This study investigates the adjustment of large-scale localized buoyancy anomalies in mid-latitude regions and the nonlinear evolution of associated condensation patterns in both adiabatic and moist-convective environments. This... more
This study investigates the adjustment of large-scale localized buoyancy
anomalies in mid-latitude regions and the nonlinear evolution of associated
condensation patterns in both adiabatic and moist-convective environments.
This investigation is carried out utilizing the two-layer idealized moist-
convective thermal rotating shallow water (mcTRSW) model. Our investigation reveals that the presence of a circular positive potential temperature anomaly in the lower layer initiates an anticyclonic high-pressure rotation, accompanied by a negative buoyancy anomaly in the upper layer, resulting in an anisotropic northeast–southwest tilted circulation of heat flux. The evolution of eddy heat fluxes, such as poleward heat flux, energy, and meridional elongation of the buoyancy field, heavily depends on the perturbation's strength, size, and vertical structure. The heatwave initiates atmospheric instability, leading to precipitation systems such as rain bands and asymmetric latent heat release due to moist convection in a diabatic environment. This creates a comma cloud pattern in the upper troposphere and a comma-shaped buoyancy anomaly in the lower layer, accompanied by the emission of inertia gravity waves. The southern and eastern sectors of the buoyancy anomaly show an upward flux, generating a stronger cross-equatorial flow and inertia-gravity waves in a southward and eastward direction. Furthermore, the simulations reveal a similar asymmetric pattern of total condensed liquid water content distribution, accompanied by the intensification of moist convection as rain bands. This intensification is more pronounced in barotropic structures than in baroclinic configurations with stagnant upper layers. This study highlights the importance of considering moist convection and its effects on atmospheric and oceanic flows in mid-latitude regions, as well as the role of buoyancy anomalies in generating heatwaves and precipitation patterns.
anomalies in mid-latitude regions and the nonlinear evolution of associated
condensation patterns in both adiabatic and moist-convective environments.
This investigation is carried out utilizing the two-layer idealized moist-
convective thermal rotating shallow water (mcTRSW) model. Our investigation reveals that the presence of a circular positive potential temperature anomaly in the lower layer initiates an anticyclonic high-pressure rotation, accompanied by a negative buoyancy anomaly in the upper layer, resulting in an anisotropic northeast–southwest tilted circulation of heat flux. The evolution of eddy heat fluxes, such as poleward heat flux, energy, and meridional elongation of the buoyancy field, heavily depends on the perturbation's strength, size, and vertical structure. The heatwave initiates atmospheric instability, leading to precipitation systems such as rain bands and asymmetric latent heat release due to moist convection in a diabatic environment. This creates a comma cloud pattern in the upper troposphere and a comma-shaped buoyancy anomaly in the lower layer, accompanied by the emission of inertia gravity waves. The southern and eastern sectors of the buoyancy anomaly show an upward flux, generating a stronger cross-equatorial flow and inertia-gravity waves in a southward and eastward direction. Furthermore, the simulations reveal a similar asymmetric pattern of total condensed liquid water content distribution, accompanied by the intensification of moist convection as rain bands. This intensification is more pronounced in barotropic structures than in baroclinic configurations with stagnant upper layers. This study highlights the importance of considering moist convection and its effects on atmospheric and oceanic flows in mid-latitude regions, as well as the role of buoyancy anomalies in generating heatwaves and precipitation patterns.
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By means of a new multilayer pseudo-spectral moist-convective thermal rotating shallow-water (mcTRSW) model in a full sphere, we present a possible equatorial adjustment beyond Gill's mechanism for the genesis and dynamics of the... more
By means of a new multilayer pseudo-spectral moist-convective thermal rotating shallow-water (mcTRSW) model in a full sphere, we present a possible equatorial adjustment beyond Gill's mechanism for the genesis and dynamics of the Madden-Julian oscillation (MJO). According to this theory, an eastward-propagating MJO-like structure can be generated in a self-sustained and self-propelled manner due to nonlinear relaxation (adjustment) of a large-scale positive buoyancy anomaly, depressed anomaly, or a combination of these, as soon as this anomaly reaches a critical threshold in the presence of moist convection at the Equator. This MJO-like episode possesses a convectively coupled "hybrid structure" that consists of a "quasi-equatorial modon" with an enhanced vortex pair and a convectively coupled baroclinic Kelvin wave (BKW), with greater phase speed than that of dipolar structure on an intraseasonal timescale. Interaction of the BKW, after circumnavigating the entire Equator, with a new large-scale buoyancy anomaly may contribute to excitation of a recurrent