Asia-Pacific Journal of Atmospheric Sciences

Korean Meteorological Society (한국기상학회)
권호 표지

A Study on the Intensity Change of Typhoon Nakri (0208) - Observation and GDAPS Data Analysis

태풍 나크리(0208)의 강도변화에 관한 연구 : 관측과 GDAPS 모델 자료 분석

Kim, Baek-Jo;Cho, Chun-Ho;Chung, Hyo-Sang;Shin, Sun-Hee
김백조;조천호;정효상;신선희

  • Published : 2005.10.31
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Abstract

The characteristics of environmental influences and lower tropospheric vertical structure over ocean associated with the intensity change of typhoon Nakri were investigated using the observation data by two Aerosondes and GDAPS(Global Data Analysis and Prediction System) data. Typhoon Nakri (0208), which formed as a Tropical Storm (TS) at about 400 km southwest of Taiwan on 1800UTC July 8, 2002, has experienced an intensity change from Tropical Storm (TS) on 1200UTC 12 July to Tropical Depression (TD) on 1200UTC 13 July. The evolutions of 200-850 hPa vertical wind shear and 200 hPa eddy relative angular momentum flux convergence (EFC) computed from the GDAPS analysis data showed that vertical wind shear exceeded 10 m $s^{-1}$ from 1200UTC 12 July to 0000UTC 13 July. Positive values of EFC were larger during the period of 1800UTC 12 July to 0600UTC 13 July than other times. This analysis indicates that typhoon Nakri interacts with the upper tropospheric trough, so it becomes weak rapidly. We also found from the Aerosonde observations that lower tropospheric vertical structure for about three hours before the typhoon weakened was different from that of other times. That is, the inversion base and top were much lower than the other periods but its intensity was stronger. Also, northwesterly was appeared at altitude between 1.5 km and 3.5 km. It means that the southward movement of low at 850 hPa before the extension of western North Pacific subtropical high affects lower tropospheric vertical structure over ocean ahead of typhoon. This southward movement might be regarded as a precursor process of typhoon-trough interaction.

2002년 7월 8일 1800UTC에 대만 남서쪽 400 km 부근에서 열대성 폭풍으로 발생한 태풍 Nakri (0208)는 7월 12일 1200UTC의 열대성 폭풍에서 7월 13일 1200UTC의 열대성 저압부로 강도변화를 경험하였다. 본 연구에서는 태풍 Nakri의 강도변화와 관련된 주변 기상요소의 발전양상과 해양상 하부 대류권 대기구조 특성을 에어로존데 관측자료와 GDAPS 분석자료를 이용하여 조사하였다. GDAPS 분석값을 이용하여 계산된 연직바람시어와 EFC의 발전 양상에서 7월 12일 1200UTC에서 7월 13일 0000UTC사이에 연직시어가 10 m $s^{-1}$이상으로 나타났고, 7월 12일 1800UTC에서 7월 13일 0600UTC사이의 EFC의 양의 값이 다른 기간들에 비해 크게 나타났다. 이같은 분석결과는 태풍 Nakri가 상층 대류권 기압골과 상호작용을 통하여 약화되었음을 반영한다. 에어로존데 관측으로부터 태풍이 급격히 약화되기 3시간 전 하부 대류권 대기연직구조 (온도 및 바람)가 다른 기간들과 다르게 나타남을 밝혔다. 즉, 역전층의 상부와 하부 고도가 다른 기간들에 비해 아주 낮고 그 강도는 강하였으며, 북서풍 계열이 고도 1.5 km-3.5 km 사이에 나타났다. 이는 북서태평양 고기압이 확장하기 전에 850 hPa면의 저기압의 남하가 태풍 전면 하부 대류권 구조에 영향을 주었음을 의미한다. 따라서, 이러한 저기압 남하는 태풍-기압골 상호작용의 전조과정으로 고려되어 질 수 있다.

