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1
Sobel, Adam, Shuguang Wang, and Daehyun Kim. "Moist Static Energy Budget of the MJO during DYNAMO." Journal of the Atmospheric Sciences 71, no. 11 (October 29, 2014): 4276–91. http://dx.doi.org/10.1175/jas-d-14-0052.1.
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Abstract The authors analyze the column-integrated moist static energy budget over the region of the tropical Indian Ocean covered by the sounding array during the Cooperative Indian Ocean Experiment on Intraseasonal Variability in the Year 2011 (CINDY2011)/Dynamics of the Madden–Julian Oscillation (DYNAMO) field experiment in late 2011. The analysis is performed using data from the sounding array complemented by additional observational datasets for surface turbulent fluxes and atmospheric radiative heating. The entire analysis is repeated using the ECMWF Interim Re-Analysis (ERA-Interim). The roles of surface turbulent fluxes, radiative heating, and advection are quantified for the two MJO events that occurred in October and November using the sounding data; a third event in December is also studied in the ERA-Interim data. These results are consistent with the view that the MJO’s moist static energy anomalies grow and are sustained to a significant extent by the radiative feedbacks associated with MJO water vapor and cloud anomalies and that propagation of the MJO is associated with advection of moist static energy. Both horizontal and vertical advection appear to play significant roles in the events studied here. Horizontal advection strongly moistens the atmosphere during the buildup to the active phase of the October event when the low-level winds switch from westerly to easterly. Horizontal advection strongly dries the atmosphere in the wake of the active phases of the November and December events as the westerlies associated with off-equatorial cyclonic gyres bring subtropical dry air into the convective region from the west and north. Vertical advection provides relative moistening ahead of the active phase and drying behind it, associated with an increase of the normalized gross moist stability.
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Adames, Ángel F., Rosa M. Vargas Martes, Haochang Luo, and Richard B. Rood. "Moist Static Potential Vorticity Budget in Tropical Motion Systems." Journal of the Atmospheric Sciences 79, no. 3 (March 2022): 763–79. http://dx.doi.org/10.1175/jas-d-21-0161.1.
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Abstract Analyses of simple models of moist tropical motion systems reveal that the column-mean moist static potential vorticity (MSPV) can explain their propagation and growth. The MSPV is akin to the equivalent PV except it uses moist static energy (MSE) instead of the equivalent potential temperature. Examination of an MSPV budget that is scaled for moist off-equatorial synoptic-scale systems reveals that α, the ratio between the vertical gradients of latent and dry static energies, describes the relative contribution of dry and moist advective processes to the evolution of MSPV. Horizontal advection of the moist component of MSPV, a process akin to horizontal MSE advection, governs the evolution of synoptic-scale systems in regions of high humidity. On the other hand, horizontal advection of dry PV predominates in a dry atmosphere. Derivation of a “moist static” wave activity density budget reveals that α also describes the relative importance of moist and dry processes to wave activity amplification and decay. Linear regression analysis of the MSPV budget in eastern Pacific easterly waves shows that the MSPV anomalies originate over the eastern Caribbean and propagate westward due to dry PV advection. They are amplified by the fluxes of the moist component of MSPV over the Caribbean Sea and over the eastern Pacific from 105° to 130°W, underscoring the importance of moist processes in these waves. On the other hand, dry PV convergence amplifies the waves from 90° to 100°W, likely as a result of the barotropic energy conversions that occur in this region.
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Yu, Lijun, Shuhui Wu, and Zhanhong Ma. "Evaluation of Moist Static Energy in a Simulated Tropical Cyclone." Atmosphere 10, no. 6 (June 12, 2019): 319. http://dx.doi.org/10.3390/atmos10060319.
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The characteristics of moist static energy (MSE) and its budget in a simulated tropical cyclone (TC) are examined in this study. Results demonstrate that MSE in a TC system is enhanced as the storm strengthens, primarily because of two mechanisms: upward transfer of surface heat fluxes and subsequent warming of the upper troposphere. An inspection of the interchangeable approximation between MSE and equivalent potential temperature (θe) suggests that although MSE is capable of capturing overall structures of θe, some important features will still be distorted, specifically the low-MSE pool outside the eyewall. In this low-MSE region, from the budget analysis, the discharge of MSE in the boundary layer may even surpass the recharge of MSE from the ocean. Unlike the volume-averaged MSE, the mass-weighted MSE in a fixed volume following the TC shows no apparent increase as the TC intensifies, because the atmosphere becomes continually thinner accompanying the warming of the storm. By calculating a mass-weighted volume MSE budget, the TC system is found to export MSE throughout its lifetime, since the radial outflow overwhelms the radial inflow. Moreover, the more intensified the TC is, the more export of MSE there tends to be. The input of MSE by surface heat fluxes is roughly balanced by the combined effects of radiation and lateral export, wherein a great majority of the imported MSE is reduced by radiation, while the export of MSE from the TC system to the environment accounts for only a small portion.
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Neelin, J. David, and Isaac M. Held. "Modeling Tropical Convergence Based on the Moist Static Energy Budget." Monthly Weather Review 115, no. 1 (January 1987): 3–12. http://dx.doi.org/10.1175/1520-0493(1987)115<0003:mtcbot>2.0.co;2.
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Overland, James E., Philip Turet, and Abraham H. Oort. "Regional Variations of Moist Static Energy Flux into the Arctic." Journal of Climate 9, no. 1 (January 1996): 54–65. http://dx.doi.org/10.1175/1520-0442(1996)009<0054:rvomse>2.0.co;2.
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Skific, Natasa, and Jennifer A. Francis. "Drivers of projected change in arctic moist static energy transport." Journal of Geophysical Research: Atmospheres 118, no. 7 (April 4, 2013): 2748–61. http://dx.doi.org/10.1002/jgrd.50292.
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Frierson, Dargan M. W., Isaac M. Held, and Pablo Zurita-Gotor. "A Gray-Radiation Aquaplanet Moist GCM. Part II: Energy Transports in Altered Climates." Journal of the Atmospheric Sciences 64, no. 5 (May 1, 2007): 1680–93. http://dx.doi.org/10.1175/jas3913.1.
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Abstract A simplified moist general circulation model is used to study changes in the meridional transport of moist static energy by the atmosphere as the water vapor content is increased. The key assumptions of the model are gray radiation, with water vapor and other constituents having no effect on radiative transfer, and mixed layer aquaplanet boundary conditions, implying that the atmospheric meridional energy transport balances the net radiation at the top of the atmosphere. These simplifications allow the authors to isolate the effect of moisture on energy transports by baroclinic eddies in a relatively simple setting. The authors investigate the partition of moist static energy transport in the model into dry static energy and latent energy transports as water vapor concentrations are increased, by varying a constant in the Clausius–Clapeyron relation. The increase in the poleward moisture flux is rather precisely compensated by a reduction in the dry static energy flux. These results are interpreted with diffusive energy balance models (EBMs). The simplest of these is an analytic model that has the property of exact invariance of total energy flux as the moisture content is changed, but the assumptions underlying this model are not accurately satisfied by the GCM. A more complex EBM that includes expressions for the diffusivity, length scale, velocity scale, and latitude of maximum baroclinic eddy activity provides a better fit to the GCM’s behavior.
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Shaw, Tiffany A., Pragallva Barpanda, and Aaron Donohoe. "A Moist Static Energy Framework for Zonal-Mean Storm-Track Intensity." Journal of the Atmospheric Sciences 75, no. 6 (May 30, 2018): 1979–94. http://dx.doi.org/10.1175/jas-d-17-0183.1.
