In meteorology, what is measured in 'Oktas'?
"Okta In meteorology, an okta is a unit of measurement used to describe the amount of cloud cover at any given location such as a weather station. Sky conditions are estimated in terms of how many eighths of the sky are covered in cloud, ranging from 0 oktas (completely clear sky) through to 8 oktas (completely overcast). In addition, in the SYNOP code there is an extra cloud cover indicator '9' indicating that the sky is totally obscured (i.e. hidden from view), usually due to dense fog or heavy snow. When used in weather charts, okta measurements are shown by"
"description of the cloud layers and opacities, in eighths (oktas). For example, CU5 would indicate a cumulus layer with opacity."" Cloud coverage is reported by the number of 'oktas' (eighths) of the sky that is occupied by cloud. This is reported as: METARs can be expressed concisely using so-called ""aviation flight categories"", which indicates what classes of flight can operate at each airport by referring to the visibility and ceiling in each METAR. Four categories are used in the U.S.: METAR abbreviations used in the WX section. Remarks section will also include began and end times of the weather events."
"Δ18O In geochemistry, paleoclimatology and paleoceanography ""δ""O or delta-O-18 is a measure of the ratio of stable isotopes oxygen-18 (O) and oxygen-16 (O). It is commonly used as a measure of the temperature of precipitation, as a measure of groundwater/mineral interactions, and as an indicator of processes that show isotopic fractionation, like methanogenesis. In paleosciences, O:O data from corals, foraminifera and ice cores are used as a proxy for temperature. The definition is, in ""per mil"" (‰, parts per thousand): where the standard has a known isotopic composition, such as Vienna Standard Mean Ocean Water (VSMOW). The fractionation can arise"
"Cloud cover Cloud cover (also known as cloudiness, cloudage, or cloud amount) refers to the fraction of the sky obscured by clouds when observed from a particular location. Okta is the usual unit of 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. The global cloud cover averages around 0.68 when analyzing clouds with optical depth larger than 0.1. This value is lower (0.56) when considering clouds with an optical depth larger than 2, and higher when"
"Octant (instrument) The octant, also called reflecting quadrant, is a measuring instrument used primarily in navigation. It is a type of reflecting instrument. The name ""octant"" derives from the Latin ""octans"" meaning ""eighth part of a circle"", because the instrument's arc is one eighth of a circle. ""Reflecting quadrant"" derives from the instrument using mirrors to reflect the path of light to the observer and, in doing so, doubles the angle measured. This allows the instrument to use a one-eighth of a turn to measure a quarter-turn or quadrant. Isaac Newton's reflecting quadrant was invented around 1699. A detailed description"
"Octant (plane geometry) In plane geometry, octant is a circular sector obtained by division of the full circle into 8 equal parts, hence the name. It is a sector with the central angle of 45°. Most commonly, octants are seen on the compass rose. Traditionally wind direction is given as one of the 8 octants (N, NE, E, SE, S, SW, W, NW) because that is more precise than merely giving one of the 4 quadrants, and the wind vane typically does not have enough accuracy to bother with more precise indication. The name of the instrument ""octant"" comes from"
"assumes they can be considered separate layers, oxygen above water, with different characteristic temperatures and opacities. The temperature and opacity of oxygen in the upper atmosphere do not vary much seasonally and are assumed to be constant at 255 K and 0.378, respectively, at the signal frequency. The remaining parameters in the model, the temperature and opacity of water and the fraction of the received power from the sky, are determined through antenna tippings (measurements of the intensity of the sky signal as a function of elevation) at least once per six-hour observing shift, and more frequently if the weather"
"Epsilon Octantis Epsilon Octantis, Latinized from ε Octantis, is a star in the southern circumpolar constellation of Octans. It is a faintly visible to the naked eye with an apparent visual magnitude of 5.09. The annual parallax shift of 11.22 mas yields a distance estimate of around 291 light years. It is moving further from the Sun with a radial velocity of +11.7 km/s. This is an evolved, cool red giant star with a stellar classification of class M5III. It is a semiregular variable with a magnitude range of 4.58 to 5.3 and a (poorly defined) period around 55 days."
