The relationship between relative humidity, temperature and dew point - Chicago Tribune
Relative humidity is at all temperatures and pressures defined as the ratio of the . Absolute humidity is defined as the mass of water vapour in a certain volume. Table 1 the second most influential parameter is air temperature. Air temperature and absolute humidity of air are not entirely independent what can be seen. Temperature and humidity affect the Earth's weather and the health and comfort of its The Relationship Between Moisture & Temperature.
Dew Point When the relative humidity reaches percent, dew forms. Dew point refers to the temperature at which air reaches saturation by water molecules.
Warmer air can hold more water molecules, and as that warm air cools, it loses water vapor in the form of condensation. A higher dew point means higher moisture content for air, leading to uncomfortably humid conditions with cloud and precipitation potential. The air itself is saturated once the dew point matches the air temperature.
People find dew points of 55 or lower much drier and more comfortable than higher dew points. Dew point never exceeds air temperature. The highest recorded dew point stands at 95 in Saudi Arabia in High humidity and heat means more water in the air, which can carry odor molecules further, leading to considerable stench in summer around bacteria sources such as garbage.
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.
The relationship between relative humidity, temperature and dew point
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.
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. See Wikipedia's guide to writing better articles for suggestions. September See also: Precipitation meteorology and Humid subtropical climate While humidity itself is a climate variable, it also overpowers other climate variables.
The humidity is affected by winds and by rainfall. The most humid cities on earth are generally located closer to the equator, near coastal regions. Cities in South and Southeast Asia are among the most humid. Kuala LumpurManilaJakartaand Singapore have very high humidity all year round because of their proximity to water bodies and the equator and often overcast weather.
Some places experience extreme humidity during their rainy seasons combined with warmth giving the feel of a lukewarm sauna, such as KolkataChennai and Cochin in Indiaand Lahore in Pakistan.
Darwin, Australia experiences an extremely humid wet season from December to April.
Humidity - Wikipedia
Shanghai and Hong Kong also have an extreme humid period in their summer months. During the South-west and North-east Monsoon seasons respectively, late May to September and November to Marchexpect heavy rains and a relatively high humidity post-rainfall.
Outside the monsoon seasons, humidity is high in comparison to countries North of the Equatorbut completely sunny days abound. In cooler places such as Northern Tasmania, Australia, high humidity is experienced all year due to the ocean between mainland Australia and Tasmania.
United States[ edit ] In the United States the most humid cities, strictly in terms of relative humidityare Forks and Olympia, Washington. In general, dew points are much lower in the Western U.
Discussion on Humidity
The highest dew points consistently found in the US are found in coastal Florida and Texas. When comparing Key West and Houstontwo of the most humid cities from those states, coastal Florida seems to have the higher dew points on average. However, Houston lacks the coastal breeze present in Key West, and, as a much larger city, it suffers from the urban heat island effect. The record was set during the Midwest heat wave disaster which was characterised by a very strong temperature inversion which caused cloudless skies during this in spite of an apparent world record surface-based CAPE set at the same time.
Greenhouse Effect Humidity affects the energy budget and thereby influences temperatures in two major ways. First, water vapor in the atmosphere contains "latent" energy. During transpiration or evaporation, this latent heat is removed from surface liquid, cooling the earth's surface.
This is the biggest non-radiative cooling effect at the surface. Second, water vapor is the most abundant of all greenhouse gases. Water vapor, like a green lens that allows green light to pass through it but absorbs red light, is a "selective absorber". Along with other greenhouse gases, water vapor is transparent to most solar energy, as one can literally see.
But it absorbs the infrared energy emitted radiated upward by the earth's surface, which is the reason that humid areas experience very little nocturnal cooling but dry desert regions cool considerably at night. This selective absorption causes the greenhouse effect. It raises the surface temperature substantially above its theoretical radiative equilibrium temperature with the sun, and water vapor is the cause of more of this warming than any other greenhouse gas.
Unlike most other greenhouse gases, however, water is not merely below its boiling point in all regions of the Earth, but below its freezing point at many altitudes. As a condensible greenhouse gas, it precipitateswith a much lower scale height and shorter atmospheric lifetime- weeks instead of decades.
Without other greenhouse gases, Earth's blackbody temperaturebelow the freezing point of water, would cause water vapor to be removed from the atmosphere.
Discussion on Humidity
Volume thermodynamics and Density of air Humidity depends on water vaporization and condensation, which, in turn, mainly depends on temperature.
Therefore, when applying more pressure to a gas saturated with water, all components will initially decrease in volume approximately according to the ideal gas law. However, some of the water will condense until returning to almost the same humidity as before, giving the resulting total volume deviating from what the ideal gas law predicted.
Conversely, decreasing temperature would also make some water condense, again making the final volume deviate from predicted by the ideal gas law. Therefore, gas volume may alternatively be expressed as the dry volume, excluding the humidity content.
- Relative humidity to absolute humidity and vise versa calculators