Radiative Heating in Ice

1977 ◽  
Vol 99 (2) ◽  
pp. 227-232 ◽  
Author(s):  
R. R. Gilpin ◽  
R. B. Robertson ◽  
B. Singh
Keyword(s):  
Theoretical Model ◽  
Spectral Dependence ◽  
Radiant Energy ◽  
Incident Radiation ◽  
Anisotropic Scattering ◽  
Radiative Heating ◽  
Energy Sources ◽  
Laboratory Measurements ◽  
Radiation Beam ◽  
Collimated Beam

The energy fluxes that exist in an ice sheet exposed to a collimated beam of radiant energy were examined. A theoretical model was used which includes the effects of anisotropic scattering as well as the spectral dependence of the absorption coefficient of ice and of the incident radiation beam. Laboratory measurements were also made which generally confirm the predictions of the model. The results calculated from the model are primarily intended for use in analyzing two particular problems involving radiative transfer in ice. These are: (a) the assessment of the feasibility of using radiant energy sources as a means of removing ice from structures, and (b) the prediction of temperatures and internal melting in ice covers on lakes and rivers due to the absorption of solar radiation.

Firefighter Safety Zones: A Theoretical Model Based on Radiative Heating

1998 ◽  
Vol 8 (2) ◽  
pp. 73 ◽  
Author(s):  
BW Butler ◽  
JD Cohen
Keyword(s):  
Theoretical Model ◽  
Radiant Energy ◽  
General Rule ◽  
Quantitative Information ◽  
Radiative Heating ◽  
Flame Height ◽  
Safety Zone ◽  
Model Predictions ◽  
Zone Radius ◽  
Height Model

Quantitative information regarding safety zone size for wildland firefighters is limited. We present a 3-surface theoretical model that describes the net radiant energy transfer to a firefighter standing a specified distance from a fire of specified height. Model predictions compare favorably with qualitative data from entrapments on four wildfires and two previously published models. Calculations indicate that for most fires, safety zones must be greater than 20 m wide to ensure firefighter survival. A general rule-of-thumb derived from this work is that a safety zone radius must be equal to or greater than 4 times the maximum flame height.

scholarly journals A Theoretical Model of Radiative Transfer in Young Sea Ice

1982 ◽  
Vol 28 (99) ◽  
pp. 341-356
Author(s):  
Donald K. Perovich ◽  
Thomas C. Grenfell
Keyword(s):  
Theoretical Model ◽  
Radiative Transfer ◽  
Phase Function ◽  
Incident Radiation ◽  
Single Scattering ◽  
Anisotropic Scattering ◽  
Discrete Ordinates ◽  
Ice Thickness ◽  
Surface Layers ◽  
Beam Incident

AbstractA four stream discrete-ordinates photometric model including both anisotropic scattering and refraction at the boundaries is presented which treats the case of a floating ice slab. The effects of refraction and reflection on the redistribution of the incident radiation field as it enters the ice are examined in detail. Using one- and two-layer models, theoretical albedos and transmittances are compared to values measured in the laboratory for thin salt ice. With an experimentally determined three-parameter Henyey–Greenstein phase function, comparisons at 650 nm yield single-scattering albedos ranging from 0.95 to 0.9997. The models are then used to compare the effects of diffuse and direct-beam incident radiation, to investigate the dependence of spectral albedo and transmittance on ice thickness, and to determine the influence of very cold and melted surface layers.

scholarly journals A Theoretical Model of Radiative Transfer in Young Sea Ice

1982 ◽  
Vol 28 (99) ◽  
pp. 341-356 ◽  
Author(s):  
Donald K. Perovich ◽  
Thomas C. Grenfell
Keyword(s):  
Theoretical Model ◽  
Radiative Transfer ◽  
Phase Function ◽  
Incident Radiation ◽  
Single Scattering ◽  
Anisotropic Scattering ◽  
Discrete Ordinates ◽  
Ice Thickness ◽  
Surface Layers ◽  
Beam Incident

AbstractA four stream discrete-ordinates photometric model including both anisotropic scattering and refraction at the boundaries is presented which treats the case of a floating ice slab. The effects of refraction and reflection on the redistribution of the incident radiation field as it enters the ice are examined in detail. Using one- and two-layer models, theoretical albedos and transmittances are compared to values measured in the laboratory for thin salt ice. With an experimentally determined three-parameter Henyey–Greenstein phase function, comparisons at 650 nm yield single-scattering albedos ranging from 0.95 to 0.9997. The models are then used to compare the effects of diffuse and direct-beam incident radiation, to investigate the dependence of spectral albedo and transmittance on ice thickness, and to determine the influence of very cold and melted surface layers.

Radiation-Induced Buoyancy-Driven Flow in Rectangular Enclosures: Experiment and Analysis

1987 ◽  
Vol 109 (2) ◽  
pp. 427-433 ◽  
Author(s):  
B. W. Webb ◽  
R. Viskanta
Keyword(s):  
Experimental Data ◽  
Temperature Field ◽  
Theoretical Model ◽  
Radiation Flux ◽  
Convective Motion ◽  
Radiative Heating ◽  
Working Fluid ◽  
Injection Technique ◽  
Flux Divergence ◽  
Radiation Induced

Experiments have been performed to study the rate of internal radiative heating on the natural convective motion in a vertical rectangular enclosure irradiated from the side. A Mach–Zehnder interferometer has been used to determine the temperature field, and a fluorescing dye injection technique was employed to illustrate the flow structure with water as the working fluid. A theoretical model is developed for predicting the absorption of thermal radiation and the subsequent buoyancy-driven flow. Predictions based on spectral calculations for the radiation flux divergence agree well with the experimental data.