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Abstract A moist static energy (MSE) framework for zonal-mean storm-track intensity, defined as the extremum of zonal-mean transient eddy MSE flux, is derived and applied across a range of time scales. According to the framework, storm-track intensity can be decomposed into contributions from net energy input [sum of shortwave absorption and surface heat fluxes into the atmosphere minus outgoing longwave radiation (OLR) and atmospheric storage] integrated poleward of the storm-track position and MSE flux by the mean meridional circulation or stationary eddies at the storm-track position. The framework predicts storm-track decay in spring and amplification in fall in response to seasonal insolation. When applied diagnostically the framework shows shortwave absorption and land turbulent surface heat fluxes account for the seasonal evolution of Northern Hemisphere (NH) intensity; however, they are partially compensated by OLR (Planck feedback) and stationary eddy MSE flux. The negligible amplitude of Southern Hemisphere (SH) seasonal intensity is consistent with the compensation of shortwave absorption by OLR and oceanic turbulent surface heat fluxes (ocean energy storage). On interannual time scales, El Niño minus La Niña conditions amplify the NH storm track, consistent with decreased subtropical stationary eddy MSE flux. Finally, on centennial time scales, the CO2 indirect effect (sea surface temperature warming) amplifies the NH summertime storm track whereas the direct effect (increased CO2 over land) weakens it, consistent with opposing turbulent surface heat flux responses over land and ocean.
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Yasunaga, Kazuaki, Satoru Yokoi, Kuniaki Inoue, and Brian E. Mapes. "Space–Time Spectral Analysis of the Moist Static Energy Budget Equation." Journal of Climate 32, no. 2 (December 28, 2018): 501–29. http://dx.doi.org/10.1175/jcli-d-18-0334.1.
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Abstract The budget of column-integrated moist static energy (MSE) is examined in wavenumber–frequency transforms of longitude–time sections over the tropical belt. Cross-spectra with satellite-derived precipitation (TRMM-3B42) are used to emphasize precipitation-coherent signals in reanalysis [ERA-Interim (ERAI)] estimates of each term in the budget equation. Results reveal different budget balances in convectively coupled equatorial waves (CCEWs) as well as in the Madden–Julian oscillation (MJO) and tropical depression (TD)-type disturbances. The real component (expressing amplification or damping of amplitude) for horizontal advection is modest for most wave types but substantially damps the MJO. Its imaginary component is hugely positive (it acts to advance phase) in TD-type disturbances and is positive for MJO and equatorial Rossby (ERn1) wave disturbances (almost negligible for the other CCEWs). The real component of vertical advection is negatively correlated (damping effect) with precipitation with a magnitude of approximately 10% of total latent heat release for all disturbances except for TD-type disturbance. This effect is overestimated by a factor of 2 or more if advection is computed using the time–zonal mean MSE, suggesting that nonlinear correlations between ascent and humidity would be positive (amplification effect). ERAI-estimated radiative heating has a positive real part, reinforcing precipitation-correlated MSE excursions. The magnitude is up to 14% of latent heating for the MJO and much less for other waves. ERAI-estimated surface flux has a small effect but acts to amplify MJO and ERn1 waves. The imaginary component of budget residuals is large and systematically positive, suggesting that the reanalysis model’s physical MSE sources would not act to propagate the precipitation-associated MSE anomalies properly.
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Hannah, Walter M., and Eric D. Maloney. "The moist static energy budget in NCAR CAM5 hindcasts during DYNAMO." Journal of Advances in Modeling Earth Systems 6, no. 2 (May 27, 2014): 420–40. http://dx.doi.org/10.1002/2013ms000272.
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Merlis, Timothy M., and Matthew Henry. "Simple Estimates of Polar Amplification in Moist Diffusive Energy Balance Models." Journal of Climate 31, no. 15 (August 2018): 5811–24. http://dx.doi.org/10.1175/jcli-d-17-0578.1.
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Diffusive energy balance models (EBMs) that use moist static energy, rather than temperature, as the thermodynamic variable to determine the energy transport provide an idealized framework to understand the pattern of radiatively forced surface warming. These models have a polar amplified warming pattern that is quantitatively similar to general circulation model simulations. Even without surface albedo changes or other spatially varying feedbacks, they simulate polar amplification that results from increased poleward energy transport with warming. Here, two estimates for polar amplification are presented that do not require numerical solution of the EBM governing equation. They are evaluated relative to the results of numerical moist EBM solutions. One estimate considers only changes in a moist thermodynamic quantity (assuming that the increase in energy transport results in a spatially uniform change in moist static energy in the warmed climate) and has more polar amplification than the EBM solution. The other estimate uses a new solution of a truncated form of the moist EBM equation, which allows for a temperature change that is consistent with both the dry and latent energy transport changes, as well as radiative changes. The truncated EBM solution provides an estimate for polar amplification that is nearly identical to that of the numerical EBM solution and only depends on the EBM parameters and climatology of temperature. This solution sheds light on the dependence of polar amplification on the climatological temperature distribution and offers an estimate of the residual polar warming in solar radiation management geoengineered climates.
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Privé, Nikki C., and R. Alan Plumb. "Monsoon Dynamics with Interactive Forcing. Part II: Impact of Eddies and Asymmetric Geometries." Journal of the Atmospheric Sciences 64, no. 5 (May 1, 2007): 1431–42. http://dx.doi.org/10.1175/jas3917.1.
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Abstract The roles of eddies and forcing asymmetry in the dynamics of the large-scale monsoon circulation are investigated with a general circulation model. The net impact of eddies is found to be a slight weakening of the zonal mean monsoon circulation. The eddies strongly impact the momentum budget of the circulation, but the qualitative behavior of the monsoon flow is not substantially altered. The introduction of asymmetric forcing reveals the limitations of axisymmetric studies in representing the fully three-dimensional monsoon. Advection of low subcloud moist static energy air from the midlatitude oceans is seen to strongly impact the subcloud moist static energy budget in the continental subtropics, limiting the poleward extent of the monsoon. The advection of low moist static energy air must be blocked by orography, or the source of low moist static energy air must be removed, in order to induce strong precipitation over the subtropical landmass. An equatorial SST gradient is needed to induce a cross-equatorial meridional monsoon circulation. The location of the maximum subcloud moist static energy remains a good indicator for the limit of the monsoon.
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Annamalai, H. "ENSO Precipitation Anomalies along the Equatorial Pacific: Moist Static Energy Framework Diagnostics." Journal of Climate 33, no. 21 (November 1, 2020): 9103–27. http://dx.doi.org/10.1175/jcli-d-19-0374.1.
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AbstractWith the recognition that equatorial Pacific precipitation anomalies are fundamental to global teleconnections during ENSO winters, the present research applies vertically integrated moist static energy (MSE) budget analysis to historical simulations of CMIP5 models. Process-based assessment is carried out to understand if the models capture the differing processes that account for regional precipitation anomalies along the equatorial Pacific and to isolate a few leading processes that account for the diversified precipitation response to similar SST forcing and vice versa. To assess SST biases in CMIP5, analysis is also carried out in AMIP5 solutions. Diagnostics reveal that models have limitations in representing the “sign” of MSE sources and sinks and, even if they do, compensating errors dominate the budget. The diverse response in precipitation depends on model parameterizations that determine anomalous net radiative flux divergence in the column, free troposphere moisture, and MSE export out of the column, although these processes are not independent. Diagnostics derived from AMIP5 solutions support the findings from CMIP5. The implication is that biases in representing any one of these processes are expected to imprint on others, acknowledging the tight connections among moisture, convection, and radiation. CMIP5 models have limitations in representing the basic states in SST and precipitation over the Niño-3.4 region, and the different convective regimes over the equatorial central and eastern Pacific regions with implications for ENSO. Study limitations are that MSE sources/sinks depend on parameterizations and their interactions, making it difficult to isolate one particular process for attribution. Budgets estimated from monthly anomalies do not capture contributions from high-frequency variability that are vital in closing the budgets.
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Pauluis, Olivier. "Sources and Sinks of Available Potential Energy in a Moist Atmosphere." Journal of the Atmospheric Sciences 64, no. 7 (July 1, 2007): 2627–41. http://dx.doi.org/10.1175/jas3937.1.
