南海热带气旋极端快速加强标准研究

Definition of Extremely Rapid Intensification of Tropical Cyclones over the South China Sea for Operational Forecasting

关键词:  热带气旋  极端快速加强  标准  南海

Key words:  tropical cyclone  extremely rapid intensification  definition  South China Sea

摘要:

为得到适合业务使用的南海热带气旋（TC）极端快速加强（ERI）标准，了解 ERI TC 的统计特征，利用中国气象局上海台风研究所整编的 1981—2022 年西北太平洋 TC 最佳路径资料，取 TC 强度变化最大值为样本，对比分析了平均值法、百分位数法。（1）98 百分位数定义的标准能较好地体现 TC 快速加强的极端性，以及西北太平洋和南海TC强度发展程度上的差异，在业务预报上的适用性较强。（2）南海ERI标准为强度加强不小于10 m·s-1·(6 h)-1、13 m·s-1·(12 h)-1、20 m·s-1·(24 h)-1。西北太平洋ERI标准为强度加强不小于10 m·s-1·(6 h)-1、20 m·s-1·(12 h)-1、30 m·s-1·(24 h)-1。（3）TC ERI是一个小概率事件，在西北太平洋和南海分别占 TC总数的 12%和 4%，主要发生在菲律宾以东的 135～145 °E，15～20 °N 洋面和 20 °N 附近的南海北部海面，自 20 世纪 90 年代以来出现频率呈增加趋势。（4）南海出现 ERI后的 TC有 72% 登陆我国，登陆海南和广东的最多，其中 69%出现在2000年以后。南海ERI TC呈现距陆地近、登陆时间短、登陆强度强的特点。

Abstract:

The definition of extremely rapid intensification (ERI) of tropical cyclones (TCs) and the statistical characteristics of TCs that experienced ERI (ERI TCs) over the South China Sea (SCS) were studied using the best track dataset from the Shanghai Typhoon Institute of China Meteorological Administration for TCs during 1981-2022. ERI was defined as intensity increases of at least 10 m · s-1 · (6 h) -1, 13 m·s-1·(12 h) -1, and 20 m·s-1·(24 h) -1 over the SCS and 10 m·s-1·(6 h) -1, 20 m·s-1·(12 h) -1, and 30 m · s-1 · (24 h) -1 over the western North Pacific (WNP), which corresponds to the 98th percentile of maximum intensity change for all TCs. Compared with conventional methods, the proposed ERI definition better describes the extremity of rapidly intensifying TCs and the intensity development difference between TCs over the WNP and the SCS. This makes it more useful for TC operational forecasting. Only 12% of TCs over the WNP and 4% of TCs over the SCS underwent ERI, and they were mainly located over the region bounded by 135~145 °E, 15~20 °N and the northern SCS near 20 °N. 72% of ERI TCs over the SCS made landfall in China, mostly in Hainan and Guangdong provinces, and 69% of these landing TCs occurred after 2000. ERI TCs over the SCS exhibited characteristics of being close to land, with short landing time and strong landing intensity, which significantly increased the difficulty of TC forecasting and disaster mitigation.