generation of the next cycle of MJO-like structure. Overall, the generated "hybrid structure" captures a few of the crudest features of the MJO, including its quadrupolar structure, convective activity, condensation patterns, vorticity field, phase speed, and westerly and easterly inflows in the lower and upper troposphere. Although moisture-fed convection is a necessary condition for the "hybrid structure" to be excited and maintained in the proposed theory in this study, it is fundamentally different from moisture-mode theories, because the barotropic equatorial modon and BKW also exist in "dry" environments, while there are no similar "dry" dynamical basic structures in moisture-mode theories. The proposed theory can therefore be a possible mechanism to explain the genesis and backbone structure of the MJO and to converge some theories that previously seemed divergent. K E Y W O R D S equatorial modon, geostrophic adjustment, Madden-Julian oscillation, moist-convective thermal rotating shallow-water model This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
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An explanation of long-lived Saturn’s North Pole hexagonal circumpolar jet in terms of instability of the coupled system polar vortex - circumpolar jet is proposed in the framework of the rotating shallow water model, where scarcely known... more
An explanation of long-lived Saturn’s North Pole hexagonal circumpolar jet in terms of instability of the coupled system polar vortex - circumpolar jet is proposed in the framework of the rotating shallow water model, where scarcely known vertical structure of the Saturn’s atmosphere is averaged out. The absence of a hexagonal structure at the Saturn’s South Pole is explained along the same lines. By using the latest state-of-the-art observed winds in Saturn’s polar regions a detailed linear stability analysis of the circumpolar jet is performed (i) excluding (“jet-only" configuration), and (2) including (“jet+vortex" configuration) the north polar vortex in the system. A domain of parameters: latitude of the circumpolar jet and curvature of its azimuthal velocity profile, where the most unstable mode of the system has azimuthal wavenumber 6, is identified. Fully nonlinear simulations are then performed, initialized either with the most unstable mode of small amplitude, or...
Research Interests: Geochemistry, Geophysics, Computational Fluid Dynamics, Atmospheric Science, Fluid Dynamics, and 12 moreGFD (Fluid Dynamics), Planetary Atmospheres, Dynamic Stability Analysis, Tropical cyclones, Dynamic, Atmosphere, Icarus, Planetary wave dynamics, Dynamics of Droplets Films and Jets, Numerical and Experimental Methods in Fluid Dynamics, Shallow Water, and Tropical Cyclone
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Research Interests: Geochemistry, Geophysics, Computational Fluid Dynamics, Fluid Mechanics, Atmospheric Science, and 15 moreAtmospheric Physics, Atmospheric Modeling, Fluid Dynamics, Planetary Atmospheres, Environmental Fluid Mechanics, Atmospheric sciences, Atmosphere, Numerical Modeling of Atmosphere, Cyclone, Mecánica de fluidos, Icarus, Earth and Atmospheric Sciences, Numerical and Experimental Methods in Fluid Dynamics, Soil Plant Atmosphere, and Mars Polar Science
Research Interests: Geochemistry, Geophysics, Computational Fluid Dynamics, Atmospheric Science, Fluid Dynamics, and 12 moreGFD (Fluid Dynamics), Planetary Atmospheres, Dynamic Stability Analysis, Tropical cyclones, Dynamic, Atmosphere, Icarus, Planetary wave dynamics, Dynamics of Droplets Films and Jets, Numerical and Experimental Methods in Fluid Dynamics, Shallow Water, and Tropical Cyclone
Research Interests: Geophysics, Climate Change, Computational Fluid Dynamics, Fluid Mechanics, Atmospheric Science, and 15 moreClimatology, Computational Fluid Mechanics, Atmospheric Physics, Atmospheric Modeling, Atmospheric Dynamics, Fluid Dynamics, Flight Dynamics and Control, Geophysical Fluid Dynamics, Atmospheric sciences, Atmosphere, Mecanica de los Fluidos, Cyclone, GCMS and LCMS, Earth and Atmospheric Sciences, and Atmosphere and Ocean Dynamics
A simple two-layer model, the moist-convective rotating shallow water, which allows for low-cost high-resolution numerical simulations of the dynamics of the moist atmosphere in the presence of topography, is used to identify and... more
A simple two-layer model, the moist-convective rotating shallow water, which allows for low-cost high-resolution numerical simulations of the dynamics of the moist atmosphere in the presence of topography, is used to identify and understand dynamical processes governing the evolution of easterly waves propagating on the background of a low-latitude easterly jet crossing a land-sea boundary, a setup crudely representing the African Easterly Jet over the West-African plateau and the Atlantic ocean. We perform a thorough linear stability analysis and identify the unstable modes of the jet, which we use then for initialisation of fully nonlinear numerical simulations. In this way, we determine nonlinear evolution of unstable perturbations of the jet, both in the “dry” and moist-convective environments and highlight essential differences between the two cases. We identify a mechanism of formation of intense lower-layer cyclonic vortices at the northern flank of the jet and determine the influence of the land-sea contrast upon this process.
