Search results
Results from the WOW.Com Content Network
Just as fresh snow has a higher albedo than does dirty snow, the albedo of snow-covered sea ice is far higher than that of sea water. Sea water absorbs more solar radiation than would the same surface covered with reflective snow. When sea ice melts, either due to a rise in sea temperature or in response to increased solar radiation from above ...
Albedo change in Greenland from 2000-2006 to 2011. Practically the entire ice sheet became less reflective. Snow– and ice–albedo feedback have a substantial effect on regional temperatures. In particular, the presence of ice cover and sea ice makes the North Pole and the South Pole colder than they would have been without it. [4]
The initiation of a snowball Earth event would involve some initial cooling mechanism, which would result in an increase in Earth's coverage of snow and ice. The increase in Earth's coverage of snow and ice would in turn increase Earth's albedo, which would result in positive feedback for cooling.
Typically, albedo values for non-melting snow-covered surfaces are high (~80–90%) except in the case of forests. [ citation needed ] The higher albedos for snow and ice cause rapid shifts in surface reflectivity in autumn and spring in high latitudes, but the overall climatic significance of this increase is spatially and temporally modulated ...
Sea ice is highly reflective of solar radiation, reflecting about 60% of incoming solar radiation when bare and about 80% when covered with snow. This is due to a feedback known as the albedo effect. [3] This is much greater than the reflectivity of the sea (about 10%) and thus the ice also affects the absorption of sunlight at the surface. [4] [5]
Called the albedo of Earth, around 35 units in this example are directly reflected back to space: 27 from the top of clouds, 2 from snow and ice-covered areas, and 6 by other parts of the atmosphere. The 65 remaining units (ASR = 220 W/m 2) are absorbed: 14 within the atmosphere and 51 by the Earth's surface.
The rate of glacier melt depends on the surface albedo. Recent research has shown the growth of snow and glacier ice algae darkens local surface conditions, decreasing the albedo and thus increases the melt rate on these surfaces. [46] [45] [47] Melting glaciers and ice sheets have been directly linked to increase in sea level rise. [48]
The downward facing pyranometer measures the reflected global solar radiation. The ratio of the reflected to the global radiation is the solar albedo and depends on the properties of the surface and the directional distribution of the incoming solar radiation. Typical values range from 4% [2] for asphalt to 90% [3] for fresh snow.