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AGU Index Terms 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE 0305 Aerosols and particles (0345, 4801, 4906) 0310 Airglow and aurora 0312 Air/sea constituent fluxes (3339, 4504) 0315 Biosphere/atmosphere interactions (0426, 1610) 0317 Chemical kinetic and photochemical properties 0319 Cloud optics 0320 Cloud physics and chemistry 0321 Cloud/radiation interaction 0322 Constituent sources and sinks 0325 Evolution of the atmosphere (1610, 8125) 0328 Exosphere 0330 Geochemical cycles (1030) 0335 Ion chemistry of the atmosphere (2419, 2427) 0340 Middle atmosphere: composition and chemistry 0341 Middle atmosphere: constituent transport and chemistry (3334) 0342 Middle atmosphere: energy deposition (3334) 0343 Planetary atmospheres (5210, 5405, 5704) 0345 Pollution: urban and regional (0305, 0478, 4251, 4325) 0350 Pressure, density, and temperature 0355 Thermosphere: composition and chemistry 0358 Thermosphere: energy deposition (3369) 0360 Radiation: transmission and scattering 0365 Troposphere: composition and chemistry 0368 Troposphere: constituent transport and chemistry 0370 Volcanic effects (4301, 8409) 0394 Instruments and techniques 0399 General or miscellaneous 0400 BIOGEOSCIENCES 0402 Agricultural systems 0404 Anoxic and hypoxic environments (4802, 4834) 0406 Astrobiology and extraterrestrial materials 0408 Benthic processes (4804) 0409 Bioavailability: chemical speciation and complexation 0410 Biodiversity 0412 Biogeochemical kinetics and reaction modeling (0414, 0793, 1615, 4805, 4912) 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912) 0416 Biogeophysics 0418 Bioremediation 0419 Biomineralization 0420 Biomolecular and chemical tracers 0422 Bio-optics 0424 Biosignatures and proxies 0426 Biosphere/atmosphere interactions (0315) 0428 Carbon cycling (4806) 0429 Climate dynamics (1620) 0430 Computational methods and data processing 0432 Contaminant and organic biogeochemistry (0792) 0434 Data sets 0438 Diel, seasonal, and annual cycles (4227) 0439 Ecosystems, structure and dynamics (4815) 0442 Estuarine and nearshore processes (4235) 0444 Evolutionary geobiology 0448 Geomicrobiology 0450 Hydrothermal systems (1034, 3017, 3616, 4832, 8135, 8424) 0452 Instruments and techniques 0454 Isotopic composition and chemistry (1041, 4870) 0456 Life in extreme environments 0458 Limnology (1845, 4239, 4942) 0459 Macro- and micropaleontology (3030, 4944) 0460 Marine systems (4800) 0461 Metals 0463 Microbe/mineral interactions 0465 Microbiology: ecology, physiology and genomics (4840) 0466 Modeling (1952, 4316) 0468 Natural hazards (4308) 0469 Nitrogen cycling 0470 Nutrients and nutrient cycling (4845, 4850) 0471 Oxidation/reduction reactions (4851) 0473 Paleoclimatology and paleoceanography (3344, 4900) 0475 Permafrost, cryosphere, and high-latitude processes (0702, 0716) 0476 Plant ecology (1851) 0478 Pollution: urban, regional and global (0345, 4251, 4325) 0480 Remote sensing 0481 Restoration 0483 Riparian systems (0744, 1856) 0485 Science policy (6620) 0486 Soils/pedology (1865) 0488 Sulfur cycling 0489 Trace element cycling (4875) 0490 Trace gases 0491 Food webs and trophodynamics (4817) 0493 Urban systems (4325) 0495 Water/energy interactions (1878) 0496 Water quality 0497 Wetlands (1890) 0498 General or miscellaneous 0499 New fields (not classifiable under other headings) 0500 COMPUTATIONAL GEOPHYSICS (1980, 3200, 3252, 4307, 4314, 7833) 0510 Agent-based models 0515 Cellular automata 0520 Data analysis: algorithms and implementation 0525 Data management 0530 Data presentation and visualization (1994) 0535 Hardware solutions 0540 Image processing 0545 Modeling (1952, 4255, 4316) 0550 Model verification and validation 0555 Neural networks, fuzzy logic, machine learning (1942) 0560 Numerical solutions (4255) 0594 Instruments and techniques 0599 General or miscellaneous 0700 CRYOSPHERE (4540) 0702 Permafrost (0475, 4308) 0704 Seasonally frozen ground 0706 Active layer 0708 Thermokarst 0710 Periglacial processes 0712 Cryosol 0714 Clathrate 0716 Cryobiology (0475) 0718 Tundra (9315) 0720 Glaciers 0722 Rock glaciers 0724 Ice cores (4932) 0726 Ice sheets 0728 Ice shelves 0730 Ice streams 0732 Icebergs 0734 Icing (aufeis, naled) 0736 Snow (1827, 1863) 0738 Ice (1863) 0740 Snowmelt 0742 Avalanches (4302) 0744 Rivers (0483, 1856) 0746 Lakes (9345) 0748 Ponds 0750 Sea ice (4540) 0752 Polynas (4540) 0754 Leads (4540) 0758 Remote sensing 0760 Engineering 0762 Mass balance (1218, 1223) 0764 Energy balance 0766 Thermodynamics (1011, 3611, 8411) 0768 Thermal regime 0770 Properties 0772 Distribution 0774 Dynamics 0776 Glaciology (1621, 1827, 1863) 0790 Weathering (1625, 1886) 0792 Contaminants (0432) 0793 Biogeochemistry (0412, 0414, 1615, 4805, 4912) 0794 Instruments and techniques 0798 Modeling (1952, 4316) 0799 General or miscellaneous 0800 EDUCATION 0805 Elementary and secondary education 0810 Post-secondary education 0815 Informal education 0820 Curriculum and laboratory design 0825 Teaching methods 0830 Teacher training 0840 Evaluation and assessment 0845 Instructional tools 0850 Geoscience education research 0855 Diversity 0600 ELECTROMAGNETICS 0604 Antenna arrays 0609 Antennas 0614 Biological effects 0619 Electromagnetic theory 0624 Guided waves 0629 Inverse scattering 0634 Measurement and standards 0639 Nonlinear electromagnetics 