Abstract
The tropical western North Pacific displays prominent synoptic-scale disturbances (SSDs) during boreal summer. The present study investigates interannual variations of boreal summer SSD intensity (measured using the kinetic energy of 3–9-day filtered 850 hPa winds) over the tropical western North Pacific and the associated factors. The first EOF mode of the SSD intensity variation displays a southeast–northwest tilted structure and the second EOF mode features a west–east contrasting pattern. El Niño–Southern Oscillation (ENSO) influences the intensity of the SSDs over the tropical western North Pacific in three ways. The first way is a Rossby wave response to the equatorial central-eastern Pacific sea surface temperature (SST) anomalies, which modulates the seasonal mean background fields over the source region and along the propagation path of the SSDs. The second way is an anomalous Walker circulation response that modulates the seasonal mean background fields over the far western equatorial Pacific that is a source region of northward propagating SSDs. The third way is an anomalous Walker circulation response that modulates the seasonal mean background fields over the Philippine Sea. The first and third ways operate for the first mode and the first and second ways work for the second mode. The third mode has a large loading over the subtropical western North Pacific and is related to the internal atmospheric process. The relative contributions of different terms of the barotropic energy conversion associated with the seasonal mean background fields vary with the region and differ among the three modes.
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References
Bi M, Li T, Shen X, Peng M (2015) To what extent the presence of real-strength tropical cyclones influences the estimation of atmospheric intraseasonal oscillation intensity? Atmos Sci Lett 16:438–444. https://doi.org/10.1002/asl.579
Cao X, Huang P, Chen G, Chen W (2012) Modulation of western North Pacific tropical cyclone genesis by intraseasonal oscillation of the ITCZ: a statistical analysis. Adv Atmos Sci 29:744–754. https://doi.org/10.1007/s00376-012-1121-0
Chen G (2012) A comparison of the transition of equatorial waves between two types of ENSO events in a multilevel model. J Atmos Sci 69:2364–2378. https://doi.org/10.1175/JAS-D-11-0292.1
Chen G, Huang R (2009) Interannual variations in mixed Rossby–gravity waves and their impacts on tropical cyclogenesis over the western North Pacific. J Clim 22:535–549. https://doi.org/10.1175/2008JCLI2221.1
Chen T-C, Weng S-P (1998) Interannual variation of the summer synoptic-scale disturbance activity in the western tropical Pacific. Mon Weather Rev 126:1725–1733. https://doi.org/10.1175/1520-0493(1998)126%3c1725:IVOTSS%3e2.0.CO;2
Dickinson M, Molinari J (2002) Mixed Rossby–gravity waves and western Pacific tropical cyclogenesis. Part I: synoptic evolution. J Atmos Sci 59:2183–2196. https://doi.org/10.1175/1520-0469(2002)059%3c2183:MRGWAW%3e2.0.CO;2
Feng T, Yang X-Q, Zhou W, Huang R, Wu L, Yang D (2016) Synoptic-scale waves in sheared background flow over the western North Pacific. J Atmos Sci 73:4583–4603. https://doi.org/10.1175/JAS-D-16-0064.1
Feng T, Yang X-Q, Yu J-Y, Huang R (2020) Convective coupling in tropical-depression-type waves. Part I: rainfall characteristics and moisture structure. J Atmos Sci 77:3407–3422. https://doi.org/10.1175/JAS-D-19-0172.1
Frank WM, Roundy PE (2006) The role of tropical waves in tropical cyclogenesis. Mon Weather Rev 134:2397–2417. https://doi.org/10.1175/MWR3204.1
Fu B, Li T, Peng MS, Weng F (2007) Analysis of tropical cyclogenesis in the western North Pacific for 2000 and 2001. Weather Forecast 22:763–780. https://doi.org/10.1175/WAF1013.1
He Z, Wu R (2014) Indo-Pacific remote forcing in summer rainfall variability over the South China Sea. Clim Dyn 42(9–10):2323–2337. https://doi.org/10.1007/s00382-014-2123-7
Hsu P-C, Li T (2011) Interactions between boreal summer intraseasonal oscillations and synoptic-scale disturbances over the western North Pacific. Part II: apparent heat and moisture sources and eddy momentum transport. J Clim 24:942–961. https://doi.org/10.1175/2010JCLI3834.1
