Satellites do not measure temperature directly. They measure radiances in various wavelength bands, from which temperature may be inferred. The resulting temperature profiles depend on details of the methods that are used to obtain temperatures from radiances. As a result, different groups that have analyzed the satellite data have obtained different temperature data (see Microwave Sounding Unit temperature measurements).
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RTTOV - the fast radiative transfer model for calculations of radiances for satellite infrared or microwave nadir scanning radiometers (see push broom scanner). Given an atmospheric profile of temperature, variable gas concentrations, cloud and surface properties RTTOV calculates radiances and brightness temperatures. The only mandatory input is water vapour. Optionally ozone, carbon dioxide, nitrous oxide, methane and carbon monoxide can be variable with all other constituents assumed to be constant.
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They measure radiances in various wavelength bands, which must then be mathematically inverted to obtain indirect inferences of temperature. The resulting temperature profiles depend on details of the methods that are used to obtain temperatures from radiances. As a result, different groups that have analyzed the satellite data have obtained different temperature trends. Among these groups are Remote Sensing Systems (RSS) and the University of Alabama in Huntsville (UAH).
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The Community Radiative Transfer Model (CRTM) is a fast radiative transfer model for calculations of radiances for satellite infrared or microwave radiometers. Given an atmospheric profile of temperature, variable gas concentrations, cloud and surface properties CRTM calculates radiances and brightness temperatures. The only mandatory inputs in terms of variable gases are water vapor and ozone. The range of temperatures and water vapour concentrations over which the optical depth computations are valid depends on the training datasets which were used.
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Data sets regarding cloud properties are gathered using satellites, such as MODIS, POLDER, CALIPSO or ATSR. The instruments measure the radiances of the clouds, from which the relevant parameters can be retrieved. This is usually done by using inverse theory. The method of detection is based on the fact that the clouds tend to appear brighter and colder than the land surface.
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Streamer is a radiative transfer code (Key and Schweiger, 1988) to calculate radiances (intensities) or irradiances in the atmosphere. The code uses N-stream approximation to the radiative transfer equations (Stamnes et al. 1988) and allows for flexible choice of bands. The code can be used both for satellite radiance applications and estimates of heating rates in both cloudy and non-cloudy atmosphere.
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030 open access Another common field of application is in a weather or climate model, where the radiative forcing is calculated for greenhouse gases, aerosols, or clouds. In such applications, radiative transfer codes are often called radiation parameterization. In these applications, the radiative transfer codes are used in forward sense, i.e. on the basis of known properties of the atmosphere, one calculates heating rates, radiative fluxes, and radiances.
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The Scanning Multichannel Microwave Radiometer (SMMR) [pronounced simmer] was a five-frequency microwave radiometer flown on the Seasat and Nimbus 7 satellites. Both were launched in 1978, with the Seasat mission lasting less than six months until failure of the primary bus. The Nimbus 7 SMMR lasted from 25 October 1978 until 20 August 1987. It measured dual-polarized microwave radiances, at 6.63, 10.69, 18.0, 21.0, and 37.0 GHz, from the Earth's atmosphere and surface.
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They measure radiances in various wavelength bands. Since 1978 microwave sounding units (MSUs) on National Oceanic and Atmospheric Administration polar orbiting satellites have measured the intensity of upwelling microwave radiation from atmospheric oxygen, which is related to the temperature of broad vertical layers of the atmosphere. Measurements of infrared radiation pertaining to sea surface temperature have been collected since 1967. Satellite datasets show that over the past four decades the troposphere has warmed and the stratosphere has cooled.
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Since 1982, satellites have been increasingly utilized to measure SST and have allowed its spatial and temporal variation to be viewed more fully. For example, changes in SST monitored via satellite have been used to document the progression of the El Niño-Southern Oscillation since the 1970s. Over land the retrieval of temperature from radiances is harder, because of inhomogeneities in the surface. Studies have been conducted on the urban heat island effect via satellite imagery.
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The following applies mainly to passive sensors, but has some applicability to active sensors. Typically, there is a vector of values of the quantity to be retrieved, \vec x, called the state vector and a vector of measurements, \vec y. The state vector could be temperatures, ozone number densities, humidities etc. The measurement vector is typically counts, radiances or brightness temperatures from a radiometer or similar detector but could include any other quantity germain to the problem.
