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Shield (geology)
A shield, or continental shield, is a large exposed area of Precambrian crystalline rock forming the stable core of a continent, as in the Canadian Shield.
Shield volcano
A shield volcano, or lava shield, is a broad, gently sloping volcano built of fluid basaltic lava flows, named for a warrior's shield lying flat.
Shiga (landform)
Shiga (志賀, Shiga-Kogen) is an andesitic shield-volcano complex in Nagano and Gunma, Japan, north of Kusatsu-Shirane; reclassified as active with eruptions about 6,400 and 400 years ago.
Shipping Forecast
The Shipping Forecast is a marine weather bulletin for the sea areas around the British Isles, produced by the Met Office and broadcast on BBC Radio 4 since 1924.
Ships of opportunity
Ships of opportunity are ordinary commercial, cruise, fishing, or research vessels that carry scientific instruments on their normal routes, turning regular trade lines into platforms for ocean and climate observation since the 1950s.
Shlomo P. Neuman
Shlomo P. Neuman, also known as Shlomo Peter Neuman, is a hydrogeologist and Regents Professor Emeritus at the University of Arizona, elected to the National Academy of Engineering in 1992.
Shoreline extraction
Shoreline extraction is the automated mapping of the land-water boundary from satellite imagery, used for coastal change monitoring, typically achieving about 10 m horizontal accuracy at microtidal sites.
Short baseline acoustic positioning
Short baseline acoustic positioning is an underwater positioning technique with transducers mounted on a vessel's hull, developed in the 1960s and used to track ROVs, rigs, and the 1963 search for USS Thresher.
Short-lived climate pollutant
A short-lived climate pollutant (SLCP) is an air pollutant that warms the climate for days to decades, chiefly methane, black carbon, tropospheric ozone, and HFCs.
Shortwave radiation
Shortwave radiation is the electromagnetic radiation emitted by the Sun, roughly 0.1 to 5 micrometers covering ultraviolet, visible, and near-infrared light, and is the primary energy input to Earth's climate system.
Shortwave trough
A shortwave trough, also simply called a shortwave, is a disturbance in the mid or upper atmosphere that induces upward motion ahead of it, often aiding thunderstorm development.
Shrinkage of Lake Chad
The shrinkage of Lake Chad is the loss of about 90 percent of the lake's surface area from the 1960s to the 1990s, with recent refilling since 2000.
Shungite (шунгит)
Shungite (шунгит) is a black, noncrystalline, carbon-rich mineraloid rock from Karelia, Russia, containing about 98 percent carbon, named after the village of Shunga and used in water treatment.
Siberian High
The Siberian High, also called the Asiatic High, is a semi-permanent anticyclone of cold air that forms each winter over Eurasia, centered near Lake Baikal and northern Mongolia.
Siberian Traps
The Siberian Traps (Сибирские траппы) is a large igneous province in Siberia whose eruptions around 252 million years ago likely triggered the end-Permian mass extinction.
Siboga Expedition
The Siboga Expedition was a Dutch oceanographic expedition aboard H.M. Siboga, led by Max Weber, that surveyed the seas of the Dutch East Indies in 1899 and 1900.
Side-scan sonar
Side-scan sonar is a sonar technique that transmits sound pulses sideways from a towed or vehicle-mounted device, building acoustic images of the seafloor rather than depth maps.
Siderite
Siderite, also called spathic iron, is a brownish iron carbonate mineral, FeCO3, in the calcite group, used as a minor iron ore and common in sedimentary iron formations.
Significant wave height
Significant wave height (Hs, also SWH) is the mean height of the highest one third of waves, the standard measure of sea state in forecasts and offshore engineering.
Sillimanite
Sillimanite is an aluminum silicate mineral, Al₂SiO₅, occurring as white needles in high-grade metamorphic rocks; it is one of three polymorphs with kyanite and andalusite and is Delaware's state mineral.
Silt
Silt is granular material with particle sizes between sand and clay, typically 0.004 to 0.0625 mm in the Wentworth scale, forming fertile silt loams and wind-deposited loess such as China's Loess Plateau.
Siltstone
Siltstone is a clastic sedimentary rock made predominantly of silt-sized grains, defined by the USGS as indurated silt with the texture of shale but lacking its fine lamination or fissility, and finer than sandstone.
Silurian
The Silurian is a geologic period of the Paleozoic Era between the Ordovician and Devonian, established by Roderick Murchison in the 1830s from Welsh rocks.
Silurian hypothesis
The Silurian hypothesis is a 2018 thought experiment by Gavin Schmidt and Adam Frank asking whether a prehuman industrial civilization would leave traces detectable today in the geological record.
Simoom
Simoom (Arabic: سموم, samūm, "poison wind"), also spelled simoon or samoom, is a hot, dry, dust-laden desert wind of the Sahara, the Levant, and Arabia, briefly reaching 54 °C.
Sinabung
Sinabung (Gunung Sinabung) is a 2,460 m stratovolcano in Karo Regency, North Sumatra, Indonesia, dormant about 400 years before its 2010 eruption, then erupting 2013–2021 with deadly dome-collapse pyroclastic flows, and re-erupting 31 August 2026.
Sinemurian
The Sinemurian is the second stage of the Early Jurassic, spanning roughly 199.5 to 192.9 million years ago, defined by a boundary stratotype on the coast of southwest England.
Singkut
Singkut is a Quaternary volcanic caldera in North Sumatra, Indonesia (GVP 261070, Sunda Arc), also known through its cone Sibayak. It formed ~44 ka in a VEI 6 eruption (~26 km³ DRE), last erupted in 1881, hosts Berastagi and the Sibayak geothermal field, and rises to 2,181 m.
Single Model Large Ensemble
A single model large ensemble, formally a single-model initial-condition large ensemble (SMILE), is a set of many climate simulations run with one climate model under one forcing scenario.
Sirocco
The sirocco, also called jugo on the Adriatic, is a hot, dusty wind from the Sahara that crosses the Mediterranean and brings humid, stormy weather to southern Europe.