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1 Jour. Korean Earth Science Society, v. 29, no. 1, p , February 2008 (w ) kt : ENSO w Áw * w y lw, Ÿ 30 On the Relationship between Typhoon Intensity and Formation Region: Effect of Developing and Decaying ENSO Sae-Rom Jang and Kyung-Ja Ha* Division of Earth Environmental System, Pusan National University, Busan , Korea Abstract: This study investigates the influence of the developing and decaying El Niño-Southern Oscillation (ENSO) on the relation between typhoon intensity and its formation. From the long-term data of 57 years (1950~2006), we first defined the developing El Niño years and the neutral years. During the developing El Niño years, the typhoon intensity has a strong relationship with formation region of the tropical cyclone, which results in an increase of the accumulated cyclone energy and intensity of energy of typhoon. During the developing El Niño year based on Niño 3.4 SST, the locations for the formation of the category 4+5 typhoon move to the eastward region. The genesis potential function and the low-level cyclonic vorticity have an important role on the formation of strong tropical cyclones, which eventually develop as a typhoon class. In this study, the dynamic potential (DP) function (Gray, 1977) and EOF 1 and EOF 2 time series (RMM 1 and RMM 2) of real-time multivariate MJO (Wheeler and Hendon, 2004) are used to measure the genesis potential and the low-level cyclonic vorticity, respectively. To investigate the influence of the developing and decaying ENSO, we defined the Type I case of the decaying El Niño that turnovers to La Niña, and the Type II case of the recovering years to the neutral condition. During the decaying El Niño years as Type I, the locations of the strong DP, RMM 1 and RMM 2 move to the westward more prominently to induce retard of the strong typhoon developing.,fzxpset typhoon, intensity, formation, ENSO : El Niño-Southern Oscillation(ENSO) w kt kt r l 2006 ¾» w, w w w. w kt kt ùküš» kt ƒ ƒw. Niño 3.4 w» w w, category 4+5 w w kt e ùkù. kt w wd» z kt w w w w» w ƒ. w [DP, Gray(1977)] MJO EOF w w RMM 1, RMM 2(Wheeler and Hendon, 2004) w kt w» wd» z d w. ENSOƒ w w w w w» w ƒ ù ÿ y Type I w z w Type II w. Type I» DP RMM1, RMM2 x w e ùkù w kt k. kt,,, ENSO *Corresponding author: kjha@pusan.ac.kr Tel: Fax:

2 30 Áw (El Niño) ks ù ³ w, w»-w y y» y w eš. Gray(1984) ƒ x f w e š, Hastings(1990) û ks w» ƒ p (anti-el Niño) w y ƒw, Anthes(1982) ks w k t ƒ w š šw. p, 1997 / 98 w x ƒ w, w w t w p ƒ š (Takayabu et al., 1999) / 98 x mw ENSO»z l, w ENSO w ƒ (Saji et al., 1999; Webster et al., 1999; Yu and Rienecker, 2000; Wang and McPhanden, 2001). w, 1997/98 x w z ks w st ƒ»z y p ùkùš (Lander and Guard, 2001; Allan and Komar, 2002). ks w kt ENSO w w mw. p, kt z ENSO x ƒ, ENSO w w š ³ (Chan, 2000; Chen et al., 1998; Wang and Chan, 2002). w, w w w kt û e w w ùkù, w ks» ƒ ƒw x (Wang and Chan, 2002; Clark and Chu, 2002).» w ƒ kt z. ù, ENSOƒ kt e w w w w š. Accumulated Cyclone Energy(ACE) ENSO index mw kt ENSO (Camargo and Sobel, 2005). ENSO w kt y kt y w w mw. w, ENSOƒ wš w ùkù kt kt y w w., kt r š, mw ENSO kt e w ww š w. w kt œ Joint Typhoon Warning Center(JTWC) œw, 1950 l 2006 ¾ 57 ks w kt 6 e t œw. kt Saffir-Simpson scale» t 64 knots ( w TD-TS) knots ( w category 1+2+3), t 114 knots ( w category 4+5) w w. w ƒ w. British Atmospheric Data Centre (BADC) œw HadISST 1870 l x ¾».» l ¾, s 1 o Ü1 o. National Centers for Environmental Prediction(NCEP) œw Optimum Interpolation Sea Surface Temperature analysis version 2(OIv2 SST), ü (Reynolds and Smith, 1994) w w, l x ¾ ƒ œ š. ƒ œ s 1 o Ü1 o HadISST w. Outgoing Longwave Radiation (OLR) National Oceanoaphic and Atmospheric Administration(NOAA) w,» NCEP œw w. ENSO j w w» w 1950 l 2006 ¾» w(neutral year) w(developing El Niño year) w w. w w» w x ƒ»,

