Real-time dynamical index for the large-scale South Asian monsoon
Webster and Yang (1992) defined an index for the intensity of the South Asian monsoon as the vertical shear of the horizontal mean zonal wind [u(200 hPa) - u(850 hPa)] in the region (40 E-110 E, 0-20 N). The plots below are based on NCEP operational analyses for the current year, and NCEP reanalysis data for previous years and the climatology.
Reference: Webster, P. J., and S. Yang, 1992: Q. J. R. Meteorol. Soc., 118, pp. 877-926.
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