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Research Interests: Oceanography, Computational Fluid Dynamics, Fluid Mechanics, Atmospheric Science, Nonlinear Dynamics and Stochasticity, and 15 moreAtmospheric Physics, Atmospheric Modeling, Fluid Dynamics, Vortex dynamics, Tropical cyclones, Atmospheric sciences, Wake vortex modeling, Dynamic, Atmosphere, Mecanica de los Fluidos, Numerical Modeling of Atmosphere, Vortex, Dynamic Systems and Control, Numerical and Experimental Methods in Fluid Dynamics, and Shallow Water
The Aurignacian occurred in the middle of the Last Glacial Period, in which climate underwent major changes on millennial time scales, highlighted by the Greenland interstadial and stadial periods. Here we investigate how climate change... more
The Aurignacian occurred in the middle of the Last Glacial Period, in which climate underwent major changes on millennial time scales, highlighted by the Greenland interstadial and stadial periods. Here we investigate how climate change influenced the Aurignacian human dispersal in Europe and search for answers to several highly-debated questions in the Archaeology and Paleoanthropology. We use a global climate model to simulate the prototypical stadial and interstadial climate conditions and develop a human-existence potential (HEP) model to compute the probability of human existence by combining the climate data with archaeological site data. Using the HEP model, we reconstruct the patterns of human-existence probability and provide a pan-European overview of the Aurignacian human dispersal. The model results suggest that climate change significantly influences human dispersal, but there is evidence of human adaptation to climate. The Aurignacian dispersal is likely achieved in alternating modes of expansion and contraction. In comparison to interstadial times, human-existence probability in stadial times is largely reduced, but hot-spots exist in the climate shadows of large topographic features.
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Archaeological records indicate that many regions in Europe were unoccupied by hunter-gatherers during the Last Glacial Maximum (LGM), probably due to the harsh climatic conditions and glacial extent. In the populated regions of... more
Archaeological records indicate that many regions in Europe were unoccupied by hunter-gatherers during the Last Glacial Maximum (LGM), probably due to the harsh climatic conditions and glacial extent. In the populated regions of southwestern Europe, a new technocomplex, the Solutrean, is known to have emerged among hunter-gatherers but did not reach the regions east of 10°E. To better understand human occupation of Europe during the LGM, Human Existence Potential (HEP) is presented, which expresses the suitability for hunter-gatherers to inhabit a region under given environmental conditions. We estimate the HEP based on archaeological site locations and reconstructed climate/environment data. By geostatistic upscaling of archaeological site distributions into Core Areas, we distinguish areas that were likely to be continuously occupied by hunter-gatherers, from areas intermittently occupied. The use of Core Areas in the model is found to better describe regions of continuous human presence, removing some of the previously observed mismatches between reconstructions and archaeological records. Using HEP, important anthropological and archaeological questions can be studied. Environmental Human Catchment (EHC) and Best Potential Path (BPP) are applied to quantify an area of HEP attraction and the lowest-cost path between two areas, respectively. With these tools, we characterize the potential connections between the Core Areas, the environmental barriers and possible social and technological interactions. A clear difference in environmental adaptation is found between the populations in western and eastern Europe, and a significant climate barrier prevented the propagation of the Solutrean to eastern Europe.
Research Interests: Physics, Anthropology, Philosophical Anthropology, Climate Change, Paleoclimatology, and 12 moreClimatology, Modeling, Atmospheres (Architecture), Fluid Dynamics, Paleoclimate, Climate Change and coastal zones, Climate Change Impacts, LGM Palethnology, Atmosphere, Numerical Modeling of Atmosphere, Archelology, and Archeology
The so-called moist-convective shallow-water model, which incorporates moist convection in a simple albeit self-consistent way is used to analyse how intense localized vortices, with distributions of horizontal velocity and relative... more
The so-called moist-convective shallow-water model, which incorporates moist convection in a simple albeit self-consistent way is used to analyse how intense localized vortices, with distributions of horizontal velocity and relative vorticity close to those observed in tropical cyclones (TC), evolve and interact with topography on the β -plane at low latitudes. Instabilities of such TC-like vortices are studied first in the f -plane approximation, and their development, interplay with beta-gyres and the role they play in vorticity redistribution and intensification are then analysed along the vortex trajectories on the β -plane, both in dry and moist-convective environments. Interactions of the vortices with an idealized topography in the form of zonal and meridional ridges and islands of elliptic form and the role of moist convection in these processes are then investigated, revealing rich vortex-dynamics patterns. The results can be helpful in crude analyses and predictions of the evolution of the barotropic component of TC, of their trajectories over the ocean and during landfall and of related condensation/precipitation patterns.