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Abstract Available potential energy (APE) is defined as the difference between the total static energy of the atmosphere and that of a reference state that minimizes the total static energy after a sequence of reversible adiabatic transformations. Determining the rate at which APE is generated in the atmosphere allows one to estimate the amount of kinetic energy that can be generated by atmosphere flows. Previous expressions for the sources and sinks of APE rely on a dry framework and are limited by the fact that they require prior knowledge of the distribution of latent heat release by atmospheric motion. In contrast, this paper uses a moist APE framework to derive a general formula for the sources and sinks of APE that can be equally applied to dry and moist circulations. Two key problems are addressed here. First, it is shown that any reorganization of the reference state due to diabatic heating or addition of water does not change its total static energy. This property makes it possible to determine the rate of change in APE even in the absence of an analytic formula for the reference state, as is the case in a moist atmosphere. Second, the effects of changing the total water content of an air parcel are also considered in order to evaluate the changes of APE due to precipitation, evaporation, and diffusion of water vapor. Based on these new findings, one can obtain the rate of change of APE from that of atmospheric entropy, water content, and pressure. This result is used to determine the sources and sinks of APE due to different processes such as external energy sources, frictional dissipation, diffusion of sensible heat and water vapor, surface evaporation, precipitation, and reevaporation. These sources and sinks are then discussed in the context of an idealized atmosphere in radiative–convective equilibrium. For a moist atmosphere, the production of APE by the surface energy flux is much larger than any observational or theoretical estimates of frictional dissipation, and, as is argued here, must be balanced by a comparable sink of APE due to the diffusion of water vapor from unstable to stable air parcels.
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Wing, Allison A., Suzana J. Camargo, Adam H. Sobel, Daehyun Kim, Yumin Moon, Hiroyuki Murakami, Kevin A. Reed, et al. "Moist Static Energy Budget Analysis of Tropical Cyclone Intensification in High-Resolution Climate Models." Journal of Climate 32, no. 18 (August 20, 2019): 6071–95. http://dx.doi.org/10.1175/jcli-d-18-0599.1.
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Abstract Tropical cyclone intensification processes are explored in six high-resolution climate models. The analysis framework employs process-oriented diagnostics that focus on how convection, moisture, clouds, and related processes are coupled. These diagnostics include budgets of column moist static energy and the spatial variance of column moist static energy, where the column integral is performed between fixed pressure levels. The latter allows for the quantification of the different feedback processes responsible for the amplification of moist static energy anomalies associated with the organization of convection and cyclone spinup, including surface flux feedbacks and cloud-radiative feedbacks. Tropical cyclones (TCs) are tracked in the climate model simulations and the analysis is applied along the individual tracks and composited over many TCs. Two methods of compositing are employed: a composite over all TC snapshots in a given intensity range, and a composite over all TC snapshots at the same stage in the TC life cycle (same time relative to the time of lifetime maximum intensity for each storm). The radiative feedback contributes to TC development in all models, especially in storms of weaker intensity or earlier stages of development. Notably, the surface flux feedback is stronger in models that simulate more intense TCs. This indicates that the representation of the interaction between spatially varying surface fluxes and the developing TC is responsible for at least part of the intermodel spread in TC simulation.
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Huang, Wei, J. W. Bao, Xu Zhang, and Baode Chen. "Comparison of the Vertical Distributions of Cloud Properties from Idealized Extratropical Deep Convection Simulations Using Various Horizontal Resolutions." Monthly Weather Review 146, no. 3 (March 1, 2018): 833–51. http://dx.doi.org/10.1175/mwr-d-17-0162.1.
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ABSTRACT The authors coarse-grained and analyzed the output from a large-eddy simulation (LES) of an idealized extratropical supercell storm using the Weather Research and Forecasting (WRF) Model with various horizontal resolutions (200 m, 400 m, 1 km, and 3 km). The coarse-grained physical properties of the simulated convection were compared with explicit WRF simulations of the same storm at the same resolution of coarse-graining. The differences between the explicit simulations and the coarse-grained LES output increased as the horizontal grid spacing in the explicit simulation coarsened. The vertical transport of the moist static energy and total hydrometeor mixing ratio in the explicit simulations converged to the LES solution at the 200-m grid spacing. Based on the analysis of the coarse-grained subgrid vertical flux of the moist static energy, the authors confirmed that the nondimensional subgrid vertical flux of the moist static energy varied with the subgrid fractional cloudiness according to a function of fractional cloudiness, regardless of the box size. The subgrid mass flux could not account for most of the total subgrid vertical flux of the moist static energy because the eddy-transport component associated with the internal structural inhomogeneity of convective clouds was of a comparable magnitude. This study highlights the ongoing challenge in developing scale-aware parameterizations of subgrid convection.
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Srinivasan, J., and G. L. Smith. "The Role of Heat Fluxes and Moist Static Energy in Tropical Convergence Zones." Monthly Weather Review 124, no. 10 (October 1996): 2089–99. http://dx.doi.org/10.1175/1520-0493(1996)124<2089:trohfa>2.0.co;2.
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Yano, Jun-Ichi, and Maarten H. P. Ambaum. "Moist static energy: definition, reference constants, a conservation law and effects on buoyancy." Quarterly Journal of the Royal Meteorological Society 143, no. 708 (October 2017): 2727–34. http://dx.doi.org/10.1002/qj.3121.
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Masunaga, Hirohiko, and Tristan S. L’Ecuyer. "A Mechanism of Tropical Convection Inferred from Observed Variability in the Moist Static Energy Budget." Journal of the Atmospheric Sciences 71, no. 10 (September 22, 2014): 3747–66. http://dx.doi.org/10.1175/jas-d-14-0015.1.
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Abstract Temporal variability in the moist static energy (MSE) budget is studied with measurements from a combination of different satellites including the Tropical Rainfall Measuring Mission (TRMM) and A-Train platforms. A composite time series before and after the development of moist convection is obtained from the observations to delineate the evolution of MSE and moisture convergences and, in their combination, gross moist stability (GMS). A new algorithm is then applied to estimate large-scale vertical motion from energy budget constraints through vertical-mode decomposition into first and second baroclinic modes and a background shallow mode. The findings are indicative of a possible mechanism of tropical convection. A gradual destabilization is brought about by the MSE convergence intrinsic to the positive second baroclinic mode (congestus mode) that increasingly counteracts a weak MSE divergence in the background state. GMS is driven to nearly zero as the first baroclinic mode begins to intensify, accelerating the growth of vigorous large-scale updrafts and deep convection. As the convective burst peaks, the positive second mode switches to the negative mode (stratiform mode) and introduces an abrupt rise in MSE divergence that likely discourages further maintenance of deep convection. The first mode quickly dissipates and GMS increases away from zero, eventually returning to the background shallow-mode state. A notable caveat to this scenario is that GMS serves as a more reliable metric when defined with a radiative heating rate included to offset MSE convergence.
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Ma, Zhanhong, Jianfang Fei, Xiaogang Huang, and Xiaoping Cheng. "A Potential Problem with the Application of Moist Static Energy in Tropical Cyclone Studies." Journal of the Atmospheric Sciences 72, no. 8 (August 1, 2015): 3009–19. http://dx.doi.org/10.1175/jas-d-14-0367.1.
