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Sea Ice Thickness
Sea ice thickness spatial extent, and open water within sea ice packs can vary rapidly in response to weather and climate. Sea ice concentration are measured by satellites, with the Special Sensor Microwave Imager / Sounder (SSMIS), and the ''European Space Agency's'' Cryosat-2 satellite to map the thickness and shape of the Earth's polar ice cover. The sea ice volume is calculated with the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS), which blends satellite-observed data, such as sea ice concentrations into model calculations to estimate sea ice thickness and volume. Sea ice thickness determines a number of important fluxes such as heat flux between the air and ocean surface—see below—as well as salt and fresh water fluxes between the ocean since saline water ejects much of its salt content when frozen—see sea ice growth processes. It is also important for navigators on icebreakers since there is an upper limit to the thickness of ice any ship can sail th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Ice
Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the Arctic ecology, including the ocean's ecosystems. Due to the action of winds, currents and temperature fluctuations, sea ice is very dynamic, leading to a wide variety of ice types and features. Sea ice may be contrasted with icebergs, which are chunks of ice shelves or glaciers that calve into the ocean. Depending on location, sea ice expanses may also incorporate icebergs. General features and dynamics Sea ice does not simply grow a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ICESat
ICESat (Ice, Cloud, and land Elevation Satellite) was a NASA satellite mission for measuring ice sheet mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics. It operated as part of NASA's Earth Observing System (EOS). ICESat was launched 13 January 2003 on a Delta II launch vehicle from Vandenberg Air Force Base in California into a near-circular, near-polar orbit with an altitude of approximately . It operated for seven years before being retired in February 2010, after its scientific payload shut down and scientists were unable to restart it. The ICESat mission was designed to provide elevation data needed to determine ice sheet mass balance as well as cloud property information, especially for stratospheric clouds common over polar areas. It provides topography and vegetation data around the globe, in addition to the polar-specific coverage over the Greenland and Antarctic ice sheets. The satellite was found useful in assessing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Remote Sensing
Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring information about Earth and other planets. Remote sensing is used in numerous fields, including geography, land surveying and most Earth science disciplines (e.g. hydrology, ecology, meteorology, oceanography, glaciology, geology); it also has military, intelligence, commercial, economic, planning, and humanitarian applications, among others. In current usage, the term ''remote sensing'' generally refers to the use of satellite- or aircraft-based sensor technologies to detect and classify objects on Earth. It includes the surface and the atmosphere and oceans, based on propagated signals (e.g. electromagnetic radiation). It may be split into "active" remote sensing (when a signal is emitted by a satellite or aircraft to the object and its reflection dete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate
Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological variables that are commonly measured are temperature, humidity, atmospheric pressure, wind, and precipitation. In a broader sense, climate is the state of the components of the climate system, including the atmosphere, hydrosphere, cryosphere, lithosphere and biosphere and the interactions between them. The climate of a location is affected by its latitude/longitude, terrain, altitude, land use and nearby water bodies and their currents. Climates can be classified according to the average and typical variables, most commonly temperature and precipitation. The most widely used classification scheme was the Köppen climate classification. The Thornthwaite system, in use since 1948, incorporates evapotranspiration along wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Ice
Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the Arctic ecology, including the ocean's ecosystems. Due to the action of winds, currents and temperature fluctuations, sea ice is very dynamic, leading to a wide variety of ice types and features. Sea ice may be contrasted with icebergs, which are chunks of ice shelves or glaciers that calve into the ocean. Depending on location, sea ice expanses may also incorporate icebergs. General features and dynamics Sea ice does not simply grow a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Ice Growth Processes
Sea ice is a complex composite composed primarily of pure ice in various states of crystallization along with air bubbles and included pockets of brine. Understanding its growth processes is important both for climate scientists for use in simulations as well remote sensing specialists since the composition and microstructural properties of the ice ultimately affect how it interacts with electromagnetic radiation. Sea ice growth models for predicting the ice distribution and extent are also valuable for shipping concerns. An ice growth model can be combined with remote sensing measurements in an assimilation model as a means of generating more accurate ice charts. Overview Several formation mechanisms of sea ice have been identified. At its earliest stages, sea ice consists of elongated, randomly oriented crystals. This is called frazil and mixed with water in the unconsolidated state is known as grease ice. If wave and wind conditions are calm, these crystals will consoli ... [...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] |