Research Interests: Computational Fluid Dynamics, Fluid Mechanics, Fluid structure interaction, Numerical Analysis, Fluid Dynamics, and 14 moreGFD (Fluid Dynamics), Vortex dynamics, Tropical cyclones, Vortex Induced Vibrations, Environmental Fluid Mechanics, Computational Fluid Dynamics (CFD) modelling and simulation, Mecanica de los Fluidos, Cyclone, Vortex, Mecánica de fluidos, Fluidos, Numerical and Experimental Methods in Fluid Dynamics, Fluid Mechanics 7th Edition, and Tropical Cyclone
Atmospheric heavy metals have important environmental and health threats. To investigate atmospheric deposition and contamination of heavy metal elements in the glaciers of the eastern Tibetan Plateau (ETP), we collected the surface snow... more
Atmospheric heavy metals have important environmental and health threats. To investigate atmospheric deposition and contamination of heavy metal elements in the glaciers of the eastern Tibetan Plateau (ETP), we collected the surface snow (cryoconites) samples in the Lenglongling Glacier (LG), the Gannan Snowpack (GS), the Dagu Glacier (DG), the Hailuogou Glacier (HG) and Yulong Snow-mountain Glacier (YG) in summer 2017. Samples were analyzed for concentrations and enrichment factors (EFs) of Al and trace elements (Pb, Co, Cd, Ba, Mn, Ga, Sc, V, Zn, Cr, Ni, Cu, Rb, Sb, Cs, As, Mo, Li) using inductively coupled plasma-mass spectrometry (ICP-MS). Results showed that the concentrations and EFs of heavy metals (e.g. Sb, Cu, Cr, Ni, As, Mo) were generally high value in YG, GS and LG, while were relatively low value in DG and HG, implying that ETP glaciers may have been affected by atmospheric anthropogenic pollutants deposition to varying degrees. Comparing the heavy metal concentrations in the glaciers with those in the precipitation of middle/eastern China cities and also the South Asian cities, we find that the glacial heavy metal concentrations were generally low level, though the anthropogenic pollutants were still significantly enriched. Taking the spatial distribution of As and Ni concentration/EFs in the glaciers and surrounding urban precipitation as an example, we find that the heavy metal pollutants were probably transported to the glaciers through three routes from the surrounding densely populated area of Asia. The MODIS AOD and NCEP/NCAR wind vector also demonstrated that the atmospheric pollutants originated from anthropogenic emissions of urban areas of both South Asia, and northwest and east China, mainly caused by the large scale atmospheric circulation (e.g. the South Asian Monsoon, westerlies and Eastern Asian Summer Monsoon). Therefore, control of these potential pollution emission sources of the surrounding densely populated areas in Asia could be important to ETP glaciers in future perspectives.
Research Interests: Physics, Chemistry, Climate Change, Stable Isotope Analysis, Atmospheric Chemistry, and 15 moreAtmospheric Science, Tibetan Studies, Climatology, Atmospheric Physics, Atmospheres (Architecture), Tibet, MARINE POLLUTION, Air pollution, Environmental Chemistry, Environmental Sustainability, Climate Change Impacts, Ecosystem-Based Fisheries Management, Atmosphere, Atmosphere/ambiances, and Soil Plant Atmosphere
It is shown that steady large-scale slowly eastward-moving twin-cyclone coherent structures, the equatorial modons, exist in both one-and two layer versions of the rotating shallow water model on the equatorial beta plane. They arise via... more
It is shown that steady large-scale slowly eastward-moving twin-cyclone coherent structures, the equatorial modons, exist in both one-and two layer versions of the rotating shallow water model on the equatorial beta plane. They arise via the process of "ageostrophic adjustment" from the analytic asymptotic modon solutions of the vorticity equation obtained in the limit of small pressure perturbations. Evolution of these structures in adiabatic and moist-convective environments, and also in the presence of topography is analyzed, showing their robustness in the one-layer model. It is demonstrated that moist convection enhances and helps maintain the modons. In the two-layer model the barotropic and quasi-barotropic modons display similar to one-layer modon features, while increasing baroclinicity leads to eventual loss of coherence and arrest of the eastward propagation. Some features of equatorial modons resemble those observed in the Madden-Julian Oscillation events in tropical atmosphere, which hints at their possible relevance to the dynamics of this phenomenon.
Research Interests: Physics, Climate Change, Computational Fluid Dynamics, Fluid Mechanics, Atmospheric Science, and 15 moreAtmospheric Physics, Fluid structure interaction, Modeling and Simulation, Fluid Dynamics, GFD (Fluid Dynamics), Wave Structure Interaction, Equatorial Guinean literature, Atmospheric sciences, Atmosphere, Mecanica de los Fluidos, Wave Numerical Simulation, Mecánica de fluidos, Wave Hydrodynamics, Fluid Mechanics 7th Edition, and Shallow Water
Using the two-layer moist-convective rotating shallow water model, we study the process of relaxation (adjustment) of localized large-scale pressure anomalies in the lower equatorial troposphere, and show that it engenders coherent... more
Using the two-layer moist-convective rotating shallow water model, we study the process of relaxation (adjustment) of localized large-scale pressure anomalies in the lower equatorial troposphere, and show that it engenders coherent structures strongly resembling the Madden Julian Oscillation (MJO) events, as seen in vorticity, pressure, and moisture fields. We demonstrate that baroclinicity and moist convection substantially change the scenario of the quasi-barotropic “dry” adjustment, which was established in the framework of one-layer shallow water model and consists, in the long-wave sector, in the emission of equatorial Rossby waves, with dipolar meridional structure, to the West, and of equatorial Kelvin waves, to the East. If moist convection is strong enough, a dipolar cyclonic structure, which appears in the process of adjustment as a Rossby-wave response to the perturbation, transforms into a coherent modon-like structure in the lower layer, which couples with a baroclinic Kelvin wave through a zone of enhanced convection and produces, at initial stages of the process, a self-sustained slowly eastward-propagating zonally- dissymmetrical quadrupolar vorticity pattern. At the same time, a weaker quadrupolar structure of opposite sign arises in the upper layer, the whole picture similar to the active phase of the MJO events. The baroclinic Kelvin wave then detaches from the dipole, which keeps slow eastward motion, and circumnavigates the Equator, catching up and interacting with the dipole.
