751 articles
Microbial food web
The microbial food web is the portion of aquatic food webs made up of bacteria, archaea, protists, and viruses that recycle nutrients and dissolved organic matter.
MIKE 11
MIKE 11 is a one-dimensional river modeling software package developed by the Danish Hydraulic Institute (DHI) for simulating water levels, flows, and water quality in rivers and estuaries.
Mild-slope equation
The mild-slope equation, derived by J. C. W. Berkhoff in 1972, is an elliptic partial differential equation describing water waves over slowly varying seabeds, widely used in coastal engineering.
Mixed layer
The mixed layer, also called the isothermal layer, is the turbulent upper ocean where wind and cooling make temperature, salinity, and density nearly uniform, typically tens of meters deep.
Mixing regime
A mixing regime is the annual pattern of vertical mixing and thermal stratification in a lake, classified by how often and how completely its water circulates each year.
Monterey Bay Aquarium Research Institute
The Monterey Bay Aquarium Research Institute (MBARI) is a non-profit oceanographic research center in Moss Landing, California, founded by David Packard in 1987 to advance marine science and technology.
Mooring (oceanography)
An oceanographic mooring is a anchored line with a surface or subsurface buoy and attached instruments that measure ocean conditions at one fixed station continuously, for months to years.
Morphodynamics
Morphodynamics is the study of the mutual adjustment of topography and fluid dynamics involving sediment transport, a feedback loop that shapes shores, estuaries, riverbeds, and dunes.
MOSAiC expedition
MOSAiC was an international Arctic expedition in which the German icebreaker Polarstern drifted frozen in sea ice from 2019 to 2020, studying the Arctic climate.
Moskstraumen
Moskstraumen, also called Moskenesstraumen, is a strong tidal current and maelstrom in the Lofoten archipelago of Nordland, Norway, running between Lofotodden and the island Mosken; it inspired Poe's "A Descent into the Maelström".
MSWEP
MSWEP (Multi-Source Weighted-Ensemble Precipitation) is a global gridded precipitation dataset merging gauge, satellite, and reanalysis data, with version 3 offering hourly, 0.1° estimates from 1979.
MT3DMS
MT3DMS is a modular three-dimensional multi-species solute transport model that simulates contaminant advection, dispersion, and reactions in groundwater, coupled with the USGS flow model MODFLOW.
Multi-year ice
Multi-year ice (MYI) is sea ice that has survived at least one summer melt season, making it the oldest and thickest sea ice at 4 to 5 meters.
Multibeam bathymetry
Multibeam bathymetry is a sonar mapping method in which a hull-mounted echosounder sends a fan of acoustic beams, yielding hundreds of depth soundings per ping for charting underwater terrain.
Multibeam echosounder
A multibeam echosounder is a sonar instrument that measures water depth and seafloor character by sending many acoustic beams in a fan-shaped swath, returning bathymetry and backscatter.
Nash cascade
The Nash cascade is a hydrological model proposed by J. E. Nash in 1957 that routes rainfall through a series of linear reservoirs to derive the instantaneous unit hydrograph.
Nash–Sutcliffe model efficiency coefficient
The Nash–Sutcliffe model efficiency coefficient, or NSE, is a hydrology metric introduced by Nash and Sutcliffe in 1970 that measures how well simulated streamflow matches observations.
National hydrographic services and their surveyors
National hydrographic services are government agencies that survey a country's waters and produce its nautical charts, coordinated by the International Hydrographic Organization, with surveyors trained under IHO-recognized programs.
National Institute of Hydrology (India)
The National Institute of Hydrology (NIH; राष्ट्रीय जलविज्ञान संस्थान) is India's autonomous hydrology research society, established in 1978 and headquartered at Roorkee, Uttarakhand, under the Ministry of Jal Shakti.
National Institute of Oceanography, India
The National Institute of Oceanography, also known as the Indian National Institute of Oceanography, is an autonomous research institute of CSIR in Goa, India, established in 1966.
National Institute of Water and Atmospheric Research
The National Institute of Water and Atmospheric Research (NIWA) was a New Zealand Crown Research Institute, established in 1992, that researched freshwater, oceans, the atmosphere, and climate.
National Oceanography Centre
The National Oceanography Centre (NOC) is the United Kingdom's lead research institution for marine science, based in Southampton and Liverpool and running the research ships Discovery and James Cook.
National traditions in oceanography
National traditions in oceanography are the characteristic ways countries organize the study of the sea through institutions, expeditions, funding, and training, compared across the United States, the Soviet Union, India, and France.
Natural flow regime
The natural flow regime is the characteristic pattern of streamflow in a river under natural conditions, defined by the magnitude, frequency, duration, timing, and rate of change of flows.
Nautical Almanac
The Nautical Almanac is an annual ephemeris published jointly by the US and UK Nautical Almanac Offices, giving mariners data for celestial navigation with a sextant.
Nautical chart
A nautical chart, also called a marine or navigation chart, is an official government-issued map for marine navigation, showing depths, hazards, and aids to seafarers.
Naval Oceanographic Office
The Naval Oceanographic Office (NAVOCEANO), renamed from the U.S. Navy Hydrographic Office in 1962, is the Navy's principal oceanographic command, based in Mississippi and tracing its origins to 1830.
Neap tide
A neap tide is a moderate tide occurring twice each lunar month, at the Moon's first and third quarters, when the Sun and Moon are at right angles to each other.
Net ecosystem production
Net ecosystem production (NEP) is the difference between gross primary production and ecosystem respiration in an ecosystem, commonly measured in lakes with the diel oxygen technique.
Neuston
Neuston is the community of organisms living at, on, or immediately below the air-water interface of oceans, lakes, and ponds, a term introduced by Einar Naumann in 1917.