Hsu P-C, Tsou CH, Hsu H-H, Chen J-H (2009) Eddy energy along the tropical storm track in association with ENSO. J Meteorol Soc Jpn 87:687–704. https://doi.org/10.2151/jmsj.87.687
Hu P, Huangfu J, Chen W, Huang R (2020) South China Sea summer monsoon withdrawal and the synoptic-scale wave train over the western North Pacific. Int J Climatol 40:5599–5611. https://doi.org/10.1002/joc.6538
Huangfu J, Cao X, Wu R, Chen G, Chen W (2022) Influences of central Pacific warming on synoptic-scale wave intensity over the northwest Pacific. Clim Dyn 58:555–567. https://doi.org/10.1007/s00382-021-05922-6
Hurley JV, Boos WR (2015) A global climatology of monsoon low-pressure systems. Q J R Meteorol Soc 141:1049–1064. https://doi.org/10.1002/qj.2447
Kanamitsu M, Ebisuzaki W, Woollen J et al (2002) NCEP–DOE AMIP-II Reanalysis (R-2). Bull Am Meteorol Soc 83:1631–1644. https://doi.org/10.1175/BAMS-83-11-1631
Kuo H-C, Chen J-H, Williams RT, Chang CP (2001) Rossby waves in zonally opposing mean flow: behavior in northwest Pacific summer monsoon. J Atmos Sci 58:1035–1050. https://doi.org/10.1175/1520-0469(2001)058%3c1035:RWIZOM%3e2.0.CO;2
Kurihara Y, Bender MA, Tuleya RE, Ross RJ (1995) Improvements in the GFDL hurricane prediction system. Mon Weather Rev 123:2791–2801. https://doi.org/10.1175/1520-0493(1995)123%3c2791:IITGHP%3e2.0.CO;2
Lau K-H, Lau N-C (1990) Observed structure and propagation characteristics of tropical summertime synoptic scale disturbances. Mon Weather Rev 118:1888–1913. https://doi.org/10.1175/1520-0493(1990)118%3c1888:OSAPCO%3e2.0.CO;2
Lau N-C, Nath MJ (2003) Atmosphere–ocean variations in the Indo-Pacific sector during ENSO episodes. J Clim 16:3–20. https://doi.org/10.1175/1520-0442(2003)016%3c0003:AOVITI%3e2.0.CO;2
Li T (2006) Origin of the summertime synoptic-scale wave train in the western North Pacific. J Atmos Sci 63:1093–1102. https://doi.org/10.1175/JAS3676.1
Maloney ED, Dickinson MJ (2003) The intraseasonal oscillation and the energetics of summertime tropical western North Pacific synoptic-scale disturbances. J Atmos Sci 60:2153–2168. https://doi.org/10.1175/1520-0469(2003)060%3c2153:TIOATE%3e2.0.CO;2
Maloney ED, Hartmann DL (2001) The Madden–Julian Oscillation, barotropic dynamics, and North Pacific tropical cyclone formation. Part I: observations. J Atmos Sci 58:2545–2558. https://doi.org/10.1175/1520-0469(2001)058%3c2545:TMJOBD%3e2.0.CO;2
Molinari J, Lombardo K, Vollaro D (2007) Tropical cyclogenesis within an equatorial Rossby wave packet. J Atmos Sci 64:1301–1317. https://doi.org/10.1175/JAS3902.1
North GR, Bell TL, Cahalan RF, Moeng FJ (1982) Sampling errors in the estimation of empirical orthogonal functions. Mon Weather Rev 110:699–706. https://doi.org/10.1175/1520-0493(1982)110%3c0699:SEITEO%3e2.0.CO;2
Reynolds RW, Rayner NA, Smith TM et al (2002) An improved in situ and satellite SST analysis for climate. J Clim 15:1609–1625. https://doi.org/10.1175/1520-0442(2002)015%3c1609:AIISAS%3e2.0.CO;2
Sobel AH, Bretherton CS (1999) Development of synoptic-scale disturbances over the summertime tropical northwest Pacific. J Atmos Sci 56:3106–3127. https://doi.org/10.1175/1520-0469(1999)056%3c3106:DOSSDO%3e2.0.CO;2
Tam C-Y, Li T (2006) The origin and dispersion characteristics of the observed tropical summertime synoptic-scale waves over the western Pacific. Mon Weather Rev 134:1630–1646. https://doi.org/10.1175/MWR3147.1
Wang Y, Wu R (2021) Factors of boreal summer latent heat flux variations over the tropical western North Pacific. Clim Dyn 57:2753–2765. https://doi.org/10.1007/s00382-021-05835-4
Wang B, Wu R, Fu X (2000) Pacific-East Asian teleconnection: how does ENSO affect East Asian climate? J Clim 13:1517–1536. https://doi.org/10.1175/1520-0442(2000)013%3c1517:PEATHD%3e2.0.CO;2
Wang B, Wu R, Li T (2003) Atmosphere–warm ocean interaction and its impacts on Asian-Australian monsoon variation. J Clim 16:1195–1211. https://doi.org/10.1175/1520-0442(2003)16%3c1195:AOIAII%3e2.0.CO;2
