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51 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 ...
jeffB's user avatar
  • 798
23 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 ...
trond hansen's user avatar
  • 1,888
19 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 ...
JeopardyTempest's user avatar
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-...
Max Klein's user avatar
  • 271
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" -...
Fred's user avatar
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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 ...
BarocliniCplusplus's user avatar
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 ...
C_Elegans's user avatar
  • 231
10 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 ...
thomasrutter's user avatar
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 ...
BarocliniCplusplus's user avatar
7 votes
Accepted

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, ...
jakewx's user avatar
  • 96
6 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/ ...
Communisty's user avatar
  • 1,064
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 ...
DanielC's user avatar
  • 171
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 ...
user2825367's user avatar
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 ...
Andy M's user avatar
  • 2,091
6 votes
Accepted

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 ...
James K's user avatar
  • 797
5 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 ...
Bohemian's user avatar
  • 243
5 votes
Accepted

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, "...
dplmmr's user avatar
  • 1,144
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 ...
BarocliniCplusplus's user avatar
5 votes
Accepted

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 ...
LazyReader's user avatar
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 ...
David Hammen's user avatar
  • 23.7k
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 ...
Camilo Rada's user avatar
  • 17.7k
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 ...
Fred's user avatar
  • 24.7k
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 ...
Erik's user avatar
  • 756
4 votes

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

I sort of accidentally did this in one of my projects in a complicated, backhanded sort of way. I installed 16 soil moisture sensors in my yard as part of an attempt to track the distribution of water ...
JRE's user avatar
  • 141
3 votes
Accepted

Is there a way to approximate the density of air during rain?

Air without rain has a mass of about $\ce{1200 g/m^3}$ at 20°C. You can figure out the amount of water in falling rain if you know the rate of accumulation (how much rain falls through a given volume ...
jeffB's user avatar
  • 798
3 votes
Accepted

What happens if it rains above the boiling point of water?

Pressure and temperature are not all the same when going up vertically. See average temperature and pressure profiles. The evaporation of any liquid has a pressure-dependent equilibrium point, see ...
AtmosphericPrisonEscape's user avatar
3 votes

Why does it rain during the sunny day?

I think Wikipedia explains quite well. It is the wind that transport the airborne water droplets from a nearby showering cloud. It is quite common in UK especially near the coast which is often very ...
Felix Leung's user avatar
3 votes

Reason for rotting smell after first rain of the season?

When rain displaces pore gasses in the soil, bubbles of soil gas are released into the atmosphere. It's impossible to be precise about the composition because it is so variable from place to place. It ...
Gordon Stanger's user avatar
3 votes

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

Weather prediction has been (https://www.ecmwf.int/en/newsletter/166/news/forecast-performance-2020) and will be getting better, but it can only get so good. Even if we build the perfect weather model ...
geodis's user avatar
  • 51

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