• Garreaud, R. D., and J. M. Wallace, 1997: The diurnal march of convective cloudiness over the Americas. Mon. Wea. Rev., 125 , 31573171.

    • Search Google Scholar
    • Export Citation
  • Gu, G., and C. Zhang, 2001: A spectrum analysis of synoptic-scale disturbances in the ITCZ. J. Climate, 14 , 27252739.

  • Hastenrath, S., 1990: Diagnostics and prediction of anomalous river discharge in northern South America. J. Climate, 3 , 10801096.

  • Hastenrath, S., 2002: The intertropical convergence zone of the eastern Pacific revisited. Int. J. Climatol., 22 , 347356.

  • Hendon, H., and K. Woodberry, 1993: The diurnal cycle of tropical convection. J. Geophys. Res., 98 , 1662316637.

  • Imaoka, K., and R. W. Spencer, 2000: Diurnal variation of precipitation over the tropical oceans observed by TRMM/TMI combined with SSM/I. J. Climate, 13 , 41494158.

    • Search Google Scholar
    • Export Citation
  • Janowiak, J. E., P. A. Arkin, and M. Morrissey, 1994: An examination of the diurnal cycle in oceanic tropical rainfall using satellite and in situ data. Mon. Wea. Rev., 122 , 22962311.

    • Search Google Scholar
    • Export Citation
  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • Kousky, V., 1980: Diurnal rainfall variations in northeast Brazil. Mon. Wea. Rev., 108 , 488498.

  • León, G. E., J. A. Zea, and J. A. Eslava, 2000: General circulation and the intertropical convergence zone in Colombia (in Spanish). Meteor. Colomb., 1 , 3138.

    • Search Google Scholar
    • Export Citation
  • Lin, X., D. A. Randall, and L. D. Fowler, 2000: Diurnal variability of the hydrologic cycle and radiative fluxes: Comparisons between observations and a GCM. J. Climate, 13 , 41594179.

    • Search Google Scholar
    • Export Citation
  • López, M. E., and W. E. Howell, 1967: Katabatic winds in the equatorial Andes. J. Atmos. Sci., 24 , 2935.

  • Machado, L. A. T., H. Laurent, and A. A. Lima, 2002: Diurnal march of the convection observed during TRMM-WETAMC/LBA. J. Geophys. Res., 107 , 8064. doi: 10.1029/2001JD000338.

    • Search Google Scholar
    • Export Citation
  • Madden, R. A., and P. A. Julian, 1994: Observations of the 40–50-day tropical oscillation—A review. Mon. Wea. Rev., 122 , 814837.

  • Maloney, E. D., and D. L. Hartmann, 2000: Modulation of hurricane activity in the Gulf of Mexico by the Madden–Julian oscillation. Science, 287 , 20022003.

    • Search Google Scholar
    • Export Citation
  • Mapes, B. E., T. T. Warner, M. Xu, and A. J. Negri, 2003a: Diurnal patterns of rainfall in northwestern South America. Part I: Observations and context. Mon. Wea. Rev., 131 , 799812.

    • Search Google Scholar
    • Export Citation
  • Mapes, B. E., T. T. Warner, and M. Xu, 2003b: Diurnal patterns of rainfall in northwestern South America. Part III: Diurnal gravity waves and nocturnal convection offshore. Mon. Wea. Rev., 131 , 830844.

    • Search Google Scholar
    • Export Citation
  • Martínez, M. T., 1993: Influence on weather patterns of major synoptic scale systems in Colombia (in Spanish). Atmósfera, 16 , 110.

  • Meisner, B. N., and P. A. Arkin, 1987: Spatial and annual variations in the diurnal cycle of large-scale tropical convective clouds and precipitation. Mon. Wea. Rev., 115 , 20092032.

    • Search Google Scholar
    • Export Citation
  • Mejía, J. F., and Coauthors, 1999: Spatial distribution, annual and semi-annual cycles of precipitation in Colombia (in Spanish). DYNA, 127 , 726.

    • Search Google Scholar
    • Export Citation
  • Myers, N., R. A. Mittermeier, C. G. Mittermeier, G. A. B. da Fonseca, and J. Kent, 2000: Biodiversity hotspots for conservation priorities. Nature, 403 , 853858.

    • Search Google Scholar
    • Export Citation
  • Negri, A. J., R. F. Adler, E. J. Nelkin, and G. J. Huffman, 1994: Regional rainfall climatologies derived from Special Sensor Microwave Imager (SSM/I) data. Bull. Amer. Meteor. Soc., 75 , 11651182.

