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本文以赤道东太平洋海温作为主导因子,分析其与东亚温带气旋的关系。得出:高海温多气旋,低海温少气旋的对应关系较为明显。并进一步对不符合这种主要关系的年份从环流型。下垫面海温等作了分类鉴别分析。 相似文献
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9711号北上台风演变及暴雨过程的位涡诊断分析 总被引:6,自引:2,他引:6
通过对 971 1号台风登陆北上穿过山东造成山东特大暴雨过程的湿位涡的分析 ,并从湿位涡的角度研究了台风演变及山东特大暴雨的形成机制 ,揭示了冷空气在台风演变及暴雨过程中的重要作用。结果表明 :倾斜涡度发展是暴雨产生和台风加强的重要机制之一 ,暴雨产生在 θe线陡立密集区内 ;湿位涡在这次暴雨过程中对流层低层具有 MPV1 <0 ,MPV2 >0的特征 ,此次暴雨产生在负的MPV1等值线密集区中 ;对流层上部及平流层下部高位涡的下传使得低层斜压性增大 ,引起低层的对流稳定度减小 ,促使气旋性涡度发展 ,有利于位势不稳定能量的释放 ,使得暴雨增幅 ,导致台风的加强并演变为温带气旋。 相似文献
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本文用耗散结构理论推导出南海热带气旋的移动公式,通过实际应用和实例检验,证明它对估计南海热带气旋路径演变有一定的实用价值。 相似文献
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南极普里兹湾气旋的生消发展 总被引:3,自引:4,他引:3
利用1989~2000年现场观测的气象资料,特别是自1997年以来在南极考察船上接收的NOAA卫星极轨高分辨的卫星云图,研究了普里兹湾气旋的生消发展;提出了夏季绕极气旋进入普里兹湾内也会发展加强,在湾内东风带里也能生成气旋的新观点,修正了普里兹湾仅是气旋墓地的不全面说法,从而进一步完善了南极西风带绕极气旋和东风带上气旋生消发展的理论;研究了普里兹湾冰-气-海相互作用的机理,解释了气旋发生、发展的物理过程.用整体动力学输送法计算了进入普里兹湾980205号绕极气旋爆发性发展的能量交换,指出气旋在超过冰坝进入冰间湖可以获得巨大的热量,使气旋迅速发展成为具有南极特色的强风暴,风力达12级以上,平均风速为38m/s;瞬时最大风速达100m/s. 相似文献
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Marta Sebastin Javier Arístegui María F. Montero Jose Escanez F. Xavier Niell 《Progress in Oceanography》2004,62(2-4):131
The enzymatic activity of alkaline phosphatase (APA) was studied in the transition zone between the African upwelling system and the open ocean waters of the Canary Islands region. This region is recurrently dominated by the presence of upwelling filaments that may transport nutrient-enriched waters out into the open ocean before nutrients become exhausted by plankton. Turnover rates by APA were generally low in the whole region, but detectable in all the measurements carried out. On average, turnover rates were higher in the upwelling stations, and APA in those waters seemed to be mainly generated by heterotrophic bacteria to supply easily assimilable organic C. APA outside the upwelling area showed an inverse hyperbolic relationship with increasing phosphate, suggesting the presence of both constitutive and Pi-inducible APA. In these offshore waters, a threshold of 0.1 μM of phosphate could be defined for the regulatory function of Pi on APA. Thus, APA in nutrient-poor waters seemed to be induced to compensate for Pi-deficiency. Turnover rates in the filaments showed basal (probably constitutive) levels, whereas they increased in the surrounding waters, where phosphate concentration presumably did not satisfy plankton P-demands. The fertilising effect of the filaments and associated cyclonic eddies extended to at least 175 km offshore, where basal alkaline phosphatase activities were still found. The magnitude of this effect depends probably on the intensity of upwelling events and the degree of recirculation of filament water back to the coastal jet. 相似文献
8.
Using meteorological data of field observation in 1990 - 2000, especially polar orbit high-resolution NOAA satellite cloud maps received from the Antarctic expedition vessel since 1997, the formation and development of the Prydz Bay cyclone are studied in this paper. Some new viewpoints are suggested such as: when surround-polar cyclone enters the Prydz Bay, it can also intensify and develop in summer; cyclone can also develop in the easterlies in this bay. These view points revise old uncom-plete view point that the Prydz Bay is a burial ground of cyclone, and also further consummate formation-development theory of surround-cyclone in the Antarctic westerlies and cyclone in the Antarctic easterlies. In this paper, the mechanism of ice-air-sea interaction in the Prydz Bay is studied, and the physical process of cyclone formation-development is explained. By use of wholly dynamic transportation method, an energy exchange case of a cyclone, which explosively developed after entering the Prydz Bay, is calcu 相似文献
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The shedding of mesoscale anticyclonic eddies from the Alaskan Stream and westward transport of warm water 总被引:1,自引:0,他引:1
Konstantin Rogachev Natalya Shlyk Eddy Carmack 《Deep Sea Research Part II: Topical Studies in Oceanography》2007,54(23-26):2643
The south-flowing waters of the Kamchatka and Oyashio Currents and west-flowing waters of the Alaskan Stream are key components of the western sub-Arctic Pacific circulation. We use CTD data, Argo buoys, WOCE surface drifters, and satellite-derived sea-level observations to investigate the structure and interannual changes in this system that arise from interactions among anticyclonic eddies and the mean flow. Variability in the temperature of the upstream Oyashio and Kamchatka Currents is evident by warming in mesothermal layer in 1994–2005 compared to 1990–1991. A major fraction of the water in these currents is derived directly from the Alaskan Stream. The stream also sheds large anticyclonic (Aleutian) eddies, averaging approximately 300 km in diameter with a volume transport significant in comparison with that of the Kamchatka Current itself. These eddies enclose pools of relatively warm and saline water whose temperature is typically 4 °C warmer and salinity is 0.4 greater than that of cold-core Kamchatka eddies in the same density range. Aleutian eddies drift at approximately 1.2 km d−1 and retain their distinctive warm and salty characteristics for at least 2 years. Selected westward pathways during 1990–2004 are identified. If the shorter northern route is followed, Aleutian eddies remain close to the stream and persist sufficiently long to carry warm and saline water directly to the Kamchatka Current. This was observed during 1994–1997 with substantial warming of the waters in the Kamchatka Current and upstream Oyashio. If the eddies take a more southern route they detach from the stream but can still contribute significant quantities of warm and saline water to the upstream Oyashio, as in 2004–2005. However, the eddies following this southern route may dissipate before reaching the western boundary current region. 相似文献