Editorial Type:
Article
Article Type:
Research Article

Observations of Upper-Tropospheric Influence on a Monsoon Trough over the Western North Pacific

Biao Geng Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan

Search for other papers by Biao Geng in
Current site
Google Scholar
PubMed Close
,
Kunio Yoneyama Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan

Search for other papers by Kunio Yoneyama in
Current site
Google Scholar
PubMed Close
, and
Ryuichi Shirooka Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan

Search for other papers by Ryuichi Shirooka in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Apr 2014
DOI:
https://doi.org/10.1175/MWR-D-13-00233.1
Page(s):
1472–1488
Restricted access

Abstract

This study examined the synoptic evolution and internal structure of a monsoon trough in association with the deep equatorward intrusion of a midlatitude upper trough in the western North Pacific Ocean in June 2008. The study was based on data from routine synoptic observations and intensive observations conducted on board the research vessel Mirai at 12°N, 135°E. The monsoon trough was first observed to extend southeastward from the center of a tropical depression. It then moved northward, with its eastern edge moving faster and approaching a surface low pressure cell induced by the upper trough. The distinct northward migration caused the monsoon trough to become oriented from the southwest to the northeast. The monsoon trough merged with the surface low pressure cell and extended broadly northeastward. The passage of the monsoon trough over the Mirai was accompanied by lower pressure, higher air and sea surface temperature, and minimal rainfall. The monsoon trough extended upward to nearly 500 hPa and sloped southward with height. It was overlain by northwesterly winds, negative geopotential height and temperature anomalies, and extremely dry air in the upper troposphere. Precipitation systems were weak and scattered near the monsoon trough but were intense and extensive south of the surface monsoon trough, where intense low-level convergence and upper-level divergence caused deep and vigorous upward motion. It appears that the upper trough exerted important impacts on the development of both the monsoon trough and associated precipitation, which are discussed according to the observational results.

Corresponding author address: Dr. Biao Geng, Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima, Yokosuka, 237-0061, Japan. E-mail: bgeng@jamstec.go.jp

Abstract

This study examined the synoptic evolution and internal structure of a monsoon trough in association with the deep equatorward intrusion of a midlatitude upper trough in the western North Pacific Ocean in June 2008. The study was based on data from routine synoptic observations and intensive observations conducted on board the research vessel Mirai at 12°N, 135°E. The monsoon trough was first observed to extend southeastward from the center of a tropical depression. It then moved northward, with its eastern edge moving faster and approaching a surface low pressure cell induced by the upper trough. The distinct northward migration caused the monsoon trough to become oriented from the southwest to the northeast. The monsoon trough merged with the surface low pressure cell and extended broadly northeastward. The passage of the monsoon trough over the Mirai was accompanied by lower pressure, higher air and sea surface temperature, and minimal rainfall. The monsoon trough extended upward to nearly 500 hPa and sloped southward with height. It was overlain by northwesterly winds, negative geopotential height and temperature anomalies, and extremely dry air in the upper troposphere. Precipitation systems were weak and scattered near the monsoon trough but were intense and extensive south of the surface monsoon trough, where intense low-level convergence and upper-level divergence caused deep and vigorous upward motion. It appears that the upper trough exerted important impacts on the development of both the monsoon trough and associated precipitation, which are discussed according to the observational results.

Corresponding author address: Dr. Biao Geng, Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima, Yokosuka, 237-0061, Japan. E-mail: bgeng@jamstec.go.jp
Save
Cover Monthly Weather Review
Monthly Weather Review

  • Allen, G., G. Vaughan, D. Brunner, P. T. May, W. Heyes, P. Minnisd, and J. K. Ayers, 2009: Modulation of tropical convection by breaking Rossby waves. Quart. J. Roy. Meteor. Soc., 135, 125–137, doi:10.1002/qj.349.

    • Search Google Scholar
    • Export Citation

  • Atlas, R., R. N. Hoffman, J. Ardizzone, S. M. Leidner, J. C. Jusem, D. K. Smith, and D. Gombos, 2011: A cross-calibrated, multiplatform ocean surface wind velocity product for meteorological and oceanographic applications. Bull. Amer. Meteor. Soc., 92, 157–174, doi:10.1175/2010BAMS2946.1.

