230976-1936-Supplementary-Wireless-transmissions-from-the-Royal-Observatory-Hong-Kong — Page 3

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4. *Shipmasters are earnestly requested to co-operate in order that the synoptics and forecasts may be as accurate as possible. Routine observations made at 6 a.m. and 2 p.m. H.K. Standard Time (2200 and 0600 G.M.T.) are specially requested, and when in the vicinity of a typhoon it is hoped that observations will be sent as often as is found convenient. In addition, invaluable assistance to aviation may be rendered by frequent communication of reports concerning visibility and state of the sky (i.e. type, amount and estimated height of cloud) during transit between Hong Kong and Shanghai, the Philippines, Hainan, Indo China, Siam and Malaya. Continuous watch is kept at Cape d' Aguilar (VPS) on 600 and on 36.23 metres from 6 a.m. to midnight. The information primarily required is :-

Ship's position (Latitude and Longitude to

Time of observation

Barometer reading (any unit)

Wind direction

Wind force

Weather

10

1- of a degree)

which may be sent in the form found most convenient, e.g. in plain language or by International Code. The following data may be added if available :-

Air temperature

Temperature of sea surface

State of sea

Direction of swell, and Visibility.

5. Any reports forwarded should be distinguished by a suitable combination of the letters a, e, m, u, signifying whether the barometer is an aneroid (a) or mercurial (m), and whether the reading is corrected (c) or uncorrected (u); thus "me" would signify "mercurial, corrected". It is of great importance that readings of the ship's barometer made in Hong Kong should be forwarded by post or messenger whenever possible. The correction determined at the Royal Observatory from these readings will always be forwarded to the master upon request. A brief explanation of the International Code is appended. Extra copies of this notification may be obtained on written or personal application to the Director, Royal Observatory, who will at all times be pleased to give every possible information to any shipmaster or officer.

International Meteorological Code.

In the International Code figures are used in groups of five, the significance of the figures depending upon the group in which they occur and their position in the group. For the purpose of radio transmission in the Far East the necessary groups are as below.

Land Stations.

Fig.

Group 1 1st

2nd

3rd

4th

5th

Index number of station or designating letters as per list.

Barometric tendency-Table IX

Past weather-Table VII

* Masters of "A" and "B" selected ships are requested to assist, if possible, without detriment to the routine prescribed by international agreement.