"Odin-OSIRIS OSIRIS (Optical Spectrograph and InfraRed Imager System) is an instrument that measures vertical profiles of spectrally dispersed, limb scattered sunlight from the upper troposphere into the lower mesosphere. OSIRIS is one of two instruments on the Odin satellite, launched February, 2001 (the other instrument being a sub-mm radiometer) into a sun-synchronous, 6 pm/6 am local time orbit at 600 km. This restricts OSIRIS sunlit observations to the Northern hemisphere in May, June, July August and the Southern hemisphere in November, December, January and February. Global coverage from 82°S to 82°N occurs on the months adjoining the equinoxes. OSIRIS measurements"
"Odin-OSIRIS OSIRIS (Optical Spectrograph and InfraRed Imager System) is an instrument that measures vertical profiles of spectrally dispersed, limb scattered sunlight from the upper troposphere into the lower mesosphere. OSIRIS is one of two instruments on the Odin satellite, launched February, 2001 (the other instrument being a sub-mm radiometer) into a sun-synchronous, 6 pm/6 am local time orbit at 600 km. This restricts OSIRIS sunlit observations to the Northern hemisphere in May, June, July August and the Southern hemisphere in November, December, January and February. Global coverage from 82°S to 82°N occurs on the months adjoining the equinoxes. OSIRIS measurements"
"the right aligns the values of δO (right scale) with the reported temperature variations from the Vostok ice core (left scale), following Petit et al. (1999). Δ18O In geochemistry, paleoclimatology and paleoceanography ""δ""O or delta-O-18 is a measure of the ratio of stable isotopes oxygen-18 (O) and oxygen-16 (O). It is commonly used as a measure of the temperature of precipitation, as a measure of groundwater/mineral interactions, and as an indicator of processes that show isotopic fractionation, like methanogenesis. In paleosciences, O:O data from corals, foraminifera and ice cores are used as a proxy for temperature. The definition is, in"
"such as the Amazon Rainforest and some others are almost always clear such as the Sahara Desert. Cloud cover Cloud cover (also known as cloudiness, cloudage, or cloud amount) refers to the fraction of the sky obscured by clouds when observed from a particular location. Okta is the usual unit of 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. The global cloud cover averages around 0.68 when analyzing clouds with optical depth larger than 0.1. This"
"weather thresholds (e.g. conditions change from visual meteorological conditions to instrument meteorological conditions). The basic weather elements observed are: sky condition, visibility, present weather, obstructions to vision, pressure, temperature, dew point, wind direction and speed, precipitation accumulation, and selected significant remarks. The coded observations are issued as METARs and look similar to this: Getting more information on the atmosphere, more frequently, and from more locations is the key to improving forecasts and warnings. Due to the large installation and operating costs associated with ASOS, the stations are widely spaced. Therefore, the Cooperative Observer Program (COOP), a network of approximately 11,000"
"Octans Octans is a faint constellation located in the deep southern sky. Its name is Latin for the eighth part of a circle, but it is named after the octant, a navigational instrument. The constellation was devised by French astronomer Nicolas Louis de Lacaille in 1752, and it remains one of the 88 modern constellations. Octans was one of 14 constellations created by French astronomer Nicolas Louis de Lacaille during his expedition to the Cape of Good Hope, and was originally named ""l’Octans de Reflexion"" (“the reflecting octant”) in 1752, after he had observed and catalogued almost 10,000 southern stars"
"The Ocean Color and Temperature Scanner (OCTS) is a whisk broom radiometer developed by NASDA. The Advanced Visible and Near Infrared Radiometer (AVNIR), an optoelectronic scanning radiometer with CCD detectors, was also produced by NASDA. The NASA Scatterometer (NSCAT), developed with the Jet Propulsion Laboratory, used fan-beam Doppler signals to measure wind speeds over bodies of water. The Total Ozone Mapping Spectrometer (TOMS) was built by CNES to study changes to Earth's ozone layer. The Polarization and Directionality of the Earth's Reflectance (POLDER) device was also developed by CNES, and was also launched on ADEOS II. The Improved Limb Atmospheric"
"Sigma Octantis Sigma Octantis (σ Octantis, abbreviated Sig Oct, σ Oct), also named Polaris Australis, is the current South Star. Its position near the southern celestial pole makes it the southern hemisphere's pole star. This is a solitary star in the southern circumpolar constellation of Octans. Located approximately 281 light-years from Earth, it is classified as a giant star with a spectral type of F0 III. Sigma Octantis is a Delta Scuti variable, with its average magnitude of 5.47 varying by about 0.03 magnitudes every 2.33 hours. ""σ Octantis"" (Latinised to ""Sigma Octantis"") is the star's Bayer designation. As the"
"Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats NASA's Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission is a constellation of small satellites that will measure temperature and moisture profiles and precipitation in tropical systems with unprecedented temporal frequency. This data will enable scientists to study the dynamic processes that occur in the inner core of the storm resulting in rapid genesis and intensification. William Blackwell of the Massachusetts Institute of Technology’s Lincoln Laboratory in Lexington is the principal investigator. The TROPICS CubeSats will get very frequent measurements,"
"Oxygen-18 Oxygen-18 () is a natural, stable isotope of oxygen and one of the environmental isotopes. In ice cores, mainly Arctic and Antarctic, the ratio of to (known as δ) can be used to determine the temperature of precipitation through time. Assuming that atmospheric circulation and elevation has not changed significantly over the poles, the temperature of ice formation can be calculated as equilibrium fractionation between phases of water that is known for different temperatures. Water molecules are also subject to Rayleigh fractionation as atmospheric water moves from the equator poleward which results in progressive depletion of O-18, or lower"
"Automated Occultation Survey. The data volume is expected to be over 300 terabytes per year. Taiwanese–American Occultation Survey The Taiwanese–American Occultation Survey (TAOS) is a robotic survey of the Outer Solar System. TAOS uses an array of four 50 cm aperture telescopes to monitor background stars awaiting the alignment of an Outer Solar System with a star target: an ""occultation"". Small objects in the Outer Solar System that are too small to be observed by direct observations at this time can be probed with this technique. Occultation surveys take advantage of diffraction effects during the transit of the occulting object"
"the fact that it is based on 1/8th of the circle. Octant (plane geometry) In plane geometry, octant is a circular sector obtained by division of the full circle into 8 equal parts, hence the name. It is a sector with the central angle of 45°. Most commonly, octants are seen on the compass rose. Traditionally wind direction is given as one of the 8 octants (N, NE, E, SE, S, SW, W, NW) because that is more precise than merely giving one of the 4 quadrants, and the wind vane typically does not have enough accuracy to bother with"
"Outside air temperature In aviation terminology, the outside air temperature (OAT) or static air temperature (SAT) refers to the temperature of the air around an aircraft, but unaffected by the passage of the aircraft through it. The outside air temperature is used in many calculations pertaining to flight planning, some of them being takeoff performance, density altitude, cruise performance and go-around performance. In most texts, the abbreviation, ""OAT"" is used. Most performance and flight planning graphs and tables use either degrees Celsius or Fahrenheit or both. The Kelvin scale, however, is used for Mach number calculations. For example, the speed"
"reporting system in use in the United States differs from the one used by the World Meteorological Organization (WMO) in that wind speeds are delivered in knots (instead of meters per second), water-equivalent precipitation in hundredths of an inch, and altimeter setting in the customary inches of mercury (instead of hectopascals). Furthermore, temperatures are reported in whole degrees Fahrenheit but are converted to Celsius when encoded in METAR reports. Most synoptic observation charts are expressed in SI units, except for the aforementioned wind speeds, which must be converted for the purposes of calculation. Upper-air temperature charts typically use the Celsius"
"Oort constants The Oort constants (discovered by Jan Oort) formula_1 and formula_2 are empirically derived parameters that characterize the local rotational properties of our galaxy, the Milky Way, in the following manner: where formula_4 and formula_5 are the rotational velocity and distance to the Galactic center, respectively, measured at the position of the Sun, and and are the velocities and distances at other positions in our part of the galaxy. As derived below, and depend only on the motions and positions of stars in the solar neighborhood. As of 2018, the most accurate values of these constants are formula_1 ="
"Outer Solar System Origins Survey The Outer Solar System Origins Survey (OSSOS) is an astronomical survey and observing program aimed at discovering and tracking trans-Neptunian objects located in the outermost regions of the Solar System beyond the orbit of Neptune. OSSOS is designed in way that observational biases can be characterized, allowing the numbers and orbits of detected objects to be compared using a survey simulator to the populations predicted in dynamical simulations of the emplacement of trans-Neptunian objects. Conducted at the Canada-France-Hawaii telescope at Mauna Kea Observatories in Hawaii, the survey has discovered 39 numbered objects as of 2018,"
