165:); hence clouds exchange thermal radiation between their bases and the underlying planetary surface (land or ocean) by absorbing and re-emitting this infrared radiation at the prevailing temperature – the lower the cloud base, the warmer the cloud particles and the higher the rate of emission. For a synthetic discussion of the impact of clouds (and in particular the role of cloud bases) on climate systems, see the
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Divide the spread by 4.4 (if temperatures are in °F) or 2.5 (if temperatures are in °C), then multiply by 1000. This will give the altitude of the cloud base in feet above ground level. Put in a simpler way, 400 feet for every 1°C dew point spread. For metric divide the spread in °C by 8 and multiply
146:, many (or even most) clouds may have a similar cloud base because this variable is largely controlled by the thermodynamic properties of that air mass, which are relatively homogeneous on a large spatial scale. This is not the case for the
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The prefix "nimbo-" or the suffix "-nimbus" are low-level clouds that have their bases below 2,000 meters (6,500 feet) above the Earth. Clouds that produce rain and snow fall into this category.
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This article is about the concept in meteorology. For the fictional skyborne headquarters in the
British television series
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Add the results from step (2) to the field elevation to obtain the altitude of the cloud base above mean sea level.
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Cloud base is an important meteorological variable for aviation safety, as it determines whether pilots may use
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in the atmosphere. In the thermal spectral domain, water is a strong absorber (and thus emitter, according to
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Rain clouds and snow clouds are clouds that have their bases below 2,000 meters above the ground.
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Alternatively, the cloud base can be estimated from surface measurements of air
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281:, Her Majesty's Stationery Office, Met. O. 842, A.P. 897, 319 p.
274:, American Meteorological Society, Boston, Second printing-1970.
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FAA Pilot's
Handbook of Aeronautical Knowledge, Weather Theory
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Find the difference between the surface temperature and the
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60:. It is traditionally expressed either in metres or feet
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The height of the cloud base can be measured using a
115:and often named after Tom Bradbury, is as follows:
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36:Photo of a cloud base taken above the island of
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298:National Science Digital Library - Cloud Base
127:by 1000 and get the cloud base in meters.
52:(or the base of the cloud) is the lowest
68:level corresponding to this altitude in
64:or above a planetary surface, or as the
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157:Clouds greatly affect the transfer of
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163:Kirchhoff's law of thermal radiation
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22:Captain Scarlet and the Mysterons
303:Cloud base Measuring instruments
223:. A&C Black Publishers Ltd.
113:Federal Aviation Administration
16:Height of the bottom of a cloud
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169:, in particular chapter 7.2.
135:Weather and climate relevance
167:IPCC Third Assessment Report
56:of the visible portion of a
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180:for take-off and landing.
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342:Meteorological quantities
270:Huschke, Ralph E. (1959)
109:lifted condensation level
72:(hPa, equivalent to the
314:12 October 2007 at the
308:Measuring Cloud Heights
279:Meteorological Glossary
277:McIntosh, D. H. (1972)
272:Glossary of Meteorology
178:instrument flight rules
221:Meteorology and Flight
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62:above mean sea level
174:visual flight rules
107:by calculating the
337:Gliding technology
249:National Geography
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190:Ceiling (cloud)
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253:. Retrieved
251:. 2022-08-09
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200:Cloud height
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70:hectopascals
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195:Cloud cover
101:temperature
94:travel time
80:Measurement
326:Categories
255:2023-09-06
230:0713668318
206:References
152:convection
148:cloud tops
144:air masses
86:ceilometer
50:cloud base
176:(VFR) or
159:radiation
121:dew point
44:, in 2005
42:Indonesia
27:Cloudbase
312:Archived
184:See also
105:humidity
74:millibar
66:pressure
54:altitude
38:Sulawesi
245:"Cloud"
332:Clouds
227:
25:, see
287:p. 14
58:cloud
225:ISBN
103:and
92:or
76:).
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48:A
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