Literatura académica sobre el tema "Interactions surface troposphère"
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Artículos de revistas sobre el tema "Interactions surface troposphère"
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Perevedentsev, Y. P., N. V. Ismagilov, N. A. Mirsaeva, V. V. Guryanov, A. A. Nikolaev y K. M. Shantalinsky. "Seasonal Variations in Stratospheric Circulation and Interactions between the Troposphere and the Stratosphere". Известия Российской академии наук. Физика атмосферы и океана 59, n.º 6 (1 de noviembre de 2023): 720–30. http://dx.doi.org/10.31857/s000235152306007x.
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Based on the data of the ERA5 reanalysis, the dates of spring and autumn rearrangements of the stratospheric circulation on isobaric surfaces of 30, 20 and 10 gPa in the latitude zone of 30–90° C. in the period 1979–2020 were obtained. Of the 42 cases of spring restructuring, 10 belong to the early, 15 to the middle and 17 to the late. The spread in the dates of spring rearrangements on the surface of 10 hPa is 69 days. Most often, the spring restructuring of the circulation occurs from top to bottom, in some years, the delay of spring restructuring on the surface of 30 gPa relative to the surface of 10 gPa reaches 22–25 days. Autumn perestroika takes place from the bottom up and their terms at the 3 levels under consideration are close to each other. The relationship between the timing of the spring restructuring of the stratospheric circulation with solar activity and large sudden winter stratospheric warming is shown. Analysis of the fields of anomalies of daily temperature values and zonal wind velocity in the 1000-1 hPa layer in the period January-May showed their significant spatio-temporal difference in the case of early and late spring perestroika. Thus, foci of positive anomalies of temperature and wind speed are formed initially in the upper stratosphere, and then shifted from top to bottom. The interrelations between the layers of the atmosphere in different seasons are considered.
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Cohen, Judah, Mathew Barlow, Paul J. Kushner y Kazuyuki Saito. "Stratosphere–Troposphere Coupling and Links with Eurasian Land Surface Variability". Journal of Climate 20, n.º 21 (1 de noviembre de 2007): 5335–43. http://dx.doi.org/10.1175/2007jcli1725.1.
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Abstract A diagnostic of Northern Hemisphere winter extratropical stratosphere–troposphere interactions is presented to facilitate the study of stratosphere–troposphere coupling and to examine what might influence these interactions. The diagnostic is a multivariate EOF combining lower-stratospheric planetary wave activity flux in December with sea level pressure in January. This EOF analysis captures a strong linkage between the vertical component of lower-stratospheric wave activity over Eurasia and the subsequent development of hemisphere-wide surface circulation anomalies, which are strongly related to the Arctic Oscillation. Wintertime stratosphere–troposphere events picked out by this diagnostic often have a precursor in autumn: years with large October snow extent over Eurasia feature strong wintertime upward-propagating planetary wave pulses, a weaker wintertime polar vortex, and high geopotential heights in the wintertime polar troposphere. This provides further evidence for predictability of wintertime circulation based on autumnal snow extent over Eurasia. These results also raise the question of how the atmosphere will respond to a modified snow cover in a changing climate.
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Marcheggiani, Andrea y Thomas Spengler. "Diabatic effects on the evolution of storm tracks". Weather and Climate Dynamics 4, n.º 4 (3 de noviembre de 2023): 927–42. http://dx.doi.org/10.5194/wcd-4-927-2023.
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Abstract. Despite the crucial role of moist diabatic processes in mid-latitude storm tracks and related model biases, we still lack a more complete theoretical understanding of how diabatic processes affect the evolution of storm tracks. To alleviate this shortcoming, we investigate the role of diabatic processes in the evolution of the northern hemispheric storm tracks using a framework based on the tendency of the slope of isentropic surfaces as a measure of baroclinic development. We identify opposing behaviours in the near-surface and free troposphere for the relationship between the flattening of the slope of isentropic surfaces and its restoration by diabatic processes. Near the surface (900–825 hPa), cold air advection associated with cold air outbreaks initially acts to flatten isentropic surfaces, with air–sea interactions ensuing to restore surface baroclinicity. In the free troposphere (750–350 hPa), on the other hand, the diabatic generation of the slope of isentropic surfaces precedes its depletion due to tilting by eddies, suggesting the primary importance of moist diabatic processes in triggering subsequent baroclinic development. The same phasing between diabatic and tilting tendencies of the slope is observed both in upstream and downstream sectors of the North Atlantic and North Pacific storm tracks. This suggests that the reversed behaviour between near-surface and free troposphere is a general feature of mid-latitude storm tracks. In addition, we find a correspondence between the diabatic generation of the slope of isentropic surfaces and enhanced precipitation as well as moisture availability, further underlining the crucial role of moisture and moist processes in the self-maintenance of storm tracks.
