scholarly journals Can geostrophic adjustment of baroclinic disturbances in the tropical atmosphere explain MJO events?

2020 ◽  
Vol 146 (733) ◽  
pp. 3998-4013
Author(s):  
Masoud Rostami ◽  
Vladimir Zeitlin
Keyword(s):  
Tropical Atmosphere ◽  
Geostrophic Adjustment

scholarly journals Numerical Simulations of a Gravity Wave Event over CCOPE. Part I: The Role of Geostrophic Adjustment in Mesoscale Jetlet Formation

1997 ◽  
Vol 125 (6) ◽  
pp. 1185-1211 ◽  
Author(s):  
Michael L. Kaplan ◽  
Steven E. Koch ◽  
Yuh-Lang Lin ◽  
Ronald P. Weglarz ◽  
Robert A. Rozumalski
Keyword(s):  
Numerical Simulations ◽  
Gravity Wave ◽  
Geostrophic Adjustment ◽  
Wave Event

Ten years outdoor exposure of steel in an urban and coastal tropical atmosphere

2021 ◽  
pp. 1-8
Author(s):  
Juan A. Jaén ◽  
Kevin Guzmán ◽  
Josefina Iglesias ◽  
Griselda Caballero Manrique
Keyword(s):  
Outdoor Exposure ◽  
Tropical Atmosphere

Corrosive aggressiveness of tropical atmosphere of island of Cuba (Review)

2021 ◽  
pp. 16-25
Author(s):  
M. I. Daskovsky ◽  
◽  
E. A. Shein ◽  
D. V. Sevastyanov ◽  
M. S. Doriomedov ◽  
...  
Keyword(s):  
Tropical Atmosphere

scholarly journals Observing the Tropical Atmosphere in Moisture Space

2018 ◽  
Vol 75 (10) ◽  
pp. 3313-3330 ◽  
Author(s):  
Hauke Schulz ◽  
Bjorn Stevens
Keyword(s):  
Large Scale ◽  
Deep Convection ◽  
Circulation Pattern ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Low Rank ◽  
Substantial Part ◽  
Tropical Atmosphere ◽  
Shallow Clouds ◽  
Self Aggregation

Measurements from the Barbados Cloud Observatory are analyzed to identify the processes influencing the distribution of moist static energy and the large-scale organization of tropical convection. Five years of water vapor and cloud profiles from a Raman lidar and cloud radar are composed to construct the structure of the observed atmosphere in moisture space. The large-scale structure of the atmosphere is similar to that now familiar from idealized studies of convective self-aggregation, with shallow clouds prevailing over a moist marine layer in regions of low-rank humidity, and deep convection in a nearly saturated atmosphere in regions of high-rank humidity. With supplementary reanalysis datasets the overall circulation pattern is reconstructed in moisture space, and shows evidence of a substantial lower-tropospheric component to the circulation. This shallow component of the circulation helps support the differentiation between the moist and dry columns, similar to what is found in simulations of convective self-aggregation. Radiative calculations show that clear-sky radiative differences can explain a substantial part of this circulation, with further contributions expected from cloud radiative effects. The shallow component appears to be important for maintaining the low gross moist stability of the convecting column. A positive feedback between a shallow circulation driven by differential radiative cooling and the low-level moisture gradients that help support it is hypothesized to play an important role in conditioning the atmosphere for deep convection. The analysis suggests that the radiatively driven shallow circulations identified by modeling studies as contributing to the self-aggregation of convection in radiative–convective equilibrium similarly play a role in shaping the intertropical convergence zone and, hence, the large-scale structure of the tropical atmosphere.

Eddy formation by dense flows on slopes in a rotating fluid

1998 ◽  
Vol 363 ◽  
pp. 229-252 ◽  
Author(s):  
GREGORY F. LANE-SERFF ◽  
PETER G. BAINES
Keyword(s):  
Ocean Circulation ◽  
Laboratory Experiments ◽  
Lower Layer ◽  
Ekman Layer ◽  
Global Ocean ◽  
Circulation System ◽  
Geostrophic Adjustment ◽  
Viscous Effects ◽  
Dense Fluid ◽  
Global Ocean Circulation

Properties of the flow generated by a continuous source of dense fluid on a slope in a rotating system are investigated with a variety of laboratory experiments. The dense fluid may initially flow down the slope but it turns (under the influence of rotation) to flow along the slope, and initial geostrophic adjustment gives it an anticyclonic velocity profile. Some of the dense fluid drains downslope in a viscous Ekman layer, which may become unstable to growing waves. Provided that the viscous draining is not too strong, cyclonic vortices form periodically in the upper layer and the dense flow breaks up into a series of domes. Three processes may contribute to the formation of these eddies. First, initial downslope flow of the dense current may stretch columns of ambient fluid by the ‘Taylor column’ process (which we term ‘capture’). Secondly, the initial geostrophic adjustment implies lower-layer collapse which may stretch the fluid column, and thirdly, viscous drainage will progressively stretch and spin up a captured water column. Overall this last process may be the most significant, but viscous drainage has contradictory effects, in that it progressively removes dense lower-layer fluid which terminates the process when the layer thickness approaches that of the Ekman layer. The eddies produced propagate along the slope owing to the combined effects of buoyancy–Coriolis balance and ‘beta-gyres’. This removes fluid from the vicinity of the source and causes the cycle to repeat. The vorticity of the upper-layer cyclones increases linearly with Γ=Lα/D (where L is the Rossby deformation radius, α the bottom slope and D the total depth), reaching approximately 2f in the experiments presented here. The frequency at which the eddy/dome structures are produced also increases with Γ, while the speed at which the structures propagate along the slope is reduced by viscous effects. The flow of dense fluid on slopes is a very important part of the global ocean circulation system and the implications of the laboratory experiments for oceanographic flows are discussed.

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