3 kt &/40 w 31 Fig. 1. Schematic diagram of Oceanic Niño Index for the developing and decaying El Niño. NCEP œw Oceanic Niño index (ONI)ƒ +0.5 C 5 o x ³ w, 0.5 o C 5 ÿ x ³ w. ONI Extended Reconstructed Sea Surface Temperature version 2(ERSST.v2) (Smith and Reynolds, 2004) Niño 3.4 (5 o N- 5 o S, 120 o W-170 W) w o 3 s³,»z 1971 l 2000 ¾ 30» w. ENSO j š w» w, w w ENSOƒ w DJF» s š(rasmusson and Garpenter, 1982), w ENSO j š w» w DJF» w w wš, z w w ùkü (Fig. 1). š» kt 7 l 10 ¾ (JASO)» w. w,» w y Type I Type II w. Type I» Niño w ƒ yw ÿ x w, Type II» Niño Fig. 2. Schematic diagram of Oceanic Niño Index for Type and TypeG II. w yƒ w š w ƒ w (Fig. 2). w» mw w Table 1 ùkü. kt kt p ENSO w kt kt p 1950 l 2006 ¾» w k t w TD-TS, category 1+2+3, category 4+5 w w kt kt Fig. 3 ùkü. kt z 2.5 o Ü2.5 o w kt z w ùkü.» 57 w k t r kt w 110 o E-180 o E, 5 o N-30 o N w w (Fig. 3a). w, w, ƒ w kt û e e w š (Fig. 3b, 3c, 3d). w w s³ mw w ùkû y w, kt s³ o E, o N w, kt TD-TS o E, o N, category Table 1. The classification of the Neutral, developing El-Niño, type I, and type II years Neutral developing El-Niño Type I Type II Case Years 1952, 1953, 1958, 1959, 1960, 1962, 1966, 1978, 1979, 1980, 1981, 1985, 1989, 1990, 1992, 1993, 1996, 2001, 2003, 2005 (20 years) 1951, 1957, 1963, 1965, 1968, 1969, 1972, 1976, 1977, 1982, 1987, 1991, 1994, 1997, 2002, 2004, 2006 (17 years) 1963/1964, 1969/1970, 1972/1973, 1982/1983, 1987/1988, 1994/1995, 1997/1998 (7 cases) 1951/1952, 1957/1958, 1965/1966, 1977/1978, 1991/1992, 2002/2003, 2004/2005 (7 cases)

4 32 Áw Fig. 3. The total number of Typhoon occurrence for (a) total, (b) TD-TS, (c) category 1+2+3, and (d) category 4+5 during the period from 1950 to The X denotes the mean locations of formation of tropical depression o E, o N, category o E, o N ùkù.» w. TD-TS s³ w 4.76 o, category 4+5 s³ 8.43 o š. ƒ ƒƒ 2228, 1994 ³ s ƒ

