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Millimetre Cloud Radar
Millimeter-wave cloud radars, also denominated cloud radars, are radar systems designed to monitor clouds with operating frequencies between 24 and 110 GHz (Table 1). Accordingly, their wavelengths range from 1 mm to 1.11 cm, about ten times shorter than those used in conventional S band radars such as NEXRAD. Purpose Table 1: Millimetre cloud radar operating bands The main purpose of these radars is the investigation of cloud properties and evolution. They typically operate at 35 GHz in the Ka band and at 94 GHz in the W band, where the atmospheric transmission is maximum. These frequencies correspond to wavelengths around 8 and 3 mm. Millimeter cloud radars have a high temporal and range resolution: temporal resolution is adjustable and typically ranges from 1 to 10 seconds, while thrange resolutionranges from a few meters for cloud radars using frequency modulation of the transmitted signal (e.g. 4 m for the Frequency-Modulated Continuous-Wav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Millimeter-wave Cloud Radar
Extremely high frequency (EHF) is the International Telecommunication Union (ITU) designation for the band of radio frequencies in the electromagnetic spectrum from 30 to 300 gigahertz (GHz). It lies between the super high frequency band and the far infrared band, the lower part of which is the terahertz band. Radio waves in this band have wavelengths from ten to one millimetre, so it is also called the millimetre band and radiation in this band is called millimetre waves, sometimes abbreviated MMW or mmWave. Millimetre-length electromagnetic waves were first investigated by Indian physicist Jagadish Chandra Bose, who generated waves of frequency up to 60GHz during experiments in 18941896. Compared to lower bands, radio waves in this band have high atmospheric attenuation: they are absorbed by the gases in the atmosphere. Absorption increases with frequency until at the top end of the band the waves are attenuated to zero within a few meters. Absorption by humidity in the atmosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lidar
Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be used to make digital 3-D representations of areas on the Earth's surface and ocean bottom of the intertidal and near coastal zone by varying the wavelength of light. It has terrestrial, airborne, and mobile applications. ''Lidar'' is an acronym of "light detection and ranging" or "laser imaging, detection, and ranging". It is sometimes called 3-D laser scanning, a special combination of 3-D scanning and laser scanning. Lidar is commonly used to make high-resolution maps, with applications in surveying, geodesy, geomatics, archaeology, geography, geology, geomorphology, seismology, forestry, atmospheric physics, laser guidance, airborne laser swath mapping (ALSM), and laser altimetry. It is also used in control and navigation for som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Radiation Measurement
The Atmospheric Radiation Measurement Climate Research Facility (ARM Climate Research Facility) is a multi-laboratory United States Department of Energy scientific user facility used for national and international global climate research efforts. The ARM Climate Research Facility consists of three heavily instrumented fixed-location atmospheric observatories and mobile and aerial research facilities that measure radiative properties of the atmosphere, particularly cloud and aerosol formation processes. Continuous data from these sites, as well as supplemental data obtained through intensive field research campaigns, are available to scientists online through the ARM Data Archive. ARM is collaboratively managed by nine DOE national laboratories. Mission ARM seeks to provide the climate research community with strategically located in situ and remote-sensing observatories designed to improve the understanding and representation, in climate and earth system models, of clouds and aer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polarimetry
Polarimetry is the measurement and interpretation of the polarization of transverse waves, most notably electromagnetic waves, such as radio or light waves. Typically polarimetry is done on electromagnetic waves that have traveled through or have been reflected, refracted or diffracted by some material in order to characterize that object. Plane polarized light: According to the wave theory of light, an ordinary ray of light is considered to be vibrating in all planes of right angles to the direction of its propagation. If this ordinary ray of light is passed through a nicol prism, the emergent ray has its vibration only in one plane. Applications Polarimetry of thin films and surfaces is commonly known as ellipsometry. Polarimetry is used in remote sensing applications, such as planetary science, astronomy, and weather radar. Polarimetry can also be included in computational analysis of waves. For example, radars often consider wave polarization in post-processing to imp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kurtosis
