XN000022-1976-09-21 — Page 2

1

ANALYSIS OF LAST MONTH'S RAINFALL DATA

*****

THE ROYAL OBSERVATORY HAS CARRIED OUT A MORE COMPLETE ANALYSIS OF THE RAINFALL DATA RELATING TO TROPICAL STORM ELLEN WHICH BYPASSED HONG KONG IN THE SECOND HALF OF AUGUST,

AS A RESULT, THREE GRAPHS SHOWING THE AREA AND TIME DISTRIBUTION OF RAINFALL AND THE RAINFALL BROUGHT BY THIS AND TWO OTHER MAJOR STORMS IN THE PAST TEN YEARS HAVE BEEN

PREPARED.

J

AT THE SAME TIME. A DETAILED TECHNICAL STUDY OF THE SYNOPTIC AND DYNAMICAL ASPECTS OF THE STORM IS ALSO UNDER PREPARATION.

A SPOKESMAN FOR THE ROYAL OBSERVATORY SAID THAT THE DISASTROUS LANDSLIP AT SAU MAU PING AND THE WIDESPREAD FLOODING THAT OCCURRED IN THE WAKE OF TROPICAL STORM ELLEN LAST MONTH GAVE RISE TO PUBLIC CONCERN ABOUT THE EFFECT OF HEAVY RAIN ON SO IL SLOPES.

DURING THE PAST TWO WEEKS, HE SAID, THE ROYAL OBSERVATORY RECEIVED A NUMBER OF ENQUIRIES FROM PEOPLE CONCERNED ABOUT THE DISTRIBUTION OF THE RAINFALL BROUGHT BY TROPICAL STORM ELLEN,

ACCORDING TO THE ANALYSIS, THE SPOKESMAN SAID, MORE RA IN WAS RECORDED ON HIGH GROUND AND THE WETTEST AREA WAS LOCATED NEAR MA ON SHAN WITH A TOTAL RAINFALL OF ABOUT 700 MM.

+FROM THIS AREA, A BELT OF HEAVY RAINFALL STRETCHED SOUTHWARDS ACROSS SAU MAU PING AND THE KOWLOON BAY TO THE TYTAM RESERVOIR ON HONG KONG ISLAND, HE SAID. +THIS BELT COVERED MOST OF THE URBAN AREAS IN KOWLOON AND THE EASTERN PART OF HONG KONG ISLAND WHERE THE TOTAL RAINFALL RECORDED WAS IN EXCESS OF 550 MM.+

THE SPOKESMAN POINTED OUT THAT MUCH LESS RAIN FELL OVER THE NORTHWESTERN PART OF THE NEW TERRITORIES AND TO THE EAST OF HONG KONG ISLAND.

+THE THREE-DAY RAINFALL (AUGUST 24-26) WAS ONLY 251 MM AT TATHONG POINT LIGHTHOUSE AND 266.1 MM AT NIM WAN TO THE NORTHWEST OF CASTLE PEAK. THESE REPRESENT LESS THAN 40 PER CENT OF THE MAXIMUM RAINFALL RECORDED NEAR MA ON SHAN,+ HE ADDED.

THE SPOKESMAN COMPARED THE MAXIMUM AMOUNTS OF RAINFALL FOR VARIOUS DURATIONS WITH THOSE RAINSTORMS IN 1966 AND 1972.

FOR DURATIONS OF 12 HOURS AND OVER, HE SAID, THE MAXIMUM RAINFALL AMOUNTS RECORDED DURING TROPICAL STORM ELLEN WERE GREATER THAN THOSE IN 1966 AND 1972.

HOWEVER, WHEN SHORTER DURATIONS WERE CONSIDERED, THE 1966 AND 1972 RAINSTORMS WERE CONSIDERABLY WETTER.

THE HIGHEST ONE-HOUR RAINFALL EVER RECORDED, HE POINTED OUT, OCCURRED IN 1966 WITH THE AMOUNT DOUBLE THAT OF 1976.

FOLLOWING IS A TABLE SHOWING THE MAXIMUM RAINFALL AMOUNTS RECORDED AT THE ROYAL OBSERVATORY FOR VARIOUS DURATIONS WITH THE CORRESPONDING FIGURES RECORDED DURING THE HEAVY RAINSTORMS IN 1966 AND 1972. THE HIGHEST FIGURES EVER RECORDED SINCE RECORD BEGAN IN 1884 ARE ALSO INCLUDED.