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History of Earth
The history of Earth covers the planet's roughly 4.54 billion years of change, from its formation and the Moon-forming impact to the rise of oxygen and life.
History of tornado research
History of tornado research is the development of tornado science from the first statistics in the 1880s to the 1948 Tinker forecast, radar detection, the Fujita scale, and VORTEX.
History of weather forecasting
The history of weather forecasting runs from local proverbs and barometers to telegraph weather maps, the Bergen school's 1921 polar-front theory, and numerical prediction on electronic computers from 1950.
History of weather observation
The history of weather observation traces how regular, comparable measurement of atmospheric conditions grew from manuscript records into instrument networks, telegraph-based forecasting, and internationally standardized national weather services.
Histosols
Histosols, commonly called bogs, moors, peats, or mucks, are soils formed in thick deposits of decaying plant material with no permafrost, one of the twelve USDA soil orders.
HMS Dolphin (1751)
HMS Dolphin was a 24-gun Royal Navy frigate, built in 1751, and the first ship known to sail around the world twice, under Byron and Wallis.
HMS Endeavour
HMS Endeavour, originally the Earl of Pembroke, was a British collier sailed by James Cook from 1768 to 1771 for scientific discovery, later serving as the transport Lord Sandwich.
HMS Erebus (1826)
HMS Erebus was a Royal Navy bomb vessel, launched in 1826, that carried James Clark Ross to Antarctica and was lost with Franklin's 1845 Northwest Passage expedition.
HMS Protector (A173)
HMS Protector is the Royal Navy's only icebreaker and ice patrol ship, a Norwegian vessel commissioned in 2013 that surveys Antarctic waters, supports research stations, and reached farther north than any Royal Navy ship in 2021.
Hochschild Mining
Hochschild Mining plc is a London-listed precious metals mining company producing silver and gold in South America, rooted in a trading group founded in 1911.
Hockey stick graph
The hockey stick graph is a reconstruction of Northern Hemisphere mean temperature over the past millennium, showing 900 years of gradual decline followed by a sharp twentieth-century rise.
Hodograph
A hodograph, also called a hodogram, is a plot of horizontal wind at successive heights, representing the vertical wind profile; meteorologists use its curve to judge storm types and rotation.
Holdridge life zones
Holdridge life zones are a climate classification system naming regions by the vegetation their climate can support, proposed by Leslie Holdridge in 1947 and still used for mapping.
Hollow Earth
The Hollow Earth theory, or Hohlweltlehre, holds that Earth is hollow with habitable inner worlds; proposed by Edmond Halley, it was refuted by geophysics and survives in fiction.
Holocene
The Holocene, also known as the Holocene epoch, is the current geological epoch, beginning 11,700 years ago with warming that ended the Younger Dryas and divided since 2018 into the Greenlandian, Northgrippian, and Meghalayan stages.
Homogeneous freezing
Homogeneous freezing is the spontaneous freezing of a supercooled liquid droplet without a solid particle, occurring below about −38 °C and driving ice formation in cirrus clouds.
Hondol
Hondol (Hondolen), village in Certeju de Sus, Hunedoara County, Romania, in the Metaliferi Mountains; Roman-era gold mine (RAN 89286.03) and the Coranda-Hondol Au-Ag deposit, about 4.8 Moz at 1.4 g/t Au, mined until 2006.
Hong Kong Observatory
The Hong Kong Observatory (HKO), established in 1883, is the government department of Hong Kong responsible for weather forecasting, tropical cyclone warning signals, radiation monitoring, and the Hong Kong time standard.
Hong Kong tropical cyclone warning signals
The Hong Kong tropical cyclone warning signals, known as typhoon signals, are numbered warnings from the Hong Kong Observatory using signals 1, 3, 8, 9, and 10.
Hoodoo (geology)
A hoodoo, also called an earth pillar or fairy chimney, is a tall, thin rock spire left by erosion. The most famous ones stand in Bryce Canyon, Utah.
Hook echo
A hook echo is a hook-shaped region of radar reflectivity in supercell thunderstorms, formed when precipitation wraps around the rotating mesocyclone, and a key indicator in tornado warning decisions.
Hope Bay
Hope Bay is a gold mining and exploration property in the Kitikmeot region of mainland Nunavut, Canada, owned by Agnico Eagle, which approved a construction decision in May 2026.
Hope Diamond
The Hope Diamond, or Le Bijou du Roi, is a 45.52-carat deep grayish-blue diamond cut from the stolen French Blue and displayed at the Smithsonian since 1958.
Horizontal-to-vertical spectral ratio
The horizontal-to-vertical spectral ratio (HVSR) is a single-station seismological method that estimates a site's fundamental resonance frequency from ambient vibration or earthquake recordings using one three-component seismometer.
Horn River Basin
The Horn River Basin is an unconventional shale gas play in northeastern British Columbia, Canada, home to the first modern Canadian shale gas production in 2006.
Hornblende
Hornblende is a root-name group of dark green to black calcic amphibole minerals, documented by Abraham Gottlieb Werner in 1789, found in rocks such as granite, diorite, gabbro, and schist.
Horse latitudes
The horse latitudes, also called the subtropical ridge, are subtropical high-pressure belts over the oceans near 30°–35° latitude, known for calm winds, hot dry weather, and nearby deserts like the Sahara.
Hot desert climate
The hot desert climate, Köppen code BWh, is an arid climate with mean annual temperature at or above 18 °C, covering roughly 16% of global land area.
Hotspot (geology)
A hotspot is a volcanic region, usually far from plate boundaries, where magma rises from a fixed source, leaving trails of volcanoes like Hawaii, Iceland, and Yellowstone.
HSPF (hydrology)
HSPF (Hydrological Simulation Program–FORTRAN) is a US EPA watershed model that continuously simulates runoff and water quality, recommended for complex TMDL studies and distributed with BASINS.