<descriptor thcode="2"><thesaurus thcode="2" name="USGS Thesaurus" scope="Topics and methods of scientific study carried out by USGS, with product types, scientific disciplines, geologic time, and types of institutional structure and activities.  Broad and shallow, used to help people find scientific information." creator="U.S. Geological Survey" rights="Public domain" edition="2.0" date="2020-01-09" codetype="number" prefix="topic" uri="https://www2.usgs.gov/science/USGSThesaurus" tblname="term" nonpref="nonpref" relterm="relterm" root_code="1" contact="pschweitzer"><category><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/></category><altlabel><altlabel>USGSThesaurus</altlabel><altlabel>USGSThesaurus</altlabel></altlabel></thesaurus><term thcode="2" code="818" name="ocean sciences" parent="291" scope="Sciences involved in the study of geological, biological, chemical, and physical characteristics and processes of the oceans."/><uf><usefor name="oceanography"/><usefor name="physical oceanography"/></uf><bt><term thcode="2" code="291" name="earth sciences" parent="1019" scope="Broad term for all science related to the study of the earth."/><term thcode="2" code="1019" name="sciences" parent="1" scope="Major educational fields, fields of study, and professional groupings within USGS."/><term thcode="2" code="1" name="Categories" scope="Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."/></bt><nt><term thcode="2" code="859" name="paleoceanography" parent="818" scope="Study of the oceans in the geologic past, including their physical, chemical, biologic, and geologic history."/></nt><rt><term thcode="2" code="222" name="CTD measurement" parent="375" scope="Instrumental determination of conductivity, temperature, and pressure as a function of depth to determine the salinity of seawater."/><term thcode="2" code="80" name="bathymetry" parent="1176" scope="The elevation of the earth's surface beneath a body of water, especially the ocean, typically determined by measurements of depth from the water surface."/><term thcode="2" code="485" name="effects of climate change" parent="1174" scope="Characteristics and behaviors of organisms and earth systems that are modified as a result of changes in global, regional, or local climate."/><term thcode="2" code="560" name="hydrology" parent="291" scope="Branch of earth science that deals with water as it occurs in the atmosphere, on the surface of the ground, and underground."/><term thcode="2" code="702" name="marine biology" parent="650" scope="Branch of biology concerned with the organisms and habitats of the seas and oceans."/><term thcode="2" code="703" name="marine chemistry" parent="1298" scope="Branch of chemistry that deals with the properties, composition, structure, and interaction of substances in the seas and oceans."/><term thcode="2" code="706" name="marine geology" parent="464" scope="Branch of geology concerned with the composition, geologic history, and earth processes of the ocean floor and the continental margin."/><term thcode="2" code="707" name="marine geophysics" parent="470" scope="Branch of earth sciences concerned with the physical processes of the oceans and continental margins.  We include here studies of large bodies of brackish and fresh water, such as lakes and rivers."/><term thcode="2" code="708" name="marine water quality" parent="1306" scope="Observed intrinsic characteristics of marine waters affecting their ability to support life or facilitate biological processes such as waste decomposition."/><term thcode="2" code="731" name="meteorology" parent="68" scope="Branch of science dealing with the short-term variations of atmospheric conditions including wind, precipitation, temperature, humidity, cloud cover, and air pressure."/><term thcode="2" code="810" name="ocean characteristics" parent="287" scope="The attributes and process of seas and oceans."/><term thcode="2" code="812" name="ocean circulation" parent="816" scope="Movement of large masses of water within an ocean."/><term thcode="2" code="814" name="ocean currents" parent="816" scope="Recurrent strong flows of seawater generated by wind or variations in water density along a given path."/><term thcode="2" code="816" name="ocean processes" parent="101" scope="Recurrent natural changes that are physical, biological, or chemical, actively affecting the seas and oceans."/><term thcode="2" code="817" name="ocean salinity" parent="810" scope="Measure of the percentage of dissolved salts in seawater."/><term thcode="2" code="819" name="ocean temperature" parent="810" scope="Distribution of heat in the oceans, including surface water, thermocline and mode waters, and deep waters.  Includes discussion and measures of both in-situ and potential temperature."/><term thcode="2" code="822" name="ocean waves" parent="816" scope="A periodic movement of seawater caused by wind, tide, and currents."/><term thcode="2" code="823" name="ocean-atmosphere interaction" parent="63" scope="Processes, including momentum, heat, gas and other exchanges, which result in profound effects on climate and interactions between the air in the lowest part of the atmosphere and the oceans."/><term thcode="2" code="1025" name="sea-floor characteristics" parent="810" scope="Geomorphic features and geographic, compositional, and textural variation in the materials composing the ocean floor. Includes both large-scale structures (such as seamounts and rises) and fine-scale variations in rocks and deposits on the sea floor."/><term thcode="2" code="1028" name="sea-level change" parent="810" scope="Variation in the relative vertical position of land and ocean waters. Caused globally by changes in the distribution of ice masses and the shape of the oceans, and locally by the rate of uplift or subsidence of the land surface.  Includes both global (eustatic) and local (relative) sea-level variations."/><term thcode="2" code="1168" name="tides (oceanic)" parent="816" scope="The periodic rise and fall of the level of the sea due to the gravitational attraction of the moon and sun. Occurs twice each day."/><term thcode="2" code="1195" name="tsunamis" parent="822" scope="Sea waves generated by submarine earthquakes, volcanic eruptions, or landslides, which are generally imperceptible in deep water but may be very destructive when striking the shoreline."/><term thcode="2" code="1201" name="underwater photography" parent="889" scope="Photographs taken below the water surface, usually in marine, lacustrine, and estuarine environments.  Subjects are typically benthic organisms and sedimentary structures on the bottom."/></rt></descriptor>