174 Matching Results

Search Results

Advanced search parameters have been applied.

An Investigation of Aircraft Heaters 25: Use of the Thermopile Radiometer

Description: Report presenting an analysis of the thermopile radiometer as used in the measurement of irradiation and radiant power interchange is given. The theory of the instrument when used to measure irradiation and net radiant power interchange is developed, and the precautions to be observed when using it for these measurements are presented.
Date: April 1945
Creator: Boelter, L. M. K.; Bromberg, R.; Gier, J. T. & Dempster, E. R.
Partner: UNT Libraries Government Documents Department

Report on Broadband Solar Radiometer Inconsistencies at the Atmospheric Radiation (ARM) Southern Great Plains (SGP) Central Facility During the ARM Enhanced Shortwave Experiment (ARESE)

Description: Broadband solar radiometer data collected at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Central Facility during the ARM Enhanced Shortwave Experiment (ARESE) exhibits inconsistencies and inter-calibration offsets. This report examines these problems, and in some cases, suggests error sources and possible solutions. The data discussed here covers the period from September 28, 1995, through October 30, 1995.
Date: June 18, 1996
Creator: Long, CN
Partner: UNT Libraries Government Documents Department

Microwave Radiometer – 3 Channel (MWR3C) Handbook

Description: The microwave radiometer 3-channel (MWR3C) provides time-series measurements of brightness temperatures from three channels centered at 23.834, 30, and 89 GHz. These three channels are sensitive to the presence of liquid water and precipitable water vapor.
Date: May 4, 2012
Creator: Cadeddu, MP
Partner: UNT Libraries Government Documents Department

Tower Camera Handbook

Description: The tower camera in Barrow provides hourly images of ground surrounding the tower. These images may be used to determine fractional snow cover as winter arrives, for comparison with the albedo that can be calculated from downward-looking radiometers, as well as some indication of present weather. Similarly, during spring time, the camera images show the changes in the ground albedo as the snow melts. The tower images are saved in hourly intervals. In addition, two other cameras, the skydeck camera in Barrow and the piling camera in Atqasuk, show the current conditions at those sites.
Date: January 1, 2005
Creator: Moudry, D
Partner: UNT Libraries Government Documents Department

Microwave Radiometer (MWR) Handbook

Description: The Microwave Radiometer (MWR) provides time-series measurements of column-integrated amounts of water vapor and liquid water. The instrument itself is essentially a sensitive microwave receiver. That is, it is tuned to measure the microwave emissions of the vapor and liquid water molecules in the atmosphere at specific frequencies.
Date: August 1, 2006
Creator: Morris, VR
Partner: UNT Libraries Government Documents Department

Rotating Shadowband Spectroradiometer (RSS) Handbook

Description: The rotating shawdowband spectroradiometer (RSS) implements the same automated shadowbanding technique used by the multifilter rotating shadowband radiometer (MFRSR), and so it too provides spectrally-resolved, direct-normal, diffuse-horizontal, and total-horizontal irradiances, and can be calibrated in situ via Langley regression. The irradiance spectra are measured simultaneously at all spectral elements (pixels) in 360-nm to 1050-nm range.
Date: January 1, 2005
Creator: Kiedron, P.; Schlemmer, J. & Klassen, M.
Partner: UNT Libraries Government Documents Department

Multi-Filter Rotating Shadowband Radiometers Mentor Report and Baseline Surface Radiation Network Submission Status

Description: There are currently twenty-four Multi-Filter Rotating Shadowband Radiometers (MFRSR) operating within Atmospheric Radiation Measurement (ARM). Eighteen are located within the Southern Great Plains (SGP) region, there is one at each of the North Slope of Alaska (NSA) and Tropical Western Pacific (TWP) sites, and one is part of the instrumentation of the ARM Mobile Facility. At this time there are four sites, all extended facilities within the SGP, that are equipped for a MFRSR but do not have one due to instrument failure and a lack of spare instruments. In addition to the MFRSRs, there are three other MFRSR derived instruments that ARM operates. They are the Multi-Filter Radiometer (MFR), the Normal Incidence Multi-Filter Radiometer (NIMFR) and the Narrow Field of View (NFOV) radiometer. All are essentially just the head of a MFRSR used in innovative ways. The MFR is mounted on a tower and pointed at the surface. At the SGP Central Facility there is one at ten meters and one at twenty-five meters. The NSA has a MFR at each station, both at the ten meter level. ARM operates three NIMFRs; one is at the SGP Central Facility and one at each of the NSA stations. There are two NFOVs, both at the SGP Central Facility. One is a single channel (870) and the other utilizes two channels (673 and 870).
Date: March 18, 2005
Creator: Hodges, G.
Partner: UNT Libraries Government Documents Department

Atmospheric Radiation Measurement Program facilities newsletter, August 2003.

