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01 agosto, 2016

Antenas de celular medem chuva com precisão


Sensor de chuva

Uma das maiores dificuldades que os meteorologistas encontram para fazer melhores previsões é a falta de sensores que lhes deem dados estatísticos suficientes para uma amostragem significativa e com alta resolução espacial.
Hoje, eles dependem de pluviômetros, geralmente instalados em estações muito espaçadas, ou de radares, muito caros e dificilmente disponíveis para todas as áreas.
A boa notícia é que a rede de telefonia celular - mais especificamente, as ondas que trafegam entre as antenas e entre as antenas e os celulares - pode se transformar em um gigantesco sensor capaz de monitorar a chuva em grandes áreas e com alta resolução.


 A qualidade dos dados de precipitação obtidos pelo programa é a mesma dos pluviômetros, mas com a grande vantagem da maior resolução espacial e da disponibilização dos dados em tempo real. [Imagem: Christian Chwala]


A descoberta de que as gotas de chuva atenuam a propagação das ondas eletromagnéticas de uma forma mensurável foi feita por Christian Chwala e seus colegas do Instituto de Tecnologia Karlsruhe, na Alemanha.
Chwal desenvolveu um programa de computador que consegue derivar a informação sobre as precipitações atmosféricas a partir de flutuações nos sinais recebidos pelas antenas das estações de telefonia celular. Segundo ele, a técnica poderá ser a solução para áreas com pequena cobertura de sensores, como os países mais pobres.

Pluviômetro eletromagnético

"Os pingos de chuva são quase tão grandes quanto o comprimento de onda da radiação de micro-ondas dos links de rádio operando em frequências de 15 a 40 gigahertz. Por esta razão, eles atenuam fortemente a radiação nesta faixa de frequência," explica o professor Harald Kunstmann, coordenador do trabalho.
Quanto mais forte for a chuva, maior é a diminuição da potência do sinal entre duas antenas. Os usuários de celulares dificilmente notam o efeito, a não ser em casos de tempestades, quando então o sinal é interrompido e a ligação cai.
A qualidade dos dados de precipitação obtidos pelo programa é a mesma dos pluviômetros, mas com a grande vantagem da maior resolução espacial e da disponibilização dos dados em tempo real. "O limite de detecção é uma chuva de um milímetro por hora, e os dados ficam disponíveis com um retardo de apenas um minuto," disse Chwala.

Bibliografia:

Real-time data acquisition of commercial microwave link networks for hydrometeorological applications
Christian Chwala, Felix Keis, Harald Kunstmann
Atmospheric Measurement Techniques
Vol.: 9, Issue 3, 991-999
DOI: 10.5194/amt-9-991-2016

Onde caem mais raios na Terra?


Censo de raios
Embora seja um questionamento comum aos estatísticos, as probabilidades de uma pessoa ser atingida por um raio são quase sempre retratadas como muito remotas. No entanto, no mês de maio, incidentes envolvendo raios bateram recordes ao atingirem dezenas de pessoas ao redor do mundo.
Em Bangladesh, durante violentas tempestades tropicais, foram 65 vítimas fatais em apenas quatro dias. Na França e na Alemanha, dezenas de pessoas ficaram feridas durante fortes chuvas, incluindo um grupo de crianças de 9 a 11 anos, atingidas por um raio durante uma partida de futebol. No Brasil houve ao menos uma vítima fatal no período.
Mas onde caem mais raios no planeta Terra? E por que caem tantos em alguns lugares?



Sensor de raios

Liderados pela professora Rachel Albrecht, do Instituto de Astronomia, Geofísica e Ciências Atmosféricas da USP, pesquisadores da NASA e de diversas universidades se reuniram para tentar responder a essas perguntas.
Usando um sensor de raios chamado LIS (Lightning Imaging Sensor), a bordo do satélite de observações TRMM (Tropical Rainfall Measuring Mission) da Nasa, a equipe compôs um mapa que mostra as principais zonas de incidência de raios ao redor do planeta.
"O sensor foi lançado no final de 1997 e descomissionado em 2015," conta Rachel. "Desde 2009, monitoramos os máximos de raios, fazendo a climatologia, e agora, como o satélite não está mais operando, encerramos com 16 anos de dados, incluindo de 1998 até 2013."

Video Raios Maracibo

Raios na região do Lago Maracaibo, na Venezuela, o local onde caem mais raios no mundo.
Onde caem mais raios na Terra?

Os dados permitiram compor um ranking que lista os 500 locais com maior incidência de raios no mundo.
Individualmente, o Lago Maracaibo, na Venezuela, é a capital mundial dos raios. Até então, a maior densidade de raios tinha sido encontrada no Congo, na África.
De fato, 283 locais apontados no mapa estão na África, uma região que, de acordo com Rachel, tem desenvolvimento de sistemas convectivos de mesoescala durante o ano inteiro e numa área grande.
O Brasil começa a aparecer na posição 191, e o local com mais raios fica localizado ao noroeste de Manaus, próximo do Rio Negro. Contudo, quando se somam todos os raios sobre o território nacional, o Brasil é o país com mais raios no mundo, devido a sua dimensão continental e por estar nos trópicos. "Só no Brasil temos, em média, aproximadamente 110 milhões de raios totais por ano", disse Rachel.

[..."Hoje temos cerca de 120 mortes por ano e 500 pessoas feridas, ou seja, 620 pessoas são atingidas por ano no Brasil. 
O Brasil é o país com maior incidência de raios no mundo.
"São entre 50 e 60 milhões de descargas por ano, com maior volume no verão", todas as regiões do país têm áreas com alta incidência de raios, como a parte oeste dos estados da Região Sul e a área da Grande São Paulo, no Sudeste, e o estado do Piauí, no Nordeste....]


Indicativos de mudanças climáticas

Uma das principais conclusões do estudo é que a incidência de raios está relacionada com as características dos respectivos locais, como a topografia ou vegetação.
Para o futuro, os pesquisadores pretendem analisar se, nesses 16 anos, houve um aumento ou uma diminuição na intensidade das tempestades, não apenas no número de raios, mas se estão mais intensas ou não. A ideia é "ter um indício do que está ocorrendo em termos de mudanças climáticas nessa última década e meia", finaliza Rachel.


Referência:

Where are the lightning hotspots on Earth?
Rachel I. Albrecht, Steven J. Goodman, Dennis E. Buechler, Richard J. Blakeslee, Hugh J. Christian
Bulletin of the American Meteorological Society
DOI: 10.1175/BAMS-D-14-00193.1

Sons da Aurora Boreal


Em 2012, um grupo liderado pelo professor Unto Laine, da Universidade Aalto, na Finlândia, demonstrou que um daqueles "mitos históricos" - os relatos de que a aurora boreal emitia sons - era um fato.
E, mais do que isso, a equipe demonstrou que, embora as Luzes do Norte ocorram a altitudes entre 80 e 150 km, a fonte dos sons associados a elas parecia estar localizada bem perto do chão, a uma altitude de aproximadamente 70 metros.
Agora a equipe encontrou uma explicação para o mecanismo que cria o som e confirmou sua origem de baixa altitude. Para isso, eles combinaram medições acústicas locais com os perfis de temperatura atmosférica medidos pelo Instituto Meteorológico da Finlândia.



