Absolute radiometry technique for VUV and SXR radiation fluxes

1991 ◽  
pp. 161-162
Author(s):  
S. V. Bobashev ◽  
N. N. Salashchenko ◽  
L. A. Shmaenok
Keyword(s):  
Absolute Radiometry ◽  
Radiation Fluxes

Absolute radiometry technique for VUV and SXR radiation fluxes

1991 ◽  
Vol 21 (S1) ◽  
pp. S161-S162 ◽  
Author(s):  
S. V. Bobashev ◽  
N. N. Salashchenko ◽  
L. A. Shmaenok
Keyword(s):  
Absolute Radiometry ◽  
Radiation Fluxes

Characterizing the convective heat exchange with plastic shading nets under natural arid conditions

2019 ◽  
pp. 11-20
Author(s):  
Ahmed M Abdel-Ghanya ◽  
Ibrahim M Al-Helal
Keyword(s):  
Wind Speed ◽  
Thermal Radiation ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Convective Heat Exchange ◽  
Radiative Properties ◽  
Wooden Frame ◽  
Arid Conditions ◽  
Air Temperatures ◽  
Radiation Fluxes

Plastic nets are extensively used for shading purposes in arid regions such as in the Arabian Peninsula. Quantifying the convection exchange with shading net and understanding the mechanisms (free, mixed and forced) of convection are essential for analyzing energy exchange with shading nets. Unlike solar and thermal radiation, the convective energy, convective heat transfer coefficient and the nature of convection have never been theoretically estimated or experimentally measured for plastic nets under arid conditions. In this study, the convected heat exchanges with different plastic nets were quantified based on an energy balance applied to the nets under outdoor natural conditions. Therefore, each net was tacked onto a wooden frame, fixed horizontally at 1.5-m height over the floor. The downward and upward solar and thermal radiation fluxes were measured below and above each net on sunny days; also the wind speed over the net, and the net and air temperatures were measured, simultaneously. Nets with different porosities, colors and texture structures were used for the study. The short and long wave’s radiative properties of the nets were pre-determined in previous studies to be used. Re and Gr numbers were determined and used to characterize the convection mechanism over each net. The results showed that forced and mixed convection are the dominant modes existing over the nets during most of the day and night times. The nature of convection over nets depends mainly on the wind speed, net-air temperature difference and texture shape of the net rather than its color and its porosity.

scholarly journals Solar Extreme and Far Ultraviolet Radiation Modeling for Aeronomic Calculations

2021 ◽  
Vol 13 (8) ◽  
pp. 1454
Author(s):  
Anatoliy A. Nusinov ◽  
Tamara V. Kazachevskaya ◽  
Valeriya V. Katyushina
Keyword(s):  
Ultraviolet Radiation ◽  
Input Parameter ◽  
Solar Spectrum ◽  
Upper Atmosphere ◽  
Model Calculations ◽  
Radiation Fluxes ◽  
Main Components ◽  
Comparison Of The Results ◽  
Far Ultraviolet ◽  
Radiation Modeling

Modeling the upper atmosphere and ionospheres on the basis of a mathematical description of physical processes requires knowledge of ultraviolet radiation fluxes from the Sun as an integral part of the model. Aeronomic models of variations in the radiation flux in the region of extreme (EUV) and far (FUV) radiation, based mainly on the data of the last TIMED mission measurements of the solar spectrum, are proposed. The EUVT model describes variations in the 5–105 nm spectral region, which are responsible for the ionization of the main components of the earth’s atmosphere. The FUVT model describes the flux changes in the 115–242 nm region, which determines heating of the upper atmosphere and the dissociation of molecular oxygen. Both models use the intensity of the hydrogen Lyman-alpha line as an input parameter, which can currently be considered as one of the main indices of solar activity and can be measured with relatively simpler photometers. A comparison of the results of model calculations with observations shows that the model error does not exceed 1–2% for the FUVT model, and 5.5% for EUVT, which is sufficient for calculating the parameters of the ionosphere and thermosphere.

The local and remote atmospheric impacts of Africa’s 21st century aerosol emission trajectory

2021 ◽  
Author(s):  
Chris Wells ◽  
Apostolos Voulgarakis
Keyword(s):  
Regional Climate ◽  
Emission Region ◽  
Anthropogenic Aerosol ◽  
Remote Locations ◽  
Aerosol Emission ◽  
Radiation Fluxes ◽  
The World ◽  
Aerosol Emissions ◽  
The Impact ◽  
Lower Biomass

<p>Aerosols are a major climate forcer, but their historical effect has the largest uncertainty of any forcing; their mechanisms and impacts are not well understood. Due to their short lifetime, aerosols have large impacts near their emission region, but they also have effects on the climate in remote locations. In recent years, studies have investigated the influences of regional aerosols on global and regional climate, and the mechanisms that lead to remote responses to their inhomogeneous forcing. Using the Shared Socioeconomic Pathway scenarios (SSPs), transient future experiments were performed in UKESM1, testing the effect of African emissions following the SSP3-RCP7.0 scenario as the rest of the world follows SSP1-RCP1.9, relative to a global SSP1-RCP1.9 control. SSP3 sees higher direct anthropogenic aerosol emissions, but lower biomass burning emissions, over Africa. Experiments were performed changing each of these sets of emissions, and both. A further set of experiments additionally accounted for changing future CO<sub>2</sub> concentrations, to investigate the impact of CO<sub>2</sub> on the responses to aerosol perturbations. Impacts on radiation fluxes, temperature, circulation and precipitation are investigated, both over the emission region (Africa), where microphysical effects dominate, and remotely, where dynamical influences become more relevant. </p>

