The TIM would have used four radiometers designed to measure the solar irradiance to an accuracy of 0.01 percent.
Exposure to increased temperatures and solar irradiance also causes zooxanthellae to manufacture abnormally large quantities of reactive oxygen species (molecules that contain oxygen and at least one unpaired electron), which are toxic to both the algae and their coral symbionts.
When an electromagnetic wave is absorbed by an object, the wave exerts a pressure (P) on the object that equals the wave's irradiance (I) divided by the speed of light (c): P = I/c newtons per square metre.
It may result from increases in seawater temperature, particularly when associated with elevated levels of solar irradiance (e.g., ultraviolet radiation), or it may be caused by changes in seawater chemistry (e.g., due to ocean acidification or pollution), increased levels of sediment in seawater, or a coral's exposure to sodium cyanide (a chemical used in the capture of coral reef fish).
Radiative forcing, as defined by the Intergovernmental Panel on Climate Change (IPCC), is a measure of the influence a given greenhouse gas or other climatic factor (such as solar irradiance or albedo) has on the amount of downward-directed radiant energy impinging upon Earth's surface.
The irradiance of sunlight at the top of Earth's atmosphere is about 1,350 watts per square metre; this factor is referred to as the solar constant.
The time-averaged irradiance I for a harmonic electromagnetic wave is related to the amplitudes of the electric and magnetic fields: I = ε0c2E0B0/2 watts per square metre.
The proper measure of energy transport in an electromagnetic wave is its irradiance, or intensity, which equals the rate at which energy passes a unit area oriented perpendicular to the direction of propagation.
Inside one of these solar thermal systems "is what I like to call a sun sponge or the absorber, the part that inverts the irradiance of the sun into useful heat".
