Reconstruction of an 8,000-year record of typhoons in the Pearl River Estuary, China. G. Huang 1 & W.W.-S. Yim 2 1 Department of Environmental Sciences, South China University of Technology, Guangzhou, China 2 Department of Earth Sciences, The University of Hong Kong, Hong Kong SAR, China.
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G. Huang1 & W.W.-S. Yim2
1 Department of Environmental Sciences, South China University of Technology, Guangzhou, China
2 Department of Earth Sciences, The University of Hong Kong, Hong Kong SAR, China
Classification Wind speed* (km/hr) Beaufort scale.
Tropical depression 41 - 62 6 -7
Tropical storm 63 – 87 8 – 9
Severe tropical storm 88 – 117 10-11
Typhoon 118 or above 12
* Averaged over a period of 10 minutes.
A typhoon originating in the western Pacific off Luzon
Fact – Typhoon damage will increase in the future
Past record may be useful for prediction to reduce risk
Year Type of disaster Death toll .
1937 Unnamed typhoon ~11,000 (1%)
1906 Unnamed typhoon ~10,000 (3%)
1962 Typhoon Wanda 130
1971 Typhoon Rose 110
1925 Po Hing Fong landslide 73
1972 Sau Mau Ping landslide 71
1972 Mid-levels landslide 67
1960 Typhoon Mary 45
1964 Typhoon Ruby 38
1964 Typhoon Dot 26 .
(1) 1884 to 2000 – instrumental record of the Hong Kong Observatory (best from 1975 onwards because of satellites)
(2) 700 to 1883 AD – historical documentation of Guangdong
(3) 8,000 years Before Present to 700 AD – offshore boreholes and beach-dune barriers including radiocarbon and archaeological ages
Distribution of Neolithic middens in the Pearl
River Estuary showing the location of the
coastline ~6,000 years Before Present
2-dimensional model of sedimentation in the Pearl River Estuary
during typhoons. Storm deposits are identified by their foraminiferal
Cross-section across the Pearl River Estuary showing facies distribution,
radiocarbon ages and magnetic susceptibility profiles obtained in the six
Lagoon facies distribution,
Inner dune barrier
Outer dune barrier
Air photo of beach-dune barriers at Pui O, Lantau Island. The inner barrier
is younger than 2,200 years Before Present based on radiocarbon ages
Radiocarbon ages and archaeological ages of beach-dune barriers in the
vicinity of the Pearl River Estuary
Category No. of Damage No. of
I <4 moderate to minimal 149
damage; death toll <100
II 5-8 extensive damage ; death 8
toll 100 to 5,000
III >8 extreme damage; death 4
toll > 5,000 .
Plot of decadal typhoon distribution based on historical documentation
from AD 700 to 1883 and instrumental documentation from AD 1884 to
(1) Parameters of typhoon
- central pressure - closest approach
- translational speed - path
(2) Coastal parameters
- seafloor topography - coastal configuration
(3) Local factors
- river discharges - seiching
- rainfall runoff - tidal effects
- wind effects
Tracks of top 10 typhoons affecting the Pearl River Estuary from
1884-2000. Based on Hong Kong Observatory data.
Sha Tin River Estuary from
Tolo Harbour – location of worst death toll
Sha Tin – unnamed typhoon 1937
Tai Po – Typhoon Wanda 1962
Survivors of 1937 typhoon
Reclamations are prone to storm-surge flooding through the trough effect
Reclamation in Victoria Harbour
Flooding in Happy Valley Typhoon Wanda 1962
Flooding in Kwai Chung Road 1982
Frequency of typhoons in the northwestern Pacific during 1946-2000. From Huang & Yim (2001).
(1) Typhoons have occurred since ~8,000
years Before Present.
(2) Instrumental documentation provides the best record of typhoons followed in order by historical documentation, beach-dune barriers and offshore boreholes.
(3) The 5-year running mean of typhoon frequency is found to decline prior to the onset of El Niño years.
(4) Multi-decadal variability in the frequency of typhoons have been found in the northwest Pacific since 1945.
(5) Whether global warming is causing a change in frequency of typhoons in the South China sea and the northwest Pacific requires further investigation.