An improved equation for estimating diurnal atmospheric radiation near the surface in Japan

Light scattering property of environment is very important in theoretical study and application of the remote sensing. What's more, it is valuable for infrared radiation, imaging, and the detection of target and tracking. In this paper, solar and atmospheric background radiation, and their scattering property from target are discussed. BRDF (Biodirectional Reflectance Distribution Function) is a very important quantity that shows the radiation and reflection feature of target. According to electromagnetic radiant and scattering theories, the relationship between laser radar scattering cross section (LRCS) and BRDF is introduced. LOWTRAN model is an effective method of calculating the spectral distribution of solar and atmospheric radiation. Here it is applied to compute solar and atmospheric background radiation scattered from a target. The relative equations are deduced. Thus, the spatial and spectral distribution of scattering light is given. As a special example, for the Lambert's surface, the equations are simplified. As a result, the spatial and spectral distributions scattering radiation of solar and atmospheric background from a rough painted surface are present. The scattering of solar radiation plays a primary role in MIR region, but scattering of atmospheric background radiation is higher in LIR region. At the same time, there is obviously specular reflectance for solar radiation due to coherent scattering from rough surface.

Light scattering property of environment is very important in theoretical study and application of the remote sensing. What's more, it is valuable for infrared radiation, imaging, and the detection of target and tracking. In this paper, solar and atmospheric background radiation, and their scattering property from target are discussed. According to electromagnetic radiant and scattering theories, BRDF (Bidirectional Reflectance Distribution Function) is introduced. BRDF is a very important quantity that shows the radiation and reflection feature of target. Lowtran model is an effective method of calculating the spectral distribution of solar and atmospheric radiation. Here it is applied to compute solar and atmospheric background radiation, which is incident to target. The intensity of incident light and the scattering radiance are linked by BRDF. The relative equations are deduced. Thus, the light spatial and spectral scattering distribution is given. As a special example, for the Lambert's surface, the equations are simplified. As a result, the spatial and spectral distribution scattering curves of solar and atmospheric background radiation incident to target are present. They show the different spatial and spectral scattering features of target, at the same time, the coherent and incoherent scattering quantities are discussed.

Contemporary climatic models predicting different scenarios of climate formation are examined and educated on examples of known parameters of the climatic system of the last century. The atmospheric aerosols' impact is taken into account as adjusting factor. The cloud influence on increasing absorption of the solar radiation in the atmosphere (‘anomalous absorption’ in the short wavelength ranges) is not considered in the climatic simulations. Observations of the shortwave solar radiation in the Earth's atmosphere demonstrate increasing radiation absorption under cloudy conditions compared with the clear atmosphere. The difference between the spectral dependence of the cloud optical thickness together with the value of the single scattering albedo, retrieved from airborne, satellite and ground‐based radiation observations, and results of model calculations with applying scattering theory is revealed. A possible physical explanation is proposed in this paper. An incorrect account of the absorption of solar radiation in the cloudy atmosphere during the process of refining a climatic model attaches too much weight of the greenhouse gases yield on atmospheric energy balance in simulation. As a result, the influence of greenhouse gases on formation of the temperature field appears overestimated.

view Abstract Citations (52) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Diffuse cosmic and atmospheric MeV gamma radiation from balloon observations. Schoenfelder, V. ; Graser, U. ; Daugherty, J. Abstract Final results on diffuse cosmic and atmospheric gamma-radiation between 1.5 and 10 MeV from two balloon flights with a double Compton telescope flown from Palestine, Texas, in 1973 and 1974 are presented. From these flights, the energy spectrum of the diffuse cosmic gamma-ray component, its dependence on galactic latitude, the energy spectrum of the vertical atmospheric gamma-ray component at various atmospheric depths, and the zenith angle distribution of atmospheric gamma-radiation at 2.5 g/sq cm were determined. Publication: The Astrophysical Journal Pub Date: October 1977 DOI: 10.1086/155580 Bibcode: 1977ApJ...217..306S Keywords: Atmospheric Radiation; Balloon Sounding; Cosmic Rays; Diffuse Radiation; Gamma Rays; Compton Effect; Cosmic X Rays; Gamma Ray Astronomy; Radiation Measurement; X Ray Spectra; Space Radiation full text sources ADS |

