All Questions
Tagged with weather or meteorology
1,216 questions
6
votes
1
answer
1k
views
ERA5 Data - How is a wind gust defined?
I'm working with wind data, that I buy from a company, which delivers basically reformatted ERA5 weather data from ECMWF (https://www.ecmwf.int/). Their historic wind data includes "Wind gusts (...
- 205
2
votes
1
answer
139
views
Air pressure, fronts and temperature
I have spent hours on this topic and I seem unable to make sense of it.
If air moves from high pressure toward low pressure, and wind is the movement of air due to differences in pressure, how can, ...
1
vote
0
answers
56
views
Why are rainy seasons different in different locations?
I noticed that the Middle East's rainy season generally runs from November to May; but Florida, which is at almost the same latitude, is exactly the opposite, peaking from May to November. Can anyone ...
- 11
1
vote
1
answer
77
views
What other statistics can I calculate with the weather statistics I already have?
Ok, so I'm making a data set that correlates the beer consumption level of a country to the weather of the country, but the weather statistics I have don't correlate as much as I would like.
These ...
3
votes
0
answers
48
views
What are (meteorolgical) land depressions?
Reading the Wikipedia page for some North Indian Cyclone Seasons I've come across multiple systems called "land depressions". (written as Land [number])
Example (Land 01 2019):
I'm not ...
- 31
5
votes
0
answers
169
views
Why does Hurricane Ian show a long tail off to the North-East on doppler radar?
I was looking at the radar on the Weather Channel website and I noticed something that I don't think I've ever seen before.
Screen shot from 11:30 AM EST 9/29
Hurricane/Tropical Storm Ian can be seen ...
- 151
1
vote
2
answers
130
views
Measure of daylight brightness
I am looking for a meteorological measure of daylight brightness/luminosity. I can only find measures that are defined by the number of hours of sunlight during a day, but is there a measure that also ...
- 111
4
votes
1
answer
755
views
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 ...
- 43
1
vote
2
answers
235
views
In geostrophic wind, what is the mechanism behind the tendency of the coriolis effect/force and the pressure gradient force to balance each other out?
I understand that it is possible for the coriolis effect and the pressure gradient force (PGF) to cancel each other out, but it appears to be a tendency (rather than just a possibility). What is the ...
- 143
1
vote
0
answers
50
views
Applying spline interpolation for Brunt-Vaisala frequency
I have taken an upper air sounding from UoW Database and currently calculating the Brunt-Vaisala frequency (the 'squared' one, at the moment) using MetPy across several stations for some basic ...
- 41
1
vote
0
answers
143
views
What does "red sun at night, sailor's delight" mean and is it true?
There is proverb that sounds like:
Red sun at night, sailor’s delight; red sun in the morning, sailor
take warning.
Is it valid and if it is then what is it about?
- 141
2
votes
0
answers
434
views
How do I calculate the Madden-Julian Oscillation (MJO) phase from RMM1 & RMM2? [closed]
I want to calculate the Madden-Julian Oscillation (MJO) phase by myself using Real-time Multivariate MJO series 1 (RMM1) and 2 (RMM2) from a data file.
The formula for doing so is:
$MJO phase = \...
- 21
9
votes
3
answers
10k
views
Why is the Coriolis effect zero near the equator?
I came to know that Coriolis effect is maximum at the poles and negligible at the equator. I could not figure a logical meaning behind it. Could someone please explain? Also, does it have anything to ...
6
votes
1
answer
618
views
What is the name and effect behind this circular cloud phenomenon?
The picture of this cloudy sky was taken today in Hamburg, Germany. Any idea, what it is, where it comes from and if it has a special name?
- 161
0
votes
0
answers
61
views
Map showing the typical rainfall paths
Hello I am looking for a map that shows the typical (typical for the last 50 years) precipitation paths in the Northern Hemisphere! I already know this map, but it only shows a momentary event and ...
- 2,065
3
votes
0
answers
27
views
What is the effect of increasing the size interval in the generalized dynamic equation (GDE) to simulate an evolving aerosol?
The following differential equation allows me to calculate the the number concentration of aerosol particles from 2 nm to 3 nm.
$$\frac{dN_2{_-{_3}}}{dt}=J_2-J_3-N_2{_-{_3}}.CoagS_2{_-{_3}}$$
In the ...
- 31
4
votes
1
answer
224
views
How to estimate a hurricane's wind speed in mph from other factors?
A formula was given by Brian Norcross but I wanted to know what others thought of this formula:
Hurricane Sustained Winds (mph) = 9.615 * (1015.8 - central pressure [mb])0.6143
3
votes
1
answer
1k
views
What is a wind chill formula that will work from -10 C to +50 C and uses wind speed in km/h?