Camada de inversão

Em um fenômeno que a equipe chamou de "hipótese da camada de inversão", os estalidos e crepitares associados com a Aurora Boreal surgem quando a tempestade geomagnética que produz as luzes na alta atmosfera ativa as cargas elétricas que se acumularam na camada de inversão da atmosfera, fazendo-as descarregar como se fossem minúsculos raios.
"As temperaturas geralmente caem quanto maior a altitude. No entanto, quando as temperaturas estão bem abaixo de zero e, em geral em condições climáticas claras e calmas durante a tarde e a noite, o frio fica perto da superfície e o ar mais quente fica em cima.
"Esse ar quente não se mistura, ele sobe em direção a uma camada mais fria levando cargas negativas do solo. A camada de inversão forma uma espécie de tampa, dificultando os movimentos verticais das cargas. O ar mais frio acima dela é positivamente carregado.
"Finalmente, uma tempestade geomagnética faz com que as cargas acumuladas descarreguem na forma de faíscas que criam pulsos magnéticos e sonoros mensuráveis," explica o professor Laine.

Mistérios das auroras boreais

De acordo com o pesquisador, a hipótese da camada de inversão também dá uma explicação crível de por quê os sons das auroras boreais só são ouvidos em condições meteorológicas calmas.
Ele enfatiza que a hipótese não exclui outros mecanismos, mas esta é a primeira explicação para todos os três mistérios relacionados aos sons das auroras polares.
"Além do mecanismo que gera o som, isso nos ajuda a entender como podemos ouvir o som quando a fonte de luz da aurora está a uma distância de 80 a 100 km. A hipótese da camada de inversão também oferece respostas para como é possível que os eventos sonoros ocorram quase simultaneamente com as observações visuais: partindo de uma altitude de 75 metros, o som atinge o ouvido humano em apenas 0,2 segundo," conclui ele.


Bibliografia:

Auroral Acoustics project - a progress report with a new hypothesis
Unto Kalervo Laine
Vol.: To be published
 
Fonte: http://www.inovacaotecnologica.com.br/noticias/noticia.php?artigo=sons-da-aurora-boreal&id=010125160627

09 dezembro, 2015

Blitzdienst: Die Zähler des Zeus

Wo immer Zeus in Europa seinen Blitz schleudert, Stephan Thern registriert es. Sein Blitzdienst meldet nur Sekunden später, wo es eingeschlagen hat. 

 

Stephan Thern vom Siemens Blitz-Informationsdienst (BLIDS) in Karlsruhe (Baden-Württemberg) stehtvor einer Bildmontage des Karlsruher Schlosses. Foto: dpa

Karlsruhe.Wenn sich am Himmel Gewitterwolken zusammenballen, kann Stephan Thern gar nicht anders, als seinen Computer anzuwerfen. „Ich will dann natürlich wissen, ob wir das Unwetter auf dem Schirm haben“, erzählt der Elektrotechniker und ein kleines Lächeln umspielt seinen Mund. Bislang hat ihn die Technik nie enttäuscht.

150 Stationen in Europa

Der von Thern geführte Blitzdienst von Siemens in Karlsruhe registriert im Schnitt rund eine Million Entladungen im Jahr über Deutschland. Für die Aufzeichnung reichen 16 Messpunkte in Deutschland aus sowie weitere rund 150 Stationen, die Siemens gemeinsam mit Partnern in Europa betreibt. Für die Informationen interessieren sich vor allem Energieversorger und Flughäfen, Versicherungen und Organisatoren von Großveranstaltungen.

Die Blitze lassen sich leicht messen. Bei ihrer Entladung setzen sie eine elektromagnetische Welle frei, die sich mit hoher Geschwindigkeit in alle Richtungen ausbreitet. Die Messstationen in einer Entfernung von bis zu 600 Kilometern können dieses Feld garantiert aufzeichnen. „Die Reichweite ist aber weit größer“, erklärt Thern. „Wir haben mit unserer Karlsruher Station schon Blitze über Portugal gemessen.“
Wird ein Blitz von mindestens zwei Stationen aufgezeichnet, kann anhand des Abgleichs von Zeit und Entfernung der Punkt der Entladung errechnet werden. Je mehr Stationen Daten liefern, desto exakter kann der Blitzdienst den Ort eingrenzen. „Im Moment liegen wir bei einer Genauigkeit von 200 bis 700 Metern.“
Wo Blitze eingeschlagen haben, interessiert in erster Linie die Betreiber von Freileitungen. „Wenn bei ihnen eine Leitung ausfällt, wollen sie wissen, ob ein Blitz dafür verantwortlich ist oder doch ein umgefallener Baum“, erklärt Thern. „Falls wir den Blitz bestätigen, kann die Leitung schnell wieder ans Netz genommen werden, bei einem Baum dauern die Aufräumarbeiten etwas länger.“

Versicherungen greifen auf Daten zurück

Versicherungen benötigen die Daten, um zu prüfen, ob sie Schadenersatz leisten müssen. „Die meisten Schäden entstehen ja nicht durch den Blitzschlag selbst, sondern durch die Überspannung. Das kann zu Kurzschlüssen in Geräten führen, die in einem Radius von 2,5 Kilometern vom Blitzschlag entfernt stehen“, erläutert Thern.
Nach Angaben des Gesamtverbandes der Deutschen Versicherungswirtschaft werden pro Jahr zwischen 300 000 und 550 000 durch Blitz verursachte Schadensfälle gemeldet. Die Gesamtschadenssumme liegt bei rund 300 Millionen Euro. Mit Hilfe des Blitzdienstes können die Versicherungen schnell sehen, ob die Angaben ihrer Kunden stimmig sind oder nicht.
Doch das Blitz-Team belässt es nicht bei der bloßen Zählung. Seine Daten dienen auch der Warnung. „Wir haben sogar einige Kunden, für die wir sensible Anlagen abschalten können, wenn sich ein Gewitter nähert.“ Darunter fallen Rechenzentren und Windräder älterer Bauart, deren Rotorblätter sich bei Blitzeinschlägen lösen können.
Seit einigen Jahren arbeitet der Dienst auch an einer Kombination der Blitzeinschläge mit anderen Wetterdaten, um Gewitterverläufe besser vorhersagen zu können. „Das ist dann vor allem für Großveranstaltungen interessant, die wissen wollen, was da auf sie zukommt – ob sie evakuieren müssen oder nicht.“ Erste Interessenten gebe es bereits.
Hinweise auf den Klimawandel, bei dem heftigere Stürme vorausgesagt werden, kann Thern in seinen Daten nicht finden. „Dafür sind die Schwankungen zwischen den einzelnen Jahren zu hoch.“ Im Schnitt wird eine deutsche Region an 16 bis 36 Tagen im Jahr von Gewittern heimgesucht, 95 Prozent aller Blitze schlagen zwischen Mai und September zu.


