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1
JIANG, QINGFANG. "Moist dynamics and orographic precipitation." Tellus A 55, no. 4 (August 2003): 301–16. http://dx.doi.org/10.1034/j.1600-0870.2003.00025.x.
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Jiang, Qingfang. "Moist dynamics and orographic precipitation." Tellus A: Dynamic Meteorology and Oceanography 55, no. 4 (January 2003): 301–16. http://dx.doi.org/10.3402/tellusa.v55i4.14577.
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Palotai, Csaba, Shawn Brueshaber, Ramanakumar Sankar, and Kunio Sayanagi. "Moist Convection in the Giant Planet Atmospheres." Remote Sensing 15, no. 1 (December 30, 2022): 219. http://dx.doi.org/10.3390/rs15010219.
Повний текст джерелаАнотація:
The outer planets of our Solar System display a myriad of interesting cloud features, of different colors and sizes. The differences between the types of observed clouds suggest a complex interplay between the dynamics and chemistry at play in these atmospheres. Particularly, the stark difference between the banded structures of Jupiter and Saturn vs. the sporadic clouds on the ice giants highlights the varieties in dynamic, chemical and thermal processes that shape these atmospheres. Since the early explorations of these planets by spacecrafts, such as Voyager and Voyager 2, there are many outstanding questions about the long-term stability of the observed features. One hypothesis is that the internal heat generated during the formation of these planets is transported to the upper atmosphere through latent heat release from convecting clouds (i.e., moist convection). In this review, we present evidence of moist convective activity in the gas giant atmospheres of our Solar System from remote sensing data, both from ground- and space-based observations. We detail the processes that drive moist convective activity, both in terms of the dynamics as well as the microphysical processes that shape the resulting clouds. Finally, we also discuss the effects of moist convection on shaping the large-scale dynamics (such as jet structures on these planets).
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Hunter, Maria O., Michael Keller, Douglas Morton, Bruce Cook, Michael Lefsky, Mark Ducey, Scott Saleska, Raimundo Cosme de Oliveira, and Juliana Schietti. "Structural Dynamics of Tropical Moist Forest Gaps." PLOS ONE 10, no. 7 (July 13, 2015): e0132144. http://dx.doi.org/10.1371/journal.pone.0132144.
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MAJDA, ANDREW J., YULONG XING, and MAJID MOHAMMADIAN. "Moist multi-scale models for the hurricane embryo." Journal of Fluid Mechanics 657 (June 30, 2010): 478–501. http://dx.doi.org/10.1017/s0022112010001515.
Повний текст джерелаАнотація:
Determining the finite-amplitude preconditioned states in the hurricane embryo, which lead to tropical cyclogenesis, is a central issue in contemporary meteorology. In the embryo there is competition between different preconditioning mechanisms involving hydrodynamics and moist thermodynamics, which can lead to cyclogenesis. Here systematic asymptotic methods from applied mathematics are utilized to develop new simplified moist multi-scale models starting from the moist anelastic equations. Three interesting multi-scale models emerge in the analysis. The balanced mesoscale vortex (BMV) dynamics and the microscale balanced hot tower (BHT) dynamics involve simplified balanced equations without gravity waves for vertical vorticity amplification due to moist heat sources and incorporate nonlinear advective fluxes across scales. The BMV model is the central one for tropical cyclogenesis in the embryo. The moist mesoscale wave (MMW) dynamics involves simplified equations for mesoscale moisture fluctuations, as well as linear hydrostatic waves driven by heat sources from moisture and eddy flux divergences. A simplified cloud physics model for deep convection is introduced here and used to study moist axisymmetric plumes in the BHT model. A simple application in periodic geometry involving the effects of mesoscale vertical shear and moist microscale hot towers on vortex amplification is developed here to illustrate features of the coupled multi-scale models. These results illustrate the use of these models in isolating key mechanisms in the embryo in a simplified content.
6
Prasanna, V., and H. Annamalai. "Moist Dynamics of Extended Monsoon Breaks over South Asia." Journal of Climate 25, no. 11 (June 2012): 3810–31. http://dx.doi.org/10.1175/jcli-d-11-00459.1.
Повний текст джерелаАнотація:
In the present research to identify moist processes that initiate and maintain extended monsoon breaks over South Asia moisture and moist static energy (MSE) budgets are performed on the newly available European Centre for Medium-Range Weather Forecasts Interim reanalysis (ERA-Interim) and ensemble integrations from a coupled model. The hypothesis that interaction between moist physics and regional circulation and the role of cloud–radiation feedbacks are important is tested. Budget diagnostics show that dry advection is the principal moist process to initiate extended breaks. Its sources are (i) regional anticyclonic circulation anomalies forced by equatorial Indian Ocean negative rainfall anomalies advect low MSE air from north to central India, and (ii) rainfall enhancement over tropical west Pacific forces cyclonic circulation anomalies to its northwest as a Rossby wave response, and the northerlies at the poleward flank of this circulation advect air of low MSE content from north. The dominance of anomalous wind acting on climatological moisture gradient is confirmed from an examination of the moisture advection equation. A partition of various flux terms indicates that over central India, due to an increase in upwelling shortwave and longwave fluxes, radiative cooling increases during extended breaks. Here, enhanced rainfall over the equatorial Indian Ocean promotes anomalous radiative warming due to trapping of upwelling fluxes. The differential radiative heating anchors a local Hadley circulation with descent over central India. A direct implication of this research is that observational efforts are necessary to monitor the three-dimensional moisture distribution and cloud–radiation interaction over the monsoon region that would aid in better understanding, modeling, and predicting extended monsoon breaks.
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Straus, David M., and Mary Ann Huntley. "Interactions between Moist Heating and Dynamics in Atmospheric Predictability." Journal of the Atmospheric Sciences 51, no. 3 (February 1994): 447–64. http://dx.doi.org/10.1175/1520-0469(1994)051<0447:ibmhad>2.0.co;2.
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Biello, Joseph A., and Andrew J. Majda. "Intraseasonal multi-scale moist dynamics of the tropical atmosphere." Communications in Mathematical Sciences 8, no. 2 (2010): 519–40. http://dx.doi.org/10.4310/cms.2010.v8.n2.a11.
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Thatcher, Diana R., and Christiane Jablonowski. "A moist aquaplanet variant of the Held–Suarez test for atmospheric model dynamical cores." Geoscientific Model Development 9, no. 4 (April 4, 2016): 1263–92. http://dx.doi.org/10.5194/gmd-9-1263-2016.
