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By utilizing the denser upper-air observations from the Okinawa region and the Japanese islands during August 17-23, 1975, the structure of Typhoon 7507 formed in this area has been analysed. It has been indicated that the cyclonic tangential wind maximum occurred in the eastern sector of the typhoon and the strongest inflow occurred in the southern portion of the typhoon about 150 km away from the typhoon centre. There was a deep inflow layer below the 300 hPa level. The anticyclonic outflow was the strongest at 150 hPa and was located in the NE quadrant of the typhoon. The convergence mainly took place in the southern part of the typhoon, while the divergence occurred at the lower and middle levels in the northern sector of the typhoon. The pattern of vorticity and vertical motion field were characterized by the similar asymmetry. 相似文献
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This paper, the second part of further analyses of the structure of the typhoon, mainly discusses the distributions of temperature and moisture fields of typhoon No. 7507. The result has shown that the typhoon developed from the warm-core disturbance. The height of maximum warming is highest (300 to 250 hPa) during the mature stage. There is a dry layer capping the typhoon during the initial stage. Once the typhoon rapidly developed, the dry layer was destroyed. A deep saturation layer eventually occurred in the central region of the typhoon. Meanwhile, the dry air from the China main continuously intruded into the outer region in the western and northwestern parts of the typhoon.The initial eyewall of the typhoon sloped outward with increasing height, and then became nearly vertical below 12 km level. This was closely associated with convective activity. The convective instability had been mostly released during the growing stage of the typhoon and stratification rapidly tended to moist neutralization. 相似文献
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7507号台风中水汽收支的研究 总被引：10，自引：0，他引：10
本文研究了1975年7号台风的水汽收支。结果发现,对降水贡献最大的项是由辐散风造成的质量场辐合,尤其是在低层,约占总降水的70%。平流项的作用很小。垂直输送项把低层的水汽向中上层输送,增加该处的水汽累积。蒸发项对降水也起重要作用,约占总降水的13%。蒸发项为水汽水平辐合的23%。台风的主要水汽来源于台风的南边界,其次是西和东边界,这三个边界的流入层都很深厚,达到300hPa,但最强的流入在700hPa以下。在台风北边界整层为流出。对整个台风而言,由于输入的水汽量远大于流出的,从而使台风得到大量的水汽供应。 用三种方法计算的台风降水区分布都与台风的云雨区很一致,但量值有明显的差别。 相似文献
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本文是7507号台风结构进一步分析的第二部分,主要讨论台风温度场和湿度场分布。分析发现台风是从一个具有暖心的扰动发展而来,最大增温中心的高度在成熟期最高(300—250hPa)。在初期,台风上空有一个干层,一旦台风迅速增长,干层即被破坏,台风中心区出现相当深厚的饱和层,同时在台风西部和西北部不断有从大陆来的干空气侵入台风外区。台风的眼壁初期坡度较小,以后在12km以下变成垂直,这与对流活动有密切关系。对流不稳定在台风发展期已大部分释放完,很快地趋近湿中性层结。另外,水汽辐合在台风南北半部有明显不同,北半部以辐散为主,南半部以辐合为主,最强的水汽辐合在边界层中,尤其在近地面层。 相似文献
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This paper deals with the study of moisture budget of the typhoon No. 7507. The results show that the mass convergence produced by divergent wind has made the maximum contribution to precipitation, especially at the lower level, accounting for about 70% of the total precipitation, and that the advection term of water vapor is very small. The vertical flux term is to transport water vapor from the lower level to the middle and upper levels, resulting in the increase of water vapor accumulation at these levels. Evaporation term also plays an important role in precipitation, accounting for about 13% of the total precipitation and 23% of the horizontal moisture convergence. The moisture of the typhoon comes mainly from its southern boundary and the secondary inflow of moisture is from its western or eastern boundary. All the inflow layers of these three boundaries are very deep, reaching up to 300 hPa, while the strongest inflow occurs below 700 hPa. In the northern boundary of the typhoon, we obtained that 相似文献
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By utilizing the denser upper-air observations from the Okinawa region and Japanese islands during August 17-23, 1975, the vertical transports of heat and moisture by cumulus convection in the typhoon No. 7507 have been calculated. It is found that there exist a large apparent heat source (Q1) and a moisture sink (Q2) in the southern part of the typhoon at the disturbance, growing and mature stages. The magnitudes of the apparent heat source and moisture sink are rather small, or turn into the apparent heat sink in the northern sector of the typhoon. In the southern part of the typhoon, the total cloud mass flux (Mc) is positive, whereas in the northern part of the typhoon Mc is negative. The above-mentioned distributions of Q1, Q2 and Mc agree well with the major cloud patterns.In the southern part of the typhoon, Q2 is positive because the drying effect is always larger than the evaporative cooling, whereas in the northern part of the typhoon, the opposite case is true because both the drying and evap 相似文献
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利用冲绳和日本列岛等地区较稠密的探空资料对1975年8月17—23日在这地区形成的7号台风进行了结构分析。第一部分主要是台风的切向风、径向风、散度场、涡度场和垂直运动场的分析。分析表明,这个台风的气旋性最大切向风位于台风的东半部,离台风中心约150公里处。最强的流入位于台风南半部300百帕以下深厚层中。在边界层和中层分别有一个最大值。高层最强的反气旋流出在150hPa,主要位于台风东北象限。在台风内区,300百帕以下是对称分布的正涡度最大值区,以上是负涡度区,辐合层主要位于台风南半部。北半部在中低层是辐散层。垂直运动分布有类似的不对称分布特征,上升区主要在南半部,下沉区主要在北半部,并且上升运动最大值及其所在高度与台风发展有十分密切的关系。上述台风运动学场的不对称分布反映了大尺度环流系统(主要是副热带高压和赤道辐合带)对台风结构的影响。 相似文献
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