Metal Detector
A metal detector is an instrument that detects the nearby presence of metal. Metal detectors are useful for finding metal objects on the surface, underground, and under water. The unit itself, consist of a control box, and an adjustable shaft, which holds a pickup coil, which can vary in shape and size. If the pickup coil comes near a piece of metal, the control box will register its presence by a changing tone, a flashing light, and or by a needle moving on an indicator. Usually the device gives some indication of distance; the closer the metal is, the higher the tone in the earphone or the higher the needle goes. Another common type are stationary "walk through" metal detectors used at access points in prisons, courthouses, airports and psychiatric hospitals to detect concealed metal weapons on a person's body. The simplest form of a metal detector consists of an oscillator producing an alternating current that passes through a coil producing an alternating magnetic field. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inductance
Inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. The flow of electric current creates a magnetic field around the conductor. The field strength depends on the magnitude of the current, and follows any changes in current. From Faraday's law of induction, any change in magnetic field through a circuit induces an electromotive force (EMF) (voltage) in the conductors, a process known as electromagnetic induction. This induced voltage created by the changing current has the effect of opposing the change in current. This is stated by Lenz's law, and the voltage is called '' back EMF''. Inductance is defined as the ratio of the induced voltage to the rate of change of current causing it. It is a proportionality factor that depends on the geometry of circuit conductors and the magnetic permeability of nearby materials. An electronic component designed to add inductance to a circuit is called an inductor. It typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inductor
An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. An inductor typically consists of an insulated wire wound into a coil. When the current flowing through the coil changes, the time-varying magnetic field induces an electromotive force (''emf'') (voltage) in the conductor, described by Faraday's law of induction. According to Lenz's law, the induced voltage has a polarity (direction) which opposes the change in current that created it. As a result, inductors oppose any changes in current through them. An inductor is characterized by its inductance, which is the ratio of the voltage to the rate of change of current. In the International System of Units (SI), the unit of inductance is the henry (H) named for 19th century American scientist Joseph Henry. In the measurement of magnetic circuits, it is equivalent to . Inductors have values that typically ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Wegener Institute For Polar And Marine Research
The Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (German: ''Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung'') is located in Bremerhaven, Germany, and a member of the Helmholtz Association of German Research Centres. It conducts research in the Arctic, the Antarctic, and the high and mid latitude oceans. Additional research topics are: North Sea research, marine biological monitoring, and technical marine developments. The institute was founded in 1980 and is named after meteorologist, climatologist, and geologist Alfred Wegener. History The foundation of the AWI happened in a political environment that was characterized by system competition between East and West. The GDR had been conducting its own Antarctic research for decades. In the 1970s it became clear that there would be one scarcity of biological- and mineral resources. Also due to the experience of the oil crisis of 1973, the Federal Republic of Germany de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proceedings Of The IEEE
The ''Proceedings of the IEEE'' is a monthly peer-reviewed scientific journal published by the Institute of Electrical and Electronics Engineers (IEEE). The journal focuses on electrical engineering and computer science. According to the ''Journal Citation Reports'', the journal has a 2017 impact factor of 9.107, ranking it sixth in the category "Engineering, Electrical & Electronic." In 2018, it became fifth with an enhanced impact factor of 10.694. History of the Proceedings The journal was established in 1909, known as the ''Proceedings of the Wireless Institute''. Six issues were published under this banner by Greenleaf Pickard and Alfred Goldsmith. Then in 1911, a merger between the Wireless Institute (New York) and the Society of Wireless Telegraph Engineers (Boston) resulted in a society named the Institute of Radio Engineers (IRE). In January 1913 newly formed IRE published the first issue of the ''Proceedings of the IRE''. Later, a 1000-page special issue commemor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
