East Asia and Western Pacific METEOROLOGY AND CLIMATE

The digital radar at RO has been very useful for indicating the
occurrence of intense rain and is indispensible for the issuance of
landslip and flooding warnings during inclement weather. However, for
estimating quantitative rainfall and for producing objective rainfall
forecast2] r means of calibrating the radar with raingauges should be
used.
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ACKNOWLEDGEMENT
The authors wish to thank Mr. F.C. Lam for supplying programs to
extract CAPPI data, Mr. Y.C. Yeung for his help in data processing and
Mr. L.K. Yau for supplying software to plot radar/gauge time traces.
REFERENCES
1. Austin, P. M. r "Relation between measured radar reflectivity and
Surface Rainfall", Mon. Weather Rev., Vol 115, 1053-1071 (1987).
2. Lam, C.Y.,"Digital Radar Data as an Aid in Nowcasting in Hong Kong",
Proc. Nowcasting-II Symposium, Norrkoping, Sweden, 3-7 Sept. 1984.
3. Wilson, J, W. and Brandes, E. A., "Radar Measurement of Rainfall - A
Summary", Bull. Amer. Meteor. Soc., Vol 6iQ, No. 9, 1048-1058 (1979).
4. Zawadzki, I., Desrochers, C., Torlaschi, E. and Bellon, A., "A
Radar-Raingauge Comparison", Preprints, 23rd Conf. on Radar
Meteorology, Snowmass, Amer. Meteor. Soc., 121-124 (1986).
Notes for the Tables: 1) I indicates that gauges with Ra/Rg outside
2 s.d. of the Ra/Rg.for the storm, have been retained. 2) * denotes
cases with significant difference between 1 km and 3 km radar estimated
rainfall. 3) Weather is the severest weather reported during the rain
case. TS denotes thunderstorms. 4) The maximum intensity (MI) is the
average of the 10 largest rate of rainfall detected by the radar over
the area of Hong Kong during the rain case. 5) The RO gauge total is
the sum of the gauge data in the series of available 5-minute
radar/gauge pairs for the Royal Observatory (RD1) during the rain
case. It is not identical with the rainfall recorded at the Royal
Observatory for the same time period because radar data is not always
available.