Newsletter For Hong Kong Voluntary Observing Ships No.20/ July 2004 Hong Kong Weather Services for Shipping Booklet ¡@¡@The booklet on "Hong Kong Weather Services for Shipping" prepared by the Hong Kong Observatory will be available soon. ¡@¡@The booklet puts under one cover information on the weather services provided by the Hong Kong Observatory for mariners at sea and in the harbour of Hong Kong. A summary of all weather bulletins for shipping issued by the Hong Kong Observatory and their broadcast schedules can be found in the publication. ¡@¡@Complimentary copies of the booklet will be provided to the shipmasters of the Hong Kong Voluntary Observing Ships (HKVOS) and local shipping agents. The web version of the booklet can be viewed at the following Hong Kong Observatory website: ¡@¡@http://www.hko.gov.hk/wservice/tsheet/pms/index_e.htm Forecast Weather Maps at Hong Kong Observatory Website ¡@¡@In addition to the provision of daily weather charts, the Hong Kong Observatory launches in its website forecast weather maps generated by the Observatory¡¦s high-speed computer. ¡@¡@The forecast weather maps will help the mariners to understand the trends in weather conditions over a period of two to three days in the South China Sea and the western Pacific region. ¡@¡@The forecast elements include surface air temperature, surface wind speed and wind direction, mean sea level pressure and the state of sky at various locations. The information in the map is updated twice daily. ¡@¡@The forecast weather maps can be viewed at the following website: ¡@¡@http://www.hko.gov.hk/cgi-bin/hko/nwp.pl?lang=e Five New Members of HKVOS ¡@¡@Five container ships joined the HKVOS scheme during the past year. We are very grateful to Captain Tang Yiu Tzu (M.V. OOCL Long Beach), Captain Yan Ping (M.V. OOCL Qingdao), Captain Keith Townley (M.V. Maersk Gairloch), Captain Lee Kin Hung (M.V. OOCL Rotterdam) and Captain David Roger Llewellyn (M.V. OOCL Hamburg) for their enthusiastic support to the scheme. ¡@¡@The Hong Kong Observatory currently maintains a fleet of 44 locally based merchant ships to make weather observations at sea. These weather observations provide vital information for weather analysis and are especially important for the preparation of weather forecasts and timely issuance of warnings for the sea areas. ¡@¡@Any ships calling at Hong Kong on a regular basis are welcome to join the HKVOS scheme. Please contact our Port Meteorological Officer or visit the following website for more information: ¡@¡@http://www.hko.gov.hk/wservice/tsheet/pms/images/HKVOS_recruit_e.pdf New Tropical Cyclone Names in Use ¡@¡@Since 1 January 2004, four new members have been included in the list of tropical cyclone names for the western North Pacific and the South China Sea. The new names are "Peipah" (a popular pet fish in Macau) from Macau, China, "Nuri" (a blue crowned parakeet in the Malay language) from Malaysia, "Molave" (a popular hardwood used in furniture) from the Philippines and "Matmo" (meaning heavy rain) from Guam, USA. These new names replace "Vamei", "Rusa", "Imbudo" and "Chataan" respectively. ¡@¡@The list consists of 140 tropical cyclone names contributed by 14 member countries and territories of the Typhoon Committee. According to present practice, the member countries and territories concerned may request the Typhoon Committee to delete the names of tropical cyclones that have inflicted severe damage and loss of life from the list and replace them with new ones. ¡@¡@The new list of tropical cyclone names and their meanings can be found at the following Hong Kong Observatory website: ¡@¡@http://www.hko.gov.hk/informtc/sound/tcname2004e.htm Dujuan - a Typhoon with Double Eye Walls ¡@¡@On 2 September 2003, a double-eye-walled structure of Typhoon Dujuan was observed by the Hong Kong Observatory¡¦s radar when it moved towards the South China coast. The diameters of the inner and outer eyes of Dujuan were about 20 km and 100 km respectively. ¡@¡@The eye wall is the innermost ring of convective rain band near the centre of a typhoon. It is where the most intense winds and fiercest rain occur. While most typhoons have a single eye wall, many strong and mature typhoons develop a double-eye-walled structure. In the west Pacific, development of the double-eye-walled structure was not rare. It was observed in Typhoon Kirogi and Typhoon Kai-Tai in 2000. ¡@¡@When strong typhoons show a double-eye-walled structure, they are often in the process of undergoing an "eye wall replacement cycle" where a new eye wall develops and replaces an existing one. The double-eye-walled structure usually marks the end of an episode of intensification and may last for a day or two. List of Inmarsat-C Coast Earth Stations ¡@¡@Deck officers may be aware that ship weather reports can be disseminated to a Coast Earth Station (CES) at no cost to ships by using an Inmarsat service code 41 for routing the reports to the related meteorological centre. A list of Inmarsat-C CES in different regions accepting code 41 is shown below: Atlantic Ocean Region-East Country Station name Identity code France Aussaguel 121 Germany Raisting 115 Greece Thermopylae 120 Netherlands Station 12 112 UK Goonhilly 102 USA Southbury 101 