2017年西北太平洋台风活动异常特征及成因分析

Analysis of Anomalous Typhoon Activities over the Western North Pacific in 2017

本文通过分析2017年西北太平洋台风活动以及有关大气和海洋资料,总结了西北太平洋台风活动异常特征,并进行了成因分析。2017年西北太平洋台风活动的异常特征主要表现为:总数略偏多,但整体弱,超强台风少;南海台风多,“暖池”台风少;台风活动集中爆发。台风活动异常的主要原因包括:西太平洋副热带高压强度显著偏强、位置偏南偏西,不利于台风(特别是强台风)的生成发展;西北太平洋菲律宾以东“暖池”上空为异常下沉区,对台风的生成和发展不利,而南海为异常上升区,有利于台风的生成和发展;2016~2017年热带海洋La Niña事件发展未遂,对西北太平洋台风活动的影响不足;2017年西北太平洋的两次台风活动集中爆发过程与热带大气季节内振荡(MJO)活动紧密相关。

This article summarized the characteristics of anomalous typhoon activities and conducted the possible reasons, using typhoon activities data along with the atmospheric and oceanic data over the Western North Pacific (WNP) in 2017. The characteristics of anomalous typhoon activities over the WNP in 2017 mainly manifested on slightly more total amount, overall weakness and rare super typhoon;typhoons generated over the South China Sea (SCS) were more and less over the WNP Warm Pool (WP);typhoon activities busted out centrally. The reasons of anomalous typhoon activities over the WNP mainly included: the Western Pacific subtropical high was abnormally powerful, its position was farther southern and western, made difficult to typhoon activities, especially to super typhoon activities over the WNP;the abnormal sinking airflow made against typhoon activities over the WNP, WP, and the abnormal lift airflow in favor of typhoon activities over the SCS;the unaccomplished development of La Niña event from 2016 to 2017 over tropical oceans had less effect on typhoon activities over the WNP;the twice centrally outbreaks of typhoon activities over the WNP were closely connected with Maddan-Julian Oscillation (MJO) in tropical atmosphere.