Appendix F.
REPORT OF THE DIRECTOR OF THE ROYAL OBSERVATORY, HONG KONG, FOR THE YEAR 1938.
I. GROUNDS, BUILDINGS AND INSTRUMENTS.
The typhoons of 16-17 August, 1936 and 1-2 September, 1937 demonstrated that the Dines recorder installed in 1910 was incapable of registering the maximum gusts possible during the passage of these storms. Two instruments designed to register gusts up to 200 miles per hour were therefore obtained for the Observatory and Victoria Peak stations.
The instrument for the latter station was temporarily installed in the south-eastern corner of the Royal Observatory on 24th September, the head being 35 feet above the roof; the Beckley anemograph was dismantled on 1st October and the Dines on 4th October in order that a larger recording room could be erected upon the roof. This room was completed on 21st November and both old and new Dines recorders installed therein, together with the original Baxendell apparatus for recording wind direction which had been discarded in 1912. Either pressure recorder may now be utilised by means of suitable two-way cocks. The original Dines head is retained pending the arrival of one of modern type from England. At the end of the year the Victoria Peak instrument was still in its temporary position, and the adapted observatory instrument occupied the former position of the Beckley, the head being 40 feet above the roof.
II. METEOROLOGICAL OBSERVATIONS.
2.
Automatic records of the temperature of the air and evaporation were obtained with the resistance thermometers and thread recorder. Direction and velocity of the wind were recorded with Beckley and Dines-Baxendell anemographs, rainfall by a Casella pluviograph, sunshine by a Campbell-Stokes universal recorder and barometric pressure by a Marvin barograph. Eye observations of barometric pressure, temperature and cloud were made hourly, and of the direction of cloud motion every three hours. Observations of pilot balloons were made with a Watts 14-inch prismatic theodolite at 9 a.m. and 3 p.m. when conditions were favourable.
3. The principal features of the weather in 1938 were:—
(a) a great deficiency of rainfall, the year being the driest since 1895. The total rainfall for the year amounted to only 55.35 inches against a normal of 85.16 inches, rainfall being below normal in every month of the year except February, March and October.
(b) the prevalence of very warm sunny weather in April and June. In April the duration of sunshine was the highest on record and the temperature was well above the average, while in June both the duration of sunshine and the mean temperature were the highest on record.
(c) the unusually early typhoon of May 3rd-4th. The typhoon passed within 100 miles to the south-east of Hong Kong at midnight. During its passage the barometer fell to 29.36 inches (reduced to m.s.l.), which is the lowest pressure ever recorded in May. Although the wind never reached gale force in the harbour, the maximum gust of 63 m.p.h. is also a record for the month.
(d) an exceptional immunity from typhoon gales.
The only occasion on which the wind velocity exceeded 60 m.p.h. in a gust was during the May typhoon mentioned above. The local typhoon signals were displayed for only 63 hours during the year. The shortest periods during which they were displayed in previous years were 68 hours in 1928 and 74 hours in 1929.
4. The tracks of 24 typhoons which occurred in the Far East in 1938 are given in plates which will be included with the Meteorological Results for 1938, now in the press.
The following tables give summaries of the meteorological data published monthly in the Government Gazette during the year:—