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- Author or Editor: A. F. Beaubien x
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Abstract
Three approaches to the design of total (global) solar pyranometers that employ new technologies and materials of manufacture are described. The pyranometers are designed to meet or exceed the requirements for high quality instruments as classified by the World Meteorological Organization’s Guide to Meteorological Instruments and Methods of Observation. A pyranometer employing linear thin-film platinum resistance thermometers to measure the temperature rise of an optically black metal surface is presented; a second design utilizes a bismuth telluride thermopile to measure the temperature rise of an optically black silver disc, and a third design uses an optically black, fast-response thin film bismuth antimony thermopile with diffusing foreoptic for determining the solar irradiance level. All three designs employ optically black radiation receiving surfaces. The structure of the radiation detection schemes are presented and electronic circuitry, when required, is described. For each of the instrument types, the measured time responses, ambient temperature response, cosine response, and azimuth asymmetry response are presented. Special-purpose apparatus used for determining cosine response and azimuth response is presented in the .
Abstract
Three approaches to the design of total (global) solar pyranometers that employ new technologies and materials of manufacture are described. The pyranometers are designed to meet or exceed the requirements for high quality instruments as classified by the World Meteorological Organization’s Guide to Meteorological Instruments and Methods of Observation. A pyranometer employing linear thin-film platinum resistance thermometers to measure the temperature rise of an optically black metal surface is presented; a second design utilizes a bismuth telluride thermopile to measure the temperature rise of an optically black silver disc, and a third design uses an optically black, fast-response thin film bismuth antimony thermopile with diffusing foreoptic for determining the solar irradiance level. All three designs employ optically black radiation receiving surfaces. The structure of the radiation detection schemes are presented and electronic circuitry, when required, is described. For each of the instrument types, the measured time responses, ambient temperature response, cosine response, and azimuth asymmetry response are presented. Special-purpose apparatus used for determining cosine response and azimuth response is presented in the .
Abstract
Characteristics of an instrument for measuring solar ultraviolet-B irradiance are presented together with a description of the instrument. The instrument measures direct and scattered broadband ultraviolet irradiance (wavelengths between 280 and 330 nm) from the hemisphere of the sky. Measurement technique employs colored glass filters in combination with a fluorescing ultraviolet-sensitive phosphor. Thermal regulation is used to significantly reduce measurement errors introduced by changes in ambient temperature.
Abstract
Characteristics of an instrument for measuring solar ultraviolet-B irradiance are presented together with a description of the instrument. The instrument measures direct and scattered broadband ultraviolet irradiance (wavelengths between 280 and 330 nm) from the hemisphere of the sky. Measurement technique employs colored glass filters in combination with a fluorescing ultraviolet-sensitive phosphor. Thermal regulation is used to significantly reduce measurement errors introduced by changes in ambient temperature.
The U.S. Department of Agriculture's Ultraviolet (UV) Radiation Monitoring Program has been measuring UV radiation since 1994. The initial network of 12 stations employed broadband meters to measure UVB irradiance and included ancillary measurements of temperature, humidity, and irradiance at seven wavelengths in the visible produced by a Multi-Filter Rotating Shadowband Radiometer (MFRSR). Since that beginning the network has expanded to more than 20 stations and the broadband meters have been supplemented with a seven-wavelength Ultraviolet Multi-Filter Rotating Shadowband Radiometer (UV-MFRSR). The network has been designed to include 30 stations, each with a full complement of instrumentation. Annual characterizations of the network's filter radiometers indicate that gradual shifts in instrument response are manageable but must be accounted for to achieve accurate and precise measurements of UV irradiance. The characterization and calibration of the filter instruments is discussed along with filter stability and instrument precision. Broadband instruments are shown to be quite stable and collocated instruments are shown to agree to within 2.3% for zenith angles less than 80° under all sky conditions. Preliminary investigations into the accuracy of the UV-MFRSR calibrated with the Langley method are presented and successful column ozone retrievals are demonstrated with the UV-MFRSR under clear skies.