In probability theory and statistics, kurtosis (from el, κυρτός, ''kyrtos'' or ''kurtos'', meaning "curved, arching") is a measure of the "tailedness" of the probability distribution of a real-valued random variable. Like skewness, kurtosis describes a particular aspect of a probability distribution. There are different ways to quantify kurtosis for a theoretical distribution, and there are corresponding ways of estimating it using a sample from a population. Different measures of kurtosis may have different interpretations. The standard measure of a distribution's kurtosis, originating with Karl Pearson, is a scaled version of the fourth moment of the distribution. This number is related to the tails of the distribution, not its peak; hence, the sometimes-seen characterization of kurtosis as "peakedness" is incorrect. For this measure, higher kurtosis corresponds to greater extremity of deviations (or outliers), and not the configuration of data near the mean. It is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skewness
In probability theory and statistics, skewness is a measure of the asymmetry of the probability distribution of a real-valued random variable about its mean. The skewness value can be positive, zero, negative, or undefined. For a unimodal distribution, negative skew commonly indicates that the ''tail'' is on the left side of the distribution, and positive skew indicates that the tail is on the right. In cases where one tail is long but the other tail is fat, skewness does not obey a simple rule. For example, a zero value means that the tails on both sides of the mean balance out overall; this is the case for a symmetric distribution, but can also be true for an asymmetric distribution where one tail is long and thin, and the other is short but fat. Introduction Consider the two distributions in the figure just below. Within each graph, the values on the right side of the distribution taper differently from the values on the left side. These tapering sides are called ''tail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salzburg, Austria
Salzburg (, ; literally "Salt-Castle"; bar, Soizbuag, label=Bavarian language, Austro-Bavarian) is the List of cities and towns in Austria, fourth-largest city in Austria. In 2020, it had a population of 156,872. The town is on the site of the Roman settlement of ''Iuvavum''. Salzburg was founded as an episcopal see in 696 and became a Prince-Archbishopric of Salzburg, seat of the archbishop in 798. Its main sources of income were salt extraction, trade, and gold mining. The fortress of Hohensalzburg Fortress, Hohensalzburg, one of the largest medieval fortresses in Europe, dates from the 11th century. In the 17th century, Salzburg became a center of the Counter-Reformation, with monasteries and numerous Baroque churches built. Historic Centre of the City of Salzburg, Salzburg's historic center (German language, German: ''Altstadt'') is renowned for its Baroque architecture and is one of the best-preserved city centers north of the Alps. The historic center was enlisted as a UN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Altitude And Long Range Research Aircraft
The Gulfstream G550 is a business jet aircraft produced by General Dynamics' Gulfstream Aerospace unit in Savannah, Georgia, US. The certification designation is GV-SP. A version with reduced fuel capacity was marketed as the G500. Gulfstream ceased production of the G550 in July 2021. Development The G550 (GV-SP) with improved engines received its FAA type certificate on August 14, 2003. In 2014, Gulfstream looked at a re-engine with the Rolls-Royce Pearl BR700 development announced in May 2018 for the new Global Express 5500 and 6500 variants but preferred the BR725-powered, 7,500 nmi G650. The 500th Gulfstream G550 aircraft was delivered in May 2015. Deliveries went from 50 aircraft in 2011 to 19 in 2016 and with 40 units for sale in a fleet of 540. Valuations of the G550 are falling: a 10-year-old G550 valued $28 million a year before is worth $18-$20 million in January 2017, while a two-year-old went from $40 to $35 million. In May 2017, early 2003 G550s were valued at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerosols
An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of anthropogenic aerosols include particulate air pollutants, mist from the discharge at hydroelectric dams, irrigation mist, perfume from atomizers, smoke, steam from a kettle, sprayed pesticides, and medical treatments for respiratory illnesses. When a person inhales the contents of a vape pen or e-cigarette, they are inhaling an anthropogenic aerosol. The liquid or solid particles in an aerosol have diameters typically less than 1 μm (larger particles with a significant settling speed make the mixture a suspension, but the distinction is not clear-cut). In general conversation, ''aerosol'' often refers to a dispensing system that delivers a consumer product from a can. Diseases can spread by means of small droplets in the breat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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