Hong Kong Observatory

The Hong Kong Observatory was established in 1883, mainly to provide a time service and weather information for the safe navigation of ships. Since then, it has evolved in line with community needs, providing services in weather forecasting, climatology, hydrometeorology, physical oceanography and radiation monitoring and assessment. The Observatory also administers the official time standard for Hong Kong, provides astronomical information, maintains a seismological monitoring network and operates the tsunami warning system in Hong Kong.

The Observatory issues weather forecasts and warnings of hazardous weather to the public, mariners and the aviation community as well as special users such as container terminals and transport operators.

Whenever Hong Kong is threatened by tropical cyclones, warnings are disseminated through the mass media. A colour-coded rainstorm warning system warns people of heavy rain. The Observatory also issues warnings on thunderstorms, landslips, fire danger, strong monsoon, cold and very hot weather and frost. An advisory service on the ultraviolet (UV) index is also provided. In 2005, the thunderstorm warning service was strengthened by additional lightning information generated by a newly installed lightning location system. A service to alert container terminal operators and related sectors to the occurrence of severe gusts was also introduced.

The Observatory exchanges weather observations and forecasts with the rest of the world under the framework of the World Meteorological Organisation. Weather radar images and observations of automatic weather stations are exchanged with the meteorological authorities of Guangdong and Macao. Weather is also monitored using weather buoys, an upper-air sounding system and wind profilers. These observation systems are augmented by observations from aircraft and Voluntary Observing Ships.

Objective guidance for the issuance of rainstorm and landslip warnings is provided by a computer-based nowcasting system developed by the Observatory itself. This system automatically analyses radar and raingauge data and forecasts the rainfall distribution in the territory within a few hours.

High-resolution numerical weather prediction models operated by the Observatory as well as those of meteorological centres overseas also provides objective guidance for the formulation of weather forecasts up to seven days ahead.

The Observatory's meteorologists host regular TV and radio weather programmes and conduct media briefings in the event of adverse weather. Weather information is also disseminated through the Observatory's website and its automatic Dial-a-Weather System. In 2005, the website was enhanced to include real-time weather images of popular tourist spots, more weather charts generated by the Observatory's numerical model and a wider range of satellite images. The Observatory's website continues to be one of the most popular government websites with about 520 million page hits in 2005, an increase of over 40 per cent compared with 2004.

The Observatory's outreach programme to promote preparedness against hazardous weather was expanded during the year, with new elements like talks to employees in weather-sensitive industries and campaigns run in collaboration with non-governmental organisations for the general public. It also joined forces with Radio Television Hong Kong to produce an award-winning eight-episode TV series, Meteorology Series III, on preparedness for natural disasters.

The Observatory's Airport Meteorological Office is responsible for the provision of weather services at the Hong Kong International Airport and for civil aviation for a designated airspace over the northern part of the South China Sea. In 2005, windshear alerts based on the infrared Doppler Light Detection and Ranging (LIDAR) system were automatically generated using techniques and software developed by the Observatory, making the alerts more timely and effective.

In November, the Observatory hosted a World Meteorological Organisation Seminar on Quality Management in the Provision of Meteorological Services to Aviation for 37 countries and territories in the Asia-Pacific region. The Observatory experts who lectured at the seminar used as illustration the ISO 9001 certified weather service which the Observatory provides to the aviation community at the airport.

Radiation Measurement and Assessment

The Observatory operates a network of 10 radiation monitoring stations to continuously monitor radiation levels in Hong Kong. Samples of air, water, soil and food are collected and measured for radiation regularly.

In the event of a nuclear emergency, the Observatory will immediately intensify radiation monitoring, assess the radiological consequences and provide technical advice to the relevant policy bureaux on the appropriate protective action to take.

Climatological, Oceanographic and Geophysical Services

The Hong Kong Observatory provides climatological information to meet the needs of a wide range of users and activities from recreation through to engineering design, environmental impact analysis and litigation. It also provides short-range climate forecasts and carries out studies on climate change and the impact of weather and climate on health.

In August, the Observatory announced the results of a study on the projected changes in Hong Kong's rainfall in the 21st century. At the request of the World Meteorological Organisation, the Observatory produced a report on the relationship between the weather and Severe Acute Respiratory Syndrome (SARS) and avian flu for consideration by its executive council.

The Observatory produces an annual tide table for Hong Kong. It also provides estimates of the magnitude of extreme storm surges and advice on oceanographic matters to other government departments and the engineering community.

Earthquake activities in the vicinity of Hong Kong are monitored via a network of eight short-period seismograph stations. Long-period seismographs at the Observatory's headquarters detect tremors worldwide and information on significant tremors is made public through the media. Following the disastrous Indian Ocean tsunami on December 26, 2004, the Observatory introduced tsunami bulletins, in addition to warnings, to inform the public of any tsunami that may reach Hong Kong, irrespective of its height, in order to meet the public's need for more information on tsunamis and to maintain public awareness.

The Hong Kong Time Standard is provided by a caesium beam atomic clock which is accurate to within fractions of a microsecond. The Observatory contributes to the determination of Coordinated Universal Time (UTC) by supplying signals of its atomic clock to the Bureau International des Poids et Mesures (BIPM) in France. A six-pip time signal is sent to Radio Television Hong Kong for broadcast at quarter-hour intervals. A time checking service is also available to the public through the Observatory's Dial-a-Weather System as well as through the internet. The Internet Network Time Service handled about 355 million checks in 2005, a rise of about 22 per cent compared with the previous year.