0644 Numerical methods 0649 Optics (4264) 0654 Plasmas 0659 Random media and rough surfaces 0664 Reflectors and feeds 0669 Scattering and diffraction 0674 Signal processing and adaptive antennas (6974) 0679 Singularity expansion method 0684 Transient and time domain 0689 Wave propagation (2487, 3285, 4275, 4455, 6934) 0694 Instruments and techniques 0699 General or miscellaneous 0900 EXPLORATION GEOPHYSICS 0902 Computational methods: seismic 0903 Computational methods: potential fields (1214) 0905 Continental structures (8109, 8110) 0910 Data processing 0915 Downhole methods 0920 Gravity methods (1219) 0925 Magnetic and electrical methods (5109) 0930 Oceanic structures 0932 Radioactivity methods 0933 Remote sensing 0935 Seismic methods (3025, 7294) 0994 Instruments and techniques 0999 General or miscellaneous 1000 GEOCHEMISTRY 1009 Geochemical modeling (3610, 8410) 1011 Thermodynamics (0766, 3611, 8411) 1012 Reactions and phase equilibria (3612, 8412) 1031 Subduction zone processes (3060, 3613, 8170, 8413) 1032 Mid-oceanic ridge processes (3614, 8416) 1033 Intra-plate processes (3615, 8415) 1034 Hydrothermal systems (0450, 3017, 3616, 4832, 8135, 8424) 1039 Alteration and weathering processes (3617) 1036 Magma chamber processes (3618) 1037 Magma genesis and partial melting (3619) 1038 Mantle processes (3621) 1015 Composition of the core 1020 Composition of the continental crust 1021 Composition of the oceanic crust 1022 Composition of the hydrosphere 1023 Composition of the biosphere 1025 Composition of the mantle 1026 Composition of the moon 1027 Composition of the planets 1028 Composition of meteorites (3662, 6240) 1029 Composition of aerosols and dust particles 1030 Geochemical cycles (0330) 1065 Major and trace element geochemistry 1040 Radiogenic isotope geochemistry 1041 Stable isotope geochemistry (0454, 4870) 1042 Mineral and crystal chemistry (3620) 1043 Fluid and melt inclusion geochemistry 1050 Marine geochemistry (4835, 4845, 4850) 1051 Sedimentary geochemistry 1055 Organic and biogenic geochemistry 1060 Planetary geochemistry (5405, 5410, 5704, 5709, 6005, 6008) 1090 Field relationships (3690, 8486) 1094 Instruments and techniques 1099 General or miscellaneous 1100 GEOCHRONOLOGY 1105 Quaternary geochronology 1110 Sidereal geochronology 1115 Radioisotope geochronology 1120 Isotopic disequilibrium dating 1125 Chemical and biological geochronology 1130 Geomorphological geochronology 1135 Correlative geochronology 1140 Thermochronology 1145 Tephrochronology (8455) 1150 Cosmogenic-nuclide exposure dating (4918) 1155 Extinct radionuclide geochronology 1160 Planetary and lunar geochronology 1165 Sedimentary geochronology 1194 Instruments and techniques 1199 General or miscellaneous 1200 GEODESY AND GRAVITY 1244 Standards and absolute measurements 1294 Instruments and techniques 1295 Integrations of techniques 1240 Satellite geodesy: results (6929, 7215, 7230, 7240) 1241 Satellite geodesy: technical issues (6994, 7969) 1243 Space geodetic surveys(4337) 1204 Control surveys 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230) 1207 Transient deformation (6924, 7230, 7240) 1209 Tectonic deformation (6924) 1211 Non-tectonic deformation 1212 Earth's interior: composition and state (7207, 7208, 8105, 8124) 1213 Earth's interior: dynamics (1507, 7207, 7208, 8115, 8120) 1236 Rheology of the lithosphere and mantle (7218, 8160) 1219 Gravity anomalies and Earth structure (0920, 7205, 7240) 1214 Geopotential theory and determination (0903) 1217 Time variable gravity (7223, 7230) 1229 Reference systems 1239 Earth rotation variations 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550) 1218 Mass balance (0762, 1223, 1631, 1836, 1843, 3010, 3322, 4532) 1220 Atmosphere monitoring with geodetic techniques (6952) 1222 Ocean monitoring with geodetic techniques (1225, 1641, 3010, 4532, 4556, 4560, 6959) 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556) 1221 Lunar and planetary geodesy and gravity (5417, 5450, 5714, 5744, 6019, 6250) 1299 General or miscellaneous (1709) 1500 GEOMAGNETISM AND PALEOMAGNETISM 1503 Archeomagnetism 1505 Biogenic magnetic minerals 1507 Core processes (1213, 8115) 1510 Dynamo: theories and simulations 1512 Environmental magnetism 1513 Geomagnetic excursions 1515 Geomagnetic induction 1517 Magnetic anomalies: modeling and interpretation 1518 Magnetic fabrics and anisotropy 1519 Magnetic mineralogy and petrology 1520 Magnetostratigraphy 1521 Paleointensity 1522 Paleomagnetic secular variation 1525 Paleomagnetism applied to tectonics: regional, global 1527 Paleomagnetism applied to geologic processes 1530 Rapid time variations 1532 Reference fields: regional, global 1533 Remagnetization 1535 Reversals: process, timescale, magnetostratigraphy 1540 Rock and mineral magnetism 1541 Satellite magnetics: main field, crustal field, external field 1545 Spatial variations: all harmonics and anomalies 1550 Spatial variations attributed to seafloor spreading (3005) 1555 Time variations: diurnal to decadal 1560 Time variations: secular and longer 1594 Instruments and techniques 1595 Planetary magnetism: all frequencies and wavelengths 1599 General or miscellaneous 1600 GLOBAL CHANGE 1605 Abrupt/rapid climate change (4901, 8408) 1610 Atmosphere (0315, 0325) 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912) 1616 Climate variability (1635, 3305, 3309, 