scholarly journals A genesis potential index for Western North Pacific tropical cyclones by using oceanic parameters

2016 ◽  
Vol 121 (9) ◽  
pp. 7176-7191 ◽  
Author(s):  
Min Zhang ◽  
Lei Zhou ◽  
Dake Chen ◽  
Chunzai Wang
Keyword(s):  
Tropical Cyclones ◽  
North Pacific ◽  
Western North Pacific ◽  
Genesis Potential Index ◽  
Potential Index

Variations in High-frequency Oscillations of Tropical Cyclones over the Western North Pacific

2018 ◽  
Vol 35 (4) ◽  
pp. 423-434
Author(s):  
Shumin Chen ◽  
Weibiao Li ◽  
Zhiping Wen ◽  
Mingsen Zhou ◽  
Youyu Lu ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
North Pacific ◽  
High Frequency ◽  
Western North Pacific ◽  
High Frequency Oscillations

Interactions between Boreal Summer Intraseasonal Oscillations and Synoptic-Scale Disturbances over the Western North Pacific. Part I: Energetics Diagnosis*

2011 ◽  
Vol 24 (3) ◽  
pp. 927-941 ◽  
Author(s):  
Pang-chi Hsu ◽  
Tim Li ◽  
Chih-Hua Tsou
Keyword(s):  
Kinetic Energy ◽  
Energy Conversion ◽  
Tropical Cyclones ◽  
North Pacific ◽  
Western North Pacific ◽  
Intraseasonal Oscillation ◽  
Active Phase ◽  
Boreal Summer ◽  
Synoptic Eddies ◽  
Barotropic Energy Conversion

Abstract The role of scale interactions in the maintenance of eddy kinetic energy (EKE) during the extreme phases of the intraseasonal oscillation (ISO) is examined through the construction of a new eddy energetics diagnostic tool that separates the effects of ISO and a low-frequency background state (LFBS; with periods longer than 90 days). The LFBS always contributes positively toward the EKE in the boreal summer, regardless of the ISO phases. The synoptic eddies extract energy from the ISO during the ISO active phase. This positive barotropic energy conversion occurs when the synoptic eddies interact with low-level cyclonic and convergent–confluent ISO flows. This contrasts with the ISO suppressed phase during which the synoptic eddies lose kinetic energy to the ISO flow. The anticyclonic and divergent–diffluent ISO flows during the suppressed phase are responsible for the negative barotropic energy conversion. A positive (negative) EKE tendency occurs during the ISO suppressed-to-active (active-to-suppressed) transitional phase. The cause of this asymmetric EKE tendency is attributed to the spatial phase relation among the ISO vorticity, eddy structure, and EKE. The southwest–northeast-tilted synoptic disturbances interacting with cyclonic (anticyclonic) vorticity of ISO lead to a positive (negative) EKE tendency in the northwest region of the maximum EKE center. The genesis number and location and intensification rate of tropical cyclones in the western North Pacific are closely related to the barotropic energy conversion. The enhanced barotropic energy conversion favors the generation and development of synoptic seed disturbances, some of which eventually grow into tropical cyclones.

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