African easterly jet: Barotropic instability, waves, and cyclogenesis

Journal of Climate

Volumn 25, Issue 5, 2012, Pages 1489-1510

  Wu, Man Li C ^a   Reale, Oreste ^a,c   Schubert, Siegfried D ^a   Suarez, Max J ^a   Thorncroft, Chris D ^b  

^a NASA GODDARD SPACE FLIGHT CENTER   (United States)

^b STATE UNIVERSITY OF NEW YORK   (United States)

^c UNIVERSITIES SPACE RESEARCH ASSOCIATION   (United States)

Author keywords

Africa; atmospheric; Cyclogenesis cyclolysis; Jets; Precipitation; Waves

Indexed keywords

AFRICA; AFRICAN EASTERLY JET; AFRICAN EASTERLY WAVES; BAROTROPIC; CYCLOGENESIS; CYCLOGENESIS/CYCLOLYSIS; DATA SETS; EXTRATROPICAL; FORCINGS; GLOBAL PRECIPITATION CLIMATOLOGY PROJECTS; HILBERT HUANG TRANSFORMS; INSTABILITY CONDITION; MEAN FLOW; REANALYSIS; RESEARCH AND APPLICATION; RETROSPECTIVE ANALYSIS; SEA SURFACE TEMPERATURE (SST); SEASONAL MEAN; SEASONAL PRECIPITATIONS; TROPICAL CYCLOGENESIS; TROPICAL CYCLONE; TROPICAL STORMS; VERTICAL SHEAR;

ATMOSPHERIC MOVEMENTS; ATMOSPHERICS; JETS; PRECIPITATION (CHEMICAL); SPECTRUM ANALYSIS; TROPICS; WAVES;

SHEAR FLOW;

ATMOSPHERIC CIRCULATION; ATMOSPHERIC STRUCTURE; BAROTROPIC INSTABILITY; CLIMATE FORCING; CYCLOGENESIS; EASTERLY WAVE; JET FLOW; MONSOON; SEA SURFACE TEMPERATURE; SPECTRAL ANALYSIS; STORM; TRANSFORM;

AFRICA; ATLANTIC OCEAN; ATLANTIC OCEAN (TROPICAL);

EID: 84858253815     PISSN: 08948755     EISSN: None     Source Type: Journal    
DOI: 10.1175/2011JCLI4241.1     Document Type: Article

References (56)

