Download or read book Derivation of Physical and Optical Properties of Mid latitude Cirrus Ice Crystals for a Size resolved Cloud Microphysics Model written by and published by . This book was released on 2016 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Springer Series in Light Scattering written by Alexander Kokhanovsky and published by Springer. This book was released on 2017-12-22 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a survey of modern theoretical and experimental techniques in studies of light scattering phenomena and radiative transfer processes in random media. It presents reviews on light scattering by sea water and bubbles, and includes a separate chapter addressing studies of the remote sensing of crystalline clouds with a focus on the shape of particles—a parameter rarely studied by passive remote sensing techniques. In particular, it offers a comprehensive analysis of polarized radiative transfer in optically active (e.g., chiral) light scattering media and explores advances in spectro-polarimetry of particulate media. Lastly it discusses new developments in light scattering for combustion monitoring.
Download or read book Clouds and Their Climatic Impact written by Sylvia Sullivan and published by John Wiley & Sons. This book was released on 2023-12-19 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clouds and Their Climatic Impacts Clouds are an influential and complex element of Earth’s climate system. They evolve rapidly in time and exist over small spatial scales, but also affect global radiative balance and large-scale circulations. With more powerful models and extensive observations now at our disposal, the climate impact of clouds is receiving ever more research attention. Clouds and Their Climatic Impacts: Radiation, Circulation, and Precipitation presents an overview of our current understanding on various types of clouds and cloud systems and their multifaceted role in the radiative budget, circulation patterns, and rainfall. Volume highlights include: Interactions of aerosol with both liquid and ice clouds Surface and atmospheric cloud radiative feedbacks and effects Arctic, extratropical, and tropical clouds Cloud-circulation coupling at global, meso, and micro scales Precipitation efficiency, phase, and measurements The role of machine learning in understanding clouds and climate The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.
Download or read book Mixed Phase Clouds written by Constantin Andronache and published by Elsevier. This book was released on 2017-09-28 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixed-Phase Clouds: Observations and Modeling presents advanced research topics on mixed-phase clouds. As the societal impacts of extreme weather and its forecasting grow, there is a continuous need to refine atmospheric observations, techniques and numerical models. Understanding the role of clouds in the atmosphere is increasingly vital for current applications, such as prediction and prevention of aircraft icing, weather modification, and the assessment of the effects of cloud phase partition in climate models. This book provides the essential information needed to address these problems with a focus on current observations, simulations and applications. Provides in-depth knowledge and simulation of mixed-phase clouds over many regions of Earth, explaining their role in weather and climate Features current research examples and case studies, including those on advanced research methods from authors with experience in both academia and the industry Discusses the latest advances in this subject area, providing the reader with access to best practices for remote sensing and numerical modeling
Download or read book Light Scattering by Ice Crystals written by Kuo-Nan Liou and published by Cambridge University Press. This book was released on 2016-10-06 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume outlines the fundamentals and applications of light scattering, absorption and polarization processes involving ice crystals.
Download or read book The Microphysics of Ice Clouds written by Rosemary M. Dyer and published by . This book was released on 1979 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published results of observations of crystal habits, particle sizes and numbers of ice particles in clouds are summarized and discussed. There are systematic variations with cloud type, and in some instances, with cloud age and location within a cloud system. However, the body of data available is insufficient to formulate a climatology of ice cloud microphysics. The several measurement techniques in current use are evaluated, as are some of the techniques now under consideration for future use. The particle enhancement observed on some occasions is discussed, and the various theories accounting for it presented. Finally, recommendations are made concerning future field programs and theoretical studies required before accurate predictions of the ice cloud microphysical environment can be made. (Author).
