376 MONTHLY WEATHER REVIEW S-, 1926
4
TABU 3.-Total number of eriods of two or more comecutive days i n whuh wind movement 8 d not equal 10 miles per hour for five
01 more consecutive hours each day, for the 10 years 1916 to 1941, i n d d o e , d Lincoln, Neb.
--
8 9 \4
0 2 0 0 0 1 0 0 0 0 0 0 0 0
0 0
0 0
0 0
0 0
0 0
0 0
-
-
_I
0 ,"
B o p
-2 5 5:
s -';
-
2
3
4
5
6
7 8
9
10
11
12 18
14
16
16
-
6
3
3
1
-
s B M
-
11 5 1 0 0 0
1
0
0
0
0
0 0
0
1
-
--~
17 120 7 57
4 29
1 12 2 1 8
0 0 4
0 0 3
0 0 0
0 0 1
0 0 0
0 0 1 0 0 1 0 0 0 0 0 0
-
5 ij
-
11 2 1 1 0 0 0 0
0
0
0
0 0
0
0
- 0 1 0
-
CI
d -
3 1
1
0 0 0 0 0 0
0
0
0
0
0
0
-
1
Lincoln (84 feet)
~ ~
__
~
- ______ North Platte (51 feet) _______ O-a(122fe&3.-.:-: ______ @JoU.CitJ, IO- (164 feet)-- r h o r i ~(M f ~t ) _____._____
3 cr -
5
4
1
4
0
1
0
0
0
0
0
0
0
0
a
-
I 1 10.7 11.3 12.6/13.0 11.2 10.1 8.9 8.61 9. iI10.5 10.4 10 3 10.6
7.6 8. 1 9,5110. 4 9. 1 8. 1 7.2 6.8 7.5 7.8 7.61 7: 4 8. 1
9.1 9.710.1'10.1-8.9 7 .~(i t /6 .7 1 7 .1 1 2 8.618.7 8.5
12 3 12 7 13.6114.6 13.2 11.8'10.1 9.9 11.4 12.2 11.9 11.6 12.1 9.8 9.811.~,124ll16IO.7~ 9 .7 /9 .l ,l 0 .0 ,1 0 .2 ,9 .i ~9 .5 1 0 .3
x
2
10 6
-
8
2 0
2
1 0
0
0
0
0
0
0
0
-
4 B -
13
9
6
3 0
1
0
0
1
0
0
1
0
0
0
-
-
3 4 g m
17 5
2 0 1 1 0 0 0 0
1 0
0
0
0
__
-
4
Y
B -
12 3
2 0 1 0 0 0 0
0 0
0
0 0
0
-
Since the amount of electricity used on farms depends mainly upon the amount used for lighting purposes, more electricity is consumed during the months when nights are longer, and the batteries then require more frequent charging. A comparison between the holm of
f rH R M J J H s 0 N D
-50
n,
5"
$30
a
FIG. I.-Percantage of hours with wind velocity equaling or exceeding 10 miles r hour (unbroken line), and percentage of hours of dark- neaa (brogn h e ), at Lincoln, Nebr., for the 10 ymrs, 1912 to 1921.
inclusive
TABLE 4.-Recorded average hourly wind movenient (miles) nt certain Weather Bureau stalion8, with height of anemometer
darkness and the wind movement is given in Figure 4.)
Darkness is considered as beginning one-half hour after sunset and ending one-half hour before sunrise. The average wind velocity a t the regular Weather Bureau stations in Nebraska and also a t the neighboring station a t Sious City, Iowa, is shown in Table 4. The height of the anemometer a t each station is shown. Since wind velocity increases with increase in elevation, the height of the anemometer should always be considered when comparing records from different stations. In order to ive a better comparison of the wind move-
were reduced to a common level. Bs the windmill at the Agricultural College at the University of Nebraska is
60 feet high the averages were reduced to this level. The formula used in making the reductions was suggested by Stevenson in the Journal of the Scottish Meteorological Society in 1880:
ment a t the di i erent weather bureau stations the averages
in which V is the computed velocity for the level H, in terms of the known velocity v, a t the known height h.
While there may be a small error, they undoubtedly give a better indication of the variation in wind movement over the State t'han the actual averages in Table 4.
These computed velocities are given in Table 5.
TABLE ~5 .-~O t I l p i t ~~t ~ iwernye Itoiwlg wimf ittovernent (miles) at
stations yisen in tttble 4 , redtcced to uji ckiiafi07~ of 60 f e e f
- -, - - _--_
Lincoln ..................... NorthPlattc __._.___._._.___
Omaha ..______..__.______. :.
SlouxCity,Iowa ...... _.__ __ Valentine. - __ ____ - __. . . . . ~.