4215, 4513) 1620 Climate dynamics (0429, 3309) 1621 Cryospheric change (0776) 1622 Earth system modeling (1225, 4316) 1625 Geomorphology and weathering (0790, 1824, 1825, 1826, 1886) 1626 Global climate models (3337, 4928) 1627 Coupled models of the climate system 1630 Impacts of global change (1225, 4321) 1631 Land/atmosphere interactions (1218, 1843, 3322) 1632 Land cover change 1635 Oceans (1616, 3305, 4215, 4513) 1637 Regional climate change (4321) 1640 Remote sensing (1855, 4337) 1641 Sea level change (1222, 1225, 4304, 4556) 1645 Solid Earth (1225) 1650 Solar variability (7537) 1655 Water cycles (1836) 1694 Instruments and techniques 1699 General or miscellaneous 1700 HISTORY OF GEOPHYSICS 1704 Atmospheric sciences 1705 Biogeosciences 1706 Computational geophysics 1707 Cryosphere 1708 Geochronology 1709 Geodesy (1299) 1714 Geomagnetism and paleomagnetism 1719 Hydrology 1721 Nonlinear geophysics 1724 Ocean sciences 1729 Planetology 1734 Seismology 1739 Solar/planetary relationships 1744 Tectonophysics 1749 Volcanology, geochemistry, and petrology 1794 Instruments and techniques 1799 General or miscellaneous 1800 HYDROLOGY 1803 Anthropogenic effects (4802, 4902) 1804 Catchment 1806 Chemistry of fresh water 1807 Climate impacts (4321) 1805 Computational hydrology 1808 Dams 1810 Debris flow and landslides (4303) 1809 Desertification 1812 Drought (4303) 1813 Eco-hydrology 1814 Energy budgets 1815 Erosion 1816 Estimation and forecasting (4315) 1818 Evapotranspiration 1817 Extreme events (4313) 1821 Floods (4303) 1820 Floodplain dynamics 1823 Frozen ground 1819 Geographic Information Systems (GIS) 1822 Geomechanics 1824 Geomorphology: general (1625) 1825 Geomorphology: fluvial (1625) 1826 Geomorphology: hillslope (1625) 1827 Glaciology (0736, 0776, 1863) 1828 Groundwater hydraulics 1829 Groundwater hydrology 1831 Groundwater quality 1830 Groundwater/surface water interaction 1832 Groundwater transport 1834 Human impacts (4323) 1833 Hydroclimatology 1835 Hydrogeophysics 1836 Hydrological cycles and budgets (1218, 1655) 1840 Hydrometeorology 1839 Hydrologic scaling 1838 Infiltration 1842 Irrigation 1843 Land/atmosphere interactions (1218, 1631, 3322) 1845 Limnology (0458, 4239, 4942) 1846 Model calibration (3333) 1847 Modeling (1952, 4316) 1848 Monitoring networks 1849 Numerical approximations and analysis (3336) 1850 Overland flow 1851 Plant ecology (0476) 1852 Plant uptake 1854 Precipitation (3354) 1853 Precipitation-radar 1855 Remote sensing (1640, 4337) 1857 Reservoirs (surface) 1856 River channels (0483, 0744) 1858 Rocks: chemical properties 1859 Rocks: physical properties 1860 Streamflow 1861 Sedimentation (4863) 1862 Sediment transport (4558) 1863 Snow and ice (0736, 0738, 0776, 1827) 1865 Soils (0486) 1866 Soil moisture 1869 Stochastic hydrology 1871 Surface water quality 1872 Time series analysis (1988, 3270, 4277, 4475) 1873 Uncertainty assessment (1990, 3275) 1874 Ungaged basins 1875 Vadose zone 1876 Water budgets 1878 Water/energy interactions (0495) 1879 Watershed 1880 Water management (6334) 1884 Water supply 1886 Weathering (0790, 1625) 1890 Wetlands (0497) 1894 Instruments and techniques: modeling 1895 Instruments and techniques: monitoring 1899 General or miscellaneous 1900 INFORMATICS 1902 Community modeling frameworks 1904 Community standards 1906 Computational models, algorithms 1908 Cyberinfrastructure 1910 Data assimilation, integration and fusion 1912 Data management, preservation, rescue 1914 Data mining 1916 Data and information discovery 1918 Decision analysis (4324, 6309) 1920 Emerging informatics technologies 1922 Forecasting (2722, 4315, 7924) 1924 Formal logics and grammars 1926 Geospatial 1928 GIS science 1930 Data and information governance 1932 High-performance computing 1934 International collaboration 1936 Interoperability 1938 Knowledge representation and knowledge bases 1940 Machine-to-machine communication 1942 Machine learning (0555) 1944 Markup languages 1946 Metadata 1948 Metadata: Provenance 1950 Metadata: Quality 1952 Modeling (0466, 0545, 0798, 1847, 4255, 4316) 1954 Natural language processing 1956 Numerical algorithms 1958 Ontologies 1960 Portals and user interfaces 1962 Query languages for science, markup languages, ontologies 1964 Real-time and responsive information delivery (4346) 1966 Rules and logic 1968 Scientific reasoning/inference 1970 Semantic web and semantic integration 1972 Sensor web 1974 Social networks 1976 Software tools and services 1978 Software re-use 1980 Spatial analysis and representation (0500, 3252) 1982 Standards 1984 Statistical methods: Descriptive (4318) 1986 Statistical methods: Inferential (4318) 1988 Temporal analysis and representation (1872, 3270, 4277, 4475) 1990 Uncertainty (1873, 3275) 1992 Virtual globes 1994 Visualization and portrayal (0530) 1996 Web Services 1998 Workflow 1999 General or miscellaneous 2100 INTERPLANETARY PHYSICS 2101 Coronal mass ejections (4305, 7513) 2102 Corotating streams 2104 Cosmic rays 2109 Discontinuities (7811) 2111 Ejecta, driver gases, and magnetic clouds 2114 Energetic particles (7514) 2124 Heliopause and solar wind termination 2126 Heliosphere/interstellar medium interactions 2129 Interplanetary dust 2134 Interplanetary magnetic fields 2139 Interplanetary shocks 2144 Interstellar gas 2149 MHD waves and turbulence (2752, 6050, 7836) 2151 Neutral particles (7837) 