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Cloud Base
A cloud base (or the base of the cloud) is the lowest altitude of the visible portion of a cloud. It is traditionally expressed either in metres or feet above mean sea level or above a planetary surface, or as the pressure level corresponding to this altitude in hectopascals (hPa, equivalent to the millibar). Measurement The height of the cloud base can be measured using a ceilometer. This device reflects a beam of light off the cloud base and then calculates its distance using either triangulation or travel time. Alternatively, the cloud base can be estimated from surface measurements of air temperature and humidity by calculating the lifted condensation level. One method for doing this, used by the U.S. Federal Aviation Administration and often named after Tom Bradbury, is as follows: #Find the difference between the surface temperature and the dew point. This value is known as the "spread". #Divide the spread by 4.4 (if temperatures are in °F) or 2.5 (if temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Captain Scarlet And The Mysterons
''Captain Scarlet and the Mysterons'', often shortened to ''Captain Scarlet'', is a British science fiction television series created by Gerry Anderson, Gerry and Sylvia Anderson and filmed by their production company AP Films#Century 21, Century 21 for ITC Entertainment. It is the sixth Anderson series to be filmed using a form of electronic marionette puppetry dubbed "Supermarionation" combined with scale model special effects. Running to thirty-two 25-minute episodes, it was first broadcast on ITV (TV network), ITV regional franchises between 1967 and 1968 and has since aired in more than 40 other countries, including the United States, Canada, Australia, New Zealand and Japan. Set in 2068, ''Captain Scarlet'' presents a "Wikt:war of nerves, war of nerves" between Earth and the Mysterons, a race of Martians who possess partial control over matter. When a misunderstanding causes human astronauts to attack their city on Mars, the Mysterons swear revenge and launch reprisals aga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clouds
In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles, suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may compose the droplets and crystals. On Earth, clouds are formed as a result of saturation of the air when it is cooled to its dew point, or when it gains sufficient moisture (usually in the form of water vapor) from an adjacent source to raise the dew point to the ambient temperature. Clouds are seen in the Earth's homosphere, which includes the troposphere, stratosphere, and mesosphere. Nephology is the science of clouds, which is undertaken in the cloud physics branch of meteorology. The World Meteorological Organization uses two methods of naming clouds in their respective layers of the homosphere, Latin and common name. Genus types in the troposphere, the atmospheric layer closest to Earth's surface, have Latin names because of the u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloud Height
In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles, suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may compose the droplets and crystals. On Earth, clouds are formed as a result of saturation of the air when it is cooled to its dew point, or when it gains sufficient moisture (usually in the form of water vapor) from an adjacent source to raise the dew point to the ambient temperature. Clouds are seen in the Earth's homosphere, which includes the troposphere, stratosphere, and mesosphere. Nephology is the science of clouds, which is undertaken in the cloud physics branch of meteorology. The World Meteorological Organization uses two methods of naming clouds in their respective layers of the homosphere, Latin and common name. Genus types in the troposphere, the atmospheric layer closest to Earth's surface, have Latin names because of the univ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloud Cover
Cloud cover (also known as cloudiness, cloudage, or cloud amount) refers to the fraction of the sky obscured by clouds on average when observed from a particular location. Okta is the usual unit for measurement of the cloud cover. The cloud cover is correlated to the sunshine duration as the least cloudy locales are the sunniest ones while the cloudiest areas are the least sunny places, as clouds can block sunlight, especially at sunrise and sunset where sunlight is already limited. The global cloud cover averages around 67-68%, though it ranges from 56% to 73% depending on the minimum optical depth considered (lower when optical depth is large, and higher when it is low, such that subvisible cirrus clouds are counted). Average cloud cover is around 72% over the oceans, with low seasonal variation, and about 55% above land, with significant seasonal variation. Role in the climate system Clouds play multiple critical roles in the climate system and diurnal cycle. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceiling (cloud)
In aviation, ceiling is a measurement of the height of the base of the lowest clouds (not to be confused with cloud base which has a specific definition) that cover more than half of the sky (more than 4 oktas) relative to the ground. Ceiling is not specifically reported as part of the METAR (METeorological Aviation Report) used for flight planning by pilots worldwide, but can be deduced from the lowest height with broken (BKN) or overcast (OVC) reported. A ceiling listed as "unlimited" means either that the sky is mostly free of cloud cover, or that the clouds are high enough not to impede visual flight rules (VFR) operation. Definitions ; ICAO The International Civil Aviation Organization (ICAO ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international sch ... : The height above the ground or water of the base of the lowest layer of cloud be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instrument Flight Rules
