Seasonal Variations of the Relationship Between Some Enso Parameters and Indian Rainfall

Prasad, K. D.; Singh, S. V.

doi:10.1002/(sici)1097-0088(199608)16:8<923::aid-joc62>3.0.co;2-5

Cited by 3 publications

(2 citation statements)

References 23 publications

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“…During the year after an El Nin ˜o, the summer rainfall over the western North Pacific (WNP) tends to decrease (Wang et al 2000) while the east Asian subtropical front precipitation tends to enhance (Chen et al 1992;Chang et al 2000;Lau and Weng 2001). It was also found that during the mature phase of ENSO (boreal winter), the deficient Australian monsoon rainfall follows a weak Indian summer monsoon (ISM; e.g., Meehl 1987), whereas the rainfall increases over India (Prasad and Singh 1996) and southern China (Zhang et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Atmosphere–Warm Ocean Interaction and Its Impacts on Asian–Australian Monsoon Variation*

Wang¹,

Wu²,

Li³

2003

J. Climate

659

465

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Asian-Australian monsoon (A-AM) anomalies depend strongly on phases of El Nin ˜o (La Nin ˜a). Based on this distinctive feature, a method of extended singular value decomposition analysis was developed to analyze the changing characteristics of A-AM anomalies during El Nin ˜o (La Nin ˜a) from its development to decay. Two off-equatorial surface anticyclones dominate the A-AM anomalies during an El Nin ˜oone over the south Indian Ocean (SIO) and the other over the western North Pacific (WNP). The SIO anticyclone, which affects climate conditions over the Indian Ocean, eastern Africa, and India, originates during the summer of a growing El Nin ˜o, rapidly reaches its peak intensity in fall, and decays when El Nin ˜o matures. The WNP anticyclone, on the other hand, forms in fall, attains maximum intensity after El Nin ˜o matures, and persists through the subsequent spring and summer, providing a prolonged impact on the WNP and east Asian climate. The monsoon anomalies associated with a La Nin ˜a resemble those during an El Nin ˜o but with cyclonic anomalies. From the development summer to the decay summer of an El Nin ˜o (La Nin ˜a), the anomalous sea level pressure, low-level winds, and vertical motion tend to reverse their signs in the equatorial Indian and western Pacific Oceans (10ЊS-20ЊN, 40Њ-160ЊE). This suggests that the tropospheric biennial oscillation is intimately linked to the turnabouts of El Nin ˜o and La Nin ˜a.The remote El Nin ˜o forcing alone can explain neither the unusual amplification of the SIO anticyclone during a developing El Nin ˜o nor the maintenance of the WNP anticyclone during a decaying El Nin ˜o. The atmosphere-ocean conditions in the two anticyclone regions are similar, namely, a zonal sea surface temperature (SST) dipole with cold water to the east and warm water to the west of the anticyclone center. These conditions result from positive feedback between the anomalous anticyclone and the SST dipole, which intensifies the coupled mode in the SIO during El Nin ˜o growth and maintains the coupled mode in the WNP during El Nin ˜o decay. The interactions in the two anticyclone regions share common wind evaporation/entrainment and cloud-radiation feedback processes but they differ with regard to the oceanic dynamics (vertical and horizontal advection and thermocline adjustment by oceanic waves). The outcome of the interactions in both regions, however, depends crucially on the climatological surface winds. The SIO-coupled mode is triggered by El Nin ˜o-induced subsidence and alongshore winds off the coast of Sumatra. However, other independent El Nin ˜o local and remote forcing can also trigger this coupled mode.The traditional view has regarded SST anomalies in the Indian and western Pacific Oceans as causing the A-AM variability. The present analysis suggests that the SST anomalies in these warm ocean regions are, to a large extent, a result of anomalous monsoons. Thus, the atmosphere-warm ocean interaction may significantly modify the impacts of remote El Nin ˜o forcing and should be ...

