Some effects of rotation rate on planetary-scale wave flows

1993 ◽  
Vol 10 (3) ◽  
pp. 296-306
Author(s):  
Li Guoqing ◽  
Robin Kung ◽  
Richard L. Pfeffer
Keyword(s):  
Rotation Rate ◽  
Planetary Scale ◽  
Effects Of Rotation ◽  
Wave Flows

Some effects of rotation rate on planetary ? scale wave flows

1996 ◽  
Vol 55 (1-4) ◽  
pp. 199-210
Author(s):  
G. -Q. Li ◽  
R. Kung ◽  
R. L. Pfeffer
Keyword(s):  
Rotation Rate ◽  
Planetary Scale ◽  
Effects Of Rotation ◽  
Wave Flows

Rotation

2013 ◽  
Author(s):  
Gary A. Glatzmaier
Keyword(s):  
Spherical Shell ◽  
Accretion Disk ◽  
Gravity Waves ◽  
Equatorial Plane ◽  
Rotation Rate ◽  
Rate Of Change ◽  
Cylindrical Annulus ◽  
Planetary Rotation ◽  
Effects Of Rotation ◽  
Rotating Star

This chapter examines the effects of rotation on convection and gravity waves. Flows in the atmospheres, oceans, and liquid cores of terrestrial planets are dominated by the Coriolis forces, as are the interiors of giant planets and stars. The sum of gravitational and centrifugal forces can go to zero at the top boundary of a rapidly rotating star or accretion disk. The time rate of change of the planetary rotation rate gives rise to Poincaré forces. The chapter first considers Coriolis, centrifugal, and Poincaré forces before explaining the modifications needed to add these effects of rotation to previous models of convection and gravity waves in 2D cartesian box and cylindrical annulus geometries, both of which now lie within a rotating equatorial plane. It also describes 2.5D rotating models and 3D spherical-shell magnetohydrodynamic dynamo models.

Effects of rotation rate, mixing angle, and cohesion in two continuous powder mixers—A statistical approach

2009 ◽  
Vol 194 (3) ◽  
pp. 217-227 ◽  
Author(s):  
Patricia M. Portillo ◽  
Marianthi G. Ierapetritou ◽  
Fernando J. Muzzio
Keyword(s):  
Rotation Rate ◽  
Statistical Approach ◽  
Mixing Angle ◽  
Effects Of Rotation

scholarly journals The rotation of α Oph investigated using polarimetry

2020 ◽  
Vol 494 (2) ◽  
pp. 2254-2267 ◽  
Author(s):  
Jeremy Bailey ◽  
Daniel V Cotton ◽  
Ian D Howarth ◽  
Fiona Lewis ◽  
Lucyna Kedziora-Chudczer
Keyword(s):  
Rotation Rate ◽  
Rotation Axis ◽  
Wavelength Dependence ◽  
Position Angle ◽  
Type Star ◽  
Sequence Evolution ◽  
Effects Of Rotation ◽  
Polar Radius ◽  
Rotating Star ◽  
Polarization Models

ABSTRACT Recently we have demonstrated that high-precision polarization observations can detect the polarization resulting from the rotational distortion of a rapidly rotating B-type star. Here, we investigate the extension of this approach to an A-type star. Linear-polarization observations of α Oph (A5IV) have been obtained over wavelengths from 400 to 750 nm. They show the wavelength dependence expected for a rapidly rotating star combined with a contribution from interstellar polarization. We model the observations by fitting rotating-star polarization models and adding additional constraints including a measured vesin i. However, we cannot fully separate the effects of rotation rate and inclination, leaving a range of possible solutions. We determine a rotation rate (ω = Ω/Ωc) between 0.83 and 0.98 and an axial inclination i > 60°. The rotation-axis position angle is found to be 142 ± 4°, differing by 16° from a value obtained by interferometry. This might be due to precession of the rotation axis due to interaction with the binary companion. Other parameters resulting from the analysis include a polar temperature Tp = 8725 ± 175 K, polar gravity log gp = 3.93 ± 0.08 (dex cgs), and polar radius Rp = 2.52 ± 0.06 R⊙. Comparison with rotating-star evolutionary models indicates that α Oph is in the later half of its main-sequence evolution and must have had an initial ω of 0.8 or greater. The interstellar polarization has a maximum value at a wavelength (λmax) of 440 ± 110 nm, consistent with values found for other nearby stars.

scholarly journals Effects of Rotation on the Multiscale Organization of Convection in a Global 2D Cloud-Resolving Model

2019 ◽  
Vol 76 (11) ◽  
pp. 3669-3696
Author(s):  
Qiu Yang ◽  
Andrew J. Majda ◽  
Noah D. Brenowitz
Keyword(s):  
Surface Fluxes ◽  
Vertical Shear ◽  
Spatiotemporal Variability ◽  
Asymptotic Model ◽  
Synoptic Scale ◽  
Convective Systems ◽  
Planetary Scale ◽  
Zonal Winds ◽  
Budget Analysis ◽  
Effects Of Rotation