I'm looking for a wind chill formula that will work from -10 °C to +50 °C and uses wind speed in km/h so that I can use this formula to add this element to a weather station I am programming. I don't ...
- 51
7
votes
1
answer
1k
views
Underground temperature record
Max/min Thermometer readings from a weather station with Stevenson screen are subject to noise from many sources and represent the max/ min at that one point in space.
It's well known that underground ...
- 615
2
votes
0
answers
387
views
Predicting the weather with temperature and humidity
I basically want to make this same idea:
Weather forecast based on pressure, temperature and humidity only (for implementation in Arduino)
without the pressure sensor.
I have a DS18B20 and a HR202 to ...
- 51
5
votes
0
answers
78
views
Confusion about the horizontal pressure gradient force being equal to the gradient of the geopotential in pressure coordinates
I asked this in the physics exchange and thought I would ask here as well:
I see many sources in atmospheric dynamics express the following:
$\frac{1}{\rho}(\nabla p) = \nabla_p \phi$
For example this ...
- 163
3
votes
0
answers
14
views
Empirical adjustment factors for generating sub-daily precipitation values (for IDF curves)
I am trying to generate an Intensity-Duration-Frequency (IDF) curve using 6-hourly precipitation data. These curves are used to estimate the return period for a rain event with a specific intensity (...
- 31
1
vote
1
answer
203
views
Could a nuclear explosion in the Atlantic Ocean during the hurricane season trigger a hurricane?
I am wondering if denotating a nuclear bomb in the Atlantic Ocean during the hurricane season could trigger a hurricane.
For example, say that a 100-megaton bomb was loaded onto a ship and that ship ...
user23275
3
votes
2
answers
505
views
At what latitudes does the precipitation water for Europe evaporate?
I'm currently wondering at what latitudes the precipitation water for Europe evaporates. For some reason I can hardly find any data on where the source of the vapour can be, which is then transported ...
- 2,065
3
votes
0
answers
345
views
Best method for weather station data interpolation with external parameters
I'm part of an organization maintaning a large network of weather stations (~3000 stations) over a European country.
Besides storing data measured from the stations into a database, we also produce ...
- 471
3
votes
2
answers
643
views
What causes "Smokey" weather?
Today when I woke up there was fog in the air and it smelled like smoke, I thought the fog was water vapor since the temperature was 47°C ( I know that's crazy hot), but then when I saw the weather ...
- 31
1
vote
1
answer
111
views
divergence of static stability identical parameters
All,
The static stability of the atmosphere is defined as:
$\sigma =-\dfrac{T}{\theta} \dfrac{d\theta}{dp}= \dfrac{dT}{dp}-\dfrac{R}{c_p} \dfrac{T}{p}$
where:
$T$ is temperature,
$P$ is pressure,
$R$ ...
- 111
4
votes
1
answer
90
views
Where does this refractive index formula come from: $n_{1} = n - 1 = \frac{77.6P}{T} 10^{-6}$
In this equation, $n_{1} = n - 1 = \frac{77.6P}{T} \cdot 10^{-6}$ the variable P is the total air pressure and T is expressed in Kelvin. This equation describes the refractive index of moist air as EM ...
- 51
1
vote
0
answers
35
views
What does the refractive index static coefficient measure and how is it derived?
From my understanding the refractive index structure coefficient $C_{n}^2$ measures atmospheric turbulence, but I'm not entirely sure as the literature seems to imply that there are slightly different ...
- 51
6
votes
1
answer
1k
views
Why does the jet stream meander?
I wanted to explain to high school students why the jet stream meanders, I am aware of the equations describing relative vorticity and planetary vorticity, the concept of conservation of vorticity i.e....
- 61
4
votes
1
answer
145
views
What is a Tropical Forcing and is it related to Climate Forcing?
I see the term Tropical Forcing used in weather synopses but have been unable to find a concise definition of the term. Also, is "Tropical Forcing" a different concept than "Climate ...
- 41
4
votes
2
answers
799
views
On geostrophic wind. How can the Coriolis force cancel out the pressure gradient force when they are mutually perpendicular?
If we are in Northern Hemisphere and there is a point where there is a high pressure, denote it by H, and there is a point where there is low pressure, denote it by L, (for simplicity assume them to ...
- 101
2
votes
0
answers
26
views
Compute upwind flux for gridded data
I'm trying to compute something called the "Drying Ratio" following: Eidhammer, 2018
The drying ratio is the ratio of the precipitation to the incoming vapor flux. So,
$DR = \frac{F_{in} - ...
