scholarly journals A model study of the 30-50 day oscillation In the tropical atmosphere

MAUSAM ◽  
2021 ◽  
Vol 42 (3) ◽  
pp. 241-248
Author(s):  
S. V. KASTURE ◽  
V. SATYAN ◽  
R.N. KESHAVAMURTY
Keyword(s):  
Composite System ◽  
Spectral Model ◽  
Wave Number ◽  
Tropical Atmosphere ◽  
Global Spectral Model ◽  
Availability Factor ◽  
Moisture Availability ◽  
Model Study ◽  
Model Response ◽  
The Waves

Using a global spectral model with wave-CISK formulation we have generated an eastward de which. Resembles the observed 30-50 day mode. This has a scale of global wave number one and two years structure in the vertical. It has the structure of a composite of Kelvin and Rossby waves. This composite  system moves eastwards. We have also studied a linear two-level analytical model to understand the nonlinear spectral model response. In the linear as well as in the nonlinear spectral model, as we Increase the moisture availability factor the speeds of the waves decrease. In the linear model this speed is found to be independent of drag for all types of waves. In the nonlinear spectral model for a given drag there is a critical value of the moisture availability factor for which the wave becomes stationary and beyond which even shows westward propagation. Thus both moisture availability and nonlinearity appear to contribute to the slow eastward speed of the equatorial 30-50 day mode.  

Longitudinal Waves in a Submerged Cylindrical Rod 1

2010 ◽  
Vol 78 (2) ◽  
Author(s):  
G. Iosilevskii
Keyword(s):  
Boundary Layer ◽  
Wave Number ◽  
Analytical Relation ◽  
Velocity Of Sound ◽  
Longitudinal Displacement ◽  
Wave Propagation Velocity ◽  
Longitudinal Waves ◽  
Short Waves ◽  
The Waves ◽  
Surrounding Fluid

This study is concerned with longitudinal displacement waves propagating in an elastic cylindrical rod submerged in a viscous fluid. Provided that the wave propagation velocity in the rod is small compared with the velocity of sound in the surrounding fluid and the wavelength is large compared with the thickness of the boundary layer around the rod, an analytical relation is obtained between the wave number and the frequency. The presence of the fluid makes the waves disperse—the short waves become faster than the long ones.

A Global Spectral Model for Simulation of the General Circulation

1978 ◽  
Vol 35 (9) ◽  
pp. 1557-1583 ◽  
Author(s):  
Bryant J. McAvaney ◽  
William Bourke ◽  
Kamal Puri
Keyword(s):  
General Circulation ◽  
Spectral Model ◽  
Global Spectral Model

scholarly journals Michio Yanai and Tropical Waves

2016 ◽  
Vol 56 ◽  
pp. 3.1-3.21 ◽  
Author(s):  
Yukari N. Takayabu ◽  
George N. Kiladis ◽  
Victor Magaña
Keyword(s):  
Fundamental Problem ◽  
Tropical Meteorology ◽  
Current Understanding ◽  
Tropical Atmosphere ◽  
Design Phase ◽  
Wave Disturbances ◽  
Cloud Clusters ◽  
Tropical Waves ◽  
Tropical Wave ◽  
The Waves

Abstract Insights by Professor Michio Yanai on tropical waves, which have been vital ingredients for progress in tropical meteorology over the last half-century, are recollected. This study revisits various aspects of research on tropical waves over the last five decades to examine, in Yanai’s words, “the nature of ‘A-scale’ tropical wave disturbances and the interaction of the waves and the ‘B-scale’ phenomena (cloud clusters),” the fundamental problem posed by Yanai at the design phase of the GARP Atlantic Tropical Experiment (GATE) in 1971. The various contributions of Michio Yanai to the current understanding of the dynamics of the tropical atmosphere are briefly reviewed to show how his work has led to several current theories in this field.

DISPERSION RELATIONS FOR COLD PLASMA AROUND THE HORIZON OF SCHWARZSCHILD–DE SITTER BLACK HOLE

2010 ◽  
Vol 19 (02) ◽  
pp. 113-135
Author(s):  
M. KHAYRUL HASAN
Keyword(s):  
Black Hole ◽  
Cold Plasma ◽  
Wave Number ◽  
Linear Perturbation ◽  
De Sitter ◽  
Rindler Coordinates ◽  
General Relativistic ◽  
Phase And Group Velocities ◽  
The Waves ◽  
Complex Dispersion

In this paper, we investigate the wave properties of cold plasma in the vicinity of Schawarzchild–de Sitter black hole horizon using 3 + 1 formalism. The general relativistic magnetohydrodynamical equations are formulated for this space–time with the use of Rindler coordinates. We consider both the rotating and nonrotating surroundings with magnetized and nonmagnetized plasmas. Linear perturbation and Fourier analysis techniques are applied by introducing simple harmonic waves. We derive complex dispersion relation from the determinant of Fourier analyzed equations for each case which provides real and complex values of the wave number. From the wave number we determine the phase and group velocities, the refractive index etc., which are used to discuss the characteristics of the waves around the event horizon.

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