In this chapter, in section 2.1 we discuss the propagation of electromagnetic radiation in the lower atmosphere. The refractive index and its variations with meteorological conditions and the effects of such variations on radio wave propagation are dealt with. In section 2.2, the scattering of radiation by hydrometeors and the derivation of meteorological parameters from radar-measured parameters is discussed. Scattering in clear air due to refractive index inhomogeneities is also considered. In section 2.3, the attenuation of radiation in the atmosphere by atmospheric gases and hydrometeors is discussed.

Abstract. Southern Ocean (SO) shortwave (SW) radiation biases are a common problem in contemporary general circulation models (GCMs), with most models exhibiting a tendency to absorb too much incoming SW radiation. These biases have been attributed to deficiencies in the representation of clouds during the austral summer months, either due to cloud cover or cloud albedo being too low. The problem has been the focus of many studies, most of which utilised satellite datasets for model evaluation. We use multi-year ship-based observations and the CERES spaceborne radiation budget measurements to contrast cloud representation and SW radiation in the atmospheric component Global Atmosphere (GA) version 7.1 of the HadGEM3 GCM and the MERRA-2 reanalysis. We find that the prevailing bias is negative in GA7.1 and positive in MERRA-2. GA7.1 performs better than MERRA-2 in terms of absolute SW bias. Significant errors of up to 21 W m−2 (GA7.1) and 39 W m−2 (MERRA-2) are present in both models in the austral summer. Using ship-based ceilometer observations, we find low cloud below 2 km to be predominant in the Ross Sea and the Indian Ocean sectors of the SO. Utilising a novel surface lidar simulator developed for this study, derived from an existing Cloud Feedback Model Intercomparison Project (CFMIP) Observation Simulator Package (COSP) – active remote sensing simulator (ACTSIM) spaceborne lidar simulator, we find that GA7.1 and MERRA-2 both underestimate low cloud and fog occurrence relative to the ship observations on average by 4 %–9 % (GA7.1) and 18 % (MERRA-2). Based on radiosonde observations, we also find the low cloud to be strongly linked to boundary layer atmospheric stability and the sea surface temperature. GA7.1 and MERRA-2 do not represent the observed relationship between boundary layer stability and clouds well. We find that MERRA-2 has a much greater proportion of cloud liquid water in the SO in austral summer than GA7.1, a likely key contributor to the difference in the SW radiation bias. Our results suggest that subgrid-scale processes (cloud and boundary layer parameterisations) are responsible for the bias and that in GA7.1 a major part of the SW radiation bias can be explained by cloud cover underestimation, relative to underestimation of cloud albedo.

Numerical model of scattering radiation in the earth atmosphere for scientific investigations and applications

The distribution of solar radiation in the earth's atmosphere: The effects of ozone, aerosols and clouds

The distribution of solar radiation in the earth's atmosphere: The effects of ozone, aerosols and clouds

The ARM Enhanced Shortwave Experiment (ARESE) II was conducted in spring 2000 to address unresolved issues about the absorption of solar radiation in the atmosphere in the presence of clouds. In this study, apparent atmospheric absorption derived from surface and aircraft measurements are compared to 3‐D radiative transfer model computations. Three cloud fields are examined with the heaviest overcast condition of 29 March being the most reliable from the standpoint of cloud structure and sampling. For this cloud field the model underestimates absorption by 18 W m−2 (9%) when compared to the Kipp and Zonen CM‐22s and by 35 W m−2 (18%) compared to the Scripps Institution for Oceanography Radiation Measurement System. By including aerosols with modest absorbing properties into the model computations, the discrepancy is isolated to the near‐infrared spectral region (0.68–3.9 μm). A comprehensive sensitivity analysis demonstrates that to match simultaneously the observed absorptance, transmittance, and cloud albedo with theory, cloud droplets must have optical properties similar to droplets with sizes three to four times as large as inferred in this study's cloud retrievals.

