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South Asian Summer Monsoon Index (SASMI)
The South Asian summer monsoon index (SASMI) is defined as an area-averaged seasonally (JJAS) dynamical normalized seasonality (DNS) at 850 hPa within the South Asian domain (5°-22.5°N, 35°-97.5°E) (Li and Zeng, 2002, 2003, 2005).
The SASM contains two independent components, SASM1 over the South Asian region 1 (2.5°-20°N, 35°-70°E) and SASM2 over the South Asian region 2 (2.5°-20°N, 70°-110°E), with quite different dynamical influences on the monsoon rainfall over the South Asia (Wang and Fan, 1999; Li and Zeng, 2002). The summer monsoon indices over the South Asian Regions 1 and 2 are abbreviated to SASMI1 and SASMI2, respectively.
The South Asian Summer Monsoon Index (SASMI)
The normalized time series of SASMI (a), SASMI1 (b) and SASMI2 (c) for the period of 1948-2009.
The summer here is JJAS. The thick solid lines indicate 9-year Gaussian-type filtered values.
Correlation maps between the seasonal (June-September) rainfall over the South Asian and (a) SASMI, (b) SASMI1, and (c) SASMI2 for the period of 1979-97. The shaded areas indicate significant at the 95% confidence level.
Correlation between precipitation and the SASMI (shading) and regression of 850-mb winds against the monsoon index (vectors) for June, July, August and September from 1979 to 2006, respectively. The shaded areas and vectors indicate significant at the 95% confidence level.
Correlation between precipitation and the SASMI1 (shading) and regression of 850-mb winds against the monsoon index (vectors) for June, July, August and September from 1979 to 2006, respectively. The shaded areas and vectors indicate significant at the 95% confidence level.
Correlation between precipitation and the SASMI2 (shading) and regression of 850-mb winds against the monsoon index (vectors) for June, July, August and September from 1979 to 2006, respectively. The shaded areas and vectors indicate significant at the 95% confidence level.
Related
References
Li, J. and Q. Zeng, 2005: A new monsoon index, its interannual variability and relation with monsoon precipitation. Climatic and Environmental Research, 10(3): 351-365. Electronic version PDF
Li, J. and Q. Zeng, 2003: A new monsoon index and the geographical distribution of the global monsoons, Adv. Atmos. Sci., 20, 299-302. Electronic version PDF
Li, J. and Q. Zeng, 2002: A unified monsoon index, Geophysical Research Letters, 29(8), 1274, doi:10.1029/2001GL013874. Electronic version PDF
Li, J., and Q. Zeng, 2000: Significance of the normalized seasonality of wind field and its rationality for characterizing the monsoon, Science in China (D), 43(6): 647-653. Electronic version PDF
Wang, B., and Z. Fan, 1999: Choice of South Asian summer monsoon indices, Bull. Amer. Meteor. Soc., 80, 629-638.
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5 kilobytes |
South Asian Summer Monsoon Index (SASMI) |
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5 kilobytes |
Summer Monsoon Index over South Asian Region 1 (SASMI1) |
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5 kilobytes |
Summer Monsoon Index over South Asian Region 2 (SASMI2) |
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You can download this file from here (right-click then select "Save Target As" or "Save Link As"). |
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File format |
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for year = 1948 to 2009 format (1x, i4, 10f7.3) year, Jun, Jul, Aug, Sep, and summer (JJAS) raw values, Jun, Jul, Aug, Sep, and summer (JJAS) normalized values |
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Note: Missing values represented by 99.99. |
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The Daily South Asian Summer Monsoon Index (SASMI) Data will soon be available |
Last updated: 2010-01-15 (Jianping Li: ljp@lasg.iap.ac.cn)