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David D Turner - One of the best experts on this subject based on the ideXlab platform.
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characteristic atmospheric radiative heating rate profiles in arctic clouds as observed at barrow alaska
Journal of Applied Meteorology and Climatology, 2018Co-Authors: David D Turner, Matthew D Shupe, A B ZwinkAbstract:AbstractA 2-yr cloud microphysical property dataset derived from ground-based remote sensors at the Atmospheric Radiation Measurement site near Barrow, Alaska, was used as input into a radiative tr...
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the atmospheric Radiation Measurement arm program network of microwave radiometers instrumentation data and retrievals
Atmospheric Measurement Techniques, 2013Co-Authors: M P Cadeddu, J C Liljegren, David D TurnerAbstract:Abstract. The Climate Research Facility of the US Department of Energy's Atmospheric Radiation Measurement (ARM) Program operates a network of ground-based microwave radiometers. Data and retrievals from these instruments have been available to the scientific community for almost 20 yr. In the past five years the network has expanded to include a total of 22 microwave radiometers deployed in various locations around the world. The new instruments cover a frequency range between 22 and 197 GHz and are consistently and automatically calibrated. The latest addition to the network is a new generation of three-channel radiometers, currently in the early stage of deployment at all ARM sites. The network has been specifically designed to achieve increased accuracy in the retrieval of precipitable water vapor (PWV) and cloud liquid water path (LWP) with the long-term goal of providing the scientific community with reliable, calibrated radiometric data and retrievals of important geophysical quantities with well-characterized uncertainties. The radiometers provide high-quality, continuous datasets that can be utilized in a wealth of applications and scientific studies. This paper presents an overview of the microwave instrumentation, calibration procedures, data, and retrievals that are available for download from the ARM data archive.
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full time eye safe cloud and aerosol lidar observation at atmospheric Radiation Measurement program sites instruments and data analysis
2013Co-Authors: James R Campbell, David D Turner, Connor J Flynn, Dennis L Hlavka, Ellsworth J Welton, James D Spinhirne, Stanley V Scott, I H HwangAbstract:Atmospheric radiative forcing, surface Radiation budget, and top-of-the-atmosphere radiance interpretation involve knowledge of the vertical height structure of overlying cloud and aerosol layers. During the last decade, the U.S. Department of Energy, through the Atmospheric Radiation Measurement (ARM) program, has constructed four long-term atmospheric observing sites in strategic climate regimes (north-central Oklahoma; Barrow, Alaska; and Nauru and Manus Islands in the tropical western Pacific). Micropulse lidar (MPL) systems provide continuous, autonomous observation of nearly all significant atmospheric clouds and aerosols at each of the central ARM facilities. These systems are compact, and transmitted pulses are eye safe. Eye safety is achieved by expanding relatively low-powered outgoing pulse energy through a shared, coaxial transmit/receive telescope. ARM MPL system specifications and specific unit optical designs are discussed. Data normalization and calibration techniques are presented. These techniques, in tandem, represent an operational value-added processing package used to produce normalized data products for ARM cloud and aerosol research.
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full time eye safe cloud and aerosol lidar observation at atmospheric Radiation Measurement program sites instruments and data analysis
2013Co-Authors: James R Campbell, David D Turner, Connor J Flynn, Dennis L Hlavka, Ellsworth J Welton, James D Spinhirne, Stanley V Scott, I H HwangAbstract:Atmospheric radiative forcing, surface Radiation budget, and top of the atmosphere radiance interpretation involves a knowledge of the vertical height structure of overlying cloud and aerosol layers. During the last decade, the U.S. Department of Energy through I the Atmospheric Radiation Measurement (ARM) program has constructed four long- term atmospheric observing sites in strategic climate regimes (north central Oklahoma, In Barrow. Alaska, and Nauru and Manus Islands in the tropical western Pacific). Micro Pulse Lidar (MPL) systems provide continuous, autonomous observation of all significant atmospheric cloud and aerosol at each of the central ARM facilities. Systems are compact and transmitted pulses are eye-safe. Eye-safety is achieved by expanding relatively low-powered outgoing Pulse energy through a shared, coaxial transmit/receive telescope. ARM NIPL system specifications, and specific unit optical designs are discussed. Data normalization and calibration techniques are presented. A multiple cloud boundary detection algorithm is also described. These techniques in tandem represent an operational value added processing package used to produce normalized data products for Cloud and aerosol research and the historical ARM data archive.
