Chapter 5 Solar Radiation Inflow and the Natural Irradiance in the Sea. The Apparent Optical Properties of the Sea

2021 ◽  
Author(s):  
Bingbing Duan ◽  
Urs Hugentobler ◽  
Inga Selmke ◽  
Stefan Marz

<p>A physical a priori box-wing solar radiation pressure (SRP) model is widely used by most analysis centers for Galileo and QZSS (Quasi-Zenith Satellite System) satellites, complemented by an ECOM or ECOM2 (Empirical CODE Orbit Model) model. For the other constellations, for instance GPS and GLONASS satellites, optical properties of satellite surfaces are not publicly available, especially for GPS Block IIF and GLONASS satellites. By fixing satellite surface areas and total mass to the values from some unpublished documents, we estimate satellite surface optical properties based on true GNSS measurements covering long time periods (typically this should be longer than a full beta angle time range to reduce correlations between parameters). Meanwhile, various physical effects are considered, such as yaw bias, radiator emission and thermal radiation of solar panels. We find that yaw bias of GPS Block IIA and IIR satellites does not dominate the Y-bias, it is likely that heat generated in the satellite is radiated from louvers or heat pipes on the Y side of the satellite. It is also noted that the ECOM Y0 estimates of both GPS and GLONASS satellites show clear anomaly during eclipse seasons. This indicates that the radiator emission is present when the satellite crosses shadows. Since satellite attitude during eclipse seasons could be different from the nominal yaw, potential radiator effect in the –X surface could be wrongly absorbed by the ECOM Y0 as well. By considering all the estimated parameters in an a priori model we observe clear improvement in satellite orbits, especially for GLONASS satellites. China’s Beidou-3 satellites are now providing PNT (positioning, navigation and timing) service globally. Satellite attitude, dimensions and total mass are publicly available. Also, the absorption optical properties of each satellite surface are given. With all this information, we estimate the other optical properties of Beidou satellites considering similar yaw bias, radiator and thermal radiation effects as those in GPS and GLONASS satellites.</p>


2014 ◽  
Vol 48 (17) ◽  
pp. 10217-10226 ◽  
Author(s):  
Hyun Ji (Julie) Lee ◽  
Paige Kuuipo Aiona ◽  
Alexander Laskin ◽  
Julia Laskin ◽  
Sergey A. Nizkorodov

2019 ◽  
Author(s):  
Radiance Calmer ◽  
Gregory C. Roberts ◽  
Kevin J. Sanchez ◽  
Jean Sciare ◽  
Karine Sellegri ◽  
...  

Abstract. In the framework of the EU-FP7 BACCHUS project, an intensive field campaign was performed in Cyprus (2015/03). Remotely Piloted Aircraft System (RPAS), ground-based instruments, and remote-sensing observations were operating in parallel to provide an integrated characterization of aerosol-cloud interactions. Remotely Piloted Aircraft (RPA) were equipped with a 5-hole probe, pyranometers, pressure, temperature and humidity sensors, and measured updraft velocity at cloud base and cloud optical properties of a stratocumulus layer. Ground-based measurements of dry aerosol size distributions and cloud condensation nuclei spectra, and RPA observations of vertical wind velocity and meteorological state parameters are used here to initialize an Aerosol–Cloud Parcel Model (ACPM) and compare the in situ observations of cloud optical properties measured by the RPA to those simulated in the ACPM. Two different cases are studied with the ACPM, including an adiabatic case and an entrainment case, in which the in-cloud temperature profile from RPA is taken into account. Adiabatic ACPM simulation yields cloud droplet number concentrations at cloud base (ca. 400 cm−3) that are similar to those derived from a Hoppel minimum analysis. Cloud optical properties have been inferred using the transmitted fraction of shortwave radiation profile measured by downwelling and upwelling pyranometers mounted on a RPA, and the observed transmitted fraction of solar radiation is then compared to simulations from the ACPM. ACPM simulations and RPA observations show better agreement when associated with entrainment compared to that of an adiabatic case. The mean difference between observed and adiabatic profiles of transmitted fraction of solar radiation is 0.12, while this difference is only 0.03 between observed and entrainment profiles. A sensitivity calculation is then conducted to quantify the relative impacts of two-fold changes in aerosol concentration, and updraft velocity to highlight the importance of accounting for the impact of entrainment in deriving cloud optical properties, as well as the ability of RPAs to leverage ground-based observations for studying aerosol–cloud interactions.


2010 ◽  
Vol 37 (4) ◽  
Author(s):  
Rei Kudo ◽  
Akihiro Uchiyama ◽  
Akihiro Yamazaki ◽  
Tomonori Sakami ◽  
Eriko Kobayashi

2016 ◽  
Vol 144 ◽  
pp. 136-142 ◽  
Author(s):  
M. Karami ◽  
M.A. Akhavan-Behabadi ◽  
M. Raisee Dehkordi ◽  
S. Delfani

2007 ◽  
Vol 7 (1) ◽  
pp. 753-783 ◽  
Author(s):  
N. Hatzianastassiou ◽  
C. Matsoukas ◽  
E. Drakakis ◽  
P. W. Stackhouse ◽  
P. Koepke ◽  
...  

