The impact of season, cloud cover and air pollution on the different spectral regions of ultraviolet and visible incident solar radiation at the surface

After shading a light on the extraterrestrial solar radiation in the chapter 3 it is important to evaluate the global terrestrial solar radiation and its components. The information on terrestrial solar radiation is required in several different forms depending on the kinds of calculations and kind of application that are to be done. Of course, terrestrial solar radiation on the horizontal plane depends on the different weather conditions such as cloud cover, relative humidity, and ambient temperature. Therefore, the impact of the atmosphere on solar radiation should be considered. One of the most important points of terrestrial solar radiation evaluation is its determination during clear sky conditions. Therefore, in this chapter, the equations that determine the air mass basing on available theories are given and the clear sky conditions are introduced with shading a light on the previous work in identifying clear sky conditions. Taking into consideration that, clear sky solar radiation estimation is of great importance for solar tracking, a detailed review of main available models is given in this chapter. As daily, monthly, seasonally, biannually and yearly mean daily solar radiations are required information for designing and installing long term tracking systems, different available methods are commented regarding their applicability for the estimation of solar radiation information in the desired format from the data that are available. An important accent is paid also on the assessment and comparison of monthly mean daily solar radiation estimation models.

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Annual evolution of global, direct and diffuse radiation and fractions in tilted surfaces

Engenharia Agrícola ◽

10.1590/s0100-69162012000200005 ◽

2012 ◽

Vol 32 (2) ◽

pp. 247-260

Author(s):

Adilson P. de Souza ◽

João F. Escobedo ◽

Alexandre Dal Pai ◽

Eduardo N. Gomes

Keyword(s):

Solar Radiation ◽

Cloud Cover ◽

Diffuse Radiation ◽

Incident Radiation ◽

Sao Paulo ◽

Horizontal Surface ◽

Direct Radiation ◽

Incident Solar Radiation ◽

Cover Ratio ◽

Atmospheric Transmissivity

It was evaluated the annual evolution of global, direct and diffuse components of incident solar radiation on tilted surfaces to 12.85, 22.85 and 32.85º, facing north, in Botucatu, state of São Paulo, Brazil. The radiometric fractions were obtained for each component of the radiation in the aforementioned surfaces, through the ratio with the global and top of the atmosphere radiations. Seasonality was evaluated based on monthly averages of daily values. The measures occurred between 04/1998 and 07/2001 at 22.85º; 08/2001 and 02/2003 at 12.85º; and from 03/2003 to 12/2007 at 32.85º, with concomitant measures in the horizontal surface (reference). The levels of global and direct radiation on tilted surfaces were lower in summer and higher in the equinoxes when compared with the horizontal. The diffuse radiation on tilted surfaces was lower in most months, with losses of up to 65%. A trend of increasing differences occurred between horizontal and tilted surfaces with the increase of the angle in all the components and fractions of incident radiation. The annual evolution of rainfall and cloud cover ratio directly affected the atmospheric transmissivity of direct and diffuse components in the region.

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Homogenized century-long surface incident solar radiation over Japan

10.5194/essd-2021-231 ◽

2021 ◽

Author(s):

Qian Ma ◽

Kaicun Wang ◽

Yanyi He ◽

Liangyuan Su ◽

Qizhong Wu ◽

...

Keyword(s):

Time Series ◽

Solar Radiation ◽

Cloud Cover ◽

Sunshine Duration ◽

Sharp Decrease ◽

Dust Storms ◽

Radiative Effect ◽

Incident Solar Radiation ◽

Global Dimming ◽

Asian Dust Storms

Abstract. Surface incident solar radiation (Rs) plays an essential role in climate change on Earth. Rs can be directly measured, and it shows substantial variability, i.e., global dimming and brightening, on decadal scales. Rs can also be derived from the observed sunshine duration (SunDu) with reliable accuracy. The SunDu-derived Rs was used as a reference to detect and adjust the inhomogeneity in the observed Rs. However, both the observed Rs and SunDu-derived Rs may have inhomogeneity. In Japan, SunDu has been measured since 1890, and Rs has been measured since 1961 at ~100 stations. In this study, the observed Rs and SunDu-derived Rs were first checked for inhomogeneity with a statistical software RHtest. If confirmed by the metadata of these observations, the detected inhomogeneity was adjusted based on the RHtest-quantile matching method. Second, the two homogenized time series were compared to detect further possible inhomogeneity. If confirmed by the independent ground-based observations of cloud cover fraction, the detected inhomogeneity was adjusted based on the reference dataset. As a result, a sharp decrease in the observed Rs from 1961 to 1975 caused by instrument displacement was detected and adjusted. Similarly, a gradual decline in SunDu-derived Rs due to steady instrument replacement from 1985 to 1990 was detected and adjusted. After homogenization, the two estimates agree well. Rs was found to have increased at a rate of 0.9 W m−2 per decade (p < 0.01) from 1961 to 2015 based on the homogenized SunDu-derived Rs, which was enhanced by a positive aerosol-related radiative effect (2.2 W m−2 per decade) and diminished by a negative cloud cover radiative effect (−1.4 W m−2 per decade). The brightening over Japan was the strongest in spring, likely due to a significant decline in aerosol transported from Asian dust storms. The observed raw Rs data and their homogenized time series used in this study are available at https://doi.org/10.11888/Meteoro.tpdc.271524 (Ma et al., 2021).

