Articoli di riviste: "Atmospheric physics Water vapor"

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Vaquero-Martínez, Javier, e Manuel Antón. "Review on the Role of GNSS Meteorology in Monitoring Water Vapor for Atmospheric Physics". Remote Sensing 13, n. 12 (11 giugno 2021): 2287. http://dx.doi.org/10.3390/rs13122287.

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After 30 years since the beginning of the Global Positioning System (GPS), or, more generally, Global Navigation Satellite System (GNSS) meteorology, this technique has proven to be a reliable method for retrieving atmospheric water vapor; it is low-cost, weather independent, with high temporal resolution and is highly accurate and precise. GNSS ground-based networks are becoming denser, and the first stations installed have now quite long time-series that allow the study of the temporal features of water vapor and its relevant role inside the climate system. In this review, the different GNSS methodologies to retrieve atmospheric water vapor content re-examined, such as tomography, conversion of GNSS tropospheric delay to water vapor estimates, analyses of errors, and combinations of GNSS with other sources to enhance water vapor information. Moreover, the use of these data in different kinds of studies is discussed. For instance, the GNSS technique is commonly used as a reference tool for validating other water vapor products (e.g., radiosounding, radiometers onboard satellite platforms or ground-based instruments). Additionally, GNSS retrievals are largely used in order to determine the high spatio-temporal variability and long-term trends of atmospheric water vapor or in models with the goal of determining its notable influence on the climate system (e.g., assimilation in numerical prediction, as input to radiative transfer models, study of circulation patterns, etc.).

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Bragg, S. L., e J. D. Kelley. "Atmospheric water vapor absorption at 13 μm". Applied Optics 26, n. 3 (1 febbraio 1987): 506. http://dx.doi.org/10.1364/ao.26.000506.

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Cormier, John G., Joseph T. Hodges e James R. Drummond. "Infrared water vapor continuum absorption at atmospheric temperatures". Journal of Chemical Physics 122, n. 11 (15 marzo 2005): 114309. http://dx.doi.org/10.1063/1.1862623.

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Phokate, S. "Atmospheric water vapor: Distribution and Empirical estimation in the atmosphere of Thailand". Journal of Physics: Conference Series 901 (settembre 2017): 012051. http://dx.doi.org/10.1088/1742-6596/901/1/012051.

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Gettelman, A., e Q. Fu. "Observed and Simulated Upper-Tropospheric Water Vapor Feedback". Journal of Climate 21, n. 13 (1 luglio 2008): 3282–89. http://dx.doi.org/10.1175/2007jcli2142.1.

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Abstract Satellite measurements from the Atmospheric Infrared Sounder (AIRS) in the upper troposphere over 4.5 yr are used to assess the covariation of upper-tropospheric humidity and temperature with surface temperatures, which can be used to constrain the upper-tropospheric moistening due to the water vapor feedback. Results are compared to simulations from a general circulation model, the NCAR Community Atmosphere Model (CAM), to see if the model can reproduce the variations. Results indicate that the upper troposphere maintains nearly constant relative humidity for observed perturbations to ocean surface temperatures over the observed period, with increases in temperature ∼1.5 times the changes at the surface, and corresponding increases in water vapor (specific humidity) of 10%–25% °C−1. Increases in water vapor are largest at pressures below 400 hPa, but they have a double peak structure. Simulations reproduce these changes quantitatively and qualitatively. Agreement is best when the model is sorted for satellite sampling thresholds. This indicates that the model reproduces the moistening associated with the observed upper-tropospheric water vapor feedback. The results are not qualitatively sensitive to model resolution or model physics.

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Querel, Richard R., e David A. Naylor. "Lunar absorption spectrophotometer for measuring atmospheric water vapor". Applied Optics 50, n. 4 (26 gennaio 2011): 447. http://dx.doi.org/10.1364/ao.50.000447.

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Kämpfer, N., B. Deuber, D. Feist, D. Gerber, C. Mätzler, L. Martin, J. Morland e V. Vasic. "Microwave remote sensing of water vapor in the atmosphere". Geographica Helvetica 58, n. 2 (30 giugno 2003): 81–89. http://dx.doi.org/10.5194/gh-58-81-2003.

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Abstract. Water vapor in the atmosphere plays a crucial role in climate and in atmospheric processes. Due to its long chemical lifetime it can be used as a tracer for investigations of dynamical processes in the middle atmosphere. Microwave radiometry is one of the few remote sensing methods which is capable of inferring Information on the water vapor content of the troposphere to the mesosphere, however with a different altitude resolution. Different microwave radiometers that can be operated from the ground and from an airborne platform have been built at the Institute of Applied Physics, University of Berne. The paper presents the method of microwave remote sensing and gives an overview of recently achieved results with regard to water vapor distribution as a function of altitude and Iatitude. First results of an imaging radiometer for the two dimensional distribution of liquid water is presented.

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Wu, You, Feng Zhang, Kun Wu, Min Min, Wenwen Li e Renqiang Liu. "Best Water Vapor Information Layer of Himawari-8-Based Water Vapor Bands over East Asia". Sensors 20, n. 8 (23 aprile 2020): 2394. http://dx.doi.org/10.3390/s20082394.

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The best water vapor information layer (BWIL), based on Himawari-8 water vapor bands over a typical region of East Asia, is investigated with the U.S. standard atmospheric profile and European Centre for Medium-Range Weather Forecasts Re-Analysis-interim (ERA-interim) dataset. The sensitivity tests reveal that the height of the BWIL is connected heavily to the amount of water vapor in the atmosphere, and to the satellite zenith angle. According to the temporal and spatial distribution analysis of BWIL, there are two basic features of BWIL. First, it lifts from January to July gradually and descends from July to October in the whole region. Second, it is higher over sea than land. These characteristics may stem from the transport of water vapor by monsoon and the concentration of water vapor in different areas. With multiple water vapor absorption IR bands, Himawari-8 can present water vapor information at multiple pressure layers. The water vapor content of ERA-interim in July 2016 is assessed as an example. By comparing the brightness temperatures from satellite observation and simulation under clear sky conditions, the ERA-interim reanalysis dataset may underestimate the amount of water vapor at pressure layers higher than 280 hPa and overestimate the water vapor quantity at pressure layers from 394 to 328 hPa, yet perform well at 320~260 hPa during this month.

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Zhang, Tao, Martin P. Hoerling, Judith Perlwitz, De-Zheng Sun e Donald Murray. "Physics of U.S. Surface Temperature Response to ENSO". Journal of Climate 24, n. 18 (15 settembre 2011): 4874–87. http://dx.doi.org/10.1175/2011jcli3944.1.

