Clouds Their Formation Optical Properties And Effects

Clouds: Their Formation, Optical Properties, and Effects deals with the formation of clouds as well as the theoretical and experimental aspects of their microphysical and optical properties. Discussions are grouped under the headings of structure of clouds, interaction of passive radiation with clouds, and interaction of active radiation with clouds. This book is organized into three sections and has 11 chapters. After analyzing the spatial and temporal scales involved in the formation and organization of clouds and precipitation, this text examines the microphysical measurement techniques used in probing the microstructure of clouds. The reader is then methodically introduced to the microstructure of atmospheric clouds and precipitation; the formation and structure of fog; and basic shortwave characteristics of “ideal clouds. The temporal behavior of clouds and their interaction with the radiation field are considered, along with the possible effects of cloud models in general circulation studies. The remaining chapters explore the light scattering properties of ice crystals and the radiative characteristics of ice clouds; the laser measurements in clouds; the transmission and reflectivity of ice clouds by active probing; and the theory of multiple scattering of laser beams in clouds. The book concludes by presenting the measurements of the temporal and spatial spreading of a blue-green pulse through clouds and fogs as a function of optical thickness and receiver field-of-view. This text will be helpful to advanced researchers and program managers in terms of reviewing the state of the art and identifying those areas requiring further research efforts.

Aerosols play a critical role in a broad range of scientific disciplines, such as atmospheric chemistry and physics, combustion science, drug delivery and human health. This thesis explores the fundamentals of a new technique for capturing single or multiple particles using light, and for characterising these particles by Raman or fluorescence spectroscopy. The outcome of this research represents a significant development in optical manipulation techniques, specifically in optical tweezing. These findings can be applied to studies of the mass accommodation of gas-phase water molecules adsorbing onto a water surface. Not only is this a fundamental process of interest to physical chemists, but it is important for understanding the role of aerosol particles in the atmosphere, including their ability to become cloud droplets. This new strategy for investigating aerosol dynamics is fundamental in helping us understand the indirect effect of aerosols on the climate.

Fundamentals of Atmospheric Physics emphasizes the interrelationships of physical and dynamical meteorology. The text unifies four major subject areas: atmospheric thermodynamics, hydrostatic equilibrium and stability, atmospheric radiation and clouds, and atmospheric dynamics. These fundamental areas serve as cornerstones of modern atmospheric research on environmental issues like global change and ozone depletion. Physical concepts underlying these subject areas are developed from first principles, providing a self-contained text for students and scholars from diverse backgrounds. The presentation is Lagrangian (single-body problems) in perspective, with a balance of theory and application. Each chapter includes detailed and extensive problems; selected answers are provided, as are appendices of various constants. The text requires a thorough foundation in calculus. Presents a comprehensive introduction to atmospheric thermodynamics, hydrostatics, radiation and clouds, and dynamics Develops concepts from first principles, providing a self-contained volume for readers from diverse backgrounds Emphasizes the interaction of physical processes shaping global problems of atmospheric energetics, transport, and chemistry Provides a balance of theory and applications, with examples drawn from a wide range of phenomena figuring in global atmospheric research Extensively illustrated with global satellite imagery and analyses and photographs of laboratory simulations Exercises apply to a wide range of topical problems

In this thesis, a new lidar (light detection and ranging) ceilometer capable of monitoring cloud base and sensitive to boundary layer aerosols is introduced. The key to this novelty lies in its divided-lens design that addresses a classical lidar problem of balancing transmitter-receiver overlap and signal-to-noise ratio, along with a method for characterizing overlap in the laboratory. Enhanced sensitivity in the near-range of the instrument is achieved without compromising signal-to-noise in a design that is straightforward to manufacture for broad deployment. The instrument, its optical characterization, and its performance in the field are described. The prototype instrument described here has since formed the basis of a commercial sensor for monitoring clouds and aerosols. High-resolution, continuous observations of clouds and aerosols are needed to reduce the large uncertainties in our current understanding of their influence on climate that have been highlighted by the International Panel on Climate Change. And as international health organizations indicate growing public health threats over the coming decades resulting from poor air quality, extensive aerosol monitoring is required to assess personal exposure to and the health impacts of anthropogenic particulates. Ground-based optical remote sensing measurements made by well-characterized instruments, such as that described in these pages, are critical to this.

Life on Earth is critically dependent upon the continuous cycling of water between oceans, continents and the atmosphere. Precipitation (including rain, snow, and hail) is the primary mechanism for transporting water from the atmosphere back to the Earth’s surface. It is also the key physical process that links aspects of climate, weather, and the global hydrological cycle. Changes in precipitation regimes and the frequency of extreme weather events, such as floods, droughts, severe ice/snow storms, monsoon fluctuations and hurricanes are of great potential importance to life on the planet. One of the factors that could contribute to precipitation modification is aerosol pollution from various sources such as urban air pollution and biomass burning. Natural and anthropogenic changes in atmospheric aerosols might have important implications for precipitation by influencing the hydrological cycle, which in turn could feed back to climate changes. From an Earth Science perspective, a key question is how changes expected in climate will translate into changes in the hydrological cycle, and what trends may be expected in the future. We require a much better understanding and hence predictive capability of the moisture and energy storages and exchanges among the Earth’s atmosphere, oceans, continents and biological systems. This book is a review of our knowledge of the relationship between aerosols and precipitation reaching the Earth's surface and it includes a list of recommendations that could help to advance our knowledge in this area.

This text, devoted entirely to cirrus clouds, captures the state of knowledge of cirrus clouds and serves as a practical handbook as well.