Research Interests: Physics, Theoretical Physics, Computational Fluid Dynamics, Fluid Mechanics, Atmospheric Science, and 14 moreNonlinear Dynamics and Stochasticity, Atmospheric Physics, Atmospheric Modeling, Fluid Dynamics, GFD (Fluid Dynamics), Equatorial Guinean literature, Simulation, Atmospheric sciences, Dynamic, Atmosphere, Numerical Modeling of Atmosphere, MJO, Earth and Atmospheric Sciences, and Shallow Water
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Atmospheric jets and vortices which, together with inertia-gravity waves, constitute the principal dynamical entities of large-scale atmospheric motions, are well described in the framework of one-or multi-layer rotating shallow water... more
Atmospheric jets and vortices which, together with inertia-gravity waves, constitute the principal dynamical entities of large-scale atmospheric motions, are well described in the framework of one-or multi-layer rotating shallow water models, which are obtained by vertically averaging of full "primitive" equations. There is a simple and physically consistent way to include moist convection in these models by adding a relaxational parameterization of precipitation and coupling precipitation with convective fluxes with the help of moist enthalpy conservation. We recall the construction of moist-convective rotating shallow water model (mcRSW) model and give an example of application to upper-layer atmospheric vortices.
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In this report, we present the contributions, outcomes, ideas, discussions and conclusions obtained at the PaleoMaps Workshop 2019, that took place at the Institute of Geography of the University of Cologne on 23 and 24 September 2019.... more
In this report, we present the contributions, outcomes, ideas, discussions and conclusions obtained at the PaleoMaps Workshop 2019, that took place at the Institute of Geography of the University of Cologne on 23 and 24 September 2019. The twofold aim of the workshop was: (1) to provide an overview of approaches and methods that are presently used to incorporate paleoenvironmental information in human–environment interaction modeling applications, and building thereon; (2) to devise new approaches and solutions that might be used to enhance the reconstruction of past human–environmental interconnections. This report first outlines the presented papers, and then provides a joint protocol of the often extensive discussions that came up following the presentations or else during the refreshment intervals. It concludes by adressing the open points to be resolved in future research avenues, e.g., implementation of open science practices, new procedures for reviewing of publications, and future concepts for quality assurance of the often complex paleoenvironmental data. This report may serve as an overview of the state of the art in paleoenvironment mapping and modeling. It includes an extensive compilation of the basic literature, as provided by the workshop attendants, which will itself facilitate the necessary future research.
Research Interests: Paleoanthropology, Paleontology, Physics, Anthropology, Atmospheric Chemistry, and 15 morePaleoclimatology, Atmospheric Science, Climatology, Atmospheric Physics, Atmospheric Modeling, Atmospheres (Architecture), Atmospheric Aerosols, History of Archeology, Atmospheric sciences, Atmosphere, Arqueología romana / Roman archeology, Paleoindian archaeology, Archeology, Earth and Atmospheric Sciences, and Paleotologia
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will... more
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Research Interests: Environmental Science, Geology, Physics, Stable Isotope Analysis, Atmospheric Chemistry, and 15 moreAtmospheric Science, Tibetan Studies, Environmental Geochemistry (Environmental Studies), Atmospheric Physics, MARINE POLLUTION, Isotope Geochemistry, Isotopic tracers, Isotopic Analysis, Ecosystem-Based Fisheries Management, Atmosphere, Elemental and Isotopic Analysis, Tibetan Plateau, Isotopic Geochemistry, Soilless, and Soil Plant Atmosphere
The process of geostrophic adjustment of localized large-scale pressure anomalies in the standard adiabatic shallow-water model on the equatorial beta-plane is revisited, and it is shown that the standard scenario of generation of... more
The process of geostrophic adjustment of localized large-scale pressure anomalies in the standard adiabatic shallow-water model on the equatorial beta-plane is revisited, and it is shown that the standard scenario of generation of westward-moving Rossby and eastward-moving Kelvin waves, which underlies the classical Gill theory of tropical circulation due to a localized heating, is not unique. Depending on the strength and aspect ratio of the initial perturbation, the response to the initial perturbation in the western sector can be dominated by inertia-gravity waves. The adjustment in the diabatic moist-convective shallow water model can be totally different and produces, depending on parameters, either Gill-like response or eastward-moving coherent dipolar structures of the type of equatorial modons, which do not appear in the “dry” adjustment, or vortices traveling, respectively, northwest in the Northern and southwest in the Southern hemispheres. (Physics of Fluids 31, 081702 (2019); https://doi.org/10.1063/1.5110441)