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validation of aerosol extinction and water vapor profiles from routine atmospheric Radiation Measurement program climate research facility Measurements
Journal of Geophysical Research, 2009Co-Authors: B Schmid, David D Turner, Connor J Flynn, Rob K Newsom, R A Ferrare, Marian Clayton, E Andrews, J A Ogren, R Johnson, Philip B RussellAbstract:[1] The accuracy with which vertical profiles of aerosol extinction σep(λ) can be measured using routine Atmospheric Radiation Measurement Program (ARM) Climate Research Facility (ACRF) Measurements and was assessed using data from two airborne field campaigns, the ARM Aerosol Intensive Operation Period (AIOP, May 2003), and the Aerosol Lidar Validation Experiment (ALIVE, September 2005). This assessment pertains to the aerosol at its ambient concentration and thermodynamic state (i.e., σep(λ) either free of or corrected for sampling artifacts) and includes the following ACRF routine methods: Raman lidar, micropulse lidar (MPL), and in situ aerosol profiles (IAP) with a small aircraft. Profiles of aerosol optical depth τp(λ), from which the profiles of σep(λ) are derived through vertical differentiation, were measured by the NASA Ames Airborne Tracking 14-channel Sun photometer (AATS-14); these data were used as benchmark in this evaluation. The ACRF IAP σep(550 nm) were lower by 11% (during AIOP) and higher by 1% (during ALIVE) when compared to AATS-14. The ACRF MPL σep(523 nm) Measurements were higher by 24% (AIOP) and 19–21% (ALIVE) compared to AATS-14, but the correlation improved significantly during ALIVE. In the AIOP, a second MPL operated by NASA showed a smaller positive bias (13%) with respect to AATS-14. The ACRF Raman lidar σep(355 nm) Measurements were larger by 54% (AIOP) and by 6% (ALIVE) compared to AATS-14. The large bias in the Raman lidar Measurements during AIOP stemmed from a gradual loss of Raman lidar sensitivity starting about the end of 2001 going unnoticed until after AIOP. A major refurbishment and upgrade of the instrument and improvements to a data processing algorithm led to the significant improvement and very small bias in ALIVE. Finally, we find that during ALIVE the Raman lidar water vapor densities ρw are 8% larger when compared to AATS-14, whereas in situ measured ρw aboard two different aircraft are smaller than the AATS-14 values by 0.3–3%.
Gerald M Stokes - One of the best experts on this subject based on the ideXlab platform.
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the atmospheric Radiation Measurement program
Physics Today, 2003Co-Authors: Thomas P Ackerman, Gerald M StokesAbstract:To predict reliably what increased greenhouse gases will do to global climate, we have to understand the crucial role of clouds.
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the atmospheric Radiation Measurement arm program programmatic background and design of the cloud and Radiation test bed
Bulletin of the American Meteorological Society, 1994Co-Authors: Gerald M Stokes, Stephen E. SchwartzAbstract:Abstract The Atmospheric Radiation Measurement (ARM) Program, supported by the U.S. Department of Energy, is a major new program of atmospheric Measurement and modeling. The program is intended to improve the understanding of processes that affect atmospheric Radiation and the description of these processes in climate models. An accurate description of atmospheric Radiation and its interaction with clouds and cloud processes is necessary to improve the performance of and confidence in models used to study and predict climate change. The ARM Program will employ five (this paper was prepared prior to a decision to limit the number of primary Measurement sites to three) highly instrumented primary Measurement sites for up to 10 years at land and ocean locations, from the Tropics to the Arctic, and will conduct observations for shorter periods at additional sites and in specialized campaigns. Quantities to be measured at these sites include longwave and shortwave Radiation, the spatial and temporal distributi...