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Abstract To elucidate physical processes responsible for the response of U.S. surface temperatures to El Niño–Southern Oscillation (ENSO), the surface energy balance is diagnosed from observations, with emphasis on the role of clouds, water vapor, and land surface properties associated with snow cover and soil moisture. Results for the winter season (December–February) indicate that U.S. surface temperature conditions associated with ENSO are determined principally by anomalies in the surface radiative heating—the sum of absorbed solar radiation and downward longwave radiation. Each component of the surface radiative heating is linked with specific characteristics of the atmospheric hydrologic response to ENSO and also to feedbacks by the land surface response. During El Niño, surface warming over the northern United States is physically consistent with three primary processes: 1) increased downward solar radiation due to reduced cloud optical thickness, 2) reduced reflected solar radiation due to an albedo decline resulting from snow cover loss, and 3) increased downward longwave radiation linked to an increase in precipitable water. In contrast, surface cooling over the southern United States during El Niño is mainly the result of a reduction in incoming solar radiation resulting from increased cloud optical thickness. During La Niña, surface warming over the central United States results mainly from snow cover losses, whereas warming over the southern United States results mainly from a reduction in cloud optical thickness that yields increased incoming solar radiation and also from an increase in precipitable water that enhances the downward longwave radiation. For both phases of ENSO the surface radiation budget is closely linked to large-scale horizontal and vertical motions in the free atmosphere through two main processes: 1) the convergence of the atmospheric water vapor transport that largely determines cloud optical thickness and thereby affects incoming shortwave radiation and 2) the changes in tropospheric column temperature resulting from the characteristic atmospheric teleconnections that largely determine column precipitable water and thereby affect downward longwave radiation.

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De Freitas, Rose Ane Pereira, Ronald Buss Souza, Rafael Reis e Douglas Lindemann. "Relação entre o Vapor D’Água Atmosférico e a Temperatura da Superfície do Mar Sobre a Região da Confluência Brasil-Malvinas, com Base em Dados Coletados In Situ (Relationship between Atmospheric Water Vapor Content and the Sea Surface Temperature in the Brazil-Malvinas Confluence considering Data Collected In Situ)". Revista Brasileira de Geografia Física 12, n. 5 (28 giugno 2019): 1687. http://dx.doi.org/10.26848/rbgf.v12.5.p1687-1702.

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A atmosfera consiste em um dos menores reservatórios de água do planeta, contribuindo com 0,001% da massa total da água presente, porém, sendo de fundamental importância para os processos físicos na atmosfera. A partir de dados obtidos através de 130 perfis de radiossondas realizados durante dez cruzeiros oceanográficos nos meses de outubro e novembro, entre 2004 e 2015, analisa-se a influência dos gradientes de temperatura da superfície do mar (TSM) e a passagem de sistemas atmosféricos transientes na variabilidade espaço-temporal da concentração de vapor d’água da camada limite atmosférica marinha (CLAM), sobre a região da Confluência Brasil Malvinas (CBM), enfatizando-se a Operação Antártica 31 (OP31). Os dados de vapor d’água são obtidos calculando-se umidade específica em superfície e água precipitável dentro da camada limite atmosférica. Os resultados mostram que os gradientes térmicos entre as águas quentes da Corrente do Brasil (CB) e as águas frias da Corrente das Malvinas (CM) produzem diferenças significativas no conteúdo de vapor d'água da CLAM nos dois lados da frente oceanográfica. Na superfície, o valor médio da umidade específica sobre o lado quente (frio) foi 8,4 ± 1,67 mm (7,08 ± 1,51 mm). A CLAM foi localmente modulada pela TSM, sendo cerca de 2g/kg mais úmida sobre a região quente da frente oceanográfica em relação à região fria. Em todas as observações realizadas, o vapor d’água integrado na CLAM foi diretamente influenciada pela passagem de sistemas atmosféricos transiente. A B S T R A C TThe atmosphere is the smallest contributor of the planet's water tanks, providing only 0.001% of the water total mass, however, it is of fundamental importance for playing a key role in the atmosphere's physical processes. The data were obtained from 130 radiosondes profiles taken during ten oceanographic cruises carried out during the months of October and November between 2004 and 2015, analyzed the influence of the sea surface temperature (SST) gradients and the passage of transient atmospheric systems at the spatial-temporal variability of the water vapor concentration within the marine atmospheric boundary layer (MABL), over Brazil-Malvinas Confluence (BMC), emphasizing the Antarctic Operation 31 (AO31). Water vapor data are obtained by calculating surface specific moisture and precipitable water within the atmospheric boundary layer. The results show that the thermal gradients between the warm waters of Brazil Current and the cold waters of the Malvinas Current were able to produce significant differences in the water vapor content of the MABL on both sides of the oceanographic front. On the surface, the average of the specific humidity over the warm (cold) side was 8.4 ± 1.67 mm (7.08 ± 1.51 mm). The MABL was locally modulated by the SST, being about 2 g/kg wetter over the warm part of the front with respect to the cold one. In all the observations made, the water vapor integrated in the MABL was directly influenced by the passage of transient atmospheric systems.Key words: Southwest Atlantic; Oceanographic front; Transient atmospheric system

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11

Gilmore, James B. "Understanding the Influence of Measurement Uncertainty on the Atmospheric Transition in Rainfall and Column Water Vapor". Journal of the Atmospheric Sciences 72, n. 5 (1 maggio 2015): 2041–54. http://dx.doi.org/10.1175/jas-d-14-0211.1.

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Abstract Measurement uncertainty plays a key role in understanding physical relationships. This is particularly the case near phase transitions where order parameters undergo fast changes and display large variability. Here the proposed atmospheric continuous phase transition is examined by analyzing uncertainty in rain-rate and column water vapor measurements from the Tropical Rainfall Measuring Mission and through an idealized error analysis. It is shown through both of these approaches that microwave rain-rate retrievals can mimic a continuous phase transition. This occurs because microwave retrievals of instantaneous rain rates have a suppressed range. This work also suggests that column water vapor noise may provide part of the plateau seen in the observational relationship. Using updated measurements, this work indicates that the atmosphere is unlikely to undergo a continuous phase transition in rain rate but, instead, contains much larger variability in rain rates at extreme column water vapor values than previously thought. This implies that the atmosphere transitions from a low-variance nonraining state to a high-variance raining state at extreme column water vapor values.

