Numerical weather predictionNumerical weather prediction (NWP) uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. Though first attempted in the 1920s, it was not until the advent of computer simulation in the 1950s that numerical weather predictions produced realistic results. A number of global and regional forecast models are run in different countries worldwide, using current weather observations relayed from radiosondes, weather satellites and other observing systems as inputs.
Cloud seedingCloud seeding is a type of weather modification that aims to change the amount or type of precipitation that falls from clouds by dispersing substances into the air that serve as cloud condensation or ice nuclei, which alter the microphysical processes within the cloud. Its effectiveness is debated; some studies have suggested that it is "difficult to show clearly that cloud seeding has a very large effect." The usual objective is to increase precipitation (rain or snow), either for its own sake or to prevent precipitation from occurring in days afterward.
Smoke screenA smoke screen is smoke released to mask the movement or location of military units such as infantry, tanks, aircraft, or ships. Smoke screens are commonly deployed either by a canister (such as a grenade) or generated by a vehicle (such as a tank or a warship). Whereas smoke screens were originally used to hide movement from enemies' line of sight, modern technology means that they are now also available in new forms; they can screen in the infrared as well as visible spectrum of light to prevent detection by infrared sensors or viewers, and they are also available for vehicles in a super-dense form used to block laser beams of enemy laser designators or rangefinders.
Geometric albedoIn astronomy, the geometric albedo of a celestial body is the ratio of its actual brightness as seen from the light source (i.e. at zero phase angle) to that of an idealized flat, fully reflecting, diffusively scattering (Lambertian) disk with the same cross-section. (This phase angle refers to the direction of the light paths and is not a phase angle in its normal meaning in optics or electronics.) Diffuse scattering implies that radiation is reflected isotropically with no memory of the location of the incident light source.
Martian surfaceThe study of surface characteristics (or surface properties and processes) is a broad category of Mars science that examines the nature of the materials making up the Martian surface. The study evolved from telescopic and remote-sensing techniques developed by astronomers to study planetary surfaces. However, it has increasingly become a subdiscipline of geology as automated spacecraft bring ever-improving resolution and instrument capabilities.
Station modelIn meteorology, station models are symbolic illustrations showing the weather occurring at a given reporting station. Meteorologists created the station model to fit a number of weather elements into a small space on weather maps. This allows map users to analyze patterns in atmospheric pressure, temperature, wind speed and direction, cloud cover, precipitation, and other parameters. The most common station plots depict surface weather observations although upper air plots at various mandatory levels are also frequently depicted.
NeptuneNeptune is the eighth planet from the Sun and the farthest IAU-recognized planet in the Solar System. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth, and slightly more massive than its near-twin Uranus. Neptune is denser and physically smaller than Uranus because its greater mass causes more gravitational compression of its atmosphere. Being composed primarily of gases and liquids, it has no well-defined solid surface.