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Daibova, Elena B., Tamara S. Minakova, Valeriy S. Zakharenko, Natalia I. Kosova, Irina A. Kurzina y Alla B. Zotova. "Acid-Base and Photoinduced Processes on Magnesium-Containing Minerals and their Influence on the Troposphere Cleaning". Advanced Materials Research 1085 (febrero de 2015): 119–23. http://dx.doi.org/10.4028/www.scientific.net/amr.1085.119.
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Acid-base, adsorption and photosorption properties of microparticles surface of magnesium-containing compounds produced by dispersion of natural minerals after exposure to the air were studied. It was revealed that the reduction in predominant basicity of minerals surface in a range of periclase (MgO), brucite (Mg (OH)2) and magnesite (MgCO3) can be considered as a result of the presence of iron, silicon and magnesium oxide compounds. Quantum-chemical calculations made during the investigation, the decrease of pressure in the process of long-term contact of Freon 22 with the surface of MgO, irreversible character of adsorption and the absence of fluorine and chlorine-containing products in a gaseous phase give evidence of CFC destructive adsorption on the surface of magnesium oxide. The interaction of chlorine and fluorine derivatives of methane with the surface of aerosol particles from minerals in the darkness and under the influence of sunlight tropospheric radiation was studied. The evaluation of such interactions influence on the process of the Earth troposphere purification from carbon dioxide and dichlorofluoromethane during their adsorption and photosorption on the surface of precipitated aerosol was made.
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Ait-Chaalal, Farid y Tapio Schneider. "Why Eddy Momentum Fluxes are Concentrated in the Upper Troposphere". Journal of the Atmospheric Sciences 72, n.º 4 (31 de marzo de 2015): 1585–604. http://dx.doi.org/10.1175/jas-d-14-0243.1.
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Abstract The extratropical eddy momentum flux (EMF) is controlled by generation, propagation, and dissipation of large-scale eddies and is concentrated in Earth’s upper troposphere. An idealized GCM is used to investigate how this EMF structure arises. In simulations in which the poles are heated more strongly than the equator, EMF is concentrated near the surface, demonstrating that surface drag generally is not responsible for the upper-tropospheric EMF concentration. Although Earth’s upper troposphere favors linear wave propagation, quasi-linear simulations in which nonlinear eddy–eddy interactions are suppressed demonstrate that this is likewise not primarily responsible for the upper-tropospheric EMF concentration. The quasi-linear simulations reveal the essential role of nonlinear eddy–eddy interactions in the surf zone in the upper troposphere, where wave activity absorption away from the baroclinic generation regions occurs through the nonlinear generation of small scales. In Earth-like atmospheres, wave activity that is generated in the lower troposphere propagates upward and then turns meridionally, eventually being absorbed nonlinearly in the upper troposphere. The level at which the wave activity begins to propagate meridionally appears to be set by the typical height reached by baroclinic eddies. This can coincide with the tropopause height but also can lie below it if convection controls the tropopause height. In the latter case, EMF is maximal well below the tropopause. The simulations suggest that EMF is concentrated in Earth’s upper troposphere because typical baroclinic eddies reach the tropopause.
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Kim, So-Young, Song-You Hong, Young Cheol Kwon, Yong Hee Lee y Da-Eun Kim. "Effects of Modified Surface Roughness Length over Shallow Waters in a Regional Model Simulation". Atmosphere 10, n.º 12 (16 de diciembre de 2019): 818. http://dx.doi.org/10.3390/atmos10120818.