In aviation, instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR). The U.S. Federal Aviation Administration's (FAA) ''Instrument Flying Handbook'' defines IFR as: "Rules and regulations established by the FAA to govern flight under conditions in which flight by outside visual reference is not safe. IFR flight depends upon flying by reference to instruments in the flight deck, and navigation is accomplished by reference to electronic signals." It is also a term used by pilots and controllers to indicate the type of flight plan an aircraft is flying, such as an IFR or VFR flight plan. Basic information Comparison to visual flight rules It is possible and fairly straightforward, in relatively clear weather conditions, to fly an aircraft solely by reference to outside visual cues, such as the horizon to maintain orientation, nearby buildings and terrain features for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Flight Rules
In aviation, visual flight rules (VFR) is a set of regulations under which a pilot operates an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Specifically, the weather must be better than basic VFR weather minima, i.e., in visual meteorological conditions (VMC), as specified in the rules of the relevant aviation authority. The pilot must be able to operate the aircraft with visual reference to the ground, and by visually avoiding obstructions and other aircraft. If the weather is less than VMC, pilots are required to use instrument flight rules, and operation of the aircraft will be primarily through referencing the instruments rather than visual reference. In a control zone, a VFR flight may obtain a clearance from air traffic control to operate as Special VFR. Requirements VFR requires a pilot to be able to see outside the cockpit to control the aircraft's altitude, navigate, and avoid obstacles and other aircra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kirchhoff's Law Of Thermal Radiation
In heat transfer, Kirchhoff's law of thermal radiation refers to wavelength-specific radiative emission and absorption by a material body in thermodynamic equilibrium, including radiative exchange equilibrium. It is a special case of Onsager reciprocal relations as a consequence of the time reversibility of microscopic dynamics, also known as microscopic reversibility. A body at temperature radiates electromagnetic energy. A perfect black body in thermodynamic equilibrium absorbs all light that strikes it, and radiates energy according to a unique law of radiative emissive power for temperature (Stefan–Boltzmann law), universal for all perfect black bodies. Kirchhoff's law states that: Here, the dimensionless coefficient of absorption (or the absorptivity) is the fraction of incident light (power) at each spectral frequency that is absorbed by the body when it is radiating and absorbing in thermodynamic equilibrium. In slightly different terms, the emissive power ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiation
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes: * ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and Gamma ray, gamma radiation (γ) * ''particle radiation'' consisting of particles of non-zero rest energy, such as alpha radiation (α), beta radiation (β), proton radiation and neutron radiation * ''acoustics, acoustic radiation'', such as ultrasound, sound, and seismic waves, all dependent on a physical transmission medium * ''gravitational radiation'', in the form of gravitational waves, ripples in spacetime Radiation is often categorized as either ''ionizing radiation, ionizing'' or ''non-ionizing radiation, non-ionizing'' depending on the energy of the radiated particles. Ionizing radiation carries more than 10 electron volt, electron volts (eV), which is enough to ionize atoms and molecul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Convection
Atmospheric convection is the vertical transport of heat and moisture in the atmosphere. It occurs when warmer, less dense air rises, while cooler, denser air sinks. This process is driven by parcel-environment instability, meaning that a "parcel" of air is warmer and less dense than the surrounding environment at the same altitude. This difference in temperature and density (and sometimes humidity) causes the parcel to rise, a process known as buoyancy. This rising air, along with the compensating sinking air, leads to mixing, which in turn expands the height of the planetary boundary layer (PBL), the lowest part of the atmosphere directly influenced by the Earth's surface. This expansion contributes to increased winds, cumulus cloud development, and decreased surface dew points (the temperature below which condensation occurs). Convection plays a crucial role in weather patterns, influencing cloud formation, wind, and the development of thunderstorms, which can be associa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloud Top
The cloud top (or the top of the cloud) is the highest altitude of the visible portion of a cloud. It is traditionally expressed either in metres above the Earth (or planetary) surface, or as the corresponding pressure level in hectopascal (hPa, equivalent to the traditional but now obsolete millibar). Measurement The cloud top is where the snow, rain and sleet come from. Cloud top height can be estimated from the ground by triangulation. However, this is often inconvenient as this is practically feasible only for isolated clouds in full view of (and some horizontal distance away from) the observers. Ground-based radars can be used to derive this cloud property. An alternative (but also more expensive) approach is to acquire airborne observations either visually or using specific instruments such as a lidar. This technique is very appropriate to characterize individual clouds (and specifically to control or evaluate the accuracy of other methods) but becomes unmanageable to repetit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