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Abstract. A moist idealized test case (MITC) for atmospheric model dynamical cores is presented. The MITC is based on the Held–Suarez (HS) test that was developed for dry simulations on “a flat Earth” and replaces the full physical parameterization package with a Newtonian temperature relaxation and Rayleigh damping of the low-level winds. This new variant of the HS test includes moisture and thereby sheds light on the nonlinear dynamics–physics moisture feedbacks without the complexity of full-physics parameterization packages. In particular, it adds simplified moist processes to the HS forcing to model large-scale condensation, boundary-layer mixing, and the exchange of latent and sensible heat between the atmospheric surface and an ocean-covered planet. Using a variety of dynamical cores of the National Center for Atmospheric Research (NCAR)'s Community Atmosphere Model (CAM), this paper demonstrates that the inclusion of the moist idealized physics package leads to climatic states that closely resemble aquaplanet simulations with complex physical parameterizations. This establishes that the MITC approach generates reasonable atmospheric circulations and can be used for a broad range of scientific investigations. This paper provides examples of two application areas. First, the test case reveals the characteristics of the physics–dynamics coupling technique and reproduces coupling issues seen in full-physics simulations. In particular, it is shown that sudden adjustments of the prognostic fields due to moist physics tendencies can trigger undesirable large-scale gravity waves, which can be remedied by a more gradual application of the physical forcing. Second, the moist idealized test case can be used to intercompare dynamical cores. These examples demonstrate the versatility of the MITC approach and suggestions are made for further application areas. The new moist variant of the HS test can be considered a test case of intermediate complexity.
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Thatcher, D. R., and C. Jablonowski. "A moist aquaplanet variant of the Held–Suarez test for atmospheric model dynamical cores." Geoscientific Model Development Discussions 8, no. 9 (September 29, 2015): 8263–340. http://dx.doi.org/10.5194/gmdd-8-8263-2015.
Повний текст джерелаАнотація:
Abstract. A moist idealized test case (MITC) for atmospheric model dynamical cores is presented. The MITC is based on the Held–Suarez (HS) test that was developed for dry simulations on a flat Earth and replaces the full physical parameterization package with a Newtonian temperature relaxation and Rayleigh damping of the low-level winds. This new variant of the HS test includes moisture and thereby sheds light on the non-linear dynamics-physics moisture feedbacks without the complexity of full physics parameterization packages. In particular, it adds simplified moist processes to the HS forcing to model large-scale condensation, boundary layer mixing, and the exchange of latent and sensible heat between the atmospheric surface and an ocean-covered planet. Using a variety of dynamical cores of NCAR's Community Atmosphere Model (CAM), this paper demonstrates that the inclusion of the moist idealized physics package leads to climatic states that closely resemble aquaplanet simulations with complex physical parameterizations. This establishes that the MITC approach generates reasonable atmospheric circulations and can be used for a broad range of scientific investigations. This paper provides examples of two application areas. First, the test case reveals the characteristics of the physics-dynamics coupling technique and reproduces coupling issues seen in full-physics simulations. In particular, it is shown that sudden adjustments of the prognostic fields due to moist physics tendencies can trigger undesirable large-scale gravity waves, which can be remedied by a more gradual application of the physical forcing. Second, the moist idealized test case can be used to intercompare dynamical cores. These examples demonstrate the versatility of the MITC approach and suggestions are made for further application areas. The new moist variant of the HS test can be considered a test case of intermediate complexity.
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Nie, Ji, Panxi Dai, and Adam H. Sobel. "Dry and moist dynamics shape regional patterns of extreme precipitation sensitivity." Proceedings of the National Academy of Sciences 117, no. 16 (April 6, 2020): 8757–63. http://dx.doi.org/10.1073/pnas.1913584117.
Повний текст джерелаАнотація:
Responses of extreme precipitation to global warming are of great importance to society and ecosystems. Although observations and climate projections indicate a general intensification of extreme precipitation with warming on global scale, there are significant variations on the regional scale, mainly due to changes in the vertical motion associated with extreme precipitation. Here, we apply quasigeostrophic diagnostics on climate-model simulations to understand the changes in vertical motion, quantifying the roles of dry (large-scale adiabatic flow) and moist (small-scale convection) dynamics in shaping the regional patterns of extreme precipitation sensitivity (EPS). The dry component weakens in the subtropics but strengthens in the middle and high latitudes; the moist component accounts for the positive centers of EPS in the low latitudes and also contributes to the negative centers in the subtropics. A theoretical model depicts a nonlinear relationship between the diabatic heating feedback (α) and precipitable water, indicating high sensitivity of α (thus, EPS) over climatological moist regions. The model also captures the change of α due to competing effects of increases in precipitable water and dry static stability under global warming. Thus, the dry/moist decomposition provides a quantitive and intuitive explanation of the main regional features of EPS.
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Smith, Samuel, Paul W. Staten, and Jian Lu. "How Moist and Dry Intrusions Control the Local Hydrologic Cycle in Present and Future Climates." Journal of Climate 34, no. 11 (June 2021): 4343–59. http://dx.doi.org/10.1175/jcli-d-20-0780.1.
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AbstractModels disagree on how much the hydrologic cycle could intensify under climate change. These changes are expected to scale with the Clausius–Clapeyron relation but may locally diverge due in part to the uncertain response of the general circulation, causing the hydrologic cycle to inherit this uncertainty. To identify how the circulation contributes, we link circulation changes to changes in the higher moments of the hydrologic cycle using the novel dynamical framework of the local hydrologic cycle, the portion of the hydrologic cycle driven by moist or dry intrusions. We expand this dynamical framework, developing a closed budget that diagnoses thermodynamic, advective, and overturning contributions to future hydrologic cycle changes. In analyzing these changes for the Community Earth System Model Large Ensemble, we show that overturning is the main dynamic contributor to the tropical and subtropical annual response, consistent with a weakening of this circulation. In the extratropics, we show that advective contributions, likely from storm track changes, dominate the response. We achieve a cleaner separation between dynamic and thermodynamic contributions through a semiempirical scaling, which reveals the robustness of the Clausius–Clapeyron scaling for the local hydrologic cycle. This scaling also demonstrates the slowing of the local hydrologic cycle and how changing subtropical dynamics asymmetrically impact wave breaking and suppress meridional moisture transport. We conclude that dynamic changes in the subtropics are predominantly responsible for the annual, dynamic response in the extratropics and thus a significant contributor to uncertainty in future projections.
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Castelli, Fabio, Rafael L. Bras, and Kerry A. Emanuel. "An Analytical Approach to the Nonlinear Dynamics of Moist Frontogenesis." Journal of the Atmospheric Sciences 50, no. 11 (June 1993): 1504–18. http://dx.doi.org/10.1175/1520-0469(1993)050<1504:aaattn>2.0.co;2.
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Kurowski, Marcin J., Wojciech W. Grabowski, and Piotr K. Smolarkiewicz. "Anelastic and Compressible Simulation of Moist Dynamics at Planetary Scales." Journal of the Atmospheric Sciences 72, no. 10 (October 1, 2015): 3975–95. http://dx.doi.org/10.1175/jas-d-15-0107.1.
