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Cyclone Mala was the strongest tropical cyclone of the 2006 North Indian Ocean cyclone season.〔 In mid-April, an area of disturbed weather formed over the southern Bay of Bengal and nearby Andaman Sea. Over a period of several days, the system became increasingly organized and was classified as a depression on April 24. Situated within a region of weak steering currents, the storm slowly intensified as it drifted in a general northward direction. It attained gale-force winds and was named ''Mala'' the next day. Conditions for strengthening improved markedly on April 27 and Mala subsequently underwent rapid intensification which culminated in the cyclone attaining its peak. Early on April 28, the cyclone had estimated winds of 185 km/h (115 mph). The Joint Typhoon Warning Center considered Mala to have been slightly stronger, classifying it as a Category 4-equivalent cyclone. Steady weakening ensued thereafter and the storm made landfall in Myanmar's Rakhine State on April 29. Rapid dissipation took place once onshore and Mala was last noted early the next morning. In contrast to Mala's intensity, damage was relatively minimal across Myanmar due to adequate early warnings, while timely and effective evacuations minimized loss of life along the coast. The greatest damage resulted from a thunderstorm near Yangon on April 28 that spawned a possible tornado in an industrial zone. A total of 586 homes were damaged there. Just outside the city in the Hinthada District, a flash flood killed at least 18 people. Overall, the storm claimed 37 lives in the country and left US$6.7 million in damage. In the wake of Mala, the Red Cross distributed relief aid to affected residents while local officials set up shelters to house those left homeless. Government and social organizations donated 5.4 million kyat (US$4,320) in cash to survivors in the Ayeyarwady Region. ==Meteorological history== In mid- to late-April, a pulse in the Madden–Julian oscillation, coupled with a Kelvin wave, (which later contributed to the formation of Typhoon Chanchu in the western Pacific) enhanced convective activity over the Bay of Bengal. By April 22, a trough developed along an axis from the southern Bay of Bengal eastward to the Andaman Sea. The Joint Typhoon Warning Center (JTWC) began monitoring the system for potential tropical cyclogenesis the following day. By 0600 UTC on April 24, an area of low pressure formed southeast of the Andaman Islands and the India Meteorological Department (IMD) began monitoring the disturbance. Quickly organizing, the low developed into a tropical depression later on April 24 and the JTWC began writing full advisories on the cyclone without issuing a Tropical Cyclone Formation Alert.〔 Organization slowed thereafter due to moderate wind shear,〔 but continued at a near-climatological rate as upper-level outflow allowed for continued convective development. Early on April 25, the JTWC estimated the system to have attained gale-force winds.〔 The IMD followed suit later that day and subsequently assigned it the name ''Mala''. Weak steering currents prompted slow and erratic movement with an overall northward trajectory.〔 Forecasters at this time anticipated little intensification as the system was expected to move into a region of higher shear. However, on April 27, the system moved under a subtropical ridge and conditions quickly became favorable for intensification. The presence of the ridge greatly enhanced the outflow over the cyclone and an eye developed by 1200 UTC.〔 By this time, both the JTWC and IMD estimated Mala to have attained hurricane-force winds with the latter classifying it as a ''very severe cyclonic storm''.〔〔 The previously weak steering currents became more established as well, with the storm now tracking northeast toward Myanmar through a weakness in a ridge over Southeast Asia.〔 Situated in an area with sea surface temperatures of , the cyclone was able to undergo rapid intensification as wind shear abruptly diminished.〔 The IMD estimated Mala to have reached its peak intensity at 0900 UTC on April 28 with winds of 185 km/h (115 mph) and a barometric pressure of 954 mbar (hPa; 28.17 inHg). Using the Dvorak technique, a method of determining a tropical cyclone's strength via satellite imagery, the agency gave Mala a rating of T#5.5 which yields an intensity of 189 km/h (117 mph).〔 The JTWC estimated Mala to have been a stronger system, with peak winds of 220 km/h (140 mph) and a pressure of 922 mb (hPa; 27.23 inHg) — equivalent to a Category 4 hurricane on the Saffir–Simpson hurricane wind scale.〔 Their Dvorak values peaked at T#6.5 or 235 km/h (146 mph). As the powerful storm approached Myanmar, the combined effects of increasing wind shear and land interaction soon took their toll on Mala. At 0700 UTC on April 29, Mala made landfall just south of Thandwe in Myanmar's Rakhine State as a very severe cyclonic storm.〔 The JTWC estimated winds at this time to have been 165 km/h (105 mph).〔 Rapid weakening ensued once the cyclone moved onshore. Within 12 hours of landfall, Mala weakened to a deep depression and was last noted as a dissipating system earl on April 30.〔 Sea surface temperatures in the wake of Cyclone Mala decreased up to 4–5°C (7–9°F) due to upwelling. From April 28–29, the low-level inflow associated affected much of the northern Bay of Bengal and resulted in northwesterly winds as far away as Hyderabad, India. These winds brought dry, dust filled air over the bay with mean particulate-matter doubling over the region. 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 Mala」の詳細全文を読む スポンサード リンク
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