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The effects of modified sea-surface roughness length over shallow waters are examined in a regional climate simulation over East Asia centered on the Korean Peninsula, using the Advanced Research Weather Research and Forecasting model (WRF-ARW). The control experiment calculates the sea-surface roughness length as a function of friction velocity based on the Charnock relationship. The experiment considering water depth in the sea-surface roughness length over shallow waters is compared with the control experiment. In the experiment considering water depth, the excessive near-surface wind speed over shallow waters is reduced compared to that of the control experiment. Wind speed is reduced also in the lower troposphere. The effects of modified surface roughness over shallow waters are not localized to the lower troposphere but extended into the upper troposphere. Through the vertical interaction between the lower and upper levels, upper tropospheric wind—which is underestimated in the control experiment—is enhanced in the experiment with modified sea-surface roughness length, not only over the shallow waters, but also over the entire domain. As a result, the vertical shear of zonal wind increases, leading to the enhancement of the negative meridional temperature gradient in the mid troposphere.
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Haase, Sabine y Katja Matthes. "The importance of interactive chemistry for stratosphere–troposphere coupling". Atmospheric Chemistry and Physics 19, n.º 5 (18 de marzo de 2019): 3417–32. http://dx.doi.org/10.5194/acp-19-3417-2019.
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Abstract. Recent observational and modeling studies suggest that stratospheric ozone depletion not only influences the surface climate in the Southern Hemisphere (SH), but also impacts Northern Hemisphere (NH) spring, which implies a strong interaction between dynamics and chemistry. Here, we systematically analyze the importance of interactive chemistry with respect to the representation of stratosphere–troposphere coupling and in particular the effects on NH surface climate during the recent past. We use the interactive and specified chemistry version of NCAR's Whole Atmosphere Community Climate Model coupled to an ocean model to investigate differences in the mean state of the NH stratosphere as well as in stratospheric extreme events, namely sudden stratospheric warmings (SSWs), and their surface impacts. To be able to focus on differences that arise from two-way interactions between chemistry and dynamics in the model, the specified chemistry model version uses a time-evolving, model-consistent ozone field generated by the interactive chemistry model version. We also test the effects of zonally symmetric versus asymmetric prescribed ozone, evaluating the importance of ozone waves in the representation of stratospheric mean state and variability. The interactive chemistry simulation is characterized by a significantly stronger and colder polar night jet (PNJ) during spring when ozone depletion becomes important. We identify a negative feedback between lower stratospheric ozone and atmospheric dynamics during the breakdown of the stratospheric polar vortex in the NH, which contributes to the different characteristics of the PNJ between the simulations. Not only the mean state, but also stratospheric variability is better represented in the interactive chemistry simulation, which shows a more realistic distribution of SSWs as well as a more persistent surface impact afterwards compared with the simulation where the feedback between chemistry and dynamics is switched off. We hypothesize that this is also related to the feedback between ozone and dynamics via the intrusion of ozone-rich air into polar latitudes during SSWs. The results from the zonally asymmetric ozone simulation are closer to the interactive chemistry simulations, implying that under a model-consistent ozone forcing, a three-dimensional (3-D) representation of the prescribed ozone field is desirable. This suggests that a 3-D ozone forcing, as recommended for the upcoming CMIP6 simulations, has the potential to improve the representation of stratospheric dynamics and chemistry. Our findings underline the importance of the representation of interactive chemistry and its feedback on the stratospheric mean state and variability not only in the SH but also in the NH during the recent past.
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Abbatt, Jonathan P. D. "Interaction of HNO3with water-ice surfaces at temperatures of the free troposphere". Geophysical Research Letters 24, n.º 12 (15 de junio de 1997): 1479–82. http://dx.doi.org/10.1029/97gl01403.
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Daibova, Elena B., Tamara S. Minakova, Valeriy S. Zakharenko, Natalia I. Kosova, Irina A. Kurzina, Магina E. Kirillova y Ludmila Yu Minakova. "Physicochemical and Photosorption Properties of Oxygen-Containing Calcium Compounds – Components of Troposferic Aerosol". Advanced Materials Research 1085 (febrero de 2015): 124–29. http://dx.doi.org/10.4028/www.scientific.net/amr.1085.124.
