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The spatio-temporal structures and role of low- and high-frequency intraseasonal modes in Indian Summer monsoon rainfall observed in TRMM data

Karmakar, Nirupam and Chakraborty, Arindam and Nanjundiah, Ravi S (2016) The spatio-temporal structures and role of low- and high-frequency intraseasonal modes in Indian Summer monsoon rainfall observed in TRMM data. In: Conference on Remote Sensing and Modeling of the Atmosphere, Oceans, and Interactions VI, APR 04-07, 2016, Indian Soc Remote Sensing, New Delhi, INDIA.

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Official URL: http://dx.doi.org/10.1117/12.2228030

Abstract

This study uses precipitation estimates from the Tropical Rainfall Measuring Mission to estimate the intensity and examine the spatiotemporal patterns in the modes found in intraseasonal timescale over the Indian monsoon region during boreal summer. Here, using multichannel singular spectrum analysis, two dominant modes of oscillations are found in the intraseasonal timescale with periodicity of 10-20-days and 20-60-days, respectively. 20-60-days mode shows northward propagation from the equatorial Indian Ocean linked with the eastward propagating modes of convective systems over the tropics. 10-20-days mode shows very complex structure with a northwestward propagating anomaly pattern emanating from the Indonesian coast moving towards central India. This pattern is found to have a possible interaction with a structure emerging from higher latitudes propagating southeastwards. The two intraseasonal modes contribute comparable amount to the total rainfall variability. The intensity of the 20-60-days (10-20-days) mode show significantly strong inverse (direct) relationship with all India June-September rainfall and both the modes exhibit profound variability in their intensity in interannual scale. This study also establishes that the probability of getting good amount of rainfall (no rainfall) over central India increases significantly if the two intraseasonal modes exhibit positive (negative) anomalies over the region. Relation between the ISO intensities and sea surface temperature is also discussed. This study points towards the fact that the knowledge of ISO phases can increase the skill in the probabilistic forecasting of rainfall over India.

Item Type: Conference Proceedings
Additional Information: Copy right for this article belongs to the SPIE-INT SOC OPTICAL ENGINEERING, 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA
Department/Centre: Division of Mechanical Sciences > Divecha Centre for Climate Change
Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Depositing User: Id for Latest eprints
Date Deposited: 22 Oct 2016 09:37
Last Modified: 03 Nov 2016 07:34
URI: http://eprints.iisc.ac.in/id/eprint/55055

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