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Abstract The moist static energy (MSE) is derived from the first law of thermodynamics and has been widely used in tropical cyclone (TC) studies because of its energetic and conventionally recognized conservation properties. This study investigates the validation of the MSE application in TC systems based on cloud-resolving numerical simulations. By examining the approximations made in deriving the MSE, neglecting the horizontal advection of pressure (namely, the generation of kinetic energy) relative to the vertical advection of pressure is found to be in error in the boundary layer of TCs with the horizontal advection of pressure even being several times larger than the vertical advection of pressure near the surface. Such a problematic approximation has broken down the conservation property of MSE in adiabatic conditions. An investigation of the energetic characteristics based on an MSE budget equation demonstrates that the MSE has created significant bias in evaluating the energy transport in the inner region of the TC boundary layer. Neglecting the kinetic energy conversion term in the boundary layer leads to a more strengthened cool-pool feature of MSE relative to the equivalent potential temperature; therefore, the interchangeable relationship between these two terms may also be inaccurate in the boundary layer. It is concluded that, although the MSE is an instrumental term for TC studies, caution should be taken when it is used in the boundary layer of TCs.
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Feng, Tao, Jia-Yuh Yu, Xiu-Qun Yang, and Ronghui Huang. "Convective Coupling in Tropical-Depression-Type Waves. Part II: Moisture and Moist Static Energy Budgets." Journal of the Atmospheric Sciences 77, no. 10 (October 1, 2020): 3423–40. http://dx.doi.org/10.1175/jas-d-19-0173.1.
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AbstractThe companion of this paper, Part I, discovered the characteristics of the rainfall progression in tropical-depression (TD)-type waves over the western North Pacific. In Part II, the large-scale controls on the convective rainfall progression have been investigated using the ERA-Interim data and the TRMM 3B42 precipitation-rate data during June–October from 1998 to 2013 through budgets of moist static energy (MSE) and moisture. A buildup of column-integrated MSE occurs in advance of deep convection, and an export of MSE occurs following deep convection, which is consistent with the MSE recharge–discharge paradigm. The MSE recharge–discharge is controlled by horizontal processes, whereby horizontal moisture advection causes net MSE import prior to deep convection. Such moistening by horizontal advection creates a moist midtroposphere, which helps destabilize the atmospheric column, leading to the development of deep convective rainfall. Following the heaviest rainfall, negative horizontal moisture advection dries the troposphere, inhibiting convection. Such moistening and drying processes explain why deep convection can develop without preceding shallow convection. The advection of moisture anomalies by the mean horizontal flow controls the tropospheric moistening and drying processes. As the TD-type waves propagate northwestward in coincidence with the northwestward environmental flow, the moisture, or convective rainfall, is phase locked to the waves. The critical role of the MSE import by horizontal advection in modulating the rainfall progression is supported by the anomalous gross moist stability (AGMS), where the lowest AGMS corresponds to the quickest increase in the precipitation rate prior to the rainfall maximum.
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Inoue, Kuniaki, and Larissa Back. "Column-Integrated Moist Static Energy Budget Analysis on Various Time Scales during TOGA COARE." Journal of the Atmospheric Sciences 72, no. 5 (May 1, 2015): 1856–71. http://dx.doi.org/10.1175/jas-d-14-0249.1.
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Abstract Moist static energy (MSE) budgets on different time scales are analyzed in the TOGA COARE data using Lanczos filters to separate variability with different frequencies. Four different time scales (~2-day, ~5-day, ~10-day, and MJO time scales) are chosen based on the power spectrum of the precipitation and previous TOGA COARE studies. The lag regression-slope technique is utilized to depict characteristic patterns of the variability associated with the MSE budgets on the different time scales. This analysis illustrates that the MSE budgets behave in significantly different ways on the different time scales. On shorter time scales, the vertical advection acts as a primary driver of the recharge–discharge mechanism of column MSE. As the time scale gets longer, in contrast, the relative contributions of the other budget terms become greater, and consequently, on the MJO time scale all the budget terms have nearly the same amplitude. Specifically, these results indicate that horizontal advection plays an important role in the eastward propagation of the MJO during TOGA COARE. On the MJO time scale, the export of MSE by the vertical advection is in phase with the precipitation. On shorter time scales, the vertical velocity profile transitions from bottom heavy to top heavy, while on longer time scales, the shape becomes more constant and similar to a first-baroclinic-mode structure. This leads to a more-constant gross moist stability on longer time scales, which the authors estimate.
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de Szoeke, Simon P. "Variations of the Moist Static Energy Budget of the Tropical Indian Ocean Atmospheric Boundary Layer." Journal of the Atmospheric Sciences 75, no. 5 (May 2018): 1545–51. http://dx.doi.org/10.1175/jas-d-17-0345.1.
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The atmospheric circulation depends on poorly understood interactions between the tropical atmospheric boundary layer (BL) and convection. The surface moist static energy (MSE) source (130 W m−2, of which 120 W m−2 is evaporation) to the tropical marine BL is balanced by upward MSE flux at the BL top that is the source for deep convection. Important for modeling tropical convection and circulation is whether MSE enters the free troposphere by dry turbulent processes originating within the boundary layer or by motions generated by moist deep convection in the free troposphere. Here, highly resolved observations of the BL quantify the MSE fluxes in approximate agreement with recent cloud-resolving models, but the fluxes depend on convective conditions. In convectively suppressed (weak precipitation) conditions, entrainment and downdraft fluxes export equal shares (60 W m−2) of MSE from the BL. Downdraft fluxes are found to increase 50%, and entrainment to decrease, under strongly convective conditions. Variable entrainment and downdraft MSE fluxes between the BL and convective clouds must both be considered for modeling the climate.
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PATTANAIK, D. R. "Analysis of moist convective instability over Indian monsoon region and neighbourhood." MAUSAM 54, no. 3 (January 18, 2022): 659–70. http://dx.doi.org/10.54302/mausam.v54i3.1557.
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The nature of deep convection over the Indian monsoon region and neighbourhood during different seasons is investigated by analysing Dry Static Energy (DSE), Moist Static Energy (MSE), Precipitable Water Content (PWC) and Convective Available Potential Energy (CAPE) computed from 13 years (1982-1994) monthly mean data obtained from the National Centre for Environmental Prediction (NCEP) reanalysis.
It is seen from this study that the mean atmosphere over the Indian monsoon region is convectively unstable at lower levels during all seasons with highest degree of instability and maximum PWC during the monsoon season compared to other seasons. The results also show that during the monsoon season from June to September the convectively most unstable region is situated over the Head Bay of Bengal (HBOB) region and decreases gradually from West Pacific (WP), Equatorial South Indian Ocean (ESIO) and to Arabian Sea (AS) regions. Similarly the CAPE value is also highest over HBOB region and it is about 362 Joules/kg (24%) more than the CAPE value over WP region. The composite MSE profiles for strong and weak monsoon years indicate higher values of MSE at all levels during the strong monsoon years compared to weak monsoon years. It is also observed that the surface MSE and PWC over Indian monsoon region during June to September show significant positive correlation with All India Summer Monsoon Rainfall (AISMR).
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Liao, Xueyu, Tim Li, and Chen Ma. "Moist Static Energy and Secondary Circulation Evolution Characteristics during the Rapid Intensification of Super Typhoon Yutu (2007)." Atmosphere 13, no. 7 (July 13, 2022): 1105. http://dx.doi.org/10.3390/atmos13071105.
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A high-resolution Weather Research and Forecasting (WRF) model is used to simulate inner-core thermodynamic (such as moist static energy) and dynamic secondary circulation structure evolutions associated with the rapid intensification (RI) of Super Typhoon Yutu (2007). The results show that the column-integrated moist static energy (MSE) and the secondary circulation strength are significantly correlated to the typhoon intensity change. A rapid increase of the MSE during the RI period is primarily attributed to inner core temperature increase, due to enhanced subsidence within the eye and strengthened convective heating along the eyewall. The column-integrated MSE budget analysis shows that its rapid increase during the RI is mainly caused by surface latent heat flux. A further diagnosis of the Sawyer–Eliassen equation shows that the rapid strengthening of the secondary circulation during RI results from both the radially expanding positive diabatic heating over the eyewall and the occurrence of a second heating center outside the eyewall. While the radially expanding eyewall heating contributes about 70% of the secondary circulation change, the outer heating contributes about 30%.
