Effect of latent heat release on mountain waves in a sheared mean flow

ABSTRACT. The effect of latent heat release on windward side of the mountain due to precipitation over the mountain waves has been studied assuming wind speed changing with respect to height. A single profile based on actual Peshawar data has been considered for the analysis. A thin level of heating has been chosen at medium level for the purpose of study. For non-hydrostatic case it is observed that in non-precipitation case when balanced heating/cooling takes place on the windward/leeward side or the mountain the effect of heating is negligibly small. However, for precipitation case downward displacement on the windward side, just above the level of heating. is obvious. Interference with the upstream current by the waves, produced due to elevated thermal forcing and reflected from the around surface is attributed to this phenomenon. Increase in the wave amplitude on the lee-side of the mountain as compared to non-precipitating case is also found. It is also revealed that higher the level or heating lesser the amplitude of the induced disturbance. 4.5 km agl is the level which is maximum affected by heating in general. For large and shallow mountainous terrains. hydrostatic solutions have been produced for three different levels of heating for sheared flow, Streamlines have been drawn. On comparison with no shear case, it may be inferred that shear effect is opposite to that due to thermal forcing.

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The Sensitivity of Persistent Geopotential Anomalies to the Climate of a Moist Channel Model

Journal of Climate ◽

10.1175/jcli-d-20-0254.1 ◽

2021 ◽

pp. 1-52

Author(s):

Gregory Tierney ◽

Walter A. Robinson ◽

Gary Lackmann ◽

Rebecca Miller

Keyword(s):

Climate Change ◽

Heat Release ◽

Latent Heat ◽

Channel Model ◽

Heat Waves ◽

Latent Heat Release ◽

Mean Flow ◽

Flow Variability ◽

Virtual Temperature ◽

Channel Configuration

AbstractHigh-impact events such as heat waves and droughts are often associated with persistent positive geopotential height anomalies (PAs). Understanding how PA activity will change in a future warmer climate is therefore fundamental to projecting associated changes in weather and climate extremes. This is a complex problem because the dynamics of PAs and their associated blocking activity are still poorly understood. Furthermore, climate-change influences on PA activity may be geographically dependent and encompass competing influences. To expose the salient impacts of climate change, we use an oceanic channel configuration of the Weather Research and Forecasting model (WRF) in a bivariate experiment focused on changes in environmental temperature, moisture, and baroclinicity. The 500-hPa wind speed and flow variability are found to increase with increasing temperature and baroclinicity, driven by increases in latent heat release and a stronger virtual temperature gradient. Changes to 500-hPa sinuosity are negligible. PAs are objectively identified at the 500-hPa level using an anomaly threshold method. When using a fixed threshold, PA trends indicate increased activity and strength with warming, but decreased activity and strength with Arctic amplification. Use of a climate-relative threshold hides these trends and highlights the importance of accurate characterization of the mean flow. Changes in PA activity mirror corresponding changes in 500-hPa flow variability and are found to be attributable to changes in three distinct dynamical mechanisms: baroclinic wave activity, virtual temperature effects, and latent heat release.

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Change in inter-atomic communication character in the formation of solid and liquid solutions. Relationship of vibrational and configuration entropy and their physical interpretation

Voprosy Materialovedeniya ◽

10.22349/1994-6716-2021-105-1-28-40 ◽

2021 ◽

pp. 28-40

Author(s):

A. M. Savchenko ◽

Yu. V. Konovalov ◽

A. V. Laushkin

Keyword(s):

Heat Capacity ◽

Heat Release ◽

Latent Heat ◽

Physical Interpretation ◽

Latent Heat Release ◽

Statistical Entropy ◽

Average Heat ◽

Configuration Entropy ◽

Liquid Solutions ◽

Relationship Of

The purpose of this work is to show that during mixing, two hidden (latent) processes proceed simultaneously and compensate each other: the first initiates an increase in the average heat capacity, equal in magnitude to the entropy of mixing, which requires energy absorption to ensure a constant temperature, the second initiates simultaneous latent heat release by strengthening interatomic bonds. The passage of these two processes during mixing shows the identity of the vibrational and configurational (statistical) entropy.

