• Annamalai, H., , J. M. Slingo, , K. R. Sperber, , and K. Hodges. 1999. The mean evolution and variability of the Asian summer monsoon: Comparison of ECMWF and NCEP–NCAR reanalyses. Mon. Wea. Rev. 127:11571186.

    • Search Google Scholar
    • Export Citation
  • Basu, B. K. 2001. Simulation of the summer monsoon over India in the ensemble of seasonal simulations from the ECMWF reanalyzed data. J. Climate 14:14401449.

    • Search Google Scholar
    • Export Citation
  • Basu, B. K. 2003. Verification of model predicted precipitation over India during the summer monsoon of 1997. Mausam 53:359376.

  • Basu, B. K., , K. J. Ramesh, , and P. A. Harathi. 1999. Intercomparison of the characteristic features of the Southwest monsoon over India as reproduced in the mean monthly analyses and forecasts of some operational NWP centres during 1995. Meteor. Atmos. Phys. 69:157178.

    • Search Google Scholar
    • Export Citation
  • Challinor, A. J., , J. M. Slingo, , T. R. Wheeler, , P. Q. Craufurd, , and D. I. F. Grimes. 2003. Toward a combined seasonal weather and crop productivity forecasting system: Determination of the working spatial scale. J. Appl. Meteor. 42:175192.

    • Search Google Scholar
    • Export Citation
  • Das, P. K. 1962. Mean vertical motion and non-adiabatic heat source over India during the monsoon. Tellus 14:212220.

  • Drosdowsky, W., and H. Zhang. 2003. Forecast Verification—A Practitioner’s Guide in Atmospheric Science. John Wiley and Sons, 240 pp.

  • ECMWF cited. 1997. Operational precipitation forecast data. [Available online at http://www.ecmwf.int/products/data/.].

  • Gadgil, S., and S. Sajani. participating AMIP modeling groups. 1998. Monsoon precipitation in the AMIP runs. Climate Dyn. 14:659689.

  • Gadgil, S., , P. S. R. Rao, , and K. N. Rao. 2002. Use of climate information for firm-level decision making: Rain fed groundnut in southern India. Agric. Syst. 74:431457.

    • Search Google Scholar
    • Export Citation
  • Ghosh, S. K., , M. C. Pant, , and B. N. Dewan. 1978. Influence of the Arabian Sea on the Indian summer monsoon. Tellus 30:117125.

  • Goswami, B. N., and R. S. Ajaya Mohan. 2001. Intraseasonal oscillations and interannual variability of the Indian summer monsoon. J. Climate 14:11801198.

    • Search Google Scholar
    • Export Citation
  • Hansen, J. W. 2002. Realizing the potential benefits of climate prediction to agriculture: Issues, approaches, challenges. Agric. Syst. 74:309330.

    • Search Google Scholar
    • Export Citation
  • IMD 1981. Part ARainfall. Climatological Atlas of India, Office of the DDG, 63 pp.

  • IMD 1995. Monsoon season—1995. Climate Diagnostic Bulletin of India, Office of the ADGM, 21 pp.

  • IMD 1996. Monsoon season—1996. Climate Diagnostic Bulletin of India, Office of the ADGM, 23 pp.

  • IMD 1997. Monsoon season—1997. Climate Diagnostic Bulletin of India, Office of the ADGM, 22 pp.

  • IMD 2002. Forecasting circular. Office of the DDGM Rep. W-969/4496–4570, 3 pp.

  • Kalnay, E., , J. G. Sela, , K. A. Campana, , B. K. Basu, , M. D. Schwarzkopf, , P. E. Long, , P. M. Caplan, , and J. C. Alpert. 1988. Documentation of research version of the NMC Medium Range Forecasting Model. National Meteorological Center, 132 pp.

  • Krishnamurthy, V., and J. Shukla. 2000. Intraseasonal and interannual variability of rainfall over India. J. Climate 13:43664377.

  • Kuo, H. L. 1974. Further studies of the parameterization of the influence of cumulus convection on large-scale flow. J. Atmos. Sci. 31:12321240.

    • Search Google Scholar
    • Export Citation
  • Manabe, S., , J. Smagorinsky, , and R. F. Strickler. 1965. Simulated climatology of a general circulation model with a hydrologic cycle. Mon. Wea. Rev. 93:769798.

    • Search Google Scholar
    • Export Citation
  • Mukherjee, A. K., and B. Shyamala. 1986. Distant effect of monsoon depressions: Part 1–Effect of formation of depressions on rainfall activity along the west coast of India. Mausam 36:429434.

    • Search Google Scholar
    • Export Citation
  • Murphy, A. H., and R. L. Winkler. 1987. A general framework for forecast verification. Mon. Wea. Rev. 115:13301338.

  • Parthasarathy, B., , K. Rupakumar, , and A. A. Munot. 1992. Forecast of rainy-season foodgrain production based on monsoon rainfall. Indian J. Agric. Sci. 62:18.

    • Search Google Scholar
    • Export Citation
  • Rao, Y. P. 1976. Southwest monsoon. Synoptic Meteorology,Meteor. Monogr., No. 1, India Meteorological Department, 135 pp.

