scholarly journals Isentropic Pressure and Mountain Torques

2009 ◽  
Vol 137 (9) ◽  
pp. 3047-3054 ◽  
Author(s):  
Joseph Egger ◽  
Klaus-Peter Hoinka
Keyword(s):  
Angular Momentum ◽  
Potential Temperature ◽  
Polar Caps ◽  
The Earth ◽  
Momentum Budget

Abstract The relation of pressure torques and mountain torques is investigated on the basis of observations for the polar caps, two midlatitude and two subtropical belts, and a tropical belt by evaluating the lagged covariances of these torques for various isentropic surfaces. It is only in the polar domains and the northern midlatitude belts that the transfer of angular momentum to and from the earth at the mountains is associated with pressure torques acting in the same sense. The situation is more complicated in all other belts. The covariances decline with increasing potential temperature (height). The role of both torques in the angular momentum budget of a belt is discussed.

Axial Atmospheric Angular Momentum Budget at Diurnal and Subdiurnal Periodicities

2008 ◽  
Vol 65 (1) ◽  
pp. 156-171 ◽  
Author(s):  
François Lott ◽  
Olivier de Viron ◽  
Pedro Viterbo ◽  
François Vial
Keyword(s):  
Boundary Layer ◽  
Angular Momentum ◽  
Surface Pressure ◽  
Vertical Direction ◽  
Zonal Flow ◽  
Atmospheric Angular Momentum ◽  
Model Driven ◽  
The Earth ◽  
Momentum Budget ◽  
Diurnal Period

Abstract The diurnal and subdiurnal variations of the mass and wind terms of the axial atmospheric angular momentum (AAM) are explored using a 1-yr integration of the Laboratoire de Météorologie Dynamique (LMDz) GCM, twelve 10-day ECMWF forecasts, and some ECMWF analysis products. In these datasets, the wind and mass AAMs present diurnal and semidiurnal oscillations for which tendencies far exceed the total torque. In the LMDz GCM, these diurnal and semidiurnal oscillations are associated with axisymmetric (s = 0) and barotropic circulation modes that resemble the second gravest (n = 2) eigensolution of Laplace’s tidal equations. This mode induces a Coriolis conversion from the wind AAM toward the mass AAM that far exceeds the total torque. At the semidiurnal period, this mode dominates the axisymmetric and barotropic circulation. At the diurnal period, this n = 2 mode is also present, but the barotropic circulation also presents a mode resembling the first gravest n = 1 eigensolution of the tidal equations. This last mode does not produce anomalies in the mass and wind AAMs. A shallow-water axisymmetric model driven by zonal mean zonal forces, for which the vertical integral equals the zonal mean zonal stresses issued from the GCM, is then used to interpret these results. This model reproduces well the semidiurnal oscillations in mass and wind AAM, and the semidiurnal mode resembling the n = 2 eigensolution that produces them, when the forcing is distributed barotropically in the vertical direction. This model also reproduces diurnal modes resembling the n = 1 and n = 2 eigensolutions when the forcings are distributed more baroclinically. Among the dynamical forcings that produce these modes of motion, it is found that the mountain forcing and the divergence of the AAM flux are equally important and are more efficient than the boundary layer friction. In geodesy, the large but opposite signals in the mass and wind AAM due to the n = 2 modes can lead to large errors in the evaluation of the AAM budget. The n = 2 responses in surface pressure can affect the earth ellipcity, and the n = 1 diurnal response can affect the geocenter position. For the surface pressure tide, the results suggest that the dynamical forcings of the zonal-mean zonal flow are a potential cause for its s = 0 component.

The Effect of Internally Generated Inner-Core Asymmetries on Tropical Cyclone Potential Intensity*

2007 ◽  
Vol 64 (4) ◽  
pp. 1165-1188 ◽  
Author(s):  
Bo Yang ◽  
Yuqing Wang ◽  
Bin Wang
Keyword(s):  
Angular Momentum ◽  
Tropical Cyclone ◽  
Potential Vorticity ◽  
Inner Core ◽  
Potential Temperature ◽  
Convective Heating ◽  
Internal Dynamic ◽  
Budget Analysis ◽  
Momentum Budget ◽  
Cooling Effects

Abstract In a quiescent environment on an f plane, the internal dynamic processes of a tropical cyclone (TC) can generate axially asymmetric circulations (asymmetries) in its inner-core region. The present study investigates how these inner-core asymmetries affect TC intensity. For this purpose, a three-dimensional (3D) TC model and its axisymmetric (2D) version were used. Both have identical model vertical structure and use the same set of parameters and the same initial conditions. The differences between the two model runs are considered to be due to mainly the effects of the TC asymmetries. The results show that the presence of asymmetries in the 3D run reduces the TC final intensity by about 15% compared with the 2D run, suggesting that the TC asymmetry is a limiting factor to the potential intensity (PI). In the 2D run without asymmetries, the convective heating in the eyewall generates an annular tower of high potential vorticity (PV) with relatively low PV in the eye. The eyewall tilts outward with height significantly. Underneath the tilted eyewall the downdrafts induced by evaporation of rain and melting of snow and graupel make the subcloud-layer inflow dry and cool, which lowers the boundary layer equivalent potential temperature (θe), thus increasing the entropy difference between the air and sea in the vicinity of the radius of maximum wind (RMW). The increased air–sea entropy deficit leads to more energy input into TC from the underlying ocean and thus a greater final intensity. On the other hand, in the 3D run, the model-resolved asymmetric eddies, which are characterized by the vortex Rossby waves in the mid-lower troposphere, play important roles in modifying the symmetric structure of the TC. Potential vorticity and θe budgets indicate that significant inward PV mixing from the eyewall into the eye results in a less-tilted eyewall, which in turn limits the drying and cooling effects of downdrafts in the subcloud layer and reduces the air–sea entropy deficit under the eyewall, thereby reducing the TC intensity. The angular momentum budget analysis shows that the asymmetric eddies tend to reduce the strength of the primary circulation in the vicinity of the RMW. This eddy contribution to the azimuthal mean angular momentum budget is larger than the parameterized horizontal diffusion contribution in the 3D run, suggesting an overall diffusive effect of the asymmetric eddies on the symmetric circulation.