Повний текст джерелаАнотація:
Abstract Moist anelastic and compressible numerical solutions to the planetary baroclinic instability and climate benchmarks are compared. The solutions are obtained by applying a consistent numerical framework for discrete integrations of the various nonhydrostatic flow equations. Moist extension of the baroclinic instability benchmark is formulated as an analog of the dry case. Flow patterns, surface vertical vorticity and pressure, total kinetic energy, power spectra, and total amount of condensed water are analyzed. The climate benchmark extends the baroclinic instability study by addressing long-term statistics of an idealized planetary equilibrium and associated meridional transports. Short-term deterministic anelastic and compressible solutions differ significantly. In particular, anelastic baroclinic eddies propagate faster and develop slower owing to, respectively, modified dispersion relation and abbreviated baroclinic vorticity production. These eddies also carry less kinetic energy, and the onset of their rapid growth occurs later than for the compressible solutions. The observed differences between the two solutions are sensitive to initial conditions as they diminish for large-amplitude excitations of the instability. In particular, on the climatic time scales, the anelastic and compressible solutions evince similar zonally averaged flow patterns with the matching meridional transports of entropy, momentum, and moisture.
15
Chan, Douglas, and Han‐Ru Cho. "The dynamics of moist frontogenesis in a semi‐geostrophic model." Atmosphere-Ocean 29, no. 1 (March 1991): 85–101. http://dx.doi.org/10.1080/07055900.1991.9649394.
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Kravtsov, Sergey, Ilijana Mastilovic, Andrew McC Hogg, William K. Dewar, and Jeffrey R. Blundell. "The Moist Quasi-Geostrophic Coupled Model: MQ-GCM 2.0." Geoscientific Model Development 15, no. 19 (October 7, 2022): 7449–69. http://dx.doi.org/10.5194/gmd-15-7449-2022.
Повний текст джерелаАнотація:
Abstract. This paper contains a description of recent changes to the formulation and numerical implementation of the Quasi-Geostrophic Coupled Model (Q-GCM), which constitute a major update of the previous version of the model (Hogg et al., 2014). The Q-GCM model has been designed to provide an efficient numerical tool to study the dynamics of multi-scale midlatitude air–sea interactions and their climatic impacts. The present additions/alterations were motivated by an inquiry into the dynamics of mesoscale ocean–atmosphere coupling and, in particular, by an apparent lack of the Q-GCM atmosphere's sensitivity to mesoscale sea-surface temperature (SST) anomalies, even at high (mesoscale) atmospheric resolutions, contrary to ample theoretical and observational evidence otherwise. Major modifications aimed at alleviating this problem include an improved radiative-convective scheme resulting in a more realistic model mean state and associated model parameters; a new formulation of entrainment in the atmosphere, which prompts more efficient communication between the atmospheric mixed layer and free troposphere; and an addition of a temperature-dependent wind component in the atmospheric mixed layer and the resulting mesoscale feedbacks. The most drastic change is, however, the inclusion of moist dynamics in the model, which may be key to midlatitude ocean–atmosphere coupling. Accordingly, this version of the model is to be referred to as the MQ-GCM model. Overall, the MQ-GCM model is shown to exhibit a rich spectrum of behaviors reminiscent of many of the observed properties of the Earth's climate system. It remains to be seen whether the added processes are able to affect in fundamental ways the simulated dynamics of the midlatitude ocean–atmosphere system's coupled decadal variability.
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Zhang, Yi, Jian Li, Rucong Yu, Zhuang Liu, Yihui Zhou, Xiaohan Li, and Xiaomeng Huang. "A Multiscale Dynamical Model in a Dry-Mass Coordinate for Weather and Climate Modeling: Moist Dynamics and Its Coupling to Physics." Monthly Weather Review 148, no. 7 (June 15, 2020): 2671–99. http://dx.doi.org/10.1175/mwr-d-19-0305.1.
Повний текст джерелаАнотація:
Abstract A multiscale dynamical model for weather forecasting and climate modeling is developed and evaluated in this study. It extends a previously established layer-averaged, unstructured-mesh nonhydrostatic dynamical core (dycore) to moist dynamics and parameterized physics in a dry-mass vertical coordinate. The dycore and tracer transport components are coupled in a mass-consistent manner, with the dycore providing time-averaged horizontal mass fluxes to passive transport, and tracer transport feeding back to the dycore with updated moisture constraints. The vertical mass flux in the tracer transport is obtained by reevaluating the mass continuity equation to ensure compatibility. A general physics–dynamics coupling workflow is established, and a dycore–tracer–physics splitting strategy is designed to couple these components in a flexible and efficient manner. In this context, two major physics–dynamics coupling strategies are examined. Simple-physics packages from the 2016 Dynamical Core Model Intercomparison Project (DCMIP2016) experimental protocols are used to facilitate the investigation of the model behaviors in idealized moist-physics configurations, including cloud-scale modeling, weather forecasting, and climate modeling, and in a real-world test-case setup. Performance evaluation demonstrates that the model is able to produce reasonable sensitivity and variability at various spatiotemporal scales. The consideration and implications of different physics–dynamics coupling options are discussed within this context. The appendix provides discussion on the energetics in the continuous- and discrete-form equations of motion.
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Kurowski, Marcin J., Wojciech W. Grabowski, and Piotr K. Smolarkiewicz. "Anelastic and Compressible Simulation of Moist Deep Convection." Journal of the Atmospheric Sciences 71, no. 10 (September 22, 2014): 3767–87. http://dx.doi.org/10.1175/jas-d-14-0017.1.
Повний текст джерелаАнотація:
Abstract Anelastic and compressible solutions are compared for two moist deep convection benchmarks, a two-dimensional thermal rising in a saturated moist-neutral deep atmosphere, and a three-dimensional supercell formation. In the anelastic model, the pressure applied in the moist thermodynamics comes from either the environmental hydrostatically balanced pressure profile in the standard anelastic model or is combined with nonhydrostatic perturbations from the elliptic pressure solver in the generalized anelastic model. The compressible model applies either an explicit acoustic-mode-resolving scheme requiring short time steps or a novel implicit scheme allowing time steps as large as those used in the anelastic model. The consistency of the unified numerical framework facilitates direct comparisons of results obtained with anelastic and compressible models. The anelastic and compressible rising thermal solutions agree not only with each other but also with the previously published compressible benchmark solution based on the comprehensive representation of moist dynamics and thermodynamics. In contrast to earlier works focusing on the formulation of moist thermodynamics, the compatibility of the initial conditions is emphasized and its impact on the benchmark solutions is documented. The anelastic and compressible supercell solutions agree well for various versions of anelastic and compressible models even for cloud updrafts reaching 15% of the speed of sound. The nonhydrostatic pressure perturbations turn out to have a negligible impact on the moist dynamics. Numerical and physical details of the simulations, such as the advection scheme, spatial and temporal resolution, or parameters of the subgrid-scale turbulence, have a more significant effect on the solutions than the particular equation system applied.