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Trenberth, Kevin E., e Lesley Smith. "The Mass of the Atmosphere: A Constraint on Global Analyses". Journal of Climate 18, n. 6 (15 marzo 2005): 864–75. http://dx.doi.org/10.1175/jcli-3299.1.

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Abstract The total mass of the atmosphere varies mainly from changes in water vapor loading; the former is proportional to global mean surface pressure and the water vapor component is computed directly from specific humidity and precipitable water using the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analyses (ERA-40). Their difference, the mass of the dry atmosphere, is estimated to be constant for the equivalent surface pressure to within 0.01 hPa based on changes in atmospheric composition. Global reanalyses satisfy this constraint for monthly means for 1979–2001 with a standard deviation of 0.065 hPa. New estimates of the total mass of the atmosphere and its dry component, and their corresponding surface pressures, are larger than previous estimates owing to new topography of the earth’s surface that is 5.5 m lower for the global mean. Global mean total surface pressure is 985.50 hPa, 0.9 hPa higher than previous best estimates. The total mean mass of the atmosphere is 5.1480 × 1018 kg with an annual range due to water vapor of 1.2 or 1.5 × 1015 kg depending on whether surface pressure or water vapor data are used; this is somewhat smaller than the previous estimate. The mean mass of water vapor is estimated as 1.27 × 1016 kg and the dry air mass as 5.1352 ± 0.0003 × 1018 kg. The water vapor contribution varies with an annual cycle of 0.29-hPa, a maximum in July of 2.62 hPa, and a minimum in December of 2.33 hPa, although the total global surface pressure has a slightly smaller range. During the 1982/83 and 1997/98 El Niño events, water vapor amounts and thus total mass increased by about 0.1 hPa in surface pressure or 0.5 × 1015 kg for several months. Some evidence exists for slight decreases following the Mount Pinatubo eruption in 1991 and also for upward trends associated with increasing global mean temperatures, but uncertainties due to the changing observing system compromise the evidence. The physical constraint of conservation of dry air mass is violated in the reanalyses with increasing magnitude prior to the assimilation of satellite data in both ERA-40 and the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalyses. The problem areas are shown to occur especially over the Southern Oceans. Substantial spurious changes are also found in surface pressures due to water vapor, especially in the Tropics and subtropics prior to 1979.

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Wang, Yingxin, Zhiqiang Chen, Ziran Zhao, Li Zhang, Kejun Kang e Yan Zhang. "Restoration of terahertz signals distorted by atmospheric water vapor absorption". Journal of Applied Physics 105, n. 10 (15 maggio 2009): 103105. http://dx.doi.org/10.1063/1.3129308.

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St-Pierre, Médéric, e Julie M. Thériault. "Clarification of the Water Saturation Represented on Ice Crystal Growth Diagrams". Journal of the Atmospheric Sciences 72, n. 7 (luglio 2015): 2608–11. http://dx.doi.org/10.1175/jas-d-14-0357.1.

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It has been known for a long time that the shape of ice crystals depends on both the air temperature and the relative humidity of the environment. The relationships among these factors have been summarized in classification diagrams and are intensively referred to in the cloud physics literature. To put in perspective the atmospheric conditions in which the different ice crystal habits grow with respect to the level of saturation in the atmosphere, the vapor density excess and supersaturation with respect to ice at liquid water saturation have been included on those diagrams as a function of air temperature. Over the years, the definition of the water saturation included in those types of diagrams has been misdefined. The goal of this study is to show that an error has been introduced in the definition of the excess of water vapor with respect to ice.

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Makarieva, A. M., V. G. Gorshkov, D. Sheil, A. D. Nobre e B. L. Li. "Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics". Atmospheric Chemistry and Physics 13, n. 2 (25 gennaio 2013): 1039–56. http://dx.doi.org/10.5194/acp-13-1039-2013.

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Abstract. Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 °C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power – this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

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Makarieva, A. M., V. G. Gorshkov, D. Sheil, A. D. Nobre e B. L. Li. "Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics". Atmospheric Chemistry and Physics Discussions 10, n. 10 (15 ottobre 2010): 24015–52. http://dx.doi.org/10.5194/acpd-10-24015-2010.

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Abstract. Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 °C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power – this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

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Senba, Hikaru, Haruka Suzuki e Hirotaka Toyoda. "Atmospheric pressure water-vapor plasma in an air-shielded environment by water flow". Japanese Journal of Applied Physics 58, SA (4 dicembre 2018): SAAC05. http://dx.doi.org/10.7567/1347-4065/aaeb3d.

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Yufeng, Wang, Wang Qing e Hua Dengxin. "Preliminary exploration of atmospheric water vapor, liquid water and ice water by ultraviolet Raman lidar". Optics Express 27, n. 25 (27 novembre 2019): 36311. http://dx.doi.org/10.1364/oe.27.036311.

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Slocum, David M., Elizabeth J. Slingerland, Robert H. Giles e Thomas M. Goyette. "Atmospheric absorption of terahertz radiation and water vapor continuum effects". Journal of Quantitative Spectroscopy and Radiative Transfer 127 (settembre 2013): 49–63. http://dx.doi.org/10.1016/j.jqsrt.2013.04.022.

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Sun You-Wen, Liu Wen-Qing, Xie Pin-Hua, Chan Ka-Lok, Zeng Yi, Xu Jin, Li Ang, Si Fu-Qi e Li Xian-Xin. "Measurement of atmospheric water vapor using infrared differential optical absorption spectroscopy". Acta Physica Sinica 61, n. 14 (2012): 140705. http://dx.doi.org/10.7498/aps.61.140705.

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Marshak, A., Y. Knyazikhin, J. C. Chiu e W. J. Wiscombe. "Spectrally Invariant Approximation within Atmospheric Radiative Transfer". Journal of the Atmospheric Sciences 68, n. 12 (1 dicembre 2011): 3094–111. http://dx.doi.org/10.1175/jas-d-11-060.1.

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Abstract Certain algebraic combinations of single scattering albedo and solar radiation reflected from, or transmitted through, vegetation canopies do not vary with wavelength. These “spectrally invariant relationships” are the consequence of wavelength independence of the extinction coefficient and scattering phase function in vegetation. In general, this wavelength independence does not hold in the atmosphere, but in cloud-dominated atmospheres the total extinction and total scattering phase function vary only weakly with wavelength. This paper identifies the atmospheric conditions under which the spectrally invariant approximation can accurately describe the extinction and scattering properties of cloudy atmospheres. The validity of the assumptions and the accuracy of the approximation are tested with 1D radiative transfer calculations using publicly available radiative transfer models: Discrete Ordinate Radiative Transfer (DISORT) and Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART). It is shown for cloudy atmospheres with cloud optical depth above 3, and for spectral intervals that exclude strong water vapor absorption, that the spectrally invariant relationships found in vegetation canopy radiative transfer are valid to better than 5%. The physics behind this phenomenon, its mathematical basis, and possible applications to remote sensing and climate are discussed.