Download or read book Physical Processes in Clouds and Cloud Modeling written by Alexander P. Khain and published by Cambridge University Press. This book was released on 2018-07-05 with total page 643 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the most comprehensive and systematic description currently available of both classical and novel theories of cloud processes, providing a much-needed link between cloud theory, observation, experimental results, and cloud modeling. This volume shows why and how modern models serve as a major tool of investigation of cloud processes responsible for atmospheric phenomena, including climate change. It systematically describes classical as well as recent advancements in cloud physics, including cloud-aerosol interaction; collisions of particles in turbulent clouds; and the formation of multiphase cloud particles. As the first of its kind to serve as a practical guide for using state-of-the-art numerical cloud models, major emphasis is placed on explaining how microphysical processes are treated in modern numerical cloud resolving models. The book will be a valuable resource for advanced students, researchers and numerical model designers in cloud physics, atmospheric science, meteorology, and environmental science.
Download or read book Provisional Annotated Agenda for the 28th Session to be Held at the Palais Des Nations Geneva Starting on Tuesday 5 July 1994 and Concluding on Friday 8 July 1994 written by and published by . This book was released on 1994 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Climatic Implications of Ice Microphysics written by and published by . This book was released on 1995 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on aircraft measurements of mid-latitude cirrus clouds, ice crystal size distribution and ice water content (IWC) are shown to be dependent on temperature. This dependence is also evident from the theoretical consideration of ice crystal growth. Using simple models of the diffusion and accretion growth of ice particles, the computed mean ice crystal size and IWC compare reasonably well with the measured mean values. The temperature dependence of ice crystal size and IWC has important climatic implications in that the temperature field perturbed by external radiative forcings, such as greenhouse warming, can alter the composition of ice crystal clouds. Through radiative transfer, ice microphysics can in turn affect the temperature field. Higher IWC would increase cloud solar albedo and infrared emissivity, while for a given IWC, larger crystals would reduce cloud albedo and emissivity. The competing effects produced by greenhouse temperature perturbations via ice micro-physics and radiation interactions and feedbacks are assessed by a one-dimensional radiative-convective climate model that includes an advanced radiation parameterization program. 3 figs.
Download or read book Characterization of 3D Cirrus Cloud and Radiation Fields Using ARS AIRS MODIS Data and Its Application to Climate Model written by and published by . This book was released on 2016 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the report period, we have made the following research accomplishments. First, we performed analysis for a number of MODIS scenes comprising of heavy dust events and ice clouds, covering regions of frequent dust outbreaks in East Asia, Middle East, and West Africa, as well as areas associated with long-range dust transports over the Equatorial Tropical Atlantic Ocean. These scenes contain both dust/aerosols and clouds. We collected suitable aerosol/ice-cloud data, correlated ice cloud and aerosol parameters by means of statistical analysis, and interpreted resulting correlation trends based on the physical principles governing cloud microphysics. Aerosol and cloud optical depths and cloud effective particle size inferred from MODIS for selected domains were analyzed from which the parameters including dust aerosol number concentration, ice cloud water path, and ice particle number concentration were subsequently derived. We illustrated that the Twomey (solar albedo) effect can be statistically quantified based on the slope of best-fit straight lines in the correlation study. Analysis of aerosol and cloud retrieval products revealed that for all cases, the region with a larger dust aerosol optical depth is always characterized by a smaller cloud particle size, consistent with the Twomey hypothesis for aerosol-cloud interactions. Second, we developed mean correlation curves with uncertainties associated with small ice-crystal concentration observations for the mean effective ice crystal size (De) and ice water content (IWC) by dividing the atmosphere into three characteristic regions: Tropics cirrus, Midlatitude cirrus, including a temperature classification to improve correlation, and Arctic ice clouds. We illustrated that De has a high correlation with IWC based on theoretical consideration and analysis of thousands of observed ice crystal data obtained from a number of ARM-DOE field campaigns and other experiments. The correlation has the form: ln(De) = a + b ln(IWC) + c ((ln(IWC))2, where a, b, and c are fitting coefficients and are functions of three regions. We demonstrated that this correlation can be effectively incorporated in GCMs and climate models that predict IWC - a significant advance in ice microphysics parameterization for interactive cloud-radiation analysis and feedback. Substantial July mean differences are shown in the OLR (W/m2) and precipitation (mm/day) patterns between UCLA GCM simulations based on Des determined from the De-IWC correlations and the control run using a fixed ice crystal size. Third, in order to improve the computation of spectral radiative transfer processes in the WRF model, we developed a consistent and efficient radiation scheme that can better resolve the spectral bands, determine the cloud optical properties, and provide more reliable and accurate radiative heating fields. In the newly developed radiation module, we have implemented in WRF a modified and improved version referred to as the Fu-Liou-Gu scheme, which includes a combination of delta-four-stream and delta-two-stream approximations for solar and IR flux calculations, respectively. This combination has been proven to be computationally efficient and at the same time to produce a high degree of accuracy. The incorporation of nongray gaseous absorption in multiple scattering atmospheres was based on the correlated k-distribution method. The solar and IR spectra are divided into 6 and 12 bands, respectively, according to the location of absorption bands of H2O, CO2, O3, CH4, N2O, and CFCs. We further included absorption by the water vapor continuum and a number of minor absorbers in the solar spectrum leading to an additional absorption of solar flux in a clear atmosphere on the order of 1-3 W/m2. Additionally, we incorporated the ice microphysics parameterization that includes an interactive mean effective ice crystal size in association with radiation parameterizations. The Fu-Liou-Gu scheme is an ideal tool for t ...
