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The Hong Kong Observatory (HKO) will start issuing seasonal forecasts in early March, 2006.
Assistant Director of the Hong Kong Observatory Mr K H Yeung and Director of the Experimental Climate Prediction Centre (ECPC) of the University of California at San Diego, Dr John Roads jointly briefed the media on the seasonal forecasts this afternoon (February 7).
Dr Roads is a pioneer in short range climate forecasting. He obtained his Ph.D. from the Massachusetts Institute of Technology, studying under Professor Edward Lorenz who is one of the founders of chaos theory. Dr Roads has authored or co-authored more than 100 scientific publications.
Mr Yeung said that seasonal forecasts referred to forecasts of the average weather in the coming month, year, or season. For instance, a forecast could be for a warmer than average summer, or a colder than average winter. These forecasts were useful for planning activities which were influenced by the weather or the climate. "They can be used to assess the demand for soft drinks in the summer or for warm clothing in the winter, and to adjust the production or inventory levels accordingly. The Chicago Mercantile exchange in the United States even offers weather futures," Mr Yeung said.
He said the seasonal forecasts to be issued would be on the average temperature and the total rainfall in the coming three months, and would be issued in March, June, September and December via the Observatory's website. These forecasts will be expressed in terms of "above normal", "near normal" and "below normal" temperature or rainfall. The primary tool for producing the forecasts is a regional climate model adapted from ECPC. Model-generated forecast maps will also be displayed on the HKO website. Outputs of climate models from other climate centres will be taken into consideration in the formulation of the seasonal forecasts.
Mr Yeung explained that climate models were not too different from the numerical weather prediction models. In both cases, computers are used to simulate future weather changes. With the present state of technology, the accuracy of climate models is not yet as good as that of numerical weather prediction models. That is why the Observatory is only issuing the seasonal forecasts on an experimental basis. This will be included as part of the regular forecasting service later when the technology has gained more maturity. This is the practice adopted by other climate centres.
Dr Roads said that currently most centres used global climate models to produce seasonal forecasts. ECPC was one of the few centres to have developed regional climate models. He explained that while global models could cover a larger area, their resolution was relatively low. On the other hand, regional models covered smaller areas, but had higher resolution. Hong Kong is located in an area of complex terrain. It is appropriate that the Observatory has selected to use a regional model for its seasonal forecasts.
Dr Roads added that he was very happy the Hong Kong Observatory had adapted ECPC's regional model. He expects that more and more centres will be utilising this model or this type of model to produce seasonal forecasts.
Mr Yeung pointed out that proper use of seasonally forecasts required experience. He encouraged those in weather-sensitive businesses as well as the community at large to try to make use of the seasonal forecasts, gaining experience in the process so that they could use them more effectively in the future.
The websites for the Observatory's seasonal forecasts are http://www.weather.gov.hk/wxinfo/season/seasonc.htm (Chinese), and http://www.weather.gov.hk/wxinfo/season/season.htm (English).
Ends/Tuesday, February 7, 2006
Issued at HKT 15:16
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