2152 Pickup ions 2154 Planetary bow shocks 2159 Plasma waves and turbulence 2162 Solar cycle variations (7536) 2164 Solar wind plasma 2169 Solar wind sources 2194 Instruments and techniques 2199 General or miscellaneous 2400 IONOSPHERE (6929) 2403 Active experiments 2407 Auroral ionosphere (2704) 2409 Current systems (2721) 2411 Electric fields (2712) 2415 Equatorial ionosphere 2419 Ion chemistry and composition (0335) 2423 Ionization processes (7823) 2427 Ionosphere/atmosphere interactions (0335) 2431 Ionosphere/magnetosphere interactions (2736) 2435 Ionospheric disturbances 2437 Ionospheric dynamics 2439 Ionospheric irregularities 2441 Ionospheric storms (7949) 2442 Meteor-trail physics 2443 Midlatitude ionosphere 2447 Modeling and forecasting 2451 Particle acceleration 2455 Particle precipitation 2459 Planetary ionospheres (5435, 5729, 6026) 2461 Plasma interactions with dust and aerosols (7849) 2463 Plasma convection (2760) 2467 Plasma temperature and density 2471 Plasma waves and instabilities (2772) 2475 Polar cap ionosphere 2479 Solar radiation and cosmic ray effects 2481 Topside ionosphere 2483 Wave/particle interactions (7867) 2487 Wave propagation (0689, 3285, 4275, 4455, 6934) 2494 Instruments and techniques 2499 General or miscellaneous 2700 MAGNETOSPHERIC PHYSICS (6939) 2704 Auroral phenomena (2407) 2706 Cusp 2712 Electric fields (2411) 2716 Energetic particles: precipitating 2720 Energetic particles: trapped 2721 Field-aligned currents and current systems (2409) 2722 Forecasting (1922, 4315, 7924, 7964) 2723 Magnetic reconnection (7526, 7835) 2724 Magnetopause and boundary layers 2728 Magnetosheath 2730 Magnetosphere: inner 2731 Magnetosphere: outer 2732 Magnetosphere interactions with satellites and rings 2736 Magnetosphere/ionosphere interactions (2431) 2740 Magnetospheric configuration and dynamics 2744 Magnetotail 2748 Magnetotail boundary layers 2752 MHD waves and instabilities (2149, 6050, 7836) 2753 Numerical modeling 2756 Planetary magnetospheres (5443, 5737, 6033) 2760 Plasma convection (2463) 2764 Plasma sheet 2768 Plasmasphere 2772 Plasma waves and instabilities (2471) 2776 Polar cap phenomena 2774 Radiation belts 2778 Ring current 2780 Solar wind interactions with unmagnetized bodies 2784 Solar wind/magnetosphere interactions 2788 Magnetic storms and substorms (4305, 7954) 2790 Substorms 2794 Instruments and techniques 2799 General or miscellaneous 3000 MARINE GEOLOGY AND GEOPHYSICS 3001 Back-arc basin processes 3002 Continental shelf and slope processes (4219) 3004 Gas and hydrate systems 3005 Marine magnetics and paleomagnetics (1550) 3006 Marine electromagnetics 3010 Gravity and isostasy (1218, 1222) 3015 Heat flow (benthic) 3017 Hydrothermal systems (0450, 1034, 3616, 4832, 8135, 8424) 3020 Littoral processes 3021 Marine hydrogeology 3022 Marine sediments: processes and transport 3025 Marine seismics (0935, 7294) 3030 Micropaleontology (0459, 4944) 3035 Midocean ridge processes 3036 Ocean drilling 3037 Oceanic hotspots and intraplate volcanism 3038 Oceanic plateaus and microcontinents 3039 Oceanic transform and fracture zone processes 3040 Plate tectonics (8150, 8155, 8157, 8158) 3042 Ophiolites (8140) 3045 Seafloor morphology, geology, and geophysics 3050 Ocean observatories and experiments 3060 Subduction zone processes (1031, 3613, 8170, 8413) 3070 Submarine landslides 3075 Submarine tectonics and volcanism 3080 Submergence instruments: ROV, AUV, submersibles 3094 Instruments and techniques 3099 General or miscellaneous 3200 MATHEMATICAL GEOPHYSICS (0500, 4307, 4314, 4400, 7833) 3205 Fourier analysis (3255) 3215 Instability analysis (4312) 3260 Inverse theory 3225 Numerical approximations and analysis (4260) 3235 Persistence, memory, correlations, clustering (3265, 4313, 7857) 3238 Prediction (3245, 4263, 4315) 3245 Probabilistic forecasting (3238, 4315) 3252 Spatial analysis (0500, 1980, 4319) 3255 Spectral analysis (3205, 3280, 4319) 3265 Stochastic processes (3235, 4468, 4475, 7857) 3270 Time series analysis (1872, 1988, 4277, 4475) 3275 Uncertainty quantification (1873, 1990) 3280 Wavelet transform (3255, 4455) 3285 Wave propagation (0689, 2487, 4275, 4455, 6934) 3294 Instruments and techniques 3299 General or miscellaneous 3300 ATMOSPHERIC PROCESSES 3304 Atmospheric electricity 3303 Balanced dynamical models 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513) 3307 Boundary layer processes 3309 Climatology (1616, 1620, 3305, 4215, 8408) 3311 Clouds and aerosols 3310 Clouds and cloud feedbacks 3314 Convective processes 3315 Data assimilation 3319 General circulation (1223) 3320 Idealized model 3322 Land/atmosphere interactions (1218, 1631, 1843, 4301) 3323 Large eddy simulation 3324 Lightning 3325 Monte Carlo technique 3329 Mesoscale meteorology 3332 Mesospheric dynamics 3333 Model calibration (1846) 3334 Middle atmosphere dynamics (0341, 0342) 3335 North American Monsoon 3336 Numerical approximations and analyses (1849) 3337 Global climate models (1626, 4928) 3339 Ocean/atmosphere interactions (0312, 4301, 4504) 3344 Paleoclimatology (0473, 4900) 3346 Planetary meteorology (5445, 5739) 3349 Polar meteorology 3354 Precipitation (1854) 3359 Radiative processes 3355 Regional modeling (4316) 3360 Remote sensing (4337) 3362 Stratosphere/troposphere interactions 3363 Stratospheric dynamics 3364 Synoptic-scale meteorology 3365 Subgrid-scale (SGS) parameterization 3367 Theoretical modeling (4316) 3369 Thermospheric dynamics (0358) 3371 Tropical convection 3372 Tropical cyclones 3373 Tropical dynamics 3374 Tropical meteorology 3375 Tropopause dynamics 3379 Turbulence (4490) 3384 Acoustic-gravity waves 3389 Tides and planetary waves 3390 Wildland fire model 3394 Instruments and techniques 3399 General or miscellaneous 3600 MINERALOGY AND PETROLOGY 3610 Geochemical modeling (1009, 8410) 3611 Thermodynamics (0766, 1011, 8411) 3612 Reactions and phase equilibria (1012, 8412) 3613 Subduction zone processes (1031, 3060, 8170, 8413) 3614 Mid-oceanic ridge processes (1032, 8416) 3615 Intra-plate processes (1033, 8415) 3616 Hydrothermal systems (0450, 1034, 3017, 4832, 8135, 8424) 3617 Alteration and weathering processes (1039) 3618 Magma chamber processes (1036) 3619 Magma genesis and partial melting (1037) 3621 Mantle processes (1038) 3620 Mineral and crystal chemistry (1042) 3625 Petrography, microstructures, and textures 3630 Experimental mineralogy and petrology 3640 Igneous petrology 3641 Extrusive structures and rocks 3642 Intrusive structures and rocks 3643 Layered magma chambers 3660 Metamorphic petrology 3651 Thermobarometry 3652 Pressure-temperature-time paths 3653 Fluid flow 3654 Ultra-high pressure metamorphism 3656 Ultra-high temperature metamorphism 3662 Meteorite mineralogy and petrology (1028, 6240) 3665 Mineral occurrences and deposits 3672 Planetary mineralogy and petrology (5410) 3675 Sedimentary petrology 3690 Field relationships (1090, 8486) 3694 Instruments and techniques 3699 General or miscellaneous 3900 MINERAL PHYSICS 3902 Creep and deformation 3904 Defects 3909 Elasticity and anelasticity 3914 Electrical properties 3919 Equations of state 3924 High-pressure behavior 3929 NMR, Mossbauer spectroscopy, and other magnetic techniques 3934 Optical, infrared, and Raman spectroscopy 3939 Physical thermodynamics 3944 Shock wave experiments 3947 Surfaces and interfaces 3949 Thermal expansivity 3954 X-ray, neutron, and electron spectroscopy and diffraction 3994 Instruments and techniques 3999 General or miscellaneous 4300 NATURAL HAZARDS 4301 Atmospheric (0370 3322, 3339) 4302 Geological (0742, 4564, 7212, 7280, 8419, 8425, 8426, 8428, 8488) 4303 Hydrological (1810, 1812, 1821) 4304 Oceanic (1641, 4564) 4305 Space weather (2101, 2788, 7900) 4306 Multihazards 4307 Methods (0500, 3200, 4400) 4308 Other (0468, 0702, 6205, 6210) 4311 Analogue modeling 4312 Catastrophe and catastrophe theory (3215) 4313 Extreme events (1817, 3235) 4314 Mathematical and computer modeling (0500, 3200) 4315 Monitoring, forecasting, prediction (1816, 1922, 2722, 3238, 3245, 4263, 7223, 7924) 4316 Physical modeling (0466, 0545, 0798, 1622, 1847, 1952, 3355, 3367) 4317 Precursors 4318 Statistical analysis (1984, 1986) 4319 Spatial modeling (3252, 3255) 4321 Climate impact (1630, 1637, 1807, 8408) 4322 Health impact 4323 Human impact (1834, 7938) 4324 Spatial decision support systems (1918, 6309) 4325 Megacities and urban environment (0345, 0478, 0493) 4326 Exposure 4327 Resilience 4328 Risk (8488) 4329 Sustainable development 4330 Vulnerability 4331 Disaster relief 4332 Disaster resilience 4333 Disaster risk analysis and assessment (6304, 8488) 4334 Disaster risk communication 4335 Disaster management 4336 Economic impacts of disasters 4337 Remote sensing and disasters (1243, 1640, 1855, 3360, 8485) 4338 Disaster policy (6300, 6620) 4339 Disaster mitigation (6309, 7914) 4341 Early warning systems 4342 Emergency management (6344) 4343 Preparedness and planning (6334) 4344 Microzonation and macrozonation 4345 Community management 4346 Emergency response and evacuations (1964) 4347 Recovery and reconstruction after disaster 4348 Contingency planning 4351 International organizations and natural disasters 4352 Interaction between science and disaster management authorities 4353 Sociology of disasters (1974) 4354 Psychology of disasters 4355 Miscellaneous 4400 NONLINEAR GEOPHYSICS (3200, 4307, 6944, 7839) 4410 Bifurcations and attractors 4415 Cascades 4420 Chaos (7805) 4425 Critical phenomena 4430 Complex systems 4435 Emergent phenomena 4440 Fractals and multifractals 4445 Nonlinear differential equations 4450 Nonlinear maps 4455 Nonlinear waves, shock waves, solitons (0689, 2487, 3280, 3285, 4275, 6934, 7851, 7852) 4460 Pattern formation 4465 Phase transitions 4468 Probability distributions, heavy and fat-tailed (3265) 4470 Renormalization group methods 4475 Scaling: spatial and temporal (1872, 1988, 3265, 3270, 4277, 7857) 4480 Self-organized criticality 4485 Self-organization 4490 Turbulence (3379, 4568, 7863) 4494 Instruments and techniques 4499 General or miscellaneous 4200 OCEANOGRAPHY: GENERAL 4203 Analytical modeling and laboratory experiments 4207 Arctic and Antarctic oceanography (9310, 9315) 4211 Benthic boundary layers 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513) 4217 Coastal processes 4219 Continental shelf and slope processes (3002) 4220 Coral reef systems (4916) 4223 Descriptive and regional oceanography 4227 Diurnal, seasonal, and annual cycles (0438) 4231 Equatorial oceanography 4235 Estuarine processes (0442) 4239 Limnology (0458, 1845, 4942) 4243 Marginal and semi-enclosed seas 4247 Marine meteorology 4251 Marine pollution (0345, 0478) 4255 Numerical modeling (0545, 0560, 1952) 4259 Ocean acoustics 4260 