Physical Geography Terms

1) Albedo (Al-bee-dough): of an object is the extent to which it diffusely reflects light from the Sun(reflectivity). Albedo is defined as the ratio of diffusely reflected to incident electromagnetic radiation. It is a unitless measure indicative of a surface's or body's diffuse reflectivity. The word is derived from Latin albedo "whiteness", in turn from albus "white". The range of possible values is from 0 (dark) to 1 (bright). Percentage of diffusely reflected sun light in relation to various surface conditions of the EarthThe albedo is an important concept in climatology and astronomy. In climatology it is sometimes expressed as a percentage. Its value depends on the frequency of radiation considered: unqualified, it usually refers to some appropriate average across the spectrum of visible light. In general, the albedo depends on the direction and directional distribution of incoming radiation. Exceptions are Lambertian surfaces, which scatter radiation in all directions in a cosine function, so their albedo does not depend on the incoming distribution. In realistic cases, a bidirectional reflectance distribution function (BRDF) is required to characterize the scattering properties of a surface accurately, although albedos are a very useful first approximation.

2) EQUATOR: The equator (sometimes referred to colloquially as "the Line") is the intersection of the Earth's surface with the plane perpendicular to the Earth's axis of rotation and containing the Earth's center of mass. It's located at zero degrees latitude, an imaginary line on the Earth's surface approximately equidistant from the North Pole and South pole that divides the Earth into a North and South Hemisphere.

3) Tropics of Cancer and Capricorn: Located at 23.5 degrees North and 23.5 degrees South of the Equator, this area of Planet Earth (between those two lines) is known as the "Tropics,". This area experiences no dramatic change in season because the sun is consistently high in the sky throughout the year. People living North of the Tropic of Cancer and South of the Tropic of Capricorn experience dramatic seasonal climate changes, based on the earth's tilt, and the subsequent angle of the sun. When it's summer North of the Tropic of Cancer, it's winter South of the Tropic of Capricorn. (The reverse is also true).

4) Prime Meridian: Located at zero degrees longitude (East or West), it divides the Planet Earth into the Eastern and Western Hemispheres and is the line from which all other lines of longitude are measured.

5) Crust: The crust covers the mantle and is the earth's hard outer shell, the surface on which we are living. Compared to the other layers the crust is much thinner. It floats upon the softer, denser mantle. The crust is made up of solid material but this material is not the same everywhere. There is an Oceanic crust and a Continental crust. The first one is about 4-7 miles (6-11 km) thick and mainly consists of heavy rocks, like basalt. The Continental crust is thicker than the Oceanic crust, about 19 miles(30 km) thick. It is mainly made up of light material like granite.

For more info goto http://mediatheek.thinkquest.nl/~ll125/en/crust.htm

6) Layers of the Earth's Atmosphere:

The atmosphere is divided into five layers.
It is thickest near the surface and thins out with height until it eventually merges with space.

1) The troposhere is the first layer above the surface and contains half of the Earth's atmosphere. Weather occurs in this layer.
2) Many jet aircrafts fly in thestratosphere because it is very stable. Also, the ozone layer absorbs harmful rays from the Sun.
3) Meteors or rock fragments burn up in the mesophere.
4) The thermosphere is a layer with auroras. It is also where the space shuttle orbits.
5) The atmosphere merges into space in the extremely thin exosphere. This is the upper limit of our atmosphere.

Explanation:
ionosphere=aayonmandal
exosphere=vahirmandal
mesosphere=antarmandal
troposphere=skobhmandal
stratosphere=samataapmandal

More info goto: http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.html

or http://www.vtaide.com/png/atmosphere.htm
or http://www.windows.ucar.edu/tour/link=/earth/Atmosphere/layers.html