Description: This Monthly newsletter discusses the following topic: New Atmospheric Profiling Instrument Added to SGP CART Suite--A new atmospheric profiling instrument at the SGP CART site is giving researchers an additional useful data stream. The new instrument is a microwave radiometer profiler (MWRP) developed by Radiometrics Corporation.
Date: September 2, 2003
Creator: Holdridge, D.J.
Partner: UNT Libraries Government Documents Department

Changes to MFRSRCLDOD1MIN Datastream

Description: Significant updates were made to the multifilter rotating shadowband radiometer (MFRSR) cloud optical depth (MFRSRCLDOD) value-added product (VAP) in 2011. The original intent of the update was to add quality control (QC) flags and to update the VAP to use the improved retrievals of liquid water path (LWP) from the Microwave Radiometer Retrievals (MWRRET) VAP rather than the statistical retrievals of LWP from the Microwave Radiometer Line of Sight (MWRLOS) datastream. Although this was originally intended to be a straightforward update of the code, it became more complicated due to the following factors: (1) a new developer and translator team were working with the code; (2) numerous small changes had to be made to the code to consistently implement the QC flags; and (3) ARM standards have changed over the years since the code was originally developed.
Date: May 23, 2012
Creator: McFarlane, S. & Shi, Y.
Partner: UNT Libraries Government Documents Department

Cloud Optical Depths and Liquid Water Paths at the NSA CART

Description: Cloud optical depths have been measured using multifilter rotating shadowband radiometers (MFRSRs) at Barrow and Atqasuk, and liquid water paths have been measured at Barrow using a microwave radiometer (MWR) during the warm season (June-September) in 1999. Comparisons have been made between these quantities and the corresponding ones determined from the ECMWF GCM. Hour-by-hour comparisons of cloud optical depths show considerable scatter. The scatter is reduced, but is still substantial, when the averaging period is increased to ''daily'' averages, i.e., the time period each day over which the MFRSR can make measurements. This period varied between 18 hours in June and 6 hours in September. Preliminary results indicate that, for measured cloud optical depths less than approximately 25, the ECMWF has a low bias in its predictions, consistent with a low bias in predicted liquid water path. Based on a more limited set of data, the optical depths at Atqasuk were found to be generally lower than those at Barrow, a trend at least qualitatively captured by the ECMWF model. Analyses to identify the cause of the biases and the considerable scatter in the predictions are continuing.
Date: March 14, 2000
Creator: Doran, J. C.; Barnard, James C.; Zhong, Shiyuan & Jakob, C J.
Partner: UNT Libraries Government Documents Department

Multifilter Rotating Shadowband Radiometer (MFRSR) Handbook

Description: The visible Multifilter Rotating Shadowband Radiometer (MFRSR) is a passive instrument that measures global and diffuse components of solar irradiance at six narrowband channels and one open, or broadband, channel (Harrison et al. 1994). Direct irradiance is not a primary measurement, but is calculated using the diffuse and global measurements. To collect one data record, the MFRSR takes measurements at four different shadowband positions. The first measurement is taken with the shadowband in the nadir (home) position. The next three measurements are, in order, the first side-band, sun-blocked, and second side-band. The side-band measurements are used to correct for the portion of the sky obscured by the shadowband. The nominal wavelengths of the narrowband channels are 415, 500, 615, 673, 870, and 940 nm. From such measurements, one may infer the atmosphere's aerosol optical depth at each wavelength. In turn, these optical depths may be used to derive information about the column abundances of ozone and water vapor (Michalsky et al. 1995), as well as aerosol (Harrison and Michalsky 1994) and other atmospheric constituents.
Date: February 7, 2011
Creator: Hodges, GB & Michalsky, JJ
Partner: UNT Libraries Government Documents Department

MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Data Sets (Revision 2)

