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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6
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0answers
78 views

Spatial variability in ocean surface winds

For the near-surface winds over the ocean, many model products and satellite footprints have spatial resolutions on the order of tens of kilometers. I'm interested in knowing how much the winds (both ...
18
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2answers
565 views

Is this ice cover real - and what circumstances are required to make it?

The title says it all... I assume it requires very slow freezing sheltered from the wind. Undercooled water, maybe? A Reddit thread talks about Delaunay triangulation, but that does not explain how ...
4
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1answer
107 views

What are the possible mechanisms that could cause a rapid drop of temperature over few days?

I live in Hong Kong. Two days ago, the average daily temperature was around 27–28 °C and in yesterday, it was around 22–23 °C (during daytime it was rather hot i.e. 26–27 °C and it was at night that ...
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0answers
76 views

NCEP reanalysis latitude and longitude represent center of cell?

I can't find any information regarding the lat and long in the NCEP Reanalysis. Do they represent the center of the cell?
2
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0answers
46 views

What determines the number of Hadley cells on a planet? [duplicate]

I know it has something to do with the rotation speed, but what exactly? And why?
5
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2answers
309 views

What kind of cloud is this?

I would like to know if anybody knows the name of this cloud formation. The picture was taken in Bern Switzerland, just before a cold front moved in. I am thinking about roll clouds or Asperatus ...
8
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1answer
625 views

How is the vertical velocity defined in sigma-pressure-coordinates?

I have a problem in deriving/understanding the vertical velocity in sigma-pressure coordinates. The vertical coordinate is defined as: $$\sigma(x,y,p)=\frac{p(x,y)-p_t}{p_s(x,y)-p_t}$$ where $p(x,y)...
3
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1answer
90 views

How to calculate hourly rainfall projections?

If the National Weather Service website shows increasing probability of precipitation (POP) over a 6 hour period (e.g. 10% rising gradually to 60%), what is the POP in this time interval if the ...
2
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2answers
112 views

Global warming and winter temperatures

What causes cold temperatures to move earlier than they usually move? Here in Buffalo the weather was 9 °C. However, everyone had winter coats and hats on. There was no snow, but it was very very ...
8
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0answers
138 views

What meteorological factors contribute to springtime Trans-Pacific air-pollution events?

The transport of tropospheric ozone, ozone precursors, carbon monoxide, etc from Asia to North America is an active area of research (see J.L. Ambrose, et al., 2011) These types of events occur ...
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0answers
77 views

practice papers for IESO [duplicate]

I am from India. Please suggest where to find practice questions for earth science Olympiad? Are papers apart from the 2010,2011 entrance test available?
9
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2answers
241 views

Does lapse rate apply below sea level?

In many parts of the world there are dry lands below sea level, such as parts of the Netherlands. Since we know that temperature decreases with increasing altitude, does it mean that temperature will ...
6
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1answer
82 views

Unusual light at sunset?

This evening in Boston there was quite a spectacular sunset. However, many people noticed this odd vertical "stripe" in the west. Has anyone seen this before? It looked as though it was projected ...
9
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3answers
373 views

Paper result validation and the scientific method in earth science

The context of this question is computational earth science specifically meteorology/climatology but I am sure it applies to all the scientific disciplines where numerical methods are used. Recently ...
8
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2answers
1k views

How accurate is a tipping-bucket rain gauge?

My question is simple - how accurate is a tipping-bucket rain gauge? I have read about what causes the errors (wind, bucket mechanics for extreme events, ...) and I know the accuracy is strictly ...
12
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1answer
332 views

Do clouds float on anything?

Clouds of the same type have such a consistent altitude, it appears as if they're floating on an invisible layer. Is this true? Put another way, is there a significant change in air composition at ...
10
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3answers
1k views

Can volcanos change the climate?

I have heard politicians claiming that volcanoes are the sole cause of global warming and using so called "NASA data" to show that the Earth is actually cooling instead of warming. While the nature ...
9
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2answers
19k views

Have two hurricanes ever merged? And what was the result?

I was just reading this about how Hurricane Ethel could have merged with Hurricane Dora in 1964. Has such a merge ever happened before in history? If so, what was the result? Would storms become ...
4
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0answers
40 views

Why did Hudson Bay melt so late this year?

The fear with the polar bears is that the ice-free period in the bay is getting longer, right? Did the consecutive polar vortex years from all this global weirding make the bay's winters colder? It ...
4
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1answer
238 views

Why is it always rainy in Addis Ababa?

I watch the news and in the weather forecast it's always rainy in central Africa, especially in Addis Ababa. Why is that?
3
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1answer
72 views

Is it possible to have a busier tropical storm season in the eastern Pacific basin than in the western Pacific basin?

It is known that hurricane activity in Atlantic basin is less active than in East Pacific basin in seasons past, but for the 2005 and 2010 seasons, the Atlantic basin is busier than western Pacific ...
11
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3answers
511 views

Is increase in atmospheric $\mathrm{CO}_2$ concentration affecting Earth's atmospheric pressure?

It's well known that the $\mathrm{CO}_2$ levels around the world are increasing, leading to an increase in overall surface temperature, etc. But I'm wondering, are these gases (or the effects from ...
12
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2answers
2k views

Can an Atlantic hurricane enter Mediterranean sea?

I can't find any examples, has it just never happened before or is it impossible because of environmental factors?
9
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1answer
687 views

Why are there different vertical gradients of temperature in different layers of the atmosphere?

The temperature of the troposphere decreases with altitude whereas it is opposite in the stratosphere and again fluctuates. Why is this so?
6
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2answers
2k views

How to plot lat-lon-rainfall in MATLAB?

