Analytical solutions for thermal forcing vortices in boundary layer and its applications

Using the Boussinesq approximation, the vortex in the boundary layer is assumed to be axisymmetrical and thermal-wind balanced system forced by diabatic heating and friction, and is solved as an initial-value problem of linearized vortex equation set in cylindrical coordinates. The impacts of thermal forcing on the flow field structure of vortex are analyzed. It is found that thermal forcing has significant impacts on the flow field structure, and the material representative forms of these impacts are closely related to the radial distribution of heating. The discussion for the analytical solutions for the vortex in the boundary layer can explain some main structures of the vortex over the Tibetan Plateau.

QBO-like Oscillations Induced by Local Thermal Forcing

A zonalwetiCal two-dimensional equatorial model is used to study the PO￣ty that the long Period oSCillation of the zonal mean now occurring in the lower equatorial stratosphere(QBO) is cause by local thermal activihes at the tropiCal tropopause.The model sumesfully reproduces Q￣like o￣tions of the zonal mean now,suggeshng that the lOCal heating or cooling at the trOPical trOPOpose is Probably the main ￣n of QBO,s generahon. The analysis of the dependence of the oedllahon on the wave foeing iudicatw that the o￣hon is not areaible to the forCing scale.The model can reproduce QBO--like oscillahons with any forCing￣if the forcing Period and amplitude take appropriate valuex, proving that the inaneal cavity waves ge￣od by lOCal thermal sough take much important roles in QBO.

Transient Free Convection and Heat Transfer in a Partitioned Attic-Shaped Space under Diurnal Thermal Forcing

One primordial consideration in residential ventilation standards is the comfort of provided to people living in those habitations.This is highly dependent on the thermal and fluid flow conditions,the space geometry and so on.Efficient designs may reduce the energy usage,making the buildings more sustainable over a longer period of time.This study aims to investigate the impact of whole day thermal conditions on the fluid flow structure and heat transfer phenomena,mainly natural convection,inside a partitioned attic-shaped configuration.The Finite Volume Method is applied to solve the governing equations.Sinusoidal thermal boundary condition is applied on the sloping walls to illustrate the characteristics of primary flow through daily cycles.A highly thermal conductive partition was placed vertically at the middle of the cavity.Note that through the partition,only heat could freely transfer between two fluid zones.Results show that,during day time,a stratified fluid flow structure is obtained,which originates from the prevailing conduction heat transfer mechanism,while,for the night-time it changed into a strong convection mechanism which significantly affects the flow structure.These results are particularly important for understanding the fluid dynamics inside the attic shaped building and also designing new residential building.

EFFECT OF THE THERMAL FORCING ON THE SECONDARY CIRCULATION OF TYPHOONS

A non-dimensional secondary circulation equation for typhoons has been derived and then 11-yr com- positing typhoon data were used to estimate the thermally forced secondary circulation.The main results have been obtained as follows: (1)The diabatic heating and Cu vertical heat mixing are major thermal forcing factors.They have the same magnitude of order.(2)The effects of eddy flux and Cu horizontal mixing of heat are of minor im- portance.(3)Ekman pumping and Cu vertical heat mixing cooperatively work.This feedback process is favorable for the enhancement of the secondary circulation of typhoons.

MULTIPLE EQUILIBRIA IN BAROCLINIC ATMOSPHERE BY THERMAL FORCING RELATED TO SUBTROPICAL HIGH

By using Lorenz’s moist general circulation model, a nonlinear and dissipative system describing atmospheric motion has been obtained in approximation of Low Order.The multiple equilibria and the transformation between the flow patterns of winter and summer, the latitudinal oscillation of subtropical high by thermal forcing and nonlinear interaction of general circulation are studied in this paper.The results show that the transformation of flow patterns is a discontinuous leaping, and is a process of resetting new flow pattern by rapid exchange inflow field.In the corresponding dry model, we cannot find the latitudinal oscillation of the center of subtropical high.In the moist model, after the thermal effect of water vapor is drawn into the model, nonlinear interaction appears between flow and heating fields.This effect helps to bring about the latitudinal oscillation of subtropical high.

