Variability and Predictability of Basinwide and Sub-Basin Tropical Cyclone Genesis Frequency in the Northwest Pacific
Variability and Predictability of Basinwide and Sub-Basin Tropical Cyclone Genesis Frequency in the Northwest Pacific
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DOI：
10.1175/jcli-d-21-0232.1
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发表时间：
2022-10
影响因子：
4.9
通讯作者：
W. Mei;Shuo Li
中科院分区：
文献类型：
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作者：
W. Mei;Shuo Li
利用100个60 km分辨率的大气模拟集合，研究了1973-2010年西北太平洋热带气旋生成频率（TCGF）在海盆尺度和次海盆尺度上的变率和可预报性。次海盆区包括南中国海（SCS）和公海的四个象限。系综平均结果很好地再现了观测到的TCGF在东南（SE），东北（NE）和西北（NW）象限的年际到年代际变化，但在南海和西南（SW）象限显示出有限的技能。SE和NE象限中的技能负责模型复制观察到的全流域TCGF变异性的能力。正常TCGF与增强的相对SST（即，在东南、东北和西北象限的观测值和集合平均值中，局部SST减去热带平均SST），但在南海和西南象限的集合平均值中。这些结果表明，强烈的SST控制TCGF在东南，东北和西北象限的经验和理论分析表明，合奏的10，20，35，和15名成员可以捕获SST强迫TCGF变率在这三个子流域地区和整个流域，分别。在西南象限和南海，TCGF包含过多的噪音，特别是在观察，因此显示出较低的可预测性。还讨论了大尺度大气环境和天气尺度扰动的变率和可预报性及其对TCGF的贡献。
The variability and predictability of tropical cyclone genesis frequency (TCGF) during 1973–2010 at both basinwide and sub-basin scales in the northwest Pacific are investigated using a 100-member ensemble of 60-km-resolution atmospheric simulations that are forced with observed sea surface temperatures (SSTs). The sub-basin regions include the South China Sea (SCS) and the four quadrants of the open ocean. The ensemble-mean results well reproduce the observed interannual-to-decadal variability of TCGF in the southeast (SE), northeast (NE), and northwest (NW) quadrants, but show limited skill in the SCS and the southwest (SW) quadrant. The skill in the SE and NE quadrants is responsible for the model’s ability to replicate the observed variability in basinwide TCGF. Above-normal TCGF is tied to enhanced relative SST (i.e., local SST minus tropical-mean SST) either locally or to the southeast of the corresponding regions in both the observations and ensemble mean for the SE, NE, and NW quadrants, but only in the ensemble mean for the SCS and the SW quadrant. These results demonstrate the strong SST control of TCGF in the SE, NE, and NW quadrants; both empirical and theoretical analyses suggest that ensembles of ∼10, 20, 35, and 15 members can capture the SST-forced TCGF variability in these three sub-basin regions and the entire basin, respectively. In the SW quadrant and the SCS, TCGF contains excessive noise, particularly in the observations, and thus shows low predictability. The variability and predictability of the large-scale atmospheric environment and synoptic-scale disturbances and their contributions to those of TCGF are also discussed.