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The Atmospheric Radiation Measurement (ARM) Program: Programmatic Background and Design of the Cloud and Radiation Test Bed
Bulletin of the American Meteorological Society, 1994Co-Authors: Gerald M Stokes, Stephen E. SchwartzAbstract:Abstract The Atmospheric Radiation Measurement (ARM) Program, supported by the U.S. Department of Energy, is a major new program of atmospheric Measurement and modeling. The program is intended to improve the understanding of processes that affect atmospheric Radiation and the description of these processes in climate models. An accurate description of atmospheric Radiation and its interaction with clouds and cloud processes is necessary to improve the performance of and confidence in models used to study and predict climate change. The ARM Program will employ five (this paper was prepared prior to a decision to limit the number of primary Measurement sites to three) highly instrumented primary Measurement sites for up to 10 years at land and ocean locations, from the Tropics to the Arctic, and will conduct observations for shorter periods at additional sites and in specialized campaigns. Quantities to be measured at these sites include longwave and shortwave Radiation, the spatial and temporal distributi...
Gerald G Mace - One of the best experts on this subject based on the ideXlab platform.
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importance of small ice crystals to cirrus properties observations from the tropical warm pool international cloud experiment twp ice
Geophysical Research Letters, 2007Co-Authors: Greg M Mcfarquhar, Matt Freer, D Baumgardner, Gregory L Kok, Gerald G MaceAbstract:[1] During the Department of Energy Atmospheric Radiation Measurement Program (DOE ARM) sponsored Tropical Warm Pool International Cloud Experiment (TWP-ICE), ice crystals with maximum dimensions (D) 100 μm measured by the Cloud Imaging Probe, suggesting that ice crystals may have been shattering or bouncing on the CAS inlet or protruding airflow shroud enhancing N>3−50,CAS. During the Costa Rica Aura Validation Experiment N3−50,CAS measured by a CAS without an airflow shroud were an order of magnitude less than those observed during TWP-ICE. This, and estimates of the maximum shattering based on the inlet and shroud sizes, suggest that the airflow shroud used during TWP-ICE was responsible for much of the shattering or bouncing.
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cloud radiative forcing at the atmospheric Radiation Measurement program climate research facility 2 vertical redistribution of radiant energy by clouds
Journal of Geophysical Research, 2006Co-Authors: Gerald G Mace, Sally Benson, Seiji KatoAbstract:Documentation of the effects of clouds on the radiant energy balance of the surface and atmosphere represents a shortcoming in the set of observations that are needed to ascertain the validity of climate model simulations. While clouds are known to cool the climate system from top of atmosphere (TOA) Radiation budget studies, the redistribution of energy between the surface and atmosphere and within the atmosphere by clouds has not been examined in detail with observations. Using data collected at the Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) site, we use Measurements of cloud occurrence and structure together with a scheme to characterize the cloud microphysical and radiative properties to estimate the uncertainty in our ability to calculate the radiative forcing and effect of clouds at the top of atmosphere, the surface and within the atmosphere. We find that overcast clouds during 2000 tended to have a small net influence on the atmosphere (6 W m -2 ± 3 W m -2 of heating) with net TOA and surface cooling (25 W m -2 ± 3 W m -2 and 32 ± 3 W m -2 , respectively). These statistics mask a significant redistribution of radiant energy within the atmosphere by clouds where low overcast clouds resulted in strong atmospheric cooling (37 W m -2 ± 9 W m -2 ), and thin high clouds resulted in warming (21 W m -2 ± 6 W m -2 ) suggesting that accurate prediction of the phasing of these cloud types within meteorological features is important for capturing the essential feedbacks by clouds to the general circulation.
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cloud radiative forcing at the atmospheric Radiation Measurement program climate research facility 1 technique validation and comparison to satellite derived diagnostic quantities
Journal of Geophysical Research, 2006Co-Authors: Gerald G Mace, Cynthia H. Twohy, Sally Benson, Seiji Kato, Patrick Minnis, Xiquan Dong, Karen L Sonntag, Michael R Poellot, Charles N. LongAbstract:[1] It has been hypothesized that continuous ground-based remote sensing Measurements from collocated active and passive remote sensors combined with regular soundings of the atmospheric thermodynamic structure can be combined to describe the effects of clouds on the clear sky Radiation fluxes. We critically test that hypothesis in this paper and a companion paper (part 2). Using data collected at the Southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site sponsored by the U.S. Department of Energy, we explore an analysis methodology that results in the characterization of the physical state of the atmospheric profile at time resolutions of 5 min and vertical resolutions of 90 m. The description includes thermodynamics and water vapor profile information derived by merging radiosonde soundings with ground-based data and continues through specification of the cloud layer occurrence and microphysical and radiative properties derived from retrieval algorithms and parameterizations. The description of the atmospheric physical state includes a calculation of the clear and cloudy sky solar and infrared flux profiles. Validation of the methodology is provided by comparing the calculated fluxes with top of atmosphere (TOA) and surface flux Measurements and by comparing the total column optical depths to independently derived estimates. We find over a 1-year period of comparison in overcast uniform skies that the calculations are strongly correlated to Measurements with biases in the flux quantities at the surface and TOA of less than 6% and median fractional errors ranging from 12% to as low as 2%. In the optical depth comparison for uniform overcast skies during the year 2000 where the optical depth varies over more than 3 orders of magnitude we find a mean positive bias of less than 1% and a 0.6 correlation coefficient. In addition to a case study where we examine the cloud radiative effects at the TOA, surface and atmosphere by a middle latitude cyclone, we examine the cloud top pressure and optical depth retrievals of ISCCP and LBTM over a period of 1 year. Using overcast periods from the year 2000, we find that the satellite algorithms tend to compare well with data overall but there is a tendency to bias cloud tops into the middle troposphere and underestimate optical depth in high optical depth events.