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Hardiman, Steven C., Ian A. Boutle, Andrew C. Bushell, Neal Butchart, Mike J. P. Cullen, Paul R. Field, Kalli Furtado et al. "Processes Controlling Tropical Tropopause Temperature and Stratospheric Water Vapor in Climate Models". Journal of Climate 28, n. 16 (10 agosto 2015): 6516–35. http://dx.doi.org/10.1175/jcli-d-15-0075.1.

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Abstract A warm bias in tropical tropopause temperature is found in the Met Office Unified Model (MetUM), in common with most models from phase 5 of CMIP (CMIP5). Key dynamical, microphysical, and radiative processes influencing the tropical tropopause temperature and lower-stratospheric water vapor concentrations in climate models are investigated using the MetUM. A series of sensitivity experiments are run to separate the effects of vertical advection, ice optical and microphysical properties, convection, cirrus clouds, and atmospheric composition on simulated tropopause temperature and lower-stratospheric water vapor concentrations in the tropics. The numerical accuracy of the vertical advection, determined in the MetUM by the choice of interpolation and conservation schemes used, is found to be particularly important. Microphysical and radiative processes are found to influence stratospheric water vapor both through modifying the tropical tropopause temperature and through modifying upper-tropospheric water vapor concentrations, allowing more water vapor to be advected into the stratosphere. The representation of any of the processes discussed can act to significantly reduce biases in tropical tropopause temperature and stratospheric water vapor in a physical way, thereby improving climate simulations.

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Hottovy, Scott, e Samuel N. Stechmann. "A Spatiotemporal Stochastic Model for Tropical Precipitation and Water Vapor Dynamics". Journal of the Atmospheric Sciences 72, n. 12 (24 novembre 2015): 4721–38. http://dx.doi.org/10.1175/jas-d-15-0119.1.

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Abstract A linear stochastic model is presented for the dynamics of water vapor and tropical convection. Despite its linear formulation, the model reproduces a wide variety of observational statistics from disparate perspectives, including (i) a cloud cluster area distribution with an approximate power law; (ii) a power spectrum of spatiotemporal red noise, as in the “background spectrum” of tropical convection; and (iii) a suite of statistics that resemble the statistical physics concepts of critical phenomena and phase transitions. The physical processes of the model are precipitation, evaporation, and turbulent advection–diffusion of water vapor, and they are represented in idealized form as eddy diffusion, damping, and stochastic forcing. Consequently, the form of the model is a damped version of the two-dimensional stochastic heat equation. Exact analytical solutions are available for many statistics, and numerical realizations can be generated for minimal computational cost and for any desired time step. Given the simple form of the model, the results suggest that tropical convection may behave in a relatively simple, random way. Finally, relationships are also drawn with the Ising model, the Edwards–Wilkinson model, the Gaussian free field, and the Schramm–Loewner evolution and its possible connection with cloud cluster statistics. Potential applications of the model include several situations where realistic cloud fields must be generated for minimal cost, such as cloud parameterizations for climate models or radiative transfer models.

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Huang, Wei, Song Feng, Jianhui Chen e Fahu Chen. "Physical Mechanisms of Summer Precipitation Variations in the Tarim Basin in Northwestern China". Journal of Climate 28, n. 9 (1 maggio 2015): 3579–91. http://dx.doi.org/10.1175/jcli-d-14-00395.1.

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Abstract The Tarim basin (TB) in northwestern China is one of the most arid regions in the middle latitudes, where water is scarce year-round. This study investigates the variations of summer precipitation in the TB and their association with water vapor fluxes and atmospheric circulation. The results suggest that the variations of summer precipitation in the TB are dominated by the water vapor fluxes from the south and east, although the long-term mean water vapor mostly comes from the west. The anomalous water vapor fluxes are closely associated with the meridional teleconnection pattern around 50°–80°E and the zonal teleconnection pattern along the Asian westerly jet in summer. The meridional teleconnection connects central Asia and the tropical Indian Ocean; the zonal teleconnection resembles the “Silk Road pattern.” The two teleconnections lead to negative height anomalies in central Asia and positive height anomalies in the Arabian Sea and India and in northern central China. The anomalous pressure gradient force, caused by these height anomalies, leads to anomalous ascending motion in the TB and brings low-level moisture along the eastern periphery of the Tibetan Plateau and water vapor from the Arabian Sea passing over the Tibetan Plateau to influence precipitation development in the study region.

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Bruneau, D., H. Cazeneuve, C. Loth e J. Pelon. "Double-pulse dual-wavelength alexandrite laser for atmospheric water vapor measurement". Applied Optics 30, n. 27 (20 settembre 1991): 3930. http://dx.doi.org/10.1364/ao.30.003930.

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AKATA, Naofumi, Hideki KAKIUCHI, Masahiro TANAKA, Nagayoshi SHIMA, Yoshitaka SHIROMA, Shinji TOKONAMI, Masahiro HOSODA, Yoshio ISHIKAWA, Masahide FURUKAWA e Tetsuya SANADA. "Development of Rapid Sampling System of Atmospheric Water Vapor for Tritium Measurement". Plasma and Fusion Research 13 (12 giugno 2018): 3405064. http://dx.doi.org/10.1585/pfr.13.3405064.

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Clark, Spencer K., Yi Ming, Isaac M. Held e Peter J. Phillipps. "The Role of the Water Vapor Feedback in the ITCZ Response to Hemispherically Asymmetric Forcings". Journal of Climate 31, n. 9 (maggio 2018): 3659–78. http://dx.doi.org/10.1175/jcli-d-17-0723.1.

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In comprehensive and idealized general circulation models, hemispherically asymmetric forcings lead to shifts in the latitude of the intertropical convergence zone (ITCZ). Prior studies using comprehensive GCMs (with complicated parameterizations of radiation, clouds, and convection) suggest that the water vapor feedback tends to amplify the movement of the ITCZ in response to a given hemispherically asymmetric forcing, but this effect has yet to be elucidated in isolation. This study uses an idealized moist model, coupled to a full radiative transfer code, but without clouds, to examine the role of the water vapor feedback in a targeted manner. In experiments with interactive water vapor and radiation, the ITCZ latitude shifts roughly twice as much off the equator as in cases with the water vapor field seen by the radiation code prescribed to a static hemisperically symmetric control distribution. Using energy flux equator theory for the latitude of the ITCZ, the amplification of the ITCZ shift is attributed primarily to the longwave water vapor absorption associated with the movement of the ITCZ into the warmer hemisphere, further increasing the net column heating asymmetry. Local amplification of the imposed forcing by the shortwave water vapor feedback plays a secondary role. Experiments varying the convective relaxation time, an important parameter in the convection scheme used in the idealized moist model, yield qualitatively similar results, suggesting some degree of robustness to the model physics; however, the sensitivity experiments do not preclude that more extreme modifications to the convection scheme could lead to qualitatively different behavior.

