ENSO在青藏高原积雪与西北太平洋热带气旋生成频数关系中的作用

发布时间：2018-04-08 08:33

本文选题：西北太平洋　切入点：热带气旋　出处：《中国科学:地球科学》2016年10期

【摘要】：已有研究表明,青藏高原冬季积雪与随后台风季节西北太平洋热带气旋生成频数之间具有典型的负相关.本文基于长时间观测资料对二者关系进行再探讨,发现两者的年际关系在20世纪90年代初发生了跃变,即青藏高原冬季积雪与随后台风季节西北太平洋热带气旋生成频数之间显著的负相关仅存在于20世纪90年代初之后(1993~2012年),而20世纪90年代初之前(1976~1992年)二者的联系较弱.进一步本文对引起这种跃变的可能原因进行了分析,发现中部型ENSO在加强青藏高原积雪与西北太平洋热带气旋生成频数关系中起到了至关重要的作用.1993~2012年间,青藏高原积雪与中部型ENSO存在显著的负相关.在青藏高原积雪偏多年(少),中部型ENSO多为冷位相(暖位相),这种分布一方面加强了青藏高原积雪与纬向海陆热力差异继而与西北太平洋夏季风的联系,另一方面加强了青藏高原积雪对热带气旋生成相关的动力环境场的调控,因此在这一时段青藏高原积雪与热带气旋生成频数之间的相关得到了显著增强.然而,在前一时段青藏高原积雪与ENSO的联系较弱,青藏高原积雪对西北太平洋夏季风和台风生成区域动力场调控较弱,因而其与热带气旋生成频数之间的关系减弱.此外,通过能量诊断进一步表明,在1993~2012年中部型ENSO的作用主要是通过加强西北太平洋纬向风的正压能量转化来实现的.结果将为提高热带气旋短期气候预测水平提供一定的理论基础.
[Abstract]:It has been shown that there is a typical negative correlation between the snow cover in winter and the frequency of tropical cyclones in the Northwest Pacific Ocean during the subsequent typhoon season over the Qinghai-Xizang Plateau.Based on the long-time observation data, this paper restudies the relationship between the two. It is found that the interannual relationship between the two has changed rapidly in the early 1990s.That is to say, the significant negative correlation between snow cover in winter and frequency of tropical cyclones in the Northwest Pacific Ocean during the subsequent typhoon season only existed in 1993 ~ 2012 after the beginning of 1990s, but was weak in 1976-1992 before the beginning of 1990s.In this paper, the possible causes of this jump are analyzed. It is found that the central type of ENSO plays an important role in strengthening the relationship between snow cover over the Qinghai-Tibet Plateau and the frequency of tropical cyclones in the Northwest Pacific Ocean.There is a significant negative correlation between snow cover and central type ENSO in Qinghai-Xizang Plateau.In the Qinghai-Xizang Plateau, the snow cover has been in the cold phase (warm phase) for many years, and the central type of ENSO is mostly cold phase (warm phase).On the other hand, the regulation of snow cover on the dynamic environmental field associated with the formation of tropical cyclones in the Qinghai-Xizang Plateau is strengthened, so the correlation between snow cover and the frequency of tropical cyclones over the Qinghai-Xizang Plateau has been significantly enhanced during this period.However, the relationship between snow cover and ENSO in the Qinghai-Xizang Plateau was weak in the previous period, and the relationship between the snow cover and the frequency of tropical cyclones was weakened due to the weak regulation of the dynamic field of summer monsoon and typhoon formation in the Northwest Pacific Ocean.In addition, the energy diagnosis further indicates that the role of ENSO in the central region from 1993 to 2012 is mainly realized by strengthening the barotropic energy transformation of the latitudinal wind in the Northwest Pacific Ocean.The results will provide a theoretical basis for improving the level of short-term climate prediction of tropical cyclones.
【作者单位】：中国气象局上海台风研究所;中国气象局国家气候中心;南京信息工程大学气象灾害教育部重点实验室;
【基金】：公益性行业(气象)科研专项项目(编号:GYHY201406001) 国家重点基础研究发展计划项目(编号:2012CB956003) 国家自然科学基金项目(批准号:41375093)资助
【分类号】：P444;P732

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