Questions tagged [meteorology]

The study of how the earth's atmosphere works, including weather forecasting. Use this tag for questions about the earth's weather. When asking questions specifically about the atmosphere, also include the [atmosphere] tag.

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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 ...
Oone's user avatar
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Can firecrackers be used to subside thunderstorms due to cumulonimbus clouds

Cumulonimbus clouds are associated with thunderstorms. Firecrackers which go up high in the sky and then burst into glittering show, can such crackers be injected in a cumulonimbus cloud and then ...
lousycoder's user avatar
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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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Why was the flooding in Derna, Libya so catastrophic?

I have watched storm Daniel on the internet while it was in Greece and what I saw was much heavier rain than what came down in Libya. But in Libya, property damage and death toll were much heavier, ...
Gyro Gearloose's user avatar
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Mass weighted vertical average of stream function in python

I have a netCDF file of stream function (psi) having dimension (latitude, level), level is pressure level. There are 5 pressure levels (700,600,500,400,300 hPa). I need to compute the mass weighted ...
Aman's user avatar
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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, ...
Yair Daon's user avatar
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Why do tropical areas have low air pressure?

From the question Why are pressure levels raised on warm days?, my understanding is that the air pressure at surface level is not affected by temperature, as the mass of the imagined air column stays ...
bigfoot's user avatar
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How to explain "Vacuum Cleaner Effect" for upper level PV anomaly?

In Jonathan Martin's Book "Mid-Latitude Atmospheric Dynamics" there is a chapter dedicated to anomalies of potential vorticity (PV). The scenario shown in the image below depicts a situation,...
MichaelW's user avatar
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How to use 1D function metpy.parcel_profile in ERA5 xarray dataset open with dask

I really need help, I'm working on ERA5 hourly data on pressure levels. I've extracted relative humidity and temperature on several atmospheric pressure levels. I use Metpy's '...
nietreil's user avatar
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1 answer
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Why air laterally diverges before entering a cyclone/anticyclone?

I'm a newbie in meteorology so sorry if this is a dumb question. I get the general idea of how cyclones form, but one thing I can't wrap my head around is why must the air diverge laterally when ...
user29373's user avatar
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What is the highest evaporation rate in the world? I know evaporation rates for Australia

I have been searching for the above answer for more than 25 years. I am providing a map of Australia for comparison http://www.bom.gov.au/climate/maps/averages/evaporation/ Is evaporation rate 4000 ...
Tad Soroczynski's user avatar
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How to use CMIP6 to predict windspeed in the future?

I'm very new to climate modelling and forecasting, I have chosen a project to forecast wind energy output in the future using wind speed prediction, I wish to use CMIP6 to predict. But I have very ...
Phil's user avatar
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1 answer
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How is this global temperature chart compiled?

In this BBC News article, there is a chart labelled "Hottest day on record globally - Daily average air temperature, 1940-2023". It shows temperatures that are higher in summer and lower in ...
user29329's user avatar
3 votes
2 answers
67 views

Radially symmetric rainfall radar pattern?

I notice this radially symmetric weather radar pattern over London, UK today. Is this a real weather pattern, or a measurement or model artefact? If it is a real weather pattern, what causes it? The ...
Croad Langshan's user avatar
6 votes
1 answer
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Will the hot Atlantic shape global/local weather and if so, how?

So the Atlantic Ocean exhibits record-breaking temperatures currently with about 1 degree Celsius above-average mean surface temperatures. This article, for example, mentions that a more severe ...
hschoell's user avatar
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Visualization of formation of cirrus vertebratus?

I am trying to understand how Cirrus Vertebratus are formed. My book and many web pages simply say "waves orthogonally to the initial cloud formation direction, in fitting conditions, forming ...
323242323242's user avatar
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1 answer
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Weather record last month in the UK

On 22 June 2023 in my village in LE8, south Leicester, UK, there was a large deluge of rain and my house got lightly flooded - the only time ever in 30 years. I'm trying to make a claim now; the ...
Oliver Walters's user avatar
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Why positive PV Anomaly moves westwards?

In Jonathan Martin's Book "Mid-Latitude Atmospheric Dynamics" there is a chapter about PV anomalies. As an example, a positive PV anomaly is discussed. What is the reason, that high PV is ...
MichaelW's user avatar
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Accurate Rainfall with TBRG

For an accurate flood forecast, up to what height maximum from the ground level one can put the TBRG without any obstacles and still receive accurate rainfall?
pravat kumar senapaty's user avatar
3 votes
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What is the deeper difference between QG Omega equation and QG Height tendency equation?

