scholarly journals The elements of the thermodynamic structure of the tropical atmosphere

2021 ◽  
Author(s):  
Jiawei Bao ◽  
Bjorn Stevens
Keyword(s):  
Tropical Atmosphere ◽  
Thermodynamic Structure

The elements of the thermodynamic structure of the tropical atmosphere

2020 ◽  
Author(s):  
Jiawei Bao ◽  
Bjorn Stevens
Keyword(s):  
Gravity Waves ◽  
Large Scale ◽  
Vertical Structure ◽  
Absolute Temperature ◽  
Adiabatic Process ◽  
Tropical Atmosphere ◽  
Large Scale Circulation ◽  
Thermodynamic Structure ◽  
The Absolute ◽  
Virtual Temperature

<p>Deep convection plays an important role in driving the large-scale circulation and the complex interaction between moist convection and the large-scale circulation regulates the thermodynamic structure of the tropical atmosphere.<span> </span></p><p>The convectional thoughts of the thermodynamic structure of the tropical atmosphere are that the horizontal temperature in the free troposphere is homogeneous, which is referred to as weak temperature gradient (WTG), while the vertical structure follows a moist-adiabatic lapse rate. However, it is not known how accurate WTG holds and which moist- adiabatic process the tropical atmosphere indeed experiences. This study centers around the horizontal and vertical structure of the tropical atmosphere and uses the global storm resolving simulations (GSRMs) from ICON at 2.5 km to investigate them</p><p>The virtual effect or the vapor buoyancy effect arises from that the molecular weight of water vapor is much smaller than that of dry air. With the same pressure and temperature, this virtual effect makes moist air lighter than dry air. As the horizontal buoyancy differences are eliminated by convection gravity waves, virtual temperature, a temperature variable including the moisture conditions, is expected to be homogeneous. Then, to obtain a homogeneous virtual temperature horizontally, the absolute temperature has to change to accommodate the horizontal moisture difference. The model results show that virtual temperature is relatively homogeneous at mid- and lower troposphere. Therefore, the virtual effect plays a very important role in the horizontal temperature structure, making the absolute temperature colder in moist regions and warmer in dry regions. However, in the upper troposphere, both the absolute temperature and the virtual temperature are not homogeneous, and vary as a function of moisture, indicating a weakening influence of convection gravity waves there.</p><p>We use saturation equivalent potential temperature (theta-es) to explore the vertical structure of the tropical atmosphere. Theta-es is expected to be conserved above the lifting condensation level (LCL) if calculated following the exact moist-adiabatic process that tropical atmosphere undergoes. The pseudo-adiabat and the reversible-adiabat with the effect of condensate loading are compared. To minimize the horizontal differences in theta-es due to moisture, we also define theta-es to account for the virtual effect and the condensate loading effect. The model results suggest that the actual moist-adiabatic process that tropical atmosphere experiences is between the pseudo-adiabat and the reversible-adiabat with the effect of condensate loading assuming air parcels originating from 972 hPa.<span> </span></p><p>The above results are broadly consistent with the results from ERA5 reanalysis.</p>

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

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

Modelling the ocean circulation and the basal melting in the Prydz Bay-Amery Ice Shelf system

2021 ◽  
Author(s):  
Jing Jin ◽  
Antony J. Payne ◽  
William Seviour ◽  
Christopher Bull
Keyword(s):  
Heat Transport ◽  
Ocean Circulation ◽  
Water Masses ◽  
Prydz Bay ◽  
Effect Of Temperature ◽  
Oceanic Circulation ◽  
Ice Shelf ◽  
Thermodynamic Structure ◽  
Amery Ice Shelf ◽  
Basal Melting

<p>The basal melting of the Amery Ice Shelf (AIS) in East Antarctica and its connections with the oceanic circulation are investigated by a regional ocean model. The simulated estimations of net melt rate over AIS from 1976 to 2005 vary from 1 to 2 m/yr depending primarily due to inflow of modified Circumpolar Deep Water (mCDW). Prydz Bay Eastern Costal Current (PBECC) and the eastern branch of Prydz Bay Gyre (PBG) are identified as two main mCDW intrusion pathways. The oceanic heat transport from both PBECC and PBG has significant seasonal variability, which is associated with the Antarctic Slope Current. The onshore heat transport has a long-lasting effect on basal melting. The basal melting is primarily driven by the inflowing water masses though a positive feedback mechanism. The intruding warm water masses destabilize the thermodynamic structure in the sub-ice shelf cavity therefore enhancing the overturning circulations, leading to further melting due to increasing heat transport. However, the inflowing saltier water masses due to sea-ice formation could offset the effect of temperature through stratifying the thermodynamic structure, then suppressing the overturning circulation and reducing the basal melting.</p>

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.

scholarly journals Study on swelling model and thermodynamic structure of native konjac glucomannan

2009 ◽  
Vol 10 (4) ◽  
pp. 273-279 ◽  
Author(s):  
Long Li ◽  
Hui Ruan ◽  
Liu-liu Ma ◽  
Wei Wang ◽  
Ping Zhou ◽  
...  
Keyword(s):  
Konjac Glucomannan ◽  
Thermodynamic Structure ◽  
Swelling Model
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