# Tag Info

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 ...

13

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 ...

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 ...

8

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 ...

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

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 ...

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 ...

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) ...

3

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 windy. Usually the weather forecast will say that it has scattered shower with sunny spell. https://en.wikipedia.org/wiki/Sunshower

3

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 varies according to soil type, organic content, degree of rotting, temperature, and the microbiological cross section (itself hugely variable). Most soil gas ...

3

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 in a given time, landing on the ground) and the velocity of the falling rain. Here's a link to a post elsewhere on this same question. In that discussion, ...

3

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 with afforestation efforts, planting billions of trees in steppe regions of China and Mongolia, only to later worsen because the trees consumed too much ground ...

2

Mango showers, or ‘mango rains’, is a colloquial term to describe the occurrence of pre-monsoon rainfall! Monsoon is prevailing wind due to seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern. They ...

2

Rain is slightly cooler than near-surface temperatures because it condenses at higher altitudes where the air is colder. Thus rain tends to reduce the temperature difference between the surface and higher altitudes. This temperature difference is the free-energy or exergy source that ultimately drives convective weather systems and storms, and is expended or ...

2

Climate normals are computed over 30 years. Not sure why that number of years was chosen specifically. Perhaps a recent incentive is to identify climate changes (though it actually would make warming appear less significant when looking at anomalies). But, given that those trends have only gotten interest in the past few decades, the only historical ...

2

It will depend on how the temperature and humidity change as the raindrops approach the bottom of the column. If the air is hot and dry, the drops will evaporate. If it's hot and humid enough, they may survive to hit the bottom. Remember that the boiling point of water rises as pressure increases! Your statement "If it rains at a temperature lower than [32 ...

2

Both are condensation, but dew forms directly on a solid surface, rain forms in the air. In theory you could form dew in any part of the atmosphere if you had something for it to form on.

2

I think what you mean by thermo-electric nitrogen fixation is the nitric oxides created by lightning discharges. This is absorbed by the raindrops as they form and as they fall to earth, and helps to fertilise the soil. You won't get this effect with sprinkler irrigation to any great extent, because the water droplets are exposed to the nitrogen oxides for ...

2

Flood control measures largely depend on: The amount of money available to create flood control measures The availability of raw materials that could be used to create such measures The locality of the potentially flood affected region The source of potential flooding and its relation to the region that could be flooded. One extreme example is Bangladesh. ...

Only top voted, non community-wiki answers of a minimum length are eligible