Objective Calculations of Divergence, Vertical Velocity and Vorticity

1949 ◽  
Vol 30 (2) ◽  
pp. 45-49 ◽  
Author(s):  
John C. Bellamy
Keyword(s):  
Vertical Velocity ◽  
Wind Field

Methods of calculating horizontal divergence, vertical velocity and vorticity directly from wind observations without analyzing the wind field are presented. The appropriate formulae for these quantities in terms of the finite areas or volumes determined by the observation points are derived. Convenient nomographs and tabular forms for their calculation are described and illustrated.

Atmospheric Turbulence Encountered by High-Speed Ground Transport Vehicles

1977 ◽  
Vol 19 (5) ◽  
pp. 227-235 ◽  
Author(s):  
L. A. Balzer
Keyword(s):  
Atmospheric Turbulence ◽  
Vertical Velocity ◽  
Wind Field ◽  
High Speed ◽  
Statistical Properties ◽  
Arbitrary Orientation ◽  
Turbulent Wind ◽  
Transport Vehicle ◽  
Turbulent Wind Field

The structure of atmospheric turbulence near the ground is reviewed and the statistical properties of the longitudinal, lateral and vertical velocity components of the wind presented. The statistical properties of the turbulence encountered by a high-speed ground transport vehicle travelling through a turbulent wind field of arbitrary orientation are derived. Next, the statistical properties of the atmospheric forces acting on the vehicle are determined and a method of taking account of finite vehicle length is presented. The resulting formulae are applied to a typical tracked hovercraft vehicle.

scholarly journals Estimation of divergent wind from OLR data for use in objective analysis over the Indian region

MAUSAM ◽  
2021 ◽  
Vol 44 (1) ◽  
pp. 77-84
Author(s):  
P. L. KULKARNI ◽  
D. R. TALWALKAR ◽  
S. NAIR
Keyword(s):  
Vertical Velocity ◽  
Wind Field ◽  
Empirical Relation ◽  
Initial Guess ◽  
Indian Region ◽  
Divergent Part ◽  
Free Region ◽  
Synoptic Conditions ◽  
Cloudy Region ◽  
Cloud Top Temperature

A scheme is formulated for the use of OLR data in the estimation of vertical velocity; divergence and then the divergent part of the wind over Indian region. In this scheme, ascending motion over cloudy region is estimated from an empirical relation between the cloud top temperature and descending motion over cloud-free region is estimated from the thermodynamic energy equation and both are blended. From this blended vertical velocity field, aivergence, velocity potential and divergent winds at all standard levels from 4 to 8 July 1979 at 00 UTC are computed. These fields are compared with satellite cloud pictures, rainfall etc and they are found to be realistic in depicting the synoptic conditions. Total wind is computed as the sum of the estimated divergent component and rotational component computed from observed wind field. For assessment of the scheme, this total wind field at 850 hPa is used as initial. guess field in univariate optimum interpolation scheme and analyses were made for the period 4 to 8 July 1979. Results show that scheme is able to produce realistic analyses which included divergent part of the wind.

Three-Dimensional Structure and Evolution of the Vertical Velocity and Divergence Fields in the MJO

2014 ◽  
Vol 71 (12) ◽  
pp. 4661-4681 ◽  
Author(s):  
Ángel F. Adames ◽  
John M. Wallace
Keyword(s):  
Velocity Field ◽  
Vertical Velocity ◽  
Wind Field ◽  
Three Dimensional ◽  
Warm Pool ◽  
Companion Paper ◽  
Dimensional Structure ◽  
Meridional Plane ◽  
Planetary Scale ◽  
Vertical Velocity Profile

Abstract The features in the planetary-scale wind field that shape the MJO-related vertical velocity field are examined using the linear analysis protocol based on the daily global velocity potential field described in a companion paper, augmented by a compositing procedure that yields a more robust and concise description of the prevalent patterns over the Indo-Pacific warm pool sector (60°E–180°). The analysis elucidates the structural elements of the planetary-scale wind field that give rise to the characteristic “swallowtail” shape of the region of enhanced rainfall and the “bottom up” evolution of the vertical velocity profile from one with a shallow peak on the eastern end of the region of enhanced rainfall to one with an elevated peak on the western end. These distinctive features of the vertical velocity field in the MJO reflect the juxtaposition of deep overturning circulation cells in the equatorial plane and much shallower frictionally driven cells in the meridional plane to the east and west of the regions of enhanced rainfall. The zonal overturning circulations determine the pattern of ∂u/∂x and the meridional overturning circulations determine the pattern of ∂υ/∂y in the divergence profiles. These features are at least qualitatively well represented by the Matsuno–Gill solution for the planetary wave response to a stationary equatorial heat source–sink dipole.

Combining SAR interferometry and the equation of continuity to estimate the three-dimensional glacier surface-velocity vector

1999 ◽  
Vol 45 (151) ◽  
pp. 533-538 ◽  
Author(s):  
Niels Reeh ◽  
Søren Nørvang Madsen ◽  
Johan Jakob Mohr
Keyword(s):  
Steady State ◽  
Mass Balance ◽  
Vertical Velocity ◽  
Velocity Vector ◽  
Thickness Distribution ◽  
Vertical Surface ◽  
Horizontal Velocity ◽  
Sar Interferometry ◽  
Surface Velocity ◽  
Ice Thickness

AbstractUntil now, an assumption of surface-parallel glacier flow has been used to express the vertical velocity component in terms of the horizontal velocity vector, permitting all three velocity components to be determined from synthetic aperture radar interferometry. We discuss this assumption, which neglects the influence of the local mass balance and a possible contribution to the vertical velocity arising if the glacier is not in steady state. We find that the mass-balance contribution to the vertical surface velocity is not always negligible as compared to the surface-slope contribution. Moreover, the vertical velocity contribution arising if the ice sheet is not in steady state can be significant. We apply the principle of mass conservation to derive an equation relating the vertical surface velocity to the horizontal velocity vector. This equation, valid for both steady-state and non-steady-state conditions, depends on the ice-thickness distribution. Replacing the surface-parallel-flow assumption with a correct relationship between the surface velocity components requires knowledge of additional quantities such as surface mass balance or ice thickness.

scholarly journals Vertical Structure of Spiral Shocks in a Corrugated Galactic Disc

1983 ◽  
Vol 100 ◽  
pp. 145-146
Author(s):  
A. H. Nelson ◽  
T. Matsuda ◽  
T. Johns
Keyword(s):  
Density Profile ◽  
Vertical Velocity ◽  
Gas Flow ◽  
Vertical Structure ◽  
Vertical Motion ◽  
Shock Structure ◽  
Galactic Disc ◽  
Gaussian Density ◽  
Abundant Evidence ◽  
Steady Shock

Numerical calculations of spiral shocks in the gas discs of galaxies (1,2,3) usually assume that the disc is flat, i.e. the gas motion is purely horizontal. However there is abundant evidence that the discs of galaxies are warped and corrugated (4,5,6) and it is therefore of interest to consider the effect of the consequent vertical motion on the structure of spiral shocks. If one uses the tightly wound spiral approximation to calculate the gas flow in a vertical cut around a circular orbit (i.e the ⊝ -z plane, see Nelson & Matsuda (7) for details), then for a gas disc with Gaussian density profile in the z-direction and initially zero vertical velocity a doubly periodic spiral potential modulation produces the steady shock structure shown in Fig. 1. The shock structure is independent of z, and only a very small vertical motion appears with anti-symmetry about the mid-plane.

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