Ocean data assimilation and reanalysis (3225) 4262 Ocean observing systems 4263 Ocean predictability and prediction (3238, 4315) 4264 Ocean optics (0649) 4271 Physical and chemical properties of seawater 4273 Physical and biogeochemical interactions 4275 Remote sensing and electromagnetic processes (0689, 2487, 3285, 4455, 6934) 4277 Time series experiments (1872, 1988, 3270, 4475) 4279 Upwelling and convergences (4964) 4283 Water masses 4294 Instruments and techniques 4299 General or miscellaneous 4500 OCEANOGRAPHY: PHYSICAL 4504 Air/sea interactions (0312, 3339) 4506 Capillary waves 4508 Coriolis effects 4512 Currents 4513 Decadal ocean variability (1616, 1635, 3305, 4215) 4515 Deep recirculations 4516 Eastern boundary currents 4520 Eddies and mesoscale processes 4522 ENSO (4922) 4524 Fine structure and microstructure 4528 Fronts and jets 4532 General circulation (1218, 1222) 4534 Hydrodynamic modeling 4536 Hydrography and tracers 4540 Ice mechanics and air/sea/ice exchange processes (0700, 0750, 0752, 0754) 4544 Internal and inertial waves 4546 Nearshore processes 4548 Ocean fog 4550 Ocean influence of Earth rotation (1223) 4553 Overflows 4554 Planetary waves 4556 Sea level: variations and mean (1222, 1225, 1641) 4558 Sediment transport (1862) 4560 Surface waves and tides (1222) 4562 Topographic/bathymetric interactions 4564 Tsunamis and storm surges (4302, 4304) 4568 Turbulence, diffusion, and mixing processes (4490) 4572 Upper ocean and mixed layer processes 4576 Western boundary currents 4594 Instruments and techniques 4599 General or miscellaneous 4800 OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL (0460) 4801 Aerosols (0305, 4906) 4803 Analytical chemistry 4802 Anoxic environments (0404, 1803, 4834, 4902) 4804 Benthic processes, benthos (0408) 4805 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4912) 4806 Carbon cycling (0428) 4807 Chemical speciation and complexation 4808 Chemical tracers 4811 Chemosynthesis 4809 Colloids 4813 Ecological prediction 4815 Ecosystems, structure, dynamics, and modeling (0439) 4817 Food webs, structure, and dynamics (0491) 4820 Gases 4825 Geochemistry 4830 Higher trophic levels 4832 Hydrothermal systems (0450, 1034, 3017, 3616, 8135, 8424) 4834 Hypoxic environments (0404, 4802) 4835 Marine inorganic chemistry (1050) 4840 Microbiology and microbial ecology (0465) 4843 Natural products chemistry 4845 Nutrients and nutrient cycling (0470, 1050) 4850 Marine organic chemistry (0470, 1050) 4851 Oxidation/reduction reactions (0471) 4852 Photochemistry 4853 Photosynthesis 4854 Physical chemistry 4855 Phytoplankton 4858 Population dynamics and ecology 4860 Radioactivity and radioisotopes 4863 Sedimentation (1861) 4866 Sorptive scavenging 4870 Stable isotopes (0454, 1041) 4872 Symbiosis 4875 Trace elements (0489) 4890 Zooplankton 4894 Instruments, sensors, and techniques 4899 General or miscellaneous 4900 PALEOCEANOGRAPHY (0473, 3344) 4901 Abrupt/rapid climate change (1605) 4902 Anthropogenic effects (1803, 4802) 4904 Atmospheric transport and circulation 4906 Aerosols (0305, 4801) 4908 Albedo 4910 Astronomical forcing 4912 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4805) 4914 Continental climate records 4916 Corals (4220) 4918 Cosmogenic isotopes (1150) 4920 Dendrochronology 4922 El Nino (4522) 4924 Geochemical tracers 4926 Glacial 4928 Global climate models (1626, 3337) 4930 Greenhouse gases 4932 Ice cores (0724) 4934 Insolation forcing 4936 Interglacial 4938 Interhemispheric phasing 4940 Isotopic stage 4942 Limnology (0458, 1845, 4239) 4944 Micropaleontology (0459, 3030) 4946 Milankovitch theory 4948 Paleocene/Eocene thermal maximum 4950 Paleoecology 4952 Palynology 4954 Sea surface temperature 4958 Speleothems 4960 Stadial 4962 Thermohaline 4964 Upwelling (4279) 4994 Instruments and techniques 4999 General or miscellaneous 5100 PHYSICAL PROPERTIES OF ROCKS 5102 Acoustic properties 5104 Fracture and flow 5109 Magnetic and electrical properties (0925) 5112 Microstructure 5114 Permeability and porosity 5120 Plasticity, diffusion, and creep 5134 Thermal properties 5139 Transport properties 5144 Wave attenuation 5194 Instruments and techniques 5199 General or miscellaneous 5200 PLANETARY SCIENCES: ASTROBIOLOGY 5205 Formation of stars and planets 5210 Planetary atmospheres, clouds, and hazes (0343) 5215 Origin of life 5220 Hydrothermal systems and weathering on other planets 5225 Early environment of Earth 5400 PLANETARY SCIENCES: SOLID SURFACE PLANETS 5405 Atmospheres (0343, 1060) 5408 Aurorae and airglow 5410 Composition (1060, 3672) 5415 Erosion and weathering 5416 Glaciation 5417 Gravitational fields (1221) 5418 Heat flow 5419 Hydrology and fluvial processes 5422 Ices 5420 Impact phenomena, cratering (6022, 8136) 5421 Interactions with particles and fields 5430 Interiors (8147) 5435 Ionospheres (2459) 5440 Magnetic fields and magnetism 5443 Magnetospheres (2756) 5445 Meteorology (3346) 5450 Orbital and rotational dynamics (1221) 5455 Origin and evolution 5460 Physical properties of materials 5462 Polar regions 5464 Remote sensing 5465 Rings and dust 5470 Surface materials and properties 5475 Tectonics (8149) 5480 Volcanism (6063, 8148, 8450) 5494 Instruments and techniques 5499 General or miscellaneous 5700 PLANETARY SCIENCES: FLUID PLANETS 5704 Atmospheres (0343, 1060) 5706 Aurorae 5709 Composition (1060) 5714 Gravitational