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28

Azam, F., K. Bramstedt, A. Rozanov, K. Weigel, H. Bovensmann, G. P. Stiller e J. P. Burrows. "SCIAMACHY lunar occultation water vapor measurements: retrieval and validation results". Atmospheric Measurement Techniques 5, n. 10 (24 ottobre 2012): 2499–513. http://dx.doi.org/10.5194/amt-5-2499-2012.

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Abstract. SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) lunar occultation measurements have been used to derive vertical profiles of stratospheric water vapor for the Southern Hemisphere in the near infrared (NIR) spectral range of 1350–1420 nm. The focus of this study is to present the retrieval methodology including the sensitivity studies and optimizations for the implementation of the radiative transfer model on SCIAMACHY lunar occultation measurements. The study also includes the validation of the data product with the collocated measurements from two satellite occultation instruments and two instruments measuring in limb geometry. The SCIAMACHY lunar occultation water vapor measurement comparisons with the ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) instrument have shown an agreement of 5% on the average that is well within the reported biases of ACE in the stratosphere. The comparisons with HALOE (Halogen Occultation Experiment) have also shown good results where the agreement between the instruments is within 5%. The validations of the lunar occultation water vapor measurements with MLS (Microwave Limb Sounder) instrument are exceptionally good, varying between 1.5 to around 4%. The validations with MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) are in the range of 10%. A validated dataset of water vapor vertical distributions from SCIAMACHY lunar occultation measurements is expected to facilitate the understanding of physical and chemical processes in the southern mid-latitudes and the dynamical processes related to the polar vortex.

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29

Lebedev, Yurii, Alekcey Tatarinov, Irina Epstein e Alexander Titov. "Features of processes in a microwave discharge in water vapor". Applied Physics, n. 3 (8 luglio 2021): 5–10. http://dx.doi.org/10.51368/1996-0948-2021-3-5-10.

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A zero-dimensional steady-state simulation of microwave discharge in water vapor at atmos-pheric and reduced pressures and a constant gas temperature has been carried out. A model of a continuous stirring reactor is used. A joint solution of the balance equations for neutral and charged plasma components, the Boltzmann equation for plasma electrons, and the equation for the stationary distribution of the microwave field in a volume filled with plasma is carried out. The dependences of various parameters of thedischarge (the magnitude of the microwave field, the concentrations of all components) on the input specific power WVare obtained. It is shown that at reduced pressure the magnitude of the microwave field in the plasma is signifi-cantly lower, and the electron concentration is higher than at atmospheric pressure at the same applied specific power. At atmospheric pressure the water plasma is electronegative, and quasi-neutrality is maintained by the negative OH-ion in the range of the considered WV values. Transition from electronegative to electropositive plasma occurs at pressure of 30 Torr and ap-plied specific power of 60–70 kW/cm3

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30

Darby, Lisa S., Allen B. White, Daniel J. Gottas e Timothy Coleman. "An Evaluation of Integrated Water Vapor, Wind, and Precipitation Forecasts Using Water Vapor Flux Observations in the Western United States". Weather and Forecasting 34, n. 6 (1 dicembre 2019): 1867–88. http://dx.doi.org/10.1175/waf-d-18-0159.1.

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Abstract Differences between forecasts and observations at eight atmospheric river observatories (AROs) in the western United States during winter 2015/16 are analyzed. NOAA’s operational RAP and HRRR 3-h forecasts of wind, integrated water vapor (IWV), integrated water vapor flux (IWV flux), and precipitation from the grid points nearest the AROs were paired with ARO observations presented in the NOAA/Physical Sciences Division’s water vapor flux tool (WVFT). The focus of this paper is to characterize and quantify the differences in the WVFT observations and forecasts. We used traditional forecast evaluation methods since they were compatible with the design of the tool: a near-real-time visual depiction of hourly observed and forecasted variables at a single location. Forecast root-mean-squared errors (RMSEs) and unbiased RMSEs, standard deviations of the observed and forecasted variables, and frequency bias scores (FBS) for all of the fields, plus equitable threat scores for precipitation, are presented. Both models forecasted IWV at all AROs and the winds that drive orographic precipitation at most AROs within a reasonable range of the observations as indicated by comparisons of the standard deviations and RMSEs of the forecasts with the standard deviations of the observations and FBS. These results indicated that forecasted advection of moisture to the stations was adequate for generating precipitation. At most stations and most hourly precipitation rates, the HRRR underpredicted precipitation. At several AROs the RAP precipitation forecasts more closely matched the observations at smaller (<1.27 mm h−1) precipitation rates, but underpredicted precipitation rates > 2 mm h−1.

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31

Porter, Jack G., Warren De Bruyn e Eric S. Saltzman. "Eddy flux measurements of sulfur dioxide deposition to the sea surface". Atmospheric Chemistry and Physics 18, n. 20 (24 ottobre 2018): 15291–305. http://dx.doi.org/10.5194/acp-18-15291-2018.

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Abstract. Deposition to the sea surface is a major atmospheric loss pathway for many important trace gases, such as sulfur dioxide (SO2). The air–sea transfer of SO2 is controlled entirely on the atmospheric side of the air–sea interface due to high effective solubility and other physical–chemical properties. There have been few direct field measurements of such fluxes due to the challenges associated with making fast-response measurements of highly soluble trace gases at very low ambient levels. In this study, we report direct eddy covariance air–sea flux measurements of SO2, sensible heat, water vapor, and momentum. The measurements were made over shallow coastal waters from the Scripps Pier, La Jolla, CA, using negative ion chemical ionization mass spectrometry as the SO2 sensor. The observed transfer velocities for SO2, sensible heat, water vapor, and momentum and their wind speed dependences indicate that SO2 fluxes can be reliably measured using this approach. As expected, the transfer velocities for SO2, sensible heat, and water vapor are lower than that for momentum, demonstrating the contribution of molecular diffusion to the overall air-side resistance to gas transfer. Furthermore, transfer velocities of SO2 were lower than those of sensible heat and water vapor when observed simultaneously. This result is attributed to diffusive resistance in the interfacial layer of the air–sea interface.