Description: This report provides a short description of the Atmospheric Radiation Measurement (ARM) Climate Research Facility microwave radiometer (MWR) Retrieval (MWRRET) value-added product (VAP) algorithm. This algorithm utilizes a complementary physical retrieval method and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).
Date: July 25, 2011
Creator: Gaustad, KL; Turner, DD & McFarlane, SA
Partner: UNT Libraries Government Documents Department

Narrow Field of View Zenith Radiometer (NFOV) Handbook

Description: The two-channel narrow field-of-view radiometer (NFOV2) is a ground-based radiometer that looks straight up and measures radiance directly above the instrument at wavelengths of 673 and 870 nm. The field-of-view of the instrument is 1.2 degrees, and the sampling time resolution is one second. Measurements of the NFOV2 have been used to retrieve optical properties for overhead clouds that range from patchy to overcast. With a one-second sampling rate of the NFOV2, faster than almost any other ARM Climate Research Facility (ACRF) instrument, we are able, for the first time, to capture changes in cloud optical properties at the natural time scale of cloud evolution.
Date: November 1, 2008
Creator: Chiu, C; Marshak, A; Hodges, G; Barnard, JC & Schmelzer, J
Partner: UNT Libraries Government Documents Department

Best Estimate Radiation Flux Value-Added Procedure: Algorithm Operational Details and Explanations

Description: This document describes some specifics of the algorithm for best estimate evaluation of radiation fluxes at Southern Great Plains (SGP) Central Facility (CF). It uses the data available from the three co-located surface radiometer platforms at the SGP CF to automatically determine the best estimate of the irradiance measurements available. The Best Estimate Flux (BEFlux) value-added procedure (VAP) was previously named Best Estimate ShortWave (BESW) VAP, which included all of the broadband and spectral shortwave (SW) measurements for the SGP CF. In BESW, multiple measurements of the same quantities were handled simply by designating one as the primary measurement and using all others to merely fill in any gaps. Thus, this “BESW” is better termed “most continuous,” since no additional quality assessment was applied. We modified the algorithm in BESW to use the average of the closest two measurements as the best estimate when possible, if these measurements pass all quality assessment criteria. Furthermore, we included longwave (LW) fields in the best estimate evaluation to include all major components of the surface radiative energy budget, and renamed the VAP to Best Estimate Flux (BEFLUX1LONG).
Date: October 1, 2002
Creator: Shi, Y. & Long, C. N.
Partner: UNT Libraries Government Documents Department

Cimel Sunphotometer (CSPHOT) Handbook

Description: The Cimel sunphotometer (CSPHOT) is a multi-channel, automatic sun-and-sky scanning radiometer that measures the direct solar irradiance and sky radiance at the Earth’s surface. Measurements are taken at pre-determined discrete wavelengths in the visible and near-IR parts of the spectrum to determine atmospheric transmission and scattering properties. This instrument is weather-proof and requires little maintenance during periods of adverse weather conditions. It takes measurements only during daylight hours (sun above horizon).
Date: January 17, 2011
Creator: Gregory, L
Partner: UNT Libraries Government Documents Department

ARM Climate Research Facility Spectral Surface Albedo Value-Added Product (VAP) Report

Description: This document describes the input requirements, output data products, and methodology for the Spectral Surface Albedo (SURFSPECALB) value-added product (VAP). The SURFSPECALB VAP produces a best-estimate near-continuous high spectral resolution albedo data product using measurements from multifilter radiometers (MFRs). The VAP first identifies best estimates for the MFR downwelling and upwelling shortwave irradiance values, and then calculates narrowband spectral albedo from these best-estimate irradiance values. The methodology for finding the best-estimate values is based on a simple process of screening suspect data and backfilling screened and missing data with estimated values when possible. The resulting best-estimate MFR narrowband spectral albedos are used to determine a daily surface type (snow, 100% vegetation, partial vegetation, or 0% vegetation). For non-snow surfaces, a piecewise continuous function is used to estimate a high spectral resolution albedo at 1 min temporal and 10 cm-1 spectral resolution.
Date: July 15, 2011
Creator: McFarlane, S; Gaustad, K; Long, C & Mlawer, E
Partner: UNT Libraries Government Documents Department

3 mm Anisotropy Measurement: On the Quadrupole Component in theCosmic Background Radiation

