Physics and chemistry of clouds Clouds affect our daily weather and play key roles in the global climate. Through their ability to precipitate clouds provide virtually all of the fresh water on Earth and are a crucial link in the hydrologic cycle. With ever increasing importance being placed on quantifiable predictions from forecasting the local weather to anticipating climate change we must understand how clouds operate in the real atmosphere where interactions with natural and anthropogenic pollutants are common. This textbook provides students whether seasoned or new to the atmospheric sciences with a quantitative yet approachable path to learning the inner workings of clouds. Developed over many years of the authors teaching at Pennsylvania State University Physics and Chemistry of Clouds is an invaluable textbook for advanced students in atmospheric science meteorology environmental sciences engineering and atmospheric chemistry. It is also a very useful reference text for researchers and professionals Clouds contribute to the environment in many ways. Clouds through a variety of physical processes acting over many spatial scales provide both liquid and solid forms of precipitation and natures only significant source of fresh water. Under extreme circumstances however clouds and precipitation may not form at all leading to prolonged droughts in some regions. At other times and places too much rain or snow falls giving rise to devastating floods or blizzards. Liquid rain drops bring usable water directly to the surface while simultaneously carrying many trace chemicals out of the atmosphere and into the ecosystems of the Earth. Chemical wet deposition thereby supplies nutrients (and sometimes toxic compounds) to both terrestrial and aquatic lifeforms as well as the weak acids responsible for the weathering of the Earths crust. The solid forms of precipitation contribute in additional ways to the world as we know it. Snow for instance forms the winter snowpacks that dramatically affect the radiation balance and climate of high latitudes on a seasonal basis