Discrepancies in the Earth-atmosphere angular momentum budget

1990 ◽  
Vol 95 (B1) ◽  
pp. 265 ◽  
Author(s):  
Richard D. Rosen ◽  
David A. Salstein ◽  
Tamara M. Wood
Keyword(s):  
Angular Momentum ◽  
Earth Atmosphere ◽  
The Earth ◽  
Momentum Budget

Beyond the Social Determinants of Health

2020 ◽  
Vol 3 ◽  
pp. 1-11
Author(s):  
Laura Hall ◽  
Urpi Pine ◽  
Tanya Shute
Keyword(s):  
Labour Force ◽  
Methodological Approach ◽  
Active Role ◽  
Indigenous Women ◽  
Economic Activities ◽  
The Earth ◽  
The Social ◽  
Weather Changes ◽  
People First

Abstract This paper will reflect on key findings from a Summer 2017 initiative entitled The Role of Culture and Land-Based Healing in Addressing and Ending Violence against Indigenous Women and Two-Spirited People. The Indigenist and decolonizing methodological approach of this work ensured that all research was grounded in experiential and reciprocal ways of learning. Two major findings guide the next phase of this research, complicating the premise that traditional economic activities are healing for Indigenous women and Two-Spirit people. First, the complexities of the mainstream labour force were raised numerous times. Traditional economies are pressured in ongoing ways through exploitative labour practices. Secondly, participants emphasized the importance of attending to the responsibility of nurturing, enriching, and sustaining the wellbeing of soil, water, and original seeds in the process of creating renewal gardens as a healing endeavour. In other words, we have an active role to play in healing the environment and not merely using the environment to heal ourselves. Gardening as research and embodied knowledge was stressed by extreme weather changes including hail in June, 2018, which meant that participants spent as much time talking about the healing of the earth and her systems as the healing of Indigenous women in a context of ongoing colonialism.

“Eternal Bodies”: images of archangels in the upper parts of Nubian buildings

2020 ◽  
pp. 713-736
Author(s):  
Magdalena Łaptaś
Keyword(s):  
Near East ◽  
Structural Elements ◽  
Christian Art ◽  
The Earth ◽  
Cosmic Space

Images of archangels and angels, which were painted on the walls, in the upper parts of the buildings and, on their structural elements, were very popular in Christian Nubian painting as attested by the discoveries from Church SWN.BV on the citadel in Old Dongola. These images, which derive from pre-Christian art, depict the eternal nature of the archangels and angels. Presenting this group of representations, the author traces the origins of these images to highlight the role of these spiritual beings as intermediaries between God and humankind. As such, they move freely between the Heavens and the Earth, so the air and cosmic space are their natural surroundings. Moreover, archangels govern the forces of nature, the planets, and the seven skies. Therefore, their sanctuaries were located on hill summits, in the upper chapels, on structural elements of ecclesiastical buildings, etc. The Nubian tradition is therefore part of a broader Mediterranean tradition, the roots of which should be sought in the Near East.

The Role of the Earth Sciences in Fostering Global Equity & Stability

GSA Today ◽  
2003 ◽  
Vol 13 (3) ◽  
pp. 27
Author(s):  
W.G. Ernst ◽  
G. Heiken ◽  
Susan M. Landon ◽  
P. Patrick Leahy ◽  
Eldridge Moores
Keyword(s):  
Earth Sciences ◽  
The Earth

Kinematical evolution of Globular Clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 524-527
Author(s):  
Maria A. Tiongco ◽  
Enrico Vesperini ◽  
Anna Lisa Varri
Keyword(s):  
Angular Momentum ◽  
Structural Properties ◽  
Globular Clusters ◽  
Velocity Dispersion ◽  
Three Dimensional ◽  
Stellar Populations ◽  
Velocity Space ◽  
Fundamental Understanding

AbstractWe present several results of the study of the evolution of globular clusters’ internal kinematics, as driven by two-body relaxation and the interplay between internal angular momentum and the external Galactic tidal field. Via a large suite of N-body simulations, we explored the three-dimensional velocity space of tidally perturbed clusters, by characterizing their degree of velocity dispersion anisotropy and their rotational properties. These studies have shown that a cluster’s kinematical properties contain distinct imprints of the cluster’s initial structural properties, dynamical history, and tidal environment. Building on this fundamental understanding, we then studied the dynamics of multiple stellar populations in globular clusters, with attention to the largely unexplored role of angular momentum.

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