14
From Obsevations at 9.30 A.M. and 3.30 P.M.
Corrected forDiurnal Inequnlity
Belgaum
Poona
..
.»
Bombay .. '..
Deesa
Karachi
Belgaum
Poona
Bombay
Deesa
Karachi ..
+ •094
+ •120
+ •129
+ •208
+ •246
+•089
+ •118
+ •127
+ •201
+ •239
+•067
+ •086
+•006
+•151
+•182
+ •064
+ •085
+ •097
+ •144
+•178
+•031
+•039
+•050
+•080
+ •128
+ •030
+ •043
+•052
+'083
+•117
—•019
—•015
—•013
—•C19
-•019
—•016
—•013
—•012
—•024
—•016
—•048
—•065
—•053
—•088
—•129
—•049
—•063
—•054
—•091
—•133
—•098
—•146
—•156
—•241
-•271
—•096
—•145
—•157
—•234
—•271
—'096
—•141
—•159
—•268
— -306
—•095
—•142
—•158
—•261
-•304
—•062
—•092
— -Í03
—•193
—•226
—•062
—•096
—•096
—•190
—•232
—•032
—•044
—•040
—•078
—•096
—•025
—•043
—•038
—•070
—•089
+ •009
+ •029
+•022
+ •050
+ •056
+ •011
+ •029
+ •020
+ •050
+ •064
,
+ •065
+ •104
+ •094
+ •177
+ •118
+ •062
+ •102
+ •090
+ •176
+ •189
+ •089
+•129
+•181
+•218
+•256
+ •080
+ •128
+•126
+ •215
+ •251
" The numbers in the above table are curved in figures 283 to 287. The figures are all
of similar form, having values near the maximum from December to January in the case of
Karachi, and for November to January at the other stations, and values near the mini-
mum in June and July, and with gradual progressions from maxima to minima and from
minima to maxima.
" The range between the greatest and least monthly means increases with the latitude,
and is about three times as great at Karachi as at Belgaum : its values at the several stations
taken in the order of their latitudes, viz., Belgaum, Poona, Bombay, Deesa and Karachi, are
0.185, 0.273, 0.285, 0.476 and 0.555 inch respectively. Any influence that height of the
station has upon the annual range—and we cannot suppose the pressure of a column of more
than 2,000 feet in height to be exactly the same at all seasons—does not alter the order which
the numbers follow as affected by change of latitude.
" The following table exhibits the amplitudes of the oscillations of pressure in averages
for the year and for the monsoon months :—
Average Daily and Night Ranges of Barometric Pressure, or the Ranges between the A.M.
Maximum and P.M. Minimum, and between the P.M. Maximum and A.M, Minimum for
whole year, and for the months June to August.
Belgaum
.
•
Poona
Bombay
Deesa
Karachi
DAY.
Year.
Inch,
•097
•117
•102
•106
•082
June to
August.
Inch.
•062
•080
•072
•091
•061
NIGHT.
Year.
Inch.
•041
•070
•051
•027
•030
June to
August.
Inch.
•044
•062
•057
•024
•030
" At the 3 first stations the day range of the monsoon is only about two-thirds of the
average of the year, and'the night range is considerably larger than at the two northern sta-
tions. Comparing Bombay with Poona and Belgaum, we see that the absolute diurnal range
is about as great on the Deccan plateau, at an elevation of 2,000 feet, as in the Konkan near
the sea level, a fact which seems to associate this variation rather with the general ground
level than with the mean sea level.
"The next table shows for each month of the year the greatest and least values of baro-
metric pressure observed at 9-30 A.M. or 3-30 P.M. at the several stations.
"It will be noticed that whilst the lowest minima occur at all the stations, with a scarcely
perceptible exception at Karachi, in June, the lowest maxima occur with scarcely perceptible
exception at Belgaum, in July. Generally the movements both of the maxima and minima
are similar to those of the mean barometric pressure, the largest values occurring about
the winter solstice and the smallest values about the summer solstice, with gradual
intermediate progressions.