Fourth National Aeronautics and Space Administration Weather and Climate Program Science Review

The NASA Weather and Climate Program has two major thrusts. The first involves the development of experimental and prototype operational satellite systems, sensors, and space facilities for monitoring and understanding the atmosphere. The second thrust involves basic scientific investigation aimed at studying the physical and chemical processes which control weather and climate. This fourth science review concentrated on the scientific research rather than the hardware development aspect of the program. These proceedings contain 65 papers covering the three general areas: severe storms and local weather research, global weather, and climate

Fatigue crack detection on structural steel members by using ultrasound excited thermography = Erkennung von Ermüdungsrissen in Stahlbauteilen durch ultraschallangeregte Thermografie

Ultrasound excitation of structural steel members leads to localised energy dissipation at existent fatigue cracks and thus allows for thermographic flaw detection. Essential effects on the defect-selective heating such as flaw size, plate thickness, crack mouth opening or static preload are systematically investigated. Laser vibrometry measurements of the crack edges, theoretical modelling of frictional heating and numerical simulations contribute to the understanding of the involved physics

Studies in geophysics: The Earth's electrical environment

The Earth is electrified. Between the surface and the outer reaches of the atmosphere, there is a global circuit that is maintained by worldwide thunderstorm activity and by upper atmospheric dynamo processes. The highest voltages approach a billion volts and are generated within thunderclouds, where lightning is a visual display of the cloud's electrical nature. The largest currents in the circuit, approaching a million amperes, are associated with the aurora. Because there have been significant advances in understanding many of the component parts of the global electric circuit (lightning, cloud electrification, electrical processes in specific atmospheric regions, and telluric currents), a principal research challenge is to understand how these components interact to shape the global circuit. Increased basic understanding in this field has many potential practical applications, including lightning protection, the design of advanced aircraft and spacecraft, and improvements in weather prediction

Annual Report of the Board of Regents of the Smithsonian Institution, showing the operations, expenditures, and condition of the Institution for the year ending June 30, 1887

Annual Report of the Smithsonian Institution. [2581-2582] Research related to the American Indian