    • Search Google Scholar
    • Export Citation

  • Bayo Omotosho, J., 1985: The separate contributions of line squalls, thunderstorms and the monsoon to the total rainfall in Nigeria. Int. J. Climatol., 5, 543–552, doi: 10.1002/joc.3370050507.

    • Search Google Scholar
    • Export Citation

  • Beattie, J. C., and R. L. Elsberry, 2012: Western North Pacific monsoon depression formation. Wea. Forecasting, 27, 1413–1432, doi:10.1175/WAF-D-11-00094.1.

    • Search Google Scholar
    • Export Citation

  • Carr, L. E., III, and R. L. Elsberry, 1994: Systematic and integrated approach to tropical cyclone track forecasting. Part I. Approach overview and description of meteorological basis. Tech. Rep. NPS-MR-94-002, Naval Postgraduate School, Monterey, CA, 273 pp.

  • Chen, T. C., S. Y. Wang, M. C. Yen, and A. J. Clark, 2009: Impact of the intraseasonal variability of the western North Pacific large-scale circulation on tropical cyclone tracks. Wea. Forecasting, 24, 646–666, doi:10.1175/2008WAF2222186.1.

    • Search Google Scholar
    • Export Citation

  • Chia, H. H., and C. F. Ropelewski, 2002: The interannual variability in the genesis location of tropical cyclones in the northwest Pacific. J. Climate, 15, 2934–2944, doi:10.1175/1520-0442(2002)015<2934:TIVITG>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Davidson, N., K. J. Tory, M. J. Reeder, and W. L. Drosdowsky, 2007: Extratropical–tropical interaction during onset of the Australian monsoon: Reanalysis diagnostics and idealized dry simulations. J. Atmos. Sci., 64, 3475–3498, doi:10.1175/JAS4034.1.

    • Search Google Scholar
    • Export Citation

  • Geng, B., K. Yoneyama, R. Shirooka, and M. Yoshizaki, 2011: Characteristics of precipitation systems and their environment observed during the onset of the western North Pacific summer monsoon in 2008. J. Meteor. Soc. Japan, 89A, 1–25, doi:10.2151/jmsj.2011-A01.

    • Search Google Scholar
    • Export Citation

  • Harr, P. A., and R. L. Elsberry, 1995: Large-scale circulation variability over the tropical western North Pacific. Part I: Spatial patterns and tropical cyclone characteristics. Mon. Wea. Rev., 123, 1225–1246, doi:10.1175/1520-0493(1995)123<1225:LSCVOT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Harr, P. A., and J. C. L. Chan, 2005: Monsoon impacts on tropical cyclone variability. WMO Tech. Doc. 1266, TMPR Rep. 70, WMO, 512–542.

  • Harr, P. A., and C.-C. Wu, 2011: Tropical cyclone characteristics and monsoon circulations. The Global Monsoon System: Research and Forecast, 2nd ed. C.-P. Chang et al., Eds., World Scientific Publishing, 357–372.

  • Holland, G. J., 1995: Scale interaction in the western Pacific monsoon. Meteor. Atmos. Phys., 56, 57–79, doi:10.1007/BF01022521.

  • Hsu, H.-H., 2005: East Asian monsoon. Intraseasonal Variability in the Atmosphere-Ocean Climate System, K.-M. Lau and D. Waliser, Eds., Springer, 63–94.

  • Hung, C. W., and M. Yanai, 2004: Factors contributing to the onset of the Australian summer monsoon. Quart. J. Roy. Meteor. Soc., 130, 739–758, doi:10.1256/qj.02.191.

