Related by context. Frequent words. (Click for all words.) 61 polar regions 58 polar 57 glaciers 57 ICESat 56 glacial ice 56 IPY 56 magnetosphere 56 atmospheric chemistry 56 polar caps 56 albedo 56 atmospheric circulation 55 volcanism 55 glacial melt 55 crustal 55 mid latitudes 54 permafrost 54 greenhouse warming 54 landforms 54 melting permafrost 54 mountain glaciers 54 troposphere 53 Tibetan Plateau 53 polar ice 53 glacier 53 plate tectonics 53 NSIDC 52 water vapor 52 astrophysical 52 Greenland Ice 51 Antarctic Peninsula 51 glaciation 51 Earth Observing 51 Greenland ice 51 tectonics 51 oceanic 51 Permafrost 50 Antarctica 50 Arctic 50 landmasses 50 oceans 50 glaciologists 50 circumpolar 50 CloudSat 50 subsurface 50 Antarctic ice 50 arctic 50 Serreze 50 Antarctic Ice 50 cometary 50 gas hydrates 50 atmospheric 49 heliosphere 49 atmospheric sciences 49 ozone depletion 49 Arctic Ocean 49 atmospheric carbon dioxide 49 meltwater 49 decadal 49 glacier melt 49 Earth crust 49 comet nucleus 49 convective 49 ejecta 49 subduction zones 49 ionosphere 49 planetary science 49 anthropogenic climate 48 equatorial regions 48 seamounts 48 Antarctic 48 biosphere 48 dynamical 48 Envisat 48 moon Europa 48 olivine 48 boreal 48 Planetary Laboratory 48 geologically active 48 THEMIS 48 greenhouse gas concentrations 48 anthropogenic 48 astronomical observations 48 earth crust 48 Saturn rings 48 Martian surface 47 atmospheric CO2 47 planetary sciences 47 geologic 47 planetary 47 marine ecosystems 47 biota 47 Saturn moon 47 geomagnetic field 47 outer planets 47 volcanic activity 47 planetary scientist 47 outgassing 47 magmatic 47 aerosols 47 refreezing 46 Saturn moons