Cloud physics

Clouds are one of the most significant elements of the atmospheric system, playing several key roles  

Clouds are a major factor in the Earth s radiation budget, reflecting sunlight back to space or blanketing the lower atmosphere and trapping infrared radiation emitted by the Earth s surface. 

Clouds deliver water from the atmosphere to the Earth s surface as rain or snow and are thus a key step in the hydrologic cycle. 

Clouds scavenge gaseous and particulate materials and return them to the surface (wet deposition). 

Clouds provide a medium for aqueous-phase chemical reactions and production of secondary species. 

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Studies of the electrical and mechanical responses of ferroelectric solids under shock compression show this technical problem to be the most complex of any investigated. The combination of rate-dependent mechanical and electrical processes along with strong electromechanical coupling has clouded physical interpretation of the numerous investigations. 

Thompson, P.D., 1968. A transfomiation of the stochastic equation for droplet coalescence. In Proceedings of the international conference on cloud physics, Toronto, Canada, pp. 1115-1126. 

Atmospheric aerosols have a direct impact on earth s radiation balance, fog formation and cloud physics, and visibility degradation as well as human health effect[l]. Both natural and anthropogenic sources contribute to the formation of ambient aerosol, which are composed mostly of sulfates, nitrates and ammoniums in either pure or mixed forms[2]. These inorganic salt aerosols are hygroscopic by nature and exhibit the properties of deliquescence and efflorescence in humid air. That is, relative humidity(RH) history and chemical composition determine whether atmospheric aerosols are liquid or solid. Aerosol physical state affects climate and environmental phenomena such as radiative transfer, visibility, and heterogeneous chemistry. Here we present a mathematical model that considers the relative humidity history and chemical composition dependence of deliquescence and efflorescence for describing the dynamic and transport behavior of ambient aerosols[3]. 

Aerosol production and transport over the oceans are of interest in studies concerning cloud physics, air pollution, atmospheric optics, and air-sea interactions. However, the contribution of sea spray droplets to the transfer of moisture and latent heat from the sea to the atmosphere is not well known. In an effort to investigate these phenomena, Edson et al.[12l used an interactive Eulerian-Lagrangian approach to simulate the generation, turbulent transport and evaporation of droplets. The k-e turbulence closure model was incorporated in the Eulerian-Lagrangian model to accurately simulate... 

Pruppacher, H. R., The Role of Cloud Physics in Atmospheric Multiphase Systems Ten Basic Statements, in Chemistry of Multiphase Atmospheric Systems (W. Jaeschke, Ed.), NATO ASI Series, Vol. G6, Springer-Verlag, Berlin/New York, 1986. 

In cloud physics, coagulation is generally used synonymously with accretion. Less frequently, it refers to any process by which a cloud s numerous small cloud drops are convened into a smaller number of larger precipitation particles. When so used, the term is employed in analogy In the coagulation of any colloidal state. (See 1 above.)... 

CliC CLIVAR CLRTAP CM CO COADS COLA COP CORP CPI CPL CPR CRC CRF CRP CRS CSD CSIRO Climate and Cryosphere (CliC) project CLImate VARiability and predictability Convention on Long-Range Transboundary Air Pollution Climate Model Carbon monoxide Comprehensive Ocean-Atmosphere Data Set Center of the Ocean-Land-Atmosphere system study Conference of the Parties Chinese Ozone Research Program Consumer Price Index Cloud Physics Lidar Continuous Plankton Recorder program Chemical Rubber Company Cloud Radiative Forcing Conservation Reserve Program Cloud Radar System Commission on Sustainable Development Commonwealth Scientific and Industrial Research... 

Laboratory simulations of aqueous-phase chemical systems are necessary to 1) verify reaction mechanisms and 2) assign a value and an uncertainty to transformation rates. A dynamic cloud chemistry simulation chamber has been characterized to obtain these rates and their uncertainties. Initial experimental results exhibited large uncertainties, with a 26% variability in cloud liquid water as the major contributor to measurement uncertainty. Uncertainties in transformation rates were as high as factor of ten. Standard operating procedures and computer control of the simulation chamber decreased the variability in the observed liquid water content, experiment duration and final temperature from 0.65 to 0.10 g nr3, 180 to 5.3 s and 1.73 to 0.27°C respectively. The consequences of this improved control over the experimental variables with respect to cloud chemistry were tested for the aqueous transformation of SO2 using a cloud-physics and chemistry model of this system. These results were compared to measurements made prior to the institution of standard operating procedures and computer control to quantify the reduction in reaction rate uncertainty resulting from those controls. 

Quantify the uncertainty of gas to solute transformation rates resulting from uncertainty in the control of the cloud-physical parameters. 