Research Interests: Physics, Computational Fluid Dynamics, Fluid Mechanics, Atmospheric Science, Nonlinear Dynamics and Stochasticity, and 14 moreAtmospheric Physics, Atmospheric Modeling, Modeling and Simulation, Fluid Dynamics, GFD (Fluid Dynamics), Physical Therapy, Equatorial Guinean literature, Simulation, Atmospheric sciences, Atmosphere, Mecanica de los Fluidos, Mecánica de fluidos, GCMS and LCMS, and Earth and Atmospheric Sciences
To investigate the large-scale trace element deposition and anthropogenic pollution in mountain glaciers of the northeastern Tibetan Plateau (TP) and its surrounding regions, we analyzed Al and 13 trace elements (As, Cd, Co, Cr, Cs, Cu,... more
To investigate the large-scale trace element deposition and anthropogenic pollution in mountain glaciers of the northeastern Tibetan Plateau (TP) and its surrounding regions, we analyzed Al and 13 trace elements (As, Cd, Co, Cr, Cs, Cu, Mn, Mo, Ni, Pb, Sb, V, and Zn) in glacier snowpacks collected at the Yuzhufeng, Laohugou No.12, and Qiyi glaciers (YG, LG12, and QG, respectively) in the northeastern TP as well as in the Miaoergou Glacier (MG) in the eastern Tianshan Mountains in June 2017. The concentrations and enrichment factors (EFs) of most trace elements (e.g., As, Cd, Co, Cr, Cu, Ni, and Sb) showed that the largest value appeared in the MG, followed by LG12, and the lowest value appeared in the QG, thereby implying a decreasing influence of anthropogenic emissions on these elements from the west (MG) to the east (QG). The YG inversely exhibited high concentrations but low EFs for As, Cd, Co, Cr, Cs, Cu, Pb, and Sb. Compared to the surrounding regions of the southern and western TP (e.g., Namsingle bondCo, Mt. Everest, and Pamirs), Japan, and Kathmandu, the trace element concentrations were relatively higher at the YG and MG but relatively lower at the LG12 and QG. The spatial distribution characteristics of trace elements (e.g., Pb and Sb) exhibited a gradually decreasing concentration from west to east in the Tianshan Mountains, and from south to north in the TP, implying two potential transport routes of atmospheric pollutants from Central and South Asia to the northeastern TP. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) backward trajectory model and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations/Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO/CALIOP) data reflected that these trace elements in the MG, LG12, and QG predominately originated from the western and surrounding areas, whereas in the YG they were mainly derived from a local source and South Asia through long-distance transport.
Research Interests: Atmospheric Chemistry, Atmospheric Science, Atmospheric Physics, Atmospheric Modeling, Atmospheric Aerosols, and 10 moreAtmospheric deposition, Atmospheric sciences, Atmosphere, Air Pollution, Climate Change, Atmospheric Studies, Atmosphere/ambiances, Soil-Water-Atmosphere-Plant Modeling - Farm Water management - Soil physics, Earth and Atmospheric Sciences, Modified Atmosphere Packing of Fruits, Soil Plant Atmosphere, and To Investigate the Atmospheric Condition Is Somali Country Recently
This study investigated the isotopic compositions of Hf, Nd, and Sr in aeolian dust deposited in several glacier basins of the northeast Tibetan Plateau in order to trace the source and provenance of long-range transported (LRT) dust in... more
This study investigated the isotopic compositions of Hf, Nd, and Sr in aeolian dust deposited in several glacier basins of the northeast Tibetan Plateau in order to trace the source and provenance of long-range transported (LRT) dust in the region. Transmission electron microscope (TEM) and energy dispersive X-ray spectrometer (EDX) measurements and dust size distributions both indicated that LRT dust was dominant in glacier cryoconite and snowpacks. Isotopes of Hf-Nd-Sr exhibited a generally heterogeneous geographic distribution that varied from north to south. The northern sites (e.g. Miaoergou Glacier) in the Tianshan Mountains showed much higher εNd and εHf values, whereas the southern sites (e.g. Yuzhufeng Glacier) in the Kunlun Mountains had lower εNd, with the Hf isotope exhibiting two parts: one positive εHf section and one negative εHf section. Lower 87Sr/86Sr ratios were apparent in the Miaoergou Glacier compared to other locations. In general, the Miaoergou Glacier had similar Hf-Nd-Sr isotopic compositions to those of southern Mongolian Gobi and Taklimakan Deserts. By contrast, Qilian Mountain locations exhibited similar Hf, Nd, and Sr isotopic compositions to those of the north Tibetan Plateau soil crust and Chinese Gobi Deserts. However, the Yuzhufeng Glacier, located in the hinterland of the Tibetan Plateau, had LRT dust that was derived predominantly from the north Tibetan Plateau desert and surface crust, but also partly from the Taklimakan desert. Compared with Ndsingle bondSr isotopes, Hfsingle bondNd isotopes provided new evidence for LRT dust transport. For example, the Yuzhufeng and Miaoergou Glaciers had similar Hfsingle bondNd isotopes to those of the Taklimakan Desert and Mongolian Gobi, respectively, implying the potential LRT dust source and atmospheric transport routes. The marked spatial differences in LRT dust source were mainly caused by large-scale atmospheric circulation interactions (e.g. the Mongolian High and Westerlies) during spring and summer. Wind stream analysis and MODIS AOD also demonstrated the potential differences in the sources of dust and the routes taken between northern and southern locations. This work provides new evidence and a more complete view of aeolian transport over the northeast Tibetan Plateau region under the current climate.