Die Höhenlagen im Süden sind dabei stärker betroffen als die flachen Lagen im Norden. Dort ziehen allerdings Windräder Blitze magisch an. „Das sind die reinsten Blitzfänger“, sagt Thern und zeigt auf die Auswertung von 30 Einschlägen in Norddeutschland an einem Tag im Mai. In fast allen Fällen stand eine Windkraftanlage im Mittelpunkt.
In den vergangenen Wochen wurde Thern nur selten von Gewitterwolken an seinen Computer gelockt. „Bislang hatten wir ein sehr ruhiges Jahr“, sagt er, obwohl es in einigen Regionen heftige Pfingstunwetter gab. Aber der richtige Sommer kommt ja vielleicht noch, und dann gibt es wieder Feuerwerk auf den Rechnern: wenn mit einer Gewitterfront bis zu 200 000 Blitze über Deutschland niedergehen. (dpa)

Font: http://www.mittelbayerische.de/panorama-nachrichten/blitzdienst-die-zaehler-des-zeus-21934-art1088623.html

Laser é capaz de guiar os Raios


Raios podem ser guiados com laser
O laser faz com que a descarga elétrica execute caminhos complexos e desvie de obstáculos. [Imagem: Matteo Clerici - 10.1126/sciadv.1400111]


Raios guiados por laser

Pára-raios são bons, mas muito longe do ideal, sobretudo porque eles não estabelecem o caminho do raio, que geralmente espalha-se pelas cercanias.
A ideia de Matteo Clerici, do Instituto Nacional de Pesquisas Científicas do Canadá, é usar raios laser para guiar cuidadosamente o raio, até o seu destino final no solo.
O conceito funcionou bem, ao menos em pequena escala, em raios criados em laboratório, simulados por descargas elétricas entre dois eletrodos.
Clerici conseguiu dirigir com precisão os raios simulados, fazendo-os não apenas cair no lugar certo, mas até mesmo desviar-se de obstáculos no meio do caminho.
As descargas elétricas também foram dirigidas para seguir linhas retas ou trajetórias parabólicas entre a origem e o destino.

Raio desvia de obstáculo

Os experimentos mostraram que o trajeto do raio pode ser controlado ajustando o "formato" dos feixes de laser. Combinando diversos feixes, foi possível até mesmo fazer o raio atingir o receptor seguindo uma trajetória em "S".
Quando controlada para desviar de obstáculos, a descarga mudou o trajeto com precisão, passando sem danificar o objeto que servia de obstáculo.

Raios podem ser guiados com laser
É o formato do feixe de laser que estabelece a trajetória do raio. [Imagem: Matteo Clerici - 10.1126/sciadv.1400111]


O experimento é mais simples e possibilita um controle muito maior do que experimento similar realizado em 2012 por pesquisadores franceses, que fizeram os raios seguirem a trajetória retilínea de um laser pulsado.
As aplicações práticas, porém, ao menos em raios de verdade, deverão demorar, uma vez que também estes novos experimentos exigiram lasers de alta potência e manipularam descargas de poucos centímetros.
Mas descargas elétricas não acontecem apenas durante tempestades, sendo usadas diariamente em todos os motores a combustão e em equipamentos de solda, por exemplo, o que pode indicar aplicações promissoras em outras áreas.

Bibliografia:

Laser-assisted guiding of electric discharges around objects
Matteo Clerici, Yi Hu, Philippe Lassonde, Carles Milián, Arnaud Couairon, Demetrios N. Chrisodoulides, Zhigang Chen, Luca Razzari, François Vidal, François Légaré, Daniele Faccio, Roberto Morandotti
Science Advances
Vol.: 1, No. 5
DOI: 10.1126/sciadv.1400111

 




















14 maio, 2015

O mapa de um trovão



Pela primeira vez os cientistas conseguiram capturar um mapa da explosão de radiação a partir de um relâmpago. O Héliofísico Maher Dayeh conseguiu registrar um mapa sonoro do trovão.
 
Uma corrente elétrica rapidamente flui do centro de cargas negativo da nuvem e segue para o solo, o relâmpago rapidamente aquece e expande o ar a sua volta, gerando ondas de choque.
Fonte: https://www.sciencenews.org/article/scientists-take-first-picture-thunder

15 agosto, 2014

Qual área de pesquisa seguir?

Esta é uma lista de algumas áreas de pesquisa. Foi retirada das opções de área do Journal of Geophysical Research Atmospheres, a serem escolhidas no momento de submissão de "qualquer" artigo, para aquele Journal.