5 kt &/40 w 33 Fig. 4. ACE per year in the period from 1950 to The horizontal lines show the 25 th and 75 th percentiles (dashed) and median (solid). w, 95% wš. mw kt kt ƒ š w, kt kt ƒ wš w. kt ENSO kt y ENSO r» w kt ùkü Accumulated Cyclone Energy(ACE) y w ÿw, w w wì ùkü (Fig. 4). ACE kt,, w (Bell et al., 2000). ACE = Σ(V max 2/10 4 ) (10 4 kt 2 ) (1)» V max 6 t, TD k w w 34 knots w t w. ƒ mw 25%, w 25% ùkü, w w w 50%ƒ w, 25% w w 14w 8wƒ w, 5wƒ w, w w ÿ w ùkû, mw w ACEƒ w ÿ w w j. r kt ENSOƒ ƒ š w, k t ENSO r» w 7 l 10 ¾ ACE ENSO Fig. 5. Lag-lead correlation coefficients between the time series of ACE (JASO) and monthly Niño indices. The reference ACE displays the thick gray bar, year 1 (year +1) denotes the year before (after) the reference Niño indices. The horizontal dashed lines indicate the 95%, 99% confidence levels, respectively. ƒ (Fig. 5).» ACE w w» z mw t w, ENSO š ùkü. w w ENSO ACE š w, ù kü» w w w w l ƒ. Niño 1+2 index w 3 ƒ š, Niño 3, Niño 4, Niño 3.4 index w l ¾ 99%. mw ƒ w kt š s ENSO ƒ š w. kt, kt, š ENSO mw kt kt ENSO r.» ENSO kt w w š (Camargo and Sobel, 2005). w kt w ENSO e w r wš. k kt

6 34 Áw Fig. 6. The scattered diagram of the longitude on typhoon formation and maximum wind during the life cycle for (a) the period , (b) developing and decaying El Niño years, (c) developing El Niño years, (d) decaying El Niño years. kt y w ENSO w wš w., 1950 l 2006 ¾» w w sww», w» wš w» w kt kt» t s ùkü (Fig. 6). w w sww» w kt» ùkü w w kt e ú ƒ¾ š w kt e e p t x ƒ ùkù (Fig. 6a, 6b). w w t w t x ƒ w ùkùš š, w w 0.36 ƒ ùkü (Fig. 6c)., kt kt ƒ ùkù w» w kt kt wš w. kt w e w ƒ (Holland, 1997; Wu and Lau, 1992), k kt w e kt (Energy of Typhoon, EOT) w. EOT Gray(1977) kt Seasonal Genesis Parameter(SGP) k w. w SGP kt w e 6ƒ y wš, EOT SGP kt w w w w w,

7 kt &/40 w 35 Fig. 7. The time series of the maximum wind and the EOT for strong wind cases in Fig. 6c during the developing El Niño years.. EOT = (SST 26) (1/(VWS+3)) (2)», SST kt» ùkü w, VWS 850 hpa 200 hpa ùkü., k t kt t w EOT w w. w kt kt t x ƒ w kt w kt w kt w kt t EOT ùkü (Fig. 7, Fig. 8). w kt t 140 knots, 170 o E w, w kt t 50 knots w, 120 o E w w ƒƒ 6 w. w kt ( y, y, y, y, y, y kt) r kt» EOT j ùkù w p Fig. 7a w w y kt p w ùkùš, EOT w t w wš (Fig. 7). w w kt ( y, y, y, y, y, y kt)

8 36 Áw Fig. 8. Same as Fig. 7 except for weak wind cases. EOT t š (Fig. 8). mw EOT kt ùkü, Fig. 6 w kt kt ƒ w y w ùkû y w. ¾ w ùkù kt k t r, w» w w w w kt s³ z m p w (Table 2). w w kt category 4+5 w w w kt z š, w s ³ e ƒ û ùkù, kt w TD-TS o E, o N, category o E, o N, category o E, o N w kt, e w mw w Table 2. The mean statistics of Typhoon for the Neutral years and the developing El-Niño years Neutral developing El-Niño Total (No. yr 1 ) TD-TS (No. yr 1 ) category (No. yr 1 ) category 4+5 (No. yr 1 ) longitude ( o E) latitude ( o N)

