THE INTENSITY VARIATION OF THE SUMMER INTERTROPICAL CONVERGENCE ZONE IN WESTERN NORTH PACIFIC AND ITS IMPACT ON TROPICAL CYCLONES

CAO Xi; CHEN Guang-hua; HUANG Rong-hui; CHEN Wen

Abstract:

Based on the satellite data from the National Oceanic and Atmospheric Administration and the NCEP/NCAR reanalysis data, the variation of the intensity of convection over the Intertropical Convergence Zone (ITCZ) in summer and its impacts on tropical cyclones are studied. In this paper, an intensity index of the ITCZ is proposed according to Outgoing Longwave Radiation (OLR) in the region of (5°–C20°N, 120°–C150°E) in the western North Pacific (WNP). Then strong and weak ITCZ years are classified and different variables during the strong/weak ITCZ years are analyzed. The composite results show that the ITCZ anomaly is connected to the general atmospheric circulation and SST distribution. In the strong ITCZ years, the subtropical anticyclone weakens and shifts northward. Besides, there is salient cyclonic anomaly at the low level and anticyclonic anomaly at the high level. SST patterns in the preceding winter resemble to those of La Niña. It could persist into the succeeding summer. However, it is opposite in the weak ITCZ years. The impact of the ITCZ anomaly on the tropical cyclone (TC) formation and track is also discussed. There are more TCs over the WNP (5°–C20°N, 120°–C150°E) in the strong ITCZ years and there is a significant increase in the northward recurving TCs. In the weak ITCZ years, fewer TCs occur and the frequency of the northwestward track is higher.

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CAO Xi, CHEN Guang-hua, HUANG Rong-hui, et al. THE INTENSITY VARIATION OF THE SUMMER INTERTROPICAL CONVERGENCE ZONE IN WESTERN NORTH PACIFIC AND ITS IMPACT ON TROPICAL CYCLONES [J]. Journal of Tropical Meteorology, 2014, 20(3): 193-201.

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THE INTENSITY VARIATION OF THE SUMMER INTERTROPICAL CONVERGENCE ZONE IN WESTERN NORTH PACIFIC AND ITS IMPACT ON TROPICAL CYCLONES

Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 China

Rev Recd Date: 2014-05-12

Abstract: Based on the satellite data from the National Oceanic and Atmospheric Administration and the NCEP/NCAR reanalysis data, the variation of the intensity of convection over the Intertropical Convergence Zone (ITCZ) in summer and its impacts on tropical cyclones are studied. In this paper, an intensity index of the ITCZ is proposed according to Outgoing Longwave Radiation (OLR) in the region of (5°–C20°N, 120°–C150°E) in the western North Pacific (WNP). Then strong and weak ITCZ years are classified and different variables during the strong/weak ITCZ years are analyzed. The composite results show that the ITCZ anomaly is connected to the general atmospheric circulation and SST distribution. In the strong ITCZ years, the subtropical anticyclone weakens and shifts northward. Besides, there is salient cyclonic anomaly at the low level and anticyclonic anomaly at the high level. SST patterns in the preceding winter resemble to those of La Niña. It could persist into the succeeding summer. However, it is opposite in the weak ITCZ years. The impact of the ITCZ anomaly on the tropical cyclone (TC) formation and track is also discussed. There are more TCs over the WNP (5°–C20°N, 120°–C150°E) in the strong ITCZ years and there is a significant increase in the northward recurving TCs. In the weak ITCZ years, fewer TCs occur and the frequency of the northwestward track is higher.