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Kuang, Zhiming. "The Wavelength Dependence of the Gross Moist Stability and the Scale Selection in the Instability of Column-Integrated Moist Static Energy." Journal of the Atmospheric Sciences 68, no. 1 (January 1, 2011): 61–74. http://dx.doi.org/10.1175/2010jas3591.1.
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Abstract Gross moist stability (GMS), a measure of how efficiently divergent flow exports column-integrated moist static energy (MSE), is a widely used quantity in current simplified models of the tropical mean circulation and intraseasonal variabilities such as the Madden–Julian oscillation (MJO), where it is often assumed to be constant. In this paper, it is shown, with cloud-system-resolving model experiments that incorporate feedback from the large-scale flow, that the GMS is smaller at longer wavelengths. The reason for this wavelength dependence is that temperature anomalies required to maintain a given divergent flow increase with wavelength. At long wavelengths, the required temperature anomalies become sufficiently strong to affect the shape of convective heating. As a consequence, the divergent flow is forced to be less top heavy in order to maintain the balance of momentum, heat, and moisture, as well as consistency with the behavior of cumulus convection. A simple model is constructed to illustrate this behavior. Given the ongoing theoretical efforts that view the MJO as resulting from instability in column-integrated MSE, the results presented here provide a planetary-scale selection for such instability, which is absent in current theoretical models that assume a constant GMS.
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Adames, Ángel F., and Yi Ming. "Moisture and Moist Static Energy Budgets of South Asian Monsoon Low Pressure Systems in GFDL AM4.0." Journal of the Atmospheric Sciences 75, no. 6 (June 1, 2018): 2107–23. http://dx.doi.org/10.1175/jas-d-17-0309.1.
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Abstract The mechanisms that lead to the propagation of anomalous moisture and moist static energy (MSE) in monsoon low and high pressure systems, collectively referred to as synoptic-scale monsoonal disturbances (SMDs), are investigated using daily output fields from GFDL’s atmospheric general circulation model, version 4.0 (AM4.0). On the basis of linear regression analysis of westward-propagating rainfall anomalies of time scales shorter than 15 days, it is found that SMDs are organized into wave trains of three to four individual cyclones and anticyclones. These events amplify over the Bay of Bengal, reach a maximum amplitude over the eastern coast of India, and dissipate as they approach the Arabian Sea. The structure and propagation of the simulated SMDs resemble those documented in observations. It is found that moisture and MSE anomalies exhibit similar horizontal structures in the simulated SMDs, indicating that moisture is the leading contributor to MSE. Propagation of the moisture anomalies is governed by vertical moisture advection, while the MSE anomalies propagate because of horizontal advection of dry static energy by the anomalous winds. By combining the budgets, we interpret the propagation of the moisture anomalies in terms of lifting that is forced by horizontal dry static energy advection, that is, ascent along sloping isentropes. This process moistens the lower free troposphere, producing an environment that is more favorable to deep convection. Ascent driven by radiative heating is of primary importance to the maintenance of the moisture anomalies.
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Döös, Kristofer, and Johan Nilsson. "Analysis of the Meridional Energy Transport by Atmospheric Overturning Circulations." Journal of the Atmospheric Sciences 68, no. 8 (August 1, 2011): 1806–20. http://dx.doi.org/10.1175/2010jas3493.1.
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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.
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Haertel, Patrick T., George N. Kiladis, Andrew Denno, and Thomas M. Rickenbach. "Vertical-Mode Decompositions of 2-Day Waves and the Madden–Julian Oscillation." Journal of the Atmospheric Sciences 65, no. 3 (March 1, 2008): 813–33. http://dx.doi.org/10.1175/2007jas2314.1.
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Abstract Vertical structures of 2-day waves and the Madden–Julian oscillation (MJO) are projected onto vertical normal modes for a quiescent tropical troposphere. Three modes capture the gross tropospheric structure of 2-day waves, while only two modes are needed to represent most of the baroclinic structure of the MJO. Deep circulations that project onto the first baroclinic mode are associated with deep cumulonimbus and stratiform rainfall. Shallow circulations that project onto higher wavenumber modes are associated with precipitating shallow cumulus and congestus and stratiform rainfall. For both disturbances the horizontal divergence contributed by shallow modes is an important factor in the column-integrated moist enthalpy budget. These modes converge moist static energy for a time prior to when deep circulations export moist static energy. These results highlight the importance of properly representing the effects of shallow cumulus, congestus, and stratiform precipitation in theories of convectively coupled waves and in atmospheric models.
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Wu, Xiaoqing, and Liping Deng. "Comparison of Moist Static Energy and Budget between the GCM-Simulated Madden–Julian Oscillation and Observations over the Indian Ocean and Western Pacific." Journal of Climate 26, no. 14 (July 12, 2013): 4981–93. http://dx.doi.org/10.1175/jcli-d-12-00607.1.
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Abstract The moist static energy (MSE) anomalies and MSE budget associated with the Madden–Julian oscillation (MJO) simulated in the Iowa State University General Circulation Model (ISUGCM) over the Indian and Pacific Oceans are compared with observations. Different phase relationships between MJO 850-hPa zonal wind, precipitation, and surface latent heat flux are simulated over the Indian Ocean and western Pacific, which are greatly influenced by the convection closure, trigger conditions, and convective momentum transport (CMT). The moist static energy builds up from the lower troposphere 15–20 days before the peak of MJO precipitation, and reaches the maximum in the middle troposphere (500–600 hPa) near the peak of MJO precipitation. The gradual lower-tropospheric heating and moistening and the upward transport of moist static energy are important aspects of MJO events, which are documented in observational studies but poorly simulated in most GCMs. The trigger conditions for deep convection, obtained from the year-long cloud-resolving model (CRM) simulations, contribute to the striking difference between ISUGCM simulations with the original and modified convection schemes and play the major role in the improved MJO simulation in ISUGCM. Additionally, the budget analysis with the ISUGCM simulations shows the increase in MJO MSE is in phase with the horizontal advection of MSE over the western Pacific, while out of phase with the horizontal advection of MSE over the Indian Ocean. However, the NCEP analysis shows that the tendency of MJO MSE is in phase with the horizontal advection of MSE over both oceans.
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Frierson, Dargan M. W., Isaac M. Held, and Pablo Zurita-Gotor. "A Gray-Radiation Aquaplanet Moist GCM. Part I: Static Stability and Eddy Scale." Journal of the Atmospheric Sciences 63, no. 10 (October 1, 2006): 2548–66. http://dx.doi.org/10.1175/jas3753.1.
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Abstract In this paper, a simplified moist general circulation model is developed and used to study changes in the atmospheric general circulation as the water vapor content of the atmosphere is altered. The key elements of the model physics are gray radiative transfer, in which water vapor and other constituents have no effect on radiative fluxes, a simple diffusive boundary layer with prognostic depth, and a mixed layer aquaplanet surface boundary condition. This GCM can be integrated stably without a convection parameterization, with large-scale condensation only, and this study focuses on this simplest version of the model. These simplifications provide a useful framework in which to focus on the interplay between latent heat release and large-scale dynamics. In this paper, the authors study the role of moisture in determining the tropospheric static stability and midlatitude eddy scale. In a companion paper, the effects of moisture on energy transports by baroclinic eddies are discussed. The authors vary a parameter in the Clausius–Clapeyron relation to control the amount of water in the atmosphere, and consider circulations ranging from the dry limit to 10 times a control value. The typical length scale of midlatitude eddies is found to be remarkably insensitive to the amount of moisture in the atmosphere in this model. The Rhines scale evaluated at the latitude of the maximum eddy kinetic energy fits the model results for the eddy scale well. Moist convection is important in determining the extratropical lapse rate, and the dry stability is significantly increased with increased moisture content.