~
In conclusion it, inay be said that while the data pre- sented may not prove the feasibilit of operating electrical
ties. It would seem that here is a fruitful field €or further investigations. The day may'not be far distant when hbndreds of rural homes will have wind power plants for generating electricity.
generators by wind power, they a t 9 east show the po.ssibili-
CLIMATOLOGJCAL DATA FOR ANDAOOYA, REPUBLJC OF COLOMBIA, SOUTH AMERICA
By P. C. DAY
[Weather Bureau, Washington, D. C.. bug., 19281
Through the cburtesy of Mr. E. H. Westlake, vice resident, Pacific Metals Corporation, 61 Broadway, kew Yark, N. Y., the Weather Bureau has received regularly for a number of years, copies of bhe monthly meteorological records made a t the mining camp of that corporation a t Andagoya, located on the San Juan River in the northwestern art of Colombia, South America.
are, latitude 5' 4' north, longitude 76' 55' west, in the Choco district, a t the junction of the San Juan and Condoto Rivers, and about 250 feet above sea level. On the west the distance in a direct line to the Pacific is about 35 miles, while to the east lie the Western Cordillera of the Andes a t a distance of about 50 miles. These mountains are from 4,000 to 5,000 feet above sea level.
The geographic coor f inates of the place of observation
Between the San Juan River and the Pacific coast liea a
range of hills not over 300 feet above sea level. The instrumental equipment consists of maximum and minimum thermometers, rainga e, and hygrometer, all
mometers are read daily and the precipitation is measured twice daily, 7 a. m. and 7 p. m., local sun time. Observations of rainfall began in August, 1914, and of temperature in September, 1917. A short record of relative humidity was made during portions of 1917 and
1919.
In addition to the above a record of precipitation covering about t,hree years was furnished by the same company from a branch camp at Buena Vista, about 25 miles north of the main camp at Andagoya.
of standard make and propery B exposed. The ther-
SRrnMBER, 1996 MONTRLY WEATHER REVIEW
TABLE 1.-Meane and ertremce of temperature (OF.), 1917-1996,
Andagoya, Colombia
M e a n m n r - I minm _._____ 59.6 89.3 89.6 89.8 89.2 W.2! 89.3 89.2
imum _______ 74.51 74.5 74.5 75.0 74.5 74.lj 73.6 i3.6
b9.5
73.5 Mean ______ .--. 83.0 S1.9 82.0 82.4 81.S 81.G 81 4 SI 4 81.5
Lowest ____..__ 68 I !! 70 70 72 rO 1 70 70 70
Mean m i n - I
Highest ___..._ 96 98 97 96 100 110. 93. 100
The mean annual temperature 81.6' is exceeded in very few regions of South America. The following means are of interest in this connection: 82.4' at Quixeramobim, State of Ceara, Brazil; 82.6' at Dada-Nawa in southern British Guiana; and 83.5O at Maracaibo, Venezuela. In the warmest months, January t,o April, the mean tem-
perature a t Andagoya averages 82.1'.
TABLE 2.--MonthZy and aiitLiinl precipitcilioiL (it1 inches), Bdagoya.
Colombia
1 Hours of mesurenicnt changed t o 6 p. ID. and 6 n. m. in March, 192.5.
The temperature is unusually uniform throughout the year; during the eight-year period, the maximum ob-
served, 100' F., was recorded on ody four day, the
minimum of 66O on but one date, and the minimum Wnb
below 70' on only five da s.
record at Andagoya show the rainfall to be rather uni- formly distributed over the several seasons, as well as
over the different years of the period, a feature not usual in regions with such heavy anniial amounts. Individual monthly totals ranged from 8.55 to 47.83
inches, but they were generally between 20 to 30
inches. The feature of outstanding importance in the distri- bution of precipitation is the great frequency snd inten- sity of night rains. The average annual number of nights with rain is 277, while the average for the day falls to 158. Nearly SO per cent of the precipitation occurs between 7 p. rn. and 7 a. m., as shown in the table given, and for this period the mean intensity for nights with rain is about 0.80 inch as compared with Iess than 0.40 inch for the daytime intensity. Contrary to what niight well be expected, the extreme amounts of precipitation recorded in 34 hours are rather mdarste, and those for 13 hours are not excessively high. The niasimuni amounts for these periods are due to heavy downpours at night, the heaviest fall for any 12-hour
period of daylight being oiily 3.10 inches. At Buenn Vista the averagc for the three-year period
is niore than 50 iiiches greater than a t Andagoya, but the nie~1s~reiiieuts there are 11lRde once daily only apd the relative proportions for then day and night periods
The individua' month s y amountsfor the period of
are not showIi.
