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Typhoon Chan-hom, known in the Philippines as Typhoon Falcon, was a large tropical cyclone which affected Guam, the Northern Mariana Islands, the Ryukyu Islands, China and Korea in July 2015. The ninth named storm of the annual typhoon season, Chan-hom was first discovered as a weak tropical disturbance embedded within active Intertropical Convergence Zone in late-June. ==Meteorological history== On June 25, the Joint Typhoon Warning Center (JTWC) began monitoring a weak area of low pressure accompanied by intermittent bursts of convection —shower and thunderstorm activity— about 345 km (215 mi) south-southeast of Pohnpei in the Federated States of Micronesia. Drifting generally northward, the disturbance slowly organized within a region of low to moderate wind shear and favorable outflow aloft. Additionally, the circulation itself was being enhanced by a surge of westerly winds to the south. Following further organization, the JTWC issued a Tropical Cyclone Formation Alert for the low at 22:30 UTC on June 29 with the system located about 345 km (215 mi) northeast of Pohnpei. Hours later at 00:00 UTC on June 30, the Japan Meteorological Agency (JMA) classified the system as a tropical depression. Convection steadily deepened over the center throughout the day and banding features began consolidating around the periphery. Twelve hours after being declared a depression, the JMA upgraded the cyclone to a tropical storm and assigned it the name ''Chan-hom''. The JTWC assessed Chan-hom to be slightly weaker at this time, initiating it as a tropical depression.〔 Situated along the southern periphery of a subtropical ridge, Chan-hom moved steadily to the west.〔 Despite moderate wind shear, sufficient upper-level ventilation allowed for growth of the cyclone. This shear kept the circulation center slightly displaced from the deepest convection for much of July 1. Early on July 2, the large circulation of Chan-hom absorbed that of a smaller disturbance to its southeast. A slight adjustment in track to the west-southwest occurred on this day. Dvorak satellite classifications indicated that the system reached typhoon intensity following an expansion of the central dense overcast; accordingly, both the JTWC and JMA classified Chan-hom as such by 15:00 UTC. Shortly thereafter, strong wind shear stemming from a Tropical Upper Tropospheric Trough (TUTT) cell to the northeast dramatically weakened the storm. Convection was stripped away from Chan-hom's center and the storm's forward motion abruptly slowed. Alongside the shear, subsidence over the cyclone, a trough to the north, and a remnant vortex to the northeast all served to suppress convection.〔 By 12:00 UTC on July 3, Chan-hom had weakened to a tropical storm with winds of 85 km/h (50 mph). Coinciding with Chan-hom's abrupt collapse on July 3, the system turned northeast as it entered a weakness in the ridge previously steering it west.〔 Later that day, the broad circulation turned north-northwest. Wind shear began to abate early on July 4 as the aforementioned TUTT cell retreated to the north and the subtropical ridge steadily re-established itself. Owing to the lessened shear, convection started redeveloping over the tropical storm. Late on July 4 into July 5, the center of Chan-hom skirted the southern coast of Rota in the Mariana Islands. While near the island, Chan-hom executed an unusual counter-clockwise loop owing to interaction with a monsoon trough. Once clear of the Mariana Islands, steady development ensued owing to low wind shear and good outflow. Late on July 6, Chan-hom regained typhoon intensity owing to a burst in central convection. Microwave satellite imagery indicated the formation of an eye as convection deepened and banding features tightened around the circulation. On July 7, the typhoon entered the Philippine area of Responsibility and was assigned the local name ''Falcon''. Chan-hom's eye briefly improved in structure before entering a state of flux and collapsing later that day; convection on the northern side of the storm diminished simultaneously. The 65 km (40 mi) wide eye soon re-established itself and slowly contracted to a diameter of 40 km (25 mi) by July 8. A large storm, gale-force winds extended 445 km (275 mi) from Chan-hom's center on July 9. Late on July 9 into July 10, Chan-hom passed between the Japanese islands of Okinawa and Miyako-jima. The typhoon reached its peak strength during this time with estimated winds of 165 km/h (105 mph) and a barometric pressure of 935 mbar (hPa; 27.61 inHg). Featuring multiple intense feeder bands and a well-defined 27 km (17 mi) eye, the JTWC assessed Chan-hom to have peaked as a Category 4-equivalent typhoon on the Saffir–Simpson hurricane wind scale with one-minute sustained winds of 220 km/h (140 mph). An eyewall replacement cycle and weakening convection along the northern side resulted in steady weakening starting on July 10. Increasing wind shear prevented the system from reorganizing as it neared East China. Early on July 11, the typhoon reached the southwestern edge of the subtropical ridge and began turning to the north and later north-northeast. Chan-hom made landfall in Zhoushan, Zhejiang, or roughly 140 km (80 mi) south-southeast of Shanghai, around 08:40 UTC. The JMA assessed the storm to have had winds of 140 km/h (85 mph) while the JTWC estimated one-minute sustained winds at 155 km/h (100 mph).〔 Based on the JTWC estimate, Chan-hom was the strongest typhoon to pass within 160 km (100 mi) of Shanghai in at least 35 years.〔 Thereafter the storm accelerated north-northeast and moved over the cool waters of the Yellow Sea, prompting further degradation of its structure. Chan-hom weakened below typhoon-force around 18:00 UTC. The system's low-level center completely exposed on July 12 as it approached the Korean Peninsula. Between 15:00 and 18:00 UTC, Chan-hom moved ashore over South Hwanghae Province, North Korea, with winds of 95 km/h (60 mph). By 00:00 UTC on July 13 the system transitioned into an extratropical cyclone while retaining gale-force winds. 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「Typhoon Chan-hom (2015)」の詳細全文を読む スポンサード リンク
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