1. Adler, R. F., and Coauthors, 2003: The Version 2 Global Precipitation Climatology Project (GPCP) monthly precipitation analysis (1979-present). J. Hydrometeor., 4, 1147-1167.
2. Agusti-Panareda, A., A. Beljaars, C. Cardinali, I. Genkova, and C. Thorncroft, 2010: Impacts of assimilating AMMA soundings on ECMWF analyses and forecasts. Wea. Forecasting, 25, 1142-1160.
3. Aiyyer, A., and C.D. Thorncroft, 2006: Climatology of vertical wind shear over the tropical Atlantic. J. Climate, 19, 2969-2983.
4. Arnault, J., and F. Roux, 2009: Case study of a developing African easterly wave during NAMMA: An energetic point of view. J. Atmos. Sci., 66, 2991-3020.
5. Asnani, G. C., 2005: Tropical Meteorology. 2nd rev. ed., Vols. 1-3, Indian Institute of Tropical Meteorology, 2241 pp.
6. Bosilovich, M. G., and Coauthors, 2006: NASA's Modern Era Retrospective-Analysis for Research and Applications. Variations, No. 4, U.S. CLIVAR, Washington, DC, 5-8.
7. Bosilovich, M. G., and Coauthors, cited 2008: NASA's Modern Era Retrospective-Analysis for Research and Applications: Integrating earth observations. [Available online at http://www.earthzine.org/2008/09/26/nasas-modern-era-retrospective-analysis.]
8. Cook, K., 1999: Generation of the African easterly jet and its role in determining West African precipitation. J. Climate, 12, 1165-1184.
9. De Felice, P., A. Viltard, D. Monkam, and C. Ouss, 1990: Characteristics of North African 6-9 day waves during summer 1981. Mon. Wea. Rev., 118, 2624-2633.
10. De Felice, P., A. Viltard, and J. Oubuih, 1993: A synoptic-scale wave of 6-9-day period in the Atlantic tropical troposphere during summer 1981. Mon. Wea. Rev., 121, 1291-1298.
11. Diedhiou, A., S. Janicot, A. Viltard, and P. de Felice, 1998: Evidence of two regimes of easterly waves over West Africa and the tropical Atlantic. Geophys. Res. Lett., 25, 2805-2808.
12. Diedhiou, A., S. Janicot, A. Viltard, P. de Felice, and H. Laurent, 1999: Easterly wave regimes and associated convection over West Africa and tropical Atlantic: Results from the NCEP/NCAR and ECMWF reanalyses. Climate Dyn., 15, 795-822.
13. Done, J. M., G. J. Holland, and P. J. Webster, 2010: The role of wave energy accumulation in tropical cyclogenesis over the tropical North Atlantic. Climate Dyn., 36, 753-767.
14. Ferreira, R. N., and W. H. Schubert, 1997: Barotropic aspects of ITCZ breakdown. J. Atmos. Sci., 54, 261-285.
15. Goldenberg, S. B., and L. J. Shapiro, 1996: Physical mechanisms for the association of El Niño and West African rainfall withAtlanticmajor hurricane activity. J. Climate, 9, 1169-1187.
16. Hall, N. M. J., G. N. Kiladis, and C. D. Thorncroft, 2006: Threedimensional structure and dynamics of African easterly waves. Part II: Dynamical modes. J. Atmos. Sci., 63, 2231-2245.
17. Hopsch, S. B., C. D. Thorncroft, K. Hodge, and A. Aiyyer, 2007: West African storm tracks and their relationship to Atlantic tropical cyclones. J. Climate, 20, 2468-2483.
18. Hopsch, S. B., C. D. Thorncroft, and K. R. Tyle, 2010: Analysis of African easterly wave structures and their role in influencing tropical cyclogenesis. Mon. Wea. Rev., 138, 1399-1419.
19. Hsieh, J.-S., and K. Cook, 2005: Generation of African easterly wave disturbances: Relationship to the African easterly jet. Mon. Wea. Rev., 133, 1311-1327.
20. Hsieh, J.-S., and K. Cook, 2008: On the instability of the African easterly jet and the generation of African waves: Reversal of the potential vorticity gradient. J. Atmos. Sci., 65, 2130-2151.
21. Huang, N. E., and S. S. P. Shen, Eds., 2005: Hilbert-Huang Transform and its Applications. Interdisciplinary Mathematical Sciences Series, Vol. 5, World Scientific, 311 pp.
22. Huang, N. E., Z. Shen, and S. R. Long, 1999: A new review of nonlinear water waves: The Hilbert spectrum. Annu. Rev. Fluid Mech., 31, 417-457.
23. Huang, N. E., and Coauthors, 1998: The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis. Proc. Roy. Soc. London, 454A, 903-995.
24. Janicot, S., F. Mounier, S. Gervois, B. Sultan, and G. Kiladis, 2010: The dynamics of the West African monsoon. Part V: The detection and role of the dominant modes of convectively coupled equatorial Rossby waves. J. Climate, 23, 4005-4024.
25. Kanamitsu, M., W. Ebisuzaki, J. Woollen, S.-K. Yang, J. J. Hnilo, M. Fiorino, and G. L. Potter, 2002: NCEP-DOE AMIP-II Reanalysis (R-2). Bull. Amer. Meteor. Soc., 83, 1631-1643.
26. Kiladis, G. N., C. D. Thorncroft, and N. M. J. Hall, 2006: Threedimensional structure and dynamics of African easterly waves. Part I: Observations. J. Atmos. Sci., 63, 2212-2230.