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The Importance of this Paper is Determined by the Research of Conditions of Photosorption Processes Occurance on the Surface of Aerosol Particles Resulting in the Removal of Toxic Substances from the Atmosphere. Acid-Base Properties of Oxygen-Containing Calcium Compounds being Components of Troposphere Aerosol Particles were Studied by Methods of Ph-Metry and Hammet’s Indicators. the Basic Properties of the Investigated Compounds Surfaces are Predominant Ones: рНiis of Calcium Oxide and Hydroxide has a Value of 9.3 – 9.5, and that for Carbonate and Calcite Equals to 12.3-12.4. Indicator Method Distinguishes Three Areas of Spectrum Corresponding to Lewis Base, and Brensted Neutral and Basic Centers. the Intencity of Peaks is much Higher for Ca(OH)2 and CaO. the Interaction Process of Halogen-Containing Organic Compounds (Freons: 134a, 22 and 12) with Calcium Carbonate Surface under Illumination in Conditions close to Tropospheric Conditions was Studied. it is Shown that the Interaction is the Destructive Photosorption of Freons (134a or 22). the Spectral Dependence of Effective Quantum Yield of Destructive Photosorption is Determined. as a Result of the Interaction Calcium Fluoride and Calcium Chloride are Formed at the Surface.
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Qin, Huiling y Hiroshi Kawamura. "Air-sea interaction throughout the troposphere over a very high sea surface temperature phenomenon". Geophysical Research Letters 37, n.º 1 (enero de 2010): n/a. http://dx.doi.org/10.1029/2009gl041685.
Texto completoTesis sobre el tema "Interactions surface troposphère"
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Guion, Antoine. "Droughts and heatwaves in the Western Mediterranean, impact on ozone pollution". Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS056.
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Sécheresses et vagues de chaleur sont des événements extrêmes capables d’impacter à la fois la végétation et la chimie de l’atmosphère, notamment par l’intermédiaire d’interactions entre la surface et la troposphère. L’objectif de cette thèse est d’évaluer leurs effets sur la biomasse, l’activité des incendies et la pollution à l’ozone dans l’Ouest Méditerranéen. Cette étude se base principalement sur des modèles numériques régionaux de la surface terrestre (hydrologie et végétation) et de l'atmosphère (météorologie et chimie atmosphérique). En complément, plusieurs jeux de données d’observations in situ et satellitaires sont utilisés.Identifiant sécheresses et vagues de chaleur sur la période 1979-2016 (WRF-ORCHIDEE), j’ai mis en avant leur distribution spatiale et temporelle. Sur base d’observations (MODIS), j’ai démontré que le déclin de l’activité végétale (diminution de la biomasse) est principalement attribuable aux sécheresses alors que l’augmentation en intensité des incendies résulte d’une synergie entre sécheresses et canicules. Finalement, ces événements mènent tous deux à une augmentation de la concentration de surface en ozone incluant des pics de pollution simulés (CHIMERE) et observés (AQ e-Reporting). Ceci s’explique par une augmentation des émissions de précurseurs, une diminution du dépôt sec dans la canopée et des conditions météorologiques favorablesDroughts and heatwaves are extreme events able to affect both vegetation and atmospheric chemistry, notably through surface-troposphere interactions. The objective of this thesis is to assess their effects on biomass, fire activity and ozone pollution in the western Mediterranean. This study is mainly based on regional numerical models of the land surface (hydrology and vegetation) and the atmosphere (meteorology and atmospheric chemistry). In addition, several datasets of in situ and satellite observations are used.Identifying droughts and heatwaves over the period 1979-2016 (WRF-ORCHIDEE), I highlighted their spatial and temporal distribution. Based on observations (MODIS), I demonstrated that the decline in vegetation activity (decrease in biomass) is mainly attributable to droughts, while the increase in fire intensity results from a synergy between droughts and heatwaves. Finally, these events both lead to an increase in surface ozone concentration including simulated (CHIMERE) and observed (AQ e-Reporting) pollution peaks. This is explained by an increase in precursor emissions, a decrease in dry deposition in the canopy and favourable meteorological conditions for photochemistry
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Fernandez, M. A. "The heterogeneous interaction of trace gases with ice surfaces at temperatures of the upper troposphere". Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598992.