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Fuhrer, Oliver, and Christoph Schär. "Dynamics of Orographically Triggered Banded Convection in Sheared Moist Orographic Flows." Journal of the Atmospheric Sciences 64, no. 10 (October 1, 2007): 3542–61. http://dx.doi.org/10.1175/jas4024.1.
Повний текст джерелаАнотація:
Abstract Shallow orographic convection embedded in an unstable cap cloud can organize into convective bands. Previous research has highlighted the important role of small-amplitude topographic variations in triggering and organizing banded convection. Here, the underlying dynamical mechanisms are systematically investigated by conducting three-dimensional simulations of moist flows past a two-dimensional mountain ridge using a cloud-resolving numerical model. Most simulations address a sheared environment to account for the observed wind profiles. Results confirm that small-amplitude topographic variations can enhance the development of embedded convection and anchor quasi-stationary convective bands to a fixed location in space. The resulting precipitation patterns exhibit tremendous spatial variability, since regions receiving heavy rainfall can be only kilometers away from regions receiving little or no rain. In addition, the presence of banded convection has important repercussions on the area-mean precipitation amounts. For the experimental setup here, the gravity wave response to small-amplitude topographic variations close to the upstream edge of the cap cloud (which is forced by the larger-scale topography) is found to be the dominant triggering mechanism. Small-scale variations in the underlying topography are found to force the location and spacing of convective bands over a wide range of scales. Further, a self-sufficient mode of unsteady banded convection is investigated that does not dependent on external perturbations and is able to propagate against the mean flow. Finally, the sensitivity of model simulations of banded convection with respect to horizontal computational resolution is investigated. Consistent with predictions from a linear stability analysis, convective bands of increasingly smaller scales are favored as the horizontal resolution is increased. However, small-amplitude topographic roughness is found to trigger banded convection and to control the spacing and location of the resulting bands. Thereby, the robustness of numerical simulations with respect to an increase in horizontal resolution is increased in the presence of topographic variations.
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Arnolds, E. "Dynamics of macrofungi in two moist heathlands in Drenthe, The Netherlands." Acta Botanica Neerlandica 37, no. 2 (June 1988): 291–305. http://dx.doi.org/10.1111/j.1438-8677.1988.tb02137.x.
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Deremble, Bruno, Guillaume Lapeyre, and Michael Ghil. "Atmospheric Dynamics Triggered by an Oceanic SST Front in a Moist Quasigeostrophic Model." Journal of the Atmospheric Sciences 69, no. 5 (May 1, 2012): 1617–32. http://dx.doi.org/10.1175/jas-d-11-0288.1.
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Abstract To understand the atmospheric response to a midlatitude oceanic front, this paper uses a quasigeostrophic (QG) model with moist processes. A well-known, three-level QG model on the sphere has been modified to include such processes in an aquaplanet setting. Its response is analyzed in terms of the upper-level atmospheric jet for sea surface temperature (SST) fronts of different profiles and located at different latitudes. When the SST front is sufficiently strong, it tends to anchor the mean atmospheric jet, suggesting that the jet’s spatial location and pattern are mainly affected by the latitude of the SST front. Changes in the jet’s pattern are studied, focusing on surface sensible heat flux and on moisture effects through latent heat release. It is found that latent heat release due to moist processes is modified when the SST front is changed, and this is responsible for the meridional displacement of the jet. Moreover, both latent heat release and surface sensible heat flux contribute to the jet’s strengthening. These results highlight the role of SST fronts and moist processes in affecting the characteristics of the midlatitude jet stream and of its associated storm track, particularly their positions.
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Fuhrer, Oliver, and Christoph Schär. "Embedded Cellular Convection in Moist Flow past Topography." Journal of the Atmospheric Sciences 62, no. 8 (August 1, 2005): 2810–28. http://dx.doi.org/10.1175/jas3512.1.
Повний текст джерелаАнотація:
Abstract Marginally unstable air masses impinging upon a mountain ridge may lead to the development of a nominally stratiform orographic cloud with shallow embedded convection. Rainfall amounts and distribution are then strongly influenced by the convective dynamics. In this study, the transition from purely stratiform orographic precipitation to flow regimes with embedded convection is systematically investigated. To this end, idealized cloud-resolving numerical simulations of moist flow past a two-dimensional mountain ridge are performed in a three-dimensional domain. A series of simulations with increasing upstream potential instability shows that the convective dynamics may significantly increase precipitation amounts, intensity, and efficiency, to an extent that cannot be replicated by two-dimensional simulations. Under conditions of uniform upstream flow, the embedded convection is of the cellular type. It is demonstrated that simple stability measures of the upstream profile are poor predictors for the occurrence and depth of embedded convection. A linear stability analysis is performed to understand the linear growth of the developing convective instabilities. Embedded convection results if the growth rates of convective instabilities are compatible with the advective time scale (the time an air parcel spends inside the orographic cloud) and the microphysical time scale (time for rain production and fallout). Individual convective updrafts are anchored to the mean flow. Additional simulations serve to demonstrate that the development of embedded convection and associated precipitation may strongly depend on small-amplitude upstream perturbations. Such perturbations enhance the efficacy of the convective circulations and lead to overall stronger precipitation. The potential implications of this result for the predictability of quantitative precipitation are also discussed.
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Joshi, Prakash C., Jeffrey A. Lockwood, N. Vashishth, and A. Singh. "Grasshopper (Orthoptera: Acridoidea) Community Dynamics in a Moist Deciduous Forest in India." Journal of Orthoptera Research, no. 8 (November 1999): 17. http://dx.doi.org/10.2307/3503420.
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Wang, Bin, та Hualan Rui. "Dynamics of the Coupled Moist Kelvin–Rossby Wave on an Equatorialβ-Plane". Journal of the Atmospheric Sciences 47, № 4 (лютий 1990): 397–413. http://dx.doi.org/10.1175/1520-0469(1990)047<0397:dotcmk>2.0.co;2.
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Bishop, Craig H., and Alan J. Thorpe. "Frontal Wave Stability during Moist Deformation Frontogenesis. Part I: Linear Wave Dynamics." Journal of the Atmospheric Sciences 51, no. 6 (March 1994): 852–73. http://dx.doi.org/10.1175/1520-0469(1994)051<0852:fwsdmd>2.0.co;2.
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Dalling, J. W., M. D. Swaine, and Nancy C. Garwood. "Soil seed bank community dynamics in seasonally moist lowland tropical forest, Panama." Journal of Tropical Ecology 13, no. 5 (September 1997): 659–80. http://dx.doi.org/10.1017/s0266467400010853.
