Diurnal Weather Patterns— Leopold 
93 
breeze effects. Yet the magnitude of the diurnal 
change in height, admitting a very incomplete 
record at Honolulu, appears to be greater at 
Honolulu than at Los Angeles. Third, the dif¬ 
ference in inversion height between scheduled 
radiosonde times at the ship '‘Bird Dog” is 
greater than that for the west coast and less than 
the difference at Honolulu. It is in the same 
phase as that at Honolulu. These heights and 
those of California stations are summarized in 
the following table. 
Thus it appears from limited data that the 
diurnal curve of the temperature inversion does 
not fit easily into the explanation which appears 
reasonable for the California coast. There is 
apparently a diurnal change in height over the 
open ocean, felt by near-coast and insular loca¬ 
tions, which is not explained by sea-land-breeze 
effects. 
The same kinds of diurnal temperature 
changes in the atmosphere aloft above the inver¬ 
sion were noted at Honolulu as were described 
for California (Leopold and Beer, 1947), i.e., 
an appreciable warming during the daytime. 
There is still some question whether this 
measured diurnal temperature change in the free 
air aloft is real or whether insolational heating 
of the radiosonde provides an appreciable por¬ 
tion of the increase. If these cyclical tempera¬ 
ture changes prove to be real, they might indi¬ 
cate a diurnal cycle of vertical motion quite un¬ 
related to sea-land-breeze effects which would 
affect the height of the inversion. 
RELATION BETWEEN VARIOUS DIURNAL 
PHENOMENA 
Loveridge’s (1924) curves for the diurnal 
variation of rainfall for Honolulu, 1905-23, are 
well verified by Parker’s tabulations (see p. 84) 
for the same stations for 1923-41. The occur¬ 
rence of trade-wind rains primarily at night has 
been discussed by Loveridge (1924) and Jones 
(1939). The former noted the out-of-phase 
relation of surface wind speed at Honolulu and 
the rainfall. With the night wind speed ex¬ 
plained by stability in the lower layers, the ques¬ 
tion is raised concerning the relation of rainfall 
to the temperature inversion. It might be argued 
that the lower cloud tops at night which should 
accompany a lower nighttime inversion would 
reduce the tendency for precipitation at the 
same hours. The effect of cloud height alone is 
probably minimized by the fact that none of the 
clouds providing the trade-wind rain reach into 
freezing temperatures. 
Wind speeds aloft actually increase some- 
TABLE 2. DIURNAL CHANGES OF TEMPERATURE INVERSION—LOS ANGELES TO HONOLULU 
SAN 
CLEMENTE 
ISLAND 
STRATUS 
SHIP 
U.C.L.A. 
SANTA 
ANA 
SHIP 
“BIRD DOG” 
HONOLULU 
Miles from local coast 
60 off shore 
10 off shore 
5 inland 
8 inland 
0 
Maximum height in 
feet. 
2,300 
1,600 
1,850 
1,600 
8,400 
Minimum height in 
feet. 
1,700 
1,100 
1,200 
750 
6,300 
Time of maximum 
height. 
0630 
0630 
1100 
0800 
1100 
Time of minimum 
height. 
1130 
1300 
2200 
1930 
2200 
Difference in height 
0530-1730 LST feet 
300 
400 
200 
650 
550* 
540f 
700 
* Ship "Bird Dog” data for November, 1946; f '’Bird Dog” for September, 1946. 
Notes: Honolulu data for November, 1946, and May-June, 1947. 
California data for "ship period,” 2 weeks in September, 1944. 
Times are local standard for respective longitudes. 