SOLITON-LIKE THERMAL SOURCE FORCING AND SINGULAR RESPONSE OF ATMOSPHERE AND OCEANS TO IT

Nonlinear dynamic study is undertaken of the response of atmospheric and oceanic flow fields to local thermal source forcing in the context of a generalized geophysical fluid dynamic barotropic quasi_geostrophic model, discovering a good relation between thermal disturbance and flow field response to it, both having similar modes, and that the soliton_like responding field is a great deal larger in extent than the analogous_form forcing field, which implies that a 'narrow' thermal disturbance can excite a 'wide' response field, in some cases the particular structure of a thermal source may give rise to singular response of atmospheric and oceanic flow fields, thus displaying their abnormalities (for example the blocking situation in the atmosphere), the atmospheric and oceanic stream fields at mid_high latitudes respond to thermal forcing in a much more pronounced manner compared to those at low latitudes. The said research results that is in agreement with studies from mid_low latitude atmospheric experiments and observations and can be used to partially interpret the circulation singularity due to heat source anomaly on a local basis in the context of earch fluid flows.

Convective Initiation by Topographically Induced Convergence Forcing over the Dabie Mountains on 24 June 2010

The initiation of convective cells in the late morning of 24 June 2010 along the eastward extending ridge of the Dabie Mountains in the Anhui region, China, is studied through numerical simulations that include local data assimilation. A primary convergence line is found over the ridge of the Dabie Mountains, and along the ridge line several locally enhanced convergence centers preferentially initiate convection. Three processes responsible for creating the overall convergence pattern are identified. First, thermally-driven upslope winds induce convergence zones over the main mountain peaks along the ridge, which are shifted slightly downwind in location by the moderate low-level easterly flow found on the north side of a Mei-yu front. Second, flows around the main mountain peaks along the ridge create further convergence on the lee side of the peaks. Third, upslope winds develop along the roughly north-south oriented valleys on both sides of the ridge due to thermal and dynamic channeling effects, and create additional convergence between the peaks along the ridge. The superposition of the above convergence features creates the primary convergence line along the ridge line of the Dabie Mountains. Locally enhanced convergence centers on the primary line cause the initiation of the first convection cells along the ridge. These conclusions are supported by two sensitivity experiments in which the environmental wind （dynamic forcing） or radiative and land surface thermal forcing are removed, respectively. Overall, the thermal forcing effects are stronger than dynamic forcing given the relatively weak environmental flow.

Numerical and Dynamical Analyses of Heat Source Forcingand Restricting Subtropical High Activity

By using the numerical and dynamical methods, the influence and restriction of the heat source forcing on the subtropical geopotential fields and flow fields are studied and discussed in a model atmosphere. The main results show that the zonal symmetrical solar radiation heating chief-ly induces the geopotential field changing gradually and leads the subtropical high moving slowly, but when the zonal asymmetric thermal difference between ocean and continent achieves its critical value, which usually causes the geopotential field a catastrophe, and consequently induces the subtropical high shake-up or jump. The abnormal activity of the subtropical high is possibly caused by the abnormality of the thermal factor. Key words Subtropical high - Thermal forcing Supported by National Natural Science Foundation (No. 49975012) and National ’ 973’ Key Program (No. G1998040907).

TEMPERATURE PROFILES OF LOCAL THERMAL NONEQUILIBRIUM FOR THERMAL DEVELOPING FORCED CONVECTION IN POROUS MEDIUM PARALLEL PLATE CHANNEL

Based on the two-energy equation model, taking into account viscous dissipation due to the interaction between solid skeleton and pore fluid flow, temperature expressions of the solid skeleton and pore fluid flow are obtained analytically for the thermally developing forced convection in a saturated porous medium parallel plate channel, with walls being at constant temperature. It is proved that the temperatures of the two phases for the local thermal nonequilibrium approach to the temperature derived from the one-energy equation model for the local thermal equilibrium when the heat exchange coefficient goes to infinite. The temperature profiles are shown in figures for different dimensionless parameters and the effects of the parameters on the local thermal nonequilibrium are revealed by parameter study.