Повний текст джерелаАнотація:
ABSTRACTSeasonal changes in the densities of dormant seeds in the soil around eight pioneer trees in the 50-ha Forest Dynamics Plot, on Barro Colorado Island, Panamá were studied, and how seed dispersal and seed dormancy influenced patterns of seed abundance and distribution were examined. Twenty-four, 3-cm-deep soil samples were collected on 30 m transects radiating out from each of the trees in each of four time-intervals through the year, and four 21-cm-deep samples were collected beneath the focal tree crowns. In the surface 0–3 cm of soil, germinable seed densities of all species combined declined from a peak of 1090 seeds m−2 in the mid-wet season in August, to 330 seeds m−2 by the end of the wet season in November. In contrast, at soil depths >3 cm, there was little variation in soil seed bank density through the year. Some variation in soil seed bank density for individual species could be accounted for by distance to reproductive conspecifics. Among species, abundance in the soil was negatively correlated with seed size. Seed persistence varied greatly among species at this site; after 1 y of burial in mesh bags, seed germinability of four species was near zero, while four other species showed no consistent decline in seed germinability after >2 y of burial. For at least one species, Trema micrantha, prolonged seed dormancy was also possible under natural conditions. Twenty-five percent of Trema seeds extracted from the soil at a site occupied by an isolated Trema tree that died between 1982 and 1985 were still germinable in 1994.
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Valappil, Narayanan I., and K. Swarupanandan. "Regeneration dynamics and sylvigenesis in the moist deciduous forests of southwest India." New Forests 11, no. 3 (May 1996): 185–205. http://dx.doi.org/10.1007/bf00036782.
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Kurowski, Marcin J., Wojciech W. Grabowski, and Piotr K. Smolarkiewicz. "Toward Multiscale Simulation of Moist Flows with Soundproof Equations." Journal of the Atmospheric Sciences 70, no. 12 (November 22, 2013): 3995–4011. http://dx.doi.org/10.1175/jas-d-13-024.1.
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Abstract This paper discusses the incorporation of phase changes of the water substance that accompany moist atmospheric flows into the all-scale atmospheric model based on soundproof equations. A specific issue involves developing a theoretical basis and practical implementation to include pressure perturbations associated with atmospheric circulations, from small scale to global, into representations of moist thermodynamics. In small-scale modeling using soundproof equations, pressure perturbations are obtained from the elliptic pressure solver and are typically excluded from the moist thermodynamics. This paper argues that in larger-scale flows, at least the hydrostatic component of the pressure perturbation needs to be included because pressure variation in synoptic weather systems may affect moist thermodynamics in a way comparable to the temperature variations. As an illustration, two idealized test problems are considered: the small-scale moist thermal rising in a stratified environment and the moist mesoscale flow over idealized topography. The paper compares numerical solutions obtained with a fully compressible acoustic mode–resolving model and with two versions of the anelastic model, either including or excluding anelastic pressure perturbations in moist thermodynamics. The two versions of the anelastic model are referred to as the generalized and standard anelastic. In agreement with the scaling arguments, only negligible differences between anelastic and compressible solutions are simulated. Incorporation of the anelastic pressure perturbations into moist thermodynamics paves the way for future studies where larger-scale moist dynamics will be considered.
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Conzemius, Robert J., Richard W. Moore, Michael T. Montgomery, and Christopher A. Davis. "Mesoscale Convective Vortex Formation in a Weakly Sheared Moist Neutral Environment." Journal of the Atmospheric Sciences 64, no. 5 (May 1, 2007): 1443–66. http://dx.doi.org/10.1175/jas3898.1.
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Abstract Idealized simulations of a diabatic Rossby vortex (DRV) in an initially moist neutral baroclinic environment are performed using the fifth-generation National Center for Atmospheric Research–Pennsylvania State University (NCAR–PSU) Mesoscale Model (MM5). The primary objective is to test the hypothesis that the formation and maintenance of midlatitude warm-season mesoscale convective vortices (MCVs) are largely influenced by balanced flow dynamics associated with a vortex that interacts with weak vertical shear. As a part of this objective, the simulated DRV is placed within the context of the Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) field campaign by comparing its tangential velocity, radius of maximum winds, CAPE, and shear with the MCVs observed in BAMEX. The simulations reveal two distinct scales of development. At the larger scale, the most rapidly growing moist baroclinic mode is excited, and exponential growth of this mode occurs during the simulation. Embedded within the large-scale baroclinic wave is a convective system exhibiting the characteristic DRV development, with a positive potential vorticity (PV) anomaly in the lower troposphere and a negative PV anomaly in the upper troposphere, and the positive/negative PV doublet tilted downshear with height. The DRV warm-air advection mechanism is active, and the resulting deep convection helps to reinforce the DRV against the deleterious effects of environmental shear, causing an eastward motion of the convective system as a whole. The initial comparisons between the simulated DRVs and the BAMEX MCVs show that the simulated DRVs grew within background conditions of CAPE and shear similar to those observed for BAMEX MCVs and suggest that the same dynamical mechanisms are active. Because the BAMEX field campaign sampled MCVs in different backgrounds of CAPE and shear, the comparison also demonstrates the need to perform additional simulations to explore these different CAPE and shear regimes and to understand their impacts on the intensity and longevity of MCVs. Such a study has the additional benefit of placing MCV dynamics in an appropriate context for exploring their relevance to tropical cyclone formation.
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O’Gorman, Paul A. "The Effective Static Stability Experienced by Eddies in a Moist Atmosphere." Journal of the Atmospheric Sciences 68, no. 1 (January 1, 2011): 75–90. http://dx.doi.org/10.1175/2010jas3537.1.
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Abstract Water vapor directly affects the dynamics of atmospheric eddy circulations through the release of latent heat. But it is difficult to include latent heat release in dynamical theories because of the associated nonlinearity (precipitation generally occurs where there is upward motion). A new effective static stability is derived that fundamentally captures the effect of latent heat release on moist eddy circulations. It differs from the usual dry static stability by an additive term that depends on temperature and a parameter measuring the up–down asymmetry of vertical velocity statistics. Latent heat release reduces the effective static stability experienced by eddies but cannot reduce it to zero so long as there are nonprecipitating regions of the eddies. Evaluation based on reanalysis data indicates that the effective static stability in the lower troposphere ranges from ∼80% of the dry static stability at high latitudes to ∼25% in the tropics. The effective static stability provides a solution to the longstanding problem of how to adapt dry dynamical theories to the moist circulations in the atmosphere. Its utility for climate change problems is illustrated based on simulations with an idealized general circulation model. It is shown to help account for changes in the thermal stratification of the extratropical troposphere, the extent of the Hadley cells, the intensity of extratropical transient eddies, and the extratropical eddy length.
