Formation of the Y Feature at the Venusian Cloud Top by Planetary‐Scale Waves and the Mean Circulation: Analysis of Venus Express VMC Images

2019 ◽  
Author(s):  
Y. Nara ◽  
T. Imamura ◽  
S. Murakami ◽  
T. Kouyama ◽  
K. Ogohara ◽  
...  
Keyword(s):  
Planetary Scale ◽  
The Mean ◽  
Venus Express ◽  
Mean Circulation

scholarly journals Simulated Relationships between Regional Temperatures and Large-Scale Circulation: 125 kyr BP (Eemian) and the Preindustrial Period

2005 ◽  
Vol 18 (19) ◽  
pp. 4032-4045 ◽  
Author(s):  
Nikolaus Groll ◽  
Martin Widmann ◽  
Julie M. Jones ◽  
Frank Kaspar ◽  
Stephan J. Lorenz
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Temperature Sensitive ◽  
Proxy Data ◽  
Large Scale Circulation ◽  
The North ◽  
Temperature Signal ◽  
Northern Winter ◽  
The Mean ◽  
Mean Circulation

Abstract To investigate relationships between large-scale circulation and regional-scale temperatures during the last (Eemian) interglacial, a simulation with a general circulation model (GCM) under orbital forcing conditions of 125 kyr BP is compared with a simulation forced with the Late Holocene preindustrial conditions. Consistent with previous GCM simulations for the Eemian, higher northern summer 2-m temperatures are found, which are directly related to the different insolation. Differences in the mean circulation are evident such as, for instance, stronger northern winter westerlies toward Europe, which are associated with warmer temperatures in central and northeastern Europe in the Eemian simulation, while the circulation variability, analyzed by means of a principal component analysis of the sea level pressure (SLP) field, is very similar in both periods. As a consequence of the differences in the mean circulation the simulated Arctic Oscillation (AO) temperature signal in the northern winter, on interannual-to-multidecadal time scales, is weaker during the Eemian than today over large parts of the Northern Hemisphere. Correlations between the AO index and the central European temperature (CET) decrease by about 0.2. The winter and spring SLP anomalies over the North Atlantic/European domain that are most strongly linearly linked to the CET cover a smaller area and are shifted westward over the North Atlantic during the Eemian. However, the strength of the connection between CET and these SLP anomalies is similar in both simulations. The simulated differences in the AO temperature signal and in the SLP anomaly, which is linearly linked to the CET, suggest that during the Eemian the link between the large-scale circulation and temperature-sensitive proxy data from Europe may differ from present-day conditions and that this difference should be taken into account when inferring large-scale climate from temperature-sensitive proxy data.

scholarly journals Estimates of the mean circulation in the deep (>2,000m) layer of the Eastern North Atlantic

1985 ◽  
Vol 14 ◽  
pp. 103-127 ◽  
Author(s):  
R.R. Dickson ◽  
W.J. Gould ◽  
T.J. Müller ◽  
C. Maillard
Keyword(s):  
North Atlantic ◽  
The Mean ◽  
Eastern North Atlantic ◽  
Mean Circulation

Study of a Non-Conventional Aeration System

1987 ◽  
Vol 19 (5-6) ◽  
pp. 869-876
Author(s):  
L. Raschid-Sally ◽  
M. Roustan ◽  
H. Roques ◽  
G. M. Faup
Keyword(s):  
Oxygen Transfer ◽  
Peclet Number ◽  
Péclet Number ◽  
Theoretical Approaches ◽  
Aeration System ◽  
Circulation Velocity ◽  
The Mean ◽  
Oxygen Transfer Capacity ◽  
Mean Circulation ◽  
Conventional Systems

A non-conventional aeration system for oxidation ditches using jets has been developed. The principle of this system is based on the separation of the 2 actions: aeration and circulation. It was concluded that the flow of the liquid in the channel can be successfully modelled using various theoretical approaches. The mean circulation velocity VC, the power dissipated P, and the Peclet number Pe are the 3 important parameters governing the circulation. The oxygen transfer capacity of the system has been studied and compares favourably with that of conventional systems. The advantage of such systems over conventional ones has been discussed.

Circulation of sympathectomized dogs under pentobarbital anesthesia

1965 ◽  
Vol 208 (4) ◽  
pp. 790-794
Author(s):  
Shu Chien ◽  
Shunichi Usami
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Blood Volume ◽  
Total Blood Volume ◽  
Central Blood Volume ◽  
Total Blood ◽  
Pentobarbital Anesthesia ◽  
Blood Flows ◽  
The Mean ◽  
Mean Circulation

In sympathectomized-splenectomized dogs under pentobarbital anesthesia, the total blood volume averaged 78 ml/kg, with 20% in the splanchnic circulation and 28% in the central blood volume. These values are almost the same as those found in the splenectomized (control) dogs with the sympathetic system intact. The over-all and the splanchnic Fcells factors are also not significantly different between these two groups. The sympathectomized animals had lower arterial pressure, cardiac output, and splanchnic blood flow, but the resistances calculated for the total and the splanchnic circulations were not significantly different from those of the control dogs. The mean circulation times for the total, the central, and the splanchnic circulations were all longer in the sympathectomized dogs. The data indicate that, under pentobarbital anesthesia, sympathectomized dogs are characterized by slower blood flows without any significant changes in either the blood volume or vascular resistance.

