James P. Terry Geography Department National University of Singapore Gennady Gienko Division of Geography The University of the South Pacific Locations of tropical cyclogenesis and decay in the South Pacific over the period of satellite record Cyclone Zoe, December 2002 minimum pressure: 890 hPa Niue hospital Cyclone Heta, January 2004 Lau Islands, Fiji Cyclone Ami, January 2003 Intense rainfall and river flood responses Ngalimbiu River, Honiara, Solomon Islands Wave damage Santo Island, Vanuatu Coral reef destruction 1-week post-Cyclone Kina 1993 Ovalau Island Fiji Nukunonu Atoll, Tokelau Cyclone Percy, 2005 Storm surge Beach erosion Beachrock exposure Rampart formation, subsequent migration and island nourishment Funafuti Atoll Tuvalu Regional Specialized Meteorological Centre, Nadi Equator Cyclogenesis: Often embedded within existing low pressure areas e.g. the South Pacific Convergence Zone Four stages in typical lifespan Abbreviated life cycle of Cyclone Paula, April 2000 1. Formative stage: 11 April 2. Immature stage: 14 April 3. Mature stage (920 hPa): 15 April 4. Decay stage: 20 April Plotting storm tracks 6-hourly fixes indicate direction and speed Problems Defining cyclone phase within storm lifespan Bias in defining end of tracks Effects of improved tracking technology Filtering Australian storms Matching FMS and NZMS data 1990s End of tracks? Cyclone Tracks 1990's Sin 1.009388 - 1.080000 1.080001 - 2.200000 2.200001 - 20.000000 Analysis of cyclogenesis positions and track shapes Cyclone distribution and El Niño effects 5 ENSO 10 influence R2 = 0.471 on start position average season - S) o 15 20 -30 -20 -10 0 10 20 Cyclogenesis latitude ( latitude Cyclogenesis SOI - wet season average 200 190 E) - season average - season E) o 180 R2 = 0.171 170 Cyclogenesis longitude ( longitude Cyclogenesis 160 Identifying spatio-temporal patterns 5 o S) Cyclogenesis 10 Position 15 Cyclogenesis20 Latitude ( 25 1970 240 1971 1972 o E) 1973 220 1974 1975 1976 1977 200 NE 1978 shift 1979 1980 180 1981 1982 160 1983 1984 Cyclogenesis Longitude ( 1985 140 1986 1987 120 1988 1989 1990 1991 1992 1993 1994 19951996 1997 1998 1999 2000 2001 2002 shift SE 2003 2004 2005 2006 2007 2008.