    • Search Google Scholar
    • Export Citation

  • Kuo, H. L., 1949: Dynamic instability of two-dimensional nondivergent flow in a barotropic atmosphere. J. Meteor., 6, 105–122, doi:10.1175/1520-0469(1949)006<0105:DIOTDN>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Lander, M. A., 1994: Description of a monsoon gyre and its effect on the tropical cyclones in the western North Pacific during August 1991. Wea. Forecasting, 9, 640–654, doi:10.1175/1520-0434(1994)009<0640:DOAMGA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Lander, M. A., 1996: Specific tropical cyclone track types and unusual tropical cyclone motions associated with a reverse-oriented monsoon trough in the western North Pacific. Wea. Forecasting, 11, 170–186, doi:10.1175/1520-0434(1996)011<0170:STCTTA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Li, R., and W. Zhou, 2013a: Modulation of western North Pacific tropical cyclone activity by the ISO. Part I: Genesis and intensity. J. Climate, 26, 2904–2918, doi:10.1175/JCLI-D-12-00210.1.

    • Search Google Scholar
    • Export Citation

  • Li, R., and W. Zhou, 2013b: Modulation of western North Pacific tropical cyclone activity by the ISO. Part II: Tracks and landfalls. J. Climate, 26, 2919–2930, doi:10.1175/JCLI-D-12-00211.1.

    • Search Google Scholar
    • Export Citation

  • Love, G., 1985: Cross-equatorial influences of winter hemisphere subtropical cold surges. Mon. Wea. Rev., 113, 1487–1498, doi:10.1175/1520-0493(1985)113<1487:CEIOWH>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Maloney, E. D., and M. J. Dickinson, 2003: The intraseasonal oscillation and the energetics of summertime tropical western North Pacific synoptic-scale disturbances. J. Atmos. Sci., 60, 2153–2168, doi:10.1175/1520-0469(2003)060<2153:TIOATE>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Mao, J. G., and G. X. Wu, 2010: Intraseasonal modulation of tropical cyclogenesis in the western North Pacific: A case study. Theor. Appl. Climatol., 100, 397–411, doi:10.1007/s00704-009-0195-9.

    • Search Google Scholar
    • Export Citation

  • Mapes, B. E., and J. Lin, 2005: Doppler radar observations of mesoscale wind divergence in regions of tropical convection. Mon. Wea. Rev., 133, 1808–1824, doi:10.1175/MWR2941.1.

    • Search Google Scholar
    • Export Citation

  • Miller, F. R., and R. N. Keshvarnurty, 1968: Structure of an Arabian Sea Summer Monsoon System. IIOE Meteor. Monogr., East-West Centre Press, 94 pp.

  • Molinari, J., and D. Vollaro, 2013: What percentage of western North Pacific tropical cyclones form within the monsoon trough? Mon. Wea. Rev., 141, 499–505, doi:10.1175/MWR-D-12-00165.1.

    • Search Google Scholar
    • Export Citation

  • Parsons, D. B., K. Yoneyama, and J.-L. Redelsperger, 2000: The evolution of the tropical western Pacific atmosphere–ocean system following the arrival of a dry intrusion. Quart. J. Roy. Meteor. Soc., 126, 517–548, doi:10.1002/qj.49712656307.

    • Search Google Scholar
    • Export Citation

  • Postel, G. A., and M. H. Hitchman, 1999: A climatology of Rossby wave breaking along the subtropical tropopause. J. Atmos. Sci., 56, 359–373, doi:10.1175/1520-0469(1999)056<0359:ACORWB>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Raghavan, K., 1973: Break monsoon over India. Mon. Wea. Rev., 101, 33–43, doi:10.1175/1520-0493(1973)101<0033:BOI>2.3.CO;2.

  • Ramage, C. S., 1971: Monsoon Meteorology. Academic Press, 296 pp.

  • Ramage, C. S., 1974: Structure of an oceanic near-equatorial trough deduced from research aircraft traverses. Mon. Wea. Rev., 102, 754–759, doi:10.1175/1520-0493(1974)102<0754:SOAONE>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Sadler, J. C., 1964: TIROS observations of the summer circulation and weather patterns of the Eastern North Pacific. Proc. Symp. on Tropical Meteorology, Rotorua, New Zealand, New Zealand Meteorological Service, 553–571.

  • Sadler, J. C., 1967: On the origin of tropical vortices. Proc. Working Panel on Tropical Dynamic Meteorology, Norfolk, VA, Naval Weather Research Facility, 39–75.

