum.
At other times the relative humidity generally will be higher. The humidities over the Southern Hemisphere in July indicate the humidities that comparable regions in the Northern Hemisphere will attain in January, just as July in the Northern Hemisphere suggests the humidities in the Southern Hemisphere during January.
A contrast is provided by comparing a humid cool coast to a desert. The midday humidity on the Oregon coast, for example, falls only to 80 percent, whereas in the Nevada desert it falls to 20 percent. At night the contrast is less, with averages being over 90 and about 50 percent, respectively. Although the dramatic regular decrease of relative humidity from dawn to midday has been attributed largely to warming rather than declining vapour content, the content does vary regularly.
In humid environmentsdaytime evaporation increases the water vapour content of the air, and the mixing ratio, which may be about 12 grams per kilogram, rises by 1 or 2 grams per kilogram in temperate places and may attain 16 grams per kilogram in a tropical rainforest.
In arid environments, however, little evaporation moistens the air, and daytime turbulence tends to bring down dry air; this decreases the mixing ratio by as much as 2 grams per kilogram.
Humidity also varies regularly with altitude. On the average, fully half the water in the atmosphere lies below 0. The transparent air surrounding mountains in fair weather is very dry indeed. Closer to the ground, the water vapour content also changes with height in a regular pattern.
Evaporation and humidity Evaporation, mostly from the sea and from vegetation, replenishes the humidity of the air. It is the change of liquid water into a gaseous statebut it may be analyzed as diffusion. The rate of diffusionor evaporation, will be proportional to the difference between the pressure of the water vapour in the free air and the vapour that is next to, and saturated by, the evaporating liquid.
If the liquid and air have the same temperature, evaporation is proportional to the saturation deficit. It is also proportional to the conductivity of the medium between the evaporator and the free air.
If the evaporator is open water, the conductivity will increase with ventilation. But if the evaporator is a leaf, the diffusing water must pass through the still air within the minute pores between the water inside and the dry air outside. In this case the porosity may modify the conductivity more than ventilation. Global distribution of mean annual evaporation in centimetres. The temperature of the evaporator is rarely the same as the air temperature, however, because each gram of evaporation consumes about calories 2, joules and thus cools the evaporator.
The availability of energy to heat the evaporator is therefore as important as the saturation deficit and conductivity of the air. Outdoors, some of this heat may be transferred from the surrounding air by convection, but much of it must be furnished by radiation. Evaporation is faster on sunny days than on cloudy ones not only because the sunny day may have drier air but also because the Sun warms the evaporator and thus raises the vapour pressure at the evaporator.
In fact, according to the well-known Penman calculation of evaporation an equation that considers potential evaporation as a function of humidity, wind speed, radiation, and temperaturethis loss of water is essentially determined by the net radiation balance during the day.