The annual rainfall in Hong Kong, under the influence of global warming, would increase at a rate of about 1 percent per decade in the next 100 years, according to the latest study.

The Hong Kong Observatory announced Friday the results of its recent study on the projected change in Hong Kong's rainfall in the 21st century.

Projections of future rainfall changes in Hong Kong were made by the Hong Kong Observatory using the results of simulations made by global climate models under the various emission scenarios together with observed rainfall in Hong Kong and the southern and central parts of the Chinese mainland, through a technique called statistical downscaling.

Under the anticipated increasing rainfall trend, in the last 10years of this century, 2090 to 2099, the average annual rainfall at the Hong Kong Observatory Headquarters would be about 2,430 millimeters (mm), or 216 mm more than the 1961-1990 average of 2,214 mm.

According to Acting Director of the Hong Kong Observatory Yeung Kai-hing, in the 21st century, the number of days with heavy rain is also likely to increase.

He said that from the 30-year period 1961-1990 to the last 30 years of this century, 2070-2099, the number of days in a year with hourly rainfall exceeding 30 mm will increase from five and a half to six and a half.

According to information from the Hong Kong Observatory, the highest annual rainfall of 3,343 mm was recorded in 1997, a year in which rainstorms triggered severe flooding and numerous landslides in Hong Kong. Over 70 mm of rainfall was recorded within one hour was recorded on many occasions.

The lowest annual rainfall of 901 mm was recorded in 1963. Water rationing was implemented that year, with water supplied to the public once every four days.

(Xinhua News Agency August 27, 2005)