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The average annual solar radiation arriving at the top of the Earth's atmosphere is about 1361 W/m 2. This represents the power per unit area of solar irradiance across the spherical surface surrounding the Sun with a radius equal to the distance to the Earth (1 AU).
The actual direct solar irradiance at the top of the atmosphere fluctuates by about 6.9% during a year (from 1.412 kW/m 2 in early January to 1.321 kW/m 2 in early July) due to the Earth's varying distance from the Sun, and typically by much less than 0.1% from day to day.
Earth's energy balance and imbalance, showing where the excess energy goes: Outgoing radiation is decreasing owing to increasing greenhouse gases in the atmosphere, leading to Earth's energy imbalance of about 460 TW. [1] The percentage going into each domain of the climate system is also indicated.
Most of the world's population live in areas with insolation levels of 150–300 watts/m 2, or 3.5–7.0 kWh/m 2 per day. [8] Solar radiation is absorbed by the Earth's land surface, oceans – which cover about 71% of the globe – and atmosphere. Warm air containing evaporated water from the oceans rises, causing atmospheric circulation or ...
The rep has variously been defined as 83 or 93 ergs per gram of tissue (8.3/9.3 mGy) [13] or per cc of tissue. [ 14 ] In 1953 the ICRU recommended the rad, equal to 100 erg/g as a new unit of absorbed radiation, [ 15 ] but then promoted a switch to the gray in the 1970s.
They additionally receive a substantial internal dose from radon. Record radiation levels were found in a house where the effective dose due to ambient radiation fields was 131 mSv (13.1 rem) per year, and the internal committed dose from radon was 72 mSv (7.2 rem) per year. [28]
The CCU decided to define the SI unit of absorbed radiation as energy deposited by reabsorbed charged particles per unit mass of absorbent material, which is how the rad had been defined, but in MKS units it would be equivalent to the joule per kilogram. This was confirmed in 1975 by the 15th CGPM, and the unit was named the "gray" in honour of ...
Radiation fluence is the number of radiation particles impinging per unit area per unit time, ... 8 h = 1 day 40 h = 1 week 50 weeks = 1 year. Therefore, for ...