fields (1221) 5719 Interactions with particles and fields 5724 Interiors (8147) 5729 Ionospheres (2459) 5734 Magnetic fields and magnetism 5737 Magnetospheres (2756) 5739 Meteorology (3346) 5744 Orbital and rotational dynamics (1221) 5749 Origin and evolution 5754 Polar regions 5759 Rings and dust 5770 Tidal forces 5780 Tori and exospheres 5794 Instruments and techniques 5799 General or miscellaneous 6000 PLANETARY SCIENCES: COMETS AND SMALL BODIES 6005 Atmospheres (1060) 6009 Aurorae, airglow, and X-ray emission 6008 Composition (1060) 6015 Dust 6017 Erosion and weathering 6019 Gravitational fields (1221) 6020 Ices 6022 Impact phenomena (5420, 8136) 6025 Interactions with solar wind plasma and fields 6023 Comets: dust tails and trails (6210) 6024 Interiors (8147) 6026 Ionospheres (2459) 6030 Magnetic fields and magnetism 6033 Magnetospheres (2756) 6035 Orbital and rotational dynamics 6040 Origin and evolution 6045 Physics and chemistry of materials 6050 Plasma and MHD instabilities (2149, 2752, 7836) 6055 Surfaces 6060 Radiation and chemistry 6063 Volcanism (5480, 8450) 6094 Instruments and techniques 6099 General or miscellaneous 6200 PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS 6205 Asteroids (4308) 6206 Asteroids: satellites 6207 Comparative planetology 6210 Comets (4308, 6023) 6211 Centaurs 6213 Dust 6218 Jovian satellites 6219 Io 6221 Europa 6222 Ganymede 6223 Callisto 6220 Jupiter 6224 Kuiper belt objects 6225 Mars 6230 Martian satellites 6235 Mercury 6240 Meteorites and tektites (1028, 3662) 6245 Meteors 6250 Moon (1221) 6255 Neptune 6260 Neptunian satellites 6261 Triton 6265 Planetary rings 6270 Pluto and satellites 6275 Saturn 6280 Saturnian satellites 6281 Titan 6282 Enceladus 6285 Trans-Neptunian objects 6290 Uranian satellites 6293 Uranus 6295 Venus 6296 Extra-solar planets 6297 Instruments and techniques 6299 General or miscellaneous 6300 POLICY SCIENCES (4338, 7964) 6304 Benefit-cost analysis (4333) 6309 Decision making under uncertainty (1918, 4324, 4339) 6314 Demand estimation 6319 Institutions 6324 Legislation and regulations (6615) 6329 Project evaluation 6334 Regional planning (1880, 4343) 6339 System design 6344 System operation and management (4342) 6349 General or miscellaneous 6600 PUBLIC ISSUES 6610 Funding 6615 Legislation and regulations (6324) 6620 Science policy (0485, 4338) 6630 Workforce 6699 General or miscellaneous 6900 RADIO SCIENCE 6914 Electromagnetic noise and interference 6924 Interferometry (1207, 1209, 1242) 6929 Ionospheric physics (1240, 2400) 6934 Ionospheric propagation (0689, 2487, 3285, 4275, 4455) 6939 Magnetospheric physics (2700) 6944 Nonlinear phenomena (4400, 7839) 6949 Radar astronomy 6952 Radar atmospheric physics (1220) 6954 Radio astronomy 6959 Radio oceanography (1222) 6964 Radio wave propagation 6969 Remote sensing 6974 Signal processing (0674) 6979 Space and satellite communication 6982 Tomography and imaging (7270, 8180) 6984 Waves in plasma (7867) 6994 Instruments and techniques (1241) 6999 General or miscellaneous 7200 SEISMOLOGY 7203 Body waves 7205 Continental crust (1219) 7207 Core (1212, 1213, 8124) 7208 Mantle (1212, 1213, 8124) 7209 Earthquake dynamics (1242) 7212 Earthquake ground motions and engineering seismology (4302) 7215 Earthquake source observations (1240) 7218 Lithosphere (1236) 7219 Seismic monitoring and test-ban treaty verification 7220 Oceanic crust 7221 Paleoseismology (8036) 7223 Earthquake interaction, forecasting, and prediction (1217, 1242, 4315) 7230 Seismicity and tectonics (1207, 1217, 1240, 1242) 7240 Subduction zones (1207, 1219, 1240) 7245 Mid-ocean ridges 7250 Transform faults 7255 Surface waves and free oscillations 7260 Theory 7270 Tomography (6982, 8180) 7280 Volcano seismology (4302, 8419) 7290 Computational seismology 7294 Seismic instruments and networks (0935, 3025) 7299 General or miscellaneous 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY 7504 Celestial mechanics 7507 Chromosphere 7509 Corona 7511 Coronal holes 7513 Coronal mass ejections (2101) 7514 Energetic particles (2114) 7519 Flares 7522 Helioseismology 7524 Magnetic fields 7526 Magnetic reconnection (2723, 7835) 7529 Photosphere 7531 Prominence eruptions 7534 Radio emissions 7536 Solar activity cycle (2162) 7537 Solar and stellar variability (1650) 7538 Solar irradiance 7539 Stellar astronomy 7544 Stellar interiors and dynamo theory 7546 Transition region 7549 Ultraviolet emissions 7554 X-rays, gamma rays, and neutrinos 7594 Instruments and techniques 7599 General or miscellaneous 7800 SPACE PLASMA PHYSICS 7803 Active perturbation experiments 7805 Chaos (4420) 7807 Charged particle motion and acceleration 7811 Discontinuities (2109) 7815 Electrostatic structures 7823 Ionization processes (2423) 7827 Kinetic and MHD theory 7829 Kinetic waves and instabilities 7831 Laboratory studies and experimental techniques 7835 Magnetic reconnection (2723, 7526) 7833 Mathematical and numerical techniques (0500, 3200) 7836 MHD waves and instabilities (2149, 2752, 6050) 7837 Neutral particles (2151) 7839 Nonlinear phenomena (4400, 6944) 7844 Parametric processes 7845 Particle acceleration 7846 Plasma energization 7849 Plasma interactions with dust and aerosols (2461) 7847 Radiation processes 7851 Shock waves (4455) 7852 Solitons and solitary waves (4455) 7853 Spacecraft/atmosphere interactions 7855 Spacecraft