• Adler, R., G. J. Huffman, D. Bolvin, S. Curtis, and E. Nelkin, 2000: Tropical rainfall distributions determined using TRMM combined with other satellite and rain gauge information. J. Appl. Meteor., 39 , 20072023.

    • Search Google Scholar
    • Export Citation
  • Arkin, P., 1979: The relationship between fractional coverage of high cloud and rainfall accumulations during GATE over the B-scale array. Mon. Wea. Rev., 107 , 13821387.

    • Search Google Scholar
    • Export Citation
  • Arkin, P., A. K. Rao, and R. R. Kelkar, 1989: Large-scale precipitation and outgoing longwave radiation from INSAT-1B during the 1986 southwest monsoon season. J. Climate, 2 , 619628.

    • Search Google Scholar
    • Export Citation
  • Baker, R., B. Lynn, A. Boone, W-K. Tao, and J. Simpson, 2001: The influence of soil moisture, coastline curvature, and land-breeze circulations on sea-breeze-initiated precipitation. J. Hydrometeor., 2 , 193211.

    • Search Google Scholar
    • Export Citation
  • Bhat, G., and Coauthors. 2001: BOBMEX: The Bay of Bengal Monsoon Experiment. Bull. Amer. Meteor. Soc., 82 , 22172243.

  • Chen, S. S., and R. A. Houze, 1997: Diurnal variation and life-cycle of deep convective systems over the tropical Pacific warm pool. Quart. J. Roy. Meteor. Soc., 123 , 357388.

    • Search Google Scholar
    • Export Citation
  • Chen, S. S., R. A. Houze, and B. E. Mapes, 1996: Multiscale variability of deep convection in relation to large-scale circulation in TOGA COARE. J. Atmos. Sci., 53 , 13801409.

    • Search Google Scholar
    • Export Citation
  • Gray, W., and R. Jacobsen, 1977: Diurnal variation of deep cumulus convection. Mon. Wea. Rev., 105 , 11711188.

  • Grossman, R., and D. Durran, 1984: Interaction of low-level flow with the western Ghat mountains and offshore convection in the summer monsoon. Mon. Wea. Rev., 112 , 652672.

    • Search Google Scholar
    • Export Citation
  • Grossman, R., and O. Garcia, 1990: The distribution of deep convection over ocean and land during the Asian summer monsoon. J. Climate, 3 , 10321044.

    • Search Google Scholar
    • Export Citation
  • Houze, R. A., S. G. Geotis, J. Marks, and A. West, 1981: Winter monsoon convection in the vicinity of north Borneo. Part I: Structure and time variation of clouds and precipitation. Mon. Wea. Rev., 109 , 15951614.

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

  • Laing, A., and J. Fritsch, 1993: Mesoscale convective complexes over the Indian monsoon region. J. Climate, 6 , 911919.

  • Lau, K-H., and N-C. Lau, 1990: Observed structure and propagation characteristics of tropical summertime synoptic-scale disturbances. Mon. Wea. Rev., 118 , 18881913.

    • Search Google Scholar
    • Export Citation
  • Lau, K-H., and N-C. Lau, 1992: The energetics and propagation dynamics of tropical summertime synoptic-scale disturbances. Mon. Wea. Rev., 120 , 25232539.

    • Search Google Scholar
    • Export Citation
  • Lawrence, D. M., and P. Webster, 2001: Interannual variations of the intraseasonal oscillation in the south Asian summer monsoon region. J. Climate, 14 , 29102922.

    • Search Google Scholar
    • Export Citation
  • Liebmann, B., H. Hendon, and J. Glick, 1994: The relationship between tropical cyclones of the western Pacific and Indian Oceans and the Madden–Julian oscillation. J. Meteor. Soc. Japan, 72 , 401411.

    • Search Google Scholar
    • Export Citation
  • Ludlam, F., 1980: Clouds and Storms. Pennsylvania State University Press, 405 pp.

  • Machado, L., W. Rossow, R. Guedes, and A. Walker, 1998: Life cycle variations of mesoscale convective systems over the Americas. Mon. Wea. Rev., 126 , 16301654.

    • Search Google Scholar
    • Export Citation
  • Mapes, B., and R. Houze, 1993: Cloud clusters and superclusters over the oceanic warm pool. Mon. Wea. Rev., 121 , 13981415.