Atlantic Ocean Region-West Country Station name Identity code Netherlands Station 12 012 UK Goonhilly 002 USA Southbury 001 Indian Ocean Region Country Station name Identity code Australia Perth 322 France Aussaguel 321 Germany Raisting 333 Greece Thermopylae 305 Japan Yamaguchi 303 Netherlands Station 12 312 Singapore Sentosa 328 Pacific Ocean Region Country Station name Identity code Australia Perth 222 Japan Yamaguchi 203 Singapore Sentosa 210 USA Santa Paula 201 Summary of Tropical Cyclones over the South China Sea in 2003 ¡@¡@In 2003, eight tropical cyclones affected the South China Sea, the area bounded by 10¢XN and 25¢XN, 105¢XE and 120¢XE. This was less than the normal of 12 a year. Two of these tropical cyclones formed in the South China Sea. The other six moved into the South China Sea from the western North Pacific. A brief summary of five tropical cyclones that brought gale force wind or above to the busy shipping lanes over the South China Sea in 2003 is given below: ¡@¡@Koni developed as a tropical depression (TD) about 1 000 km east-southeast of Manila on 16 July. Koni entered the South China Sea and intensified into a tropical storm (TS) on 18 July. On 19 July, it turned to the northwest. Koni intensified further into a severe tropical storm (STS) and attained a maximum wind speed of about 100 km/h near its centre on 20 July. On 21 July, it moved towards west-northwest and traversed Hainan that night. Koni entered Beibu Wan on 22 July and then weakened into a TS after making landfall in northern Vietnam that night. Over land, Koni further weakened into a TD in the early morning of 23 July and dissipated about 100 km west of Hanoi the same day. ¡@¡@Imbudo developed as a TD about 730 km southwest of Guam on 17 July. Tracking towards the west-northwest, it intensified into a TD the same night. Imbudo became an STS on 19 July and further strengthened into a typhoon the next day with a maximum wind speed reaching about 185 km/h near its centre on 21 July. Imbudo swept through Luzon on 22 July. Imbudo entered the South China Sea on 22 July night and continued to move west-northwestwards towards the South China coast. In the morning of 24 July, it made landfall near Yangjiang of western Guangdong and then weakened into an STS. Imbudo weakened into a TS over land in the morning of 25 July and dissipated in Guangxi the same day. ¡@¡@Krovanh developed as a TD about 110 km south-southwest of Guam on 17 August. Krovanh intensified into a TS on 20 August night and further intensified into an STS the next night. It reached typhoon strength on 22 August and moved across Luzon that night. Adopting a west-northwest track, Krovanh entered the South China Sea on 23 August morning and moved across the northern part of the South China Sea the next day. After skirting the northeastern part of Hainan, Krovanh entered Beibu Wan on 25 August. Krovanh weakened into an STS in the early morning on 26 August after making landfall over northern Vietnam. It further weakened into a TS the same day and dissipated inland that night. ¡@¡@Dujuan developed as a TD about 990 km west-northwest of Guam over the Pacific in the early morning of 29 August and was slow-moving. It intensified into a TS in the early morning of 30 August and strengthened further into an STS the same day. Accelerating towards the west-northwest on 31 August, Dujuan attained typhoon strength and moved towards the seas near southern Taiwan. After crossing the seas south of Taiwan on 1 September, Dujuan headed westwards towards the South China coast. The maximum sustained wind speed near its centre reached 175 km/h. Dujuan entered the South China Sea in the early morning of 2 September and moved westwards towards the coast of Guangdong. On 2 September night, Dujuan skirted the north of Hong Kong and hit Shenzhen. It then continued to move westwards crossing Guangdong. Dujuan weakened rapidly into a TS in the morning of 3 September and became an area of low pressure over Guangxi afterward. ¡@¡@Nepartak formed as a TD about 530 km west-northwest of Yap on the night of 12 November. Tracking westwards, it intensified into a TS on 13 November. On 14 November, Nepartak moved across the central part of the Philippines and entered the South China Sea. On 15 November, it intensified into an STS and tracked northwestwards. The HKVOS ¡§OOCL Netherlands¡¨ (call sign VRVN6) reported 40 knots northerly winds about 101 km northwest of Nepartak at 0000 UTC on 17 November. Nepartak attained typhoon strength in the early morning of 18 November. It skirted western Hainan the same day and weakened gradually into an STS that night. Nepartak weakened further and became an area of low pressure over Beibu Wan on 19 November. List of tropical cyclones affecting the South China Sea in 2003 Name of tropical cyclone Formation date (day/month) Dissipation date (day/month) Maximum sustained wind speed near the centre (km/h) Minimum sea-level pressure (hPa) Severe Tropical Storm Nangka 1/6 4/6 90 985 Severe Tropical Storm Koni 16/7 22/7 100 980 Typhoon Imbudo 17/7 25/7 185 930 Tropical Storm Morakot 2/8 4/8 85 990 Typhoon Krovanh 17/8 26/8 140 960 Tropical Storm Vamco 19/8 20/8 65 992 Typhoon Dujuan 28/8 3/9 175 940 Typhoon Nepartak 12/11 19/11 130 965