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32

Wang, Jiali, Prasanna Balaprakash e Rao Kotamarthi. "Fast domain-aware neural network emulation of a planetary boundary layer parameterization in a numerical weather forecast model". Geoscientific Model Development 12, n. 10 (10 ottobre 2019): 4261–74. http://dx.doi.org/10.5194/gmd-12-4261-2019.

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Abstract. Parameterizations for physical processes in weather and climate models are computationally expensive. We use model output from the Weather Research Forecast (WRF) climate model to train deep neural networks (DNNs) and evaluate whether trained DNNs can provide an accurate alternative to the physics-based parameterizations. Specifically, we develop an emulator using DNNs for a planetary boundary layer (PBL) parameterization in the WRF model. PBL parameterizations are used in atmospheric models to represent the diurnal variation in the formation and collapse of the atmospheric boundary layer – the lowest part of the atmosphere. The dynamics and turbulence, as well as velocity, temperature, and humidity profiles within the boundary layer are all critical for determining many of the physical processes in the atmosphere. PBL parameterizations are used to represent these processes that are usually unresolved in a typical climate model that operates at horizontal spatial scales in the tens of kilometers. We demonstrate that a domain-aware DNN, which takes account of underlying domain structure (e.g., nonlocal mixing), can successfully simulate the vertical profiles within the boundary layer of velocities, temperature, and water vapor over the entire diurnal cycle. Results also show that a single trained DNN from one location can produce predictions of wind speed, temperature, and water vapor profiles over nearby locations with similar terrain conditions with correlations higher than 0.9 when compared with the WRF simulations used as the training dataset.

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33

Chen, Zhiyuan, Lijun Wang, Ziyou Yu, Fushen Li, Zaihong Sun, Hailei Zhao e Kuo Chih Chou. "Corrosion Process of Stainless Steel 441 with Heated Steam at 1,000 °C". High Temperature Materials and Processes 36, n. 7 (26 luglio 2017): 717–24. http://dx.doi.org/10.1515/htmp-2015-0238.

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AbstractStainless steel 441 was oxidized in water vapor containing atmospheres at 1,000 °C to study the contrary effects of water vapor on the oxidization process. The steel in 3.5 vol. % H2O containing atmosphere exhibited an relatively strong protective behavior. The reason was that the densification of the chromium oxide scale was promoted due to the sintering of the oxide grains via Cr-containing species vapor. But the oxidation of the steel in 11.5 ~ 15.6 vol. % H2O containing atmosphere followed a non-protective breakaway oxidation due to the breakage of the dense scale by “bubbles” and the formation of iron-rich oxides layer. Experimental result shows that the growth stress increased about 2 GPa during the first 70 ks in wet oxidizing atmosphere. The relatively slow increase of the oxides scale growth stress could be release in water vapor containing atmosphere.

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34

Loescher, H. W., C. V. Hanson e T. W. Ocheltree. "The Psychrometric Constant Is Not Constant: A Novel Approach to Enhance the Accuracy and Precision of Latent Energy Fluxes through Automated Water Vapor Calibrations". Journal of Hydrometeorology 10, n. 5 (1 ottobre 2009): 1271–84. http://dx.doi.org/10.1175/2009jhm1148.1.

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Abstract Numerous agencies, programs, and national networks are focused on improving understanding of water and energy fluxes across temporal and spatial scales and on enhancing confidence to synthesize data across multiple sites. Enhancing the accuracy and precision in the surface energy balance and the latent energy (λE) flux lies, in part, with being able to uniformly calibrate water vapor measurements at and among sites to traceable standards. This paper examines (i) the traceable physical controls on field applications of chilled-mirror hygrometers and (ii) an automated means to accurately and precisely calibrate infrared gas analyzers for water vapor concentrations and eddy covariance (λE) data. The environmental physics and gas handling were examined in a theoretical and applied manner that found that chilled-mirror technologies can be a robust measure of dewpoint temperatures and ambient water vapor only if the unit conversions are accounted for between inlet and body temperatures. Psychrometers were also examined and a functional relationship (exponential) was developed for the psychrometric constant against the wet-bulb temperature depression (Tdb − Twb), across a wider range of temperature depressions than previously reported. These empirical estimates of the psychrometer constant for small temperature depressions are much lower than other reported values—that is, ∼0.000 52 K−1 for a wet-bulb temperature depression (Tdb − Twb) of 4.3 K.

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35

Koga, Nobuyoshi, Loic Favergeon e Satoki Kodani. "Impact of atmospheric water vapor on the thermal decomposition of calcium hydroxide: a universal kinetic approach to a physico-geometrical consecutive reaction in solid–gas systems under different partial pressures of product gas". Physical Chemistry Chemical Physics 21, n. 22 (2019): 11615–32. http://dx.doi.org/10.1039/c9cp01327j.

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36

Rodriguez-Santiago, Victor, Andres A. Bujanda, Benjamin E. Stein e Daphne D. Pappas. "Atmospheric Plasma Processing of Polymers in Helium-Water Vapor Dielectric Barrier Discharges". Plasma Processes and Polymers 8, n. 7 (20 aprile 2011): 631–39. http://dx.doi.org/10.1002/ppap.201000186.

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37

Thome, Kurtis J., Mark W. Smith, James M. Palmer e John A. Reagan. "Three-channel solar radiometer for the determination of atmospheric columnar water vapor". Applied Optics 33, n. 24 (20 agosto 1994): 5811. http://dx.doi.org/10.1364/ao.33.005811.

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38

Langhans, Wolfgang, Kyongmin Yeo e David M. Romps. "Lagrangian Investigation of the Precipitation Efficiency of Convective Clouds". Journal of the Atmospheric Sciences 72, n. 3 (24 febbraio 2015): 1045–62. http://dx.doi.org/10.1175/jas-d-14-0159.1.

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Abstract The precipitation efficiency of cumulus congestus clouds is investigated with a new Lagrangian particle framework for large-eddy simulations. The framework is designed to track particles representative of individual water molecules. A Monte Carlo approach facilitates the transition of particles between the different water classes (e.g., vapor, rain, or graupel). With this framework, it is possible to reconstruct the pathways of water as it moves from vapor at a particular altitude to rain at the surface. By tracking water molecules through both physical and microphysical space, the precipitation efficiency can be studied in detail as a function of height. Large-eddy simulations of individual cumulus congestus clouds show that the clouds convert entrained vapor to surface precipitation with an efficiency of around 10%. About two-thirds of all vapor that enters the cloud does so by entrainment in the free troposphere, but free-tropospheric vapor accounts for only one-third to one-half of the surface rainfall, with the remaining surface rainfall originating as vapor entrained through the cloud base. The smaller efficiency with which that laterally entrained water is converted into surface precipitation results from the smaller efficiencies with which it condenses, forms precipitating hydrometeors, and reaches the surface.