9 kt &/40 w 37 Fig. 9. Lag-lead correlation coefficients between time series of mean typhoon formation (JASO) with monthly Niño indices. The reference mean typhoon formation displays the thick gray bar, Year -1 (year +1) denotes the year before (after) the reference Niño indices. The horizontal dashed lines indicate the 95%, 99% confidence levels, respectively. kt kt w. kt ùkü ACE ENSO š, kt ENSOƒ ƒ w l ¾ š y w (Fig. 5), w kt ƒ kt ENSO š w. 7 l 10 ¾» w kt s³ ENSO ƒ, w w» z mw t w (Fig. 9). y ql Fig. 5 w y š, ww Niño 1+2 index kt 95% š š ùkù» w 99% š. w Niño 3, Niño 4, Niño 3.4 index w l w ¾ kt š 99% š (Fig. 9). mw ƒ w kt w š s ENSO ƒ š w. kt e ENSO w w w» x mw w» w mw (Bjerknes, 1966; Lindzen and Nigam, 1987)., w kt» x w sƒ š (Emanuel, 1987; Evans, 1993). w w» x r w ƒ., Michaels et al.(2006)» w ƒ w e, w ƒ o C w ƒ x f.» w w w wš, kt e w w w š w. Gray(1977) kt ƒ y w, mw ƒ seasonal genesis parameter(sgp). SGP dynamic potential (DP) w thermal potential(tp) w w, ƒ w 3ƒ y mw w. DP (Coriolis parameter), wd (Vorticity parameter), (Vertical shear parameter), TP w (Ocean energy parameter), (Moist stability parameter), d «(Humidity parameter)ƒ w w.», TP SGP v w, kt k ùkü» w, DP ƒ SGP j ü (McBride, 1981). DP w kt kt w w w w. DP (Gray, 1977). DP = (f)(ζ r +5)[(1/VWS+3)] (3) f (units of s 1 ), ζ r 1000 hpa (10 6 s 1 ), VWS 850 hpa 200 hpa (m s ) 1 ùkü, mw

10 38 Áw Fig. 10. Dynamic potential for (a) the developing El-Niño years, (b) the Neutral years, and (c) difference (a-b) in October. Dots denote cyclogenesis for TD-TS (triangle), category (square), and category 4+5 (circle). DP ƒ w ƒ»» wd wš w yw w. w ƒ w w kt e w w» w kt ƒ 7 l 10 ¾» DP œ kt w, w w ƒ ƒ w 10 ùkü (Fig. 10). kt DPƒ ƒ w, 7 10 w DPƒ w w wš š kt w DP s ú kt ùkù, p category 4+5 w w w k t (Fig. 10). ùkü mw w w kt DPƒ j ùkù ƒ wš wd j ùkù kt w» w (Fig. 10).

11 kt &/40 w 39 Fig. 11. (RMM 1, RMM 2) phase space points for all available days in JASO season for the developing El Niño years (black dots) and neutral years (open circles) (similar to Fig. 13 of Wheeler and Hendon (2004)). Eight defined regions of the phase space are labeled, as is the region considered to signify weak MJO activity. Also labeled are the approximate locations of the enhanced convective signal of the MJO for that location of the phase space. MJO p Madden-Julian Oscillation(MJO; Madden and Julian, 1972) ENSO j w w (Kessler and Kleeman, 2000; Zhang and Gottschalck, 2002; Seo and Xue, 2005). DP m w ENSO w» w y w kt w š w. w, kt ENSO ƒ MJO w kt w e, Liebmann et al.(1994) kt w MJO w w., MJO w ƒ w t ƒ w û ƒƒ» z w. d š» z w š, w wš d w kt y w y x (Rui and Wang, 1990). MJO p w Real-time Multivariate MJO(RMM) w. RMM» w z (15 o S-15 o N) s³ 850 hpa 200 hpa, d OLR mw x w k (Wheeler and Hendon, 2004). PC 1, PC 2 RMM 1 RMM 2, MJO RMM w 8 w., MJO ENSO w» w RMM (RMM 1 2 +RMM 2 2 ) w MJO r ù, MJO ENSO ùkù ( ). 200 hpa w MJO w š, MJO ENSO w w Slingo et al.(1999) ew. w, Hendon et al.(1999) Kessler(2001) w ks w MJO p 20 o w ùkû x. p kt e w r» w kt RMM w. Fig. 11 w w 7 l 10 ¾ w kt RMM ùkü, w MJO ùkü. ùkü w kt RMM š ùkü w, w MJO ks (phase 6, 7, 8) w ùkù ƒ, w w (Maritime Continent; phase 4, 5, 6) w ùkû. mw k t» w MJOƒ e w MJOƒ wš š w, ³ y w w kt w. ENSO kt p ENSO w p z» ÿ x