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a 25 month database of stratus cloud properties generated from ground based Measurements at the atmospheric Radiation Measurement southern great plains site
Journal of Geophysical Research, 2000Co-Authors: Xiquan Dong, Charles N. Long, Gerald G Mace, Thomas P Ackerman, Eugene E Clothiaux, Patrick Minnis, J C LiljegrenAbstract:A 25-month database of the macrophysical, microphysical, and radiative properties of isolated and overcast low-level stratus clouds has been generated using a newly developed parameterization and surface Measurements from the Atmospheric Radiation Measurement central facility in Oklahoma. The database (5-min resolution) includes two parts: Measurements and retrievals. The former consist of cloud base and top heights, layer-mean temperature, cloud liquid water path, and solar transmission ratio measured by a ground-based lidar/ceilometer and radar pair, radiosondes, a microwave radiometer, and a standard Eppley precision spectral pyranometer, respectively. The retrievals include the cloud-droplet effective radius and number concentration and broadband shortwave optical depth and cloud and top-of-atmosphere albedos. Stratus without any overlying mid or high-level clouds occurred most frequently during winter and least often during summer. Mean cloud-layer altitudes and geometric thicknesses were higher and greater, respectively, in summer than in winter. Both quantities are positively correlated with the cloud-layer mean temperature. Mean cloud-droplet effective radii range from 8.1 μm in winter to 9.7 μm during summer, while cloud-droplet number concentrations during winter are nearly twice those in summer. Since cloud liquid water paths are almost the same in both seasons, cloud optical depth is higher during the winter, leading to greater cloud albedos and lower cloud transmittances.
Thomas P Ackerman - One of the best experts on this subject based on the ideXlab platform.
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surface shortwave aerosol radiative forcing during the atmospheric Radiation Measurement mobile facility deployment in niamey niger
Journal of Geophysical Research, 2009Co-Authors: Sally A Mcfarlane, Evgueni I Kassianov, Connor J Flynn, James C. Barnard, Thomas P AckermanAbstract:[1] The Atmospheric Radiation Measurement (ARM) Program's Mobile Facility (AMF) was deployed to Niamey, Niger, during 2006. Niamey, which is located in sub-Saharan Africa, is affected by both dust and biomass burning emissions. Column aerosol optical properties were derived from multifilter rotating shadowband radiometer, Measurements and the vertical distribution of aerosol extinction was derived from a micropulse lidar during the two observed dry seasons (January–April and October–December). Mean aerosol optical depth (AOD) and single scattering albedo (SSA) at 500 nm during January–April were 0.53 ± 0.4 and 0.94 ± 0.05, while during October–December mean AOD and SSA were 0.33 ± 0.25 and 0.99 ± 0.01. Aerosol extinction profiles peaked near 500 m during the January–April period and near 100 m during the October–December period. Broadband shortwave surface fluxes and heating rate profiles were calculated using retrieved aerosol properties. Comparisons for noncloudy periods indicated that the remote sensing retrievals provided a reasonable estimation of the aerosol optical properties, with mean differences between calculated and observed fluxes of less than 5 W m−2 and RMS differences less than 25 W m−2. Sensitivity tests showed that the observed fluxes could be matched with variations of <10% in the inputs to the radiative transfer model. The calculated 24-h averaged SW instantaneous surface aerosol radiative forcing (ARF) was −21.1 ± 14.3 W m−2 and was estimated to account for 80% of the total radiative forcing at the surface. The ARF was larger during January–April (−28.5 ± 13.5 W m−2) than October–December (−11.9 ± 8.9 W m−2).