Abstract. A global estimate of the seasonal direct radiative effect (DRE) of natural plus anthropogenic aerosols on solar radiation under all-sky conditions is obtained by combining satellite measurements and reanalysis data with a spectral radiative transfer model. The estimates are obtained with detailed spectral model computations separating the ultraviolet (UV), visible and near-infrared wavelengths. The global distribution of spectral aerosol optical properties was taken from the Global Aerosol Data Set (GADS) whereas data for clouds, water vapour, ozone, carbon dioxide, methane and surface albedo were taken from various satellite and reanalysis datasets. Using these aerosol properties and other related variables, we generate climatological (for the 12-year period 1984–1995) monthly mean aerosol DREs. The global annual mean DRE on the outgoing SW radiation at the top of atmosphere (TOA, ΔFTOA) is 1.62 Wm−2 (with a range of –10 to 15 Wm−2, positive values corresponding to planetary cooling), the effect on the atmospheric absorption of SW radiation (ΔFatmab) is 1.6 Wm−2 (values up to 35 Wm−2, corresponding to atmospheric warming), and the effect on the surface downward and absorbed SW radiation (Δ Fsurf, and ΔFsurfnet, respectively) is –3.93 and –3.22 Wm−2 (values up to –45 and –35 Wm−2, respectively, corresponding to surface cooling.) According to our results, aerosols decrease/increase the planetary albedo by –3 to 13% at the local scale, whereas on planetary scale the result is an increase of 1.5%. Aerosols can warm locally the atmosphere by up to 0.98 K day−1, whereas they can cool the Earth's surface by up to –2.9 K day−1. Both these effects, which can significantly modify atmospheric dynamics and the hydrological cycle, can produce significant planetary cooling on a regional scale, although planetary warming can arise over highly reflecting surfaces. The aerosol DRE at the Earth's surface compared to TOA can be up to 15 times larger at the local scale. The largest aerosol DRE takes place in the northern hemisphere both at the surface and the atmosphere, arising mainly at ultraviolet and visible wavelengths.


2019 ◽  
Vol 126 (3) ◽  
pp. 374
Author(s):  
Л.Г. Астафьева ◽  
В.К. Пустовалов ◽  
В. Фритче

AbstractProblems related to using nanoparticles for absorption of solar radiation and photothermal nanotechnologies are now being actively studied. The efficiency of using nanoparticles as photothermal agents for solar energy is determined by their spectral optical properties. We performed computer simulation of optical properties of homogeneous metal (nickel, titanium, and molybdenum) nanoparticles and their oxides, along with nanoparticles consisting of a metal core and an oxide shell, with radii in the range from 50 to 100 nm in the spectral interval between 200 and 2500 nm. The influence of nanoparticle radius, the type of metal and its oxide on spectral coefficients of efficiency absorption ( K _abs) and scattering ( K _sca) of radiation by nanoparticles is investigated. The type of nanoparticles suitable for absorption of solar radiation was chosen based on a comparative analysis of the wavelength dependences of absorption efficiency coefficients K _abs, intensity of solar radiation I _ S , and parameter P _1 = K _abs/ K _sca. Spherical double–layer nanoparticles consisting of nickel or titanium core and oxide shells with a radius of 75 or 100 nm can be used in the spectral interval from 200 to 2500 nm for efficient absorption of solar radiation. These results are a substantial contribution to the investigation of optical properties of nanoparticles that can be used in systems of thermal energy.


Author(s):  
Ahmet Murat Mecit ◽  
Fletcher Miller

Concentrated solar power (CSP) systems use heliostats to concentrate solar radiation in order to produce heat, which drives a turbine to generate electricity. We, the Combustion and Solar Energy Laboratory at San Diego State University, are developing a new type of receiver for power tower CSP plants based on volumetric absorption by a gas-particle suspension. The radiation enters the pressurized receiver through a window, which must sustain the thermal loads from the concentrated solar flux and infrared reradiation from inside the receiver. The window is curved in a dome shape to withstand the pressure within the receiver and help minimize the stresses caused by thermal loading. It is highly important to estimate how much radiation goes through the window into the receiver and the spatial and directional distribution of the radiation. These factors play an important role in the efficiency of the receiver as well as window survivability. Concentrated solar flux was calculated with a computer code called MIRVAL from Sandia National Laboratory which uses the Monte Carlo Ray Trace (MCRT) method. The computer code is capable of taking the day of the year and time of day into account, which causes a variation in the flux. Knowing the concentrated solar flux, it is possible to calculate the solar radiation through the window and the thermal loading on the window from the short wavelength solar radiation. The MIRVAL code as originally written did not account for spectral variations, but we have added that capability. Optical properties of the window such as the transmissivity, absorptivity, and reflectivity need to be known in order to trace the rays at the window. A separate computer code was developed to calculate the optical properties depending on the incident angle and the wavelength of the incident radiation by using data for the absorptive index and index of refraction for the window (quartz) from other studies and vendor information. This method accounts for regions where the window is partially transparent and internal absorption can occur. A third code was developed using the MCRT method and coupled with both codes mentioned above to calculate the thermal load on the window and the solar radiation that enters the receiver. Thermal load was calculated from energy absorbed at various points throughout the window. In our study, window shapes from flat to concave hemispherical, as well as a novel concave ellipsoidal window are considered, including the effect of day of the year and time of the day.


Sign in / Sign up

Export Citation Format

Share Document