On the Mean Circulation in the Mid-Atlantic Bight

1979 ◽  
Vol 9 (3) ◽  
pp. 612-619 ◽  
Author(s):  
R. C. Beardsley ◽  
C. D. Winant
Keyword(s):  
The Mean ◽  
Mean Circulation

scholarly journals Observations and a Model of the Mean Circulation over the Middle Atlantic Bight Continental Shelf

2008 ◽  
Vol 38 (6) ◽  
pp. 1203-1221 ◽  
Author(s):  
Steven J. Lentz
Keyword(s):  
Pressure Gradient ◽  
Continental Shelf ◽  
Shallow Water ◽  
Water Depth ◽  
Circulation Pattern ◽  
Near Surface ◽  
Middle Atlantic ◽  
The Mean ◽  
Offshore Flow ◽  
Mean Circulation

Abstract Analyses of current time series longer than 200 days from 33 sites over the Middle Atlantic Bight continental shelf reveal a consistent mean circulation pattern. The mean depth-averaged flow is equatorward, alongshelf, and increases with increasing water depth from 3 cm s−1 at the 15-m isobath to 10 cm s−1 at the 100-m isobath. The mean cross-shelf circulation exhibits a consistent cross-shelf and vertical structure. The near-surface flow is typically offshore (positive, range −3 to 6 cm s−1). The interior flow is onshore and remarkably constant (−0.2 to −1.4 cm s−1). The near-bottom flow increases linearly with increasing water depth from −1 cm s−1 (onshore) in shallow water to 4 cm s−1 (offshore) at the 250-m isobath over the slope, with the direction reversal near the 50-m isobath. A steady, two-dimensional model (no along-isobath variations in the flow) reproduces the main features of the observed circulation pattern. The depth-averaged alongshelf flow is primarily driven by an alongshelf pressure gradient (sea surface slope of 3.7 × 10−8 increasing to the north) and an opposing mean wind stress that also drives the near-surface offshore flow. The alongshelf pressure gradient accounts for both the increase in the alongshelf flow with water depth and the geostrophic balance onshore flow in the interior. The increase in the near-bottom offshore flow with water depth is due to the change in the relative magnitude of the contributions from the geostrophic onshore flow that dominates in shallow water and the offshore flow driven by the bottom stress that dominates in deeper water.

scholarly journals Analysis of Atmospheric Energy Transport in ERA-40 and Implications for Simple Models of the Mean Tropical Circulation

2008 ◽  
Vol 21 (20) ◽  
pp. 5229-5241 ◽  
Author(s):  
Matthew E. Peters ◽  
Zhiming Kuang ◽  
Christopher C. Walker
Keyword(s):  
Total Energy ◽  
Vertical Velocity ◽  
Vertical Profile ◽  
Large Scale ◽  
Energy Transport ◽  
Tropical Circulation ◽  
The Mean ◽  
Atmospheric Energy Transport ◽  
Convergence Zones ◽  
Mean Circulation

Abstract An analysis of atmospheric energy transport in 22 years (1980–2001) of the 40-yr ECMWF Re-Analysis (ERA-40) is presented. In the analyzed budgets, there is a large cancellation between divergences of dry static and latent energy such that the total energy divergence is positive over all tropical oceanic regions except for the east Pacific cold tongue, consistent with previous studies. The west Pacific and Indian Oceans are characterized by a balance between diabatic sources and mean advective energy export, with a small eddy contribution. However, in the central and eastern Pacific convergence zone, total energy convergence by the mean circulation is balanced by submonthly eddies, with a small diabatic source. Decomposing the mean advective tendency into terms due to horizontal and vertical advection shows that the spatial variation in the mean advection is due largely to variations in vertical advection; these variations are further attributed to variations in the vertical profile of the vertical velocity. The eddy energy export, due almost exclusively to eddy moisture export, does not exhibit any significant seasonal variation. The relationship between the eddies and the mean circulation is examined. Large-scale moisture diffusion is correlated with eddy moisture export on (500 km)2 spatial scales, implying that eddy activity preferentially dries narrow convergence zones over wide ones. Eddy moisture export is further linked to the depth of mean convection in large-scale convergence zones with larger eddy export associated with shallower circulations. This suggests a mechanism that could contribute to the observed variation in mean divergence profiles across the northern tropical Pacific whereby sea surface temperature gradients set the width of convergence zones and eddy activity modulates the tropospheric relative humidity and divergence profile. The importance of variations in the vertical profile of the vertical velocity and eddies in closing the energy budget implies that simple models of the mean tropical circulation should include these effects.

scholarly journals Coupled wave and surge modelling and implications for coastal flooding

2008 ◽  
Vol 17 ◽  
pp. 19-22 ◽  
Author(s):  
J. Wolf
Keyword(s):  
Adriatic Sea ◽  
Storm Surges ◽  
Coastal Flooding ◽  
Irish Sea ◽  
Liverpool Bay ◽  
The Mean ◽  
Wave Models ◽  
The Uk ◽  
Mean Circulation

Abstract. The physical causes of coastal flooding due to marine storms are discussed. We examine the costs and impacts of storm surges and waves with reference to the UK. The mechanisms of interaction between waves and the mean circulation due to tides and wind are reviewed. A case study to illustrate the magnitude of surges, waves and their interactions is presented for Liverpool Bay in the eastern Irish Sea. Applications of surge and wave models to the Mediterranean, especially the Adriatic Sea, are considered.

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