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The uptake of HNO3 and HCI on water-ice films has been investigated using a coated wall flow reactor at temperatures typical of the upper troposphere. The uptake was followed by sensitive detection of gaseous species using a quadruple mass spectrometer. The uptake coefficients and surface coverage have been measured as a function of temperature (205 – 250) and reactant partial pressure (~10-7 Torr). Using a Langmuir absorption isotherm and the surface coverage data, the enthalpy and entropy of absorption have been evaluated. The uptake coefficients showed a negative temperature dependence in both cases. It was concluded that HNO3 has a higher propensity for absorption to ice than HC1 under these conditions. Competitive absorption experiments confirmed this conclusion. HNO3 was found to promote HC1 desorption when both gases were exposed to an ice surface simultaneously. The surface coverage of HC1 on HNO3-doped ice was found to be an order of magnitude lower and completely reversible compared to the uptake on bare ice. It was concluded that in the presence of HNO3, reactions which require absorbed HC1 may be slower than anticipated on the basis of experiments which do not account for competitive absorption. One such reaction is C1ONO2 + HC1 → C12 + HNO3. The reactive uptake of C1ONO2 has been studied at 218 and 228 K and at partial pressures ~ 10-7 Torr. On bare ice, HOC1 was observed in the gas phase immediately upon exposure of C1ONO2. The uptake coefficient of C1ONO2 was found to have a weak negative partial pressure dependence. On HC1-doped ice, C12 was observed immediately upon C1ONO2 exposure. In a final set of experiments, HC1 was taken up onto HNO3-doped ice. The surface coverage of HC1 was an order of magnitude lower than on bare ice.
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Petitjean, Mélanie. "Interactions des composés organiques volatils avec des surfaces de glace pure ou dopée représentatives des conditions atmosphériques rencontrées dans la moyenne et la haute troposphére : application à la chimie des nuages mixtes et des cirrus". Strasbourg, 2010. https://publication-theses.unistra.fr/public/theses_doctorat/2010/PETITJEAN_Melanie_2010.pdf.
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La Haute Troposphère (HT) est caractérisée par ses basses températures, allant d'environ 188 à 233 K et par la présence de cirrus, des nuages constitués uniquement de glace et pouvant recouvrir jusqu'à 25% de la surface de la Terre. Les nuages mixtes et les cirrus peuvent constituer des puits potentiels pour un certain nombre d'espèces gazeuses et éventuellement promouvoir des réactions hétérogènes ou photochimiques Dans ce travail, nous nous proposons, en déterminant les isothermes d’adsorption sur des glaces pure et dopée entre 253 et 203K, de fournir des informations quantitatives sur la distribution des espèces organiques entre les phases gazeuse et condensée, à des températures rencontrées à des altitudes moyennes et dans la HT. La présence de Composés Organiques Volatils Oxygénés (COVO) tels que les alcools, aldéhydes, cétones et les acides carboxyliques, dans la HT est bien établie. En raison du rôle prépondérant des composés carbonylés dans la formation de photooxydants tels que l’ozone, ce travail de thèse s’est focalisé en particulier sur l’étude de ces composés afin d'évaluer si le piégeage sur des cristaux de glace et/ou des gouttelettes surfondues pouvait constituer un puits significatif dans les conditions atmosphériques. Par ailleurs, d’autres molécules (hydrocarbures aromatiques) ont été étudiées afin de mieux comprendre les relations entre la structure de la molécule et sa capacité à s’adsorber. En outre, des simulations numériques ont permis d’apporter des détails au niveau moléculaire sur la structure tridimensionnelle de la couche d’adsorption. Les pressions de vapeur saturante de l’hydroxyacétaldéhyde et de l'hydroxyacétone ont été déterminées pour la première fois en fonction de la température, apportant des valeurs de référence pour de futures études de laboratoire et permettant d'estimer leurs distributions dans l’atmosphère entre les phases gazeuse et particulaireThe upper troposphere (UT) is characterized by its low temperatures, from 188 to 233 K and the presence of cirrus clouds. These clouds, composed of ice crystals, can cover up to 25% of the Earth's surface. Mixed and cirrus clouds may be a potential sink for many gaseous species and can promote heterogeneous or photochemical reactions. In this work, the establishment of the adsorption isotherms on pure or doped ice surfaces between 253 and 203 K, provides quantitative information on the partitioning of organic species between the gas and condensed phases at temperatures encountered at medium altitudes and in the UT. The presence of Oxygenated Volatile Organic Compounds (OVOC) such as alcohols, aldehydes, ketones and carboxylic acids, in the UT is well established. As carbonyl compounds are involved in the formation of photooxidants such as ozone, this work has been focused on the study of these compounds. In addition, other molecules (aromatic hydrocarbons) have been studied to better understand the relationships between the structure of the molecule and its ability to be adsorbed on ice surfaces. Besides, computer simulations have led to some details at the molecular level on the three dimensional structure of the adsorption layer. This work has also allowed the determination of the vapor pressure of both hydroxyacetaldehyde and hydroxyacetone ,providing reference values for future laboratory studies and permitting estimation of their partitioning between the gas and particle atmospheric phases
Libros sobre el tema "Interactions surface troposphère"
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Xue, Yongkang, Yaoming Ma y Qian Li. Land–Climate Interaction Over the Tibetan Plateau. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.592.
