New-York tribune., 1892-08-17
SOME ANOMALIES IN Wind VELOCITIE'

Charts have recently been published by the
United States Weather Bureau showing the mean
direction and velocity Of the wind at large
number of stations H. this country during the
different months They are valuable, Doth 10
those persons who wish to study in detail the
meteorological conditions Of any particular locality
and 10 students Of the general laws that govern
winds. While a majority Of the results herein
embodied harmonic finely with each other ana
with observations in other lands, there arc some
curious exceptions which provoke inquiry as 10
the causes TO which they are attributable.
Two OF these apparent anomalies are 70 De
found on the Pacific Coast. In most regions
living at low levels and In temperate latituces. the
wind attains its maximum velocity at the warnest
hour, OF the day: that IL, between ana
o'cloclt in the afternoon. The minimum occurs
az the coldest hours or just before dawn. Blu
Professor Harrington's new wind-charts show thas
in portions Of Oregon, California and Arizona, ana
al points even further inland, the maximum usu-
a.lv occurs between 5 and o'clock p. m. lbs
cause OF this retardation may, perhaps, be some
influence exrried by the Sierras ana Rocky
Maintains The system OF diurnal changes In
velocitv NJ great elevations, as upon Pixies Peak.
- c.ac,lv the reverse Of that prevailing on ada
cent plain. Even at the top OF the Eihel Tower,
scarcely 900 feet high. the highest velocity b
M, u.uallv attained until 10 or II o'clock mt
night. or about nine honrs behind the climax
AZ the Central Weather Office in Paris, only sixty
feet above sea-levcl
Another notable fact IL that this same average
daily maximum exceeds the mean minimum 70
GREATER degree on and near the Pachc Coast tnah
IL docs elsewhere in the United States especially
in summer At. ST. Paul, Omaha, Galveston'
Louisville, Buffalo, Boston and Charleston. ior
instance the highest daily speed in winter is from
IS 10 20 per cent. greater than tho lowest III
summer. from 80 TO l25 per cent But at for'-
land. Roscburg lOregon), San Francisco Dan
n,ogo yuma Arizona Boise City tldaho and
Salt Lake City the increase In winter Is nearly
or quite 100 per cent, while In July IL ranges
from $50 10 $50 per cent IN most cases ae
po..hury il averages coo, That the orographi-
cal features Of the western part OF the continent
!, \ measure account for this difference is clearcr
than their share in producing rctardauon OF
m,x,mo II has benn pointed out by Laughton
that the phenomenon known as tile sea Drceze
uch, wind often observed In summer, setting
inshore in the warmer part OF the day-prcvaiis
n n greater extent where the coast thus visited
has A mountain range for its background Inc
uocoual effects OF solar heat upon land and sea
flow appears TO be more conspicuous with high
lands than lowands The usual summer WIND
an the Pacific Coast Is true sea breeze; anu the
conditions mentioned by Laughton as promoting
il are there admirably afforded. What Is true
of the effect Of mountains upon breeze which, IL
II could be separated from all other atmospheric
motions would last only a few hours at a time Is
also true of that continuous though gentle, mon
soon-likc wind which in summer flows night ana
dav from the permanent areas OF high Darometric
pressurc lying over the ocean toward the great
stationary continental low areas. The Coast
Range. Sierras and Rockies, and no doubt the
vast mountain plateau, thus operates with double
effect at tho warmer period Of the year. 1t VIII
no remembered, moreover, that in our ATTITUDES
there is q broad, deep, permanent airstream now
the oceans il dips TO the surface Of The water most
NJ the time; and even over tile continents Its
under side Is rarely more than a mile or two from
the earth The tendency of this great current
would be TO accelerate by friction any atnos-
nhcric movement going on underneath it in the
same direction. such as the monsoon and sea
brccze OF the Pacific Coast, but to rctard such as
proceeded in nearly contrary direction; the
southeastcrly winds that favor the Atlantic sea-
hoard in summer, for instance.
These and some other peculiarities of Ameri-
can winds revealed by the charts in question
deserve. and will no doubt receive, careful cx-
animation.