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Time reversal imaging
Time reversal imaging is a wavefield method that reverses recorded signals and propagates them back through a medium model, refocusing energy on the original source or scatterer.
Timeline of glaciation
The timeline of glaciation, or list of ice ages, covers Earth's five major glacial periods, from the Huronian glaciation 2.4 billion years ago to the ongoing Quaternary.
Timeline of the 2026 Pacific hurricane season
The timeline of the 2026 Pacific hurricane season covers an exceptionally active, El Niño-driven season with 24 named storms, record accumulated cyclone energy, and Hurricane Polo's Category 5 record.
Tipping element
A tipping element is a large-scale component of the Earth system, such as an ice sheet, that can shift into a different state once a critical threshold is passed.
Tipping points in the climate system
Tipping points in the climate system are critical thresholds beyond which parts of the Earth system, such as the AMOC, ice sheets, and coral reefs, reorganize abruptly and often irreversibly.
Titanite
Titanite, better known in the gem trade as sphene, is a calcium titanium nesosilicate mineral, CaTiSiO₅, forming wedge-shaped crystals and prized as a gem with fire exceeding diamond's dispersion.
Toarcian Oceanic Anoxic Event
The Toarcian Oceanic Anoxic Event, also called the Jenkyns Event, was an episode of global warming and ocean deoxygenation about 183 million years ago in the Early Jurassic.
Tobermorite
Tobermorite is a rare hydrated calcium silicate mineral named for Tobermory on the Isle of Mull, Scotland, first described there in 1880 by M. F. Heddle.
TOGA COARE
TOGA COARE was a multinational field campaign of the World Climate Research Programme that studied ocean–atmosphere coupling over the western Pacific warm pool in 1992 and 1993.
Toh, Tarso
Tarso Tôh (Toh, Tarso) is a Pleistocene-to-Holocene basaltic volcanic field in the NW Tibesti Range, Chad, with about 150 scoria cones, two maars, and Begour maar dated at 8300 ± 300 years.
Tolbachik
Tolbachik (Tolbachik volcanic massif) is a basaltic volcano at the southern end of the Klyuchevskoy group, Kamchatka, Russia, made of Ostry and Plosky Tolbachik stratovolcanoes and the Tolbachinsky Dol cone field; site of the 1975–76 Great Tolbachik Fissure Eruption and the 2012–13 fissure eruption.
Tom Skilling
Tom Skilling is an American broadcast meteorologist who was WGN-TV's chief meteorologist in Chicago from 1978 to 2024, also known for the Chicago Tribune weather page and Fermilab tornado seminars.
Tomasz Schafernaker
Tomasz Schafernaker is a Polish-British meteorologist and BBC weather presenter, born in Gdańsk in 1979, and the UK's favorite weather presenter in a 2017 poll.
Tonalite
Tonalite is a coarse-grained plutonic igneous rock consisting of quartz and plagioclase, usually with biotite and amphibole, and little alkali feldspar; it is named after Tonale Pass in the Alps.
Tonian
The Tonian is the first and longest period of the Neoproterozoic Era, from 1000 to about 720 million years ago, following the Stenian and preceding the Cryogenian.
Top-down control
Top-down control is the regulation of a food web by predators and grazers, notably zooplankton grazing on phytoplankton in lakes, contrasted with bottom-up nutrient control.
Topaz
Topaz, sold in varieties such as Swiss Blue Topaz, is a hard, fluorine-bearing silicate mineral prized as a gemstone in colors from colorless to imperial orange-red.
TOPEX/Poseidon
TOPEX/Poseidon was a joint NASA and CNES satellite mission launched in 1992 that used radar altimetry to measure sea-surface height across the global ocean, beginning the precise satellite record of sea-level rise.
TOPMODEL
TOPMODEL, a physically based semi-distributed rainfall-runoff model proposed by Keith Beven and Mike Kirkby in 1979, predicts streamflow using a topographic index and remains widely used in hydrology.
Topographic prominence
Topographic prominence, also called relative height or autonomous height, measures a summit's independence: how far it rises above the lowest col on the highest ridge to higher ground.
Topographic wetness index
The topographic wetness index (TWI) is a terrain-derived quantity, ln(a/tanβ), combining upslope contributing area and slope, developed by Keith Beven and M. J. Kirkby in 1979.
Topography
Topography is the configuration of a surface, usually the Earth's land surface and sea floor, describing elevation, relief, slope, landforms, and human-made features, classically shown with contour lines on topographic maps.
Topsoil
Topsoil, also known as surface soil, is the uppermost and most fertile soil layer, holding most organic matter and plant roots, and the part most lost to erosion.
Toquepala
Toquepala is an open-pit porphyry copper-molybdenum mine in the Tacna Region of southern Peru, operated by Southern Copper Corporation since 1960, with concentrate treated at its Ilo smelter.
Torleite Formation
Torleite Formation: Upper Jurassic (late Kimmeridgian, ~156–151 Ma) limestone formation in Bavaria, Germany, part of the Weißjura Group and Solnhofen limestones; oldest Solnhofen Archipelago fossil sites, yielding Cricosaurus, Spathagnathus, and Solnhofia.
Tornadic vortex signature
A tornadic vortex signature is a Doppler radar velocity signature of a tornado, first detected at Union City, Oklahoma, in 1973 and used by the National Weather Service since the 1990s.
Tornado
A tornado is a violently rotating column of air extending from a thunderstorm to the ground, with about 1,000 reported in the United States in an average year.
Tornado Alley
Tornado Alley, also called the Tornado belt, is the region of the central United States, centered on the Great Plains, with the highest tornado occurrence.
Tornado and Severe Weather Statement
The Severe Weather Statement (SVS) is a National Weather Service text product issued to update, cancel, correct, or announce the expiration of an active Tornado or Severe Thunderstorm Warning.
Tornado climatology
Tornado climatology is the statistical description of where, when, and how often tornadoes occur, built from historical reports; the United States records the most, averaging about 1,200 per year.