Wang Y, Wu R, Jiao Y (2020) Upscale feedback of high-frequency winds on seasonal SST change over the tropical western North Pacific during boreal summer. Clim Dyn 55:2439–2451. https://doi.org/10.1007/s00382-020-05391-3
Wang Y, Wu R, Gu Q (2022) Asymmetric changes in intraseasonal oscillation intensity over the tropical western North Pacific in El Niño and La Niña developing summers. J Clim 35(8):2617–2631. https://doi.org/10.1175/JCLI-D-21-0615.1
Webster PJ, Chang H-R (1988) Equatorial energy accumulation and emanation regions: Impacts of a zonally varying basic state. J Atmos Sci 45:803–829. https://doi.org/10.1175/1520-0469(1988)045%3c0803:EEAAER%3e2.0.CO;2
Wu R, Wang B (2000) Interannual variability of summer monsoon onset over the western North Pacific and the underlying processes. J Clim 13(14):2483–2501
Wu R, Hu Z-Z, Kirtman BP (2003) Evolution of ENSO-related rainfall anomalies in East Asia. J Clim 16:3742–3758. https://doi.org/10.1175/1520-0442(2003)016%3c3742:EOERAI%3e2.0.CO;2
Wu R, Yang S, Wen Z, Huang G, Hu K (2012) Interdecadal change in the relationship of southern China summer rainfall with tropical Indo-Pacific SST. Theor Appl Climatol 108(1):119–133. https://doi.org/10.1007/s00704-011-0519-4
Wu L, Wen Z, Li T, Huang R (2014) ENSO-phase dependent TD and MRG wave activity in the western North Pacific. Clim Dyn 42:1217–1227. https://doi.org/10.1007/s00382-013-1754-4
Wu L, Wen Z, Wu R (2015) Influence of the monsoon trough on westward-propagating tropical waves over the western North Pacific. Part I: observations. J Clim 28:7108–7127. https://doi.org/10.1175/JCLI-D-14-00806.1
Wu R, Wang Y, Jiao Y (2020a) High frequency wind-related seasonal mean latent heat flux changes. Clim Dyn 55:3269–3287. https://doi.org/10.1007/s00382-020-05445-6
Wu R, Jiao Y, Wang Y, Jia X (2020b) High-frequency wind-related seasonal mean latent heat flux changes over the tropical Indo-western Pacific in El Niño and La Niña years. J Geophys Res 125(21):e2020JD032954. https://doi.org/10.1029/2020JD032954
Wu R, Wang Y, Cao X (2021) What modulates the intensity of synoptic-scale variability over the western North Pacific during boreal summer and fall? J Clim 34:3645–3662. https://doi.org/10.1175/JCLI-D-20-0477.1
Xie X, Wang B (1996) Low-frequency equatorial waves in vertically sheared zonal flow. Part II: unstable waves. J Atmos Sci 53:3589–3605. https://doi.org/10.1175/1520-0469(1996)053%3c3589:LFEWIV%3e2.0.CO;2
Yokoi S, Matsumoto J (2008) Collaborative effects of cold surge and tropical depression type disturbance on heavy rainfall in Central Vietnam. Mon Weather Rev. https://doi.org/10.1175/2008MWR2456.1
Zhou X, Lu R, Chen G, Wu L (2018) Interannual variations in synoptic-scale disturbances over the western North Pacific. Adv Atmos Sci 35:507–517. https://doi.org/10.1007/s00376-017-7143-x
Zipser EJ (1970) The line islands experiment, its place in tropical meteorology and the rise of the fourth school of thought. Bull Am Meteorol Soc 51:1136–1147. https://doi.org/10.1175/1520-0477-51.12.1136
Acknowledgements
Comments of three anonymous reviewers are appreciated. This study is supported by the National Natural Science Foundation of China Grant (41721004). The NCEP-DOE reanalysis 2 data were obtained from ftp://ftp.cdc.noaa.gov/. The NOAA OI version 2 SST data were obtained from http://www.esrl.noaa.gov/psd/.
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The research is supported by the National Natural Science Foundation of China Grants (41721004).
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RW contributed to the concept and design of the research. QG conducted the analysis and prepared the draft. RW acquired the funding. All the authors contributed to the revising of the paper.
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Gu, Q., Wu, R. & Cao, X. Interannual variations of synoptic-scale disturbance intensity over the tropical western North Pacific during boreal summer. Clim Dyn 61, 1913–1930 (2023). https://doi.org/10.1007/s00382-023-06663-4
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DOI: https://doi.org/10.1007/s00382-023-06663-4