scholarly journals Analysis of different tropospheric energies in the surroundings of the Bay of Bengal during different cyclonic periods

MAUSAM ◽  
2021 ◽  
Vol 48 (3) ◽  
pp. 367-374
Author(s):  
M.D. MAHBUB ALAM ◽  
SULTANA SHAFEE

  ABSTRACT. Upper-air data of 0000 UTC for standard isobaric surfaces at surface, 850, 700, 500, 400, 300, 200, 150 and 100 hPa levels for the different cyclonic periods in the last decade were considered for study. The dry static energy, the latent heat energy, the moist static energy and the total energy and their vertical distribution were studied in the surroundings of the Bay of Bengal in relation to the movement of the cyclone and their ultimate landfall. The effects of different  tropospheric energies considering the pressure as a vertical coordinate are discussed with the help of graphs.    

MAUSAM ◽  
2021 ◽  
Vol 49 (2) ◽  
pp. 187-194
Author(s):  
SAMARENDRA KARMAKAR

The changes in the vertically-integrated tropospheric moisture. energy and their fluxes over Bangladesh have been studied during the landfall of three major cyclones at Bangladesh coast in the recent past. It has been found that the vertically- integrated tropospheric moisture, dry static energy, latent energy and total energy over the country have a tendency to decrease at the formation stages of the cyclones in the Bay of Bengal and then the same shows significant increase as the cyclones move northwards for ultimate landfall.   The integrated zonal and meridional fluxes of moisture, dry static energy, latent energy and total energy exhibit significant changes both in magnitudes and signs during the northward movement of the cyclones.


2011 ◽  
Vol 68 (8) ◽  
pp. 1806-1820 ◽  
Author(s):  
Kristofer Döös ◽  
Johan Nilsson

Abstract The atmospheric meridional overturning circulation is computed using the interim European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-Interim) data. Meridional mass transport streamfunctions are calculated not only using pressure as a vertical coordinate but also using temperature, specific humidity, and geopotential height as generalized vertical coordinates. Moreover, mass transport streamfunctions are calculated using the latent, the dry static, or the moist static energy as generalized vertical coordinates. The total meridional energy transport can be obtained by integrating these streamfunctions “vertically” over their entire energy range. The time-averaged mass transport streamfunctions are also decomposed into mean-flow and eddy-induced components. The meridional mass transport streamfunctions with temperature and specific humidity as independent variables yield a two-cell structure with a tropical Hadley-like cell and a pronounced extratropical Ferrel-like cell, which carries warm and moist air poleward. These Ferrel-like cells are much stronger than the Eulerian zonal-mean Ferrel cell, a feature that can be understood by considering the residual circulation related to specific humidity or temperature. Regardless of the generalized vertical coordinate, the present meridional mass transport streamfunctions yield essentially a two-layer structure with one poleward and one equatorward branch. The strongest meridional overturning in the midlatitudes is obtained when the specific humidity or the moist static energy is used as the vertical coordinate, indicating that the specific humidity is the variable that best distinguishes between poleward- and equatorward-moving air in the lower troposphere.


2020 ◽  
Author(s):  
Tiffany A Shaw ◽  
Robert J Graham

<p>Modern theories of the midlatitude storm tracks connect their intensity to surface baroclinicity (latitudinal surface temperature gradient). However, simulations show storm tracks were weaker during past cold, icy climates relative to the modern climate even though surface baroclinicity was stronger. We revisit this surface baroclinicity-intensity puzzle for Snowball Earth using simulations across the climate model hierarchy. Here we show the Moist Static Energy framework for storm track intensity solves the puzzle for Snowball Earth. It connects the weaker storm track to the increase of surface albedo, decrease of latent heat flux and decrease of latitudinal surface Moist Static Energy gradient. Weaker intensity can be predicted assuming a surface ice albedo and zero latent heat flux (large Bowen ratio) everywhere in Snowball Earth. The weaker storm track is also consistent with weaker Mean Available Potential Energy (weaker upper-tropospheric baroclinicity), however that cannot be predicted. Overall, the exotic Snowball Earth climate reveals storm track intensity follows the surface Moist Static Energy gradient and not surface baroclinicity. Our insights may help resolve the puzzle in other climates such as the Last Glacial Maximum.</p>


2020 ◽  
Author(s):  
Edward Groot ◽  
Holger Tost

<p>In this study we are trying to understand (limits of) predictability related to (organised) convection and its upscale error growth.</p><p>For that purpose we aim to analyse the impact of three convection driving and amplifying processes, namely latent heat release, redistribution of moist static energy and convective momentum transport on the development of the convective cells. Furthermore, we plan to investigate uncertainties in these processes on downward propagation of the flow and ensemble spread.</p><p>The first results to be presented regard an idealised and strongly organised case of splitting convective storms modeled at different resolutions and with some small adaptations in the model convective cloud resolving model CM1. Currently processed resolution experiments show that both the actual divergence field and the processes supected to underlie it exhibit some sensitivity to model resolution on the subkilometre scale (100-1000 m). We can also show that the upper tropospheric divergence can be directly related to the latent heat release, as it is located vertically above the major latent heat releases. Nevertheless, neither the vertical redistribution of moist static energy nor the convective momentum transport are negligible and all three impact the divergent outflow of the convective storm.</p>


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