The quasi-geostrophic $\omega$-Equation is a diagnostic equation for $\omega$ (=dp/dt = vertical motion) in terms of geopotential. It is derived in a few steps by manipulating vorticity and ...
MichaelW's user avatar
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Comparing expressions for Ertel Potential Vorticity and Quasi Geostrophic Potential Vorticity

In Meteorology there is a quantity called "Ertel Potential Vorticity" $q_e$ which is conserved considering isentropic flow ($\theta=const)$: $$\frac{d}{dt}\left(\frac{1}{\rho} \vec \eta \...
MichaelW's user avatar
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Why isn't Summer Solstice plus and minus 90 days the hottest in Northern Hemisphere?

If Summer Solstice around June 21 every year is the longest day of the year and closest to the sun for the Northern Hemisphere (maybe I should say receive the most direct facing sunlight), then why ...
Stefanie Gauss's user avatar
2 votes
0 answers
35 views

Linear and non linear relationship in MET office data - A-level maths

I am looking for relationships between different variables in a set of MET office data. The data set is for the months May to October in 2015 and 1987 in various places in the UK. The variables ...
Bysshed's user avatar
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Is there a relationship between wind direction and the bearing of travel?

We want to move from point A to point B using a balloon. If one knows the wind directions, How can one determine the altitude that will steer the Balloon to the desired location?
Tee's user avatar
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Setting specific humidity vertical profile in an LES

I am working with an LES (Large-Eddy Simulation) model, and I want to define the vertical profile of specific humidity (qt) based on a given temperature profile (thl). However, I am not sure how to ...
bowserilis's user avatar
3 votes
1 answer
73 views

Why is one term missing in the derivation of continuity equation in isentropic coordinates?

In the book by Jonathan E. Martin "Mid-Latitude Atmospheric Dynamics - A First Course" the continuity equation for isentropic coordinates is derived by applying conservation of mass: $\...
MichaelW's user avatar
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Unable to plot wind barbs of scatsat data in a ordered way

I have plotted wind speed and wind direction of scatsat data but wind barbs representing wind direction are plotted random (not in ordered manner.How to rectify this problem?
Yogesh Kumar's user avatar
2 votes
1 answer
38 views

How to download atmospheric/oceanographic data for a given region in the sea?

I am trying to get data of atmospheric temperature, wind intensity and/or atmospheric pressure for a specific region of the sea, since I have ocean bottom pressure data from a fixed instrument (lat,...
Miguel 's user avatar
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1 vote
2 answers
50 views

Historic weather station data with hourly temporal resolution

I'm working with ERA5 weather data and am trying to understand some wind & temperature patterns that I'm seeing in my statistics. In order to do that I'd like to compare with some point ...
squarespiral's user avatar
1 vote
1 answer
54 views

Why is mixing ratio at LCL not the same as for starting condition?

I asked a question regarding mixing ratio and wet adiabatic lifting in https://stackoverflow.com/questions/76244447/why-is-mixing-ratio-at-lcl-not-the-same-as-for-starting-condition. I don't want to ...
MichaelW's user avatar
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Estimation of extraterrestrial radiation for latitudes > 66.5° N/S

I'm posting here for the first time, so I hope not to violate any community-specific rules. In Allen et al. (1998): FAO-56 an equation is presented to estimate extraterrestrial radiation Ra for ...
dimfalk's user avatar
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4 votes
1 answer
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Is equivalent potential temperature constant also for dry adiabatic processes?

Equivalent Potential Temperature, defined as $$\theta_e = \theta \cdot e^{qL/c_pT}$$ with $\theta$ denoting potential temperature and q the specific moisture of water remains constant for wet ...
MichaelW's user avatar
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3 votes
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123 views

What was this historic object used for?

This object is displayed in an exhibition, but nobody knows what it is. It was part of the estate of a photographer whose father was one of the first meteorologists in Switzerland. EDIT: Adding more ...
Mat D.'s user avatar
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4 votes
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Why atmospheric temperature lapse rate doesn't have a discontinuity at 0°C when ice is formed?

When trying to calculate the adiabatic lapse rate of moist air based on known values of basic thermodynamic properties of the constituents (ice, water, vapor,...) I came to the following question: ...
MichaelW's user avatar
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1 answer
107 views

How much average temperature increase in India is due to Urbanisation and population growth?