The U.S. Department of Agriculture's Ultraviolet (UV) Radiation Monitoring Program has been measuring UV radiation since 1994. The initial network of 12 stations employed broadband meters to measure UVB irradiance and included ancillary measurements of temperature, humidity, and irradiance at seven wavelengths in the visible produced by a Multi-Filter Rotating Shadowband Radiometer (MFRSR). Since that beginning the network has expanded to more than 20 stations and the broadband meters have been supplemented with a seven-wavelength Ultraviolet Multi-Filter Rotating Shadowband Radiometer (UV-MFRSR). The network has been designed to include 30 stations, each with a full complement of instrumentation. Annual characterizations of the network's filter radiometers indicate that gradual shifts in instrument response are manageable but must be accounted for to achieve accurate and precise measurements of UV irradiance. The characterization and calibration of the filter instruments is discussed along with filter stability and instrument precision. Broadband instruments are shown to be quite stable and collocated instruments are shown to agree to within 2.3% for zenith angles less than 80° under all sky conditions. Preliminary investigations into the accuracy of the UV-MFRSR calibrated with the Langley method are presented and successful column ozone retrievals are demonstrated with the UV-MFRSR under clear skies.
Abstract
Tropical cyclone (TC) outflow and its relationship to TC intensity change and structure were investigated in the Office of Naval Research Tropical Cyclone Intensity (TCI) field program during 2015 using dropsondes deployed from the innovative new High-Definition Sounding System (HDSS) and remotely sensed observations from the Hurricane Imaging Radiometer (HIRAD), both on board the NASA WB-57 that flew in the lower stratosphere. Three noteworthy hurricanes were intensively observed with unprecedented horizontal resolution: Joaquin in the Atlantic and Marty and Patricia in the eastern North Pacific. Nearly 800 dropsondes were deployed from the WB-57 flight level of ∼60,000 ft (∼18 km), recording atmospheric conditions from the lower stratosphere to the surface, while HIRAD measured the surface winds in a 50-km-wide swath with a horizontal resolution of 2 km. Dropsonde transects with 4–10-km spacing through the inner cores of Hurricanes Patricia, Joaquin, and Marty depict the large horizontal and vertical gradients in winds and thermodynamic properties. An innovative technique utilizing GPS positions of the HDSS reveals the vortex tilt in detail not possible before. In four TCI flights over Joaquin, systematic measurements of a major hurricane’s outflow layer were made at high spatial resolution for the first time. Dropsondes deployed at 4-km intervals as the WB-57 flew over the center of Hurricane Patricia reveal in unprecedented detail the inner-core structure and upper-tropospheric outflow associated with this historic hurricane. Analyses and numerical modeling studies are in progress to understand and predict the complex factors that influenced Joaquin’s and Patricia’s unusual intensity changes.
Abstract
Tropical cyclone (TC) outflow and its relationship to TC intensity change and structure were investigated in the Office of Naval Research Tropical Cyclone Intensity (TCI) field program during 2015 using dropsondes deployed from the innovative new High-Definition Sounding System (HDSS) and remotely sensed observations from the Hurricane Imaging Radiometer (HIRAD), both on board the NASA WB-57 that flew in the lower stratosphere. Three noteworthy hurricanes were intensively observed with unprecedented horizontal resolution: Joaquin in the Atlantic and Marty and Patricia in the eastern North Pacific. Nearly 800 dropsondes were deployed from the WB-57 flight level of ∼60,000 ft (∼18 km), recording atmospheric conditions from the lower stratosphere to the surface, while HIRAD measured the surface winds in a 50-km-wide swath with a horizontal resolution of 2 km. Dropsonde transects with 4–10-km spacing through the inner cores of Hurricanes Patricia, Joaquin, and Marty depict the large horizontal and vertical gradients in winds and thermodynamic properties. An innovative technique utilizing GPS positions of the HDSS reveals the vortex tilt in detail not possible before. In four TCI flights over Joaquin, systematic measurements of a major hurricane’s outflow layer were made at high spatial resolution for the first time. Dropsondes deployed at 4-km intervals as the WB-57 flew over the center of Hurricane Patricia reveal in unprecedented detail the inner-core structure and upper-tropospheric outflow associated with this historic hurricane. Analyses and numerical modeling studies are in progress to understand and predict the complex factors that influenced Joaquin’s and Patricia’s unusual intensity changes.