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[1]	WALISER D E, GAUTIER C. A satellite-derived climatology of the ITCZ[J]. J. Climate, 1993, 6(11): 2162-2174.
[2]	HUBERT L F, KRUEGER A F, WINSTON J S. The double Intertropical Convergence Zone-fact or fiction[J]. J. Atmos. Sci., 1969, 26(4): 771-773.
[3]	GODSHALL F A. Intertropical Convergence Zone and mean cloud amount in the tropical Pacific Ocean[J]. Mon. Wea. Rev., 1968, 96(3): 172-175.
[4]	XIE Yi-bing, CHEN Shou-jun, ZHANG Yi-liang, et al. A preliminarily statisti and synoptic study about the basic currents over southeastern Asia and the initiation of typhoons [J]. Acta Meteor. Sinica, 1963, 33(2): 206-217.
[5]	XIE Yi-bing, HUANG Ying-liang. A preliminary theoretical study about the instability of the waves along the Intertropical Convergence Zone [J], Acta Meteor. Sinica, 1964, 34(2): 198-210.
[6]	JIANG Shang-cheng. The climatic characteristics of the ITCZ all over the globe [J]. Acta Meteor. Sinica, 1988, 46(2): 241-245.
[7]	FAN Hui-jun, LI Xiu-fang. An analysis of the three-dimensional structure of ITCZ over NW Pacific [J]. Marine Forecast Serv., 1985, 2(2): 19-25.
[8]	LI Chong-yin, PAN Jing. Theinterannual variation of the South China Sea summer monsoon trough and its impact [J]. Chin. J. Atmos. Sci., 2007, 31(6): 1050-1058.
[9]	VINCENT E M, LENGAIGNE M, MENKES C E, et al. Interannual variability of the South Pacific Convergence Zone and implications for tropical cyclone genesis [J]. Clim. Dynamics, 2009, 36(9-10): 1881-1896.
[10]	ROBERTSON A, MECHOSO C. Interannual and interdecadal variability of the South Atlantic convergence zone[J]. Mon. Wea. Rev., 2000, 128(8): 2947-2957.
[11]	GRAY W M. Global view of the origin of tropical disturbances and storms [J]. Mon. Wea. Rev., 1968, 96(10): 669-700.
[12]	NEUMANN C J. Global overview, Global Guide to Tropical Cyclone Forecasting [M]. Geneva: Rep TCP-31 WMO/TD No 560, World Meteorological Organization, 1993: 220.
[13]	GRAY W M. Hurricanes: Their formation, structure and likely role in the tropical circulation. Meteorology over the Tropical Oceans [D]. Royal Meteorology Society, 1979: 155-218.
[14]	CHEN Lian-shou, DING Yi-hui. The conspectus of western Pacific trphoon [M]. Beijing: Science Press, 1979: 491.
[15]	DING Yi-hui, REITHER E R. Large-scale circulation conditions affecting the typhoon formation over the Western Pacific [J]. Acta Oceanol. Sinica, 1983, 5(5): 561-574.
[16]	WANG Hui, DING Yi-hui, HE Jin-hai. Influence of western North Pacific summer monsoon change on typhoon genesis [J]. Acta Meteor. Sinica, 2006, 64(3): 345-356.
[17]	LIU Ge, ZAHNG Qing-yun, SUN Shu-qing. A preliminary study on activities of tropical cyclones over the western North Pacific during the summer in 2006 [J]. Clim. Environ. Res., 2007, 12(6): 738-750.
[18]	LIU Ge, SUN Shu-qing, ZHANG Qing-yun, et al. Characteristics of the intraseasonal oscillation of intertropical convergence zone and its influence on the periodical tripical cyclogenesis [J]. Chin. J. Atmos. Sci., 2009, 33(4): 879-889.
[19]	SUN Shu-qing, LIU Ge, ZHANG Qing-yun. The influence of the circulation anomalies in the southern hemisphere on the tropical cyclone frequency in summer over ther western Pacific and its mechanism [J]. Chin. J. Atmos. Sci., 2007, 31(6): 1190-1200.
[20]	JIANG Le-yi, YING Ming. Analysis of anomalous frequency of tropical cyclone in east China [J]. Quart. J. Appl. Meteor., 2002, 13(1): 89-95.
[21]	ZHANG Guang-zhi, ZHANG Xian-gong, WEI Feng-ying. A study on the variations of annual frequency fro tropical cyclone in northwest Pacific during the last hunrd years [J]. J. Trop. Meteor., 1995, 11(4): 315-323.
[22]	LU Qiu-zhen, HU Bang-hui, WANH Xue-zhong, et al. Large scale circulation associated with interdecadal variation of typhoon activity over the western North Pacific [J]. J. Trop. Meteor., 2007, 23(6): 538-544.
[23]	WANG C C, CHOU C, LEE W L. Breakdown and reformation of the Intertropical Convergence Zone in a Moist Atmosphere [J]. J. Atmos. Sci., 2010, 67(4): 1247-1260.
[24]	PAN Jing, LI Chong-yin. Comparison of climate characteristics between two summer monsoon troughs over the South China Sea and India [J]. Chin. J. Atmos. Sci., 2006, 30(3): 377-390.
[25]	GU G, ZHANG C. Cloud components of the Intertropical Convergence Zone [J]. J. Geophys. Res., 2002, 107(D21): 4 565.
[26]	GILL, A. E. Some simple solutions for heat-induced tropical circulation [J]. Quart. J. Roy. Meteor. Soc., 1980, 106, 447-462.
[27]	CHAN J C L. Tropical cyclone activity in the Northwest Pacific in relation to the El Ni?o/Southern Oscillation phenomenon [J]. Mon. Wea. Rev., 1985, 113(4): 599-606. [27] CHEN T C, WENG S P, YAMAZAKI N, et al. Interannual variation in the tropical cyclone formation over the western North Pacific [J]. Mon. Wea. Rev., 1998, 126(4): 1080-1090.
[28]	CHEN T C, WENG S P, YAMAZAKI N, et al. Interannual variation in the tropical cyclone formation over the western North Pacific [J]. Mon. Wea. Rev., 1998, 126(4): 1080-1090.
[29]	LANDER M A. An exploratory analysis of the relationship between tropical storm formation in the western North Pacific and ENSO [J]. Mon. Wea. Rev., 1994, 122(4): 636-651.
[30]	WANG B, CHAN J C L. How strong ENSO events affect tropical storm activity over the western North Pacific [J]. J. Climate, 2002, 15(13): 1643-1658.
[31]	CHEN G, HUANG R. Influence of monsoon over the warm pool on interannual variation on tropical cyclone activity over the western North Pacific [J]. Adv. Atmos. Sci., 2008, 25(2): 319-328.

THE INTENSITY VARIATION OF THE SUMMER INTERTROPICAL CONVERGENCE ZONE IN WESTERN NORTH PACIFIC AND ITS IMPACT ON TROPICAL CYCLONES

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