Delayed onset of the 2002 Indian monsoon

Flatau, Maria; Flatau, Piotr J.; Schmidt, Jerome M.; Kiladis, George N.

doi:10.1029/2003gl017434

Cited by 53 publications

(50 citation statements)

References 10 publications

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“…On the other hand, Teng and Wang (2003) indicate a much more robust relationship of significant positive relationship with interannual eastern Pacific SST variability for the westward propagating component of the ISO; (2) the intraseasonal ''cloudiness fluctuations'' exhibited longer periods during El Nino years (Yasunari 1980). The character of the monsoon may be influenced via the ENSO-related sensitivity of the northwestward propagating component of the ISO and variations of the boreal summer ISO (Teng and Wang 2003;Flatau et al 2003). But, there is still a need to sort out more clearly the effects from ENSO; and (3) the interannual and intraseasonal fluctuations share a common mode of spatial variability as indicated in Section 2.…”

Section: Intraseasonal Variability (Isv)mentioning

confidence: 99%

The Variability of the Asian Summer Monsoon

Ding

2007

Journal of the Meteorological Society of Japan

235

150

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The Asian monsoon is the most significant component of the global climate system. During recent two decades, a more and more efforts have been made to study the Asian monsoon. A substantial achievement has been made in basic physical processes, predictability and prediction since the MONEX of [1978][1979]. The major advance in our new understanding of the variability of the Asian summer monsoon has been highlighted in this paper. The present paper is structured with four parts. The first part is the introduction, indicating the new regional division of the Asian monsoon system and significant events of the history of the Asian monsoon research. The second part discusses the annual cycle and seasonal march of the Asian monsoon as the mean state, with a special emphasis on the onset, propagation, active-break cycle and withdrawal of the Asian summer monsoon. The process and mechanism of the earliest onset of the Asian summer monsoon which takes place in the near-equatorial East Indian ocean-central and southern Indochina Peninsula have been well documented. The third part deals with the multiple scale variability of the Asian summer monsoon, including the intraseasonal, interannual and inter-decadal variability. Their dominant modes such as 10-20 day and 30-60 day oscillations for the intraseasonal variability, the Tropospheric Biennial Oscillation (TBO), the Indian Ocean Dippole Mode (IODM) and teleconnection patterns for interannual variability and the 60-year oscillation for the inter-decadal variability, as well as related SST-monsoon relationship and land-monsoon relationship have been discussed in more details. The fourth part is the conclusion, summarizing the major findings and proposing future work.

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Section: Intraseasonal Variability (Isv)mentioning

confidence: 99%

The Variability of the Asian Summer Monsoon

Ding

2007

Journal of the Meteorological Society of Japan

235

150

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“…The tendencies of false onset can be noted in zone 4 in northern India and zones 6 and 7 in southern India, where pentad rainfall above 1.5 cm is noted in the first few pentads. This pre-onset rainfall can be attributed to the convection associated with the quadruplet cyclones observed in the Indian Ocean after 9 May 2002 and the subsequent depression over the Bay of Bengal (Flatau et al, 2003). Ignoring this rainfall, the time series of pentad rainfall in 2002 indicates an abrupt and sustained increase in pentad rainfall from about 1.5 cm at around 18 June in zone 1, 15 June in zone 2, 22 June in zone 3, 12 June in zone 4, 9 June in zone 5, 29 May in zone 6 and 6 June in zone 7, indicating onset of the monsoon in different zones.…”

Section: Analysis Of the 10-year Compositementioning

confidence: 99%

“…Compared with IMD data, though the onset times are not degraded in any of the zones, the errors introduced in onset-phase rainfall amount in zones 5 and 7 over NNRP precipitation data suggest the need for improvements in the model setup such as an increase in resolution to resolve the topographic effects. (Flatau et al, 2003;Joseph et al, 2006) showed that it was a false monsoon onset associated with propagating tropical intra-seasonal disturbances/cyclones unrelated to the monsoon onset. In contrast, the monsoon in 2009 was weak, characterized by drought across all of India, and its onset occurred earlier by 1 week (onset on 23 May) (Puranik et al, 2013).…”

Section: Analysis Of the 10-year Compositementioning

confidence: 99%

“…An important phenomenon during the onset phase is a sudden increase of kinetic energy (KE) over the low-level jet (LLJ) region (55-65 • E, 5-15 • N) which is associated with a subsequent enhancement in precipitation over the monsoon region (70-110 • E, 10-30 • N) (Goswami, 2012). The interannual variability of the onset phase is related to, among others, sea surface temperatures (SSTs) over the south tropical Indian Ocean and western equatorial Pacific (Flatau et al, 2003;Joseph et al, 1994). The onset of ISM occurs through the progression of its two currents i.e., the Arabian Sea stream which strikes the west coast in Kerala (southern tip of India), and the Bay of Bengal stream that strikes Assam and other northeastern states by 1 June.…”