Transfer of visible radiation in the atmosphere

<p>The quantification of Earth’s solar radiation budget and its temporal changes is essential for the understanding of the genesis and evolution of climate on our planet. While the solar radiative fluxes in and out of the climate system can be accurately tracked and quantified from space by satellite programs such as CERES or SORCE, the disposition of solar energy within in the climate system is afflicted with larger uncertainties. A better quantification of the solar radiative fluxes not only under cloudy, but also under cloud-free conditions can help to reduce these uncertainties and is essential for example for the determination of cloud radiative effects or for the understanding of  temporal changes in the solar radiative components of the climate system.</p> <p>We combined satellite observations of Top of Atmosphere fluxes with the information contained in surface flux observations and climate models to infer the absorption of solar radiation in the atmosphere, which we estimated at 73 Wm<sup>-2</sup> globally under cloud-free conditions (Wild et al. 2019 Clim Dyn). The latest generation of climate models participating in CMIP6 is now able to reproduce this magnitude surprisingly well, whereas in previous climate model  generations the cloud-free atmosphere was typically too transparent for solar radiation, which stated a long-standing modelling issue (Wild 2020 Clim Dyn, Wild et al. 1995 JClim).</p> <p>With respect to changes in solar fluxes, there is increasing evidence that the substantial long-term decadal variations in surface solar radiation known as dimming and brightening occur not only under all-sky, but similarly also under clear-sky conditions (Manara et al. 2016 ACP, Yang et al. 2019 JClim; Wild et al. 2021 GRL). This points to aerosol radiative effects as major factor for the explanation of this phenomenon.</p>

An integrated naval infrared target, countermeasure and threat model is presented. The target modeling capabilities include complex 3-D surface geometries, a thermal system model with auto-generated solar heating, sea/air convection, sea/sky radiation and inter-surface radiation, a surface radiance model which accounts for multiple diffuse reflections, observer-to-target atmospheric absorption and path radiance, and an exhaust gas dispersion and IR emission model. The IR images of any number of targets can be rendered simultaneously within a full-hemispherical sea/sky/sun background relative to an observer at a specified altitude, based on the atmospheric radiance, solar irradiance, path radiance and time-average solar sea-glint. Flare countermeasures are added to the scenario through definition of canisters, submunitions, burn characteristics and deployment tactics. The IR missile model has been constructed from a minimum number of parameters to keep the model generic and provide a reasonable estimate of IR susceptibility. The purpose of the model is to provide the tools necessary to develop and assess the effectiveness of infrared signature suppression and infrared countermeasures. A number of analysis methods are provided, including on- screen image analysis, polar signature plots, polar lock-on range and engagement simulation.

A theoretical analysis of atmospheric thermal radiation reveals that previous formulas relating this parameter to screen-level air temperature have lacked universal applicability. New considerations indicate that the effective emittance of the atmosphere is a minimum at 273°K and that it increases symmetrically to approach unity exponentially at higher and lower temperatures. A formula is developed that meets these standards and fits experimental data from Alaska, Arizona, Australia, and the Indian Ocean with a correlation coefficient of 0.992. The atmospheric radiation R integrated over all wavelengths, is specified solely in terms of the screen-level air temperature T as R = σT4{1 - c exp [−d (273 - T)2]}, where c and d are constants having values of 0.261 and 7.77×10−4, respectively. It appears that the formula may be valid at all latitudes and seasons.

Radiative kernel is a widely adopted method for diagnosing radiation variability and climate feedback. However, most of the existing radiative kernels are broadband flux kernels and lack the spectral information. Motivated by the growing interest in the spectral changes of the Earth radiation budget, we generate a new set of band-by-band radiative kernels based on the fifth generation European Center for Medium-Range Weather Forecasts (ERA5) reanalysis, which can be used for analyzing the spectrally decomposed changes in the top of atmosphere, surface and atmospheric radiation. The radiative sensitivity quantified by the ERA5 band-by-band kernel is compared to another spectral kernel and validated in a spectral radiation closure test. The use and benefits of the new ERA5 kernels are then demonstrated in an analysis of spectral feedbacks of an ensemble of global climate models (GCMs).