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Section: Introductionmentioning

confidence: 99%

Atmosphere–Warm Ocean Interaction and Its Impacts on Asian–Australian Monsoon Variation*

Wang¹,

Wu²,

Li³

2003

J. Climate

659

465

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“…For comprehensive overviews of research on the Asian monsoons the reader is referred to the following volumes: Das 1986;Fein & Stephens 1987;Chang & Krishnamurti 1987;Ding 1994. Spatial variability of precipitation and temperature in the Asian monsoon region has been studied chiefly within the following contexts: 1) within political boundaries, e.g., the spatial variability of India or China monsoon rainfall (e.g., Shukla 1987;Singh et al 1991;Hulme et al 1994;Liang et al 1995); 2) the relationship between the all-India monsoon rainfall (IMR) and Mei Yu rainfall (e.g., Fu & Fletcher 1988;Fu & Ye 1988;Yang & Gutowski 1992;Kripalani & Singh 1993); 3) as related to EI Niiio-Southern Oscillation (henceforth, ENSO; see Allan et al 1996 for a comprehensive treatment of this subject) (e.g., Rasmusson & Carpenter 1983;Mooley & Parthasarathy 1983;Wang & Li 1990, Prasad & Singh 1996 (note: recently, the International Research Institute for Climate Prediction [IRI] has produced ENSO-precipitation impact studies for monsoon Asia and Australia, available on the WWW at http://iri.ucsd.edu/research/ENSO/enso.html). Relatively few studies have examined c1imate variations between different regions within monsoon Asia (Hakkarinen & Landsberg 1981;Garfin 1992;Kripalani et al 1995;Kripalani & Kulkarni 1997).…”

Section: Introductionmentioning

confidence: 99%

Interannual Variability of Asian Monsoon Precipitation, 1953-1982, Using Instrumental Records

Garfin-Woll¹

1999

IAWA J

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Instrumental records were used to assess the interannual variability of precipitation for the greater Asian monsoon region (50°N-15°S, 60°E-150°E). Correlation analysis shows intriguing teleconnections between subtropical and midlatitude precipitation regions. Principal components analyses show that ENSO (EI Niño-Southern Oscillation) is the dominant factor associated with recent interannual variation of precipitation in the region. The strongest relationships between ENSO and boreal summer precipitation were found in subtropical regions, as weIl as North Central China and southeastern Kazakhstan; boreal winter precipitation in the tropics and subtropics also exhibited strong relationships with ENSO. Scenarios for reconstructing spatial and temporal patterns of Asian monsoon precipitation variation were generated by selecting individual records based on 1) correlation with regional time series and 2) length of record. Spatial patterns were highly dependent on the type of record selected; however, temporal patterns were reasonably weIl reproduced regardless of station selection criteria. The implication of the latter result is that the dominant modes of boreal summer and winter precipitation for East Asia might be reconstructed using relatively few sites.

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Influence of Eurasian spring snow cover on Asian summer rainfall

Liu

Yanai

2002

Intl Journal of Climatology

128

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The Eurasian snow cover anomaly in spring has been considered as one of the important factors affecting Asian summer monsoon variability. Using the long time series of Eurasian spring (March-April) snow cover (ESSC) reconstructed by Brown (2000. Journal of Climate 13: 2339) and snow cover (1973-98) and depth (1979-87) data from satellite observation, the influences of ESSC on the all-India monsoon (June-September) rainfall (AIMR) and the summer rainfall over all parts of Asia are examined. It is found that the statistical relation between AIMR and ESSC changes over a multi-decadal time scale. The negative correlation between them has increased markedly since the mid 1970s. The region where the summer rainfall has the strongest and most stable negative correlation with the preceding ESSC is located in northern Mongolia, south of Lake Baikal. The correlation between the summer rainfall and ESSC increases after the data are treated with a low-pass filter, showing that the impact of snow cover may be seen more clearly with the removal of the effect of El Niño-southern oscillation. Comparative analyses for contrasting years with excessive and deficient snow cover show that the anomalies of ESSC occur mainly in northwestern Eurasia. In the years of excessive ESSC anomalies, cooling and a cyclonic circulation anomaly in the lower troposphere appear over the northern part of Eurasia, leading to a Rossby-wave-train-like circulation response, then a weakened East Asia summer monsoon and deficient rainfall with an anticyclonic circulation anomaly south of Lake Baikal. Anomalies with opposite signs occur in the years of deficient snow cover.

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Seasonal Variations of the Relationship Between Some Enso Parameters and Indian Rainfall

Cited by 3 publications

References 23 publications

Atmosphere–Warm Ocean Interaction and Its Impacts on Asian–Australian Monsoon Variation*

Atmosphere–Warm Ocean Interaction and Its Impacts on Asian–Australian Monsoon Variation*

Interannual Variability of Asian Monsoon Precipitation, 1953-1982, Using Instrumental Records

Influence of Eurasian spring snow cover on Asian summer rainfall

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