Research Interests: Soil Science, Stable Isotope Analysis, Atmospheric Chemistry, Atmospheric Science, Tibetan Studies, and 14 moreAtmospheric Physics, Atmospheric Modeling, Atmospheric Aerosols, Isotope Geochemistry, Amdo, Tibetan Plateau, Atmospheric sciences, Atmosphere, China, Tibetan Plateau, Qinghai, Tibetan Plateau, Soil Foundations, Earth and Atmospheric Sciences, Tibetan Plateau Grassland, Soil Plant Atmosphere, and Uplift of the Eastern Tibetan Plateau
We report a discovery of steady long-living slowly eastward moving large-scale coherent twin cyclones, the equatorial modons, in the shallow water model in the equatorial beta-plane, the archetype model of the ocean and atmosphere... more
We report a discovery of steady long-living slowly eastward moving large-scale coherent twin cyclones, the equatorial modons, in the shallow water model in the equatorial beta-plane, the archetype model of the ocean and atmosphere dynamics in tropics. We start by constructing analytical asymptotic modon solutions in the non-divergent velocity approximation and then show by simulations with a high-resolution numerical scheme that such configurations evolve into steady dipolar solutions of the full model. In the atmospheric context, the modons persist in the presence of moist convection, being accompanied and enhanced by specific patterns of water-vapour condensation. https://doi.org/10.1063/1.5080415
Research Interests: Physics, Computational Fluid Dynamics, Fluid Mechanics, Atmospheric Science, Atmospheric Physics, and 15 moreAtmospheric Modeling, Modeling and Simulation, Fluid Dynamics, GFD (Fluid Dynamics), Vortex dynamics, Tropical cyclones, Environmental Fluid Mechanics, Atmospheric sciences, Atmosphere, Cyclone Separators, Cyclone, Vortex, Equatorial waves, Earth and Atmospheric Sciences, and Shallow Water
We show how the two-layer moist-convective rotating shallow water model (mcRSW), which proved to be a simple and robust tool for studying effects of moist convection on large-scale atmospheric motions, can be improved by including, in... more
We show how the two-layer moist-convective rotating shallow water model (mcRSW), which proved to be a simple and robust tool for studying effects of moist convection on large-scale atmospheric motions, can be improved by including, in addition to the water vapour, precipitable water, and the effects of vaporisation, entrainment, and precipitation. Thus improved mcRSW becomes cloud-resolving. It is applied, as an illustration, to model the development of instabilities of tropical cyclone-like vortices.
Research Interests: Physics, Computational Fluid Dynamics, Fluid Mechanics, Atmospheric Science, Nonlinear Dynamics and Stochasticity, and 15 moreAtmospheric Physics, Atmospheric Modeling, Fluid Dynamics, GFD (Fluid Dynamics), Vortex dynamics, Tropical cyclones, Dynamic, Atmosphere, Mecanica de los Fluidos, Numerical Modeling of Atmosphere, Vortex, Dynamic Systems and Control, Numerical and Experimental Methods in Fluid Dynamics, Fluid Mechanics 7th Edition, and Shallow Water
The structure of Mars’ annular polar vortex is not similar to that of its counterpart on Earth and is characterised by a potential vorticity (PV) low in the vicinity of the winter pole, rather than PV monotonically increasing towards the... more
The structure of Mars’ annular polar vortex is not similar to that of its counterpart on Earth and is characterised by a potential vorticity (PV) low in the vicinity of the winter pole, rather than PV monotonically increasing towards the pole. A number of persistent asymmetric high-PV patches around the central low are also typical for the Martian polar vortex. The simplest vertically averaged model of the Mars atmosphere (a rotating shallow water model on the polar tangent plane) with inclusion of diabatic effects is used to get clues for understanding this surprising behaviour. The standard parameterisation of radiative relaxation is applied, together with a simple parameterisation of latent heat release due to spatially inhomogeneous CO2 deposition. The parametrisation of inhomogeneous deposition is new in this type of models, and includes dependence on the concentration of condensation nuclei, which are considered as a passive tracer. Linear stability analysis of the zonally and time averaged Mars’ winter polar vortex is performed, and thus identified unstable modes are used for initialisation of high-resolution numerical simulations of their nonlinear evolution in four different configurations (adiabatic, diabatic with only radiative relaxation, only deposition, and both radiative relaxation and deposition), in order to identify the role of each process. It is shown that the combined effect of radiative relaxation and inhomogeneous deposition can account for the observed, formally unstable structure of the polar vortex, including the patches of high potential vorticity. https://doi.org/10.1016/j.icarus.2018.05.026