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Morrison, Hugh, and John M. Peters. "Theoretical Expressions for the Ascent Rate of Moist Deep Convective Thermals." Journal of the Atmospheric Sciences 75, no. 5 (May 2018): 1699–719. http://dx.doi.org/10.1175/jas-d-17-0295.1.
Повний текст джерелаАнотація:
An approximate analytic expression is derived for the ratio λ of the ascent rate of moist deep convective thermals and the maximum vertical velocity within them; λ is characterized as a function of two nondimensional buoyancy-dependent parameters y and h and is used to express the thermal ascent rate as a function of the buoyancy field. The parameter y characterizes the vertical distribution of buoyancy within the thermal, and h is the ratio of the vertically integrated buoyancy from the surface to the thermal top and the vertical integral of buoyancy within the thermal. Theoretical λ values are calculated using values of y and h obtained from idealized numerical simulations of ascending moist updrafts and compared to λ computed directly from the simulations. The theoretical values of [Formula: see text] 0.4–0.8 are in reasonable agreement with the simulated λ (correlation coefficient of 0.86). These values are notably larger than the [Formula: see text] from Hill’s (nonbuoyant) analytic spherical vortex, which has been used previously as a framework for understanding the dynamics of moist convective thermals. The relatively large values of λ are a result of net positive buoyancy within the upper part of thermals that opposes the downward-directed dynamic pressure gradient force below the thermal top. These results suggest that nonzero buoyancy within moist convective thermals, relative to their environment, fundamentally alters the relationship between the maximum vertical velocity and the thermal-top ascent rate compared to nonbuoyant vortices. Implications for convection parameterizations and interpretation of the forces contributing to thermal drag are discussed.
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Demoz, Belay B., Ruben Delgado, Brian Caroll, Kevin Vermeesch, David N. Whiteman, Ricardo Sakai, Sium Tesfay, and Lorenza Cooper. "Lidar Profiling In the lower Troposphere: experience from PECAN." EPJ Web of Conferences 176 (2018): 10004. http://dx.doi.org/10.1051/epjconf/201817610004.
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Results from the PECAN (Plains Elevated Convection at Night) campaign are discussed. In particular, the utility of simple backscatter lidars/ceilometers in quantifying atmospheric dynamics parameters and variables as well as evolution of the lower tropospheric dynamics are made. Cases of bore wave dynamics and the potential of these events in lofting of low level, moist, airmass and its consequence in thunderstorm initiation are made. A suite of thermodynamic profiling instruments are combined and compared to describe and visualize lower tropospheric dynamic evolution.
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Zhang, Fuqing, Naifang Bei, Richard Rotunno, Chris Snyder, and Craig C. Epifanio. "Mesoscale Predictability of Moist Baroclinic Waves: Convection-Permitting Experiments and Multistage Error Growth Dynamics." Journal of the Atmospheric Sciences 64, no. 10 (October 1, 2007): 3579–94. http://dx.doi.org/10.1175/jas4028.1.
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Abstract A recent study examined the predictability of an idealized baroclinic wave amplifying in a conditionally unstable atmosphere through numerical simulations with parameterized moist convection. It was demonstrated that with the effect of moisture included, the error starting from small random noise is characterized by upscale growth in the short-term (0–36 h) forecast of a growing synoptic-scale disturbance. The current study seeks to explore further the mesoscale error-growth dynamics in idealized moist baroclinic waves through convection-permitting experiments with model grid increments down to 3.3 km. These experiments suggest the following three-stage error-growth model: in the initial stage, the errors grow from small-scale convective instability and then quickly [O(1 h)] saturate at the convective scales. In the second stage, the character of the errors changes from that of convective-scale unbalanced motions to one more closely related to large-scale balanced motions. That is, some of the error from convective scales is retained in the balanced motions, while the rest is radiated away in the form of gravity waves. In the final stage, the large-scale (balanced) components of the errors grow with the background baroclinic instability. Through examination of the error-energy budget, it is found that buoyancy production due mostly to moist convection is comparable to shear production (nonlinear velocity advection). It is found that turning off latent heating not only dramatically decreases buoyancy production, but also reduces shear production to less than 20% of its original amplitude.
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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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Yamada, Ray, and Olivier Pauluis. "Momentum Balance and Eliassen–Palm Flux on Moist Isentropic Surfaces." Journal of the Atmospheric Sciences 73, no. 3 (February 15, 2016): 1293–314. http://dx.doi.org/10.1175/jas-d-15-0229.1.
Повний текст джерелаАнотація:
Abstract Previous formulations for the zonally averaged momentum budget and Eliassen–Palm (EP) flux diagnostics do not adequately account for moist dynamics, since air parcels are not differentiated by their moisture content when averages are taken. The difficulty in formulating the momentum budget in moist coordinates lies in the fact that they are generally not invertible with height. Here, a conditional-averaging approach is used to derive a weak formulation of the momentum budget and EP flux in terms of a general vertical coordinate that is not assumed to be invertible. The generalized equation reduces to the typical mass-weighted zonal-mean momentum equation for invertible vertical coordinates. The weak formulation is applied here to study the momentum budget on moist isentropes. Recent studies have shown that the meridional mass transport in the midlatitudes is twice as strong on moist isentropes as on dry isentropes. It is shown here that this implies a similar increase in the EP flux between the dry and moist frameworks. Physically, the increase in momentum exchange is tied to an enhancement of the form drag associated with the horizontal structure of midlatitude eddies, where the poleward flow of moist air is located in regions of strong eastward pressure gradient.
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Atamanyuk, Volodymyr, and Yaroslav Gumnytskyi. "Mass Exchange Dynamics During the Second Filtration Drying Period." Chemistry & Chemical Technology 3, no. 2 (June 15, 2009): 129–37. http://dx.doi.org/10.23939/chcht03.02.129.
Повний текст джерелаАнотація:
The work is dedicated to theoretical and experimental investigations of kinetics and dynamics of filtration drying of capillary and pore materials, and mineral granulated fertilizers, in particular. The proposed physical model of a moist particle and the differential system of equations which describes heat exchange in the second drying period enables to determine the transfer velocity of mass-exchange zone in a dispersion layer of the material during filtration drying.
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Talemos, Seta, Demissew Sebsebe, and Woldu Zerihun. "Litterfall dynamics in Boter-Becho Forest: Moist evergreen montane forest of Southwestern Ethiopia." Journal of Ecology and The Natural Environment 10, no. 1 (January 31, 2018): 13–21. http://dx.doi.org/10.5897/jene2017.0648.
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Gautam, Tilak Prasad, and Tej Narayan Mandal. "Effect of disturbance on litter dynamics in moist tropical forest of eastern Nepal." Our Nature 14, no. 1 (January 23, 2017): 1–12. http://dx.doi.org/10.3126/on.v14i1.16435.