Several areas in which chemical measurement technologies have become available and/or refined for airborne applications have been reviewed in this paper. It is a selective review and many important meteorological and cloud physics measurement capabilities of relevance to atmospheric chemistry and acid deposition (e.g., measurement of cloud liquid water content) have been ignored. In particular, we have not discussed particle size spectra measurements for various atmospheric condensed phases (aerosols, cloud droplets and precipitation). Further improvements in chemical measurement technologies can be anticipated especially in the areas of free radicals, oxidants, organics, and S02 and N02 at very low levels. Nevertheless, major incremental improvements in the understanding of acid deposition processes can be anticipated from the continuing airborne application of the techniques described in this review. 

Samet and J. D. Baltimore (eds.), Johns Hopkins University Press, 1991, p. 273. Byers, H. R., Elements of Cloud Physics, University of Chicago Press, Chicago, 1965a. Byers, H. R., Ind. Eng. Chem., 57,11 (1965b). 

Pinty J-P, Jabouille P (1998) A mixed-phase cloud parameterization for use in mesoscale non-hydrostatic model simulations of a squall line and of orographic precipitations. Proc. conf. of cloud physics, Everett, WA, USA, Amer. Meteor, soc., Aug. 1999, pp 217-220... 

I am just wondering about your statement that aerosols may have an effect on climate only during periods of strong volcanic activity by increasing the albedo. I am no expert in cloud physics, but I am wondering if increased aerosol burnings in the troposphere could affect cloud processes and thereby have an impact on climate. 

JOHN C. CARSTENS— Physics Department, Graduate Center for Cloud Physics Research, University of Missouri—Rolla, Rolla, MO 65401... 

Particles, Proc, Int, Conf, Cloud Physics, Toronto (1968 ) 24-29. 

Jouzel J. (1986) Isotopes in cloud physics multisteps and multistages processes. In Handbook of Environmental Isotopes Geochemistry Volume 2 The Terrestrial Environment B". (eds. P. Fritz and J. C. Fontes). Elsevier, vol. 2, pp. 61—112. 

Jouzel J. and Merlivat L. (1980) Growth regime of hailstones as deduced from simultaneous deuterium and oxygen 18 measurements. In Vllleme International Conference on Cloud Physics. Conference Proceedings AIMPA, Clermont-Ferrand, pp. 253—256. 

Rogers R. R. (1979) A Short Course in Clouds Physics (ed. Pergamon). 

Proceedings of the First Conference on the Physics of Cloud and Precipitation Particles Cloud Physics Conference Weickman, H. Smith, W., Eds. Pergamon London, 1957 pp. 47-72. 

Coen and Clark [128] has coupled a fire model into a three-dimensional non-hydrostatic terrain-following numerical mesoscale model developed at the US National Center for Atmospheric Research, Boulder, CO. The model includes rain and cloud physics. Calculations predict the growth and spread of a fire line moving across a two dimensional small Gaussian hill (height 200 m, half-width 300 m) for a wind speed of 3 m/s, and a stable atmospheric lapse rate (10°C/km). The head of the fire propagated quickly uphill in the direction of the environmental wind. Once the fire reaches the top of the hill, the updrafts tend to inhibit the forward movement of the fire front, and the fire spreads faster laterally in the lee of the hill. 

Byers, H. R. (1965) Elements of Cloud Physics, University of Chicago Press, Chicago. 

The problems related to the water cycle will also not be considered in spite of the fact that, taking into account its quantity and atmospheric effects, water is one of the most important trace materials. This omission is explained by a historical precedent. The study of the atmospheric cycle of the water as well as the measurement of its concentration were included in the past in the program of other branches of atmospheric science. Thus, the formation of clouds and precipitation, the subject of the cloud physics (e.g. Mason, 1957, Fletcher, 1962), will only be discussed in relation with the wet removal of aerosol particles and water-soluble gases. 

More precisely, climate modeling consists in the simulation of large-scale atmospheric processes by applying the basic physical principles and the correct initial conditions in a consistent way (Smagorinsky, 1974). An important part of climate modeling is the consideration of the interaction of macro-processes with phenomena taking place on the micro-scale (radiative transfer, turbulence, and processes of cloud physics and air chemistry). In the equations, the horizontal scale of variations is at least 100 km, while the vertical scale lies between 10 m and 100 km. The volume of air taken into account is a measure of the resolution of the calculation. Phenomena of smaller scale can be included in the model by appropriate statistical methods. This procedure is termed the parameterization. 

Fricke, W., Georgii, H. W. and Gravenhorst, G., 1978 Application of a new sampling device for cloud-water analysis. In Some problems of cloud physics. Gidrometeoizdat, Leningrad, 200-216. 

Modeling (chemical weather forecasting air quality and human health dispersion of chemicals aerosol and cloud physics)... 

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