There is an article on the BBC talking about an alarming increase of heatwaves in India. It also says that: Average temperatures in India have risen by around 0.7% between 1901 and 2018, partly due ...
FluidCode's user avatar
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2 votes
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25 views

Why is latent heat of water vapor included in specific enthalpy of moist air?

In a lecture book we read about latent heat of moist air. I would have guessed, that the total specific enthalpy of moist air, comprised of $m_d$ kg of dry air and $m_v$ kg of water vapor is (we have ...
MichaelW's user avatar
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2 votes
2 answers
83 views

Confusion with thermal wind mechanism

In meteorology, we know that cold air mass sinks while warm air mass rises due to density difference, resulting in higher pressure in cold air mass. This leads to a horizontal pressure gradient from ...
electroniclearner's user avatar
2 votes
0 answers
65 views

Altocumulus lenticularis - Why is this not considered a "strati-form type cloud

Of the major cloud families, the "cumulus" type (including stratocumulus, altocumulus and so on) are generally formed by convection in unstable air, leading to their "lumpy" or &...
James K's user avatar
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2 votes
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Correlation between cloud height and radius

Is the horizontal radius of a cloud correlated in some way with the cloud height, or are these two independent variables?
user877329's user avatar
3 votes
0 answers
55 views

Do snow gustnadoes or anything similar occur at or near the summits of the highest Himalayas such as Mt Everest?

A gustnado is a landspout (i.e. a "mini-tornado") that isn't connected to the ambient cloud base (if there is any). Mt Everest, the highest point on Earth, there is nothing "in the way&...
Giovanni's user avatar
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3 votes
0 answers
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What is a rough estimate for the number of people who have been in a tornado in their lifetime?

Discussing the relative risk of tornadoes vs earthquakes with a friend got me thinking about roughly how many people have been in tornadoes in their lifetime, which may be a statistic that would help ...
JeopardyTempest's user avatar
1 vote
0 answers
2k views

Safest place on Earth during the pole shift

Where is the safest place on Earth in relation the magnetic poles as it is moving that will provide the most protection against solar radiation? I imagine the topography may effect the magnetic fields....
Justintimeforfun's user avatar
8 votes
0 answers
59 views

Was the Earth a lot foggier millions of years ago?

Quoting a sign in Redwood National Park: Redwoods once covered large expanses of the world. Millions of years ago some of these redwoods were preserved as fossilized trees when volcanic ash buried ...
neubert's user avatar
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4 votes
1 answer
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Do I understand pressure coordinates in the right way?

The question is simple: I still have problems with atmospheric pressure coordinates: Given the pressure dependence in the picture, what are the velocity coordinates of an air parcel moving with $\vec ...
MichaelW's user avatar
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3 votes
0 answers
56 views

How is Wind oriented in a Jet Streak?

Recently I found this tutorial video about Jet streaks (want to mention I'm only in second term so my knowledge is not advanced yet). Originally I was looking for the topic because of a particular ...
MichaelW's user avatar
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1 vote
1 answer
90 views

What is 0 degree isotherm and how to calculate it?

I want to look at different areas of alpine glaciers and understand the position of 0 degree isotherm to do a comparative climate analysis. Given the mean annual air temperature and altitude, how do i ...
kc_nul's user avatar
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2 votes
1 answer
129 views

My snarky cousin tossed a monkey into my ability to see large cloud at 300 miles HELP!

The top of a cumulonimbus cloud is usually about 40,000 feet and can reach heights of over 60,000 feet, which would be visible for a distance of 245 or 300 miles, respectively. from How far away can ...
Jacques Taulard's user avatar
4 votes
1 answer
78 views

Estimating atmospheric vertical motion from 3D fields in WRF output

I have WRF data on isobaric levels that unfortunately does not contain a z-wind or omega field within the output, and I would like to produce some estimate as to the magnitude of synoptic-scale ...
Brendan Wallace's user avatar
1 vote
0 answers
15 views

How to deduce the atmospheric mixed time-space domain energy cycle formulae, and where can Arpe et al. (1986) be found?

(Where can I know) How these formulae in the figure (Ulbrich and Speth, 1991), called mixed space-time domain formulation of the energy cycle, were deduced? And the reference Arpe et al. (1986), I can ...
Swamp's user avatar
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Is it possible to calculate dew point at pressure levels from ERA5 data?

I would like to calculate dew point values at different pressure levels from the ERA5 data set. Is this possible and if so, how exactly can it be done? I have found an approximate formula that use ...
John Smith's user avatar

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