ATMOSPHERIC COMPOSITION AND STRUCTURE
Aerosols and particles (0345, 4801, 4906)
Airglow and aurora
Air/sea constituent fluxes (3339, 4504)
Biosphere/atmosphere interactions (0426, 1610)
Chemical kinetic and photochemical properties
Cloud optics
Cloud physics and chemistry
Cloud/radiation interaction
Constituent sources and sinks
Evolution of the atmosphere (1610, 8125)
Exosphere
Geochemical cycles (1030)
Ion chemistry of the atmosphere (2419, 2427)
Middle atmosphere: composition and chemistry
Middle atmosphere: constituent transport and chemistry (3334)
Middle atmosphere: energy deposition (3334)
Planetary atmospheres (5210, 5405, 5704)
Pollution: urban and regional (0305, 0478, 4251, 4325)
Pressure, density, and temperature
Thermosphere: composition and chemistry
Thermosphere: energy deposition (3369)
Radiation: transmission and scattering
Troposphere: composition and chemistry
Troposphere: constituent transport and chemistry
Volcanic effects (4301, 8409)
Instruments and techniques
General or miscellaneous
BIOGEOSCIENCES
Agricultural systems
Anoxic and hypoxic environments (4802, 4834)
Astrobiology and extraterrestrial materials
Benthic processes (4804)
Bioavailability: chemical speciation and complexation
Biodiversity
Biogeochemical kinetics and reaction modeling (0414, 0793, 1615, 4805, 4912)
Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
Biogeophysics
Bioremediation
Biomineralization
Biomolecular and chemical tracers
Bio-optics
Biosignatures and proxies
Biosphere/atmosphere interactions (0315)
Carbon cycling (4806)
Climate dynamics (1620)
Computational methods and data processing
Contaminant and organic biogeochemistry (0792)
Data sets
Diel, seasonal, and annual cycles (4227)
Ecosystems, structure and dynamics (4815)
Estuarine and nearshore processes (4235)
Evolutionary geobiology
Geomicrobiology
Hydrothermal systems (1034, 3017, 3616, 4832, 8135, 8424)
Instruments and techniques
Isotopic composition and chemistry (1041, 4870)
Life in extreme environments
Limnology (1845, 4239, 4942)
Macro- and micropaleontology (3030, 4944)
Marine systems (4800)
Metals
Microbe/mineral interactions
Microbiology: ecology, physiology and genomics (4840)
Modeling (1952, 4316)
Natural hazards (4308)
Nitrogen cycling
Nutrients and nutrient cycling (4845, 4850)
Oxidation/reduction reactions (4851)
Paleoclimatology and paleoceanography (3344, 4900)
Permafrost, cryosphere, and high-latitude processes (0702, 0716)
Plant ecology (1851)
Pollution: urban, regional and global (0345, 4251, 4325)
Remote sensing
Restoration
Riparian systems (0744, 1856)
Science policy (6620)
Soils/pedology (1865)
Sulfur cycling
Trace element cycling (4875)
Trace gases
Food webs and trophodynamics (4817)
Urban systems (4325)
Water/energy interactions (1878)
Water quality
Wetlands (1890)
General or miscellaneous
New fields (not classifiable under other headings)
COMPUTATIONAL GEOPHYSICS (1980, 3200, 3252, 4307, 4314, 7833)
Agent-based models
Cellular automata
Data analysis: algorithms and implementation
Data management
Data presentation and visualization (1994)
Hardware solutions
Image processing
Modeling (1952, 4255, 4316)
Model verification and validation
Neural networks, fuzzy logic, machine learning (1942)
Numerical solutions (4255)
Instruments and techniques
General or miscellaneous
CRYOSPHERE (4540)
Permafrost (0475, 4308)
Seasonally frozen ground
Active layer
Thermokarst
Periglacial processes
Cryosol
Clathrate
Cryobiology (0475)
Tundra (9315)
Glaciers
Rock glaciers
Ice cores (4932)
Ice sheets
Ice shelves
Ice streams
Icebergs
Icing (aufeis, naled)
Snow (1827, 1863)
Ice (1863)
Snowmelt
Avalanches (4302)
Rivers (0483, 1856)
Lakes (9345)
Ponds
Sea ice (4540)
Polynas (4540)
Leads (4540)
Remote sensing
Engineering
Mass balance (1218, 1223)
Energy balance
Thermodynamics (1011, 3611, 8411)
Thermal regime
Properties
Distribution
Dynamics
Glaciology (1621, 1827, 1863)
Weathering (1625, 1886)
Contaminants (0432)
Biogeochemistry (0412, 0414, 1615, 4805, 4912)
Instruments and techniques
Modeling (1952, 4316)
General or miscellaneous
EDUCATION
Elementary and secondary education
Post-secondary education
Informal education
Curriculum and laboratory design
Teaching methods
Teacher training
Evaluation and assessment
Instructional tools
Geoscience education research
Diversity
ELECTROMAGNETICS
Antenna arrays
Antennas
Biological effects
Electromagnetic theory
Guided waves
Inverse scattering
Measurement and standards
Nonlinear electromagnetics
Numerical methods
Optics (4264)
Plasmas
Random media and rough surfaces
Reflectors and feeds
Scattering and diffraction
Signal processing and adaptive antennas (6974)
Singularity expansion method
Transient and time domain
Wave propagation (2487, 3285, 4275, 4455, 6934)
Instruments and techniques
General or miscellaneous
EXPLORATION GEOPHYSICS
Computational methods: seismic
Computational methods: potential fields (1214)
Continental structures (8109, 8110)
Data processing
Downhole methods
Gravity methods (1219)
Magnetic and electrical methods (5109)
Oceanic structures
Radioactivity methods
Remote sensing
Seismic methods (3025, 7294)
Instruments and techniques
General or miscellaneous
GEOCHEMISTRY
Geochemical modeling (3610, 8410)
Thermodynamics (0766, 3611, 8411)
Reactions and phase equilibria (3612, 8412)
Subduction zone processes (3060, 3613, 8170, 8413)
Mid-oceanic ridge processes (3614, 8416)
Intra-plate processes (3615, 8415)
Hydrothermal systems (0450, 3017, 3616, 4832, 8135, 8424)
Alteration and weathering processes (3617)
Magma chamber processes (3618)
Magma genesis and partial melting (3619)
Mantle processes (3621)
Composition of the core
Composition of the continental crust
Composition of the oceanic crust
Composition of the hydrosphere
Composition of the biosphere
Composition of the mantle
Composition of the moon
Composition of the planets
Composition of meteorites (3662, 6240)
Composition of aerosols and dust particles
Geochemical cycles (0330)
Major and trace element geochemistry
Radiogenic isotope geochemistry
Stable isotope geochemistry (0454, 4870)
Mineral and crystal chemistry (3620)
Fluid and melt inclusion geochemistry
Marine geochemistry (4835, 4845, 4850)
Sedimentary geochemistry
Organic and biogenic geochemistry
Planetary geochemistry (5405, 5410, 5704, 5709, 6005, 6008)
Field relationships (3690, 8486)
Instruments and techniques
General or miscellaneous
GEOCHRONOLOGY
Quaternary geochronology
Sidereal geochronology
Radioisotope geochronology
Isotopic disequilibrium dating
Chemical and biological geochronology
Geomorphological geochronology
Correlative geochronology
Thermochronology
Tephrochronology (8455)
Cosmogenic-nuclide exposure dating (4918)
Extinct radionuclide geochronology
Planetary and lunar geochronology
Sedimentary geochronology
Instruments and techniques
General or miscellaneous
GEODESY AND GRAVITY
Standards and absolute measurements
Instruments and techniques
Integrations of techniques
Satellite geodesy: results (6929, 7215, 7230, 7240)
Satellite geodesy: technical issues (6994, 7969)
Space geodetic surveys(4337)
Control surveys
Seismic cycle related deformations (6924, 7209, 7223, 7230)
Transient deformation (6924, 7230, 7240)
Tectonic deformation (6924)
Non-tectonic deformation
Earth's interior: composition and state (7207, 7208, 8105, 8124)