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The Tibetan Plateau (TP) is the largest and highest plateau on Earth. Due to its elevation, it receives much more downward shortwave radiation than other areas, which results in very strong diurnal and seasonal changes of the surface energy components and other meteorological variables, such as surface temperature and the convective atmospheric boundary layer. With such unique land process conditions on a distinct geomorphic unit, the TP has been identified as having the strongest land/atmosphere interactions in the mid-latitudes.Three major TP land/atmosphere interaction issues are presented in this article: (1) Scientists have long been aware of the role of the TP in atmospheric circulation. The view that the TP’s thermal and dynamic forcing drives the Asian monsoon has been prevalent in the literature for decades. In addition to the TP’s topographic effect, diagnostic and modeling studies have shown that the TP provides a huge, elevated heat source to the middle troposphere, and that the sensible heat pump plays a major role in the regional climate and in the formation of the Asian monsoon. Recent modeling studies, however, suggest that the south and west slopes of the Himalayas produce a strong monsoon by insulating warm and moist tropical air from the cold and dry extratropics, so the TP heat source cannot be considered as a factor for driving the Indian monsoon. The climate models’ shortcomings have been speculated to cause the discrepancies/controversies in the modeling results in this aspect. (2) The TP snow cover and Asian monsoon relationship is considered as another hot topic in TP land/atmosphere interaction studies and was proposed as early as 1884. Using ground measurements and remote sensing data available since the 1970s, a number of studies have confirmed the empirical relationship between TP snow cover and the Asian monsoon, albeit sometimes with different signs. Sensitivity studies using numerical modeling have also demonstrated the effects of snow on the monsoon but were normally tested with specified extreme snow cover conditions. There are also controversies regarding the possible mechanisms through which snow affects the monsoon. Currently, snow is no longer a factor in the statistic prediction model for the Indian monsoon prediction in the Indian Meteorological Department. These controversial issues indicate the necessity of having measurements that are more comprehensive over the TP to better understand the nature of the TP land/atmosphere interactions and evaluate the model-produced results. (3) The TP is one of the major areas in China greatly affected by land degradation due to both natural processes and anthropogenic activities. Preliminary modeling studies have been conducted to assess its possible impact on climate and regional hydrology. Assessments using global and regional models with more realistic TP land degradation data are imperative.Due to high elevation and harsh climate conditions, measurements over the TP used to be sparse. Fortunately, since the 1990s, state-of-the-art observational long-term station networks in the TP and neighboring regions have been established. Four large field experiments since 1996, among many observational activities, are presented in this article. These experiments should greatly help further research on TP land/atmosphere interactions.
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Yang, Kun. Observed Regional Climate Change in Tibet over the Last Decades. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.587.
