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HOME > Climate System Monitoring > Asian Monsoon Monitoring > Explanation

Explanation on the Products for Asian Monsoon Monitoring

   JMA provides various products that are useful in monitoring Asian monsoon. These products and data are introduced below.


   The atmospheric circulation data are the Japanese 55-year Reanalysis (JRA-55) (Kobayashi et al. 2015). Tropical convective activity is inferred from outgoing longwave radiation (OLR) data provided by the National Oceanic and Atmospheric Administration (NOAA). For details of these datasets, please refer to "Explanation on the Products for Climate System Monitoring". The base period for the normal is 1991-2020.

Animation Maps

   The Animation Maps web pages are useful to analyze the time evolution of atmospheric circulation and tropical convective activity.
   The web pages cover four areas: the Asian Region, the Northern Hemisphere, the Southern Hemisphere and the Global Area. Data for use in monitoring tropical convective activity and circulation (such as OLR, velocity potential and stream function) are available on the Asian Region and Global Area pages, and data on major elements for use in monitoring extratropical circulation (such as sea level pressure, 500 hPa geopotential height and 850 hPa temperature) shown on polar stereographic charts are available on the Northern Hemisphere and Southern Hemisphere pages, Animation Maps are available for the period from 1958 to two days prior, and are updated every day. Please refer to the detail explanation document.

Monitoring Indices

   Products The Monitoring Indices web pages provide monthly ENSO and Asian monsoon monitoring indices (such as Southern Oscillation Index (SOI), equatorial zonal wind index, area averaged OLR index) and daily time series of Asian monsoon monitoring indices (such as area averaged vertical zonal wind shear (Webster and Yang 1992) and OLR (Wang and Fan 1999)). These products are useful in monitoring the strength and expansion of the summer monsoon.

Time Cross Sections

   Time-longitude cross sections of three and seven day mean OLR, velocity potential, zonal wind and SST are useful in monitoring intraseasonal oscillations of and related to the Asian monsoon. These products are available for the period since 1979, and are updated every day.


  • Kobayashi, S., Y. Ota, Y. Harada, A. Ebita, M. Moriya, H. Onoda, K. Onogi, H. Kamahori, C. Kobayashi, H. Endo, K. Miyaoka, and K. Takahashi, 2015: The JRA-55 Reanalysis: General Specifications and Basic Characteristics. J. Meteorol. Soc. Japan, 93, 5-48.
  • Wang, B., and Z. Fan, 1999: Choice of South Asian Summer Monsoon Indices. Bull. Amer. Meteor. Sci., 80, 629-638.

  • Webster, P. J. and S. Yang, 1992: Monsoon and ENSO: Selectively Interactive Systems. Quart. J. Roy. Meteor. Soc., 118, 877-926.