Earth's interior: dynamics (1507, 7207, 7208, 8115, 8120)
Rheology of the lithosphere and mantle (7218, 8160)
Gravity anomalies and Earth structure (0920, 7205, 7240)
Geopotential theory and determination (0903)
Time variable gravity (7223, 7230)
Reference systems
Earth rotation variations
Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
Mass balance (0762, 1223, 1631, 1836, 1843, 3010, 3322, 4532)
Atmosphere monitoring with geodetic techniques (6952)
Ocean monitoring with geodetic techniques (1225, 1641, 3010, 4532, 4556, 4560, 6959)
Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
Lunar and planetary geodesy and gravity (5417, 5450, 5714, 5744, 6019, 6250)
General or miscellaneous (1709)
GEOMAGNETISM AND PALEOMAGNETISM
Archeomagnetism
Biogenic magnetic minerals
Core processes (1213, 8115)
Dynamo: theories and simulations
Environmental magnetism
Geomagnetic excursions
Geomagnetic induction
Magnetic anomalies: modeling and interpretation
Magnetic fabrics and anisotropy
Magnetic mineralogy and petrology
Magnetostratigraphy
Paleointensity
Paleomagnetic secular variation
Paleomagnetism applied to tectonics: regional, global
Paleomagnetism applied to geologic processes
Rapid time variations
Reference fields: regional, global
Remagnetization
Reversals: process, timescale, magnetostratigraphy
Rock and mineral magnetism
Satellite magnetics: main field, crustal field, external field
Spatial variations: all harmonics and anomalies
Spatial variations attributed to seafloor spreading (3005)
Time variations: diurnal to decadal
Time variations: secular and longer
Instruments and techniques
Planetary magnetism: all frequencies and wavelengths
General or miscellaneous
GLOBAL CHANGE
Abrupt/rapid climate change (4901, 8408)
Atmosphere (0315, 0325)
Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
Climate variability (1635, 3305, 3309, 4215, 4513)
Climate dynamics (0429, 3309)
Cryospheric change (0776)
Earth system modeling (1225, 4316)
Geomorphology and weathering (0790, 1824, 1825, 1826, 1886)
Global climate models (3337, 4928)
Coupled models of the climate system
Impacts of global change (1225, 4321)
Land/atmosphere interactions (1218, 1843, 3322)
Land cover change
Oceans (1616, 3305, 4215, 4513)
Regional climate change (4321)
Remote sensing (1855, 4337)
Sea level change (1222, 1225, 4304, 4556)
Solid Earth (1225)
Solar variability (7537)
Water cycles (1836)
Instruments and techniques
General or miscellaneous
HISTORY OF GEOPHYSICS
Atmospheric sciences
Biogeosciences
Computational geophysics
Cryosphere
Geochronology
Geodesy (1299)
Geomagnetism and paleomagnetism
Hydrology
Nonlinear geophysics
Ocean sciences
Planetology
Seismology
Solar/planetary relationships
Tectonophysics
Volcanology, geochemistry, and petrology
Instruments and techniques
General or miscellaneous
HYDROLOGY
Anthropogenic effects (4802, 4902)
Catchment
Chemistry of fresh water
Climate impacts (4321)
Computational hydrology
Dams
Debris flow and landslides (4303)
Desertification
Drought (4303)
Eco-hydrology
Energy budgets
Erosion
Estimation and forecasting (4315)
Evapotranspiration
Extreme events (4313)
Floods (4303)
Floodplain dynamics
Frozen ground
Geographic Information Systems (GIS)
Geomechanics
Geomorphology: general (1625)
Geomorphology: fluvial (1625)
Geomorphology: hillslope (1625)
Glaciology (0736, 0776, 1863)
Groundwater hydraulics
Groundwater hydrology
Groundwater quality
Groundwater/surface water interaction
Groundwater transport
Human impacts (4323)
Hydroclimatology
Hydrogeophysics
Hydrological cycles and budgets (1218, 1655)
Hydrometeorology
Hydrologic scaling
Infiltration
Irrigation
Land/atmosphere interactions (1218, 1631, 3322)
Limnology (0458, 4239, 4942)
Model calibration (3333)
Modeling (1952, 4316)
Monitoring networks
Numerical approximations and analysis (3336)
Overland flow
Plant ecology (0476)
Plant uptake
Precipitation (3354)
Precipitation-radar
Remote sensing (1640, 4337)
Reservoirs (surface)
River channels (0483, 0744)
Rocks: chemical properties
Rocks: physical properties
Streamflow
Sedimentation (4863)
Sediment transport (4558)
Snow and ice (0736, 0738, 0776, 1827)
Soils (0486)
Soil moisture
Stochastic hydrology
Surface water quality
Time series analysis (1988, 3270, 4277, 4475)
Uncertainty assessment (1990, 3275)
Ungaged basins
Vadose zone
Water budgets
Water/energy interactions (0495)
Watershed
Water management (6334)
Water supply
Weathering (0790, 1625)
Wetlands (0497)
Instruments and techniques: modeling
Instruments and techniques: monitoring
General or miscellaneous
INFORMATICS
Community modeling frameworks
Community standards
Computational models, algorithms
Cyberinfrastructure
Data assimilation, integration and fusion
Data management, preservation, rescue
Data mining
Data and information discovery
Decision analysis (4324, 6309)
Emerging informatics technologies
Forecasting (2722, 4315, 7924)
Formal logics and grammars
Geospatial
GIS science
Data and information governance
High-performance computing
International collaboration
Interoperability
Knowledge representation and knowledge bases
Machine-to-machine communication
Machine learning (0555)
Markup languages
Metadata
Metadata: Provenance
Metadata: Quality
Modeling (0466, 0545, 0798, 1847, 4255, 4316)
Natural language processing
Numerical algorithms
Ontologies
Portals and user interfaces
Query languages for science, markup languages, ontologies
Real-time and responsive information delivery (4346)
Rules and logic
Scientific reasoning/inference
Semantic web and semantic integration
Sensor web
Social networks
Software tools and services
Software re-use
Spatial analysis and representation (0500, 3252)
Standards
Statistical methods: Descriptive (4318)
Statistical methods: Inferential (4318)
Temporal analysis and representation (1872, 3270, 4277, 4475)
Uncertainty (1873, 3275)
Virtual globes
Visualization and portrayal (0530)
Web Services
Workflow
General or miscellaneous
INTERPLANETARY PHYSICS
Coronal mass ejections (4305, 7513)
Corotating streams
Cosmic rays
Discontinuities (7811)
Ejecta, driver gases, and magnetic clouds
Energetic particles (7514)
Heliopause and solar wind termination
Heliosphere/interstellar medium interactions
Interplanetary dust
Interplanetary magnetic fields
Interplanetary shocks
Interstellar gas
MHD waves and turbulence (2752, 6050, 7836)
Neutral particles (7837)
Pickup ions
Planetary bow shocks
Plasma waves and turbulence
Solar cycle variations (7536)
Solar wind plasma
Solar wind sources
Instruments and techniques
General or miscellaneous
IONOSPHERE (6929)
Active experiments
Auroral ionosphere (2704)
Current systems (2721)
Electric fields (2712)
Equatorial ionosphere
Ion chemistry and composition (0335)
Ionization processes (7823)
Ionosphere/atmosphere interactions (0335)
Ionosphere/magnetosphere interactions (2736)
Ionospheric disturbances
Ionospheric dynamics
Ionospheric irregularities
Ionospheric storms (7949)
Meteor-trail physics
Midlatitude ionosphere
Modeling and forecasting
Particle acceleration
Particle precipitation
Planetary ionospheres (5435, 5729, 6026)
Plasma interactions with dust and aerosols (7849)
Plasma convection (2760)
Plasma temperature and density
Plasma waves and instabilities (2772)
Polar cap ionosphere
Solar radiation and cosmic ray effects