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The Tibetan Plateau (TP) is subjected to strong interactions among the atmosphere, hydrosphere, cryosphere, and biosphere. The Plateau exerts huge thermal forcing on the mid-troposphere over the mid-latitude of the Northern Hemisphere during spring and summer. This region also contains the headwaters of major rivers in Asia and provides a large portion of the water resources used for economic activities in adjacent regions. Since the beginning of the 1980s, the TP has undergone evident climate changes, with overall surface air warming and moistening, solar dimming, and decrease in wind speed. Surface warming, which depends on elevation and its horizontal pattern (warming in most of the TP but cooling in the westernmost TP), was consistent with glacial changes. Accompanying the warming was air moistening, with a sudden increase in precipitable water in 1998. Both triggered more deep clouds, which resulted in solar dimming. Surface wind speed declined from the 1970s and started to recover in 2002, as a result of atmospheric circulation adjustment caused by the differential surface warming between Asian high latitudes and low latitudes.The climate changes over the TP have changed energy and water cycles and has thus reshaped the local environment. Thermal forcing over the TP has weakened. The warming and decrease in wind speed lowered the Bowen ratio and has led to less surface sensible heating. Atmospheric radiative cooling has been enhanced, mainly through outgoing longwave emission from the warming planetary system and slightly enhanced solar radiation reflection. The trend in both energy terms has contributed to the weakening of thermal forcing over the Plateau. The water cycle has been significantly altered by the climate changes. The monsoon-impacted region (i.e., the southern and eastern regions of the TP) has received less precipitation, more evaporation, less soil moisture and less runoff, which has resulted in the general shrinkage of lakes and pools in this region, although glacier melt has increased. The region dominated by westerlies (i.e., central, northern and western regions of the TP) received more precipitation, more evaporation, more soil moisture and more runoff, which together with more glacier melt resulted in the general expansion of lakes in this region. The overall wetting in the TP is due to both the warmer and moister conditions at the surface, which increased convective available potential energy and may eventually depend on decadal variability of atmospheric circulations such as Atlantic Multi-decadal Oscillation and an intensified Siberian High. The drying process in the southern region is perhaps related to the expansion of Hadley circulation. All these processes have not been well understood.
Capítulos de libros sobre el tema "Interactions surface troposphère"
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Bohren, Craig F. y Bruce A. Albrecht. "Ideal Gas Law". En Atmospheric Thermodynamics, 60–143. 2a ed. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780198872702.003.0002.
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Abstract The kinetic theory of gases established that invisible gas molecules are ceaselessly and rapidly moving. Gas pressure is a momentum flux density measured by interaction with surfaces. Motion does not cease at absolute zero because at sufficiently low temperatures all real gases liquefy. By definition the internal energy of an ideal gas is independent of density. Air is mostly empty space. Intermolecular collisions ensure local thermodynamic equilibrium and determine mean free paths of at least thirty molecular diameters. Molecular speeds are distributed about a mean, a decrease of about 7% corresponding to a temperature drop from 20∘C to −20∘C. Relatively fewer molecules drive chemical reactions. Even fewer molecules have sufficient energy to escape Earth’s gravity. Pressure and density decrease exponentially with height in the troposphere with a scale height of around 8 km because of gravity. Earth’s atmosphere is well-mixed up to about 100 km.
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Emanuel, Kerry A. "Deep Convective Regimes". En Atmospheric Convection, 163–487. Oxford University PressNew York, NY, 1994. http://dx.doi.org/10.1093/oso/9780195066302.003.0014.
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Abstract Over some tropical regions and middle-latitude continents during the warmer part of the year, deep convective clouds dominate the thermodynamic structure of the atmosphere. Unlike trade cumuli, deep convection is associated with plentiful precipitation and, therefore, a net release of latent heat integrated through the depth of the troposphere. Consequently, deep convection has strong effects on the dynamics and thermodynamics of the atmospheric circulation systems in which it is embedded. In Chapters 9 and 10, we discussed the local properties of precipitating moist convection, and regarded the clouds as a response to the (given) instability of a thermodynamic sounding. In Section 11.2, however, we pointed out that the global characteristics of moist convecting atmospheres are determined by the destabilization of such atmospheres by large-scale processes such as surface fluxes and radiation and not directly by the character of soundings, which is determined as a response to the forcing. As in stratocumulus and trade-cumulus boundary layers, the vertical structure of density in deep convecting atmospheres represents a compromise between the large scale processes, tending to destabilize the atmosphere to convection, and the convection itself, which tends to restore stable or neutral conditions. In this chapter we examine the global characteristics of atmospheres experiencing deep convection, as well as the character of the forcing of deep convection, and explore the nature of the interaction of ensembles of deep convective clouds with large-scale atmospheric circulations.
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Calvert, Jack G., John J. Orlando, William R. Stockwell y Timothy J. Wallington. "The Impact of Inorganic Trace Gases on Ozone in the Atmosphere". En The Mechanisms of Reactions Influencing Atmospheric Ozone. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190233020.003.0010.