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39

Collette, S., T. Dufour e F. Reniers. "Reactivity of water vapor in an atmospheric argon flowing post-discharge plasma torch". Plasma Sources Science and Technology 25, n. 2 (25 febbraio 2016): 025014. http://dx.doi.org/10.1088/0963-0252/25/2/025014.

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40

Azam, F., K. Bramstedt, A. Rozanov, K. Weigel, H. Bovensmann, G. P. Stiller e J. P. Burrows. "SCIAMACHY lunar occultation water vapor measurements: retrieval and validation results". Atmospheric Measurement Techniques Discussions 5, n. 1 (3 febbraio 2012): 1029–73. http://dx.doi.org/10.5194/amtd-5-1029-2012.

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Abstract (sommario):

Abstract. SCIAMACHY lunar occultation measurements have been used to derive vertical profiles of stratospheric water vapor for the Southern Hemisphere in the near infrared (NIR) spectral range of 1350–1420 nm. The focus of this study is to present the retrieval methodology including the sensitivity studies and optimizations for the implementation of the radiative transfer model on SCIAMACHY lunar occultation measurements. The study also includes the validation of the data product with the collocated measurements from two satellite occultation instruments and two instruments measuring in limb geometry. The SCIAMACHY lunar occultation water vapor measurements comparisons with the ACE-FTS instrument have shown an agreement of 5% on the average that is well within the reported biases of ACE in the stratosphere. The comparisons with HALOE have also shown good results where the agreement between the instruments is within 5%. The validations of the lunar occultation water vapor measurements with MLS instrument are exceptionally good varying between 1.5 to around 4%. The validations with MIPAS are in the range of 10%. A validated dataset of water vapor vertical distributions from SCIAMACHY lunar occultation measurements is expected to facilitate the understanding of physical and chemical processes in the southern mid-latitudes and the dynamical processes related to polar vortex.

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41

Shell, Karen M. "Consistent Differences in Climate Feedbacks between Atmosphere–Ocean GCMs and Atmospheric GCMs with Slab-Ocean Models*". Journal of Climate 26, n. 12 (15 giugno 2013): 4264–81. http://dx.doi.org/10.1175/jcli-d-12-00519.1.

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Abstract Climate sensitivity is generally studied using two types of models. Atmosphere–ocean general circulation models (AOGCMs) include interactive ocean dynamics and detailed heat uptake. Atmospheric GCMs (AGCMs) with slab ocean models (SOMs) cannot fully simulate the ocean’s response to and influence on climate. However, AGCMs are computationally cheaper and thus are often used to quantify and understand climate feedbacks and sensitivity. Here, physical climate feedbacks are compared between AOGCMs and SOM-AGCMs from the Coupled Model Intercomparison Project phase 3 (CMIP3) using the radiative kernel technique. Both the global-average (positive) water vapor and (negative) lapse-rate feedbacks are consistently stronger in AOGCMs. Water vapor feedback differences result from an essentially constant relative humidity and peak in the tropics, where temperature changes are larger for AOGCMs. Differences in lapse-rate feedbacks extend to midlatitudes and correspond to a larger ratio of tropical- to global-average temperature changes. Global-average surface albedo feedbacks are similar between models types because of a near cancellation of Arctic and Antarctic differences. In AOGCMs, the northern high latitudes warm faster than the southern latitudes, resulting in interhemispheric differences in albedo, water vapor, and lapse-rate feedbacks lacking in the SOM-AGCMs. Meridional heat transport changes also depend on the model type, although there is a large intermodel spread. However, there are no consistent global or zonal differences in cloud feedbacks. Effects of the forcing scenario [Special Report on Emissions Scenarios A1B (SRESa1b) or the 1% CO2 increase per year to doubling (1%to2x) experiments] on feedbacks are model dependent and generally of lesser importance than the model type. Care should be taken when using SOM-AGCMs to understand AOGCM feedback behavior.

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42

BUZYKIN, O. G., A. A. IONIN, S. V. IVANOV, A. A. KOTKOV, L. V. SELEZNEV e A. V. SHUSTOV. "Resonant absorption of first-overtone CO laser radiation by atmospheric water vapor and pollutants". Laser and Particle Beams 18, n. 4 (ottobre 2000): 697–713. http://dx.doi.org/10.1017/s0263034600184113.

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Resonant absorption of first-overtone (FO) CO laser radiation by atmospheric water vapor and various organic and nonorganic pollutants is discussed. Suitable ro-vibrational lines are selected for their potential use in traditional spectroscopic schemes of atmospheric pollution diagnostics. Nonlinear atmospheric absorption of intense multiline FO CO laser radiation is simulated and laser-induced changes in absorption spectra are demonstrated. Absorption coefficients of a few substances on several FO CO ro-vibrational lines are experimentally measured. A comparative analysis of spectral characteristics of an FO CO laser and an HF (DF) laser demonstrates that the potential of FO CO laser applications for spectroscopic detection of various molecular trace gases is greater than that of HF and DF lasers.

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43

Turner, D. D., e U. Löhnert. "Information Content and Uncertainties in Thermodynamic Profiles and Liquid Cloud Properties Retrieved from the Ground-Based Atmospheric Emitted Radiance Interferometer (AERI)". Journal of Applied Meteorology and Climatology 53, n. 3 (marzo 2014): 752–71. http://dx.doi.org/10.1175/jamc-d-13-0126.1.

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AbstractThe Atmospheric Emitted Radiance Interferometer (AERI) observes spectrally resolved downwelling radiance emitted by the atmosphere in the infrared portion of the electromagnetic spectrum. Profiles of temperature and water vapor, and cloud liquid water path and effective radius for a single liquid cloud layer, are retrieved using an optimal estimation–based physical retrieval algorithm from AERI-observed radiance data. This algorithm provides a full error covariance matrix for the solution, and both the degrees of freedom for signal and the Shannon information content. The algorithm is evaluated with both synthetic and real AERI observations. The AERI is shown to have approximately 85% and 70% of its information in the lowest 2 km of the atmosphere for temperature and water vapor profiles, respectively. In clear-sky situations, the mean bias errors with respect to the radiosonde profiles are less than 0.2 K and 0.3 g kg−1 for heights below 2 km for temperature and water vapor mixing ratio, respectively; the maximum root-mean-square errors are less than 1 K and 0.8 g kg−1. The errors in the retrieved profiles in cloudy situations are larger, due in part to the scattering contribution to the downwelling radiance that was not accounted for in the forward model. Scattering is largest in one of the spectral regions used in the retrieval, however, and removing this spectral region results in a slight reduction of the information content but a considerable improvement in the accuracy of the retrieved thermodynamic profiles.