  • Mapes, B., T. T. Warner, and M. Xu, 2003: 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
  • Mathon, V., and H. Laurent, 2001: Life cycle of Sahelian mesoscale convective cloud systems. Quart. J. Roy. Meteor. Soc., 127 , 377406.

    • Search Google Scholar
    • Export Citation
  • Nesbitt, S., and E. Zipser, 2000: A census of precipitation features in the Tropics using TRMM: Radar, ice scattering, and lightning observations. J. Climate, 13 , 40874106.

    • Search Google Scholar
    • Export Citation
  • Neumann, J., 1951: Land breezes and nocturnal thunderstorms. J. Meteor., 8 , 6067.

  • Newell, R. E., and S. Gould-Stewart, 1981: A stratospheric fountain. J. Atmos. Sci., 38 , 27892796.

  • Ohsawa, T., H. Ueda, T. Hayashi, A. Watanabe, and J. Matsumoto, 2001: Diurnal variations of convective activity and rainfall in tropical Asia. J. Meteor. Soc. Japan, 79 , 333352.

    • Search Google Scholar
    • Export Citation
  • Redelsperger, J-L., and J-P. Lafore, 1988: A three-dimensional simulation of a tropical squall line: Convective organization and thermodynamic vertical transport. J. Atmos. Sci., 45 , 13341356.

    • Search Google Scholar
    • Export Citation
  • Redelsperger, J-L., D. Parsons, and F. Guichard, 2002: Recovery processes and factors limiting cloud-top height following the arrival of a dry intrusion observed during TOGA COARE. J. Atmos. Sci., 59 , 24382457.

    • Search Google Scholar
    • Export Citation
  • Rickenbach, T. M., 1999: Cloud-top evolution of tropical oceanic squall lines from radar reflectivity and infrared satellite data. Mon. Wea. Rev., 127 , 29512976.

    • Search Google Scholar
    • Export Citation
  • Rickenbach, T. M., and S. A. Rutledge, 1998: Convection in TOGA COARE: Horizontal scale, morphology, and rainfall production. J. Atmos. Sci., 55 , 27152729.

    • Search Google Scholar
    • Export Citation
  • Roca, R., and V. Ramanathan, 2000: Scale dependence of monsoonal convective systems over the Indian Ocean. J. Climate, 13 , 12861298.

  • Sheu, R-S., J. A. Curry, and G. Liu, 1997: Vertical stratification of tropical cloud properties as determined from satellite. J. Geophys. Res., 102 (D4) 42314245.

    • Search Google Scholar
    • Export Citation
  • Short, D. A., and K. Nakamura, 2000: TRMM radar observations of shallow precipitation over the tropical oceans. J. Climate, 13 , 41074124.

    • Search Google Scholar
    • Export Citation
  • Smith, E. A., and A. Mehta, 1990: The role of organized tropical storms and cyclones on intraseasonal oscillations in the Asian monsoon domain based on INSAT satellite measurements. Meteor. Atmos. Phys., 44 , 195218.

    • Search Google Scholar
    • Export Citation
  • Spencer, K., and T. Palmer, 1996: Interannual tropical rainfall variability in general circulation model simulations associated with the Atmospheric Model Intercomparison Project. J. Climate, 9 , 27272750.

    • Search Google Scholar
    • Export Citation
  • Spencer, R., 1993: Global oceanic precipitation from the MSU during 1979–91 and comparison to other climatologies. J. Climate, 6 , 13011326.

    • Search Google Scholar
    • Export Citation
  • Toracinta, E., and E. Zipser, 2001: Lightning and SSM/I ice-scattering mesoscale convective systems in the global Tropics. J. Appl. Meteor., 40 , 9831002.

    • Search Google Scholar
    • Export Citation
  • Webster, P., and Coauthors. 2002: The JASMINE pilot study. Bull. Amer. Meteor. Soc., 83 , 16031630.

  • Williams, M., and R. A. Houze, 1987: Satellite-observed characteristics of winter monsoon clouds clusters. Mon. Wea. Rev., 115 , 505519.