sheaths, wakes, charging 7857 Stochastic phenomena (3235, 3265, 4475) 7859 Transport processes 7863 Turbulence (4490) 7867 Wave/particle interactions (2483, 6984) 7868 Wave/wave interactions 7894 Instruments and techniques 7899 General or miscellaneous 7900 SPACE WEATHER (4305) 7904 Geomagnetically induced currents 7914 Engineering for hazard mitigation (4339) 7924 Forecasting (1922, 2722, 4315) 7934 Impacts on technological systems 7938 Impacts on humans (4323) 7944 Ionospheric effects on radio waves 7949 Ionospheric storms (2441) 7954 Magnetic storms (2788) 7959 Models 7964 Policy (2722, 6300) 7969 Satellite drag (1241) 7974 Solar effects 7984 Space radiation environment 7999 General or miscellaneous 8000 STRUCTURAL GEOLOGY 8002 Continental neotectonics (8107) 8003 Diapir and diapirism 8004 Dynamics and mechanics of faulting (8118) 8005 Folds and folding 8010 Fractures and faults 8011 Kinematics of crustal and mantle deformation 8012 High strain deformation zones 8015 Local crustal structure 8020 Mechanics, theory, and modeling 8021 Melanges 8025 Mesoscopic fabrics 8030 Microstructures 8031 Rheology: crust and lithosphere (8159) 8032 Rheology: general (8160) 8033 Rheology: mantle (8162) 8034 Rheology and friction of fault zones (8163) 8035 Pluton emplacement 8036 Paleoseismology (7221) 8038 Regional crustal structure 8040 Remote sensing 8045 Role of fluids 8094 Instruments and techniques 8099 General or miscellaneous 8100 TECTONOPHYSICS 8102 Continental contractional orogenic belts and inversion tectonics 8103 Continental cratons 8104 Continental margins: convergent 8105 Continental margins: divergent (1212, 8124) 8106 Continental margins: transform 8107 Continental neotectonics (8002) 8108 Continental tectonics: compressional 8109 Continental tectonics: extensional (0905) 8110 Continental tectonics: general (0905) 8111 Continental tectonics: strike-slip and transform 8115 Core processes (1213, 1507) 8118 Dynamics and mechanics of faulting (8004) 8120 Dynamics of lithosphere and mantle: general (1213) 8121 Dynamics: convection currents, and mantle plumes 8122 Dynamics: gravity and tectonics 8123 Dynamics: seismotectonics 8124 Earth's interior: composition and state (1212, 7207, 7208, 8105) 8125 Evolution of the Earth (0325) 8130 Heat generation and transport 8135 Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8424) 8136 Impact phenomena (5420, 6022) 8137 Hotspots, large igneous provinces, and flood basalt volcanism 8138 Lithospheric flexure 8139 Obduction tectonics 8140 Ophiolites (3042) 8145 Physics of magma and magma bodies 8147 Planetary interiors (5430, 5724, 6024) 8148 Planetary volcanism (5480, 8450) 8149 Planetary tectonics (5475) 8150 Plate boundary: general (3040) 8155 Plate motions: general (3040) 8157 Plate motions: past (3040) 8158 Plate motions: present and recent (3040) 8159 Rheology: crust and lithosphere (8031) 8160 Rheology: general (1236, 8032) 8162 Rheology: mantle (8033) 8163 Rheology and friction of fault zones (8034) 8164 Stresses: crust and lithosphere 8166 Stresses: deep-seated 8168 Stresses: general 8169 Sedimentary basin processes 8170 Subduction zone processes (1031, 3060, 3613, 8413) 8175 Tectonics and landscape evolution 8177 Tectonics and climatic interactions 8178 Tectonics and magmatism 8180 Tomography (6982, 7270) 8185 Volcanic arcs 8194 Instruments and techniques 8199 General or miscellaneous 8400 VOLCANOLOGY 8410 Geochemical modeling (1009, 3610) 8411 Thermodynamics (0766, 1011, 3611) 8412 Reactions and phase equilibria (1012, 3612) 8413 Subduction zone processes (1031, 3060, 3613, 8170) 8416 Mid-oceanic ridge processes (1032, 3614) 8415 Intra-plate processes (1033, 3615) 8424 Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8135) 8425 Effusive volcanism (4302) 8426 Mud volcanism (4302) 8427 Subaqueous volcanism 8428 Explosive volcanism (4302) 8450 Planetary volcanism (5480, 6063, 8148) 8404 Volcanoclastic deposits 8408 Volcano/climate interactions (1605, 3309, 4321) 8409 Atmospheric effects (0370) 8430 Volcanic gases 8429 Lava rheology and morphology 8434 Magma migration and fragmentation 8414 Eruption mechanisms and flow emplacement 8439 Physics and chemistry of magma bodies 8440 Calderas 8445 Experimental volcanism 8455 Tephrochronology (1145) 8485 Remote sensing of volcanoes (4337) 8486 Field relationships (1090, 3690) 8419 Volcano monitoring (4302, 7280) 8488 Volcanic hazards and risks (4302, 4328, 4333) 8494 Instruments and techniques 8499 General or miscellaneous 9300 GEOGRAPHIC LOCATION 9305 Africa 9310 Antarctica (4207) 9315 Arctic region (0718, 4207) 9320 Asia 9325 Atlantic Ocean 9330 Australia 9335 Europe 9340 Indian Ocean 9345 Large bodies of water (e.g., lakes and inland seas) (0746) 9350 North America 9355 Pacific Ocean 9360 South America 9399 General or miscellaneous 9600 INFORMATION RELATED TO GEOLOGIC TIME 9604 Cenozoic 9605 Neogene 9606 Paleogene 9609 Mesozoic 9610 Cretaceous 9611 Jurassic 9612 Triassic 9614 Paleozoic 9615 Permian 9616 Carboniferous 9617 Devonian 9618 Silurian 9620 Ordovician 9621 Cambrian 9619 Precambrian 9622 Proterozoic 9623 Archean 9699 General or miscellaneous 9800 GENERAL OR MISCELLANEOUS 9805 Instruments useful in three or more fields 9810 New fields (not classifiable under other headings) 9815 Notices and announcements 9820 Techniques applicable in three or more fields 9900 CORRECTIONS