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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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What is brown carbon?

There is a lot of interest in brown carbon in the atmospheric science community these days. There is a paper in the journal, "Atmospheric Chemistry and Physics" titled, "Black carbon or brown carbon? ...
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2answers
31 views

Can I interpolate rainfall data from stations outside of watershed for the watershed?

I have only few station inside the watershed so I want to use the stations outside if I can to get better results
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0answers
24 views

I found this small round heavy rock in a box of my dad’s old army stuff [on hold]

I found this seavy black silvery rock found in a box of my dad’s old army stuff. He was stationed in Arizona sometime in the 50’s. Not sure if it’s from there or just happened to be in that box.
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0answers
43 views

Initiation of Rossby waves during MJO

I am trying to understand the basic dynamics of MJO, where I find several studies which relate it to the initiation of equatorial Rossby and Kelvin waves. Though MJO is an eastward propagating wave, I ...
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1answer
89 views

Why is potential vorticity so emphasized in technical work, but often neglected in maps on weather websites?

When I was first introduced to potential vorticity, I was told that it is a very important tool for meteorologists to learn. Sure, it solved a simple problem in dynamics, but it wasn't apparent to me ...
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0answers
37 views

Characteristics of saddle points in stream line charts

I am trying to locate saddle points or commonly known as "col" in synoptic meteorology. This is "z" in the following figure. References Here are some of the references regarding this. a). http://www....
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0answers
25 views

What exactly are “ambient aerosols”?

I see this term being used everywhere, but I have not been able to find a formal definition for "ambient aerosols".
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1answer
44 views

Locating shearlines or deformation zones in a map

I am looking for a way to detect shearlines or confluence regions such as that shown in the figure below (red dashed line). I was able to derive the stretching, shear, and total deformations. The ...
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1answer
5k views

What do quasi-geostrophic and ageostrophic mean?

I know that geostrophic flow means straight wind flow that is balanced by the pressure gradient and Coriolis forces. But what do quasi-geostrophic and ageostrophic mean specifically?
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1answer
56 views

How big of an event is needed to trigger a long winter?

Could a small meteor or natural nuclear explosion melt an ice cap on Earth to trigger a mini ice age without the event being observed by people? Can the Earth have an overlaying thermal cycle that ...
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12 views

Moisture flux convergence/divergence calculation in Grads

I want to calculate moisture flux divergence/convergence in 850 hpa for the summer and I have monthly mean gridded data sdfopen shum.mon.mean.nc sdfopen uwind.mon.mean.nc sdfopen vwind.mon.mean.nc ...
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1answer
108 views

Are these plane trails seen from satellite

Here are photos from West of Normandy, at 7-9am after sunrise on the 14th of may, from the visible satellite. It's a bit strange that they are visible from space, they are 2-3 miles wide? Are they jet ...
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69 views

Does this weather pattern have a name?

The past few weeks of spring in northern Ohio I believe I have noticed a weather pattern where the weather forecast will show a string of days with rain, but what happens is the day is mostly clear, ...
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38 views

Which are the greatest disadvantages of this description of glaciation periods?

At the beginning of a global cooling and a new glaciation there is a lot of snow covering more land areas in north longer and longer times, until the last season's snow remain into the new season. The ...
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1answer
36 views

Decomposition of variables in horizontal and vertical modes

I have a query regarding the practical applicability of variable separable method. Usually we decompose the variables w.r.t components corresponding to different dimensions, this method is used to ...
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3answers
366 views

Algorithmically Determining the Rainy Season

I have historical precipitation data for hundreds of cities around the world. I would like to algorithmically determine when the rainy season (if exists) is for each location. Are there any algorithms ...
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1answer
29 views

Get atmospheric pressure values through JavaScript

I'm working on a programming project in which I want to show isobars on a map with OpenStreetMap and the HTML tag canvas. The main problem that I'm facing is the dificulty of retrieving consistent ...
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1answer
92 views

How to improve this prediction about the climate in future?

The more carbon dioxide in the atmosphere the more global warming. The more global warming the more cloud formations that cool the earth and clean the air from carbon dioxid when rain- and snowfall, ...
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2answers
239 views

Extracting Regional Data from ERA5

This is coming from a newcomer, so please be kind. As I delve into the world of meteo data and reanalysis for the first time, I found that acquiring weather data is a lengthy process, so I'm shouting ...
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43 views

Can extratropical cyclones force global cooling?

We are living in a historical period of global warming since about 20,000 years ago. This global warming period is one of about ten in human history. Those periods may very well be forced to start by ...
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1answer
143 views

What kind of climate could you expect in a mountainous area in a subtropical region?

More specifically, I'm trying to work out climate analogues for my farm. It's at 5200-6200ft in South India. My area is a bit too small for the Köppen Map to correctly reveal patterns. I'll be ...
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0answers
71 views

Atmospheric pressure in weather forecasts: actual pressure or sea-level pressure [duplicate]

What is the usual way to report surface pressure in weather forecasts online, in smartphone apps, on TV/radio? Is it the actual local pressure or the sea-level adjusted value? Does it differ by ...
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2answers
850 views

From where do weather radar maps get their data?

I see maps like this one all the time online and in the news. A moving map that shows clouds and stuff moving around with time. Where do they get the data from? Is it from a single source location or ...
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2answers
404 views

Centrifugal Force in the Navier Stokes Equations

The Navier-Stokes equations are a set of nonlinear differential equations that diagnose wind speed and direction. They are (approximately) expressed as $$\frac{d\vec{u}}{dt}=-\frac{1}{\rho}\nabla P+f\...
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1answer
57 views

Computation of geostrophic wind

I am attempting to calculate the zonal and meridional components of geostrophic wind using the equations below: $u_g = -\frac{g_0}{f} \cdot \frac{1}{r} \cdot \frac{\partial \Phi }{\partial \phi}$ $...
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2answers
12k views

Why are deserts mostly located on the western side of continents?