Section: Introductionmentioning

confidence: 99%

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Simulation of the Indian summer monsoon onset-phase rainfall using a regional model

et al. 2015

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Abstract. This study examines the ability of the Advanced Research WRF (ARW) regional model to simulate Indian summer monsoon (ISM) rainfall climatology in different climate zones during the monsoon onset phase in the decade 2000-2009. The initial and boundary conditions for ARW are provided from the NCEP/NCAR Reanalysis Project (NNRP) global reanalysis. Seasonal onset-phase rainfall is compared with corresponding values from 0.25 • IMD (India Meteorological Department) rainfall and NNRP precipitation data over seven climate zones (perhumid, humid, dry/moist, subhumid, dry/moist, semiarid and arid) of India to see whether dynamical downscaling using a regional model yields advantages over just using large-scale model predictions. Results show that the model could simulate the onset phase in terms of progression and distribution of rainfall in most zones (except over the northeast) with good correlations and low error metrics. The observed mean onset dates and their variability over different zones are well reproduced by the regional model over most climate zones. It has been found that the ARW performed similarly to the reanalysis in most zones and improves the onset time by 1 to 3 days in zones 4 and 7, in which the NNRP shows a delayed onset compared to the actual IMD onset times. The variations in the onset-phase rainfall during the below-normal onset (June negative) and above-normal onset (June positive) phases are well simulated. The slight underestimation of onset-phase rainfall in the northeast zone could be due to failure in resolving the wide extent of topographic variations and the associated multiscale interactions in that zone. Spatial comparisons showed improvement of pentad rainfall in both space and quantity in ARW simulations over NNRP data, as evident from a wider eastward distribution of pentad rainfall over the Western Ghats, central and eastern India, as in IMD observations. While NNRP under-represented the high pentad rainfall over northeast, east and west coast areas, the ARW captured these regional features showing improvement upon NNRP reanalysis, which may be due to the high resolution (30 km) employed. The onset-phase rainfall characteristics during the contrasting ISM of 2003 and 2009 are well simulated in terms of the variations in the strength of low-level jet (LLJ) and outgoing long-wave radiation (OLR).

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“…It has been found from an inspection of weekly SST that there were no significant differences in its evolution two monsoons were of similar nature (Flatau et al, 2003). Nevertheless, the July rainfall shows a distinct contrast in the form of a dipole anomaly over India: a 'negative' rainfall anomaly over western India and a 'positive' anomaly over eastern India (Figure 9 (Figure 9(b)), which implies the dominance of these transients during July.…”

Section: Observed and Simulated Mean Rainfallmentioning

confidence: 99%

Simulation of Indian summer monsoon: sensitivity to cumulus parameterization in a GCM

Deb¹,

Upadhyaya²,

Sharma³

et al. 2006

Intl Journal of Climatology

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Abstract:Hindcasts for the Indian summer monsoons (ISMs) of 2002 and 2003 have been produced from a series of numerical simulations performed with a general circulation model using different cumulus parameterization schemes. Ten sets of ensemble simulations have been produced without using any vegetation scheme but by prescribing the monthly observed SST from the ECMWF (European Centre for Medium Range Weather Forecasts) analyses. For each ensemble, ten simulations have been realised with different initial conditions that are also prepared from the ECMWF data: five each from the April and May analyses of both the years. Stream function, velocity potential with divergent winds at 200 hPa, winds at 850 hPa and rainfall patterns with their anomalies have been analysed and interpreted. The large-scale upper and lower level circulation features are simulated satisfactorily. The spatial structure of predicted July monsoon rainfall over India shows a fair agreement with the GPCP (observed) pentad rainfall distribution. The variability associated with all-India June-July simulated rainfall time series matches reasonably well with the observations in 2003, but the model fails to simulate the observed variability in July 2002. Further evaluation of the model-produced precipitation in seasonal simulations is done with the help of empirical orthogonal functions (EOFs) of the GPCP rainfall over India. Since the first four EOFs explain a significant part of the total variance of the observed rainfall, the simulated precipitation is projected on to these modes. Thus, the differences in simulated and observed rainfall fields manifest in the time series of their expansion coefficients, which are utilised for inter-comparison/evaluation of model simulations.

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Delayed onset of the 2002 Indian monsoon

Cited by 53 publications

References 10 publications

The Variability of the Asian Summer Monsoon

The Variability of the Asian Summer Monsoon

Simulation of the Indian summer monsoon onset-phase rainfall using a regional model

Simulation of Indian summer monsoon: sensitivity to cumulus parameterization in a GCM

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