Topside ionosphere
Wave/particle interactions (7867)
Wave propagation (0689, 3285, 4275, 4455, 6934)
Instruments and techniques
General or miscellaneous
MAGNETOSPHERIC PHYSICS (6939)
Auroral phenomena (2407)
Cusp
Electric fields (2411)
Energetic particles: precipitating
Energetic particles: trapped
Field-aligned currents and current systems (2409)
Forecasting (1922, 4315, 7924, 7964)
Magnetic reconnection (7526, 7835)
Magnetopause and boundary layers
Magnetosheath
Magnetosphere: inner
Magnetosphere: outer
Magnetosphere interactions with satellites and rings
Magnetosphere/ionosphere interactions (2431)
Magnetospheric configuration and dynamics
Magnetotail
Magnetotail boundary layers
MHD waves and instabilities (2149, 6050, 7836)
Numerical modeling
Planetary magnetospheres (5443, 5737, 6033)
Plasma convection (2463)
Plasma sheet
Plasmasphere
Plasma waves and instabilities (2471)
Polar cap phenomena
Radiation belts
Ring current
Solar wind interactions with unmagnetized bodies
Solar wind/magnetosphere interactions
Magnetic storms and substorms (4305, 7954)
Substorms
Instruments and techniques
General or miscellaneous
MARINE GEOLOGY AND GEOPHYSICS
Back-arc basin processes
Continental shelf and slope processes (4219)
Gas and hydrate systems
Marine magnetics and paleomagnetics (1550)
Marine electromagnetics
Gravity and isostasy (1218, 1222)
Heat flow (benthic)
Hydrothermal systems (0450, 1034, 3616, 4832, 8135, 8424)
Littoral processes
Marine hydrogeology
Marine sediments: processes and transport
Marine seismics (0935, 7294)
Micropaleontology (0459, 4944)
Midocean ridge processes
Ocean drilling
Oceanic hotspots and intraplate volcanism
Oceanic plateaus and microcontinents
Oceanic transform and fracture zone processes
Plate tectonics (8150, 8155, 8157, 8158)
Ophiolites (8140)
Seafloor morphology, geology, and geophysics
Ocean observatories and experiments
Subduction zone processes (1031, 3613, 8170, 8413)
Submarine landslides
Submarine tectonics and volcanism
Submergence instruments: ROV, AUV, submersibles
Instruments and techniques
General or miscellaneous
MATHEMATICAL GEOPHYSICS (0500, 4307, 4314, 4400, 7833)
Fourier analysis (3255)
Instability analysis (4312)
Inverse theory
Numerical approximations and analysis (4260)
Persistence, memory, correlations, clustering (3265, 4313, 7857)
Prediction (3245, 4263, 4315)
Probabilistic forecasting (3238, 4315)
Spatial analysis (0500, 1980, 4319)
Spectral analysis (3205, 3280, 4319)
Stochastic processes (3235, 4468, 4475, 7857)
Time series analysis (1872, 1988, 4277, 4475)
Uncertainty quantification (1873, 1990)
Wavelet transform (3255, 4455)
Wave propagation (0689, 2487, 4275, 4455, 6934)
Instruments and techniques
General or miscellaneous
ATMOSPHERIC PROCESSES
Atmospheric electricity
Balanced dynamical models
Climate change and variability (1616, 1635, 3309, 4215, 4513)
Boundary layer processes
Climatology (1616, 1620, 3305, 4215, 8408)
Clouds and aerosols
Clouds and cloud feedbacks
Convective processes
Data assimilation
General circulation (1223)
Idealized model
Land/atmosphere interactions (1218, 1631, 1843, 4301)
Large eddy simulation
Lightning
Monte Carlo technique
Mesoscale meteorology
Mesospheric dynamics
Model calibration (1846)
Middle atmosphere dynamics (0341, 0342)
North American Monsoon
Numerical approximations and analyses (1849)
Global climate models (1626, 4928)
Ocean/atmosphere interactions (0312, 4301, 4504)
Paleoclimatology (0473, 4900)
Planetary meteorology (5445, 5739)
Polar meteorology
Precipitation (1854)
Radiative processes
Regional modeling (4316)
Remote sensing (4337)
Stratosphere/troposphere interactions
Stratospheric dynamics
Synoptic-scale meteorology
Subgrid-scale (SGS) parameterization
Theoretical modeling (4316)
Thermospheric dynamics (0358)
Tropical convection
Tropical cyclones
Tropical dynamics
Tropical meteorology
Tropopause dynamics
Turbulence (4490)
Acoustic-gravity waves
Tides and planetary waves
Wildland fire model
Instruments and techniques
General or miscellaneous
MINERALOGY AND PETROLOGY
Geochemical modeling (1009, 8410)
Thermodynamics (0766, 1011, 8411)
Reactions and phase equilibria (1012, 8412)
Subduction zone processes (1031, 3060, 8170, 8413)
Mid-oceanic ridge processes (1032, 8416)
Intra-plate processes (1033, 8415)
Hydrothermal systems (0450, 1034, 3017, 4832, 8135, 8424)
Alteration and weathering processes (1039)
Magma chamber processes (1036)
Magma genesis and partial melting (1037)
Mantle processes (1038)
Mineral and crystal chemistry (1042)
Petrography, microstructures, and textures
Experimental mineralogy and petrology
Igneous petrology
Extrusive structures and rocks
Intrusive structures and rocks
Layered magma chambers
Metamorphic petrology
Thermobarometry
Pressure-temperature-time paths
Fluid flow
Ultra-high pressure metamorphism
Ultra-high temperature metamorphism
Meteorite mineralogy and petrology (1028, 6240)
Mineral occurrences and deposits
Planetary mineralogy and petrology (5410)
Sedimentary petrology
Field relationships (1090, 8486)
Instruments and techniques
General or miscellaneous
MINERAL PHYSICS
Creep and deformation
Defects
Elasticity and anelasticity
Electrical properties
Equations of state
High-pressure behavior
NMR, Mossbauer spectroscopy, and other magnetic techniques
Optical, infrared, and Raman spectroscopy
Physical thermodynamics
Shock wave experiments
Surfaces and interfaces
Thermal expansivity
X-ray, neutron, and electron spectroscopy and diffraction
Instruments and techniques
General or miscellaneous
NATURAL HAZARDS
Atmospheric (0370 3322, 3339)
Geological (0742, 4564, 7212, 7280, 8419, 8425, 8426, 8428, 8488)
Hydrological (1810, 1812, 1821)
Oceanic (1641, 4564)
Space weather (2101, 2788, 7900)
Multihazards
Methods (0500, 3200, 4400)
Other (0468, 0702, 6205, 6210)
Analogue modeling
Catastrophe and catastrophe theory (3215)
Extreme events (1817, 3235)
Mathematical and computer modeling (0500, 3200)
Monitoring, forecasting, prediction (1816, 1922, 2722, 3238, 3245, 4263, 7223, 7924)
Physical modeling (0466, 0545, 0798, 1622, 1847, 1952, 3355, 3367)
Precursors
Statistical analysis (1984, 1986)
Spatial modeling (3252, 3255)
Climate impact (1630, 1637, 1807, 8408)
Health impact
Human impact (1834, 7938)
Spatial decision support systems (1918, 6309)
Megacities and urban environment (0345, 0478, 0493)
Exposure
Resilience
Risk (8488)
Sustainable development
Vulnerability
Disaster relief
Disaster resilience
Disaster risk analysis and assessment (6304, 8488)
Disaster risk communication
Disaster management
Economic impacts of disasters
Remote sensing and disasters (1243, 1640, 1855, 3360, 8485)
Disaster policy (6300, 6620)
Disaster mitigation (6309, 7914)
Early warning systems
Emergency management (6344)
Preparedness and planning (6334)
Microzonation and macrozonation
Community management
Emergency response and evacuations (1964)
Recovery and reconstruction after disaster
Contingency planning
International organizations and natural disasters
Interaction between science and disaster management authorities
Sociology of disasters (1974)
Psychology of disasters
Miscellaneous
NONLINEAR GEOPHYSICS (3200, 4307, 6944, 7839)
Bifurcations and attractors
Cascades
Chaos (7805)
Critical phenomena
Complex systems
Emergent phenomena
Fractals and multifractals