  • Sadler, J. C., 1975: The monsoon circulation and cloudiness over the GATE area. Mon. Wea. Rev., 103, 369–387, doi:10.1175/1520-0493(1975)103<0369:TMCACO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Sadler, J. C., 1976: A role of the tropical upper tropospheric trough in early season typhoon development. Mon. Wea. Rev., 104, 1266–1278, doi:10.1175/1520-0493(1976)104<1266:AROTTU>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Sadler, J. C., M. A. Lander, A. M. Hori, and L. K. Oda, 1987: Pacific Ocean. Vol. 2, Tropical Marine Climate Atlas, UHMET Pub. 8702, University of Hawaii at Manoa, 28 pp.

  • Thorncroft, C. D., B. J. Hoskins, and M. E. McIntyre, 1993: Two paradigms of baroclinic-wave life-cycle behaviour. Quart. J. Roy. Meteor. Soc., 119, 17–55, doi:10.1002/qj.49711950903.

    • Search Google Scholar
    • Export Citation

  • Tokay, A., and D. A. Short, 1996: Evidence from tropical raindrop spectra of the origin of rain from stratiform versus convective clouds. J. Appl. Meteor., 35, 355–371, doi:10.1175/1520-0450(1996)035<0355:EFTRSO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Ueda, H., T. Yasunari, and R. Kawamura, 1995: Abrupt seasonal change of large-scale convective activity over the western Pacific in the northern summer. J. Meteor. Soc. Japan, 73, 795–809.

    • Search Google Scholar
    • Export Citation

  • Velden, C. S., and Coauthors, 2005: Recent innovations in deriving tropospheric winds from meteorological satellites. Bull. Amer. Meteor. Soc., 86, 205–223, doi:10.1175/BAMS-86-2-205.

    • Search Google Scholar
    • Export Citation

  • Wang, B., R. Wu, and K.-M. Lau, 2001: Interannual variability of the Asian summer monsoon: Contrasts between the Indian and the western North Pacific–East Asian monsoons. J. Climate, 14, 4073–4090, doi:10.1175/1520-0442(2001)014<4073:IVOTAS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Wu, C.-H., and M.-D. Chou, 2012: Upper-tropospheric forcing on late July monsoon transition in East Asia and the western North Pacific. J. Climate, 25, 3929–3941, doi:10.1175/JCLI-D-11-00343.1.

    • Search Google Scholar
    • Export Citation

  • Wu, C.-H., W.-S. Kau, and M.-D. Chou, 2009: Summer monsoon onset in the subtropical western North Pacific. Geophys. Res. Lett., 36, L18810, doi:10.1029/2009GL040168.

    • Search Google Scholar
    • Export Citation

  • Wu, L., Z. P. Wen, R. H. Huang, and R. G. Wu, 2012: Possible linkage between the monsoon trough variability and the tropical cyclone activity over the western North Pacific. Mon. Wea. Rev., 140, 140–150, doi:10.1175/MWR-D-11-00078.1.

    • Search Google Scholar
    • Export Citation

  • Wu, R., 2002: Processes for the northeastward advance of the summer monsoon over the western North Pacific. J. Meteor. Soc. Japan, 80, 67–83, doi:10.2151/jmsj.80.67.

    • Search Google Scholar
    • Export Citation

  • Wu, R., and B. Wang, 2000: Interannual variability of summer monsoon onset over the western North Pacific and the underlying processes. J. Climate, 13, 2483–2501, doi:10.1175/1520-0442(2000)013<2483:IVOSMO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Wu, R., and B. Wang, 2001: Multi-stage onset of the summer monsoon over the western North Pacific. Climate Dyn., 17, 277–289, doi:10.1007/s003820000118.

    • Search Google Scholar
    • Export Citation

  • Yoneyama, K., and D. B. Parsons, 1999: A proposed mechanism for the intrusion of dry air into the tropical western Pacific region. J. Atmos. Sci., 56, 1524–1546, doi:10.1175/1520-0469(1999)056<1524:APMFTI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 956 597 84
PDF Downloads 270 43 3