Indian summer monsoon rainfall and its link with ENSO and Indian Ocean climate indices

Ihara, Chie; Kushnir, Yochanan; Cane, Mark A.; Peña, Víctor H. de la

doi:10.1002/joc.1394

Cited by 123 publications

(89 citation statements)

References 25 publications

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“…A monthly index of zonal surface wind for the equatorial Indian Ocean (EQWIN) is based on ICOADS data for anomalies averaged over 62°-90°E, 4°N-4°S, for 1884-1997 (Worley et al, 2005). EQWIN is a sensitive indicator of Indian Ocean climate which has been utilized to improve a simple predictive model of the Indian monsoon based on Niño-3 SST, while the DMI did not show a strong relationship (Gadgil et al, 2004;Ihara et al, 2007). Rainfall data were obtained from the GPCC Variability Analysis of Surface Climate Observations (Beck et al, 2005, Vasclim-0 0.5, 1951-2000 precipitation data set.…”

Section: Methodsmentioning

confidence: 99%

El Niño and Indian Ocean influences on Indonesian drought: implications for forecasting rainfall and crop productivity

D’Arrigo

Wilson

2008

Intl Journal of Climatology

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Indonesia is impacted by severe droughts that cause major food shortages over much of the country, and have long been linked with El Niño events in the tropical Pacific Ocean. Despite seasonal forecasts based on relatively complex climate models, the 1997-1998 'El Niño of the century' was still followed by huge shortfalls in crop production (e.g. a loss of 3 million tons of rice in Java alone), reflecting the large gap that can exist between these forecasts and their actual utilization in agricultural planning. Alternatively, simple predictive models of rainfall and crop yields for Indonesia and other Indian Ocean rim countries have utilized an index of equatorial Pacific sea surface temperatures (Niño-3.4 SST), and related this index directly to indices of rainfall and crop productivity. However, these latter models have not included climatic information from the Indian Ocean, also implicated as a likely cause of drought in western Indonesia. Here we show that an index of Indian Ocean SSTs, when combined with the previously utilized Niño-3.4 SSTs, provides a significantly more accurate model of Sept-Dec drought (PDSI) over Java, Indonesia, than Niño-3.4 SSTs alone (ar 2 64.5% vs 37.9%). Based solely on data for the month of August, this model provides the best tradeoff between model skill and adequate lead time for the Sept-Dec rice planting season. Such simple models can be used to generate readily usable early warning forecasts of drought and crop failure risk in Indonesia, particularly in the western part of the country that is most influenced by Indian Ocean climate variability.

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Section: Methodsmentioning

confidence: 99%

El Niño and Indian Ocean influences on Indonesian drought: implications for forecasting rainfall and crop productivity

D’Arrigo

Wilson

2008

Intl Journal of Climatology

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“…Gadgil et al ( , 2004 showed that there is a strong relationship between the extremes (droughts and excess monsoon seasons) and a composite index which is a linear combination of the ENSO index and EQWIN. Using a longer dataset (from 1881 to 1998), Ihara et al (2007) showed that the variation of ISMR is better described by the use of indices of ENSO as well as EQWIN than by ENSO index alone. The inference of Krishnamurthy and Shukla (2008) on the importance of these two modes for interannual variation of the monsoon is consistent with these studies demonstrating the importance of ENSO and EQUINOO.…”