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Eilistraee appears as a drow female of extraordinary beauty. She is 9 feet (2.7 meters) tall, with long, strong, graceful limbs and a glossy, obsidian-dark skin. Her face is like that of her mother, Lolth, with delicately sculpted features and shape, save for her large eyes and ankle-length hair, which are of a glowing silvery hue. She usually appears unclad, cloaked only by her hair and silvery radiances that are ever-moving about her body.
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Beginning in the late 1950s, Pousette-Dart experimented with building form through small, individual dabs of color, creating paintings and works on paper that exhibit all-over, field-like compositions. By the 1960s, he concentrated on large-scale works composed of thick layers of such gestural marks, evoking pulsating, glowing allusions to space. Paintings known as Hieroglyphs, Presences and Radiances display dense fields and calligraphic structures that emerge and recede visually. Works of the 1970s and 1980s often exhibit large shapes—orbs and geometric forms— that serve as mandala-like focal points.
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However, he treated it as an infinite collection of vectors, one per direction impinging on the point, with lengths proportional to their radiances. Integrating these vectors over any collection of lights, or over the entire sphere of directions, produces a single scalar value—the total irradiance at that point, and a resultant direction. The figure at right, reproduced from Gershun's paper, shows this calculation for the case of two light sources. In computer graphics, this vector-valued function of 3D space is called the vector irradiance field (Arvo, 1994).
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CIMEL Sunphotometer AERONET - the AERONET (AErosol RObotic NETwork) is a network of ground-based sun photometers which measure atmospheric aerosol properties. The measurement system is a solar-powered CIMEL Electronique 318A spectral radiometer that measures Sun and sky radiances at a number of fixed wavelengths within the visible and near-infrared spectrum. There is one sea- based reading location aboard the E/V Nautilus, the exploration vessel operated by Dr. Robert Ballard and the Sea Research Foundation. Two readings per day are taken aboard the ship while it is in operation.
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Humbaba is first mentioned in Tablet II of the Epic of Gilgamesh. After Gilgamesh and Enkidu become friends following their initial fight, they set out on an adventure to the Cedar Forest beyond the seventh mountain range, to slay Humbaba (Huwawa): "Enkidu," Gilgamesh vows, "since a man cannot pass beyond the final end of life, I want to set off into the mountains, to establish my renown there." Gilgamesh tricks the monster into giving away his seven "radiances" by offering his sisters as wife and concubine. When Humbaba's guard is down, Gilgamesh punches him and captures the monster.
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He was by 1982 working in an artists' colony in the East End of London having bought the defunct Spratts Dog Food warehouse in Bow whilst continuing his teaching role. In 1996 his solo show "Reflections, Orbits and Radiances" in the sympathetic surroundings of the De La Warr Pavilion in Bexhill-on-Sea, Sussex drew mainly on work done in the period 1992-96. In the catalogue, Christopher Lloyd, Surveyor of the Queen's Pictures, considered that it was "difficult to think of a more appropriate setting for John Copnall's paintings" than this light- filled example of pioneering mid-1930s architecture. Copnall was elected to the London Group in 1988.
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For MODIS/AVHRR SNO occurrences, it was determined that the ratio of AVHRR to MODIS radiances in both Ch1 and Ch2 are modeled well by a second-order polynomial of the radio of MODIS reflectances in channels 17 and 18. Channels 17 and 18 are located in a spectral region (0.94mm) sensitive to atmospheric water vapor, a quantity that affects the accurate calibration of AVHRR Ch. 2. Using the Ch17 to Ch 18 ratio, an accurate guess at the total precipitable water (TPW) is obtained to further increase the accuracy of MODIS to AVHRR SNO calibrations. The Libyan Desert and Dome-C calibration sites are used when MODIS/AVHRR SNOs do not occur.
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GERB-SEVIRI Synergy As ERB fluxes from the CERES instruments are paired with MODIS imager cloud retrievals, it was always the intention to tie GERB SW and LW measurements with results from the Spinning Enhanced Visible and Infra-Red Imager (SEVIRI) primary device on the MSG platforms. In addition to the cloud/aerosol retrievals from the narrow-band SEVIRI instrument, the high spatial resolution imager data is combined with the accuracy of GERB to perform resolution enhancement of climate driving fluxes to better evaluate climate model simulations of cloud formation/dissipation and know how they may speed up or slow down climate change. SEVIRI radiances are also used in the GERB un-filtering process to help estimate the spectral shape of the scene being viewed. Data Access In addition to the Rutherford GGSPS download site, a new access hub is being setup at the Centre for Environmental Data Analysis (CEDA), which is also listed in the URLs below that will allow access to GERB files.
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