"Octant (solid geometry) An octant in solid geometry is one of the eight divisions of a Euclidean three-dimensional coordinate system defined by the signs of the coordinates. It is similar to the two-dimensional quadrant and the one-dimensional ray. The generalization of an octant is called orthant. A convention for naming an octant is to give its list of signs, e.g. ( + − − ) or ( − + − ). Octant ( + + + ) is sometimes referred to as the ""first octant"", although similar ordinal name descriptors are not defined for the other seven octants. The advantages"
"The star has 1.34 times the mass of the Sun and has expanded to around 112 times the Sun's radius. It is radiating 1,819 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,560 K. Epsilon Octantis Epsilon Octantis, Latinized from ε Octantis, is a star in the southern circumpolar constellation of Octans. It is a faintly visible to the naked eye with an apparent visual magnitude of 5.09. The annual parallax shift of 11.22 mas yields a distance estimate of around 291 light years. It is moving further from the Sun with a radial velocity"
"by KNMI (principal investigator Prof. Dr. P. F. Levelt), in close co-operation with NASA and the Finnish Meteorological Institute. Ozone monitoring instrument The ozone monitoring instrument (OMI) is a visual and ultraviolet spectrometer aboard the NASA Aura spacecraft. OMI can distinguish between aerosol types, such as smoke, dust, and sulfates, and can measure cloud pressure and coverage, which provide data to derive tropospheric ozone. OMI follows in the heritage of TOMS, SBUV, GOME, SCIAMACHY, and GOMOS. It is a wide-field-imaging spectrometer with a 114° across-track viewing angle range that provides a 2600 km wide swath, enabling measurements with a daily"
"Ocean data acquisition system An ocean data acquisition system (ODAS) is a set of instruments deployed at sea to collect as much meteorological and oceanographic data as possible. With their sensors, these systems deliver data both on the state of the ocean itself and the surrounding lower atmosphere. The use of microelectronics and technologies with efficient energy consumption allows to increase the types and numbers of sensor deployed on a single device. According to Intergovernmental Oceanographic Commission and World Meteorological Organization (WMO), ""ODAS means a structure, platform, installation, buoy, or other device, not being a ship, together with its appurtenant"
"Orbital forcing Orbital forcing is the effect on climate of slow changes in the tilt of the Earth's axis and shape of the orbit (see Milankovitch cycles). These orbital changes change the total amount of sunlight reaching the Earth by up to 25% at mid-latitudes (from 400 to 500 Wm at latitudes of 60 degrees). In this context, the term ""forcing"" signifies a physical process that affects the Earth's climate. This mechanism is believed to be responsible for the timing of the ice age cycles. A strict application of the Milankovitch theory does not allow the prediction of a ""sudden"""
"Beta Octantis Beta Octantis, Latinized from β Octantis, is a probable astrometric binary star system in the southern circumpolar constellation of Octans. It is faintly visible to the naked eye with an apparent visual magnitude of 4.13. Based upon an annual parallax shift of 21.85 mas as seen from Earth, it is located about 149 light years from the Sun. It is moving away from the Sun with a radial velocity of +19 km/s. Based upon a stellar classification of A9IV-V, the visible component is an evolving, white-hued A-type star with a spectrum that shows mixed traits of a main"
"and land topography and vegetation characteristics, with an active service period from February 2003 to October 2009. The European Space Agency Soil Moisture and Ocean Salinity (SMOS) mission is the first orbit mission to measure salinity of the Earth’s surface and able to show data through most clouds and during darkness. The sea ice volume is calculated with the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS). The E-M Bird ice thickness meter, designed by the Alfred Wegener Institute for Polar and Marine Research, is carried aloft by helicopter and measures ice thickness with a combination of a pair of"
"at the summit as part of their ""Liegekur"" (""deckchair cure""). The summit observatory, which is located at an altitude of , is an important scientific measuring station operated by the Institute for Meteorology and Climate Research of Karlsruhe Institute of Technology. Since 1972 it has measured a variety of atmospheric and climatic phenomena, including the levels of ozone, nitric oxide, sulphur dioxide and various hydrocarbons in the atmosphere as well as meteorological data such as the levels of temperature, dew point, relative humidity, pressure, wind, global and direct irradiance. It became part of the World Meteorological Organization's Background Air Pollution"
"sequence and a subgiant star. It has an estimated 2.27 times the mass of the Sun and 3.2 times the Sun's radius. The star is around 500 million years old with a projected rotational velocity of 49 km/s. It is radiating 42 times the Sun's luminosity from its photosphere at an effective temperature of 8,006 K. Beta Octantis Beta Octantis, Latinized from β Octantis, is a probable astrometric binary star system in the southern circumpolar constellation of Octans. It is faintly visible to the naked eye with an apparent visual magnitude of 4.13. Based upon an annual parallax shift of"