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Hu, Feng, and Tim Li. "Effect of vertical overturning circulation scale and moist static energy tendency on MJO phase speed." Atmospheric and Oceanic Science Letters 15, no. 1 (January 2022): 100150. http://dx.doi.org/10.1016/j.aosl.2022.100150.
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Cai, Qiongqiong, Guang J. Zhang, and Tianjun Zhou. "Impacts of Shallow Convection on MJO Simulation: A Moist Static Energy and Moisture Budget Analysis." Journal of Climate 26, no. 8 (April 15, 2013): 2417–31. http://dx.doi.org/10.1175/jcli-d-12-00127.1.
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Abstract The role of shallow convection in Madden–Julian oscillation (MJO) simulation is examined in terms of the moist static energy (MSE) and moisture budgets. Two experiments are carried out using the NCAR Community Atmosphere Model, version 3.0 (CAM3.0): a “CTL” run and an “NSC” run that is the same as the CTL except with shallow convection disabled below 700 hPa between 20°S and 20°N. Although the major features in the mean state of outgoing longwave radiation, 850-hPa winds, and vertical structure of specific humidity are reasonably reproduced in both simulations, moisture and clouds are more confined to the planetary boundary layer in the NSC run. While the CTL run gives a better simulation of the MJO life cycle when compared with the reanalysis data, the NSC shows a substantially weaker MJO signal. Both the reanalysis data and simulations show a recharge–discharge mechanism in the MSE evolution that is dominated by the moisture anomalies. However, in the NSC the development of MSE and moisture anomalies is weaker and confined to a shallow layer at the developing phases, which may prevent further development of deep convection. By conducting the budget analysis on both the MSE and moisture, it is found that the major biases in the NSC run are largely attributed to the vertical and horizontal advection. Without shallow convection, the lack of gradual deepening of upward motion during the developing stage of MJO prevents the lower troposphere above the boundary layer from being preconditioned for deep convection.
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Maloney, Eric D. "The Moist Static Energy Budget of a Composite Tropical Intraseasonal Oscillation in a Climate Model." Journal of Climate 22, no. 3 (February 1, 2009): 711–29. http://dx.doi.org/10.1175/2008jcli2542.1.
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Abstract The intraseasonal moist static energy (MSE) budget is analyzed in a climate model that produces realistic eastward-propagating tropical intraseasonal wind and precipitation variability. Consistent with the recharge–discharge paradigm for tropical intraseasonal variability, a buildup of column-integrated MSE occurs within low-level easterly anomalies in advance of intraseasonal precipitation, and a discharge of MSE occurs during and after precipitation when westerly anomalies occur. The strongest MSE anomalies peak in the lower troposphere and are, primarily, regulated by specific humidity anomalies. The leading terms in the column-integrated intraseasonal MSE budget are horizontal advection and surface latent heat flux, where latent heat flux is dominated by the wind-driven component. Horizontal advection causes recharge (discharge) of MSE within regions of anomalous equatorial lower-tropospheric easterly (westerly) anomalies, with the meridional component of the moisture advection dominating the MSE budget near 850 hPa. Latent heat flux anomalies oppose the MSE tendency due to horizontal advection, making the recharge and discharge of column MSE more gradual than if horizontal advection were acting alone. This relationship has consequences for the time scale of intraseasonal variability in the model. Eddies dominate intraseasonal meridional moisture advection in the model. During periods of low-level intraseasonal easterly anomalies, eddy kinetic energy (EKE) is anomalously low due to a suppression of tropical synoptic-scale disturbances and other variability on time scales shorter than 20 days. Anomalous moistening of the equatorial lower troposphere occurs during intraseasonal easterly periods through suppression of eddy moisture advection between the equator and poleward latitudes. During intraseasonal westerly periods, EKE is enhanced, leading to anomalous drying of the equatorial lower troposphere through meridional advection. Given the importance of meridional moisture advection and wind-induced latent heat flux to the intraseasonal MSE budget, these findings suggest that to simulate realistic intraseasonal variability, climate models must have realistic basic-state distributions of lower-tropospheric zonal wind and specific humidity.
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Wang, Lu, and Tim Li. "Effect of vertical moist static energy advection on MJO eastward propagation: sensitivity to analysis domain." Climate Dynamics 54, no. 3-4 (January 20, 2020): 2029–39. http://dx.doi.org/10.1007/s00382-019-05101-8.
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Smyth, Jane E., and Yi Ming. "Characterizing Drying in the South American Monsoon Onset Season with the Moist Static Energy Budget." Journal of Climate 33, no. 22 (November 15, 2020): 9735–48. http://dx.doi.org/10.1175/jcli-d-20-0217.1.
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AbstractThe tropical atmospheric circulation and attendant rainfall exhibit seasonally dependent responses to increasing temperatures. Understanding changes in the South American monsoon system is of particular interest given the sensitivity of the southern Amazon rainforest to changes in dry season length. We utilize the latest Geophysical Fluid Dynamics Laboratory Atmospheric Model (GFDL AM4) to analyze the response of the South American monsoon to uniform sea surface temperature (SST) warming. SST warming is a poorly understood yet impactful component of greenhouse gas–induced climate change. Region-mean rainfall declines by 11%, and net precipitation (precipitation minus evaporation) declines by 40%, during the monsoon onset season (September–November), producing a more severe dry season. The column-integrated moist static energy (MSE) budget helps elucidate the physical mechanisms of the simulated drying. Based on the seasonal analysis, precipitation reductions tend to occur when 1) a convecting region’s climatological MSE export is dominated by horizontal rather than vertical advection, and 2) the horizontal MSE advection increases in the perturbed climate, impeding ascent. On a synoptic scale, the South American low-level jet strengthens and exports more moisture from the monsoon sector, exacerbating spring drying.
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Kjellsson, Joakim, Kristofer Döös, Frédéric B. Laliberté, and Jan D. Zika. "The Atmospheric General Circulation in Thermodynamical Coordinates." Journal of the Atmospheric Sciences 71, no. 3 (February 27, 2014): 916–28. http://dx.doi.org/10.1175/jas-d-13-0173.1.
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Abstract The zonal and meridional components of the atmospheric general circulation are used to define a global thermodynamic streamfunction in dry static energy versus latent heat coordinates. Diabatic motions in the tropical circulations and fluxes driven by midlatitude eddies are found to form a single, global thermodynamic cycle. Calculations based on the Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) dataset indicate that the cycle has a peak transport of 428 Sv (Sv ≡ 109 kg s−1). The thermodynamic cycle encapsulates a globally interconnected heat and water cycle comprising ascent of moist air where latent heat is converted into dry static energy, radiative cooling where dry air loses dry static energy, and a moistening branch where air is warmed and moistened. It approximately follows a tropical moist adiabat and is bounded by the Clausius–Clapeyron relationship for near-surface air. The variability of the atmospheric general circulation is related to ENSO events using reanalysis data from recent years (1979–2009) and historical simulations from the EC-Earth Consortium (EC-Earth) coupled climate model (1850–2005). The thermodynamic cycle in both EC-Earth and ERA-Interim widens and weakens with positive ENSO phases and narrows and strengthens during negative ENSO phases with a high correlation coefficient. Weakening in amplitude suggests a weakening of the large-scale circulation, while widening suggests an increase in mean tropical near-surface moist static energy.
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Sumi, Yukari, and Hirohiko Masunaga. "A Moist Static Energy Budget Analysis of Quasi-2-Day Waves Using Satellite and Reanalysis Data." Journal of the Atmospheric Sciences 73, no. 2 (February 1, 2016): 743–59. http://dx.doi.org/10.1175/jas-d-15-0098.1.