Three-Dimensional Thermal-Stress Analysis of Semi-infinite Transversely Isotropic Composites

By making use of the direct integration method,an exact analysis of the general three-dimensional thermoelasticity problem is performed for the case of a transversely isotropic homogeneous half-space subject to local thermal and force loadings.The material plane of isotropy is assumed to be parallel to the limiting surface of the halfspace.By reducing the original thermoelasticity equations to the governing ones for individual stress-tensor components,the effect of material anisotropy in the stress field is analyzed with regard to the feasibility requirement,i.e.,the finiteness of the stress field at a distance from the disturbed area.As a result,the solution is constructed in the form of explicit analytical dependencies on the force and thermal loadings for various kinds of transversely isotropic materials and agrees with the basic principles of the continua mechanics.The solution can be efficiently used as a benchmark one for the direct computation of temperature and thermal stresses in transversely isotropic semi-infinite domains,as well as for the verification of solutions constructed by different means.

High-Fidelity Hugoniots of α Phase RDX Solid from High-Quality Force Field with Thermal,Zero-Point Vibration,and Anharmonic Effects

It is shown that the introduction of thermal effect, zero-point vibration, and phonon anharmonicity to a high quality and first-principle-Sased force field （atomic potential） results in a significant improvement in predict- ing the densities for the α phase crystalline hexahydro-1,3,5-trinitro-l,3,5-triazine （RDX）, and derivation of its high-fidelity Hugoniot locus and Mie-Grfineisen equation of state covering a very wide range of pressures and temperatures. This work can be used to efficiently and accurately predict the thermophysical properties of solid explosives over the pressures and temperatures to which they are subjected, which is a long-standing issue in the field of energetic materials.

Occurrence Mechanism of A Local Rainstorm in the Northwest of Hubei Province

A rare local rainstorm weather in the midsummer rainy weather process appeared in the northwest of Hubei Province during July 8-13,2009.The circulation situation,the contributions of dynamic,thermal force and water vapor to this strong precipitation in this process were discussed.The results showed that the cold air which was brought by Lake Balkis cold vortex was the trigger mechanism of local rainstorm,and Lake Baikal low pressure provided the foreign dynamic for the adjustment of East Asia circulation.When the rainstorm occurred,the divergence in the divergence field had the strong 'pumping effect' in the high altitude.The warm wet airflow in the Bay of Bengal and the South China Sea was the water vapor source of rainstorm.The falling zone of rainstorm appeared in the front of energy frontal zone,and the axis line in the top of high-energy tongue deviated to the side of cold air.Q vector divergence and the negative value zone of water vapor helicity had the important indication effect for the short-term forecast of local rainstorm.

The Effect of Transient Eddy on Interannual Meridional Displacement of Summer East Asian Subtropical Jet

Using ERA-40 reanalysis daily data for the period 1958-2002, this study investigated the effect of tran- sient eddy （TE） on the interannual meridional displacement of summer East Asian subtropical jet （EASJ） by conducting a detailed dynamical diagnosis. The summer EASJ axis features a significant interannual coherent meridional displacement. Associated with such a meridional displacement, the TE vorticity forcing anomalies are characterized by a meridional dipole pattern asymmetric about the climatological EASJ axis. The TE vorticity forcing anomalies yield barotropic zonal wind tendencies with a phase meridionally lead- ing the zonal wind anomalies, suggesting that they act to reinforce further meridional displacement of the EASJ and favor a positive feedback in the TE and time-mean flow interaction. However, The TE thermal forcing anomalies induce baroclinic zonal wind tendencies that reduce the vertical shear of zonal wind and atmospheric baroclinicity and eventually suppress the TE activity, favoring a negative feedback in the TE and time-mean flow interaction. Although the two types of TE forcing tend to have opposite feedback roles, the TE vorticity forcing appears to be dominant in the TE effect on the time-mean flow.