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Measurement and Modeling of Latent Heat Release During Freezing of Aqueous Solutions in a Small Container

10.1115/imece2000-2217 ◽

2000 ◽

Author(s):

Ramachandra V. Devireddy ◽

John C. Bischof ◽

Perry H. Leo ◽

John S. Lowengrub

Keyword(s):

Mass Transport ◽

Heat Release ◽

Latent Heat ◽

Pure Water ◽

Heat Of Fusion ◽

Freezing Process ◽

Latent Heat Release ◽

Aqueous Systems ◽

Heat And Mass Transport ◽

Latent Heat Of Fusion

Abstract The latent heat of fusion, ΔHf of a cryobiological medium (a solute laden aqueous solution) is a crucial parameter in the cryopreservation process. The latent heat has often been approximated by that of pure water (∼ 335 mJ/mg). However, recent calorimetric (DSC - Pyris 1) measurements suggest that the actual magnitude of latent heat of fusion during freezing of solute laden aqueous systems is far less. Fourteen different pre-nucleated solute laden aqueous systems (NaCl-H2O, Phosphate Buffered Saline or PBS, serum free RPMI, cell culture medium, glycerol and Anti Freeze Protein solutions) were found to have significantly lower ΔHf than that of pure water (Devireddy and Bischof, 1998). In the present study additional calorimetric experiments are performed at 1, 5 and 20 °C/min in five representative cryobiological media (isotonic or 1× NaCl-H2O, 10× NaCl-H2O, 1× PBS, 5× PBS and 10× PBS) to determine the kinetics of ice crystallization. The temperature (T) and time (t) dependence of the latent heat release is measured. The experimental data shows that at a fixed temperature, the fraction of heat released at higher cooling rates (5 and 20 °C/min) is lower than at 1 °C/min for all the solutions studied. We then sought a simple model that could predict the experimentally measured behavior and examined the full set of heat and mass transport equations during the freezing process in a DSC sample pan. The model neglects the interaction between the growing ice crystals and is most appropriate during the early stages of the freezing process. An examination of the coefficients in the heat and mass transport equations shows that heat transport occurs much more rapidly than solute transport. Hence, the full model reduces to one in which the temperature profile is constant in space while the solute concentration profile obeys the full time and space dependent diffusion equation. The model reveals the important physical parameters controlling the mass transport at the freezing interface and further elucidates the experimental results, i.e. the temperature and time dependence of the latent heat release.

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Moist versus Dry Baroclinic Instability in a Simplified Two-Layer Atmospheric Model with Condensation and Latent Heat Release

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-11-0205.1 ◽

2012 ◽

Vol 69 (4) ◽

pp. 1405-1426 ◽

Cited By ~ 25

Author(s):

Julien Lambaerts ◽

Guillaume Lapeyre ◽

Vladimir Zeitlin

Keyword(s):

Life Cycle ◽

Heat Release ◽

Latent Heat ◽

Baroclinic Instability ◽

Underlying Mechanism ◽

Linear Instability ◽

Vapor Condensation ◽

Water Model ◽

Finite Volume Scheme ◽

Latent Heat Release

Abstract The authors undertake a detailed analysis of the influence of water vapor condensation and latent heat release upon the evolution of the baroclinic instability. The framework consists in a two-layer rotating shallow-water model with moisture coupled to dynamics through mass exchange between the layers due to condensation/precipitation. The model gives all known in literature models of this kind as specific limits. It is fully nonlinear and ageostrophic. The reference state is a baroclinic Bickley jet. The authors first study its “dry” linear instability and then use the most unstable mode to initialize high-resolution numerical simulations of the life cycle of the instability in nonprecipitating (moisture being a passive tracer) and precipitating cases. A new-generation well-balanced finite-volume scheme is used in these simulations. The evolution in the nonprecipitating case follows the standard cyclonic wave-breaking life cycle of the baroclinic instability, which is reproduced with a high fidelity. In the precipitating case, the onset of condensation significantly increases the growth rate of the baroclinic instability at the initial stages due to production of available potential energy by the latent heat release. Condensation occurs in frontal regions and wraps up around the cyclone, which is consistent with the moist cyclogenesis theory and observations. Condensation induces a clear-cut cyclone–anticyclone asymmetry. The authors explain the underlying mechanism and show how it modifies the equilibration of the flow at the late stages of the saturation of the instability. In spite of significant differences in the evolution, only weak differences in various norms of the perturbations remain between precipitating and nonprecipitating cases at the end of the saturation process.