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Abstract A moist static energy (MSE) budget analysis is applied to quasi-2-day waves to examine the effects of thermodynamic processes on the wave propagation mechanism. The 2-day waves are defined as westward inertia–gravity (WIG) modes identified with filtered geostationary infrared measurements, and the thermodynamic parameters and MSE budget variables computed from reanalysis data are composited with respect to the WIG peaks. The composite horizontal and vertical MSE structures are overall as theoretically expected from WIG wave dynamics. A prominent horizontal MSE advection is found to exist, although the wave dynamics is mainly regulated by vertical advection. The vertical advection decreases MSE around the times of the convective peak, plausibly resulting from the first baroclinic mode associated with deep convection. Normalized gross moist stability (NGMS) is used to examine the thermodynamic processes involving the large-scale dynamics and convective heating. NGMS gradually decreases to zero before deep convection and reaches a maximum after the convection peak, where low (high) NGMS leads (lags) deep convection. The decrease in NGMS toward zero before the occurrence of active convection suggests an increasingly efficient conversion from convective heating to large-scale dynamics as the wave comes in, while the increase afterward signifies that this linkage swiftly dies out after the peak.
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Hill, Spencer A., Yi Ming, Isaac M. Held, and Ming Zhao. "A Moist Static Energy Budget–Based Analysis of the Sahel Rainfall Response to Uniform Oceanic Warming." Journal of Climate 30, no. 15 (August 2017): 5637–60. http://dx.doi.org/10.1175/jcli-d-16-0785.1.
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Climate models generate a wide range of precipitation responses to global warming in the African Sahel, but all that use the NOAA Geophysical Fluid Dynamics Laboratory AM2.1 model as their atmospheric component dry the region sharply. This study compares the Sahel’s wet season response to uniform 2-K SST warming in AM2.1 using either its default convective parameterization, relaxed Arakawa–Schubert (RAS), or an alternate, the University of Washington (UW) parameterization, using the moist static energy (MSE) budget to diagnose the relevant mechanisms. UW generates a drier, cooler control Sahel climate than does RAS and a modest rainfall increase with SST warming rather than a sharp decrease. Horizontal advection of dry, low-MSE air from the Sahara Desert—a leading-order term in the control MSE budget with either parameterization—is enhanced with oceanic warming, driven by enhanced meridional MSE and moisture gradients spanning the Sahel. With RAS, this occurs throughout the free troposphere and is balanced by anomalous MSE import through anomalous subsidence, which must be especially large in the midtroposphere where the moist static stability is small. With UW, the strengthening of the meridional MSE gradient is mostly confined to the lower troposphere, due in part to comparatively shallow prevailing convection. This necessitates less subsidence, enabling convective and total precipitation to increase with UW, although both large-scale precipitation and precipitation minus evaporation decrease. This broad set of hydrological and energetic responses persists in simulations with SSTs varied over a wide range.
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Inoue, Kuniaki, and Larissa E. Back. "Gross Moist Stability Assessment during TOGA COARE: Various Interpretations of Gross Moist Stability." Journal of the Atmospheric Sciences 72, no. 11 (November 1, 2015): 4148–66. http://dx.doi.org/10.1175/jas-d-15-0092.1.
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Abstract Daily averaged TOGA COARE data are analyzed to investigate the convective amplification/decay mechanisms. The gross moist stability (GMS), which represents moist static energy (MSE) export efficiency by large-scale circulations associated with the convection, is studied together with two quantities, called the critical GMS (a ratio of diabatic forcing to the convective intensity) and the drying efficiency [a version of the effective GMS (GMS minus critical GMS)]. The analyses reveal that convection intensifies (decays) via negative (positive) drying efficiency. The authors illustrate that variability of the drying efficiency during the convective amplifying phase is predominantly explained by the vertical MSE advection (or vertical GMS), which imports MSE via bottom-heavy vertical velocity profiles (associated with negative vertical GMS) and eventually starts exporting MSE via top-heavy profiles (associated with positive vertical GMS). The variability of the drying efficiency during the decaying phase is, in contrast, explained by the horizontal MSE advection. The critical GMS, which is moistening efficiency due to the diabatic forcing, is broadly constant throughout the convective life cycle, indicating that the diabatic forcing always tends to destabilize the convective system in a constant manner. The authors propose various ways of computing quasi-time-independent “characteristic GMS” and demonstrate that all of them are equivalent and can be interpreted as (i) the critical GMS, (ii) the GMS at the maximum precipitation, and (iii) a combination of feedback constants between the radiation, evaporation, and convection. Those interpretations indicate that each convective life cycle is a fluctuation of rapidly changing GMS around slowly changing characteristic GMS.
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Ma, Guanguo, Zhenjiao Sun, Hui Ma, and Pengcheng Li. "Calibration of Contact Parameters for Moist Bulk of Shotcrete Based on EDEM." Advances in Materials Science and Engineering 2022 (March 17, 2022): 1–14. http://dx.doi.org/10.1155/2022/6072303.
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To obtain the contact parameters of the moist bulk of shotcrete accurately and quickly, this study calibrated the contact parameters of the moist bulk of shotcrete by physical stacking test and simulation method. Based on the Hertz–Mindlin with JKR (Johnon–Kendall–Roberts) model, the discrete element simulation is carried out. Using P-BD to screen seven initial parameters, it is found that JKR surface energy, rolling friction coefficient between particles and restitution coefficient of particle impact have significant effects on the angle of repose of the moist bulk of shotcrete. According to B-BD, the second-order regression model of angle of repose and significance parameters was established. Three significant parameters were obtained: JKR surface energy 0.418 J/m2, rolling friction coefficient 0.06 and static friction coefficient 1. The angle of repose obtained by simulation is compared with the physical test value, and the relative error is 1.88%. The results show that the calibration method proposed in this study can accurately simulate the physical stacking test, and can provide a reference for the calibration of contact parameters of the moist bulk of shotcrete.
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Ren, Pengfei, Daehyun Kim, Min-Seop Ahn, Daehyun Kang, and Hong-Li Ren. "Intercomparison of MJO Column Moist Static Energy and Water Vapor Budget among Six Modern Reanalysis Products." Journal of Climate 34, no. 8 (April 2021): 2977–3001. http://dx.doi.org/10.1175/jcli-d-20-0653.1.
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AbstractThis study conducts an intercomparison of the column-integrated moist static energy (MSE) and water vapor budget of the Madden–Julian oscillation (MJO) among six modern global reanalysis products (RAs). Inter-RA differences in the mean MSE, MJO MSE anomalies, individual MSE budget terms, and their relative contributions to the propagation and maintenance of MJO MSE anomalies are examined. Also investigated is the relationship between the MJO column water vapor (CWV) budget residuals with the other CWV budget terms as well as with the two parameters that characterize cloud–radiation feedback and moisture–convection coupling. Results show a noticeable inter-RA spread in the mean-state MSE, especially its vertical structure. In all RAs, horizontal MSE advection dominates the propagation of the MJO MSE while column-integrated longwave radiative heating and vertical MSE advection are found to be the key processes for MJO maintenance. The MSE budget terms directly affected by the model parameterization schemes exhibit high uncertainty. The differences in anomalous vertical velocity mainly contribute to the large differences in vertical MSE advection among the RAs. The budget residuals show large inter-RA differences and have nonnegligible contributions to MJO maintenance and propagation in most RAs. RAs that underestimate (overestimate) the strength of cloud–radiation feedback and the convective moisture adjustment time scale tend to have positive (negative) MJO CWV budget residual, indicating the critical role of these processes in the maintenance of MJO CWV anomalies. Our results emphasize that a correct representation of the interactions among moisture, convection, cloud, and radiation is the key for an accurate depiction of the MJO MSE and CWV budget in RAs.
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Wang, Zeyi, Xiaolong Chen, and Tianjun Zhou. "The onset and seasonal march of East Asian summer monsoon from perspective of moist static energy." Chinese Science Bulletin 66, no. 28-29 (January 18, 2021): 3744–56. http://dx.doi.org/10.1360/tb-2020-1236.
