{"thcode":2,"term":{"code":856,"name":"ozone layer","parent":65,"scope":"Upper atmosphere layer composed of ozone, a gas made up of molecules comprised of three oxygen atoms, which helps to shield the earth from ultraviolet rays."},"uf":[{"name":"ozonesphere","usewith":false}],"bt":[{"code":65,"name":"atmospheric composition","parent":67,"scope":"Components of the mass of gases that surrounds a planet.  The earth's atmosphere consists of nitrogen, oxygen, and small portions of other gases."},{"code":67,"name":"atmospheric properties","parent":287,"scope":"Characteristics of the mass of gases surrounding the earth  such as composition, temperature, pressure, and humidity."},{"code":287,"name":"earth characteristics","parent":1174,"scope":"The measurable, definable properties and features of the earth."},{"code":1174,"name":"topics","parent":1,"scope":"Themes, subjects, and concerns for which USGS information resources are relevant."},{"code":1,"name":"Categories","parent":null,"scope":"Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."}],"nt":[],"rt":[{"code":68,"name":"atmospheric sciences","parent":291,"scope":"Studies relating to composition, structure, physics, chemistry, and dynamics of the atmosphere."},{"code":506,"name":"greenhouse gases","parent":65,"scope":"Atmospheric gases, including carbon dioxide, fluorocarbons, methane, nitrous oxide, sulfur hexafluoride, ozone, and water vapor, that trap radiant (infrared) energy keeping the earth's surface warmer than it would otherwise be."}]}