27. Kistler, R., and Coauthors, 2001: The NCEP-NCAR 50-Year Reanalysis: Monthly means CD-ROM and documentation. Bull. Amer. Meteor. Soc., 82, 247-267.
28. Klotzbach, P. J., 2010: On the Madden-Julian Oscillation-Atlantic hurricane relationship. J. Climate, 23, 282-293.
29. Kossin, J., S. J. Camargo, andM. Sitkowski, 2010: Climatemodulation of North Atlantic hurricane tracks. J. Climate, 23, 3057-3076.
30. Krichak, S. O., P. Alpert, and M. Dayan, 2004: The role of atmospheric processes associated with Hurricane Olga in the December 2001 floods in Israel. J. Hydrometeor., 5, 1259-1270.
31. Kuo, H.-L., 1949: Dynamic instability of two-dimensional nondivergent flow in a barotropic atmosphere. J.Meteor., 6, 105-122.
32. Leroux, S., and N. M. J. Hall, 2009: On the relationship between African easterly waves and the African easterly jet. J. Atmos. Sci., 66, 2303-2316.
33. Leroy, A., and M. C. Wheeler, 2008: Statistical prediction of weekly tropical cyclone activity in the Southern Hemisphere. Mon. Wea. Rev., 136, 3637-3654.
34. Madden, R. A., and P. R. Julian, 1971: Detection of a 40-50 day oscillation in the zonal wind in the tropical Pacific. J. Atmos. Sci., 28, 702-708.
35. Madden, R. A., and P. R. Julian, 1972: Description of global-scale circulation cells in the tropics with a 40-50 day period. J. Atmos. Sci., 29, 1109-1123.
36. Mekonnen, A., C. D. Thorncroft, and A. R. Aiyyer, 2006: Analysis of convection and its association with African easterly waves. J. Climate, 19, 5405-5421.
37. Mounier, F., S. Janicot, and G. N. Kiladis, 2008: The West African monsoon dynamics. Part III: The quasi-biweekly zonal dipole. J. Climate, 21, 1911-1928.
38. Onogi, K., and Coauthors, 2007: The JRA-25 Reanalysis. J. Meteor. Soc. Japan, 85, 369-432.
39. Oppenheim, A. V., and R. W. Schafer, 1975: Digital Signal Processing. Prentice-Hall, 585 pp.
40. Parker, D. J., and Coauthors, 2008: The AMMA radiosonde program and its implications for the future of atmospheric monitoring over Africa. Bull. Amer. Meteor. Soc., 89, 1015-1027.
41. Reale, O., L. Feudale, and B. Turato, 2001: Evaporative moisture sources during a sequence of floods in the Mediterranean region. Geophys. Res. Lett., 28, 2085-2088.
42. Rienecker, M. M., and Coauthors, 2008: The GEOS-5 Data Assimilation System-Documentation of versions 5.0.1, 5.1.0 and 5.20. NASA Tech. Rep. Series on Global Modeling and Data Assimilation, NASA/TM-2008-104606, Vol. 27, 102 pp. [Available online at http://gmao.gsfc.nasa.gov/pubs/tm/.]
43. Shapiro, L. J., 1977: Tropical storm formation from easterly waves: A criterion for development. J. Atmos. Sci., 34, 1007-1021.
44. Shapiro, L. J., and S. B. Goldenberg, 1998: Atlantic sea surface temperatures and tropical cyclone formation. J. Climate, 11, 578-590.
45. Thorncroft, C. D., and B. J. Hoskins, 1994a: An idealized study of African easterly waves. Part I: A linear view. Quart. J. Roy. Meteor. Soc., 120, 953-982.
46. Thorncroft, C. D., and B. J. Hoskins, 1994b: An idealized study of African easterly waves. Part II: A non-linear view. Quart. J. Roy. Meteor. Soc., 120, 983-1015.
47. Thorncroft, C. D., and M. Blackburn, 1999: Maintenance of the African easterly jet. Quart. J. Roy. Meteor. Soc., 125, 763-786.
48. Thorncroft, C. D., J. Hall, and G. N. Kiladis, 2008: Three-dimensional structure and dynamics of African easterly waves. Part III: Genesis. J. Atmos. Sci., 65, 3596-3607.
49. Turato, B., O. Reale, and F. Siccardi, 2004: Water vapor sources of the October 2000 Piedmont flood. J. Hydrometeor., 5, 693-712.
50. Uppala, S. M., and Coauthors, 2005: The ERA-40 Re-Analysis. Quart. J. Roy. Meteor. Soc., 131, 2961-3012.
51. Vizy, E. K., and K. H. Cook, 2009: A mechanism for African monsoon breaks: Mediterranean cold air surges. J. Geophys. Res., 114, D01104, doi:10.1029/2008JD010654.
52. Wheeler, M. C., and H. H. Hendon, 2004: An all-season multivariate MJO index: Development of an index for monitoring and prediction. Mon. Wea. Rev., 132, 1917-1932.
53. Wu, M.-L. C., S. D. Schubert, and N. E. Huang, 1999: The development of the South Asian summer monsoon and the intraseasonal oscillation. J. Climate, 12, 2054-2075.
54. Wu, M.-L. C., O. Reale, S. D. Schubert, M. J. Suarez, R. D. Koster, P. J. Pegion, 2009a: African easterly jet: Structure and maintenance. J. Climate, 22, 4459-4480.
55. Wu, M.-L. C., S. D. Schubert, and N. E. Huang, 2009b: An analysis of moisture fluxes into the Gulf of California. J. Climate, 22, 2216-2239.
56. Yanai, M., and M. Murakami, 1970: Spectrum analysis of symmetric and anti-symmetric equatorial waves. J. Meteor. Soc. Japan, 48, 331-346.