Nonlinear differential equations
Nonlinear maps
Nonlinear waves, shock waves, solitons (0689, 2487, 3280, 3285, 4275, 6934, 7851, 7852)
Pattern formation
Phase transitions
Probability distributions, heavy and fat-tailed (3265)
Renormalization group methods
Scaling: spatial and temporal (1872, 1988, 3265, 3270, 4277, 7857)
Self-organized criticality
Self-organization
Turbulence (3379, 4568, 7863)
Instruments and techniques
General or miscellaneous
OCEANOGRAPHY: GENERAL
Analytical modeling and laboratory experiments
Arctic and Antarctic oceanography (9310, 9315)
Benthic boundary layers
Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
Coastal processes
Continental shelf and slope processes (3002)
Coral reef systems (4916)
Descriptive and regional oceanography
Diurnal, seasonal, and annual cycles (0438)
Equatorial oceanography
Estuarine processes (0442)
Limnology (0458, 1845, 4942)
Marginal and semi-enclosed seas
Marine meteorology
Marine pollution (0345, 0478)
Numerical modeling (0545, 0560, 1952)
Ocean acoustics
Ocean data assimilation and reanalysis (3225)
Ocean observing systems
Ocean predictability and prediction (3238, 4315)
Ocean optics (0649)
Physical and chemical properties of seawater
Physical and biogeochemical interactions
Remote sensing and electromagnetic processes (0689, 2487, 3285, 4455, 6934)
Time series experiments (1872, 1988, 3270, 4475)
Upwelling and convergences (4964)
Water masses
Instruments and techniques
General or miscellaneous
OCEANOGRAPHY: PHYSICAL
Air/sea interactions (0312, 3339)
Capillary waves
Coriolis effects
Currents
Decadal ocean variability (1616, 1635, 3305, 4215)
Deep recirculations
Eastern boundary currents
Eddies and mesoscale processes
ENSO (4922)
Fine structure and microstructure
Fronts and jets
General circulation (1218, 1222)
Hydrodynamic modeling
Hydrography and tracers
Ice mechanics and air/sea/ice exchange processes (0700, 0750, 0752, 0754)
Internal and inertial waves
Nearshore processes
Ocean fog
Ocean influence of Earth rotation (1223)
Overflows
Planetary waves
Sea level: variations and mean (1222, 1225, 1641)
Sediment transport (1862)
Surface waves and tides (1222)
Topographic/bathymetric interactions
Tsunamis and storm surges (4302, 4304)
Turbulence, diffusion, and mixing processes (4490)
Upper ocean and mixed layer processes
Western boundary currents
Instruments and techniques
General or miscellaneous
OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL (0460)
Aerosols (0305, 4906)
Analytical chemistry
Anoxic environments (0404, 1803, 4834, 4902)
Benthic processes, benthos (0408)
Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4912)
Carbon cycling (0428)
Chemical speciation and complexation
Chemical tracers
Chemosynthesis
Colloids
Ecological prediction
Ecosystems, structure, dynamics, and modeling (0439)
Food webs, structure, and dynamics (0491)
Gases
Geochemistry
Higher trophic levels
Hydrothermal systems (0450, 1034, 3017, 3616, 8135, 8424)
Hypoxic environments (0404, 4802)
Marine inorganic chemistry (1050)
Microbiology and microbial ecology (0465)
Natural products chemistry
Nutrients and nutrient cycling (0470, 1050)
Marine organic chemistry (0470, 1050)
Oxidation/reduction reactions (0471)
Photochemistry
Photosynthesis
Physical chemistry
Phytoplankton
Population dynamics and ecology
Radioactivity and radioisotopes
Sedimentation (1861)
Sorptive scavenging
Stable isotopes (0454, 1041)
Symbiosis
Trace elements (0489)
Zooplankton
Instruments, sensors, and techniques
General or miscellaneous
PALEOCEANOGRAPHY (0473, 3344)
Abrupt/rapid climate change (1605)
Anthropogenic effects (1803, 4802)
Atmospheric transport and circulation
Aerosols (0305, 4801)
Albedo
Astronomical forcing
Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4805)
Continental climate records
Corals (4220)
Cosmogenic isotopes (1150)
Dendrochronology
El Nino (4522)
Geochemical tracers
Glacial
Global climate models (1626, 3337)
Greenhouse gases
Ice cores (0724)
Insolation forcing
Interglacial
Interhemispheric phasing
Isotopic stage
Limnology (0458, 1845, 4239)
Micropaleontology (0459, 3030)
Milankovitch theory
Paleocene/Eocene thermal maximum
Paleoecology
Palynology
Sea surface temperature
Speleothems
Stadial
Thermohaline
Upwelling (4279)
Instruments and techniques
General or miscellaneous
PHYSICAL PROPERTIES OF ROCKS
Acoustic properties
Fracture and flow
Magnetic and electrical properties (0925)
Microstructure
Permeability and porosity
Plasticity, diffusion, and creep
Thermal properties
Transport properties
Wave attenuation
Instruments and techniques
General or miscellaneous
PLANETARY SCIENCES: ASTROBIOLOGY
Formation of stars and planets
Planetary atmospheres, clouds, and hazes (0343)
Origin of life
Hydrothermal systems and weathering on other planets
Early environment of Earth
PLANETARY SCIENCES: SOLID SURFACE PLANETS
Atmospheres (0343, 1060)
Aurorae and airglow
Composition (1060, 3672)
Erosion and weathering
Glaciation
Gravitational fields (1221)
Heat flow
Hydrology and fluvial processes
Ices
Impact phenomena, cratering (6022, 8136)
Interactions with particles and fields
Interiors (8147)
Ionospheres (2459)
Magnetic fields and magnetism
Magnetospheres (2756)
Meteorology (3346)
Orbital and rotational dynamics (1221)
Origin and evolution
Physical properties of materials
Polar regions
Remote sensing
Rings and dust
Surface materials and properties
Tectonics (8149)
Volcanism (6063, 8148, 8450)
Instruments and techniques
General or miscellaneous
PLANETARY SCIENCES: FLUID PLANETS
Atmospheres (0343, 1060)
Aurorae
Composition (1060)
Gravitational fields (1221)
Interactions with particles and fields
Interiors (8147)
Ionospheres (2459)
Magnetic fields and magnetism
Magnetospheres (2756)
Meteorology (3346)
Orbital and rotational dynamics (1221)
Origin and evolution
Polar regions
Rings and dust
Tidal forces
Tori and exospheres
Instruments and techniques
General or miscellaneous
PLANETARY SCIENCES: COMETS AND SMALL BODIES
Atmospheres (1060)
Aurorae, airglow, and X-ray emission
Composition (1060)
Dust
Erosion and weathering
Gravitational fields (1221)
Ices
Impact phenomena (5420, 8136)
Interactions with solar wind plasma and fields
Comets: dust tails and trails (6210)
Interiors (8147)
Ionospheres (2459)
Magnetic fields and magnetism
Magnetospheres (2756)
Orbital and rotational dynamics
Origin and evolution
Physics and chemistry of materials
Plasma and MHD instabilities (2149, 2752, 7836)
Surfaces
Radiation and chemistry
Volcanism (5480, 8450)
Instruments and techniques
General or miscellaneous
PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS
Asteroids (4308)
Asteroids: satellites
Comparative planetology
Comets (4308, 6023)
Centaurs
Dust
Jovian satellites
Io
Europa
Ganymede
Callisto
Jupiter
Kuiper belt objects
Mars
Martian satellites
Mercury
Meteorites and tektites (1028, 3662)
Meteors
Moon (1221)
Neptune
Neptunian satellites
Triton
Planetary rings
Pluto and satellites
Saturn
Saturnian satellites
Titan
Enceladus
Trans-Neptunian objects
Uranian satellites
Uranus
Venus
Extra-solar planets
Instruments and techniques
General or miscellaneous
POLICY SCIENCES (4338, 7964)
Benefit-cost analysis (4333)
Decision making under uncertainty (1918, 4324, 4339)
Demand estimation
Institutions
Legislation and regulations (6615)
Project evaluation