~
The mean annual precipitat,ioii of 379 inches a t ' ildagoya and an eren greater amount, 331 inches, at,
the sub-station, Buena Vista, together with a 7-year aver- age precipitation of about 280 inches as recorded from
1910 to 1916 at Buenaventura, located south of Anda- go II a t thc niouth of the San Juan River, show remark-
the Cordillera Occidental, the western range o the Andes. The decrease in annual rainfall from the coast to the elevated interior amounts to more than 250 inches, as shown in the following table. The marked differences in the annual amounts are likewise maintained in the monthly amounts for the different seasons.
$
ab 9 e contrasts to those occutring in the re ion east of
I 5 O 4' N.. 7R" 55' W.. elevation 250 feet.
? 5" 30' N. r6'51' W.. elevation not gireu.
2 io 49' N::'77" 11' W., mar sea level. Period, 191Cb1916. '6" 10' N., i5' 45' W., elevntion 4,950 feet.
I 3' 36' N., 76' '27' W., elevatinn 3..W feet.
0 4' 36' N., 74' 5' W., elevation 8.iOO feet.
Sources of d%tc:
Period, 1814-1925. Period. 1RZ-lH2S.
Periods, 18i5-18iS and 1908-1R18. Period. 1W1910. Period. 1894-1922.
BUENA+ENTURA AND BOGOTA: P.\nasor.n. 6.. Noticis del nuevn ohscrvstorio (8an Bartolorn6 de Bogotb) con nlgunos datos sobre la climatologia y magustfsm0 de
MEDELLIN: Clim,atologicaI Data West Indies and Caribbean Service. U. S. Weather Bureau. July 1925, LA MANUELIT-4: CHAPMAN, F&K M.. ~:i c Distrihution of Bird Life i n Colombin. Rtrtletin O J ~~M 'Amtriean Mi1reu.m OJ X Q I U T U ~ Eirlory, ro1.36. 1gli.
Colombia. Boeota. 1021.
The annual precipitation over the coast districts and lower valleys of northwestern Colombia, nearly 300
inches, as shown in the above table, is appmently the
lrighest that occurs in either North or South America, being considerably in excess of the amount received a t Mooretown,. J e a i a ,, 222 inches,. , or, ~t . Gm,vt9,wn, Nicaragua, 256 inches.
In commenting on the heavy precipitation in that
region, the assistant. manager of the company, Mr. N. C. Marshall, states:
Certain months are supposed t,o be dry, butthey will not be 80
regularly every year. . The day rainfall 18 fairly constant, at an average of from 4 t o G'inches per month. The-only thing that can he said about the night rainfall is t.hat more rain .fdlg-fiom
378 MONTHLY WEATHER REVIXW ~TEXBEB, 1996
h i e td N u m b e r than during the other months of the year. Tbia i n c l u b the time when the big floods come down the San Juan and Condoto Rivers, which may be espected during, the months of Se tember to November, and much less frequently during the otEm months. What dry sewon there is will come from December to May, although it can not by any means be called dry. In regard to the rainfall during the day, the greatest part of it falls from 7 to 9 o’clock in the morning and from 5 to 7 in the evening. If it were otherwise, i t would be very hard to.get any outaide work done at all, but there are really more sunshiny days than the record of rainfall would lead one to suppose. It is rather uncommon for rain to continue falling all day long and if these days were kept track of, I think that it would be found that the most of them occur during the months of heaviest rainfall from June to November. For this reason this time of the year has
been called the wet season, and from December to May the dry
Pearon, but the rain gage does not bear this out; as, for instance, the second highest monthly rainfall on record, 39.15 inches, occur- red in April. The native way of naming the seasons is very simple and quite flexible; when a few consecutive days are rainy they my I! is winter, and when four or five days have been bright aud sunshiny they call it aummer, no matter what time of the year it may happen to be.
Commenting on the la e amount of precipitation dur-
With regard to the preponderance of recipitation during the night this is a feature of the climate which f have heard commented upon by the half-dozen or more engineers whom we have sent to Colombia since 1912. I n fact this feature of the climate of the Choco region was noted and commented upon as far back 88 1864
in an article by John C. Trautwine (author of the well-known engineering handbook and one of the builders of the Panama Railroad) in a paper entitled “Rough Notes of an Exploration for an Inter-Oceanic Canal Route by Way of the Rivers Atrato and San Juan, in New Granada, South America, see journal of the Franklin Institute, March t o October, 1854.”
