Observational evidence of mixed rossby gravity waves at the central equatorial Indian Ocean

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dc.contributor.author Muraleedharan, P.M.
dc.contributor.author PrasannaKumar, S.
dc.contributor.author Mohankumar, K.
dc.contributor.author Sijikumar, S.
dc.contributor.author Sivakumar, K.U.
dc.contributor.author Mathew, T.
dc.date.accessioned 2015-10-26T08:39:11Z
dc.date.available 2015-10-26T08:39:11Z
dc.date.issued 2015
dc.identifier.citation Meteorology and Atmospheric Physics, vol.127(4); 2015; 407-417
dc.identifier.uri http://drs.nio.org/drs/handle/2264/4807
dc.description.abstract Six-hourly soundings (GPS sonde) were carried out at the central equatorial Indian Ocean (80º–83ºE) during 25th September–10th October 2011 under the CINDY2011 (Cooperative Indian Ocean Experiment on Intra-seasonal variability in Year 2011) field campaign. One-degree interval soundings were also taken along a meridional section at 83ºE from 5ºN to 5ºS during 12–20 October 2011 to supplement the time series data. Relative humidity (RH) and meridional wind component exhibit downward propagation of air mass in bands of high and low RH associated with northerly and southerly winds, respectively. Low (20–100 day) and high (2–10 day) frequency band pass filtered OLR data (NOAA-interpolated OLR) revealed the presence of Madden and Julian Oscillation (MJO) with 20- to 40-day periodicity, and weak Mixed Rossby Gravity (MRG) waves with 4- to 5-day periodicity. Eastward (westward) propagating MJO (MRG wave) with wave numbers 3–4 (4–5), amplitudes of anomaly 1.1–1.2 Wm<sup>-2</sup> (1.8 Wm<sup>-2</sup>) were observed. The asymmetric bifurcation of warm surface water by the subsurface cold water off Sumatra generate asymmetric convective regimes in the vicinity of the equator probably triggered convection with periodicity similar to MRG waves. The intermittent surface convection associated is believed to be responsible for the ascending moisture to the middle troposphere prior to the initiation of MJO. The moisture pumped to the middle troposphere makes the layer convectively more unstable leading to the state of deep convection, a situation conducive for the MJO initiation processes
dc.language.iso en
dc.publisher Springer
dc.rights An edited version of this paper was published by Springer. This paper is for R & D purpose and Copyright [2015] Springer.
dc.title Observational evidence of mixed rossby gravity waves at the central equatorial Indian Ocean
dc.type Journal Article

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