Table 6‑2: Electromagnetic radiation values
|
Solar constant at 1 AU |
1 366,1 W m-2 |
|
Solar energy flux at aphelion |
1 321,6 W m-2 |
|
Solar energy flux at perihelion |
1 412,9 W m-2 |
|
NOTE The solar constant, a historical term, is not constant. It varies geometrically with the Earth’s distance from the sun and physically with the sun’s magnetic field activity on short to long timescales, as well as with the observer’s heliocentric latitude. The value of 1 366,1 W m-2 is the measurement community’s current agreement. The currently measured 1-sigma variation of the composite dataset of space based measurements is approximately 0,6 W m-2 and there is a long-term (yearly) smoothed solar cycle minimum to maximum relative variation about the mean value of approximately 1,4 W m-2[RD.2]. |
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