I read somewhere in a book that mostly desert found in the western part of a continent. So my question is that why is it so? I searched on the internet but I didn't get a reasonable answer for that.
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41 views

Ordered arrangement of clouds

I happened to take a photograph of a region of clouds ,and it seems to have a rather ordered arrangement ,if one looks towards the left of the image. Would there be a physical explanation for this or ...
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0answers
68 views

Using salinity to predict rainfall

Recently, a new method has been proposed by Ray Schmitt (WHOI) and collaborators to use salinity patterns in the ocean to predict weather events (more specifically, rainfall) at scales from weeks to ...
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2answers
112 views

Is pollution a contributing factor to freezing rain?

I have been to different places with nearly the same freezing temperatures, around -2°C, but only at some specific places I repetitively experienced freezing rain. One common factor at these places ...
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0answers
86 views

Modification of an air mass

If an air mass that exists in North America starts moving south west or south east what kind of modification will affect it and how would you characterize it in it's final state? My answer is that it ...
2
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1answer
144 views

What are these Gizmos at Mauna Loa Observatory?

Artist Rosten Wu's Vimeo channel has a video title Bridging Time and there is discussion about the Keeling Curve and the site where it all began in Hawaii. In the video there is a shot of a weather ...
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5answers
5k views

Is it true that a butterfly flapping its wings can result in a tornado in a distant location?

I have heard that extreme storm events can be caused simply by a butterfly flapping its wings somewhere in a distant location. Is it true that such a small disturbance in the air in one location can ...
19
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1answer
971 views

Why is there no middle ground between tornadoes and hurricanes?

A tornado has an effective area of destruction about the size of a city block. A hurricane spans several hundred kilometers. However, there doesn't seem to be a continuum between the two. Why are ...
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6answers
14k views

Why doesn't the 71% water of the earth dry or evaporate?

Perhaps a simple question, we know 71% of the earth's surface contains water as oceans. If Earth's age is 4.543 billion years, then I guess it should be decreased with drying or should have been dried ...
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0answers
374 views

Is it possible for a sting jet to form over a continental landmass?

Sting jets are thought to be responsible for some of the most damaging winds associated with extratropical cyclones in the mid-latitudes. So far they have only been confirmed in the European region, ...
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2answers
2k views

What is the steepest surface that can hold snow?

I know it depends on the type of snow (dry or wet) and the rougness of the surface. I'm looking for an approximate rule of thumb answer. Assuming a reasonably smooth surface, at what angle it's likely ...
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3answers
3k views

What causes clouds to appear blue?

In a thunderstorm cloud about sunset time, I saw these clouds, including some (in the upper right) that were a unique shade of blue. I don't think I've seen clouds quite that color before. I tried ...
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2answers
423 views

What are these Gizmos at Izaña Atmospheric Research Center in Spain?

This tweet from the account of the Centro de Investigación Atmosférica de Izaña (AEMET) http://izana.aemet.es Izaña Atmospheric Research Center (AEMET) shows images of meteorological instruments ...
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0answers
77 views

How to plot orography for vertical profile of a certain variable along pressure levels in GRADS

I am using GRADS (1, 2, 3) to plot ERA reanalysis relative humidity profile for latitudinal average of 15N to 37N, and along the longitude from 40E to 130E. The orography is quite obvious and thus ...
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1answer
2k views

Why does wind blow offshore in the morning?

I live in San Diego, CA, and surfers capitalize on dawn hours because the offshore (seaward) winds help "hold up" the waves, i.e. prevent them from crashing before the surfer gets to ride it a while. ...
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2answers
645 views

What was the density and composition of Earth's atmosphere during the Cretaceous warmest period?

There was time during the age of dinosaurs when the polar regions were ice free. The earth was obviously much warmer but a run-away greenhouse effect did not occur. This was most likely because the ...
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1answer
189 views

Madden-Julian Oscillation (MJO) - How to interpret the index?

How the Madden-Julian Oscillation (MJO) index can be interpret? Let's suppose I have got an MJO index value of 0.6 in a given day, what this does mean? Does 0.6 represents a weak MJO? Data from ...
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1answer
78 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 ...
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2answers
143 views

Did temperature for the US state of Illinois reach an all-time record low 1/31/2019?

The State Climatologist Office for Illinois says the all time low temperature of Illinois was -36 °F, with a report of -37 °F in 2009 being disqualified. This morning, the station Sinnissippi ...
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1answer
493 views

Two severe cyclones connected by a monsoonal trough

At the time of writing, areas around the Northern Territory (TC Lam) and Queensland (TC Marcia) in Australia are in the path of severe cyclones (category 4 at the moment, with the Queensland one - TC ...
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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 ...
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1answer
158 views

How can temperature be calculated given relative humidity and dew point?

While looking into the better indicator of how miserable it feels outside, either dew point or relative humidity, I came across this statement: The optimum combination for human comfort is a ...
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35 views

Just how dry could Ben Nevis get? Is this surprising?

The BBC article Soggy Ben Nevis can be remarkably dry describes results of a crowdscience effort to transcribe historical meteorological records recorded manually by researchers living on top of "Ben ...
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2answers
4k 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 ...
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0answers
60 views

Roughly what proportion of a cloud does 'rain out'?

What proportion of the water in a cloud will 'rain out'? Or, comparing the cloud before and after it has rained, what proportion of the water is left afterwards? I really have no idea so am just ...