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Andersen, Joseph Allan, and Zhiming Kuang. "Moist Static Energy Budget of MJO-like Disturbances in the Atmosphere of a Zonally Symmetric Aquaplanet." Journal of Climate 25, no. 8 (April 10, 2012): 2782–804. http://dx.doi.org/10.1175/jcli-d-11-00168.1.
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Abstract A Madden–Julian oscillation (MJO)-like spectral feature is observed in the time–space spectra of precipitation and column-integrated moist static energy (MSE) for a zonally symmetric aquaplanet simulated with Superparameterized Community Atmospheric Model (SPCAM). This disturbance possesses the basic structural and propagation features of the observed MJO. To explore the processes involved in propagation and maintenance of this disturbance, this study analyzes the MSE budget of the disturbance. The authors observe that the disturbances propagate both eastward and poleward. The column-integrated longwave heating is the only significant source of column-integrated MSE acting to maintain the MJO-like anomaly balanced against the combination of column-integrated horizontal and vertical advection of MSE and latent heat flux. Eastward propagation of the MJO-like disturbance is associated with MSE generated by both column integrated horizontal and vertical advection of MSE, with the column longwave heating generating MSE that retards the propagation. The contribution to the eastward propagation by the column-integrated horizontal advection of MSE is dominated by synoptic eddies. Further decomposition indicates that the advection contribution to the eastward propagation is dominated by meridional advection of MSE by anomalous synoptic eddies caused by the suppression of eddy activity ahead of the MJO convection. This suppression is linked to the barotropic conversion mechanism, with the gradients of the low-frequency wind experienced by the synoptic eddies within the MJO envelope acting to modulate the eddy kinetic energy. The meridional eddy advection’s contribution to poleward propagation is dominated by the mean state’s (meridionally varying) eddy activity acting on the anomalous MSE gradients associated with the MJO.
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Bui, Hien Xuan, Jia-Yuh Yu, and Chia Chou. "Impacts of Vertical Structure of Large-Scale Vertical Motion in Tropical Climate: Moist Static Energy Framework." Journal of the Atmospheric Sciences 73, no. 11 (October 20, 2016): 4427–37. http://dx.doi.org/10.1175/jas-d-16-0031.1.
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Abstract Interactions between cumulus convection and its large-scale environment have been recognized as crucial to the understanding of tropical climate and its variability. In this study, the moist static energy (MSE) budget is employed to investigate the potential impact of the vertical structure of large-scale vertical motion in tropical climate based on results from both reanalysis data and model simulation. Two domains are selected over the western and eastern Pacific with vertical motion profiles that are dominated by top-heavy and bottom-heavy structures, respectively. The bottom-heavy structure is climatologically associated with more shallow convection, while the top-heavy structure is related to more deep convection. The column-integrated vertical MSE advection of top-heavy vertical motion is positive, while that of bottom-heavy vertical motion tends to be negative. Controlling factors responsible for the above vertical MSE advection contrast are discussed based on a simple decomposition of the MSE budget equation. It was found that the sign of vertical MSE advection is determined mainly by the vertical moisture transport, the magnitude of which is very sensitive to the structure of vertical motion. A top-heavy (bottom heavy) structure of vertical motion favors an export (import) of MSE and a positive (negative) value of the vertical MSE advection.
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Beucler, Tom, Tristan H. Abbott, Timothy W. Cronin, and Michael S. Pritchard. "Comparing Convective Self‐Aggregation in Idealized Models to Observed Moist Static Energy Variability Near the Equator." Geophysical Research Letters 46, no. 17-18 (September 2019): 10589–98. http://dx.doi.org/10.1029/2019gl084130.
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DeMott, Charlotte A., James J. Benedict, Nicholas P. Klingaman, Steven J. Woolnough, and David A. Randall. "Diagnosing ocean feedbacks to the MJO: SST-modulated surface fluxes and the moist static energy budget." Journal of Geophysical Research: Atmospheres 121, no. 14 (July 27, 2016): 8350–73. http://dx.doi.org/10.1002/2016jd025098.
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Bretherton, Christopher S., Peter N. Blossey, and Marat Khairoutdinov. "An Energy-Balance Analysis of Deep Convective Self-Aggregation above Uniform SST." Journal of the Atmospheric Sciences 62, no. 12 (December 1, 2005): 4273–92. http://dx.doi.org/10.1175/jas3614.1.
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Abstract The spatial organization of deep moist convection in radiative–convective equilibrium over a constant sea surface temperature is studied. A 100-day simulation is performed with a three-dimensional cloud-resolving model over a (576 km)2 domain with no ambient rotation and no mean wind. The convection self-aggregates within 10 days into quasi-stationary mesoscale patches of dry, subsiding and moist, rainy air columns. The patches ultimately merge into a single intensely convecting moist patch surrounded by a broad region of very dry subsiding air. The self-aggregation is analyzed as an instability of a horizontally homogeneous convecting atmosphere driven by convection–water vapor–radiation feedbacks that systematically dry the drier air columns and moisten the moister air columns. Column-integrated heat, water, and moist static energy budgets over (72 km)2 horizontal blocks show that this instability is primarily initiated by the reduced radiative cooling of air columns in which there is extensive anvil cirrus, augmented by enhanced surface latent and sensible heat fluxes under convectively active regions due to storm-induced gustiness. Mesoscale circulations intensify the later stages of self-aggregation by fluxing moist static energy from the dry to the moist regions. A simple mathematical model of the initial phase of self-aggregation is proposed based on the simulations. In accordance with this model, the self-aggregation can be suppressed by horizontally homogenizing the radiative cooling or surface fluxes. Lower-tropospheric wind shear leads to slightly slower and less pronounced self-aggregation into bands aligned along the shear vector. Self-aggregation is sensitive to the ice microphysical parameterization, which affects the location and extent of cirrus clouds and their radiative forcing. Self-aggregation is also sensitive to ambient Coriolis parameter f, and can induce spontaneous tropical cyclogenesis for large f. Inclusion of an interactive mixed-layer ocean slows but does not prevent self-aggregation.
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ALAM, M. D. MAHBUB, and SULTANA SHAFEE. "Analysis of different tropospheric energies in the surroundings of the Bay of Bengal during different cyclonic periods." MAUSAM 48, no. 3 (November 24, 2021): 367–74. http://dx.doi.org/10.54302/mausam.v48i3.4263.
Full textAbstract:
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.
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Barpanda, Pragallva, and Tiffany Shaw. "Using the Moist Static Energy Budget to Understand Storm-Track Shifts across a Range of Time Scales." Journal of the Atmospheric Sciences 74, no. 8 (July 21, 2017): 2427–46. http://dx.doi.org/10.1175/jas-d-17-0022.1.
Full textAbstract:
Abstract Storm tracks shift meridionally in response to forcing across a range of time scales. Here the authors formulate a moist static energy (MSE) framework for storm-track position and use it to understand storm-track shifts in response to seasonal insolation, El Niño minus La Niña conditions, and direct (increased CO2 over land) and indirect (increased sea surface temperature) effects of increased CO2. Two methods (linearized Taylor series and imposed MSE flux divergence) are developed to quantify storm-track shifts and decompose them into contributions from net energy (MSE input to the atmosphere minus atmospheric storage) and MSE flux divergence by the mean meridional circulation and stationary eddies. Net energy is not a dominant contribution across the time scales considered. The stationary eddy contribution dominates the storm-track shift in response to seasonal insolation, El Niño minus La Niña conditions, and CO2 direct effect in the Northern Hemisphere, whereas the mean meridional circulation contribution dominates the shift in response to CO2 indirect effect during northern winter and in the Southern Hemisphere during May and October. Overall, the MSE framework shows the seasonal storm-track shift in the Northern Hemisphere is connected to the stationary eddy MSE flux evolution. Furthermore, the equatorward storm-track shift during northern winter in response to El Niño minus La Niña conditions involves a different regime than the poleward shift in response to increased CO2 even though the tropical upper troposphere warms in both cases.