Surface radiation fluxes in transient climate simulations

1999 ◽  
Vol 20 (1) ◽  
pp. 33-55 ◽  
Author(s):  
J.R. Garratt ◽  
D.M. O'Brien ◽  
M.R. Dix ◽  
J.M. Murphy ◽  
G.L. Stephens ◽  
...  
Keyword(s):  
Surface Radiation ◽  
Radiation Fluxes ◽  
Climate Simulations

scholarly journals Modelling in Human Biometeorology: Spatial-Temporal Analysis of Thermal Indices

2021 ◽  
Vol 8 (1) ◽  
pp. 28
Author(s):  
Andreas Matzarakis ◽  
Marcel Gangwisch ◽  
Tim Herbert
Keyword(s):  
Meteorological Parameters ◽  
Meteorological Parameter ◽  
Temporal Analysis ◽  
Wave Radiation ◽  
Thermal Indices ◽  
Spatial And Temporal Scales ◽  
Mitigation And Adaptation ◽  
Radiation Fluxes ◽  
Scale Models ◽  
Radiant Temperature

The issue of the quantification of thermal comfort or heat stress on humans is in vogue nowadays. This is evident for indices, which are trying to quantify these effects. Most known indices are PET, modified PET, SET*, PT and UTCI. All thermal indices require the same thermo-physiological and meteorological parameters. Air temperature, air humidity, wind speed, and short and long wave radiation fluxes in terms of mean radiant temperature are the required meteorological parameters. For human thermo-physiology, information about heat production and clothing are required. The meteorological parameters have to be available in appropriate spatial and temporal scales depending on the target and the specific issues demanded. The appropriate spatial and temporal resolution data cannot only be delivered by measurement stations. Meso and micro scale models, which compute meteorological parameter and thermal indices, can be helpful in the development of mitigation and adaptation strategies in the era of climate change.

scholarly journals Estimation of Net Radiation using satellite based data inputs

2014 ◽  
Vol XL-8 ◽  
pp. 307-313 ◽  
Author(s):  
S. V. S. Sai Krishna ◽  
P. Manavalan ◽  
P. V. N. Rao
Keyword(s):  
Outgoing Longwave Radiation ◽  
Surface Air Temperature ◽  
Longwave Radiation ◽  
Surface Radiation ◽  
Shortwave Radiation ◽  
Net Radiation ◽  
Clear Sky ◽  
Statistical Measures ◽  
Indian Land ◽  
Radiation Fluxes

Daily net surface radiation fluxes are estimated for Indian land mass at spatial grid intervals of 0.1 degree. Two approaches are employed to obtain daily net radiation for four sample days viz., November 19, 2013, December 16, 2013, January 8, 2014 and March 20, 2014. Both the approaches compute net shortwave and net longwave fluxes, separately and sum them up to obtain net radiation. The first approach computes net shortwave radiation using daily insolation product of Kalpana VHRR and 15 days time composited broadband albedo product of Oceansat OCM2. The net outgoing longwave radiation is computed using Stefan Boltzmann equation corrected for humidity and cloudiness. In the second approach, instantaneous clear-sky net-shortwave radiation is estimated using computed clear-sky incoming shortwave radiation and the gridded MODIS 16-day time composited albedo product. The net longwave radiation is obtained by estimating outgoing and incoming longwave radiation fluxes, independently. In this, MODIS derived surface emissivity and skin temperature parameters are used for estimating outgoing longwave radiation component. In both the approaches, surface air temperature data required for estimation of net longwave radiation fluxes are extracted from India Meteorological Department’s (IMD) Automatic Weather Station (AWS) records. Estimates by the two different approaches are evaluated by comparing daily net radiation fluxes with CERES based estimates corresponding to the sample days, through statistical measures. The estimated all sky daily net radiation using the first approach compared well with CERES SYN1deg daily average net radiation with r<sup>2</sup> values of the order of 0.7 and RMS errors of the order of 8&ndash;16 w/m<sup>2</sup>.

scholarly journals A Hydrodynamical Model for Calculating the Vertical Temperature Profile in Lakes During Cooling

1983 ◽  
Vol 14 (4) ◽  
pp. 239-254 ◽  
Author(s):  
Jörgen Sahlberg
Keyword(s):  
Heat Flux ◽  
Temperature Profile ◽  
Vertical Mixing ◽  
Hydrodynamical Model ◽  
Measured Temperature ◽  
Vertical Temperature ◽  
Mixing Rate ◽  
Mixing Processes ◽  
Vertical Temperature Profile ◽  
Radiation Fluxes

A one-dimensional hydrodynamical model is used for simulating the vertical temperature profile in a lake during cooling conditions. The vertical mixing rate is calculated by solving the equations for turbulent kinetic energy, k, and dissipation of energy, ε. The heat exchange between the water and atmosphere consists of the radiation fluxes, sensible and latent heat flux. Temperature measurements from Lake Väsman during November-December, 1981, were used in the verification study. The agreement between calculated and measured temperature profiles is very good. This indicates that both the mixing processes and the net heat flux are well described in the model.

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