Questions tagged [humidity]
The level of water vapor in the atmosphere. Use this tag for questions about either relative or specific humidity.
46
questions
2
votes
2answers
46 views
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 ...
7
votes
3answers
170 views
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 ...
5
votes
1answer
100 views
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 ...
0
votes
0answers
22 views
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 ...
3
votes
1answer
111 views
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 ...
0
votes
2answers
83 views
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 ...
0
votes
1answer
76 views
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 ...
1
vote
0answers
35 views
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 ...
0
votes
1answer
32 views
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 ...
4
votes
0answers
41 views
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/...
2
votes
1answer
74 views
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 ...
2
votes
1answer
3k views
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 ...
1
vote
1answer
198 views
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, ...
5
votes
1answer
148 views
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 ...
10
votes
3answers
7k views
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 ...
3
votes
0answers
246 views
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 ...
1
vote
1answer
539 views
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 ...
5
votes
1answer
864 views
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 ...
6
votes
1answer
2k views
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 ...
2
votes
0answers
1k views
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 ...
2
votes
1answer
77 views
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 ...
0
votes
1answer
924 views
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}...
2
votes
5answers
671 views
Why does relative humidity seem to correlate with high temperature (at least where I live)?
I live in New Jersey. Now that summer is coming on us, temperatures and outdoor relative humidity are both increasing. I've noticed the few years that I've lived here that there seems to be a rough ...
6
votes
3answers
736 views
Is there a name for these “pouring” clouds?
I snapped this photo with my phone flat against the window of a bus, facing south while traveling west across a bridge in New Taipei City. I'd say it was at about 24.995N, 121.438E. It was about 14:00 ...
3
votes
1answer
1k views
Why do anticyclones bring clear skies in summertime?
It's obvious that in summer anticyclones bring hot weather. But why clear skies?
Heat evaporates the moisture and should lead to the cloud formation, shouldn't it?
3
votes
1answer
2k views
How does humidity vary with height in the Earth's atmosphere?
I am busy with the development of an "environment" model that can be used for flight simulation of all kinds of flight vehicles — ranging from quad-copters, unmanned aerial vehicles, manned aircraft, ...
13
votes
1answer
587 views
Why (actually) is the night sky so bright in the city? How far up is that happening?
The recent news reported by the New York Times, the BBC and the NPR web sites (for example) as well as in the Iceland Review and Iceland Magazine sites, about the shutting-off of Reykjavik's ...
0
votes
1answer
750 views
Mild climate, low-humidity city all year round [closed]
Where in the world can I find a place with mild / warm and non-humid climate all year round?
What I'm looking for is a city with these characteristics:
- monthly average low temperature > 5°C (41°F)
-...
4
votes
2answers
7k views
Can relative humidity be over 100% near (within 30-60m) the surface?
I am processing a big meteorological data set, which is a global forcings dataset derived by other datasets and observations, and calculating relative humidity from qair,temperature, and pressure ...
3
votes
3answers
7k views
Is it hotter in different places with the same air temperature?
I am from (and live in) Minnesota, USA. In the summer here it always reaches temperatures in the 90s (F) for periods of time but not every week. The humidity is often high and the dew point often ...
1
vote
1answer
73 views
How strong is the correlation between the dew point of a town and the seawater temperature next to that town?
For example, the towns that has the highest dew point are usually next to the Red Sea and the Persian Gulf where the seawater temperature exceeds 30 degrees in summer.
3
votes
1answer
469 views
Accurately Measuring Indoor/Outdoor Air Temperature & Relative Humidity
I’m conducting an independent study as a concerned citizen on the indoor temperature at an animal shelter to support the need of improved air conditioning by documenting how hot it can reach during ...
4
votes
2answers
2k views
Does usual city pollution have effects on relative humidity?
I've noticed that in a rural area with low pollution the relative humidity is constantly lower than the humidity in a high polluted city. Is there any correlation between pollution and humidity?
5
votes
2answers
5k views
Why doesn't it snow even when it is below freezing?
I know the temperature of a place is determined by various factors, a few of which I can think of are: Altitude, distance from sea, latitude, wind etc.
My question is basically regarding latitude. ...
4
votes
0answers
30 views
Can humidity changes induce stacking-sequence changes?
My understanding is that some minerals with layered crystal structures will reversibly absorb water with changes in humidity. Are there any minerals where this reversible absorption leads to a ...
8
votes
1answer
17k views
How to calculate specific humidity with relative humidity, temperature, and pressure
I know there is this question already How do I convert Relative Humidity into specific humidity
but I don't have ρws = density of water vapor (kg/m3) and ρ = density of the moist or humid air (kg/m3)....
6
votes
1answer
889 views
Specific humidity range in tropical lowlands?
I am running a land biosphere model that uses meteorological data as drivers. The model has a threshold of 32g/kg for specific humidity. The data I am using taken from a reanalysis performed by J. ...
30
votes
2answers
48k views
At what humidity does it start to rain?
As far as I understand it is perfectly valid for air to have 100% humidity. At that point, all water can still exist in form of vapor, non-condensed.
Does it immediately start to rain if humidity is >...
10
votes
3answers
8k views
What does the notation “kg kg-1” for units mean for specific humidity
I am using a data set from Justin Sheffield at Princeton that includes specific humidity. The description is as follows:
"Reanalysis 6-hourly specific humidity interpolated to 1.0deg with account ...
4
votes
1answer
641 views
How and why humidity and vapour pressure change as a parcel of air with an unchanging amount of water vapor rises, expands, and cools
I know that a parcel of air can rise, cool and create clouds and rain but I'm struggling to understand how:
absolute humidity
relative humidity
actual vapour pressure
saturation vapour pressure
...
4
votes
1answer
109 views
Fictional Land - How can I keep dense fog in an area for half a day? [closed]
This question is now here on Worldbuilding Stack Exchange
I am a writer, and this question is for a fictional work. However, given its nature, I believe it is better suited here than Writers Stack ...
7
votes
1answer
319 views
LWC and Absolute Humidity
What is the difference between "liquid water content" and "absolute humidity" in meteorology? Both have units of mass/volume.
10
votes
1answer
1k views
How to calculate relative humidity?
I am involved in developing a weather based application which needs to calculate relative humidity and display it. I grab other weather variables like temperature, precipitation, wind speed and ...
10
votes
2answers
920 views
Why is q used for specific humidity?
$q$ is the symbol used for specific humidity in many textbooks and papers (at least in meteorology and climatology, I'm not familiar with it in other disciplines). Where does this symbol come from, ...
23
votes
3answers
49k views
How do I convert specific humidity to relative humidity?
How do I convert specific humidity to relative humidity? What variables are needed (e.g. air temperature, pressure, etc.)?
9
votes
1answer
486 views
How can I downscale daily values of relative humidity?
I have a dataset (The ISIMIP interpolation of CMIP5 output) that contains daily values of the following variables:
...