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Upper atmosphere tidal variability due to latent heat release in the tropical troposphere

Advances in Space Research ◽

10.1016/s0273-1177(99)00873-x ◽

1999 ◽

Vol 24 (11) ◽

pp. 1515-1521 ◽

Cited By ~ 4

Author(s):

J.M. Forbes ◽

M.E. Hagan ◽

X. Zhang ◽

J. Hackney

Keyword(s):

Heat Release ◽

Latent Heat ◽

Upper Atmosphere ◽

Latent Heat Release ◽

Tropical Troposphere ◽

Tidal Variability

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Effects of latent heat release at phase boundaries on flow in the Earth’s mantle, phase boundary topography and dynamic topography at the Earth’s surface

Physics of The Earth and Planetary Interiors ◽

10.1016/j.pepi.2007.04.021 ◽

2007 ◽

Vol 164 (1-2) ◽

pp. 2-20 ◽

Cited By ~ 73

Author(s):

Bernhard Steinberger

Keyword(s):

Heat Release ◽

Phase Boundary ◽

Latent Heat ◽

Latent Heat Release ◽

Dynamic Topography ◽

Phase Boundaries ◽

Earth’S Mantle

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Atmospheric Dynamics Triggered by an Oceanic SST Front in a Moist Quasigeostrophic Model

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-11-0288.1 ◽

2012 ◽

Vol 69 (5) ◽

pp. 1617-1632 ◽

Cited By ~ 17

Author(s):

Bruno Deremble ◽

Guillaume Lapeyre ◽

Michael Ghil

Keyword(s):

Heat Flux ◽

Heat Release ◽

Latent Heat ◽

Sensible Heat Flux ◽

Sensible Heat ◽

Latent Heat Release ◽

Sst Front ◽

Moist Processes ◽

Surface Sensible Heat Flux ◽

Sst Fronts

Abstract To understand the atmospheric response to a midlatitude oceanic front, this paper uses a quasigeostrophic (QG) model with moist processes. A well-known, three-level QG model on the sphere has been modified to include such processes in an aquaplanet setting. Its response is analyzed in terms of the upper-level atmospheric jet for sea surface temperature (SST) fronts of different profiles and located at different latitudes. When the SST front is sufficiently strong, it tends to anchor the mean atmospheric jet, suggesting that the jet’s spatial location and pattern are mainly affected by the latitude of the SST front. Changes in the jet’s pattern are studied, focusing on surface sensible heat flux and on moisture effects through latent heat release. It is found that latent heat release due to moist processes is modified when the SST front is changed, and this is responsible for the meridional displacement of the jet. Moreover, both latent heat release and surface sensible heat flux contribute to the jet’s strengthening. These results highlight the role of SST fronts and moist processes in affecting the characteristics of the midlatitude jet stream and of its associated storm track, particularly their positions.

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Mechanisms of Future Predicted Changes in the Zonal Mean Mid-Latitude Circulation

Current Climate Change Reports ◽

10.1007/s40641-019-00145-8 ◽

2019 ◽

Vol 5 (4) ◽

pp. 345-357 ◽

Cited By ~ 5

Author(s):

Tiffany A. Shaw

Keyword(s):

Heat Release ◽

Latent Heat ◽

Climate Models ◽

Static Stability ◽

Hadley Cell ◽

Specific Humidity ◽

Latent Heat Release ◽

Starting Point ◽

Intensity Changes ◽

The Tropics

AbstractState-of-the-art climate models predict the zonal mean mid-latitude circulation will undergo a poleward shift and seasonally and hemispherically dependent intensity changes in the future. Here I review the mechanisms put forward to explain the zonal mean mid-latitude circulation response to increased carbon dioxide (CO2) concentration. The mechanisms are grouped according to their thermodynamic starting point, which are thought to arise from processes independent of the zonal mean mid-latitude circulation response. There are 24 mechanisms and 8 thermodynamic starting points: (i) increased latent heat release aloft in the tropics, (ii) increased dry static stability and tropopause height outside the tropics, (iii) radiative cooling of the stratosphere, (iv) Hadley cell expansion, (v) increased specific humidity following the Clausius-Clapeyron relation, (vi) cloud radiative effect changes, (vii) turbulent surface heat flux changes, and (viii) decreased surface meridional temperature gradient. I argue progress can be made by testing the thermodynamic starting points. I review recent tests of the increased latent heat release aloft in the tropics starting point, i.e., prescribing diabatic perturbations, quantifying the transient response to an abrupt CO2 increase and imposing latitudinally dependent CO2 concentration. Finally, I provide a future outlook for improving our understanding of predicted changes in the zonal mean mid-latitude circulation.

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