I have average annual rainfall values at few grids, as shown in below example; Lat: 25.5 26.5 33.5 34.5 35.5 36.5 41.5 42.5 Lon: 89.5 91.5 78.5 79.5 83.5 84.5 75.5 76.5 Rain: 110 120 122 135 114 ...
8
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2answers
608 views

How to perform regridding (1.0d to 0.5d) using bilinear interpolation for an irregular area?

I need to regrid temperature dataset from 1 degree to 0.5 degree. In case we have data available for all grids falling in a square, as shown below, we can simply regrid it using bilinear/bicubic ...
7
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2answers
565 views

Dew point variation in a day

Is this true? "If there are no weather front or severe weather systems, then the dew point within a single day is fairly constant, no matter how large the day/night temperature variation."
11
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3answers
323 views

Wind profile below the aerodynamic roughness length

The vertical profile of horizontal windspeed is often given by the so-called "log-law": $$u(z)=(u^*/k)\ln(z/z_0),\ \mathrm{for}\ z>z_0,$$ which can be found here. As can be seen from the ...
4
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0answers
595 views

Explanation of yellow/pinkish sky? [closed]

Last night the sky suddenly went yellow/pinkish colour. It looked like someone placed a transparent yellow/red plastic over our windows. I went outside and everything looked a pink/yellow colour, ...
10
votes
1answer
22k views

Why does it rain more at night than during the day?

I'm living near a sea, and it rains mostly and heavily at night from 11 PM to 3 AM. The weather is mostly clear during daytime. Air is generally cooler at night, and cool air holds less moisture ...
9
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0answers
132 views

Is there a distinction between gap winds and channelled flow?

I have seen gap flows mentioned in the literature, for example [Gohm et al. 2004, Zängl 2002, Mayr et al. 2007]. Whiteman 2000 defines a gap as a "major erosional opening through mountain ranges" and ...
9
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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 ...
10
votes
1answer
463 views

Explanation for growing circular echo on weather radar?

Does anybody have an explanation for the growing ring/growing circular echo that I occasionally see on weather radar? Attached is a gif of a NEXRAD loop showing areas around Denver, CO, Aug. 2, 2015 3:...
10
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1answer
887 views

How does evapotranspiration affect rainfall?

Evapotranspiration is when a plant evaporates water off the surface of its leaves in order to move water throughout its system with cohesive and adheisiveforces. My question is how will a sudden ...
15
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3answers
11k views

How far away can you see a thunderstorm?

At 9:30 PM on July 13, 2015, I was looking due south from Oshkosh, WI. I saw very clearly a large storm with 1-2 lightning strikes per second. I could see cloud-to-cloud lightning traces, as well as ...
11
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1answer
238 views

How are low pressure zones tracked across the ocean?

When you look at a surface pressure chart e.g.: (from http://www.metoffice.gov.uk/public/weather/surface-pressure/#?tab=surfacePressureColour&fcTime=1437480000) you can see low pressure zones ...
8
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1answer
369 views

What is this cloud formation?

What is the cloud formation in this video? I don't know where this footage was taken. Here's the link to the video again.
10
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1answer
403 views

Optimal vertical coordinate for complex topography

There are plenty of choices in models in so far as choice of vertical coordinate is concerned for meteorological models. Five that I know of: The sigma coordinate system - Hybrid coordinate system(...
10
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2answers
212 views

How do the various types of clouds affect the atmosphere below them in a polluted environment?

I am working through this problem on my own as well, but am feeling that some perspective is in order. So, ignoring the obvious effects where precipitation will wash stuff out of the air, and blocking ...
10
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2answers
341 views

The origin of spurious high frequency waves in numerical weather prediction

I am currently reading this paper on digital filters and their relevance to meteorological models Digital Filter Initialization . My question relates to this following text - "The requirement to ...
21
votes
2answers
3k views

Is there an upper bound to the amount of rain that can fall in an hour?

The record for most rainfall in a single hour is 12 inches (30.5 cm), set in Holt, Missouri, in 1947. What is the maximum amount of rainfall that could theoretically occur in an hour?
7
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2answers
250 views

Are Southern Hemisphere 'Polar Blasts' caused by global warming?

The SMH journalist writes about a cold snap hitting the East Coast of Australia in July 2015: Proof of the big chill will be the extent of regions across Tasmania, Victoria and NSW experiencing ...
6
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3answers
15k views

What is a temperature inversion and can it trap smog/pollution?

Just as the title says, I heard about this term but am not sure how it works.
4
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1answer
77 views

How can I define frost based on a weather record?

If I want to (programatically, in a plant growth model) define a growing season as last frost in spring to first frost in fall, how might I determine these dates based on a weather record that ...
7
votes
3answers
434 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 ...
8
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1answer
14k 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)....
9
votes
1answer
823 views

Evaporation loss formulas

A while ago I created a spreadsheet to calculate evaporation loss. I found several formulas to do that, two from Kevin Rafferty and one from Engineering Toolbox. The one from Engineering Toolbox was ...
3
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2answers
106 views

Why do clouds have areas of darkness instead of scattering light to produce a rainbow?

I suspect it has to do with the difference in size of a rain drop and that of the water particles in the cloud.
6
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1answer
802 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. ...
4
votes
1answer
2k views

How do I convert Relative Humidity into specific humidity [duplicate]

I am using NCEP_DOE reanalysis 2 data set. It include only relative humidity while I need specific humidity. How do I convert the relative humidity into specific humidity?