THE ENVIRONMENT
essential to improving our understanding and forecasting capability of the environment, thus they need to be impeccably accurate. Faced with the challenge, the laboratory has placed strong emphasis on quality assurance. In 1996, the laboratory became the first in Hong Kong certified under ISO 9001 to provide a full spectrum of accredited tests encompassing environmental analysis.
Apart from analysing for pollution monitoring, the laboratory also serves as a referee analyst under different ordinances and regulations related to environmental protection. In 1996, over 800 samples were examined for litigation purpose in strict compliance with internationally accepted methodology.
Pollution knows no boundary, so close liaison must be maintained with peer organisations the world over. In this regard, the laboratory has established working relationships with renowned testing institutes such as the Environment Technology Centre of Canada and the China National Environmental Monitoring Centre in Beijing. It also collaborated with the Shenzhen Environmental Monitoring Station through the EPD in the Joint Deep Bay monitoring programme to address cross- border pollution issues.
Climate
Hong Kong's climate is sub-tropical, tending towards the temperate for nearly half the year. During November and December, there are pleasant breezes, plenty of sunshine and comfortable temperatures. Many people regard these as the best months of the year. January and February are cloudier, with occasional cold fronts followed by dry northerly winds. Temperatures can drop below 10 degrees Celsius in urban. areas but sub-zero temperatures and frost usually occur only on high ground and in the New Territories.
March and April can be very pleasant with occasional spells of high humidity. Fog and drizzle can sometimes disrupt air traffic and ferry services because of reduced visibility.
May to August are hot and humid with occasional showers and thunderstorms, particularly during the mornings. Afternoon temperatures often exceed 31 degrees, but at night temperatures generally remain around 26 degrees.
Hong Kong is most likely to be affected by typhoons in September, although tropical cyclones of varying strength are not unusual at any time between May and November. On average, about 31 tropical cyclones form over the western North Pacific and the China Seas every year, and about half of them reach typhoon strength with maximum winds of 118 kilometres per hour or more.
When a tropical cyclone is about 700 to 1 000 kilometres south-east of Hong Kong, the weather is usually fine and exceptionally hot, but isolated thunderstorms sometimes occur in the evenings. If the cyclone's centre comes closer to the territory, winds will increase and rain can become heavy and widespread. The heavy rain may last for a few days, and subsequent landslips and flooding sometimes cause considerably more damage than the winds.
The mean annual rainfall ranges from around 1 300 millimetres at Waglan Island to more than 3 000 millimetres around Tai Mo Shan. About 80 per cent of the rain falls between May and September. August is the wettest month, when it rains about four days out of seven with a monthly average at the Royal Observatory of 391.4
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