Back-Melting of a Horizontal Cloudy Ice Layer with Radiative Heating

1979 ◽  
Vol 101 (1) ◽  
pp. 90-95 ◽  
Author(s):  
N. Seki ◽  
M. Sugawara ◽  
S. Fukusako
Keyword(s):  
Radiant Energy ◽  
Short Wave ◽  
Melting Rate ◽  
Radiative Heating ◽  
Wave Radiation ◽  
Band Model ◽  
Air Bubbles ◽  
Short Wave Radiation ◽  
Radiation Sources ◽  
Infrared Spectral

This paper is concerned with the melting of a horizontal ice layer sticking to a substrate by using halogen lamps, which are comparatively short wave radiation sources. This radiation in the visible and infrared spectral range may be employed to remove ice from structures subject to atmospheric icing. It is concluded that the behavior of radiation transfer in a cloudy ice layer depends a great deal on the density of the cloudy ice including air bubbles which produce the scattering of radiation. Also the phenomenon of back-melting caused by radiant energy penetrating through the ice layer is observed. Moreover, it is shown that the melting rate of an ice layer can be predicted numerically by using the band model of extinction coefficient for cloudy ice assumed in this study.

scholarly journals Direct Radiative Effect by Multicomponent Aerosol over China*

2015 ◽  
Vol 28 (9) ◽  
pp. 3472-3495 ◽  
Author(s):  
Xin Huang ◽  
Yu Song ◽  
Chun Zhao ◽  
Xuhui Cai ◽  
Hongsheng Zhang ◽  
...  
Keyword(s):  
Land Surface ◽  
Radiation Flux ◽  
Seasonal Pattern ◽  
Model Performance ◽  
Wrf Model ◽  
Incident Radiation ◽  
Heterogeneous Reactions ◽  
Radiative Heating ◽  
Radiative Effect ◽  
Hygroscopic Growth

Abstract The direct radiative effect (DRE) of multiple aerosol species [sulfate, nitrate, ammonium, black carbon (BC), organic carbon (OC), and mineral aerosol] and their spatiotemporal variations over China were investigated using a fully coupled meteorology–chemistry model [Weather Research and Forecasting (WRF) Model coupled with Chemistry (WRF-Chem)] for the entire year of 2006. This study made modifications to improve the model performance, including updating land surface parameters, improving the calculation of transition-metal-catalyzed oxidation of SO2, and adding heterogeneous reactions between mineral dust aerosol and acid gases. The modified model generally reproduced the magnitude, seasonal pattern, and spatial distribution of the measured meteorological conditions, concentrations of PM10 and its components, and aerosol optical depth (AOD), although some low biases existed in modeled aerosol concentrations. A diagnostic iteration method was used to estimate the overall DRE of aerosols and contributions from different components. At the land surface, the incident net radiation flux was reduced by 10.2 W m−2 over China. Aerosols significantly warmed the atmosphere with the national mean DRE of +10.8 W m−2. BC was the leading radiative heating component (+8.7 W m−2), followed by mineral aerosol (+1.1 W m−2). At the top of the atmosphere (TOA), BC introduced the largest radiative perturbation (+4.5 W m−2), followed by sulfate (−1.4 W m−2). The overall perturbation of aerosols on radiation transfer is quite small over China, demonstrating the counterbalancing effect between scattering and adsorbing aerosols. Aerosol DRE at the TOA had distinct seasonality, generally with a summer maximum and winter minimum, mainly determined by mass loadings, hygroscopic growth, and incident radiation flux.

Measurement and Application of Radiant Energy

2012 ◽  
Vol 503-504 ◽  
pp. 1463-1467
Author(s):  
Lin Wang ◽  
Hong Wang
Keyword(s):  
Radiant Energy ◽  
Incident Radiation ◽  
Energy Detector ◽  
Fundamental Knowledge ◽  
Thermal Detectors ◽  
Physical Quantities

Based on the application of radiant energy in various fields, the fundamental knowledge about incident radiation, including physical quantities and units, is summarized. Then, the category and principle of radiant energy detector are introduced, i.e. thermal detectors and photodetectors. Also, their application conditions are compared. It is significantly important for users to understand their operation principles and to choose an appropriate radiation measuring detector.

Improved Treatment of Anisotropic Scattering for Ultrafast Radiative Transfer Analysis

2013 ◽  
Author(s):  
Brian Hunter ◽  
Zhixiong Guo
Keyword(s):  
Radiative Transfer ◽  
Phase Function ◽  
Energy Deposition ◽  
Radiant Energy ◽  
Diffuse Radiation ◽  
Anisotropic Scattering ◽  
Heat Fluxes ◽  
Asymmetry Factor ◽  
Conservation Of Energy ◽  
Numerical Predictions

The necessity of conserving both scattered energy and asymmetry factor for ballistic incidence after either FVM or DOM discretization is convincingly shown by analyzing ultrafast laser radiative transfer in a cubic enclosure housing a participating medium. A phase-function normalization technique introduced previously by the present authors to correct for non-conservation of energy and asymmetry factor in diffuse radiant energy scattering is applied to scattering of ballistic incidence for the first time in 3-D FVM/DOM in order to improve treatment of anisotropic scattering through reduction of angular false scattering errors. Treatment of only the diffuse radiation will not conserve ballistic properties if the direction of ballistic incidence differs from a predetermined discrete direction. Our ultrafast radiative transfer predictions generated using the FVM and DOM are compared to benchmark Monte Carlo predictions in the literature to gauge accuracy and to illustrate the necessity of ballistic phase-function normalization. Additionally, numerical predictions of energy deposition in a tissue-phantom medium are analyzed to further clarify the importance of accurate numerical predictions. It is shown that the addition of proper ballistic phase-function treatment greatly improves predicted heat fluxes and energy deposition for anisotropic scattering and for situations where accurate numerical modeling is crucial.

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