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Nuclear strikes on hurricanes
Nuclear strikes on hurricanes, also called nuking a hurricane, is a recurring proposal to destroy hurricanes with bombs, rejected by scientists as ineffective and a radioactive fallout hazard.
Nuclear winter
Nuclear winter is the hypothesized severe cooling and darkness that would follow nuclear war, first modeled in a 1983 paper by Turco, Toon, and Sagan's colleagues.
Numerical weather prediction
Numerical weather prediction, also called numerical weather forecasting, is a method in which computers solve the equations governing the atmosphere to predict future weather from current observations.
Nuna (supercontinent)
Nuna, also known as Columbia or Hudsonland, is a hypothesized supercontinent assembled from most of Earth's ancient continental cores between roughly 1.9 and 1.6 billion years ago, preceding Rodinia and Pangaea.
Nunatak
A nunatak (Inuktitut nunataq) is a rocky crag or small mountain surrounded by a glacier or ice sheet, found in Greenland and Antarctica and used to date past ice thickness.
Nutrient criteria
Nutrient criteria are numerical water quality values for total phosphorus, total nitrogen, and response variables like chlorophyll a, set to prevent and assess eutrophic conditions.
Nutrient spiraling
Nutrient spiraling is the cycling of nutrients in streams and rivers, where uptake and mineralization combine with downstream transport to trace a spiral path, formalized in 1981.
NYS Mesonet
The NYS Mesonet is a statewide network of over 200 automated weather stations operated by the University at Albany, established in 2014 with FEMA funding after Superstorm Sandy.
Oasis
An oasis is an area made fertile by freshwater from springs or wells in an otherwise arid region, supporting agriculture, settlement, and trade, such as Egypt's Nile valley.
Obduction
Obduction is the tectonic process by which dense oceanic lithosphere, typically preserved as an ophiolite, is thrust onto lighter continental lithosphere instead of sinking at subduction zones.
Obsidian
Obsidian, also called obsidian rock or dragonglass, is a volcanic glass formed when silica-rich lava cools so fast that crystals cannot form, long prized for razor-sharp tools.
Obukhov length
The Obukhov length, also called the Monin–Obukhov length, is a length scale characterizing stability of the atmospheric surface layer by comparing shear and buoyancy effects on turbulence.
Occluded front
An occluded front, or front occlusion, forms when a faster-moving cold front overtakes a warm front in an extratropical cyclone, signaling the low has reached its mature, decaying stage.
Ocean acidification
Ocean acidification is the ongoing decline in seawater pH caused by the ocean's absorption of human-made carbon dioxide, making the ocean about 30% more acidic since 1750.
Ocean acidification in the Arctic Ocean
Ocean acidification in the Arctic Ocean is the ongoing decrease in seawater pH and carbonate ions caused by carbon dioxide uptake, amplified by cold water, sea ice melt, and freshwater input.
Ocean bottom node (seismic)
An ocean bottom node is an autonomous seismic receiver placed on the seabed to record air-gun energy, offering wider azimuth and cleaner data than towed streamers.
Ocean carbon sink
The ocean carbon sink is the net removal of carbon dioxide from the atmosphere by the ocean, which absorbs 25 to 30 percent of human-made CO2 emissions.
Ocean circulation
Ocean circulation: the wind-driven surface and density-driven deep movement of seawater, including the AMOC, which transports heat, carbon, and nutrients globally and regulates climate; the ocean absorbs over a quarter of carbon emissions and about 93% of excess heat.
Ocean color
Ocean color is the spectral distribution of visible light leaving the sea surface, measured from satellites to track chlorophyll a, phytoplankton biomass, and the ocean's role in the carbon cycle.
Ocean current
An ocean current, also called a sea or marine current, is a continuous stream of seawater driven by wind, density differences, and tides, carrying heat poleward and shaping climate.
Ocean data management and dissemination
Ocean data management and dissemination covers the practices, institutions, and standards for quality-controlling, archiving, and distributing oceanographic data, coordinated through the IODE program of UNESCO's Intergovernmental Oceanographic Commission.
Ocean deoxygenation
Ocean deoxygenation is the loss of dissolved oxygen from the world ocean, driven by warming, altered circulation, and coastal eutrophication; the open ocean has lost about 2% of its oxygen since the 1960s.
Ocean Drilling Program
The Ocean Drilling Program (ODP) was an international scientific partnership, run from 1985 to 2003 aboard the drillship JOIDES Resolution, that cored sediments and crust beneath the ocean basins.
Ocean front
An ocean front is a narrow zone of sharp horizontal change in temperature, salinity, or density, separating two distinct water masses and concentrating pollutants and marine life.
Ocean gyre
An ocean gyre, or oceanic gyre, is a large rotating system of surface ocean currents circling an ocean basin; five subtropical gyres occupy the major oceans.
Ocean heat content
Ocean heat content (OHC) is the total thermal energy stored in the ocean, which absorbs about 93 percent of the excess heat trapped by greenhouse gases.
Ocean mixed layer
The ocean mixed layer is the turbulent uppermost ocean layer, nearly uniform in temperature, salinity, and density, through which the ocean exchanges heat, gas, and momentum with the atmosphere.
Ocean Networks Canada
Ocean Networks Canada (ONC) is a University of Victoria ocean observing facility operating cabled observatories NEPTUNE and VENUS plus Arctic monitoring, delivering free real-time ocean data online.
Ocean Observatories Initiative
The Ocean Observatories Initiative (OOI) is a National Science Foundation-funded network of over 900 ocean sensors in the Atlantic and Pacific, fully operational since 2016 with freely available data.
Ocean tracer
An ocean tracer is a dissolved substance whose measured concentration in seawater reveals the rates, pathways, and time scales of ocean circulation, mixing, and biogeochemical processes, most notably transient tracers such as CFCs.