F 3
III. METEOROLOGICAL OBSERVATION AT THE OBSERVATORY,
Automatic records of the temperature of the air and evaporation were obtained with a Richard dry and wet bulb thermograph, and of the direction and velocity of the wind with a Beckley and a Dines-Baxendell anemograph, modified as described in the report for 1912. The amount of rain is recorded automatically by a Nakamura pluviograph, the amount of sunshine by two Campbell-Stokes universal sunshine recorders, and the relative humidity of the air by a small Richard hair hygrograph. Eye observations of barometric pressure, temperature of the air and of evaporation and the amount of cloud are made at each hour of Hongkong Standard time. The character and direction of the motion of the clouds are observed every three hours. Daily readings are taken of self-registering maximum and minimum thermometers.
Principal features of the Weather.-The principal features of the weather in 1921 were:-
(a) Heavy rainfall from April 27 to July 6, during which period 59 inches of rain fell on 59 days; and a drought from September 9 to the end of the year when only 1 inch of rain fell.
(b) Abnormally low wind velocity in March, increasing gradually to normal in July.
Barometric pressure was considerably above normal in January, July and October, and considerably below in May, June and August. The mean pressure for the year at station level was 29.848ins., as against 29.814ins. in 1920 and 29.843ins. for the past 38 years. The highest pressure was 30.323ins. on January 14, as against 30.374ins. in 1920 and 30.509ins. for the past 38 years. The lowest pressure was 29.319ins. on July 24, as against 29.208ins. in 1920 and 28.735ins. for the past 38 years.
The temperature of the air was moderately above normal in February, March, April, August and December and moderately below in January. The mean temperature for the year was 72°.2, as against 72°.0 in 1920 and 71°.8 for the past 38 years. The highest temperature was 92°.2 on August 22, as against 93°.1 in 1920 and 97°.0 for the past 38 years. The lowest temperature was 44°.0 on February 4, as against 45°.1 in 1920 and 32°.0 for the past 38 years.
The rainfall was very considerably above normal in May and moderately above normal in March, August and September. It was considerably below normal in April, October, November and December. The total for the year was 97.34ins., as against 107.88ins. in 1920, and 84.62ins. for the past 38 years. The greatest fall in one civil day was 6.06ins. on September 3, and the greatest in one hour was 3.25ins. between 1.30 p.m. and 2.30 p.m. on May 31.
The mean wind velocity was considerably below normal in January, March, April, May and October. In July it was normal and in the remaining months it was slightly below normal. The mean velocity for the year was 10.7 m.p.h., as against 12.0 m.p.h. in 1920 and 12.7 m.p.h. for the past 38 years. The maximum velocity for
F 3
III. METEOROLOGICAL OBSERVATION AT THE OBSERVATORY,
Automatic records of the temperature of the air and evaporation were obtained with a Richard dry and wet bulb thermograph, and of the direction and velocity of the wind with a Beckley and a Dines-Baxendell anemnograph, modified as described in the report for 1912. The amount of rain is recorded automatically by a Naka- mura pluviograph, the amount of sunshine by two Campbell-Stokes universal sunshine recorders, and the relative humidity of the air by a small Richard hair hygrograph. Eye observations of barometric pressure, temperature of the air and of evaporation and the amount of cloud are made at each hour of Hongkong Standard time. The character and direction of the motion of the clouds are observed every three hours. Daily readings are taken of self-registering maximum and minimum thermometers.
Principal features of the Weather.-The principal features of the weather in 1921 were:-
(a) Heavy rainfall from April 27 to July 6, during which period 59 inches of rain fell on 59 days; and a drought from September 9 to the end of the year when only 1 inch of rain fell.
(b) Abnormally low wind velocity in March, increasing
gradually to normal in July.
Barometric pressure was considerably above normal in January, July and October, and considerably below in May, June and August. The mean pressure for the year at station level was 29.848, as against 29.814in in 1920 and 29.843ins for the past 38 years. The highest pressure was 30-323ins. on January 14 as against 30-374. in 1920 and 30-509ins for the past 38 years. The lowest pressure was 29-319ins on July 24, as against 29-208ins. in 1920 and 28-735. for the past 38 years.
The temperature of the air was moderately above normal in February, March, April, August and December and moderately below in January. The mean temperature for the year was 72° 2 as against 72°0 in 1920 and 71°-8 for the past 38 years. The highest temperature was 92°-2 on August 22 as against 93°1 in 1920 and 97°0 for the past 38 years. The lowest temperature was 44°-0 on February 4 as against 45°1 in 1920 and 32° 0 for the past 38 years.
ins.
The rainfall was very considerably above normal in May and moderately above normal in March, August and September. It was considerably below normal in April, October, November and December. The total for the year was 97.34 as against 107·88ins. in 1920, and 8462ius for the past 38 years. The greatest fall in one civil day was 6'06 on September 3 and the greatest in one hour was 3.25 between 1.30 p.m. and 2.30 p.m. on May 31,
ius..
The mean
The wind velocity was considerably below normal in January, March, April, May and October. In July it was normal and in the remaining months it was slightly below normal. velocity for the year was 107 m.p.h. as against 12'0 m.p.h. in 1920 and 127 m.p.h. for the past 38 years. The maximum velocity for
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