Multiple Cloud Layers
Hi, Last week I was flying out of DC, and I counted 7
distinct and broad layers of clouds. How can this be? My
understanding is that there are 2 major cloud formation mechanisms
(Convective and Stratiform) which can occur separately or at the
same time, but I do not understand how these two methods can give
rise to 7 layers of clouds in the same altitude profile. Can there
really be such a complex pressure profile in the atmosphere over the
same height profile? Could you please refer me to other sources so
that I can read up on these weather effects?
Your question is similar to one that I answered on the topic
"Cloud Layers" for Jean C. You can find that answer
in the Ask-A-Scientist database under "Cloud Layers".
However, you have seen an unusual number of cloud layers
occurring at one time.
This is an indication of several layers of air where a low
enough temperature is reached at the top of the layer to bring
the air to the dew point (saturation of the air to produce clouds).
This can sometimes be caused by multiple daily inversion layers
being built up, one on top of another as the inversion from the
previous day is isolated and lifted higher each day. Another
possibility is that there was a complex frontal system in the area,
such as a cold front plus an occluded front in association with a
low pressure area; the stacked layers of air flowing over and
under each other in such a complex system can create multiple
David R. Cook
Climate Research Section
Environmental Science Division
Argonne National Laboratory
Water has three phases depending on pressure and temperature.
As a gas: Steam vapor
As a liquid: Water
As a solid: Ice
Clouds are either water or ice particles.
Each phase of water has its own density.
Density is the mass per unit volume of a substance.
Steam vapor has the least density.
Water has higher density (usually serves as the standard and is set to 1.0)
Ice has an even higher density.
Clouds of water or ice will rise to a level where their density is equal to
the density of that particular layer of air at that particular altitude.
The seven layers you saw mark seven different density layers in the air
column where the clouds are formed.
Ideally, the temperature goes down linearly as altitude increases, but more
often than not there are layers of temperature inversion, where the
temperature starts getting warmer as altitude increases, at least for a
So it is quite possible to have several layers of water and ice clouds at
several different altitudes in the atmosphere.
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Update: June 2012