    • Search Google Scholar
    • Export Citation
  • Negri, A. J., E. N. Anagnostou, and R. F. Adler, 2000: A 10-year climatology of Amazonian rainfall derived from passive microwave satellite observations. J. Appl. Meteor., 39 , 4256.

    • Search Google Scholar
    • Export Citation
  • Negri, A. J., T. L. Bell, and L. Xu, 2002a: Sampling of the diurnal cycle of precipitation using TRMM. J. Atmos. Oceanic Technol., 19 , 13331344.

    • Search Google Scholar
    • Export Citation
  • Negri, A. J., L. Xu, and R. F. Adler, 2002b: A TRMM-calibrated infrared rainfall algorithm, applied over Brazil. J. Geophys. Res., 107 , 8048. doi: 10.1029/2000JD000265.

    • Search Google Scholar
    • Export Citation
  • Poveda, G., 1994: Empirical orthogonal functions in the relationship between river streamflows and sea surface temperatures in the Pacific and Atlantic Oceans. Proc. XVI Latin American Hydraulics and Hydrology Meeting (in Spanish), Santiago, Chile, IAHR, 131–144.

  • Poveda, G., and O. J. Mesa, 1997: Feedbacks between hydrological processes in tropical South America and large-scale oceanic–atmospheric phenomena. J. Climate, 10 , 26902702.

    • Search Google Scholar
    • Export Citation
  • Poveda, G., and A. Jaramillo, 2000: ENSO-related variability of river discharges and soil moisture in Colombia. Biospheric Aspects of the Hydrologic Cycle, No. 8, IGBP, 3–6.

    • Search Google Scholar
    • Export Citation
  • Poveda, G., and O. J. Mesa, 2000: On the existence of Lloró (the rainiest locality on earth): Enhanced ocean–atmosphere–land interaction by a low-level jet. Geophys. Res. Lett., 27 , 16751678.

    • Search Google Scholar
    • Export Citation
  • Poveda, G., A. Jaramillo, M. M. Gil, N. Quiceno, and R. I. Mantilla, 2001: Seasonality in ENSO related precipitation, river discharges, soil moisture, and vegetation index (NDVI) in Colombia. Water Resour. Res., 37 , 21692178.

    • Search Google Scholar
    • Export Citation
  • Press, W. H., B. P. Flannery, P. Brian, S. Teukolsky, and W. T. Vetterling, 1986: Numerical Recipes: The Art of Scientific Computing. Cambridge University Press, 818 pp.

    • Search Google Scholar
    • Export Citation
  • Ricciardulli, L., and P. D. Sardeshmukh, 2002: Local time- and space scales of organized tropical deep convection. J. Climate, 15 , 27752790.

    • Search Google Scholar
    • Export Citation
  • Snow, J. W., 1976: The climate of northern South America. Climates of Central and South America, W. Schwerdtfeger, Ed., Elsevier, 295–403.

    • Search Google Scholar
    • Export Citation
  • Soden, B., 2000: The diurnal cycle of convection, clouds and water vapor in the tropical upper troposphere. Geophys. Res. Lett., 27 , 21732176.

    • Search Google Scholar
    • Export Citation
  • Sorooshian, S., X. Gao, K. Hsu, R. A. Maddox, Y. Hong, H. V. Gupta, and B. Imam, 2002: Diurnal variability of tropical rainfall retrieved from combined GOES and TRMM satellite information. J. Climate, 15 , 9831001.

    • Search Google Scholar
    • Export Citation
  • Torrence, C., and G. P. Compo, 1998: A practical guide to wavelet analysis. Bull. Amer. Meteor. Soc., 79 , 6178.

  • Trojer, H., 1959: Fundamentos para una zonificación meteorológica y climatológica del trópico y especialmente de Colombia. Rev. Cenicafé, 10 , 288373.

    • Search Google Scholar
    • Export Citation
  • Velasco, I., and M. Frisch, 1987: Mesoscale convective complexes in the Americas. J. Geophys. Res., 92 , D8,. 95919613.

  • Warner, T. T., B. E. Mapes, and M. Xu, 2003: Diurnal patterns of rainfall in northwestern South America. Part II: Model simulations. Mon. Wea. Rev., 131 , 813829.

    • Search Google Scholar
    • Export Citation
  • Waylen, P. R., and G. Poveda, 2002: El Niño–Southern Oscillation and aspects of western South America hydro-climatology. Hydrol. Processes, 16 , 12471260.

    • Search Google Scholar
    • Export Citation
  • Yang, G. Y., and J. Slingo, 2001: The diurnal cycle in the Tropics. Mon. Wea. Rev., 129 , 784801.

