Search results
Results from the WOW.Com Content Network
Albedo (/ æ l ˈ b iː d oʊ / al-BEE-doh; from Latin albedo ' whiteness ') is the fraction of sunlight that is diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects all incident radiation).
The Bond albedo is a value strictly between 0 and 1, as it includes all possible scattered light (but not radiation from the body itself). This is in contrast to other definitions of albedo such as the geometric albedo, which can be above 1. In general, though, the Bond albedo may be greater or smaller than the geometric albedo, depending on ...
Earth has an albedo of about 0.306 and a solar irradiance (L / 4 π D 2) of 1361 W m −2 at its mean orbital radius of 1.5×10 8 km. The calculation with ε=1 and remaining physical constants then gives an Earth effective temperature of 254 K (−19 °C). [11] The actual temperature of Earth's surface is an average 288 K (15 °C) as of 2020. [12]
As the difference in albedo between ice and e.g. ocean is around 2/3, this means that due to a 1 °C rise, the albedo will drop by 2%*2/3 = 4/3%. However this will mainly happen in northern and southern latitudes, around 60 degrees off the equator, and so the effective area is actually 2% * cos(60 o ) = 1%, and the global albedo drop would be 2/3%.
Diffuse reflection on sphere and flat disk, each for the case of a geometric albedo of 1. For the hypothetical case of a plane surface, the geometric albedo is the albedo of the surface when the illumination is provided by a beam of radiation that comes in perpendicular to the surface.
The planet has an albedo that depends on the characteristics of its surface and atmosphere, and therefore only absorbs a fraction of radiation. The planet absorbs the radiation that isn't reflected by the albedo, and heats up. One may assume that the planet radiates energy like a blackbody at some temperature according to the Stefan–Boltzmann ...
Quantity (common name/s) (Common) symbol/s Defining equation SI unit Dimension Temperature gradient: No standard symbol K⋅m −1: ΘL −1: Thermal conduction rate, thermal current, thermal/heat flux, thermal power transfer
[12] [13] When the body appears white, it is emitting a substantial fraction of its energy as ultraviolet radiation. The Sun , with an effective temperature of approximately 5800 K, [ 14 ] is an approximate black body with an emission spectrum peaked in the central, yellow-green part of the visible spectrum , but with significant power in the ...