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the atmospheric Radiation Measurement program
Physics Today, 2003Co-Authors: Thomas P Ackerman, Gerald M StokesAbstract:To predict reliably what increased greenhouse gases will do to global climate, we have to understand the crucial role of clouds.
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a 25 month database of stratus cloud properties generated from ground based Measurements at the atmospheric Radiation Measurement southern great plains site
Journal of Geophysical Research, 2000Co-Authors: Xiquan Dong, Charles N. Long, Gerald G Mace, Thomas P Ackerman, Eugene E Clothiaux, Patrick Minnis, J C LiljegrenAbstract:A 25-month database of the macrophysical, microphysical, and radiative properties of isolated and overcast low-level stratus clouds has been generated using a newly developed parameterization and surface Measurements from the Atmospheric Radiation Measurement central facility in Oklahoma. The database (5-min resolution) includes two parts: Measurements and retrievals. The former consist of cloud base and top heights, layer-mean temperature, cloud liquid water path, and solar transmission ratio measured by a ground-based lidar/ceilometer and radar pair, radiosondes, a microwave radiometer, and a standard Eppley precision spectral pyranometer, respectively. The retrievals include the cloud-droplet effective radius and number concentration and broadband shortwave optical depth and cloud and top-of-atmosphere albedos. Stratus without any overlying mid or high-level clouds occurred most frequently during winter and least often during summer. Mean cloud-layer altitudes and geometric thicknesses were higher and greater, respectively, in summer than in winter. Both quantities are positively correlated with the cloud-layer mean temperature. Mean cloud-droplet effective radii range from 8.1 μm in winter to 9.7 μm during summer, while cloud-droplet number concentrations during winter are nearly twice those in summer. Since cloud liquid water paths are almost the same in both seasons, cloud optical depth is higher during the winter, leading to greater cloud albedos and lower cloud transmittances.
Stephen E. Schwartz - One of the best experts on this subject based on the ideXlab platform.
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the atmospheric Radiation Measurement arm program programmatic background and design of the cloud and Radiation test bed
Bulletin of the American Meteorological Society, 1994Co-Authors: Gerald M Stokes, Stephen E. SchwartzAbstract:Abstract The Atmospheric Radiation Measurement (ARM) Program, supported by the U.S. Department of Energy, is a major new program of atmospheric Measurement and modeling. The program is intended to improve the understanding of processes that affect atmospheric Radiation and the description of these processes in climate models. An accurate description of atmospheric Radiation and its interaction with clouds and cloud processes is necessary to improve the performance of and confidence in models used to study and predict climate change. The ARM Program will employ five (this paper was prepared prior to a decision to limit the number of primary Measurement sites to three) highly instrumented primary Measurement sites for up to 10 years at land and ocean locations, from the Tropics to the Arctic, and will conduct observations for shorter periods at additional sites and in specialized campaigns. Quantities to be measured at these sites include longwave and shortwave Radiation, the spatial and temporal distributi...
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The Atmospheric Radiation Measurement (ARM) Program: Programmatic Background and Design of the Cloud and Radiation Test Bed
Bulletin of the American Meteorological Society, 1994Co-Authors: Gerald M Stokes, Stephen E. SchwartzAbstract:Abstract The Atmospheric Radiation Measurement (ARM) Program, supported by the U.S. Department of Energy, is a major new program of atmospheric Measurement and modeling. The program is intended to improve the understanding of processes that affect atmospheric Radiation and the description of these processes in climate models. An accurate description of atmospheric Radiation and its interaction with clouds and cloud processes is necessary to improve the performance of and confidence in models used to study and predict climate change. The ARM Program will employ five (this paper was prepared prior to a decision to limit the number of primary Measurement sites to three) highly instrumented primary Measurement sites for up to 10 years at land and ocean locations, from the Tropics to the Arctic, and will conduct observations for shorter periods at additional sites and in specialized campaigns. Quantities to be measured at these sites include longwave and shortwave Radiation, the spatial and temporal distributi...
