When scientists talk about the cryosphere, they mean the places on Earth where water is in its solid form, frozen into ice or snow. Read more ...
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climatology and meteorology
the boundary layer between the troposphere and stratosphere, where an abrupt change in temperature lapse rate usually occurs; it is defined as the lowest level at which the lapse rate decreases to 2 degrees Celsius per kilometer or less, provided that the average lapse rate between this level and all higher levels within 2 kilometers does not exceed 2 degrees Celsius per kilometer; occasionally, a second tropopause may be found if the lapse rate above the first tropopause exceeds 3 degrees Celsius per kilometer.
the southern parallel of maximum solar declination, approximately 23° 27′ S latitude; the farthest southern latitude at which the sun can appear directly overhead, which occurs on the day of the summer solstice.
the northern parallel of maximum solar declination, approximately 23° 27′ N latitude; the farthest northern latitude at which the sun can appear directly overhead, which occurs on the day of the summer solstice.