The only records of relative humidity are those at noon covering parts of the years 1917 to 1919. No data appear for August or September of any of those years. Interpolation of values for these months gives the unusu- ally high value of 82 per cent at noon for the annual mean. The extremes of the monthly means are 86 per cent in February and 78 per cent in October.
ing the night hours, Mr. % estlake states:
C. E. P. BROOKS ON VARIATIONS OF PRESSURE FROM MONTH TO MONTH IN THE RECilON OF THE BRITISH
ISLES 1
By A. J. HENRY ss/.54 (40
In this study the author has used the data of month1 deviations from normal pressure for the stations published in RDeau Mondiul to trace the shifting in latitude and ldngitude from month to month of the centers of greatest deviation in the region of the British Isles. Only the
pressure deviations were dealt with, since those of
tern erature and precipitation can be explained in terms
The monthly charts afforded litble insight into the resure distributions which were rdspbnsible for them ;
!mce it became necessary to examine the daily weather charts for the months considered.
In the beginning the progressive movement of these centers was studied by constructing a series of overlapping 30-day charts March 1 to 30, March 2 to 31, and so on. These charts ve clearly showed the gradual movement
deficit. The construction of 30-day overlapping charts being too laborious, a t the suggestion of Dr. George C. Simpmn, a shorter method was adopted.
In this method the area covered was that between 30’ and 70’ north latitude and 70’ wesb to 80’ east longitude and only deviations of at leist f5 mb. were considerad. When deviations of that amhunt occurred
in two euccessive months a barbed line w b drawn con- necting the pobition of the center during the first month with its position in the second month.
If these centers in succemive months werg as a rule quite inde- pendent of each other, there would be no reason why theae arrows should be directed toward one point of the compass rather than another. If, on the other hand, the center6 in successive months really indicate two successive positions of the same center, and if there is a tendency for centers to move in one direction rather than in another, the majority of the arrows should point in this direction. The investigation was carried out on three separate series of charts, which between them cover a period of 41 years:
(a) A series of monthly charts of pressure deviations over the northern hemisphere covering the years 1873 to 1900.
(a) Working charts of deviations of pressure over the globe for
the period January, 1910, to April, 1919, prepared in connection with the R4aeau Mondial.
(c) A aerie8 of rough working charts of the deviations of pressure over North America, the North Atlantic, western and central Europe, covering the period June, 1922, to October, 1925, pre-
of t % e pressure.
in a northeestery Y direction of the areas of excess or
* Qurbxly Journo 1 of the Royal M eteorologicd Soc. 6k ft9-2%.
pared in co~inectioii with varioua investigations into current weather. The Rdseau Mondial charts were the first set to be dealt with, and it was quickly evident that the movements of the centers in the southern half of the area were very largely from west to east, while in the northern half there were a considerable number of instances in which the movements were apparently from east to west. The work was accordingly repeated, the pairs of months being separated into two classes, the first class including those in which the position of the center during the first month was north of 55O N., while the second class included those in which the posi- tion of the center during the first month was south of 55O N. The results of the investigation are shown in Table I (not repro- duced). * * * From Table I we see that between 70’ and 55’ N. 60 centers of
excess gave an apparent movement to the eastward compared with 35 to the westward, and 60 centers of deficit showed a move-
ment to the eastward compared with 49 to the westward. Between 55’ and 30’ N. 41 ccnters of excess showed a movement to the eastward compared nith 15 to the westward, and 23 centers of deficit showed a movement to the eastward compared with 16 to the westward. In all four groups the easterly movement pre- dominated, although to a much greater extent with centers of excess than with centers of deficit. The predominance of apparent easterly movement holds in all four seasons, thou h i t is greatest in summer. We find that for each 10 centers o f pressure deviation giving apparent weatward movement in any one season the number of centers giving an apparent movement to the eastward is: Winter 12, spring 17,
summer 21, autumn 16. Many of the instances of apparent move- ment to the westward are due to the happenin&th&t a center of deviation which was shown in the chart for one onth had by the following month either moved eastward out of t3 a ea or had d a creased to an intensity of less than 5 mb., while it [hq same time a new center of deviation had appeared in the west of the chart.
It appears in fact that the month is too big a ubit; if the charts had been drawn for each 10 or 15 days, the predomitidpce of ap- parent easterly movement would have been much grestbr.
Tracks of centers of excess and deficit Yere con- structed and published. These followed more or less regular courses, somewhat analogous to the paths of cy- clones that apparently circle the north pole. The centers of excess show a tendency to move from Alaaka south- eastward to the center of the United Statei, thence east- ward to a position between Bermuda and Nova Scotia, continuing in that direction to the Azores, bhence usually northeastward to the British Isles or across them to Scandinavia, and finally again eastward intd northern Russia or the Kara Sea, the whole journqf taking about six months, though no single center was f e u d - that per- sisted long enough to move from-Alaska to Russia.