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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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142 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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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?
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2answers
258 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 ...
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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 ...
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3answers
384 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 ...
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2answers
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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 ...
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1answer
342 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 ...
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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 ...
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2answers
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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 ...
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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 ...
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1answer
253 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?
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1answer
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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 ...
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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 ...
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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?
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710 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?
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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 ...
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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 ...
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2answers
600 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."
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3answers
335 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 ...
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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, ...
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1answer
24k 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 ...
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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 ...
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3answers
4k 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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1answer
519 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:...
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1answer
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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 ...
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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 ...
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1answer
265 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 ...
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1answer
374 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.
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1answer
412 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(...
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213 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 ...
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350 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 ...
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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?
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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 ...
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3answers
16k 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.
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1answer
79 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 ...
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3answers
479 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
15k 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)....
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1answer
848 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 ...
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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.
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1answer
831 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. ...
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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?
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2answers
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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 >...
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2answers
1k views

Why are clouds darker before it rains?

What causes the darker color of the clouds (nimbus) when it is about to rain? Non-precipitating clouds (e.g., cumulus, stratus) tend to be white, but rain clouds become gray and almost black before it ...
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2answers
3k views

Why do clouds sometimes form a ring around the Sun?

Someone shared a video with me in which clouds were forming a ring around the Sun. I took this screen shot of that video: What is the reason behind this?
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1answer
365 views

What is “focus point” in WRF-plots grid box? (python code)

has anyone used the python code from here (written by Geir Arne Waagbo) to plot skewT plot from WRF output? I've got a question regarding some of the functions used in the code found in ...
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3answers
7k 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 ...
6
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1answer
185 views

Eliminating range folding error in doppler radar returns

With weather radar, it's not uncommon to see large areas of the image blocked out due to detected range folding. It's my understanding that this occurs when a reflection outside of range comes back ...
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2answers
4k views

Why do certain areas on Earth have a higher or lower air pressure at sea level?

For instance, looking at this map of world air pressure in January and this map of July, why do some land surfaces have a higher pressure during the winter? I know that the tropics and Coriolis ...
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2answers
756 views

How can daily brightness be quantified or measured?

It occurred to me that there might very will be a metric out there that measures and quantifies "daily brightness". Meaning, how bright any given day is, taking weather conditions and cloud coverage ...
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2answers
3k views

Are lightning storms more common at night?

I have, to my knowledge, seen far more lightning strikes and heard more thunderclaps at night than I have during the day. Are lightning storms more common at night, or are they just more noticeable ...