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Author Topic: Cloud top height  (Read 10733 times)

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Offline administrator

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Cloud top height
« on: January 28, 2012, 09:49:03 AM »
There's a formula that allows the height of the cloud base to be estimated, but does anyone know of a formula that allows the height of the cloud top to be estimated? I'm thinking in terms of using pressure/temp/etc values and not trigonometric type formulas for working out the height based on angles/distances.
Chris
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Offline jmcmurry

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Re: Cloud top height
« Reply #1 on: January 28, 2012, 10:40:59 AM »
Chris,

I don't know if this will help, but in searching I found the formula in http://www.brockmann-consult.de/CloudStructures/introduction.htm to show up on a couple sites.  Maybe a piece of the puzzle, maybe not.

h [km] = -8 * LOGS (cloud_top_press [hPa]/1013)

So now, where do you get cloud_top_press?

- Jim

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Re: Cloud top height
« Reply #2 on: January 28, 2012, 12:23:25 PM »
Thanks for the useful pointer Jim. I think I have a source for the pressure at the cloud top so I'll have to experiment and see if it gives me sensible values.
Chris
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Offline jmcmurry

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Re: Cloud top height
« Reply #3 on: January 28, 2012, 01:14:14 PM »
Great!  I'd be interested in seeing how that works out, in fact if it does, it could contribute to one of my scripts.

- Jim

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Offline NorCal Dan

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Re: Cloud top height
« Reply #4 on: January 28, 2012, 04:15:07 PM »
Now you have me wondering what causes clouds to stop at a certain altitude?

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Re: Cloud top height
« Reply #5 on: January 28, 2012, 05:29:16 PM »
Now you have me wondering what causes clouds to stop at a certain altitude?

The same things that make them appear at certain altitudes?
Chris
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Re: Cloud top height
« Reply #6 on: January 30, 2012, 11:11:43 PM »
Quote
Now you have me wondering what causes clouds to stop at a certain altitude?

if you are not meaning a CB hitting the troposhere (where the temperature starts to get warmer again)
and instead are refering to mid height clouds
then the answer is inversion layers (i.e it hits a layer of air above that is warmer)
often called capping
if the heating is strong enough then it can break through this cap

often anticyclones have inversion layers, i.e colder air trapped underneath the warming sinking air

Offline embayweather

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Re: Cloud top height
« Reply #7 on: February 01, 2012, 03:02:14 PM »
Worth looking at Radiosonde plots to get a better understanding of cloud structure, base and tops. I found trying the RAOB demonstration program at
http://www.raob.com/, worth trying too. Even if you never buy the program itself there are a lot of things you can learn from it. The though looks amazing program looks amazing and does just what it says on the tin and more. I am hoping to buy it this year.

Best wishes

Mike

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Re: Cloud top height
« Reply #8 on: April 12, 2012, 07:54:54 AM »
Hi..
I am postgraduate student and I am doing research on meteorology by using remote sensing technique. Is there have any formula to estimated cloud top pressure besides using Ideal gases law?

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Re: Cloud top height
« Reply #9 on: September 20, 2015, 08:52:00 PM »
There is no formula for cloud top height.  You must first identify the height (or pressure) of the Base of the cloud, then work upwards until the Relative Humidity (RH) decreases to your pre-determined threshold, where it becomes too dry to support cloud formation.
John Shewchuk

Offline sv1aaw

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Re: Cloud top height
« Reply #10 on: December 21, 2015, 08:15:50 PM »
The cloud base is from the temparature the dew point and humidity for this reason they are very special in the airports METAR.
You can calculate the cloud base and the cloud top height (where they stops) very important in VFR condition fly. There is and an recent accident with airplane (UL) in Italy
73 de
SV1AAW

Offline niko

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Re: Cloud top height
« Reply #11 on: December 21, 2015, 08:35:12 PM »
You can calculate the cloud base and the cloud top height (where they stops) very important in VFR condition fly.

What's the formula/calculation for cloud top height?

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Re: Cloud top height
« Reply #12 on: December 21, 2015, 10:47:08 PM »
Asking for a formula to find Cloud Height is like asking for the location of the Fountain of Youth.  It does not exist.  However, after working on the RAOB program for over 20 years, I have found the following 2 methods of cloud determination.

1.  The crude method, which consistently over-analyses low clouds and under-analyzes high clouds.  It is a combined function of the Temperature/Dew-Point spread (T/Td) and lapse-rate.  Details can be found on the attached page of the RAOB User Manual, where it lists the T/Td thresholds and critical Lapse-rate for the Standard (crude) cloud method. 

2.  The more advanced (or RICAPS) method, employs many layers of algorithms based on the latest thinking of the meteorological community.  The methodology use the following elements to determine cloud bases and heights: T/Td, Lapse-rates, Temperature Inversions, Wetbulb & Frostpoint Temperatures, and thermal bouyancy produced by the cloud condensation process which releases heat and thus directly influences the cloud tops.  RAOB is the only sounding program which incorporates all these parameters into a working cloud model > http://raob.com/ricaps.php

It is important to note that RAOB produces cloud (and many other parameters) based solely on a single sounding profile.  Much more intelligence can be obtained from a network of soundings across a region, and thereby produce better cloud analyses -- and these of course are commonly available from the many gridded, numerical module datasets available on the Internet.
John Shewchuk