Revisiting the interannual impact of the Pacific Meridional Mode on tropical cyclone genesis frequency in the Western North Pacific

Wu, Qiong; Zhao, Jiuwei; Zhan, Ruifen; Gao, Jianyun

doi:10.1007/s00382-020-05515-9

Cited by 18 publications

(17 citation statements)

References 61 publications

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“…Figure 4c shows that there is a stable and significant relationship between the PMM and VOR in the NTMDR ( r = .57 during 1979–1998 and r = .55 during 1999–2019). This significant relationship may be due to the PMM's impact of SSTAs on TCSOD via low‐level relative vorticity modulation through a Gill‐type Rossby wave response (Gao et al ., 2020; Wu et al ., 2021).…”

Section: Resultsmentioning

confidence: 99%

“…Several studies have suggested a close relationship between CP ENSO events and PMM events on interannual timescales (Stuecker, 2018; Yu et al ., 2010; Wu et al ., 2021). Given these studies and the results of our study, we speculate that PMM‐driven teleconnections may disrupt ENSO development if the subtropical forcing is out of phase with the tropical climate state.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, Wu et al . (2021) found that when a positive phase of the PMM synchronized with El Niño, TC genesis increased over the southeastern WNP on interannual timescales.…”

Section: Introductionmentioning

confidence: 99%

“…In response to the PMM mode, anomalous off-equatorial heating over the eastern North Pacific can result in an anomalous low-level cyclonic circulation and upper-level anticyclonic circulation over the WNP. Recently, Wu et al (2021) found that when a positive phase of the PMM synchronized with El Niño, TC genesis increased over the southeastern WNP on interannual timescales.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Recent weakening of the relationship between El Niño–Southern Oscillation and western North Pacific tropical cyclone season onset date

Gao

Zhao

Klotzbach

et al. 2022

Intl Journal of Climatology

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This study investigates the climate drivers of western North Pacific (WNP) tropical cyclone season onset date (TCSOD). We find that the interannual relationship between WNP TCSOD and El Niño-Southern Oscillation (ENSO) varies considerably on interdecadal time scales. The association between TCSOD and ENSO, as measured by the Niño3.4 index, is significant during the first subperiod from 1979 to 1998 (r = .51) but becomes insignificant (r = .01) during the second subperiod from 1999 to 2019. This relationship degradation is mainly due to shifting ENSO conditions with more frequent occurrences of tropical central Pacific ENSO events since the late 1990s. Tropical eastern Pacific ENSO events cause changes in the low-level large-scale circulation over the tropical western WNP, where early season WNP TC genesis typically occurs, via a Gill-type Rossby wave response. Tropical central Pacific ENSO events have a limited impact over this region. These relationships are confirmed by a stable and strong association between tropical eastern Pacific ENSO and TCSOD for the whole period (r = .63) and for the two subperiods (r = .72/r = .56), while the correlation between central Pacific ENSO events and TCSOD is weak for the whole period (r = −.01) and for the two subperiods (r = −.03/r = −.13). We further find that the Pacific meridional mode is a robust indicator of TCSOD over the WNP regardless of shifting ENSO conditions. Results of this study may provide useful information for decadal climate prediction of WNP TCSOD.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…Recently, Wu et al . (2021) found that when a positive phase of the PMM synchronized with El Niño, TC genesis increased over the southeastern WNP on interannual timescales.…”

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Recent weakening of the relationship between El Niño–Southern Oscillation and western North Pacific tropical cyclone season onset date

Gao

Zhao

Klotzbach

et al. 2022

Intl Journal of Climatology

View full text Add to dashboard Cite

show abstract

“…Following previous studies (Ashok et al 2007, Kao andYu 2009), the ENSO Modoki index (EMI for brevity) is defined as EMI =SSTA C −0.5 * SSTA E −0.5 * SSTA W , where SSTA C , SSTA E , and SSTA W represent the SST anomalies averaged in the regions of ( 165 In addition to central Pacific SST anomalies, figure 8 shows that obvious SST anomalies also appear in the subtropical eastern Pacific (figure 8(b)). Previous studies have indicated that the Pacific Meridional Mode (PMM), which features an anomalous meridional SST gradient over the subtropical and tropical eastern Pacific (Chiang and Vimont 2004, Zhang et al 2016, 2020, Gao et al 2018, Wu et al 2021, plays a role in the interannual variability of the WNP TC genesis. Zhang et al (2016) suggested that the negative PMM can sustain an anticyclonic circulation and thus suppress the TC genesis over the WNP.…”

Section: Potential Physical Mechanismsmentioning

confidence: 99%

Impact of North America snow cover on tropical cyclogenesis over the western North Pacific

Cao

Sun

et al. 2021

Environ. Res. Lett.

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This study reveals a connection of summer–fall (JJASO) tropical cyclone (TC) genesis over the western North Pacific (WNP) to preceding boreal spring (MAM) North America snow cover (NASC). Sea surface temperature (SST) anomalies in the tropical central Pacific and subtropical eastern Pacific play a crucial role in relaying influence of the MAM NASC on the following JJASO WNP TC genesis frequency. The increased NASC leads to a decrease in upward sensible heat flux and the atmospheric cooling over the North America. The atmospheric cooling enhances the meridional thermal contrast and geopotential height gradient, which is favorable for the occurrence of lower-level westerly wind anomalies and positive precipitation anomalies over the tropical eastern Pacific. The lower-level northeasterly wind anomalies over the subtropical northeastern Pacific as a Gill-type atmospheric response to positive precipitation anomalies induce ocean surface cooling via the enhanced wind speed. A positive feedback between the northeasterly wind anomalies and negative SST anomalies leads to a westward extension of the easterly flows to the western Pacific. The easterly wind anomalies along with the negative specific humidity anomalies and negative lower-level vorticity anomalies, and enhanced vertical wind shear suppress the TC genesis over the WNP during JJASO.

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Asymmetric influence of the Pacific meridional mode on tropical cyclone formation over the western North Pacific

Song,

Klotzbach,

Wang

et al. 2023

Intl Journal of Climatology

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This study investigates the asymmetric response of western North Pacific (WNP) tropical cyclone (TC) formation during August–November to the Pacific meridional mode (PMM) from 1961 to 2021. Basinwide WNP TC frequency significantly increases (slightly decreases) during positive (negative) PMM years, implying a nonlinear PMM–TC frequency relationship. Only small spatial changes in TC formation occur during negative PMM years, while there is nearly a basinwide enhancement of TC formation during positive PMM years, particularly over the region of 5°–30°N and 135°–155°E. This region is characterized by significantly enhanced low‐level vorticity, mid‐level updrafts and upper‐level divergence during positive PMM years, all favouring TC development. By contrast, environmental anomalies are of a smaller magnitude and mostly insignificant over the WNP during negative PMM years. These distinct environmental changes during different PMM phases can be explained by differences in PMM strength. Positive PMM events are of a greater strength and are associated with a stronger wind–evaporation–sea surface temperature feedback than negative PMM events, leading to a notable anomalous large‐scale low‐level cyclonic circulation over the WNP in positive PMM events.

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Revisiting the interannual impact of the Pacific Meridional Mode on tropical cyclone genesis frequency in the Western North Pacific

Cited by 18 publications

References 61 publications

Recent weakening of the relationship between El Niño–Southern Oscillation and western North Pacific tropical cyclone season onset date

Recent weakening of the relationship between El Niño–Southern Oscillation and western North Pacific tropical cyclone season onset date

Impact of North America snow cover on tropical cyclogenesis over the western North Pacific

Asymmetric influence of the Pacific meridional mode on tropical cyclone formation over the western North Pacific

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