Research Interests: Physics, Computational Fluid Dynamics, Fluid Mechanics, Atmospheric Science, Atmospheric Physics, and 15 moreAtmospheric Modeling, Fluid Dynamics, GFD (Fluid Dynamics), Planetary Atmospheres, Vortex dynamics, Environmental Fluid Mechanics, Atmospheric sciences, Atmosphere, Numerical Modeling of Atmosphere, Cyclone, Vortex, Mecánica de fluidos, Earth and Atmospheric Sciences, Numerical and Experimental Methods in Fluid Dynamics, and Mars Polar Science
An explanation of long-lived Saturn’s North Polar hexagonal circumpolar jet in terms of instability of the coupled system polar vortex - circumpolar jet is proposed in the framework of the rotating shallow water model, where scarcely... more
An explanation of long-lived Saturn’s North Polar hexagonal circumpolar jet in terms of instability of the coupled system polar vortex - circumpolar jet is proposed in the framework of the rotating shallow water model, where scarcely known vertical structure of the Saturn’s atmosphere is averaged out. The absence of a hexagonal structure at Saturn’s South Pole is explained similarly. By using the latest state-of-the-art observed winds in Saturn’s polar regions a detailed linear stability analysis of the circumpolar jet is performed (i) excluding (“jet-only” configuration), and (2) including (“jet + vortex” configuration) the north polar vortex in the system. A domain of parameters: latitude of the circumpolar jet and curvature of its azimuthal velocity profile, where the most unstable mode of the system has azimuthal wavenumber 6, is identified. Fully nonlinear simulations are then performed, initialized either with the most unstable mode of small amplitude, or with the random combination of unstable modes. It is shown that developing barotropic instability of the “jet+vortex” system produces a long-living structure akin to the observed hexagon, which is not the case of the “jet-only” system, which was studied in this context in a number of papers in literature. The north polar vortex, thus, plays a decisive dynamical role. The influence of moist convection, which was recently suggested to be at the origin of Saturn’s north polar vortex system in the literature, is investigated in the framework of the model and does not alter the conclusions. (https://doi.org/10.1016/j.icarus.2017.06.006)
Research Interests: Physics, Computational Fluid Dynamics, Atmospheric Science, Fluid Dynamics, GFD (Fluid Dynamics), and 11 morePlanetary Atmospheres, Dynamic Stability Analysis, Tropical cyclones, Computational Fluid Dynamics (CFD) modelling and simulation, Dynamic, Atmosphere, Planetary wave dynamics, Dynamics of Droplets Films and Jets, Numerical and Experimental Methods in Fluid Dynamics, Shallow Water, and Tropical Cyclone
Analysis of the influence of condensation and related latent heat release upon developing barotropic and baroclinic instabilities of large-scale low Rossby-number shielded vortices on the f-plane is performed within the moist-convective... more
Analysis of the influence of condensation and related latent heat release upon developing barotropic and baroclinic instabilities of large-scale low Rossby-number shielded vortices on the f-plane is performed within the moist-convective rotating shallow water model, in its barotropic (one-layer) and baroclinic (two-layer) versions. Numerical simulations with a high-resolution well-balanced finite-volume code, using a relaxation parameterisation for condensation, are made. Evolution of the instability in four different environments, with humidity (i) behaving as passive scalar, (ii) subject to condensation beyond a saturation threshold, (iii) subject to condensation and evaporation, with two different parameterisations of the latter, are inter-compared. The simulations are initialised with unstable modes determined from the detailed linear stability analysis in the "dry" version of the model. In a configuration corresponding to low-level mid-latitude atmospheric vortices, it is shown that the known scenario of evolution of barotropically unstable vortices, consisting in formation of a pair of dipoles ("dipolar breakdown") is substantially modified by condensation and related moist convection, especially in the presence of surface evaporation. No enhancement of the instability due to precipitation was detected in this case. Cyclone-anticyclone asymmetry with respect to sensitivity to the moist effects is evidenced. It is shown that inertia-gravity wave emission during the vortex evolution is enhanced by the moist effects. In the baroclinic configuration corresponding to idealised cutoff lows in the atmosphere, it is shown that the azimuthal structure of the leading unstable mode is sensitive to the details of stratification. Scenarios of evolution are completely different for different azimuthal structures, one leading to dipolar breaking, and another to tripole formation. The effects of moisture considerably enhance the perturbations in the lower layer, especially in the tripole formation scenario.