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

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 374 197 25
PDF Downloads 278 154 20

Convective Clouds over the Bay of Bengal

View More View Less
  • 1 NOAA/Environmental Technology Laboratory, Boulder, Colorado
Restricted access

Abstract

The behavior of convective activity over the Bay of Bengal during the 1988 and 1999 monsoon seasons is examined using 3-hourly satellite infrared data. More organized convective activity, spreading farther south into the bay, occurred in 1988 than in 1999. A distinct spatial grouping of convective systems by size is found. The east side of the bay experiences most of the rainfall over water, and here the convective systems are relatively small, short lived, and frequent. At the northwest side of the bay near most of the land-based rainfall, convective activity is organized into much larger and longer-lived systems. The diurnal cycle of all the systems over the bay, regardless of size, shows a 0600 local time (LT) maximum in very cold cloud tops (infrared brightness temperature <210 K), with genesis occurring between 2100 and 0300 LT (2100 LT for the larger, longer-lived systems). The cloud systems dissipate after sunrise, with the larger systems lasting until the afternoon. The land–water interface is important for the convection genesis and thereby affects the spatial distribution of convection. Offshore nocturnal convection begins near shore, with later convection occurring farther out over the bay and attaining a larger size. The preference for nocturnal initiation times differs markedly from the afternoon initiation times typical of the tropical western Pacific Ocean, but the time of maximum cloud area extent and dissipation are similar. The strength of the diurnal cycle varies greatly with location, with the northwest side of the bay experiencing both the highest amount of very cold cloudiness and the strongest diurnal cycle. The Joint Air–Sea Monsoon Interaction Experiment (JASMINE) research cruise experienced the only multiday sequence of large, diurnally repeating, southward moving disturbances at 11°N, 89°E in the 2 yr examined, but both the convective diurnal cycle and propagation direction were consistent with climatology. An interesting aspect of the convective life cycle is that systems often have a southward component to their motion, with the most common propagation direction over the entire bay being to the southwest. This can occur even when the larger-scale movement is toward the northwest (such as is typical for cyclones at the northern end of the bay).

Corresponding author address: P. Zuidema, NOAA/ETL/ET6, 325 Broadway, Boulder, CO 80305-3337. Email: paquita.zuidema@noaa.gov

Abstract

The behavior of convective activity over the Bay of Bengal during the 1988 and 1999 monsoon seasons is examined using 3-hourly satellite infrared data. More organized convective activity, spreading farther south into the bay, occurred in 1988 than in 1999. A distinct spatial grouping of convective systems by size is found. The east side of the bay experiences most of the rainfall over water, and here the convective systems are relatively small, short lived, and frequent. At the northwest side of the bay near most of the land-based rainfall, convective activity is organized into much larger and longer-lived systems. The diurnal cycle of all the systems over the bay, regardless of size, shows a 0600 local time (LT) maximum in very cold cloud tops (infrared brightness temperature <210 K), with genesis occurring between 2100 and 0300 LT (2100 LT for the larger, longer-lived systems). The cloud systems dissipate after sunrise, with the larger systems lasting until the afternoon. The land–water interface is important for the convection genesis and thereby affects the spatial distribution of convection. Offshore nocturnal convection begins near shore, with later convection occurring farther out over the bay and attaining a larger size. The preference for nocturnal initiation times differs markedly from the afternoon initiation times typical of the tropical western Pacific Ocean, but the time of maximum cloud area extent and dissipation are similar. The strength of the diurnal cycle varies greatly with location, with the northwest side of the bay experiencing both the highest amount of very cold cloudiness and the strongest diurnal cycle. The Joint Air–Sea Monsoon Interaction Experiment (JASMINE) research cruise experienced the only multiday sequence of large, diurnally repeating, southward moving disturbances at 11°N, 89°E in the 2 yr examined, but both the convective diurnal cycle and propagation direction were consistent with climatology. An interesting aspect of the convective life cycle is that systems often have a southward component to their motion, with the most common propagation direction over the entire bay being to the southwest. This can occur even when the larger-scale movement is toward the northwest (such as is typical for cyclones at the northern end of the bay).

Corresponding author address: P. Zuidema, NOAA/ETL/ET6, 325 Broadway, Boulder, CO 80305-3337. Email: paquita.zuidema@noaa.gov

Save