Questions tagged [humidity]
The level of water vapor in the atmosphere. Use this tag for questions about either relative or specific humidity.
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At 100% relative humidity, why does the air still feels dry?
At 100% relative humidity, the dew point temperature is the same as the current temperature. One would probably conclude that water would start condensing on surfaces.
But seems that is not always the ...
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Is there such a thing as a "warm wind"?
Sometimes, people say things like "It's only $5^\circ\mathrm{C}$ outside, but there is a warm wind, and it feels much warmer" (I live in Austria, a region where there are Föhn winds). I have ...
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Why is U used for relative humidity in atmospheric measurement equipments?
RH is the symbol of relative humidity in many textbooks. But, in my experience, U is often used in atmospheric measurements. For example, Vaisala PTU300 means pressure, temperature and humidity.
I ...
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Why are eastern Oregon and southeastern Washington so dry?
Why are eastern Oregon, southeastern Washington and southern Idaho so arid, as compared to the humid and lush western Oregon and Washington? In Oregon and Washington there is quite an abrupt boundary ...
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Dew-point temperature and absolute humidity
I am looking for a reference (e.g. book, peer-reviewed paper) that asserts that
absolute humidity is "equivalent" to the dew-point temperature.
Such statement should be true, AFAIU. Online, ...
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How to calculate wet bulb globe temperature (WBGT) using only temperature and humidity?
Greetings fellow scholars,
I'm trying to answer the question above because I've come across WBGT calculators like this one (https://www.climatechip.org/heat-stress-index-calculation) and I don't ...
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How to get specific humidity through absolute humidity and height above ground
I'm trying to make a weather simulator using the article Interactive Meso-scale Simulation of Skyscapes. It gives the formula for calculating the mean static energy:
$$MSE_i = C_p \cdot T_i + g \cdot \...
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What is the "average relative humidity" of the Earth's atmosphere?
What is the current ratio of the amount of water in the Earth's atmosphere compared to its moisture storage capacity?
I see values like "a half" or "70% on various web pages, but can't ...
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Is good rainfall in the UK the result of being a small island surrounded by large moving seas, having mountains and trapped salt [closed]
If the mountains were levelled and salt removed would the country experience as much rainfall?
Context
Damp in houses:
Salt absorbs moisture: think of plaster walls that grow mould from proximity to a ...
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What is the definition for a hyper-humid area?
We can use the aridity index $\left ( ai = \dfrac{P}{PET} \right )$ to define arid areas. Hyperarid areas have $ai < 0.05$. Is there a similar threshold for hyper-humid regions?
Would it be 20 (...
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How has relative humidity changed due to climate change and in which regions?
It is widely known that air temperature is increasing but relative humidity is decreasing in many regions. I wonder why that is, because at higher temperatures more water should evaporate?
Does the ...
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How to convert specific humidity ERA5 in kg/kg to g/kg or mm/day?
The specific humidity of ERA5 data is kg/kg, but some articles work with this variable in g/kg.
How can I convert this?
Or to compare with precipitation, evaporation, and other variables, how to ...
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ERA5 Single Level - Calculate relative humidity
for ERA5 hourly data on single level relative humidity can not be downloaded. However, dewpoint temperature is given and in the description it is stated that "combined with temperature and ...
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Is "humidity" the quantifiable metric for mugginess?
I've always described somewhere as "humid" if the air feels very moist and muggy. So, in the US, I'm thinking of places like Texas (e.g., Houston) and Florida (e.g., Miami). I would consider ...
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What are some reasons for Aridification
I an working on a Si-Fi world, and am looking for ways that an area would, over a long timescale, lose the majority of its water. I understand how the lose of vegetative cover due to climate changes ...
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Pressure vs Temperature effect on humidity
I am a bit confused about pressure vs temperature effect on relative humidity.
I know that air density is decreased with altitude, which means that there is more "space" between air ...