Download or read book Simulation of the Extinction Efficiency the Absorption Efficiency and the Asymmetry Factor of Ice Crystals and Relevant Applications to the Study of Cirrus Cloud Radiative Properties written by Kai Lu and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The single-scattering properties of six non-spherical ice crystals, droxtals, plates, solid columns, hollow columns, aggregates and 6-branch bullet rosettes are simulated. The anomalous diffraction theory (ADT) is applied to the simulation of the extinction efficiency and the absorption efficiency. Because the first order reflection is considered, the accuracy of the absorption efficiency increases with the increasing of the size parameter. Compared with the reference single-scattering properties from an improved geometric optics method (IGOM), the errors in the extinction and absorption efficiencies are small. In addition, the asymmetry factor is formulated within the framework of diffraction and external reflection. The asymmetry factor based on the ADT matches very well with the IGOM counterpart when the absorption is strong, but needs an improvement in the solar region. The errors in conjunction with the application of the ADT-based optical properties to the computation of atmospheric fluxes and heating rates, based on the Fu-Liou model also are investigated. Two cases, one for tropical cirrus clouds and the other for mid-latitude cirrus clouds, are designed. It is found that the errors of bulk asymmetry factor between ADT-based and IGOM-based result in an overestimation of downward infrared (IR) fluxes and upward solar fluxes, and an underestimation of upward IR fluxes and downward solar fluxes. The errors of the fluxes and heating rates based on two sets of single-scattering properties are caused mainly by the underestimation of the bulk absorption efficiency based on ADT. It is also shown that ADT-based optical properties generate more accurate radiative properties for tropical cirrus clouds than for the mid-latitude cirrus clouds. In conclusion, the ADT-based method can generate reasonably accurate single-scattering properties of ice crystals, and can result in reasonable upward IR and solar fluxes at top of atmosphere (TOA), downward IR fluxes at the surface, and net heating rates.
Download or read book The Effects of Ice Crystal Shape on the Evolution of Optically Thin Cirrus Clouds in the Tropics written by Rick Russotto and published by . This book was released on 2015 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin cirrus clouds in the tropical tropopause layer (TTL) play potentially important roles in Earth's radiation budget and in the transport of water into the stratosphere. Radiative heating of these clouds results in mesoscale circulations that maintain them against sedimentation and redistribute water vapor. In this study, the System for Atmospheric Modeling (SAM) cloud-resolving model is modified in order to calculate the fall speeds, growth rates, and radiative absorption coefficients of non-spherical ice crystals. This extended model is used in simulations that aim to constrain the effects of ice crystal shape on the time evolution of thin cirrus clouds and to identify the physical processes responsible. Model runs assuming spheroidal crystals result in a higher center of cloud ice mass than in the control, spherical case, which is roughly 60% due to a reduction in fall speeds and 40% due to stronger updrafts caused by stronger radiative heating. Other effects of ice crystal shape on the cloud evolution include faster growth and sublimation in supersaturated and subsaturated environments, respectively, and local temperature increases caused by diabatic heating. Effects of ice crystal shape on the total and mean ice crystal masses are within about 10% but do not appear to be entirely negligible. Comparisons of modeled ice crystal size distributions with recent airborne observations of TTL cirrus show that incorporating non-spherical shape has the potential to bring the model closer to observations. It is hoped that this work will eventually lead towards a more realistic physical representation of thin tropical cirrus in global climate models.