Section: Intraseasonal and Interannual Variations Of Ismrmentioning

confidence: 97%

Active and break spells of the Indian summer monsoon

2010

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In this paper, we suggest criteria for the identification of active and break events of the Indian summer monsoon on the basis of recently derived high resolution daily gridded rainfall dataset over India . Active and break events are defined as periods during the peak monsoon months of July and August, in which the normalized anomaly of the rainfall over a critical area, called the monsoon core zone exceeds 1 or is less than −1.0 respectively, provided the criterion is satisfied for at least three consecutive days. We elucidate the major features of these events. We consider very briefly the relationship of the intraseasonal fluctuations between these events and the interannual variation of the summer monsoon rainfall.We find that breaks tend to have a longer life-span than active spells. While, almost 80% of the active spells lasted 3-4 days, only 40% of the break spells were of such short duration. A small fraction (9%) of active spells and 32% of break spells lasted for a week or longer. While active events occurred almost every year, not a single break occurred in 26% of the years considered. On an average, there are 7 days of active and break events from July through August. There are no significant trends in either the days of active or break events. We have shown that there is a major difference between weak spells and long intense breaks. While weak spells are characterized by weak moist convective regimes, long intense break events have a heat trough type circulation which is similar to the circulation over the Indian subcontinent before the onset of the monsoon.The space-time evolution of the rainfall composite patterns suggests that the revival from breaks occurs primarily from northward propagations of the convective cloud zone. There are important differences between the spatial patterns of the active/break spells and those characteristic of interannual variation, particularly those associated with the link to ENSO. Hence, the interannual variation of the Indian monsoon cannot be considered as primarily arising from the interannual variation of intraseasonal variation. However, the signature over the eastern equatorial Indian Ocean on intraseasonal time scales is similar to that on the interannual time scales.

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“…El Niño events (warmer than normal sea surface temperature (SST) in the eastern equatorial Pacific) are linked to a deficit in the all-India summer monsoon rainfall (Ihara et al, 2007 and see references therein). However, El Niño's influence on the monsoon is not always proportional to its strength.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies propose that the Indian Ocean Dipole (IOD) mode (Saji et al, 1999;Webster et al, 1999) and the related phenomena explain unusual monsoon behaviour during El Niño (Ashok et al, 2001(Ashok et al, , 2004Gadgil et al, 2003Gadgil et al, , 2004Ihara et al, 2007). Ihara et al (2007) discussed an association between climate anomalies over the Indian Ocean, summer monsoon rainfall and El Niño, however, they did not find a statistically significant association between the all-India summer monsoon rainfall, area-weighted averaged total rainfall of the summer monsoon season obtained from the raingauge stations over entire India, and the June-September IOD-mode index based on SST anomalies from 1881 to 1998. In general, it is known that some parts of the Indian Ocean SSTs are influenced by both ENSO (Klein et al, 1999 and many others) and the monsoon circulation (Shukla, 1987).…”

Section: Introductionmentioning

confidence: 99%

July droughts over Homogeneous Indian Monsoon region and Indian Ocean dipole during El Niño events

Ihara

Kushnir

2008

Intl Journal of Climatology

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The monthly summer monsoon rainfall over the Homogeneous Indian Monsoon region (HI) that represents most of the variance of all‐India monsoon rainfall is investigated using observational data from 1880 to 2002. Severe droughts in July occur mostly during El Niño events of the boreal summer monsoon season. They occurred frequently in the late 19th to early 20th century, rarely in the middle of the 20th century, and again occasionally occurred after the 1960s.During El Niño events, severe droughts in July over HI are significantly associated with smaller sea surface temperature‐ (SST) based Indian Ocean Dipole mode index (SSTDMI) in May and July compared to the years without these outstanding events. The evolution of SSTDMI that usually starts around May/June during El Niño events tends to delay when July precipitation over HI is abnormally low. Niño3 values from May through October are not significantly associated with severe droughts over HI in July during El Niño events indicating that the strength of El Niño events is not related to the occurrences of severe droughts in July. Copyright © 2008 Royal Meteorological Society

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Indian summer monsoon rainfall and its link with ENSO and Indian Ocean climate indices

Cited by 123 publications

References 25 publications

El Niño and Indian Ocean influences on Indonesian drought: implications for forecasting rainfall and crop productivity

El Niño and Indian Ocean influences on Indonesian drought: implications for forecasting rainfall and crop productivity

Active and break spells of the Indian summer monsoon

July droughts over Homogeneous Indian Monsoon region and Indian Ocean dipole during El Niño events

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