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Cosmic Rays and Clouds Variations Effect on the Climate is Insignificantly

Applied Physics Research ◽

10.5539/apr.v10n4p81 ◽

2018 ◽

Vol 10 (4) ◽

pp. 81

Author(s):

H. I. Abdussamatov

Keyword(s):

Cosmic Rays ◽

Solar Radiation ◽

Little Ice Age ◽

Cloud Cover ◽

Galactic Cosmic Rays ◽

Lower Atmosphere ◽

Ice Age ◽

Additional Source ◽

The Earth ◽

The Impact

It is believed that an increase in the area of the cloud cover in the lower atmosphere of the Earth caused by the influence grows of galactic cosmic rays in the period of the Grand minimum of solar activity lead to an increase the reflected part of incoming solar radiation back into space and by that to a cooling of the climate down to the Little Ice Age. We will try to estimate an inverse aspect of simultaneously influence of increase in the area of the cloud cover in to the narrowing of the transmission of the windows of atmospheric transparency, which practically compensates of this cooling by means of accumulation of energy. An increase in the reflection of the thermal radiation of the Earth surface and of the solar radiation reflected from it, as well as the significant amplification of the greenhouse effect, presents an important additional source of heating due to the increase in the area of the cloud cover in the lower atmosphere. The impact of the increase in the area of the cloud cover caused by the influence grows of cosmic rays on the climate is very small.

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Absence of the Impact of the Flux of Cosmic Rays and the Cloud Cover on the Energy Balance of the Earth

Journal of Atmospheric Science Research ◽

10.30564/jasr.v3i3.2129 ◽

2020 ◽

Vol 3 (3) ◽

Author(s):

H. I. Abdussamatov

Keyword(s):

Energy Balance ◽

Cosmic Rays ◽

Solar Radiation ◽

Thermal Radiation ◽

Cloud Cover ◽

Transparency Window ◽

Lower Atmosphere ◽

Atmospheric Transparency ◽

The Earth ◽

The Impact

The energy of solar radiation absorbed by the Earth, as well as the thermal radiation of the Earth’s surface, which is released to the space through the atmospheric transparency window, depends on variations of the area of the cloud cover. Svensmark et al. suggest that the increase in the area of the cloud cover in the lower atmosphere, presumably caused by an increase in the flux of galactic cosmic rays during the quasi-bicentennial minimum of solar activity, results only in an increase in the fraction of the solar radiation reflected back to the space and weakens the flux of the solar radiation that reached the Earth surface. It is suggested, without any corresponding calculations of the variations of the average annual energy balance of the Earth Е, that the consequences will include only a deficit of the solar energy absorbed by the Earth and a cooling of the climate up to the onset of the Little Ice Age. These suggestions ignore simultaneous impact of the opposite aspects of the increase in the area of the cloud cover on the climate warming. The latter will result from a decrease in the power of thermal radiation of the Earth’s surface released to the space, and also in the power of the solar radiation reflected from the Earth’s surface, due to the increase in their absorption and reflection back to the surface. A substantial strengthening in the greenhouse effect and the narrowing of the atmospheric transparency window will also occur. Here, we estimate the impact of all aspects of possible long-term 2% growth of the cloud cover area in the lower atmosphere by Е. We found that an increase in the cloud cover area in the lower atmosphere will result simultaneously both in the decrease and in the increase in the temperature, which will virtually compensate each other, while the energy balance of the Earth E before and after the increase in the cloud cover area by 2% will stay essentially the same: E1 – Eо ≈ 0.

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Clouds damp the impacts of Polar sea ice loss

10.5194/tc-2019-283 ◽

2019 ◽

Author(s):

Ramdane Alkama ◽

Alessandro Cescatti ◽

Patrick C. Taylor ◽

Lorea Garcia-San Martin ◽

Herve Douville ◽

...

Keyword(s):

Solar Radiation ◽

Sea Ice ◽

Cloud Cover ◽

Climate Models ◽

Arctic Sea Ice ◽

Ice Melting ◽

Ice Retreat ◽

Sea Ice Retreat ◽

The Impact

Abstract. Clouds plays an important role on the climate system through two main contrasting effects: (1) cooling the Earth by reflecting to space part of incoming solar radiation; (2) warming the surface by reducing the Earth’s loss of thermal energy to space. Recently, scientists have paid more attention to the warming role of clouds because of the acceleration of Arctic sea ice melting and because of recent studies that did not find any response of cloud cover fraction to reduced sea ice in summer. On the contrary, with this work based on satellite CERES data and 32 CMIP5 climate models, we reveal that the cooling role of clouds is dominant. Indeed, cloud dynamic occurring in combination with sea-ice melting plays an important cooling effect by altering the surface energy budget in an apparently contradicting way: years with less sea ice are also those that show an increase of the radiative energy reflected back to space by clouds. An increase in absorbed solar radiation when sea ice retreats (surface albedo change) explains 66 ± 2 % of the observed signal. The remaining 34 ± 1 % are due to the increase in cloud cover/thickness when sea ice retreat and associated reflection to space. This interplay between clouds and sea ice reduces by half the increase of net radiation at the surface that follows the sea-ice retreat, therefore damping the impact of polar sea ice loss. We further highlight how this process is mis-represented in some climate models.

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