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Methodology

The BSISO indices used in this activity have been newly developed by Lee at al. (2013). The philosophy behind these newly developed indices is similar to the Real-time Multivariate MJO(RMM) indices of Wheeler and Hendon (2004), except that the focus is on the intraseasonal variability that is specific to the Asian monsoon region. In particular, the new indices capture the observed northward propagation that occurs in the Asian monsoon, as well as higher frequency (periods of 10-30 days) components exhibiting a Rossby wave like character. Two propagating modes, each comprising a pair of multivariate empirical orthogonal functions, are used to capture this variability, and are respectively called BSISO1 and BSISO2. BSISO1 captures the canonical northward-propagating BSISO component and BSISO2 captures the higher-frequency pre-monsoon and onset component.

BSISO1

Figure 1. The life cycle composite of OLR (shading) and 850-hPa wind (vector) 
anomaly reconstructed based on PC1 and PC2 of BSISO1 in 8 phases.

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BSISO2

Figure 2. Same as Figure 1 except for PC3 and PC4 of BSISO2.

The table below summarizes the data requested by the MJOWG for the operational centers. For additional details regarding the data and methodology, see the document link below the table. This document includes background information and motivation for this activity along with directions for interested operational centers who wish to participate in this project.

 

FieldsOLR, and U850 totals (anomaly fields optional) Initial analysis, 
forecasts of all ensemble members, out to no more than 40 days
Resolution2.5° in latitude (10°S, 7.5°S, 5°S, ....40°N) and longitude (40°E, 42.5°E. 45.0°E, ......160°E). 
Daily averaged (00-24Z).
Update FrequencyDaily, or less for those systems run at a reduced frequency 
Additional data during initial transfer (i.e., send analysis data for past 120 days)
Additional dataAt beginning of transfer, send analysis data for past 120 days.
FormatASCII

 

Further Information -- Working Group on Numerical experimentation (WGNE) Letter 

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References

Gottschalck, J., M. Wheeler, K. Weickmann, F. Vitart, N. Savage, H. Lin, H. Hendon, D. Waliser, K. Sperber, M. Nakagawa, C. Prestrelo, M. Faltau, and W. Higgins, 2010: A Framework for Assessing Operational Madden-Julian Oscillation Forecasts: A CLIVAR MJO Working Group project. Bull. Amer. Met. Soc., 91, 1247-1258.

Lee, J.-Y., B. Wang, M. C. Wheeler, X. Fu, D.E. Waliser, and I.-S. Kang, 2013: Real-time multivariate indices for the boreal summer intraseasonal oscillation over the Asian summer monsoon region. Clim. Dyn., 40, 493-509. 
Wheeler M. and H. Hendon, 2004: An All-Season Real-Time Multivariate MJO Index: Development of an Index for Monitoring and Prediction. Monthly Weather Review, 132, 1917-1932.
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