From Big Medical Encyclopedia

SOLAR RADIATION - the radiation of the electromagnetic and corpuscular nature proceeding from the Sun.

The main part of a radiation energy of the Sun is the share of a visible and infrared part of an electromagnetic range (see Radiations, Infrared radiation , Light), and also Uv-radiation (see. Ultraviolet radiation ). The smaller share of Neuter is made by radiation in a x-ray part of a range, in radio frequency range and in the form of corpuscles.

In the atmosphere of Earth a considerable part of ultraviolet and infrared radiation of the Sun is absorbed; a short-wave part of Uv-radiation is absorbed by ozone in an upper atmosphere of Earth, and also the water vapors, particles of dust and smoke which are contained in the atmosphere; x-ray emission of the Sun is completely absorbed by the atmosphere. Corpuscular radiation of the Sun consists generally of bystry protons with energy about 10 3 — 10 10 ev. Only particles with energy over 4,5 * 10 get into the terrestrial atmosphere 8 ev. At the height of 300 km dosage rate of radiation during the periods of solar flashes increases in hundreds and thousands of times, however on the Earth's surface the space background increases slightly — approximately by 15% (see. Ionizing radiation ).

Intensity of Neuter on the Earth's surface (see Insolation) depends on the latitude of the area, the period of year, time of day, and also on cloudiness and transparency of the atmosphere. In cloudless day at middle latitudes at noon illumination at the expense of Neuter can reach 100 thousand lx. With cloudiness this size decreases approximately by 100 times. The flow of Neuter falling on 1 cm2 of the area on border of the terrestrial atmosphere makes 136 mt: the size equal 136 met/sm1, is called a solar constant.

Neuter is the main source of energy for the majority of the processes happening on Earth. Terrestrial plants (see) acquire energy of the Sun, synthesize various organic matters (see Photosynthesis), to-rye then are used animal, incapable of independent synthesis of these substances.

In the course of evolution many human organs and animals adapted to existence in the conditions of Neuter. So, the structure of an eye of the person, spectral properties of his receptors are optimum adapted for perception of Neuter in a visible part of his range (see. Sight ). At the same time the maximum of sensitivity of an eye corresponds to a maximum in a radiation spectrum of Neuter in the afternoon. Both low intensity of sunlight, and their high values can cause exhaustion of eyes. It defines the choice a gigabyte. standards of illumination in workplaces depending on a sort of work (see. Lighting ).

Neuter renders defined biol. effect on a human body and animals (see. Light biological effect ). Neuter is widely used in to lay down. the purposes (see. Heliation , Climatotherapy ). At the same time both time of influence of Neuter, and total number of such radiations which are carried out usually on beaches or in special aero sunbeds is dosed. The beneficial influence of moderate doses of Uv-radiation on skin is connected by hl. obr. with formation of vitamin D at radiation. Excessive influence of Neuter can cause a number of skin, vascular, eye and other diseases. Also oncogenous action of radiation by Uv-radiation in high doses is known. Long finding in the conditions of intensive of Neuter can cause solar, or thermal shock (see).

See also Photobiology .

Bibliography: Galanin N. F. Radiant energy and its hygienic value, L., 1969, bibliogr.; P and r f e N about in A. P. Physical remedies and resort factors. L., 1968; P e m and z about in A. N. Kurs of physics, electronics and cybernetics for medical institutes, M., 1982; H at and N with to and y S. M. Beams of the sun and their action on a human body, M.,

1959, bibliogr.

Yu. M. Petrusevich.