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The relation between standard deviation of contour height and standard vector deviation of wind
Author(s) -
Jenkinson A. F.
Publication year - 1956
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49708235206
Subject(s) - standard deviation , latitude , mathematics , geodesy , absolute deviation , mean value , contour line , wind speed , geology , meteorology , statistics , physics
A formula is derived, believed to be valid for all places outside the tropics and at all levels between the top of the friction layer and about 300 mb, expressing standard vector deviation of wind as a constant multiplied by the product of the standard deviation of contour height and the cosecant of latitude. The formula may be written σ = 0.064 s cosec where a is the standard vector deviation of wind in kt, s is the standard deviation of contour height in ft and ϕ is the latitude. A similar relationship is derived for levels between 300 mb and 100 mb. We may write σ = κw cosec ϕ where κ has the same value at all places but decreases uniformly with height from 0.064 at 300 mb to 0.033 at 100 mb. World seasonal maps of the standard vector deviation of wind immediately above the friction layer have been prepared from corresponding maps of the standard deviation of surface pressure; and seasonal maps of standard vector deviation of wind at 500 mb over part of the North Atlantic were prepared from maps of standard deviation of contour height computed directly from daily values.