Cold Air Rises – How Wrong Are Our Global Climate Models?

Some nonsense about humid air (clouds) from Scientific American:
https://de.quora.com/Why-do-clouds-float
https://www.scientificamerican.com/article/why-do-clouds-float-when/
Some Nonsense from Scientific American
https://www.scientificamerican.c…
Why do clouds float when they have tons of water in them?
Douglas Wesley, a senior meteorologist in the Cooperative Program for Operational Meteorology, Education and Training (COMET) at the University Corporation for Atmospheric Research, explains:
Image: RON HOLLE, University of Illinois Cloud Catalogue
FLOATING CLOUDS.The water and ice particles in the clouds we see are simply too small to feel the effects of gravity. As a result, clouds appear to float on air.
Clouds are composed primarily of small water droplets and, if it’s cold enough, ice crystals. The vast majority of clouds you see contain droplets and/or crystals that are too small to have any appreciable fall velocity. So the particles continue to float with the surrounding air. For an analogy closer to the ground, think of tiny dust particles that, when viewed against a shaft of sunlight, appear to float in the air.
Indeed, the distance from the center of a typical water droplet to its edge–its radius–ranges from a few microns (thousandths of a millimeter) to a few tens of microns (ice crystals are often a bit larger). And the speed with which any object falls is related to its mass and surface area–which is why a feather falls more slowly than a pebble of the same weight. For particles that are roughly spherical, mass is proportional to the radius cubed (r3); the downward-facing surface area of such a particle is proportional to the radius squared (r2). Thus, as a tiny water droplet grows, its mass becomes more important than its shape and the droplet falls faster. Even a large droplet having a radius of 100 microns has a fall velocity of only about 27 centimeters per second (cm/s). And because ice crystals have more irregular shapes, their fall velocities are relatively smaller.
Upward vertical motions, or updrafts, in the atmosphere also contribute to the floating appearance of clouds by offsetting the small fall velocities of their constituent particles. Clouds generally form, survive and grow in air that is moving upward. Rising air expands as the pressure on it decreases, and that expansion into thinner, high-altitude air causes cooling. Enough cooling eventually makes water vapor condense, which contributes to the survival and growth of the clouds. Stratiform clouds (those producing steady rain) typically form in an environment with widespread but weak upward motion (say, a few cm/s); convective clouds (those causing showers and thunderstorms) are associated with updrafts that exceed a few meters per second. In both cases, though, the atmospheric ascent is sufficient to negate the small fall velocities of cloud particles.
Another way to illustrate the relative lightness of clouds is to compare the total mass of a cloud to the mass of the air in which it resides. Consider a hypothetical but typical small cloud at an altitude of 10,000 feet, comprising one cubic kilometer and having a liquid water content of 1.0 gram per cubic meter. The total mass of the cloud particles is about 1 million kilograms, which is roughly equivalent to the weight of 500 automobiles. But the total mass of the air in that same cubic kilometer is about 1 billion kilograms–1,000 times heavier than the liquid!
So, even though typical clouds do contain a lot of water, this water is spread out for miles in the form of tiny water droplets or crystals, which are so small that the effect of gravity on them is negligible. Thus, from our vantage on the ground, clouds seem to float in the sky.
Answer originally posted May 31, 1999
My comment:
The nonsense:
1. For an analogy closer to the ground, think of tiny dust particles that, when viewed against a shaft of sunlight, appear to float in the air.
2. The water and ice particles in the clouds we see are simply too small to feel the effects of gravity.
3. The total mass of the cloud particles is about 1 million kilograms, which is roughly equivalent to the weight of 500 automobiles. But the total mass of the air in that same cubic kilometer is about 1 billion kilograms–1,000 times heavier than the liquid!
Ad 1.:
Dust particles in a house are moved by very small currents created by even very small temperature differences.
Ad 2.:
Any mass “experiences” gravity! Even molecules settle. The concentration of higher weight molecules – e.g. CO2 – is higher at the ground.
Ad 3.:
This calculation is only silly! The weight of a cloud is a high as the adjacent volume of air at the same pressure and temperature. Clouds never stay constant. They vanish if no energy is added (velocity or temperature).
In addition:
Even though I am not an expert in “Relativity Theory”, I learned from Einstein that even photons are experiencing gravity (zero mass but energy – equivalence of mass and energy).
Obviously even well recognized meteorologists and the editorial board of Scientific American do not now the basic fact, that humid air has a lower density compared to dry air. https://www.vaisala.com/de/lp/hu…
The above copied article showed up first when asking Google: why do clouds float?
Example for humidity calculations
Relative humidity/% Temperature/°C Pressure/hPa Density/kg/m^3 Water/g/Nm^3
0 20 1013.3 1.2041 0
100 20 1013.3 1.1936 18.609
Above calculations from the author use a water content of only 1g/m^3.
The density difference is 0.8796%. This looks very small. But these humidity differences – besides temperature differences – are driving the weather.
A rising cloud has a lower density compared to adjacent air. A raining cloud is heavier and a momentarily stagnant cloud has the same density.
Clouds are never permanent!