Regional planning (1880, 4343)
System design
System operation and management (4342)
General or miscellaneous
PUBLIC ISSUES
Funding
Legislation and regulations (6324)
Science policy (0485, 4338)
Workforce
General or miscellaneous
RADIO SCIENCE
Electromagnetic noise and interference
Interferometry (1207, 1209, 1242)
Ionospheric physics (1240, 2400)
Ionospheric propagation (0689, 2487, 3285, 4275, 4455)
Magnetospheric physics (2700)
Nonlinear phenomena (4400, 7839)
Radar astronomy
Radar atmospheric physics (1220)
Radio astronomy
Radio oceanography (1222)
Radio wave propagation
Remote sensing
Signal processing (0674)
Space and satellite communication
Tomography and imaging (7270, 8180)
Waves in plasma (7867)
Instruments and techniques (1241)
General or miscellaneous
SEISMOLOGY
Body waves
Continental crust (1219)
Core (1212, 1213, 8124)
Mantle (1212, 1213, 8124)
Earthquake dynamics (1242)
Earthquake ground motions and engineering seismology (4302)
Earthquake source observations (1240)
Lithosphere (1236)
Seismic monitoring and test-ban treaty verification
Oceanic crust
Paleoseismology (8036)
Earthquake interaction, forecasting, and prediction (1217, 1242, 4315)
Seismicity and tectonics (1207, 1217, 1240, 1242)
Subduction zones (1207, 1219, 1240)
Mid-ocean ridges
Transform faults
Surface waves and free oscillations
Theory
Tomography (6982, 8180)
Volcano seismology (4302, 8419)
Computational seismology
Seismic instruments and networks (0935, 3025)
General or miscellaneous
SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
Celestial mechanics
Chromosphere
Corona
Coronal holes
Coronal mass ejections (2101)
Energetic particles (2114)
Flares
Helioseismology
Magnetic fields
Magnetic reconnection (2723, 7835)
Photosphere
Prominence eruptions
Radio emissions
Solar activity cycle (2162)
Solar and stellar variability (1650)
Solar irradiance
Stellar astronomy
Stellar interiors and dynamo theory
Transition region
Ultraviolet emissions
X-rays, gamma rays, and neutrinos
Instruments and techniques
General or miscellaneous
SPACE PLASMA PHYSICS
Active perturbation experiments
Chaos (4420)
Charged particle motion and acceleration
Discontinuities (2109)
Electrostatic structures
Ionization processes (2423)
Kinetic and MHD theory
Kinetic waves and instabilities
Laboratory studies and experimental techniques
Magnetic reconnection (2723, 7526)
Mathematical and numerical techniques (0500, 3200)
MHD waves and instabilities (2149, 2752, 6050)
Neutral particles (2151)
Nonlinear phenomena (4400, 6944)
Parametric processes
Particle acceleration
Plasma energization
Plasma interactions with dust and aerosols (2461)
Radiation processes
Shock waves (4455)
Solitons and solitary waves (4455)
Spacecraft/atmosphere interactions
Spacecraft sheaths, wakes, charging
Stochastic phenomena (3235, 3265, 4475)
Transport processes
Turbulence (4490)
Wave/particle interactions (2483, 6984)
Wave/wave interactions
Instruments and techniques
General or miscellaneous
SPACE WEATHER (4305)
Geomagnetically induced currents
Engineering for hazard mitigation (4339)
Forecasting (1922, 2722, 4315)
Impacts on technological systems
Impacts on humans (4323)
Ionospheric effects on radio waves
Ionospheric storms (2441)
Magnetic storms (2788)
Models
Policy (2722, 6300)
Satellite drag (1241)
Solar effects
Space radiation environment
General or miscellaneous
STRUCTURAL GEOLOGY
Continental neotectonics (8107)
Diapir and diapirism
Dynamics and mechanics of faulting (8118)
Folds and folding
Fractures and faults
Kinematics of crustal and mantle deformation
High strain deformation zones
Local crustal structure
Mechanics, theory, and modeling
Melanges
Mesoscopic fabrics
Microstructures
Rheology: crust and lithosphere (8159)
Rheology: general (8160)
Rheology: mantle (8162)
Rheology and friction of fault zones (8163)
Pluton emplacement
Paleoseismology (7221)
Regional crustal structure
Remote sensing
Role of fluids
Instruments and techniques
General or miscellaneous
TECTONOPHYSICS
Continental contractional orogenic belts and inversion tectonics
Continental cratons
Continental margins: convergent
Continental margins: divergent (1212, 8124)
Continental margins: transform
Continental neotectonics (8002)
Continental tectonics: compressional
Continental tectonics: extensional (0905)
Continental tectonics: general (0905)
Continental tectonics: strike-slip and transform
Core processes (1213, 1507)
Dynamics and mechanics of faulting (8004)
Dynamics of lithosphere and mantle: general (1213)
Dynamics: convection currents, and mantle plumes
Dynamics: gravity and tectonics
Dynamics: seismotectonics
Earth's interior: composition and state (1212, 7207, 7208, 8105)
Evolution of the Earth (0325)
Heat generation and transport
Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8424)
Impact phenomena (5420, 6022)
Hotspots, large igneous provinces, and flood basalt volcanism
Lithospheric flexure
Obduction tectonics
Ophiolites (3042)
Physics of magma and magma bodies
Planetary interiors (5430, 5724, 6024)
Planetary volcanism (5480, 8450)
Planetary tectonics (5475)
Plate boundary: general (3040)
Plate motions: general (3040)
Plate motions: past (3040)
Plate motions: present and recent (3040)
Rheology: crust and lithosphere (8031)
Rheology: general (1236, 8032)
Rheology: mantle (8033)
Rheology and friction of fault zones (8034)
Stresses: crust and lithosphere
Stresses: deep-seated
Stresses: general
Sedimentary basin processes
Subduction zone processes (1031, 3060, 3613, 8413)
Tectonics and landscape evolution
Tectonics and climatic interactions
Tectonics and magmatism
Tomography (6982, 7270)
Volcanic arcs
Instruments and techniques
General or miscellaneous
VOLCANOLOGY
Geochemical modeling (1009, 3610)
Thermodynamics (0766, 1011, 3611)
Reactions and phase equilibria (1012, 3612)
Subduction zone processes (1031, 3060, 3613, 8170)
Mid-oceanic ridge processes (1032, 3614)
Intra-plate processes (1033, 3615)
Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8135)
Effusive volcanism (4302)
Mud volcanism (4302)
Subaqueous volcanism
Explosive volcanism (4302)
Planetary volcanism (5480, 6063, 8148)
Volcanoclastic deposits
Volcano/climate interactions (1605, 3309, 4321)
Atmospheric effects (0370)
Volcanic gases
Lava rheology and morphology
Magma migration and fragmentation
Eruption mechanisms and flow emplacement
Physics and chemistry of magma bodies
Calderas
Experimental volcanism
Tephrochronology (1145)
Remote sensing of volcanoes (4337)
Field relationships (1090, 3690)
Volcano monitoring (4302, 7280)
Volcanic hazards and risks (4302, 4328, 4333)
Instruments and techniques
General or miscellaneous
GEOGRAPHIC LOCATION
Africa
Antarctica (4207)
Arctic region (0718, 4207)
Asia
Atlantic Ocean
Australia
Europe
Indian Ocean
Large bodies of water (e.g., lakes and inland seas) (0746)
North America
Pacific Ocean
South America
General or miscellaneous
INFORMATION RELATED TO GEOLOGIC TIME
Cenozoic
Neogene
Paleogene
Mesozoic
Cretaceous
Jurassic
Triassic
Paleozoic
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Precambrian
Proterozoic
Archean
General or miscellaneous
GENERAL OR MISCELLANEOUS
Instruments useful in three or more fields
New fields (not classifiable under other headings)
Notices and announcements
Techniques applicable in three or more fields