The estimation of large‐scale vertical currents from the rate of rainfall
Abstract The depressions of middle and high latitudes cause the raising of large masses of air from low to high levels in the troposphere. As the air is lifted it soon becomes cooled below its saturation temperature and its surplus water vapour condenses into cloud particles and later into rain or o...
Published in: | Quarterly Journal of the Royal Meteorological Society |
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Main Author: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
1948
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Subjects: | |
Online Access: | http://dx.doi.org/10.1002/qj.49707431906 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.49707431906 https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.49707431906 |
Summary: | Abstract The depressions of middle and high latitudes cause the raising of large masses of air from low to high levels in the troposphere. As the air is lifted it soon becomes cooled below its saturation temperature and its surplus water vapour condenses into cloud particles and later into rain or other forms of precipitation. Thus the rate of rainfall is a rough measure of the rate of lifting, or the upward velocity, of the air above. It is shown here how this measure may be made more precise when it is certain that the lifting process is on a large scale and comparatively uniform and not influenced by local instability effects. Examples of the application of the method are given, and it appears that upward velocities of from 10 to 20 cm. per second ( i.e. 9 to 17 km, per day), are usual in the active depressions often experienced over the North Atlantic. |
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