  • Singh, S. V., , R. H. Kripalani, , and D. R. Sikka. 1992. Interannual variability of the Madden–Julian oscillations in Indian summer monsoon rainfall. J. Climate 5:973978.

    • Search Google Scholar
    • Export Citation
  • Sperber, K. R., , J. M. Slingo, , and H. Annamalai. 2000. Predictability and the relationship between subseasonal and interannual variability during the Asian summer monsoon. Quart. J. Roy. Meteor. Soc. 126C:25752584.

    • Search Google Scholar
    • Export Citation
  • Tiedtke, M. 1983. The sensitivity of the time–mean large-scale flow to cumulus convection in the ECMWF model. Proc. ECMWF Workshop on Convection in Large-Scale Numerical Models, Reading, United Kingdom, ECMWF, 297–316.

  • Upadhyay, D. S., , S. Kaur, , M. S. Misra, , and M. K. Gupta. 1990. Space correlation structure of rainfall over India. Mausam 41:523530.

  • Webster, P. J., , V. O. Magalia, , T. N. Palmer, , J. Shukla, , R. A. Tomas, , M. Yanai, , and T. Yasunari. 1998. Monsoon processes, predictability and the prospect for prediction. J. Geophys. Res. 103:1445114510.

    • Search Google Scholar
    • Export Citation
  • WMO 1992. Manual on the Global Data Processing System, Attachment II-7. WMO Rep. 485, 37 pp.

  • WMO 1994. Guide to hydrological practices. WMO Rep. 168, 735 pp.

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Some Characteristics of Model-Predicted Precipitation during the Summer Monsoon over India

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Abstract

For the summer monsoon seasons of 1995, 1996, and 1997 the day-1 to day-4 forecasts of precipitation from both the National Centre for Medium Range Weather Forecasting (NCMRWF) and the European Centre for Medium-Range Forecasts (ECMWF) models reproduce the main features of the observed precipitation pattern when averaged over the whole season. On average, less than 30% of all rain gauge stations in India report rain on a given day during the monsoon season. The number of observed rainy days increases to 41% after spatial averaging over ECMWF model grid boxes and to 50% after spatial averaging over NCMRWF model grid boxes. The NCMRWF model forecasts have 10%–15% more rainy days, mostly in the light or moderate precipitation categories, when compared with the spatial average of observed values. Seasonal accumulated values of all of India’s average precipitation show a slight increase with the forecast lead time for the NCMRWF model and a small decrease for the ECMWF model. The weekly accumulated values of forecast precipitation from both models, averaged over the whole of India, are in good phase relationship (∼0.9 in most cases) with the observed value for forecasts with a lead time up to day 4. Values of statistical parameters, based on the frequency of occurrence in various classes, indicate that the NCMRWF model has some skill in predicting precipitation over India during the summer monsoon. The NCMRWF model forecasts have higher trend correlation with the observed precipitation over India than do the ECMWF model forecasts. The mean error in precipitation is, however, much less in the ECMWF model forecasts, and the spatial distribution of seasonal average medium-range forecasts of ECMWF is closer to that observed along the west coast mountain ridgeline.

Corresponding author address: B. K. Basu, NCMRWF, A50, Institutional Area, Sector-62, Noida, UP. 201 301, India. bkbasu@ncmrwf.gov.in

Abstract

For the summer monsoon seasons of 1995, 1996, and 1997 the day-1 to day-4 forecasts of precipitation from both the National Centre for Medium Range Weather Forecasting (NCMRWF) and the European Centre for Medium-Range Forecasts (ECMWF) models reproduce the main features of the observed precipitation pattern when averaged over the whole season. On average, less than 30% of all rain gauge stations in India report rain on a given day during the monsoon season. The number of observed rainy days increases to 41% after spatial averaging over ECMWF model grid boxes and to 50% after spatial averaging over NCMRWF model grid boxes. The NCMRWF model forecasts have 10%–15% more rainy days, mostly in the light or moderate precipitation categories, when compared with the spatial average of observed values. Seasonal accumulated values of all of India’s average precipitation show a slight increase with the forecast lead time for the NCMRWF model and a small decrease for the ECMWF model. The weekly accumulated values of forecast precipitation from both models, averaged over the whole of India, are in good phase relationship (∼0.9 in most cases) with the observed value for forecasts with a lead time up to day 4. Values of statistical parameters, based on the frequency of occurrence in various classes, indicate that the NCMRWF model has some skill in predicting precipitation over India during the summer monsoon. The NCMRWF model forecasts have higher trend correlation with the observed precipitation over India than do the ECMWF model forecasts. The mean error in precipitation is, however, much less in the ECMWF model forecasts, and the spatial distribution of seasonal average medium-range forecasts of ECMWF is closer to that observed along the west coast mountain ridgeline.

Corresponding author address: B. K. Basu, NCMRWF, A50, Institutional Area, Sector-62, Noida, UP. 201 301, India. bkbasu@ncmrwf.gov.in

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