1
vote
1
answer
89
views
How might 25% lower gravity affect precipitation on an Earth-like planet? [closed]
I'm working on a science fiction project and hoping someone who knows something about climate can answer this question for me: if Earth had 25% less gravity, how would that affect precipitation? I ...
- 233
4
votes
0
answers
67
views
Visible satellite imagery, atmospheric anomaly (descending air) in cumulus fields?
When looking at GOES satellite imagery, in the visible channels. I have noticed these "lines" if you will, usually forms in Cumulus fields. I understand the process of the 'Mackerel sky' (...
- 41
7
votes
1
answer
1k
views
How do meteorologists accurately measure outdoor air temperature? There's sunlight, local trapping of air, radiant heat, precipitation
I'd like to know how the state-of-the-art meteorological direct, localized measurements of the temperature of the air is measured.
If you put a thermometer in sunlight it may read high. If you put it ...
- 6,904
2
votes
0
answers
36
views
Which atmospheric parameters will give accurate result of electricity consumption of an area by using multiple regression model?
I have a dataset that gives values of
temperature,
Relative humidity
Geopotential
Ozone mass mixing ratio
Potential vorticity
Fraction of cloud cover
Specific cloud ice water content
Specific cloud
...
- 21
1
vote
0
answers
415
views
I'm trying to create a interactive matplotlib figure with a dropdown menu on a tkinter popup window but nothing displays
So I'm trying to create dropdown menu that loads different goes satellite data but when i embed the code to my code nothing displays but it displays perfectly on Notebook and yes i am using Visual ...
4
votes
2
answers
120
views
Estimating meteorological visibility from air chemical and particulate composition
I have found here an answer that provides formula that only takes into account vapors, pressure and temperature - What is the formula used for atmospheric visibility?
Is there an approach that also ...
- 59
3
votes
0
answers
57
views
Does Environment Canada offer archived radar data in gridded format like in the US?
I have seen social media-rologists (weather weenies on Twitter) using the Weatherscope app to display data from the Canadian radar network, which was recently upgraded to dual-pol. For many years, ...
- 895
2
votes
0
answers
96
views
How can i display NEXRAD data in 3d on matplotlib
How do i get nexrad data from KHGX (Houston) in 3D to display in matplotlib
20
votes
2
answers
6k
views
In the northern hemisphere summer, why are places in the north cooler than those in the south?
As the Earth's axis is inclined, during summer in the northern hemisphere places in the north are exposed to the Sun's rays for longer, so days are longer during summer (say in June - Aug). Yet, ...
- 301
3
votes
0
answers
45
views
gridded air pollution data for Japan
Do you know of any database where I can get past air pollution (sulfur oxides (SOx) - nitrogen oxides (NOx) - photochemical oxidants (Ox) - particulate matter (PM) - suspended particulate matter (SPM) ...
6
votes
2
answers
105
views
What kind of clouds did Joseph Kittinger see at 102,000 ft?
When Joseph Kittinger in Excelsior III dwelt at his peak altitude of 102,000 ft (31 km), he reportedly saw clouds at his altitude. What in the world could these clouds have been? Polar stratospheric ...
- 111
2
votes
0
answers
59
views
EOFs T mode vs S mode
Do you know what is the difference between EOFs S mode and T mode? I want to find the spatial patterns and I have a time series for values at each location.
Thanks in advance!
- 51
3
votes
0
answers
82
views
Plot maps from principal component analysis to geopotential height
I want to apply PCA to geopotential height (obtained from ERA5) to find the patterns. The way have created the dataset is: The columns are different locations (latitude/longitute) and the rows are ...
- 51
2
votes
0
answers
81
views
Empirical quantile mapping
I'm not sure if this is the right section to post this, but since it's about weather and statistics I am posting it here first.
I tried using R's qmap package to do a simple experiment using this ...
- 321
1
vote
0
answers
62
views
Where can I live if I like long periods of consistent rain?
Let me elaborate on what I mean by "long periods of consistent rain".
I currently live in London and contrary to popular belief, it's not rainy. When it rains, it's usually only for 20 ...
- 151
5
votes
1
answer
538
views
Why does cold air inflow in high tropospheric layers create a low in the upper troposphere?
As part of my pilot ground examination I got a question about cold-air inflow to the upper layers of the troposphere, the question was about the result of the inflow, The right answer was that it ...
- 183
1
vote
0
answers
32
views
Is the current tropical depression headed towards Taiwan unusually early for the season? (April 7, 2022 at 4.0N 148.0E)
Taiwan's Central Weather Bureau's Current Western North Pacific Tropical Cyclones page shows a tropical depression with the following information:
TROPICAL DEPRESSION
TD02
Position 061800Z at 4.0N ...
- 6,904