Keywords

References

  1. Barrett, 1999 : Estimating the amount of rainfall associated with tropical cyclones using satellite techniques, WMO technical document, NO. TCP-42, pp. 290
  2. Burpee, R. W., D. G. Marks, and R. T. Merrill, 1984 : An assessment of Omega dropwindsonde data in track forecasts of hurricane Debby (1982). Bull. Amer. Meteor. Soc., 65, 1050-1058 https://doi.org/10.1175/1520-0477(1984)065<1050:AAOODD>2.0.CO;2
  3. Burpee, R. W., J. L. Franklin, S. J. Lord, R. E. Tuleya, and S. M. Aberson, 1996 : The impact of Omega dropwindsondes on operational hurricane track forecast models, Bull. Amer. Meteor. Soc., 77, 925-933 https://doi.org/10.1175/1520-0477(1996)077<0925:TIOODO>2.0.CO;2
  4. DeMaria, M., J.-J. Baik, and J. Kaplan, 1993: Upper-level eddy angular momentum fluxes and tropical cyclone intensity change. J. Atmos. Sci., 50, 1133-1147 https://doi.org/10.1175/1520-0469(1993)050<1133:ULEAMF>2.0.CO;2
  5. Holland, G. J., T. McGeer, and H. Youngren, 1992 : Autonomous Aerosondee for economical atmospheric soundings anywhere on the globe. Bull. Amer. Meteor. Soc., 73, 1987-1998 https://doi.org/10.1175/1520-0477(1992)073<1987:AAFEAS>2.0.CO;2
  6. Holland, G. J., and R. T. Merrill, 1984: On the dynamics of tropical cyclone structural changes. Quart. J. Roy. Meteor. Soc., 110, 723-745 https://doi.org/10.1002/qj.49711046510
  7. Holland, G. J., and Coauthors, 2001: The aerosonde robotic aircraft: A new paradigm for environmental observations. Bull. Amer. Meteor. Soc., 82, 889-902 https://doi.org/10.1175/1520-0477(2001)082<0889:TARAAN>2.3.CO;2
  8. Kim, B. J., H. S. Chung, C. H. Cho and J. H. Kim, 2003 : Structural Features of Typhoon RUSA's Center, Vaisala News, 162, 4-7
  9. Molinari, J., and D. Vollaro, 1989: External influences on hurricane intensity. Part I: Outflow layer eddy momentum fluxes. J. Atmos. Sci., 46, 1093-1105 https://doi.org/10.1175/1520-0469(1989)046<1093:EIOHIP>2.0.CO;2
  10. Molinari, J., and D. Vollaro, 1990: External influences on hurricane intensity. Part II: Vertical structure and response of the hurricane vortex. J. Atmos. Sci., 47, 1902-1918 https://doi.org/10.1175/1520-0469(1990)047<1902:EIOHIP>2.0.CO;2
  11. Molinari, J., 1993: Environmental controls on eye wall cycles and intensity change in Hurricane Allen (1980). Tropical Cyclone Disasters, J. Lighthill, Z. Zhemin, G. Holland, and K. Emanuel, Eds., Peking University Press, 328-337
  12. Nakazawa, T., 2001 : Typhoon Hunter 2001 by Aerosonde in Japan, Proceedings of International Workshop on Observation and Forecasting of Severe Weathers associated with KEOP (IWOF-KEOP), Jeju, Korea, Nov. 13-14, 2001, 91-94
  13. Pfeffer, R. L., and Challa M., 1981: A numerical study of the role of eddy fluxes of momentum in the development of Atlantic hurricanes. J. Atmos. Sci., 38, 2393-2398 https://doi.org/10.1175/1520-0469(1981)038<2393:ANSOTR>2.0.CO;2
  14. Soddell, J. R., K. McGuffie and G. J. Holland, 2004 :Intercomparison of atmospheric soundings from the Aerosonde and radiosonde, J. Appl. Meteor., 43, 1260-1269 https://doi.org/10.1175/1520-0450(2004)043<1260:IOASFT>2.0.CO;2
  15. Tuleya, R. E. and S. J. Lord, 1997 : The impact of dropwindsonde data on GFDL hurricane model forecasts using global analysis. Weather and Forecasting, 12, 307-323 https://doi.org/10.1175/1520-0434(1997)012<0307:TIODDO>2.0.CO;2
  16. Zehr, R. M., 1992: Tropical cyclogenesis in the western North Pacific. NOAA Tech. Rep. NESDIS 61, 181 pp