Of prime interest are the radiation data from that portion of the infrared spectrum known as the atmospheric water-vapor window, ranging from about 8 to 12 microns. Infrared signals received by weather satellites and aircraft depend, in clear air, on surface temperature, atmospheric interference and surface emissivity. For the latter, very different data in literature are found for clouds, water, rocks, etc. In this report correct emissivity data were sought in three ways: (1) Reflectivity of polished rock samples was tested in an infrared spectrograph for 5-16 microns wavelength. Using Kirchhoff's law this method yielded emissivities for near normal incidence. (2) Using an 8-13 microns sensitive radiometer and an aggregate, called emissivity box, the emissivity of many surfaces was measured directly. (3) A summer noon time flight of Tiros over the Mediterranean and the Sahara was evaluated.

This book presents current applications of remote sensing techniques for clouds and precipitation for the benefit of students, educators, and scientists. It covers ground-based systems such as weather radars and spaceborne instruments on satellites. Measurements and modeling of precipitation are at the core of weather forecasting, and long-term observations of the cloud system are vital to improving atmospheric models and climate projections. The first section of the book focuses on the use of ground-based weather radars to observe and measure precipitation and to detect and forecast storms, thunderstorms, and tornadoes. It also discusses the observation of clouds using ground-based millimeter radar. The second part of the book concentrates on spaceborne remote sensing of clouds and precipitation. It includes cases from the Tropical Rainfall Measuring Mission (TRMM) and the Global Precipitation Measurement (GPM) mission, using satellite radars to observe precipitation systems. Then, the focus is on global cloud observations from the ClaudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), including a perspective on the Earth Clouds, Aerosols, and Radiation Explorer (EarthCARE) satellite. It also addresses global atmospheric water vapor profiling for clear and cloudy conditions using microwave observations. The final part of this volume provides a perspective into advances in cloud modeling using remote sensing observations.