Dynamic and Numerical Study of Waves in the Tibetan Plateau Vortex

In terms of its dynamics, The Tibetan Plateau Vortex （TPV） is assumed to be a vortex in the botmdary layer forced by diabatic heating and friction. In order to analyze the basic characteristics of waves in the vortex, the governing equations for the vortex were established in column coordinates with the balance of gradient wind. Based on this, the type of mixed waves and their dispersion characteristics were deduced by solving the linear model. Two numerical simulations with triple-nested domains--one idealized large-eddy simulation and one of a TPV that took place on 14 August 2006---were also carried out. The aim of the simulations was to validate the mixed wave deduced from the governing equations. The high-resolution model output data were analyzed and the results showed that the tangential flow field of the TPV in the form of center heating was cyclonic and convergent in the lower levels and anticyclonic and divergent in the upper levels. The simulations also showed that the vorticity of the vortex is uneven and might have shear flow along the radial direction. The changing vorticity causes the formation and spreading of vortex Rossby （VR） waves, and divergence will cause changes to the n^otion of the excitation and evolution of inertial gravity （IG） waves. Therefore, the vortex may contain what we call mixed ：inertial gravity-vortex Rossby （IG-VR） waves. It is suggested that some strongly developed TPVs should be studied in the future, because of their effects on weather in downstream areas.

Influence of the Tibetan Plateau on the Summer Climate Patterns over Asia in the IAP/LASG SAMIL Model

A series of numerical experiments are carried out by using the Spectral Atmospheric Model of State Key Laboratory of Numerical Modeling Atmospheric Sciences and Geophysical Fluid Dynamics/Institute of Atmospheric Physics （SAMIL） to investigate how the Tibetan Plateau （TP） mechanical and thermal forcing affect the circulation and climate patterns over subtropical Asia. It is shown that, compared to mechanical forcing, the thermal forcing of TP plays a dominant role in determining the large-scale circulation in summer. Both the sensible heating and the latent heating over TP tend to generate a surface cyclonic circulation and a gigantic anticyclonic circulation in the mid- and upper layers, whereas the direct effect of the latter is much more significant. Following a requirement of the time-mean quasi-geostrophic vorticity equation for large-scale air motion in the subtropics, convergent flow and vigorous ascending motion must appear to the east of TP. Hence the summer monsoon in East China is reinforced efficiently by TP. In contrast, the atmosphere to the west of TP is characterized by divergent flow and downward motion, which induces the arid climate in Mid-Asia.

MODULATION OF ATMOSPHERIC THERMAL AND MECHANICAL FORCINGS AND NUMERICAL MODELING OF MEAN MERIDIONAL CIRCULATION

Upon investigating the relative locations of internal and external forcing and the resultant mean meridional circula- tion,it was found that thermal forcing and mechanical forcing for the formation of atmospheric mean meridional circu- lation are modulated by a certain ratio.This ratio is determined by the inherent baroclinity,static stability and absolute vorticity of the atmosphere. By employing a parameterization scheme for radiative heating and condensation heating,together with the analysis data of the European Center for Medium-range Weather Forecasts,the mean meridional circulation for January was simulated numerically.It was found that latent heat release in the tropics may result in the formation of double-layered Hadley circulation,so do the eddy momentum transfer processes.On the other hand,mean meridional circulations in ex- tra-tropics are mainly determined by external momentum forcing and atmospheric properties of eddy momentum and heat transfer.

Low-Frequency CISK-Rossby Wave and Stratospheric QBO in the Tropical Atmosphere

Dynamic study is undertaken of the tropical atmospheric CISK-Rossby wave genesis and propagation mechanisms, the vertical structure of the low-frequency wave and the basic characteristics and constraint of the vertical transport of momentum and wave energy fluxes in relation to the quasi-biennial oscillation (QBO) of the stratospheric zonal winds over the tropics in the context of a baroclinic quasi-geostrophic model. Results suggest that in the properly posed thermal conditions and zonal belt there exist two kinds of CISK-Rossby waves of low frequency (LF) and very low frequency (VLF), travelling zonally in opposite directions, which act as sources responsible for upward transferring momentum and wave energy fluxes for easterly and westerly perturbations in such a way as to provide required momentum and energy for the stratospheric QBO genesis and maintenance. The present study offers interpretations for some of the fundamental observational facts of the QBO and proposes new ideas of the QBO generation mechanism.