12 40 Áw Fig. 12. Dynamic potential for (a) the Type I, (b) the Type II, and (c) difference (a-b) the developing El Niño years in September. Dots denote cyclogenesis for TD-TS (triangle), category (square), and category 4+5 (circle). y w z w Type I Type II w w. Type I Type II ENSO j kt p w MJO p mw wš w., Type I Type II w w w p r. kt kt w w r, Type I e w ƒ t ƒ Type II w. 7 l 10 ¾ DP kt r, 7, 9, 10 j ƒ 9 Type I Type IIƒ, Type I DP j ùkùš kt w e ú w kt (Fig. 12a, 12b). j ùkù e Type I Type II 20 o N w ùkù š 10 o N w ùk ù p (Fig. 12c). w, MJO p r, phase 7, 8 w ùkù ( ). ¾ r w Type I Type II

13 kt &/40 w 41 Fig. 13. Same as Fig. 12 except for the decaying El Niño years. 9 w» j š, Type I kt e e w p ùkü. ENSO w p ENSO w p w Type I Type II w w w p w. w kt kt ƒ Type I Type II , Type kt kt ƒ w» û ùküš. w w 7 l 10 ¾ DP k t r, w w 9 Type I Type IIƒ, Type II DP j ùkùš kt w ú ¾ y, Type I DP ùkùš kt w e š ƒ w kt (Fig. 13a, 13b). p w Type I Type II 120 o E l ú ¾ j ùkù š y w (Fig. 13c). w s³ kt z mw y w

14 42 Áw, s³ kt z 28.86z 28.71z ƒ, Type I category 4+5 w w kt s ³ 5.71z Type II 7.57z w kt z ƒ š, s³ Type I o E, o N š Type II o E, o N j. w p RMM ùkù, Type I MJO w (phase 4, 5, 6) w ùkù p. mw w w w Type I Type II w w» w, y w Type I w ƒ Type II w kt e e š kt w w ùkù w kt wš. m ENSOƒ wš w j w kt kt r l 2006 ¾ 57» ENSO w s DJF» w w wš z w w wš, w w w r,» El Niño w ƒ yw ÿ x w Type I, w w y mw w z w Type II w ENSO j w w. kt t TD-TS, category 1+2+3, category 4+5 w,» w kt m s³ r ƒ j û e e p mw kt kt w. w p w ùkû, w kt w kt w kt EOT t r kt ƒ ƒ w y w y w. w, kt ENSO ƒ w w w l ¾ š, kt ENSO w l w ¾ ENSOƒ w» l s ùkü»¾ ƒ š y w. w ENSO w ùkù w» w w ùkü DP MJO p ùkü RMM w. w DP kt w w j ùkùš mw kt w» w ƒ š š, RMM mw MJO r w MJOƒ e wš» z w e e w w. k Type I Type II w w ùk ù kt kt p ƒƒ w. Type II w Type I w kt kt ùkù, p w ƒ j ùkù., Type» w y w y DP MJO e kt w e ƒ û ùkù. mw ENSO j w» w MJO ³ y y w kt kt w eš. y w» (Ecotechnopia 21 project) BK21 2. š x Allan, J.C. and Komar, P.D., 2002, Extreme Storms on the Pacific Northwest Coast during the El Niño and La Niña. Journal of Coastal Research, 18 (1), Anthes, R.A., 1982, Tropical cyclones: Their evolution,

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