Description: We have mapped the large-scale anisotropy in the cosmic background radiation at 3 mm wavelength using a liquid-helium-cooled balloon-borne radiometer sensitive enough to detect the dipole in one gondola rotation (1 minute). Statistical errors on the dipole and quadrupole components are below 0.1 mK with less than 0.1 m K galactic contribution. We find a dipole consistent with previous measurements but disagree with recent quadrupole reports. The measurement is also useful in searching for spectral distortions.
Date: November 1, 1982
Creator: Lubin, Philip M.; Epstein, Gerald L. & Smoot, George F.
Partner: UNT Libraries Government Documents Department

Merged Sounding Value-Added Product

Description: The Merged Sounding value-added product (VAP) uses a combination of observations from radiosonde soundings, the microwave radiometer (MWR), surface meteorological instruments, and European Centre for Medium-Range Weather Forecasts (ECMWF) model output with a sophisticated scaling/interpolation/smoothing scheme in order to define profiles of the atmospheric thermodynamic state at one-minute temporal intervals and a total of 266 altitude levels.
Date: March 3, 2010
Creator: Troyan, D.
Partner: UNT Libraries Government Documents Department

A comparison of cloud microphysical quantities with forecasts from cloud prediction models

Description: Numerical weather prediction models (ECMWF, NCEP) are evaluated using ARM observational data collected at the Southern Great Plains (SGP) site. Cloud forecasts generated by the models are compared with cloud microphysical quantities, retrieved using a variety of parameterizations. Information gained from this comparison will be utilized during the FASTER project, as models are evaluated for their ability to reproduce fast physical processes detected in the observations. Here the model performance is quantified against the observations through a statistical analysis. Observations from remote sensing instruments (radar, lidar, radiometer and radiosonde) are used to derive the cloud microphysical quantities: ice water content, liquid water content, ice effective radius and liquid effective radius. Unfortunately, discrepancies in the derived quantities arise when different retrieval schemes are applied to the observations. The uncertainty inherent in retrieving the microphysical quantities using various retrievals is estimated from the range of output microphysical values. ARM microphysical retrieval schemes (Microbase, Mace) are examined along with the CloudNet retrieval processing of data from the ARM sites for this purpose. Through the interfacing of CloudNet and “ARM” processing schemes an ARMNET product is produced and employed as accepted observations in the assessment of cloud model predictions.
Date: March 15, 2010
Creator: Dunn, M.; Jensen, M.; Hogan, R.; O’Connor, E. & Huang, D.
Partner: UNT Libraries Government Documents Department

Low Frequency measurment of the Spectrum of the Cosmic BackgroundRadiation

Description: We have made measurements of the cosmic background radiation spectrum at 5 wavelengths (0.33, 0.9, 3, 6.3, and 12 cm) using radiometers with wavelength-scaled corrugated horn antennas having very low sidelobes. A single large-mouth (0.7 m diameter) liquid-helium-cooled absolute reference load was used for all five radiometers. The results of the observations are consistent with previous measurements and represent a significant improvement in accuracy.
Date: June 1, 1983
Creator: Smoot, G.F.; De Amici, G.; Friedman, S.D.; Witebsky, C.; Mandolesi, N.; Partridge, R.b. et al.
Partner: UNT Libraries Government Documents Department

New 33 GHz Measurements of the Cosmic Background RadiationIntensity

Description: New measurements have been made of the intensity of the cosmic background radiation (CBR) at 33 GHz (0.91 cm). The experiment was part of a larger effort to measure the spectrum of the CBR between 2.5 and 90 GHz (12 and 0.33 cm). Details are given of the experimental equipment and measurement procedures. The results of measurements made in 1982 and 1983 are presented and discussed in relation to preliminary results from the other radiometers. The measured value, T{sub CBR} = (2.81 {+-} 0.12) K, is in very good agreement both with those previously published and those reported by our collaborators.
Date: March 1, 1985
Creator: De Amici, G.; Smoot, G.; Friedman, S.G. & Witebsky, C.
Partner: UNT Libraries Government Documents Department

MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Datasets May 2009

Description: This report provides a short description of the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) microwave radiometer (MWR) RETrievel (MWRRET) value-added product (VAP) algorithm. This algorithm utilizes a complementary physical retrieval method and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).
Date: May 30, 2009
Creator: Gaustad, KL & Turner, DD
Partner: UNT Libraries Government Documents Department