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Northeast monsoon over India: variability and prediction

Rajeevan, M and Unnikrishnan, CK and Bhate, Jyoti and Kumar, Niranjan K and Sreekala, PP (2012) Northeast monsoon over India: variability and prediction. In: METEOROLOGICAL APPLICATIONS, 19 (2, SI). pp. 226-236.

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Official URL: http://dx.doi.org/10.1002/met.1322

Abstract

South peninsular India experiences a large portion of the annual rainfall during the northeast monsoon season (October to December). In this study, the facets of diurnal, intra-seasonal and inter-annual variability of the northeast monsoon rainfall (the NEMR) over India have been examined. The analysis of satellite derived hourly rainfall reveals that there are distinct features of diurnal variation over the land and oceans during the season. Over the land, rainfall peaks during the late afternoon/evening, while over the oceans an early morning peak is observed. The harmonic analysis of hourly data reveals that the amplitude and variance are the largest over south peninsular India. The NEMR also exhibits significant intra-seasonal variability on a 20-40 day time scale. Analysis also shows significant northward propagation of the maximum cloud zone from south of equator to the south peninsula during the season. The NEMR exhibits large inter-annual variability with the co-efficient of variation (CV) of 25%. The positive phases of ENSO and the Indian Ocean Dipole (IOD) are conducive for normal to above normal rainfall activity during the northeast monsoon. There are multi-decadal variations in the statistical relationship between ENSO and the NEMR. During the period 2001-2010 the statistical relationship between ENSO and the NEMR has significantly weakened. The analysis of seasonal rainfall hindcasts for the period 1960-2005 produced by the state-of-the-art coupled climate models, ENSEMBLES, reveals that the coupled models have very poor skill in predicting the inter-annual variability of the NEMR. This is mainly due to the inability of the ENSEMBLES models to simulate the positive relationship between ENSO and the NEMR correctly. Copyright (C) 2012 Royal Meteorological Society

Item Type: Journal Article
Additional Information: Copyright for this article belongs to John Wiley & Sons
Keywords: northeast monsoon;interannual variability;seasonal forecasts;diurnal variation;intraseasonal variation
Department/Centre: Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited: 05 Jul 2012 07:54
Last Modified: 06 Jul 2012 09:50
URI: http://eprints.iisc.ernet.in/id/eprint/44765

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