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| uk.sci.weather (UK Weather) (uk.sci.weather) For the discussion of daily weather events, chiefly affecting the UK and adjacent parts of Europe, both past and predicted. The discussion is open to all, but contributions on a practical scientific level are encouraged. |
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#41
May 22nd 05, 06:46 AM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
There was once an occasion when the only cloud around was a CB around
Norwich. I could see this from Guildford on the NNE'ern horizon. Guessing 150m as the CB flies.. Phil |
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#42
May 22nd 05, 06:46 AM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
There was once an occasion when the only cloud around was a CB around
Norwich. I could see this from Guildford on the NNE'ern horizon. Guessing 150m as the CB flies.. Phil |
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#43
May 22nd 05, 06:46 AM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
There was once an occasion when the only cloud around was a CB around
Norwich. I could see this from Guildford on the NNE'ern horizon. Guessing 150m as the CB flies.. Phil |
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#44
May 22nd 05, 09:52 AM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
In article ,
Roger Smith writes: A simple but fairly good approximation is h=d^2/D where D is the diameter of the Earth h is the distance of a point on the Earth's surface below the observer's horizon plane at a distance d from the observer. For determining the visibility of distant objects this formula ignores the effects of refraction. That's fairly small for visible light, isn't it? I know that when working with radar, refraction is commonly allowed for by assuming an Earth radius of 4/3 times the true value. -- John Hall "Acting is merely the art of keeping a large group of people from coughing." Sir Ralph Richardson (1902-83) |
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#45
May 22nd 05, 09:52 AM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
In article ,
Roger Smith writes: A simple but fairly good approximation is h=d^2/D where D is the diameter of the Earth h is the distance of a point on the Earth's surface below the observer's horizon plane at a distance d from the observer. For determining the visibility of distant objects this formula ignores the effects of refraction. That's fairly small for visible light, isn't it? I know that when working with radar, refraction is commonly allowed for by assuming an Earth radius of 4/3 times the true value. -- John Hall "Acting is merely the art of keeping a large group of people from coughing." Sir Ralph Richardson (1902-83) |
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#46
May 22nd 05, 09:52 AM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
In article ,
Roger Smith writes: A simple but fairly good approximation is h=d^2/D where D is the diameter of the Earth h is the distance of a point on the Earth's surface below the observer's horizon plane at a distance d from the observer. For determining the visibility of distant objects this formula ignores the effects of refraction. That's fairly small for visible light, isn't it? I know that when working with radar, refraction is commonly allowed for by assuming an Earth radius of 4/3 times the true value. -- John Hall "Acting is merely the art of keeping a large group of people from coughing." Sir Ralph Richardson (1902-83) |
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#47
May 22nd 05, 11:25 AM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
On Sun, 22 May 2005 09:52:22 +0100, John Hall wrote:
That's fairly small for visible light, isn't it? I know that when working with radar, refraction is commonly allowed for by assuming an Earth radius of 4/3 times the true value. Light is affected by temperature/density variations in the atmosphere, think desert mirages or, closer to home, those patches of "water" on summer roads that disappear as you approach. The latter is a reflection of the sky in the the hot layer of air close to the road surface. -- Cheers Dave. pam is missing e-mail |
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#48
May 22nd 05, 11:25 AM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
On Sun, 22 May 2005 09:52:22 +0100, John Hall wrote:
That's fairly small for visible light, isn't it? I know that when working with radar, refraction is commonly allowed for by assuming an Earth radius of 4/3 times the true value. Light is affected by temperature/density variations in the atmosphere, think desert mirages or, closer to home, those patches of "water" on summer roads that disappear as you approach. The latter is a reflection of the sky in the the hot layer of air close to the road surface. -- Cheers Dave. pam is missing e-mail |
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#49
May 22nd 05, 11:25 AM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
On Sun, 22 May 2005 09:52:22 +0100, John Hall wrote:
That's fairly small for visible light, isn't it? I know that when working with radar, refraction is commonly allowed for by assuming an Earth radius of 4/3 times the true value. Light is affected by temperature/density variations in the atmosphere, think desert mirages or, closer to home, those patches of "water" on summer roads that disappear as you approach. The latter is a reflection of the sky in the the hot layer of air close to the road surface. -- Cheers Dave. pam is missing e-mail |
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#50
May 22nd 05, 02:55 PM
posted to uk.sci.weather
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Furthest you can see a CB cloud?
In article om,
Dave Liquorice writes: On Sun, 22 May 2005 09:52:22 +0100, John Hall wrote: That's fairly small for visible light, isn't it? I know that when working with radar, refraction is commonly allowed for by assuming an Earth radius of 4/3 times the true value. Light is affected by temperature/density variations in the atmosphere, think desert mirages or, closer to home, those patches of "water" on summer roads that disappear as you approach. The latter is a reflection of the sky in the the hot layer of air close to the road surface. Yep. But mirage conditions are the exception rather than the rule (at least in the UK). How much is visible light refracted in the "standard atmosphere"? -- John Hall "I don't even butter my bread; I consider that cooking." Katherine Cebrian |
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