Повний текст джерелаАнотація:
Litterfall is an important vector of nutrient and carbon recycling in forest ecosystems. Present study was conducted in moist tropical forest of eastern Nepal to understand the effect of disturbance on litter dynamics. Litterfall was estimated at monthly intervals from one litter trap (1 m × 1 m) at each of the 70 sampling plots while litter mass accumulated at each sampling plot was collected once every season from one 1 m × 1 m plot. The total annual litterfall in undisturbed forest (UF) was 11.8 Mg ha−1 yr−1 which decreased by 54.2% in disturbed forest (DF). Leaves accounted for 69% (UF) to 76% (DF) of total litterfall while non-leaf litter formed the rest. Seasonal pattern exhibited a concentrated litterfall in summer season during March to June when more than 70% litterfall occurred in both stands. Forest floor litter mass also decreased due to forest disturbance. The total input of nutrients to the soil through litterfall in UF was more than double as compared to DF. The nutrient stocks in litter mass were in the order: N > K > P in both stands. Key disturbance activities like lopping, litter removal, tree felling, grazing, fire etc. in the peripheral part of the forest should be strictly prohibited by imposing rules and regulations so that status of biodiversity would be restored. This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
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You, Bo. "Dynamics of the three dimensional viscous primitive equations of large-scale moist atmosphere." Communications in Mathematical Sciences 19, no. 6 (2021): 1673–701. http://dx.doi.org/10.4310/cms.2021.v19.n6.a10.
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Dalling, J. W., M. D. Swaine, and Nancy C. Garwood. "DISPERSAL PATTERNS AND SEED BANK DYNAMICS OF PIONEER TREES IN MOIST TROPICAL FOREST." Ecology 79, no. 2 (March 1998): 564–78. http://dx.doi.org/10.1890/0012-9658(1998)079[0564:dpasbd]2.0.co;2.
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Pillai, Prasanth A., and H. Annamalai. "Moist Dynamics of Severe Monsoons over South Asia: Role of the Tropical SST*." Journal of the Atmospheric Sciences 69, no. 1 (January 1, 2012): 97–115. http://dx.doi.org/10.1175/jas-d-11-056.1.
Повний текст джерелаАнотація:
Abstract Diagnostics from observations and multicentury integrations of a coupled model [Geophysical Fluid Dynamics Laboratory (GFDL) coupled model version 2.1 (CM2.1)] indicate that about 65% of the severe monsoons (rainfall > 1.5 standard deviations of its long-term mean) over South Asia are associated with sea surface temperature (SST) anomalies over the equatorial Pacific during the developing phase of ENSO, and another 30% are associated with SST variations over the tropical Indo-Pacific warm pool. The present research aims to identify the moist processes that initiate the dryness (wetness) and provide a precursor for rainfall anomalies over South Asia in spring during El Niño (La Niña). The hypothesis in this paper, based on CM2.1 composites, is that at low levels El Niño–forced equatorial easterly wind anomalies over the Indian Ocean, resulting from Ekman pumping, promote anticyclonic vorticity over the northern Indian Ocean, whose poleward flank advects dry air from northern latitudes to South Asia. This is tested by performing ensemble simulations with the atmospheric component of CM2.1 (AM2.1) and applying moisture and moist static energy budgets. During El Niño, AM2.1 solutions capture the anticyclonic vorticity formation over the northern Indian Ocean 20–25 days earlier than organized negative rainfall anomalies over South Asia, and the advection of climatological air of lower moisture content by these anomalous winds initiates the dryness over South Asia from April onward. This long lead time embodied in this precursor signal can be exploited for predicting severe monsoons. During ENSO neutral conditions, the amplitude of regional SST anomalies during spring is insufficient to produce such a precursor signal. The dominance of the term warrants monitoring the three-dimensional moisture distribution for better understanding, modeling, and predicting of severe monsoons.
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Lee, David W. "Canopy dynamics and light climates in a tropical moist deciduous forest in India." Journal of Tropical Ecology 5, no. 1 (February 1989): 65–79. http://dx.doi.org/10.1017/s0266467400003229.
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ABSTRACTThe canopy dynamics and light climates within a 20 by 60 m quadrat were studied in a disturbed moist deciduous forest near Bombay, India. A map was drawn of individual trees within the quadrat, the taxa were identified, and their phenology was followed from November 1984 to July 1985. The quadrat contained 14 species, the most common being Tectona grandis, Terminalia tomentosa, Butea monosperma, Mitragyne parviflora and Albizia procera. Some individuals were in leaf at all times, more so at the moister east end of the quadrat. In November at the end of the rainy season, light measurements documented percentages of total daily photosynthetic photon fluence (PPF) at 10.0% of full sunlight; 44% of this flux was due to sun-flecks whose duration was approximately 17% of the daytime hours. Values for six sites were similar to mid-day measurements along a 40 m transect, and consistent with the 94% canopy cover of the sites, photographed with a fish-eye lens. The March dry season measurements revealed a more intense radiation environment (54% of solar PPF), and 59% of the photosynthetic photon flux density at mid-day along the transect. Canopy openings were increased to a mean of 59.4%. Light in the understorey in November was spectrally altered, with typical R:FR ratios of 0.30, compared to March values identical to those of sunlight, at 1.10.
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Rostami, M., and V. Zeitlin. "Understanding dynamics of large-scale atmospheric vortices with moist-convective shallow water model." Journal of Physics: Conference Series 738 (August 2016): 012055. http://dx.doi.org/10.1088/1742-6596/738/1/012055.
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Wang, Bin. "Dynamics of Tropical Low-Frequency Waves: An Analysis of the Moist Kelvin Wave." Journal of the Atmospheric Sciences 45, no. 14 (July 1988): 2051–65. http://dx.doi.org/10.1175/1520-0469(1988)045<2051:dotlfw>2.0.co;2.
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Spyksma, K., and P. Bartello. "Predictability in Wet and Dry Convective Turbulence." Journal of the Atmospheric Sciences 65, no. 1 (January 1, 2008): 220–34. http://dx.doi.org/10.1175/2007jas2307.1.
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Abstract There is a growing interest in understanding the role that moisture plays in atmospheric dynamics, particularly in its effect on predictability. Current research indicates that when moisture effects are added to an atmospheric model, the error growth produced by the new moist dynamics reduces the predictability times, especially at the scales of moist convection. The issue of moist convection’s effect on predictability is addressed herein. By performing high-resolution large-ensemble runs, it is shown that although nonprecipitating moist convection is less predictable than dry convection resulting from the same forcing, this effect can be explained by the energy injected into the system through the latent heating and cooling arising from the convective motion. This extra energy is spread evenly over most scales of the convective dynamics. When the predictability times are scaled to account for the extra kinetic energy, and the resulting earlier growth of error energy, wet and dry convection have very similar error growth characteristics. Sensitivity tests are performed to ensure that the results from the large ensembles have converged and that they are consistent with either changing resolution, diffusion levels, initial error energy length scales, or forcing amplitude.
