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Thursday, 17th March 2011

New services

The world weeps over the tremendous loss of lives on 11 March brought by the severe earthquake off the coast of northern Japan, and in particular the killer tsunamis in its wake. We express our deepest grief and sympathize with the families and friends of those killed or injured by the catastrophe on that fateful Friday.

Immediately after the earthquake and tsunamis, Observatory colleagues issued press releases and gave press conferences to address the information needs of the public. As further threats from tsunamis ebbed, there was news of leakage of radioactivity from a Japanese nuclear power plant damaged by the tsunamis. Apart from providing the relevant radiation information in support of the Security Bureau, our colleagues also moved to immediately implement new services, to ensure that people are kept informed about the latest development on the disaster. These are elaborated as follows.

Figure 1     Mr Donald Tsang, The Chief Executive, inspects the work at the Observatory on 16 March
Figure 1      Mr Donald Tsang, The Chief Executive, inspects the work at the Observatory on 16 March

Forecast trajectory of air arriving in Hong Kong over the next 3 days

Available at the hyperlink:, the forecast trajectories tell us where the air would come from each day, over the next 3 days. Immediately after the earthquake, the trajectories indicated that the air would come from China, the Taiwan Strait or the Luzon Strait, so that the risk of radioactivity from Japan directly reaching Hong Kong was very low. By browsing at the website given above, the public will be able to assess the situation each day.

Real-time radiation data in Hong Kong

There are 10 radiation monitoring stations which continuously measure radiation levels at various places in Hong Kong. The Observatory receives the data in real-time and publishes the past day's levels every day under "Yesterday's weather" page at the Observatory website. In light of the incident in Japan, hourly radiation data from these 10 monitoring stations are now available for public viewing at the hyperlink:, for the duration of the episode. A word of caution is needed when interpreting the data: there are natural fluctuations in the radiation level, and the radiation level may rise a little when it is raining. The public should not be worried about these because they all arise from natural causes. The Observatory's current assessment is that the possibility of radioactivity from the nuclear power plant arriving in Hong Kong and bringing significant effect is extremely small. We will monitor the situation closely and update the public when necessary.

Monitoring of sand and dust

The Observatory has recently enhanced the provision to the public of meteorological information useful for the monitoring of sand and dust which may potentially affect Hong Kong. With immediate effect, the public will be able to access the relevant information, from the following website: In essence, the information includes: (a) the latest reports on dust or sand, if any, observed anywhere in east Asia; (b) satellite pictures enhanced to show delineated areas of dust or sand, if any, over the same region; and (c) forecast trajectories of air that would arrive in Hong Kong each day, over the next 3 days.

My tribute to those at the Observatory who worked so hard to make them possible.

B.Y. Lee

Last revision date: <17 Jan 2013>