  • Zulauga, M. D., and G. Poveda, 2004: Diagnostics of mesoscale convective systems in Colombia and the eastern Pacific during 1998–2002 using TRMM data (in Spanish). Av. Recur. Hidrául., in press.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 26 26 26
PDF Downloads 20 20 20

The Diurnal Cycle of Precipitation in the Tropical Andes of Colombia

View More View Less
  • 1 Escuela de Geociencias y Medio Ambiente, Universidad Nacional de Colombia, Medellín, Colombia
Restricted access

Abstract

Using hourly records from 51 rain gauges, spanning between 22 and 28 yr, the authors study the diurnal cycle of precipitation over the tropical Andes of Colombia. Analyses are developed for the seasonal march of the diurnal cycle and its interannual variability during the two phases of El Niño–Southern Oscillation (ENSO). Also, the diurnal cycle is analyzed at intra-annual time scales, associated with the westerly and easterly phases of the Madden–Julian oscillation, as well as higher-frequency variability (<10 days), mainly associated with tropical easterly wave activity during ENSO contrasting years. Five major general patterns are identified: (i) precipitation exhibits clear-cut diurnal (24 h) and semidiurnal (12 h) cycles; (ii) the minimum of daily precipitation is found during the morning hours (0900–1100 LST) regardless of season or location; (iii) a predominant afternoon peak is found over northeastern and western Colombia; (iv) over the western flank of the central Andes, precipitation maxima occur either near midnight, or during the afternoon, or both; and (v) a maximum of precipitation prevails near midnight amongst stations located on the eastern flank of the central Cordillera. The timing of diurnal maxima is highly variable in space for a fixed time, although a few coherent regions are found in small groups of rain gauges within the Cauca and Magdalena River valleys. Overall, the identified strong seasonal variability in the timing of rainfall maxima appears to exhibit no relationship with elevation on the Andes. The effects of both phases of ENSO are highly consistent spatially, as the amplitude of hourly and daily precipitation diminishes (increases) during El Niño (La Niña), but the phase remains unaltered for the entire dataset. We also found a generalized increase (decrease) in hourly and daily rainfall rates during the westerly (easterly) phase of the Madden–Julian oscillation, and a diminished (increased) high-frequency activity in July–October and February–April during El Niño (La Niña) years, associated, among others, with lower (higher) tropical easterly wave (4–6 day) activity over the Caribbean.

Corresponding author address: Germán Poveda, Escuela de Geociencias y Medio Ambiente, Facultad de Minas, Universidad Nacional de Colombia, Cra 80 x Calle 65, M2-315 Medellín, Colombia. Email: gpoveda@unalmed.edu.co

Abstract

Using hourly records from 51 rain gauges, spanning between 22 and 28 yr, the authors study the diurnal cycle of precipitation over the tropical Andes of Colombia. Analyses are developed for the seasonal march of the diurnal cycle and its interannual variability during the two phases of El Niño–Southern Oscillation (ENSO). Also, the diurnal cycle is analyzed at intra-annual time scales, associated with the westerly and easterly phases of the Madden–Julian oscillation, as well as higher-frequency variability (<10 days), mainly associated with tropical easterly wave activity during ENSO contrasting years. Five major general patterns are identified: (i) precipitation exhibits clear-cut diurnal (24 h) and semidiurnal (12 h) cycles; (ii) the minimum of daily precipitation is found during the morning hours (0900–1100 LST) regardless of season or location; (iii) a predominant afternoon peak is found over northeastern and western Colombia; (iv) over the western flank of the central Andes, precipitation maxima occur either near midnight, or during the afternoon, or both; and (v) a maximum of precipitation prevails near midnight amongst stations located on the eastern flank of the central Cordillera. The timing of diurnal maxima is highly variable in space for a fixed time, although a few coherent regions are found in small groups of rain gauges within the Cauca and Magdalena River valleys. Overall, the identified strong seasonal variability in the timing of rainfall maxima appears to exhibit no relationship with elevation on the Andes. The effects of both phases of ENSO are highly consistent spatially, as the amplitude of hourly and daily precipitation diminishes (increases) during El Niño (La Niña), but the phase remains unaltered for the entire dataset. We also found a generalized increase (decrease) in hourly and daily rainfall rates during the westerly (easterly) phase of the Madden–Julian oscillation, and a diminished (increased) high-frequency activity in July–October and February–April during El Niño (La Niña) years, associated, among others, with lower (higher) tropical easterly wave (4–6 day) activity over the Caribbean.

Corresponding author address: Germán Poveda, Escuela de Geociencias y Medio Ambiente, Facultad de Minas, Universidad Nacional de Colombia, Cra 80 x Calle 65, M2-315 Medellín, Colombia. Email: gpoveda@unalmed.edu.co

Save