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Siegelman, Lia, Patrice Klein, Andrew P. Ingersoll, Shawn P. Ewald, William R. Young, Annalisa Bracco, Alessandro Mura, et al. "Moist convection drives an upscale energy transfer at Jovian high latitudes." Nature Physics 18, no. 3 (January 10, 2022): 357–61. http://dx.doi.org/10.1038/s41567-021-01458-y.
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AbstractJupiter’s atmosphere is one of the most turbulent places in the solar system. Whereas observations of lightning and thunderstorms point to moist convection as a small-scale energy source for Jupiter’s large-scale vortices and zonal jets, this has never been demonstrated due to the coarse resolution of pre-Juno measurements. The Juno spacecraft discovered that Jovian high latitudes host a cluster of large cyclones with diameter of around 5,000 km, each associated with intermediate- (roughly between 500 and 1,600 km) and smaller-scale vortices and filaments of around 100 km. Here, we analyse infrared images from Juno with a high resolution of 10 km. We unveil a dynamical regime associated with a significant energy source of convective origin that peaks at 100 km scales and in which energy gets subsequently transferred upscale to the large circumpolar and polar cyclones. Although this energy route has never been observed on another planet, it is surprisingly consistent with idealized studies of rapidly rotating Rayleigh–Bénard convection, lending theoretical support to our analyses. This energy route is expected to enhance the heat transfer from Jupiter’s hot interior to its troposphere and may also be relevant to the Earth’s atmosphere, helping us better understand the dynamics of our own planet.
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Yamada, Ray, and Olivier Pauluis. "Wave–Mean-Flow Interactions in Moist Baroclinic Life Cycles." Journal of the Atmospheric Sciences 74, no. 7 (June 19, 2017): 2143–62. http://dx.doi.org/10.1175/jas-d-16-0329.1.
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Abstract Previous studies show that the moist Eliassen–Palm (EP) flux captures a greater eddy momentum exchange through form drag than the dry EP flux in the midlatitude climate. This suggests that the eddy moisture flux acts to decrease the baroclinicity of the zonal jet. This study investigates such a mechanism in moist baroclinic life cycles, which are simulated in an idealized general circulation model with large-scale condensation as the only moist process. The runs are analyzed using a linear diagnostic based on the Kuo–Eliassen equation to decompose the jet change into parts driven by individual forcing terms. It is shown that the wave-induced latent heating drives an indirect Eulerian-mean cell on the equatorward flank of the jet, which acts to reduce the baroclinicity in that region. The eddy sensible heat fluxes act to reduce the baroclinicity near the center of the jet. The moist baroclinic forcing strengthens as the amount of initially available moisture increases. The effect of the eddy moisture flux on the transformed Eulerian-mean (TEM) and isentropic dynamics is also considered. It is shown that the circulation and EP flux on moist isentropes is around 4 times as strong and extends farther equatorward than on dry isentropes. The equatorward extension of the moist EP flux coincides with the region where the baroclinic forcing is driven by latent heating. The moist EP flux successfully captures the moisture-driven component of the baroclinic forcing that is not seen in the dry EP flux.
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Dias, Juliana, and Olivier Pauluis. "Impacts of Convective Lifetime on Moist Geostrophic Adjustment." Journal of the Atmospheric Sciences 67, no. 9 (September 1, 2010): 2960–71. http://dx.doi.org/10.1175/2010jas3405.1.
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Abstract This paper presents a theoretical study of the effects of moist convection on geostrophic adjustment in an infinite channel. The governing equations correspond to a linearized shallow water system of equations for the atmosphere first vertical baroclinic mode, which is coupled to a vertically averaged moisture equation. The coupling is through a parameterization that represents precipitation. The transient behavior and final state of the flow initially at rest with active precipitation limited to half of the channel is investigated, both numerically and analytically. It is shown that an initial imbalance resulting from precipitation induces a circulation that dries out the nonprecipitating region and further enhances precipitation. This interaction between precipitation and dynamics leads to a sharper temperature gradient and stronger jet in the final state, when compared to the dry adjustment. Unlike in the dry case, the moist geostrophic adjustment cannot be entirely determined from the initial unbalanced flow, since it depends on the time scale for convection. Analytic approximations are derived in limits of both fast and slow convective adjustment time.
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PÉLISSIER, RAPHAËL. "Tree spatial patterns in three contrasting plots of a southern Indian tropical moist evergreen forest." Journal of Tropical Ecology 14, no. 1 (January 1998): 1–16. http://dx.doi.org/10.1017/s0266467498000017.
Повний текст джерелаАнотація:
In a primary dense moist evergreen forest of southern India, spatial patterns of trees ≥30 cm gbh were investigated from three contrasting 0.4-ha plots that differed in topography and amount of disturbance due to treefall. Exploratory data analysis is based on second-order neighbourhood and pair-correlation statistics used to describe the degree of clustering/regularity in patterns of all trees, and the degree of attraction/repulsion between young trees and adults. Stochastic simulations from the Markov point process models are then used to fit spatial interaction models. The results show that spatial patterns can be related to particular dynamic processes which depend on both exogenous and endogenous factors: on steep slopes disturbed by many treefalls, spatial pattern displays large clusters which can be interpreted as within-gap regeneration stages of various ages, while in areas undisturbed over a long period, interactions between young trees and adults give rise to spatial patterns consistent with substitution dynamic processes implying standing mortality rather than treefalls. Characterizing forest dynamics through spatial patterns of trees opens up the possibility of mapping structural units that might be considered as elementary functional patches of the forest mosaic.
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Singh, H. P., and Samir Sarkar. "Vegetational dynamics of Tertiary Himalaya." Journal of Palaeosciences 38 (December 31, 1989): 333–44. http://dx.doi.org/10.54991/jop.1989.1668.
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Selected palaeobotanical and palynological records published from the Tertiary Period of Himalaya have been examined and a generalized vegetational frame work has been reconstructed. The diverse Palaeogene floras of Himalaya are marked by moist deciduous and wet semi-evergreen forest types growing mostly under tropical climate in varying type of environments. The tropical families register a decline in the Early Miocene time. The Middle Miocene Himalayan orogeny coincides with proliferation of Abietineae and by the appearance of several subtropical floral elements. Development and diversity of forest types are controlled by the altitudinal belts. The Pliocene floral diversification is related to climatic changes and increased continentality. The wet tropical forests disappeared from the low altitudes, whereas wet subtropical and temperate forests were transformed into dry or moist vegetational types. The appearance of semi-arid and cold conditions forced several moisture-loving plants, either to migrate or perish. The modern composition of the Himalayan flora reveals that it is a partial continuum of Neogene floras which have been progressively enriched by the appearance of several immigrant elements and also by the changes brought in due to evolutionary processes.