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A major focus of the previous six chapters has been on the chemistry and interactions of the HOx, NOx, and volatile organic compound (VOC) families. Details of the reactions of O3 NO3, and HO that act to initiate VOC oxidation have been presented, as has the ensuing chemistry involving organic peroxy and alkoxy radicals and their interactions with NOx. In this chapter, we complete our discussion of thermal chemical reactions that impact tropospheric ozone. The chapter begins with a discussion of the budgets of two simple (inorganic) carbon-containing species not yet discussed, carbon dioxide (CO2) and carbon monoxide (CO). Although CO2 is not directly involved in ozone-related tropospheric chemistry, it is of course the species most critical to discussions of global climate change, and thus a very brief overview of its concentrations, sources, and sinks is presented. CO is a ubiquitous global pollutant, and its reaction with HO is an essential part of the tropospheric background chemistry. This is followed by a presentation of the tropospheric chemistry of halogen species, beginning with a discussion of inorganic halogen cycles that impact (in particular) the ozone chemistry of the marine boundary layer (MBL) and concluding with a detailed presentation of the reactions of Cl atoms and Br atoms with VOC species. The chapter concludes with an overview of tropospheric sulfur chemistry. The reactions leading to the oxidation of inorganic (SO2 and SO3) as well as organic sulfur compounds (e.g., DMS, CH3SCH3) are detailed, and a brief discussion of the effects of the oxidation of sulfur species on aerosol production in the troposphere and stratosphere is also given. The abundance of CO2 in the atmosphere has obviously received a great deal of attention in recent decades due to the influence of this gas on Earth’s climate system. Indeed, changes in the atmospheric CO2 concentration represent the single largest contributor to changes in radiative forcing since preindustrial times (c. 1750). The atmospheric burden of CO2 is controlled by the processes that make up the global carbon cycle—the exchanges of carbon (mostly in the form of CO2) between various “reservoirs,” including the atmosphere, land (vegetation and soil), the surface ocean, the intermediate and deep ocean, sediment on the ocean floor, and the fossil fuel reservoir (IPCC, 2007).
Actas de conferencias sobre el tema "Interactions surface troposphère"
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Stevens, T. D., S. Maruvada, T. J. Kane y C. R. Philbrick. "Lidar Observations of Mt. Pinatubo Aerosols: Effects on the Global Radiation Budget". En Optical Remote Sensing of the Atmosphere. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/orsa.1993.thb.5.
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Significant amounts of stratospheric aerosols can cause a cooling of the earth's surface due to the scattering of solar radiation back into space. Likewise a warming of the stratosphere where the particles reside will occur due to absorption of upwelling infrared radiation [1]. The eruption of the Pinatubo volcano in the Philippines (15.14°N, 120.35°E) on June 15, 1991, produced the largest impact on the stratosphere ever observed by modem airborne, spaceborne, and ground-based scientific instruments. The volcanic aerosols were ejected into the upper troposphere and the stratosphere to heights above 33 km. Due to their long residence time, the volcanic aerosols were transported around the globe in about three weeks [2]. The effects are spread in the meridional direction by the interactions of large scale planetary waves with the resivour regions about the equator. By September 27 small amounts were observed as far north as Norway.
Informes sobre el tema "Interactions surface troposphère"
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Wilson, D., Michael Shaw, Vladimir Ostashev, Michael Muhlestein, Ross Alter, Michelle Swearingen y Sarah McComas. Numerical modeling of mesoscale infrasound propagation in the Arctic. Engineer Research and Development Center (U.S.), octubre de 2022. http://dx.doi.org/10.21079/11681/45788.
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The impacts of characteristic weather events and seasonal patterns on infrasound propagation in the Arctic region are simulated numerically. The methodology utilizes wide-angle parabolic equation methods for a windy atmosphere with inputs provided by radiosonde observations and a high-resolution reanalysis of Arctic weather. The calculations involve horizontal distances up to 200 km for which interactions with the troposphere and lower stratosphere dominate. Among the events examined are two sudden stratospheric warmings, which are found to weaken upward refraction by temperature gradients while creating strongly asymmetric refraction from disturbances to the circumpolar winds. Also examined are polar low events, which are found to enhance negative temperature gradients in the troposphere and thus lead to strong upward refraction. Smaller-scale and topographically driven phenomena, such as low-level jets, katabatic winds, and surface-based temperature inversions, are found to create frequent surface-based ducting out to 100 km. The simulations suggest that horizontal variations in the atmospheric profiles, in response to changing topography and surface property transitions, such as ice boundaries, play an important role in the propagation.