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Meterological measures -formula containing temperature, humidity, cloud, wind
I am looking for a meteorological measure (formula) of something which combines 2 or more of the following:
temperature,
humidity,
cloud,
wind,
precipitation,
UV
I have searched, and for example, ...
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Is there a bigger diurnal temperature variation in the summer because of a greater humidity?
It seems there is a greater variation in temperature during summer than during winter (image: maximal and minimal temperatures in Britain - source).
My hypothesis is that this is because there's a ...
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Why would it be drier indoors during the winter vs the summer?
Yesterday during the day, inside my house it was 16% relative humidity. Outside it was 69% relative humidity and cold, around 35 degrees Farenheit. It is always 72 degrees Farenheit inside the house.
...
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What is the difference between surface specific humidity and surface relative humidity?
What is the difference between surface specific humidity and surface relative humidity (it's wetter and dryer respectively)? The trends, according to the latest IPCC report, are opposite for the two, ...
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What Pa level should I use when looking at Relative Humidity data from CMIP6 models?
I have downloaded a number of future simulations for a group of GCMs from CMIP6 for the variable Relative Humidity (hur).
I chose the 100000pa level to view the RH data in panoply for the EC-Earth ...
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How can I deal with unrealistic Relative Humidities being calculated using vapour pressure and saturated vapour pressure?
I am calculating RH (%) using this well accepted equation:
$RH =e \times \frac{100}{es(T)}$
where $e$ is the vapour pressure and $es(T)$ is the saturated vapour pressure at temperature $T$.
I have ...
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Incorrect relative humidity with SHT30 when comparing to dry and wet bulb calculation
I am attempting to calculate wet bulb temperatures needed for agricultural curing processes. I am trying to do this by inferring the wet-bulb value from relative humidity and dry bulb temperature.
The ...
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How does a whirling hygrometer work, how does it differ from static dry/wet bulb thermometer, and how to obtain humidity from its readings?
Answers to my previous question How is relative humidity determined from a wet and dry bulb readings? provide equations for converting the two temperature measurements to a relative humidity.
In ...
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How to convert Relative humidity (%) or Specific humidity (kg/kg) to Air humidity (mb)?
The model I use needs the data of Air humidity and unit is 'mb' (there is no other explanations about this variable), but now I only have two datasets and there are Relative humidity (%) or Specific ...
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Why does relative humidity drop if I open the window in winter? What about the temperature drop?
I understand that 40% rel. hum. at 0 °C is less absolute humidity than 40% at 20 °C. However, assume that we have 2$~m^3$ of air. Both are 40% humid at 20 °C. Now we exchange 1$~m^3$ with air that is ...
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How to calculate the specific humidity based on the saturated specific humidity?
I am using ERA5 data to drive the land surface model. One of the forcing required by LSM is specific humidity. We want to use the 2-m specific humidity. So how can I calculate the specific humidity ...
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Relative Humidity approximation from Dew Point and Temperature
I would like to find a formula to approximate RH based on known air temperature and dew point. I need the approximation to be valid at least between -20...+40 degrees Celsius. I read the accepted ...
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What does supersaturation with respect to ice mean?
I've been reading about the Bergeron process, a process that generates much of the precipitation in the middle latitudes by generating ice crystals at the expense of water droplets. The part I don't ...
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How do the pros measure humidity?
I have used a wet/dry bulb setup to estimate humidity, and it appears that the Argentinian meteorological service uses one in Antarctica as well.
Wikipedia sez:
Humidity measurement is among the ...
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How is relative humidity determined from a wet and dry bulb readings?
The question What is the second thermometer in the image from the Esperanza Antarctic temperature record? shows what might be a wet/dry bulb setup.
I've given one to a friend to measure humidity for ...
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Finding free humidity data
I am trying to find historical humidity levels (ideally in percentage format) across the globe divided by sub-country regions or more granular.
The time granularity would be daily, but hourly would ...
