Abstract
In this study, we aimed to elucidate the critical role of moisture transport affecting monsoon activity in two contrasting summers over the Arabian Sea during the years 1994, a relatively wet year, and 2002, a relatively dry year. A comprehensive diagnostic evaluation and comparisons of the moisture fields were conducted; we focused on the precipitation and evaporation as well as the moisture transport and its divergence or convergence in the atmosphere. Monthly mean reanalysis data were obtained from the National Centers for Environmental Prediction (NCEP-I and -II). A detailed evaluation of the moisture budgets over Pakistan during these two years was made by calculating the latent energy flux at the surface (E-P) from the divergence of the total moisture transport. Our results confirm the moisture supply over the Arabian Sea to be the major source of rainfall in Pakistan and neighboring regions. In 1994, Pakistan received more rainfall compared to 2002 during the summer monsoon. Moisture flow deepens and strengthens over Arabian Sea during the peak summer monsoon months of July and August. Our analysis shows that vertically integrated moisture transport flux have a significant role in supplying moisture to the convective centers over Pakistan and neighboring regions from the divergent regions of the Arabian Sea and the Bay of Bengal. Moreover, in 1994, a deeper vertically integrated moisture convergence progression occurred over Pakistan compared to that in 2002. Perhaps that deeper convergence resulted in a more intense moisture depression over Pakistan and also caused more rainfall in 1994 during the summer monsoon. Finally, from the water budget analysis, it has been surmised that the water budget was larger in 1994 than in 2002 during the summer monsoon.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Cadet, D. L., and G. Reverdin, 1981: Water vapor transport over the Indian Ocean during summer 1975. Tellus, 33, 476–487.
Fasullo, J., and P. J. Webster, 2003: A hydrological definition of the Indian summer monsoon onset and withdrawal. J. Climate, 16, 3200–3211.
Flohn, H., D. Henning, and H. C. Korff, 1965: Studies on the water vapor transport over northern Africa. Bonner Met. Abhandlungen, Heft 6. Meteorologisches Institut der Universität Bonn, 36pp.
Houze, R. A. Jr., D. C. Wilton, and B. F. Smull, 2007: Monsoon convection in the Himalayan region as seen by the TRMM Precipitation Radar. Quart. J. Roy. Meteor. Soc., 133, 1389–1411.
Huffman, G. J., and Coauthors, 1997: The Global Precipitation Climatology Project (GPCP) combined precipitation dataset. Bull. Amer. Meteor. Soc., 78, 5–20.
Izumo, T., C. De Boyer Montegut, J. J. Luo, S. K. Behera, S. Masson, and T. Yamagata, 2008: The role of the western Arabian Sea upwelling in Indian monsoon rainfall variability. J. Climate, 21, 5603–5623.
Kalnay, E., and Coauthors, 1996: The NCEP/NCAR Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437–471.
Kistler, R., and Coauthors, 2001: The NCEP-NCAR 50-Year Reanalysis: Monthly means CD-ROM and documentation. Bull. Amer. Meteor. Soc., 82, 247–268.
Krishnan, R., V. Kumar, M. Sugi, and J. Yoshimura, 2009: Internal feedbacks from monsoon-midlatitude interactions during droughts in the Indian summer monsoon. J. Atmos. Sci., 66, 553–578.
Medina, S., R. A. Houze Jr., A. Kumar, and D. Niyogi, 2010: Summer monsoon convection in the Himalayan region: Terrain and land cover effects. Quart. J. Roy. Meteor. Soc., 136, 593–616.
Mo, K. C., and R. W. Higgins, 1996: Large scale atmospheric moisture transport as evaluated in the NCEP/NCAR and the NASA/DAO reanalyses. J. Climate, 9, 1531–1545.
Murakami, T., T. Nakazawa, and T. He, 1984: On the 40–50 day oscillation during the 1979 Northern Hemisphere Summer. Part II: Heat and moisture budget. J. Meteor. Soc. Japan, 62, 469–484.
Newell, R. E., J. W. Kidson, D. G. Vincent, and G. J. Boer, Eds., 1972a: The General Circulation of the Tropical Atmosphere. Vol.1, the MIT Press, 258pp.
Ninomiya, K., and C. Kobayashi, 1999: Precipitation and moisture balance of the Asian summer monsoon in 1991, Part II: Moisture transport and moisture balance. J. Meteor. Soc. Japan, 77, 77–99.
Pisharoty, P. R., 1965: Evaporation over the Arabian Sea and the Indian Southwest Monsoon. Proc. Int. Indian Ocean Expedition, P. R. Pisharoty, Ed., 43–54.
Pant, G. B., and K. R. Kumar, 1997: Climates of South Asia. John Wiley and Sons, Chichester, UK, 320pp.
Rakhecha, P. R., and P. R. Pisharoty, 1996: Heavy rainfall during monsoon season: Point and spatial distribution. Current Science, 71, 179–186.
Rasmusson, E. M., 1972: Seasonal variation of the tropical humidity parameters. The General Circulation of the Tropical Atmosphere, Vol. 1, Newell et al., Eds., the MIT Press, 193–221.
Saha, K. R., 1974: Some aspects of the Arabian Sea summer monsoon. Tellus, 26, 464–476.
Saha, K. R., and S. N. Bavadekar, 1973: Water vapour budget and precipitation over the Arabian Sea during the northern summer. Quart. J. Roy. Meteor. Soc., 99, 273–278.
Saha, K. R., and S. N. Bavadekar, 1977: Moisture flux across the west coast of India and rainfall during the southwest monsoon. Quart. J. Roy. Meteor. Soc., 103, 370–374.
Shukla, J. and B. N. Misra, 1977: Relationships between sea surface temperature and wind speed over the Central Arabia Sea and monsoon rainfall over India. Mon. Wea. Rev., 105, 998–1002.
Trenberth, K. E., 1991: Climate diagnostics from global analyses: Conservation of mass in ECMWF analyses. J. Climate, 4, 707–722.
Trenberth, K. E., and C. J. Guillemot, 1995: Evaluation of the atmospheric moisture budget as seen from analyses. J. Climate, 8, 2255–2272.
Trenberth, K. E., and C. J. Guillemot, 1996: Evaluation of the atmospheric moisture and hydrological cycle in the NCEP reanalyses. NCAR Tech. Note NCAR/TN-4301STR, 300pp.
Trenberth, K. E., and C. J. Guillemot, 1998: Evaluation of the atmospheric moisture and hydrological cycle in the NCEP/NCAR reanalyses. Climate Dyn., 14, 213–231.
Webster, P. J., 1994: The role of hydrological processes in ocean-atmosphere interaction. Rev. Geophys. 32, 427–476.
Webster, P. J., V. O. Magana, T. N. Palmer, J. Shukla, R. A. Tomas, M. Yanai, and T. Yasunari, 1998: Monsoons: Processes, predictability, and the prospects for prediction. J. Geophys. Res., 103, 14451–14510.
Zheng, X., and E. Eltahir, 1998: The role of vegetation in the dynamics of West African monsoons. J. Climate, 11, 2078–2096.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ullah, K., Gao, S. Moisture transport over the Arabian Sea associated with summer rainfall over Pakistan in 1994 and 2002. Adv. Atmos. Sci. 29, 501–508 (2012). https://doi.org/10.1007/s00376-011-0200-y
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00376-011-0200-y