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47 votes

What does a mm of rain mean?

It's confusing to measure liquid in units of length instead of volume, isn't it? Here's how it works. "One millimeter of rain" is actually one cubic millimeter per square millimeter. On average, over ...
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20 votes

What does a mm of rain mean?

It is the amount of rain that it takes to cover the ground X milimeters deep. It is normally measured in 24 hours and is measured each morning at a fixed time like 0900. But now the measurements are ...
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17 votes

What does a mm of rain mean?

Does it mean that 3mm per square meter was experienced in a specific area, or does it mean that the total amount of rain had a volume such that if it was spread over all of Hong Kong the height ...
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17 votes

Ways to make a "How hard is it raining?" detector for personal use?

If you're open to a more mechanical solution, I'd suggest building a "tipping bucket rain gauge", best explained by a picture (source: https://www.researchgate.net/figure/Sideview-of-tipping-...
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15 votes
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Does rain (temporarily) deplete the surrounding atmosphere of carbon dioxide?

Here is the mass-calculation. We will consider a column of the atmosphere with a footprint of 1m × 1m. This column weighs about 10,000 kg (per square metre). In these days of climate change we will ...
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14 votes

Ways to make a "How hard is it raining?" detector for personal use?

Upon reading the question my first thought was, please define what is meant by "how hard is it raining?". My initial tangent thought was "what about the impact energy of the rain" -...
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13 votes

Ways to make a "How hard is it raining?" detector for personal use?

One way to do that is to estimate how much water is changing. If you can ignore the spill over, then that is approximately how much the puddle is changing. Another idea you can use is to measure the ...
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13 votes

Ways to make a "How hard is it raining?" detector for personal use?

It's not perfect, but a simple solution to the issue of a puddle building up on the resistance plate is to tilt the plate a bit, so that instead of the water building up on the plate it runs off. Your ...
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  • 231
9 votes

Can clouds be formed without a pollen particle's role?

Pollen is one of many types of cloud condensation nuclei (CCN). So can you make clouds without pollen? Yes, but you still need other sources of CC. Don’t fall into the false dilemma that pollen is a ...
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8 votes

What does a mm of rain mean?

Given any container with straight sides, 3 millimeters of rainfall will fill up that container to 3 millimeters in depth. The size of the container does not affect this. It holds whether the ...
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7 votes
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Why is thunder and lightning rare, even though it rains frequently?

Rain in a climate such as Ireland is most often stratiform. That is, it is created when moist air is lifted by a front, or by divergence in the upper troposphere. Thunderstorms involve buoyant air, ...
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6 votes

What does a mm of rain mean?

It literally means that the water depth will be 0.5mm. For example, if you place a container under the rain and it fills up to 0.5mm, then the precipitation is 0.5mm. Despite the fact that a wide ...
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6 votes

What is the significance of the "super historic" rainfall for July 2015 in southern California?

This event is "super historic" only because of its proximity to the coast. It is fairly common to get flash flooding in the mountains and deserts of Socal at least a few times each summer, due to the ...
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6 votes

Is there a consensus on the "heaviness" of rain?

If there was a worldwide standard, then WMO would have imposed it to its members. Here are the definitions in the American (NOAA/NWS) standard (summarized at NJWeatherScan, initially from manuals like ...
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6 votes

Ways to make a "How hard is it raining?" detector for personal use?

I would approach this by counting pings on a plate with an attached piezo or microphone. The amplitude of the ping will give the volume of the drop and the number of pings the drop quantity. This is a ...
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6 votes

Ways to make a "How hard is it raining?" detector for personal use?

A 'video disdrometer' is a device for characterizing raindrop size distributions. Professional versions (e.g A 1D distrometer) can use a video camera to image the shadow cast by water droplets moving ...
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6 votes
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Are halcyon days an actual phenomenon?

The story of Halcyon days is that there is a period of 7 (or 14?) days around midwinter (on the 21st of December) on which Aeolus does not make the wind to blow - to allow the Kingfisher, 'Alcyone to ...
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5 votes
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Rainbow dynamics?

Short answer: the refraction of light is ultimately dependent on both temperature and exact composition of the medium (e.g., liquid water or ice) through which it passes. Note: strictly speaking, "...
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5 votes

What is the difference between dew and rain?

Dew is condensate that forms on the surface, usually by the surface cooling to a temperature below the dew point of the air. Thus the water vapr accumulates onto the surface. Rain is formed by ...
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5 votes

Why are rain weather predictions (apparently) so unreliable still in the year 2021?

You are expecting too much. Weather forecasting has become quite reliable. There are exceptions. One exception is predicting what will happen more than seven days into the future. At ten days into the ...
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4 votes

How accurate is a tipping-bucket rain gauge?

As the previous answer made clear, tipping bucket raingauges incur errors related to tip increments, rainfall amount, intensity and duration - all for obvious reasons. Many raingauges, TB and ...
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4 votes
Accepted

How effective is seeding rainclouds? What are the indications for initiating seeding?

Cloud seeding has been attempted for well over a century, with mixed success. There is no doubt at all that, locally, rain can be increased by seeding the cloud base with such nucleating agents as dry ...
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4 votes

How to tell the difference between real rain and fake rain (cloud seeding)?

What differences exist between natural rain and human “rain”? The only physically measurable difference between rain from seeded clouds and unseeded is in the seeds/ cloud condensation nuclei/ ...
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4 votes

What does a mm of rain mean?

Simply, an "amount" of rain is a certain volume, and volume equals area x height. "3mm of rain" means for any given area, the amount of rain that fell (ie the volume) would fill that area to a height ...
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4 votes

Why do rivers sometimes travel down the opposite side of the mountains from where the rain happens?

In that image you have displayed you are assuming a 2D flow i.e. in the x and z direction where is x is the direction along the mountain range which is parallel to the ocean(or sea) and the z is the ...
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4 votes

Is pollution a contributing factor to freezing rain?

Pollution shouldn't contribute to produce freezing rain. It might have an impact in the precipitation rate and location but not on the likelihood of freezing rain. Freezing rain requires not only ...
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4 votes

Chloride ions for the salty seawater

Chlorine is a very reactive element. Contrary to your statement, chlorine occurs in many rocks and minerals. The mineral apatite, with the composition: Ca5(PO4)3(F,Cl,OH), is a natural source of ...
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4 votes
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If we could green the Sahara, would it be able to sustain itself?

The biggest detriment to keeping deserts green is of course water. With rainfall in the desert limited, afforestation is a tricky and potentially dangerous thing to do. China tried this for decades ...
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4 votes
Accepted

Is there a consensus on the "heaviness" of rain?

The German Weather Service (Deutscher Wetterdienst, DWD) provides the following definitions: Heavy rain is defined as large amounts of precipitation during a fixed period of time. [...] The DWD ...
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