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45

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 the area you're talking about, each square millimeter has received one cubic millimeter of rain. If you divide n mm3 by 1 mm2, you get -- n mm! The field of ...


18

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 fully automatic, so the meteorological service gets the data more often and can provide data for each hour of the day. Total rainfall is still measured from ...


17

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 would be 3mm. Or is it referred to in terms of per square meter? They're really the same idea. Fundamentally it means that it filled a rain gauge (of some ...


16

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-bucket-Rain-Gauge_fig4_304297354): This should be relatively easy to build and it's trivial to read this electronically by detecting the time it takes to tip. ...


14

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 assume the current average CO2 concentration is 400 ppm, yielding a total mass of CO2 in this column of 4 kg. The rain doesn't wash out the entire thickness of ...


13

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" - heavy rain can be felt. Anyone who has heard rain fall on a metal or poly-carbonate roof will know the difference in noise produced by light and heavy rain. ...


12

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 changing weight of a rain gauge (that will need to be emptied daily, unless you can rig something that will do that for you). The faster the weight increases, ...


12

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 device would then look for sudden drops in resistance, indicating that a droplet has formed on the device, followed by the resistance rising again after the ...


9

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 requirement for cloud formation. The more soluble the CCN is, the easier it is to form a cloud (see Koehler theory). Can a cloud be formed without CCN? I saw it ...


8

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 container is the size of a tennis court, or the size of a small beaker or a test tube with a flat bottom. As long as its sides are vertical and uniform. It is also ...


7

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, which rises on its own due to its being warmer than its surroundings. Typically solar radiation is involved in heating the surface such that the air near it warms ...


6

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 container requires more rain to fill up than a narrow container, the larger surface area allows it to collect the right amount of rain water to fill up to the same ...


6

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 Southwest Monsoon. This event was different in that a dying tropical system moving north off of the coast of Mexico interacted with a trough off of the ...


5

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, "steam" typically refers to water vapor at temperatures above the boiling point, but in casual usage (and for the purposes of this answer) it is commonly used to ...


5

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 Collision-Coalescence or the Bergeron-Findelsen process. The cloud droplets are formed by the condensation of water vapor on aerosols, when the air reaches ...


5

If there was a worldwide standard, then WMO would have imposed it to its members. Here are the definitions in the American (NOOA/NWS) standard: http://www.njweatherscan.com/definitions_of_precipitation.htm Light rain: falling rate of less than 2,54 mm/h. Moderate rain: falling rate of more than 2,8 mm/h, but less than 7.6 mm/h. Heavy rain: fallin rate of ...


5

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 more robust real-world interface than an electrode sensor.


5

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 in front of a bright light. So one DIY approach might be a camera imaging rain drops falling through a gap. Delft university have put up an instructable for an ...


4

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 otherwise, have funnel filters to stop clogging from leaves, dead lizards, etc. In the case of small rainfall events the wetting and clogging of the filter can cause ...


4

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 ice or silver iodide smoke. There is a great deal of doubt as to whether there is any overall gain in rainfall - or is it just an expensive way of 'robbing ...


4

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/ aerosols that are the surface that moisture can condensate onto and form cloud droplets. Measurements You could collect rainwater, evaporate it and the remaining ...


4

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 of 3mm. The area part of the formula is effectively a constant. The only variable is the height.


4

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 vertical direction. This is a very simplistic assumption of mountain topography as depending on the context one can have mountain gaps and then the moisture ...


4

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 that the near-surface temperature is below freezing, but also that there is a temperature inversion that provides above zero temperature in the atmospheric layers ...


4

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 chlorine. Virtually all rocks contain chlorine. Chlorine even occurs occurs in alkaline magmas. One of the most common minerals containing chlorine is common ...


4

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 future, forecasts remain pretty much a random guess. The 1960s discovery that weather is chaotic (Predictability: Does the flap of a butterfly's wings in ...


4

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 issues warnings of heavy rain using three categories: heavy rain: 15 to 25 l/m² within 1 hour or 20 to 35 l/m² within 6 hours severly heavy rain: 25 to 40 l/m² ...


4

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 in the soil of a flower garden. The sensors are battery powered. They transmit their data via Bluetooth Low Energy to a couple of WiFi enabled control nodes in ...


3

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 the phase diagram of water and Clausius-Clapeyron for a mathematical description of the equilibrium point. However, I assume that you mean with 212°F (100°C) ...


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