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Energetics of lower tropospheric planetary waves over mid latitudes: Precursor for Indian summer monsoon

Bawiskar, SM and Chipade, MD and Puranik, PV and Bhide, UV (2005) Energetics of lower tropospheric planetary waves over mid latitudes: Precursor for Indian summer monsoon. Journal of Earth System Science, 114 (5). pp. 557-564.

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Abstract

Based on NCEP/NCAR reanalysis data, kinetic energy and momentum transport of waves 0 to 10 at 850 hPa level are computed from monthly mean zonal (u) and meridional (v) components of wind from equator to 90°N. Fourier technique is used to resolve the wind field into a spectrum of waves: Correlation analysis between All India Seasonal Monsoon Rainfall (AISMR) and energetics of the waves indicates that effective kinetic energy of waves 1, 3 and 4 around 37.5°N in February has significant correlation (99.9) with the subsequent AISMR. A simple linear regression equation between the effective kinetic energy of these three waves and AISMR is developed. Out of 47 years' (1958-2004) data, 32 years (1958-1989) are utilized for developing the regression model and the remaining 15 years (1990-2004) are considered for its verification. Predicted AISMR is in close agreement with observed AISMR. The regression equation based on the dynamics of the planetary waves is thus useful for Long Range Forecasting (LRF) of AISMR. Apart from the regression equation, the study provides qualitative predictors. The scatter diagram between AISMR and effective kinetic energy of waves 1, 3 and 4 around 37.5°N indicates that if the kinetic energy is more (less) than 5 m2s-2, the subsequent monsoon will be good (weak). Stream function fields indicate that high latitude trough axis along 40°E (70°E) leads to a good (weak) monsoon over India.

Item Type: Article
Additional Information: Copyright of this article belongs to Indian Academy of Science
Uncontrolled Keywords: atmospheric wave; kinetic energy; momentum transfer; monsoon; troposphere
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 18 Apr 2015 06:29
Last Modified: 18 Apr 2015 06:29
URI: http://moeseprints.incois.gov.in/id/eprint/1400

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