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44

Takahashi, Ken. "The Global Hydrological Cycle and Atmospheric Shortwave Absorption in Climate Models under CO2 Forcing". Journal of Climate 22, n. 21 (1 novembre 2009): 5667–75. http://dx.doi.org/10.1175/2009jcli2674.1.

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Abstract The spread among the predictions by climate models for the strengthening of the global hydrological cycle [i.e., the global mean surface latent heat flux (LH), or, equivalently, precipitation] at a given level of CO2-induced global warming is of the same magnitude as the intermodel mean. By comparing several climate models from the World Climate Research Programme (WCRP) Coupled Model Intercomparison Project phase 3 (CMIP3) database under idealized CO2 forcings, it is shown that differences in the increase in global atmospheric shortwave heating (SWabs) induced by clear-sky absorption, presumably by water vapor, partly explains this spread. The increases in SWabs and LH present similar spreads across models but are anticorrelated, so the sum SWabs + LH increases more robustly than either alone. This is consistent with a recently proposed theory (Takahashi) that predicts that this sum (or, equivalently, the net longwave divergence minus the surface sensible heat flux) is constrained by energy conservation and robust longwave physics. The intermodel scatter in SWabs changes is explained neither by differences in the radiative transfer models nor in intermodel differences in global water vapor content change, but perhaps by more subtle aspects of the changes in the water vapor distribution. Nevertheless, the fact that the radiative transfer models generally underestimate the increase in SWabs relative to the corresponding line-by-line calculation for a given change in water vapor content suggests that the climate models might be overestimating the rate of increase in the global hydrological cycle with global warming.

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45

Cheng Jiuming, 程久明, 李建玉 Li Jianyu, 崔朝龙 Cui Chaolong, 黄尧 Huang Yao, 戴聪明 Dai Congming e 黄宏华 Huang Honghua. "Simultaneous Measurement of Total Atmospheric Transmittance and Precipitable Water Vapor at Night". Acta Optica Sinica 41, n. 4 (2021): 0401003. http://dx.doi.org/10.3788/aos202141.0401003.

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46

Elgered, Gunnar, e Per O. J. Jarlemark. "Ground-based microwave radiometry and long-term observations of atmospheric water vapor". Radio Science 33, n. 3 (maggio 1998): 707–17. http://dx.doi.org/10.1029/98rs00488.

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47

Gamache, Robert R. "Lineshape parameters for water vapor in the 3.2–17.76μm region for atmospheric applications". Journal of Molecular Spectroscopy 229, n. 1 (gennaio 2005): 9–18. http://dx.doi.org/10.1016/j.jms.2004.08.004.

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48

Flury, T., S. C. Müller, K. Hocke e N. Kämpfer. "Water vapor transport in the lower mesosphere of the subtropics: a trajectory analysis". Atmospheric Chemistry and Physics 8, n. 23 (10 dicembre 2008): 7273–80. http://dx.doi.org/10.5194/acp-8-7273-2008.

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Abstract. The Institute of Applied Physics operates an airborne microwave radiometer AMSOS that measures the rotational transition line of water vapor at 183.3 GHz. Water vapor profiles are retrieved for the altitude range from 15 to 75 km along the flight track. We report on a water vapor enhancement in the lower mesosphere above India and the Arabian Sea. The measurements took place on our flight from Switzerland to Australia and back in November 2005 conducted during EC- project SCOUT-O3. We find an enhancement of up to 25% in the lower mesospheric H2O volume mixing ratio measured on the return flight one week after the outward flight. The origin of the air is traced back by means of a trajectory model in the lower mesosphere and wind fields from ECMWF. During the outward flight the air came from the Atlantic Ocean around 25 N and 40 W. On the return flight the air came from northern India and Nepal around 25 N and 90 E. Mesospheric H2O measurements from Aura/MLS confirm the transport processes of H2O derived by trajectory analysis of the AMSOS data. Thus the large variability of H2O VMR during our flight is explained by a change of the winds in the lower mesosphere. This study shows that trajectory analysis can be applied in the mesosphere and is a powerful tool to understand the large variability in mesospheric H2O.

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49

Frierson, Dargan M. W., Isaac M. Held e Pablo Zurita-Gotor. "A Gray-Radiation Aquaplanet Moist GCM. Part I: Static Stability and Eddy Scale". Journal of the Atmospheric Sciences 63, n. 10 (1 ottobre 2006): 2548–66. http://dx.doi.org/10.1175/jas3753.1.

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Abstract In this paper, a simplified moist general circulation model is developed and used to study changes in the atmospheric general circulation as the water vapor content of the atmosphere is altered. The key elements of the model physics are gray radiative transfer, in which water vapor and other constituents have no effect on radiative fluxes, a simple diffusive boundary layer with prognostic depth, and a mixed layer aquaplanet surface boundary condition. This GCM can be integrated stably without a convection parameterization, with large-scale condensation only, and this study focuses on this simplest version of the model. These simplifications provide a useful framework in which to focus on the interplay between latent heat release and large-scale dynamics. In this paper, the authors study the role of moisture in determining the tropospheric static stability and midlatitude eddy scale. In a companion paper, the effects of moisture on energy transports by baroclinic eddies are discussed. The authors vary a parameter in the Clausius–Clapeyron relation to control the amount of water in the atmosphere, and consider circulations ranging from the dry limit to 10 times a control value. The typical length scale of midlatitude eddies is found to be remarkably insensitive to the amount of moisture in the atmosphere in this model. The Rhines scale evaluated at the latitude of the maximum eddy kinetic energy fits the model results for the eddy scale well. Moist convection is important in determining the extratropical lapse rate, and the dry stability is significantly increased with increased moisture content.

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50

Albert, P., K. M. Smith, R. Bennartz, D. A. Newnham e J. Fischer. "Satellite- and ground-based observations of atmospheric water vapor absorption in the region". Journal of Quantitative Spectroscopy and Radiative Transfer 84, n. 2 (marzo 2004): 181–93. http://dx.doi.org/10.1016/s0022-4073(03)00141-9.

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