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Severe Tropical Cyclone Beni was an intense tropical cyclone that affected four countries, on its 18-day journey across the South Pacific Ocean during January and February 2003. The system originally developed during 19 January as a weak tropical disturbance within the monsoon trough, to the northeast of the Santa Cruz Islands. Over the next few days the system gradually developed further before it was classified as a tropical cyclone and named Beni during 24 January. Originally, the storm moved slowly towards the west. Initially moving towards the west, the cyclone then made a clockwise loop, and turned south. Beni entered more conductive conditions and began to strengthen while moving southeast. After attaining winds of hurricane-force, Beni strengthened rather quickly. Traveling between Vanuatu and New Caledonia, Beni reached its peak intensity on January 29 with winds of 125 mph (205 km/h 10-minute sustained), and a peak pressure of before rapidly weakening. The cyclone made its closest approach to the island of New Caledonia on January 30; shortly after that, Beni weakened into a tropical depression. In the Coral Sea, however, the storm once again entered more favorable conditions and it briefly re-intensified into. However, this trend was short-lived; wind shear took its toll on the cyclone, weakening it back down to a tropical depression. The remnants of Beni proceeded to make landfall near Mackay, Queensland and produce heavy rain over much of the drought stricken state of Queensland until finally dissipating on February 5. The cyclone caused a food shortage and flooded portions of the Solomon Islands. Across the island group, about 2,000 people took shelter, some in caves. In addition, the storm brought storm surge and beach erosion to Vanuatu. New Caledonia faced power outages and heavy rains. In Queensland, Beni was responsible severe flooding. Two communities were isolated during the storm; a total of 160 people were also cut off by floodwater. The water level of one dam increased from 0.5% to 81%. The cyclone's heavy rains helped ease drought problems in Queensland; in fact, water reserves replenished five years worth of supply in one location. In all, one death was reported in Queensland and damages totaled to A$10 million (US$6 million, 2003 USD) in Queensland and US$1 million (A$2 million) in Vanuatu. ==Meteorological history== Late on 19 January the Fiji Meteorological Service's Regional Specialized Meteorological Center in Nadi, Fiji (RSMC Nadi) started to monitor a tropical disturbance, that had developed within the monsoon trough to the northeast of the Santa Cruz Islands. Over the next couple of days the disturbance developed into a tropical depression as it moved towards the west-southwest, within an area of favourable conditions for further development including low vertical wind shear and sea-surface temperatures of about .〔 As the system moved near the Solomon Island of San Cristóbal during 22 February, further development of the system had become suppressed by strengthening wind shear that exposed the systems low level circulation.〔 During 24 February as the system moved beneath an upper level ridge of high pressure, the wind shear abated and convection developed over the systems consolidating low level circulation.〔 As a result, the United States Joint Typhoon Warning Center issued a Tropical Cyclone Formation Alert on the system later that day, before RSMC Nadi reported that the depression had developed into a category one tropical cyclone on the Australian tropical cyclone scale and named it Beni early on 24 January.〔〔 At around this time the JTWC initiated advisories on the system and designated it as Tropical Cyclone 12P, while it was located about to the south of the Solomon Island Rennell.〔 After being named Beni executed a small clockwise loop for two days to the southeast of Rennell, partially as a result of a strong surface ridge of high pressure to the south of the low level circulation center.〔 Environmental conditions surrounding the system also fluctuated during 25 January, as a result of Beni's position to the north of the strongly diffluent flow on the northern side of the upper-level ridge axis.〔 As a result, the systems low level circulation center became partially exposed with deep convection located to the west of the system before Beni's low level circulation slipped back under the convection during 26 January, with spiral bands wrapping tightly around the centre.〔〔 As a result, RSMC Nadi reported that the system had developed into a category 2 tropical cyclone during that day.〔〔 Over the next two days conditions continued to fluctuate with shear playing a significant role in holding back further intensification of the system.〔 Early on 28 January as a ragged eye and cloud filled eye appeared on satellite imagery, the JTWC reported that the system had become equivalent to a category 1 hurricane on the Saffir–Simpson hurricane wind scale (SSHWS).〔 When the data was reanalyzed, RSMC Nadi reported that Beni had become a category 3 severe tropical cyclone at this time, however, operationally it wasn't declared a category 3 severe tropical cyclone for another 18 hours.〔〔 Throughout 28 January Beni continued to intensify before the JTWC reported early the next day that the system had peaked, with 1-minute sustained wind speeds of 230 km/h (145 mph) which made it equivalent to a category 4 hurricane on the SSHS.〔 Later that day RSMC Nadi reported that Beni had explosively developed and peaked as a Category 5 severe tropical cyclone on the Australian scale, with 10-minute sustained winds of .〔〔 At this time the system was moving ot the southeast and was located about to the west of Port Vila, Vanuatu.〔 After peaking in intensity Beni subsequently started to weaken as a trough of low pressure increased vertical wind shear over the system, while an upper level low started to develop to the west of New Caledonia.〔〔 However, a strengthening ridge slowed Beni down and allowed the cyclone to move towards the south and then southwest, moving it away from Vanuatu. Rapid dissipating due to wind shear, the cyclone's central dense overcast was soon completely separated from Beni's center of circulation. On 30 January, the storm passed south of New Caledonia and even closer to the ''commune'' of L'Île-des-Pins, but by this time, RSMC Nadi reported that Cyclone Beni was only a marginal Category 1 system with winds of 40 mph (65 km/h) and a pressure of . The system was further downgraded into a tropical depression the same day while located southwest of New Caledonia. The depression continued to move towards the west, and subsequently northwest, across the Coral Sea, and on 1 February, the depression crossed 160°E and moved into the Australian region. In an area of once again increasing sea surface temperatures and warm air, convection developed over the center. TCWC Brisbane reported that the system was once again briefly upgraded into tropical cyclone status. At this time the pressure of the cyclone was . However, vertical wind shear once again took its toll on Beni, and the circulation center decoupled from thd deep convection and the storm's strongest winds. Consequently, Beni was once again downgraded into a depression, just 12 hours after its re-classification as a tropical cyclone. The remnant low of Severe Tropical Cyclone Beni made landfall near Mackay on 5 February. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cyclone Beni」の詳細全文を読む スポンサード リンク
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