Abstract Atmospheric convection exhibits distinct spatiotemporal variability at different latitudes. A good understanding of the effects of rotation on the multiscale organization of convection from the mesoscale to synoptic scale to planetary scale is still lacking. Here cloud-resolving simulations with fixed surface fluxes and radiative cooling are implemented with constant rotation in a two-dimensional (2D) planetary domain to simulate multiscale organization of convection from the tropics to midlatitudes. All scenarios are divided into three rotation regimes (weak, order-one, and strong) to represent the idealized ITCZ region (0°–6°N), the Indian monsoon region (6°–20°N), and the midlatitude region (20°–45°N), respectively. In each rotation regime, a multiscale asymptotic model is derived systematically and used as a diagnostic framework for energy budget analysis. The results show that planetary-scale organization of convection only arises in the weak rotation regime, while synoptic-scale organization dominates (vanishes) in the order-one (strong) rotation regime. The depletion of planetary-scale organization of convection as the magnitude of rotation increases is attributed to the reduced planetary kinetic energy of zonal winds, mainly due to the decreasing acceleration effect by eddy zonal momentum transfer from mesoscale convective systems (MCSs) and the increasing deceleration effect by the Coriolis force. Similarly, the maintenance of synoptic-scale organization is related to the acceleration effect by MCSs. Such decreasing acceleration effects by MCSs on both planetary and synoptic scales are further attributed to less favorable conditions for convection provided by weaker background vertical shear of the zonal winds, resulting from the increasing magnitude of rotation.

Analysis of planetary cloud images considering local rotation

2021 ◽  
Author(s):  
Keishiro Muto ◽  
Takeshi Imamura
Keyword(s):  
Rotation Rate ◽  
Large Scale ◽  
Correlation Method ◽  
Small Scale ◽  
Body Rotation ◽  
Clockwise Rotation ◽  
Solid Body Rotation ◽  
Planetary Scale ◽  
Parallel Movement ◽  
Cloud Tracking

<p>Cloud tracking has been used to measure motions of planetary atmospheres remotely without direct observations. Cloud tracking is a method to track the movements of cloud parcels using temporally-continuous cloud images to obtain cloud motion vectors. Since it is considered in most of the cases that clouds move at the same speed and the same direction as the surrounding atmosphere, the wind direction and wind velocity can be obtained by tracking the movement of clouds. This method has been applied to the atmospheres of the planets, such as Venus and Jupiter, where direct observation is difficult as well as that of the Earth's atmosphere.</p> <p>In the cloud tracking methods developed so far, only the parallel movement of the characteristic pattern is assumed, and the rotation of the pattern is not directly measured. Here we developed a new algorithm to track the parallel movement and the rotation of cloud patterns using the rotation invariant phase-only correlation method. In this method, the tracking region is Fourier-transformed before applying the phase correlation method for measuring parallel movement, and logarithmic polar coordinate conversion is performed to the amplitude spectra so that the rotation and enlargement/reduction motions can be obtained as parallel movements. With this method, not only the parallel movement but also the rotational movement of the characteristic pattern can be detected at the same time.</p> <p>We first applied the newly-developed method to simulated image pairs. The rotation rate of the cloud pattern and the vorticity derived from the velocity field were compared in three velocity patterns: solid body rotation, irrotational vortex, and sinusoidal velocity field in the latitude and longitude directions. As a result, in the case of a solid body rotation, the wind speed field and the rotation angle were determined correctly. Large-scale rotations can be measured more accurately by the new method than by the calculation of vorticity from the cloud-tracked velocity. When the scale of the velocity structure is decreased, the number of missing cloud tracking vectors increases, and thus the spatial pattern of the vorticity becomes difficult to obtain. Even in such cases, the spatial pattern of the rotation rate can be relatively well retrieved although its amplitude is underestimated.</p> <p>The new method was applied to Jupiter and Venus images based on the results above. For Jupiter, many small eddies were found to be distributed in the equatorial region. The spatial scales and the strengths of the eddies resemble those seen in numerical simulations. The observed vortex chains can contribute to the formation of Jupiter's equatorial jet. For Venus, though small-scale eddies are less prominent, a planetary-scale distribution of the rotation rate with a north-south reflection symmetry was seen, such that anti-clockwise rotation occurs in the northern hemisphere and clockwise rotation in the southern hemisphere. Since the large-scale rotation pattern is consistent with the latitudinal shear of the mean zonal wind, the result means that the rotation of small-scale clouds is caused by the large-scale wind. This result suggests that the small-scale streaky features at mid-latitudes, whose origin is poorly understood, are created by the deformation of clouds by large-scale winds.</p> <p>The newly-developed method can extract smaller scale eddies than those observed in the previous studies; the method has enabled investigation of the interaction between different scales in a wider wavelength range. The method would also enable studies of mesoscale weather systems such as deep convection and also studies of upward energy cascade from small-scale convective storms to planetary scale motions in planetary atmospheres.</p>

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