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What the humidity metric is hiding?
So I have been spending time in Moscow Russia which essentially records very similar climatic humidity to my home city of London. However in Moscow my throat is permanently dry, I need to consume more ...
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Deserts and Humidity
How is that a general rule of thumb that less humidity equals more rain? Deserts don’t get much rain and humidity is also very low. Rainforests get a lot of rain when the humidity is very high so how ...
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Humidity and Rainfall
Usually the higher the humidity the more rainfall we get like in the summer here in Asheville, North Carolina we get a lot of showers and thunderstorms in the summer from the high humidity but I saw ...
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How does this calculate the water transport between crops in the webside?
click->http://gpe.letsgrow.com/
next click->moisture transport
In the results of Moist transport through the crop, what is the relationship between crop height and diffusion, air movement, and total ...
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Definition of Surface-based atmospheric duct
I am writing a literature review for a project and I have a problem. Namely, I cannot figure out the the condition required for surface-based duct to occur. Literature does not help either. In one of ...
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Oscillating dew point throughout the year?
I was searching for the climate of Saudi Arabia and I noticed that the city of Abha (altitude of 7000 feet) has a "strange" behavior in its dew point, as numbeo suggests: https://www.numbeo.com/...
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How does total pressure affect relative humidity and how do I correct my hygrometer for pressure?
Obviously pressurized air can hold more water than regular air, so an increase in overall pressure would result in an inversely proportional decrease in relative humidity. However, I can't seem to ...
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How to calculate relative humidity from temperature, dew point, and pressure?
Is there a formula given the temperature, dew point, and pressure to find relative humidity?
I have seen several calculators like this one, but I would like to know how to calculate this myself.
I ...
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Can minimum relative humidity be greater than maximum relative humidity?
I am trying to calculate minimum and maximum daily Relative Humidity values given a min/max Specific Humidity and min/max Temperature.
I found some equations here that work with the given variables, ...
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How to predict when contrails are likely to form over a specific location using public data?
I saw the image below used as a click-attractor to an unrelated story about tourism, but found a larger version here.
Contrails, or water condensation trails happen when planes pass through the ...
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Why does warm air "hold" more moisture?
It is often explained that warm air holds more water because warmer water is less likely to condense. This and other explanations just seem to be circular arguments. If the warmer air picks up enough ...
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How is the specific heat of a wet bulb determined?
I am quite new to the psychrometry and the study of humidity, and I'm currently learning about the dry-bulb wet-bulb thermometry. As far as my understanding goes, the wet bulb is connected to a source ...
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Water vapor content versus specific humidity
I am wondering the difference between water vapor content and specific humidity to determine the moisture availability in the atmosphere. Which one is more acceptable variable to determine the ...
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How would I use data to find specific humidity and mixing ratio?
I keep reviewing this table to compare and contrast my results:
The parcel of air is at 35°C and a relative humidity of 43%.
I used this online calculator and it stated that with these two factors ...
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How to calculate humidity using outside temperature and outside relative humidity?
I would like to ask how to calculate the relative humidity that a heated indoor area would have using only outside temperature and outside relative humidity.
I found the Relative Humidity Calculator ...
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Is this an accurate simulation of a further south Australia with a filled lake Eyre?
I created this climate map based on a simplified Koppen Climate Classification map (shown below). In this scenario Australia is moved 10 degrees of latitude further south and the Lake Eyre basin is ...
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Why a stratus cloud does not always reach all the way to the ground?
The surface of the ground at night cools down because of outgoing long-wave radiation. In my understanding the cooling of the surface also causes cooling of the adjacent air. If the air contains ...
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What is the mixing ratio of a cloud?
A cloud has relative humidity of 100% or more. Is it correct to say that the mixing ratio of a cloud is undefined? My reasoning is that dry air in a cloud is negligible therefore $w = \frac{x g}{ 0 kg}...
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