What Is Solar Radiation?

Solar radiation refers to the outward transmission of energy by the sun in the form of electromagnetic waves ^[1] , and refers to the electromagnetic waves and particle streams emitted by the sun into the universe. The energy transferred by solar radiation is called solar radiant energy. Although the solar radiant energy received by the earth is only one-two billionths of the total radiant energy radiated by the sun into space, it is the main source of energy for the movement of the earth's atmosphere and the main source of light and heat for the earth.

Solar radiation intensity refers to the strength of solar radiation reaching the ground. The absorption, reflection, and scattering of solar radiation by the atmosphere has greatly weakened the solar radiation reaching the ground. However, there are still many factors that affect the strength of solar radiation, making the amount of solar radiation reaching different areas different. There are four main factors affecting the strength of solar radiation. ^[4]

Day and night are caused by the rotation of the earth, and seasons are caused by the angle between the rotation axis of the earth and the rotation axis of the earth's orbit around the sun at 23 ° 27 . Every day the earth passes by itself

The radiation or "solar radiation" that the sun hits the ground plane consists of two parts-direct solar radiation and diffuse solar radiation. When solar radiation passes through the atmosphere and reaches the ground, it is caused by the absorption, reflection and reflection of solar radiation in the atmosphere by air molecules, water vapor and dust.

The wavelength of solar energy

The wavelength distribution of solar energy can be simulated by a blackbody radiation, the temperature of the blackbody is 5800K. Solar wavelength distribution at

Cosmic microwave background radiation

Atmospheric absorption ground

Effects of infrared radiation

Between ground and atmosphere

The radiant energy comes from the energy produced by the fusion of hydrogen nuclei. Under high temperature and pressure, 4

The sum of direct solar radiation and scattered radiation reaching the ground after the atmosphere weakens is called total solar radiation. On a global average, total solar radiation only accounts for 45% of solar radiation reaching the upper atmosphere. Total radiation decreases with increasing latitude and increases with increasing altitude. It is the largest around noon in a day, and it is 0 at night; it is big in summer and small in one year.

Solar radiation accounts for 50%, 43%, and 7% of visible light (0.4 to 0.76m), infrared (> 0.76m), and ultraviolet (<0.4m), respectively, that is, concentrated in the short-wave band, so solar radiation is called short-wave radiation.

The solar radiation test is an assessment of the ability of outdoor unshielded equipment to withstand the heat and optical effects of solar radiation.

Solar radiation test standards:

GJB 150.7-86 Environmental test methods for military equipment Solar radiation test

GB 4797.4-1989 Natural environmental conditions for electric and electronic products Solar radiation and temperature

GB / T 2423.24-1995 Environmental test for electric and electronic products Part 2: Test method Test Sa: Simulate solar radiation on the ground

At the beginning of this century, there were very few laboratories capable of conducting solar radiation test tests. Beijing has an environmental reliability and electromagnetic compatibility test service center, and one in Shanghai and one in Guangzhou.