Download or read book Study of Ice Cloud Properties Using Infrared Spectral Data written by Kevin James Garrett and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The research presented in this thesis involves the study of ice cloud microphysical and optical properties using both hyperspectral and narrowband infrared spectral data. First, ice cloud models are developed for the Infrared Atmospheric Sounding Interferometer (IASI) instrument onboard the METOP-A satellite, which provide the bulk-scattering properties of these clouds for the 8461 IASI channels between 645 and 2760 cm-1. We investigate the sensitivity of simulated brightness temperatures in this spectral region to the bulk-scattering properties of ice clouds containing individual ice crystal habits as well as for one habit distribution. The second part of this thesis describes an algorithm developed to analyze the sensitivity of simulated brightness temperatures at 8.5 and 11.0 ℗æm to changes in effective cloud temperature by adjusting cloud top height and geometric thickness in a standard tropical atmosphere. Applicability of using these channels in a bi-spectral approach to retrieve cirrus cloud effective particle size and optical thickness is assessed. Finally, the algorithm is applied to the retrieval of these ice cloud properties for a case of single-layered cirrus cloud over a tropical ocean surface using measurements from the Moderate Resolution Infrared Spectroradiometer (MODIS). Cloud top height and geometric thickness in the profile are adjusted to assess the influence of effective cloud temperature on the retrieval.
Download or read book An Introduction to Atmospheric Radiation written by K. N. Liou and published by Academic Press. This book was released on 2002-04-29 with total page 599 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of radiation for atmospheric applications -- Solar radiation at the top of the atmosphere -- Absorption and scattering of solar radiation in the atmosphere -- Thermal infrared radiation transfer in the atmosphere -- Light scattering by atmospheric particulates -- Principles of radiative transfer in planetary atmospheres -- Application of radiative transfer principles to remote sensing -- Radiation and climate.
Download or read book Journal of Atmospheric and Oceanic Technology written by and published by . This book was released on 2001 with total page 1032 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Unique Ice Crystal Observations from the ICE Ball Field Campaign Combined with Model Simulations Elucidate Cirrus Development written by Marley Majetic and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cirrus clouds are ubiquitous over large spatial domains on Earth, yet the detailed morphology of the small ice crystals that compose these clouds is not well understood. Ice crystal surface structure influences crystal growth rates and radiative properties that can have either a positive or negative contribution to climatic warming. This work provides new observations of small cirrus particles collected during the Ice Cryo Encapsulation by Balloon (ICE-Ball) campaign that took place in Oklahoma for three weeks during the fall of 2021. Scanning Electron Microscope (SEM) images of crystals exhibit the frequent occurrence of complex polycrystalline habits, such as scroll rosettes, and frequent hollowing of small ice crystals, suggesting that faceting instability occurs on crystals with dimensions as small as 20 [mu]m. These results indicate that the effective density of small crystals may be less than prior in-situ estimates. Backward and forward trajectory calculations using the Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT) are used together with meteorological characterization based on ERA5 reanalysis to analyze the background airmass characteristics in which the observed cirrus formed. These analyses provide forcing for one-dimensional model simulations of a cirrus case that occurred on October 23rd, 2021; scroll rosettes were the dominant habit sampled. Laboratory measurements of rosette growth are used to inform model microphysics, thereby facilitating a more accurate depiction of the vapor depositional growth of cirrus crystals. These model simulations, in conjunction with the ICE-Ball in-situ samples, vertically pointing radar and lidar measurements, satellite observations, and reanalysis data, are used to estimate the spatiotemporal extent and lifetime of the cirrus cloud field observed on October 23rd, 2021, contributing to the understanding of ice crystal morphological development and the associated environmental feedbacks.