Linear Global Temperature Correlation to Carbon Dioxide Level, Sea Level, and Innovative Solutions to a Projected 6°C Warming by 2100

Too many climate committees, conferences, articles and publications continue to suggest a one and a half (1.5°C) to two degrees (2°C) Celsius as an achievable global limit to climate changes without establishment of any causal link to the proposed anti-warming mechanism. A comprehensive review has found instead that observationally informed projections of climate science underlying climate change offer a different outlook of five to six-degree (5°C - 6°C) increase as “most accurate” with regard to present trends, climate history and models, yielding the most likely outcome for 2100. The most causative triad for the present warming trend from 1950 to the present is identified in this paper: 1) the tripling (3×) of world population;2) the quadrupling (4×) of carbon emissions;and 3) the quintupling (5×) of the world energy consumption. This paper presents a quantitative, linear global temperature correlation to carbon dioxide levels that has great predictive value, a short temporal feedback loop, and the finding that it is also reversible. The Vostok ice core temperature and CO2 values for the past 400,000 years, with past sea level estimates have produced the sufficiently evidential “Hansen’s Graph”. Detailed analysis results in an equation for global average temperature change and an indebted, long-term sea level rise, from even a 20 ppm of CO2 change above 290 ppm, commonly taken as a baseline for levels before 1950. Comparison to the well-known 800,000 year old Dome C ice core is also performed. The best-performing climate change models and observational analysis are seen to project more warming than the average model often relied upon. World atmosphere, temperature, and sea level trends for 2100 and beyond are analyzed. A laboratory experiment proves the dramatic heat-entrapment capability of CO2 compared to pure air, which yields insights into the future global atmospheric system. Policy-relevant climate remediation, including gigaton carbon capture, zero and negative emissions and positive individual action, are reviewed and updated, with recommendations.

Global Environmental Forecast and Roadmap Based on 420 kY of Paleoclimatology

As the world’s population has tripled(3x)since 1950,with another 50%increase expected by 2100,global annual carbon dioxide emissions growth rate has quadrupled(4x)since 1950 and global energy demand has quintupled(5x),all in the same time period.This discontinuous combination can be called a“3-4-5 Triad”and the sudden acceleration in all three arenas is too stressful on the environment and the damaging effects will be felt globally for centuries to come unless drastic action is taken.More importantly,the energy demand at 5x is outstripping the other two.This clearly means that as the population explodes at 3x,the emerging middle class wants almost twice as much as their usual share as fossil-fueled generators spread around the globe and modern conveniences become more and more desirable.However,such energy demand at 5x is an artificial human need that is predicted by RMI.org to result in four to five billion new window-mounted air conditioners by 2050 that will add even more to the global warming caused by increasing atmospheric carbon.By an examination of paleoclimatology for the past 420,000 years,it is demonstrable that reducing the concentration of this single most prolific heat-trapping gas by geoengineering back to pre-industrial levels of less than 300 ppm can actually give humankind a collective control over the world’s rapidly rising average global temperature and once more,a temperate climate to live in.

NON-LINEAR DYNAMIC BEHAVIOR OF THERMOELASTIC CIRCULAR PLATE WITH VARYING THICKNESS SUBJECTED TO NONCONSERVATIVE LOADING

The non-linear dynamic behaviors of thermoelastic circular plate with varying thickness subjected to radially uniformly distributed follower forces are considered. Two coupled non-linear differential equations of motion for this problem are derived in terms of the transverse deflection and radial displacement component of the mid-plane of the plate. Using the Kantorovich averaging method, the differential equation of mode shape of the plate is derived, and the eigenvalue problem is solved by using shooting method. The eigencurves for frequencies and critical loads of the circular plate with unmovable simply supported edge and clamped edge are obtained. The effects of the variation of thickness and temperature on the frequencies and critical loads of the thermoelastic circular plate subjected to radially uniformly distributed follower forces are then discussed.