Abstract
Convective activity is one of the major processes in the atmosphere influencing the local and large-scale weather in the tropics. The latent heat released by the cumulus cloud is known to drive monsoon circulation, which on the other hand supplies the moisture that maintains the cumulus clouds. An investigation is carried out on the convective structure of the atmosphere during active and suppressed periods of convection using data sets obtained from the Bay of Bengal and Monsoon Experiment (BOBMEX). The cumulus convection though being a small-scale phenomenon, still influences its embedding environment by interaction through various scales. This study shows the variation in the kinematic and convective parameters during the transition from suppressed to active periods of convection. Convergence in the lower levels and strong upward vertical velocity, significant during active convection are associated with the formation of monsoon depressions. The apparent heat source due to latent heat release and the vertical transport of the eddy heat by cumulus convection, and the apparent moisture sink due to net condensation and vertical divergence of the eddy transport of moisture, are estimated through residuals of the thermodynamic equation and examined in relation to monsoon activity during BOBMEX.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Betts A K 1976 Modeling subcloud layer structure and interaction with a shallow cumulus layer;J. Atmos. Sci. 33 2363–2382
Bhat G S, Gadgil S, Hareesh Kumar P V, Kalsi S R, Madhusoodan P, Murty V S N, Prasada Rao C V K, Ramesh Babu V, Rao L V G, Rao R R, Ravichandran M, Reddy K G, Sanjeeva Rao P, Sengupta D, Sikka D R, Swain J and Vinaychandran P N 2001 BOBMEX: The Bay of Bengal Monsoon Experiment;Bull. Amer. Meteor. Soc. 82 2217–2243
Bhat G S, Chakraborty A, Nanjundiah R S and Srinivasan J 2002 Vertical thermal structure of the atmosphere during active and weak phases of convection over the north Bay of Bengal: Observation and model results;Curr. Sci. 83 296–302
Chang C -P 1970 Westward propagating cloud patterns in the tropical Pacific as seen from time composite satellite photographs;J. Atmos. Sci. 27 133–138
Charney J G and Eliassen A 1964 On the growth of the hurricane depression;J. Atmos. Sci. 21 68–75
DST 1996 Indian Climate Research Programme science plan. Department of Science and Technology, New Delhi, India, 186 pp.
Ebert E E and Holland G J 1992Mon. Weather Rev. 120 2240–2251
Emmanuel K A 1994Atmospheric Convection, (Oxford: Oxford University Press), pp 580
Houze R A Jr 1993Cloud Dynamics, (New York: Academic Press) pp 572
Mohanty U C and Das S 1986 On the structure of the atmosphere during suppressed and active periods of convection over the Bay of Bengal;Proc. Indian Acad. Sci. (Earth Planet. Sci.) 52 625–640
Krishnamurti T N, Ramanathan Y, Ardanuy P and Pasch R 1979 Quick Look “Summer MONEX Atlas” Part II, the onset phase; Rep. No. 79-5, Dept. of Meteorology, Florida State University, Tallahassee, Florida.
Nitta T 1972 Energy budget of wave disturbances over the Marshall Islands during the years of 1956 and 1958;Meteorol. Soc. Jpn. 50 71–84
Nitta T 1975 Observational determination of cloud mass flux distributions;J. Atmos. Sci. 32 73–91
O' Brien J J 1970 Alternate solutions to the classical vertical velocity problem;J. Appl. Met. 9 197–203
Ogura Y and Cho H R 1973 Diagnostic determination of cumulus cloud populations from observed large-scale variables;J. Atmos. Sci. 30 1276–1286
Omotosho J A 1982Ph D Thesis, University of Reading.
Ooyama K 1964 A dynamical model for the study of tropical cyclone development;Geofis. Intern. 4 187–198
Ooyama K 1969a Numerical simulation of the life cycle of tropical cyclones;J. Atmos. Sci. 26 3–40
Rao Y P 1976 Southwest monsoon. Synoptic meteorology;Meteorological Monogr. IMD 1 367 pp.
Riehl H and Malkus J S 1958 On the heat balance in the equatorial trough zone;Geophysica 6 530–538
Riehl H and Malkus J S 1961 Some aspects of hurricane Daisy, 1958,Tellus 13 181–213
Sam N V, Mohanty U C and Satyanarayana A N V 2003 Simulation of Marine Boundary Layer characteristics using a 1-D PBL model over the Bay of Bengal during BOBMEX-99;Proc. Indian Acad. Sci. (Earth Planet. Sci.) 1122 185–204
Sikka D R and Grossman B 1980 Summer MONEX chronological weather summary, International MONEX Management Centre, New Delhi.
Thapliyal V, Desai D S and Krishnan V 2000 Weather in India, monsoon season (June–September 1999);Mausam 51 285–318
Thompson R M Jr, Payne S W, Recker E E and Reed R J 1979 Structures and properties of synoptic-scale wave disturbances in the inter-tropical convergence zone of the eastern Atlantic;J. Atmos. Sci. 36 53–72
Yanai M 1961a A detailed analysis of typhoon formation,J. Meteorol. Soc. Jpn. 39 187–214
Yanai M 1961b Dynamical aspects of typhoon formation;J. Meteorol. Soc. Jpn. 39 283–309
Yanai M, Esbensen S and Chu J 1973 Determination of bulk properties of tropical cloud clusters from large-scale heat and moisture budgets;J. Atmos. Sci. 30 611–627
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mohanty, U.C., Sam, N.V., Das, S. et al. A study on the structure of the convective atmosphere over the Bay of Bengal during BOBMEX-99. J Earth Syst Sci 112, 147–163 (2003). https://doi.org/10.1007/BF02701984
Issue Date:
DOI: https://doi.org/10.1007/BF02701984