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May 2024 solar storms
The May 2024 solar storms, known as the Gannon storm, drove the first G5 extreme geomagnetic storm since 2003, with naked-eye aurora visible as far south as Mexico and India.
Mayon
Mayon (Bulkang Mayon), also called Mount Mayon, is the Philippines' most active volcano, a 2,462-meter stratovolcano on Luzon known for its near-perfect symmetrical cone, with eruptions recorded since 1616.
McArthur Forest Fire Danger Index
The McArthur Forest Fire Danger Index (FFDI) is an Australian index of bushfire danger in eucalypt forests, developed by Alan McArthur and used operationally from 1967.
Meager
Meager (Mount Meager Volcanic Complex, Qw'elqw'elústen) is Canada's northernmost Cascade arc volcano in British Columbia; VEI 4 eruption about 2360 years BP, Canada's greatest-threat volcano, major 2010 landslide.
Mean high water
Mean high water is a tidal datum, the average of all high water heights observed over the 19-year National Tidal Datum Epoch used by NOAA.
Mean higher high water
Mean higher high water (MHHW) is a tidal datum averaging the higher of each day's two high tides over a 19-year National Tidal Datum Epoch, used as the reference for coastal flooding.
Mean low water
Mean low water is a tidal datum, the average of all low water heights observed over a 19-year period, used as a reference for charting and coastal legal boundaries.
Mean lower low water
Mean lower low water (MLLW) is the tidal datum, averaged over 19 years, that serves as the chart datum for depths on U.S. coastal nautical charts.
Media coverage of climate change
Media coverage of climate change, also called global warming in the media, is reporting on climate change by newspapers, television, radio, and online media, tracked since 1988.
Medicine Lake Volcano
Medicine Lake Volcano, also known as Medicine Lake Highlands, is a large shield volcano in the Cascade Range of northern California, the largest in the range by volume.
Medieval Warm Period
The Medieval Warm Period, also called the Medieval Climate Anomaly, was an interval of relative warmth in parts of the North Atlantic region from roughly 950 to 1250 CE.
Mediterranean climate
The Mediterranean climate, or dry summer climate, is a temperate climate with wet winters and dry summers, occurring in five regions including the Mediterranean Basin, California, and central Chile.
Mediterranean Oscillation
The Mediterranean Oscillation is an atmospheric teleconnection pattern, a pressure seesaw between the western and eastern Mediterranean basins, measured by an index introduced by Conte and colleagues in 1989.
Mediterranean Outflow Water
Mediterranean Outflow Water is the warm, highly saline water mass formed where dense Mediterranean water exits Gibraltar, mixes in the Gulf of Cádiz, and spreads into the North Atlantic.
Mediterranean Sea
The Mediterranean Sea, also known as the Med, is a semi-enclosed sea between Europe, Africa, and Asia, connected to the Atlantic through the Strait of Gibraltar.
Mediterranean tropical-like cyclone
A Mediterranean tropical-like cyclone, commonly called a medicane, is a small, hurricane-like storm that forms over the Mediterranean Sea one to a few times per year.
Megathrust earthquake
A megathrust earthquake is a great earthquake of moment magnitude 8 or more that ruptures the plate-boundary fault of a subduction zone, including the largest recorded quakes.
Megatsunami
A megatsunami, also known as an iminami, is an unusually large tsunami generated by giant landslides, volcanic flank collapses, or asteroid impacts instead of ordinary earthquakes, with run-ups exceeding 100 m.
Meidob Volcanic Field
Meidob Volcanic Field (Meidob Hills), alkaline volcanic field in western Sudan at the NE end of the Darfur volcanic province; 5,000 km2, nearly 700 vents, 7 Ma to 5 ka activity, last eruption 2950 BCE.
Melanterite
Melanterite is a monoclinic sulfate mineral, ferrous sulfate heptahydrate (FeSO₄·7H₂O), formed mainly by oxidation of pyrite and marcasite in mine workings, and named in 1850 from the Greek for "copperas."
Meliadine mine
The Meliadine mine is a gold mine owned by Agnico Eagle in Nunavut, Canada, 25 km north of Rankin Inlet, which began commercial production in May 2019.
Melt pond
A melt pond is a pool of meltwater that collects on the surface of sea ice, most commonly on Arctic sea ice during summer, where ponds lower albedo and speed melting.
Membrane polarization
Membrane polarization is a mechanism of induced polarization in rocks and soils, in which clay surfaces and narrow pores form ion-selective zones that build up charge-storing ion concentration gradients.
Mendenhall Glacier
Mendenhall Glacier, known in Tlingit as Sitaantaagu, is a 13-mile glacier near Juneau, Alaska, that flows from the Juneau Icefield and has retreated several kilometers since the Little Ice Age.
Mercator projection
The Mercator projection, also known as the Mercator chart, is a cylindrical map projection presented by Gerardus Mercator in 1569, in which lines of constant bearing are straight.
Merchants of Doubt
Merchants of Doubt is a 2010 nonfiction book by Naomi Oreskes and Erik M. Conway documenting how a few scientists sowed doubt on tobacco and climate.
Merian Gold Mine
The Merian Gold Mine is an open-pit gold mine in northeastern Suriname operated by Newmont Suriname, which reached commercial production in October 2016 after construction began in 2014.
Meromixis
Meromixis is the condition of a lake in which the water column never fully mixes, leaving dense bottom water permanently unmixed; the term was coined in 1935 by limnologist Ingo Findenegg.
MERRA-2
MERRA-2, the Modern-Era Retrospective analysis for Research and Applications, Version 2, is a NASA atmospheric reanalysis providing consistent weather and climate data from 1980 to the present.
Mesabi Range
The Mesabi Range, also known as the Mesabi Iron Range, is an iron-mining district in northeastern Minnesota, the largest of Minnesota's three iron ranges, discovered in 1890.