751 articles
R/V Neil Armstrong
R/V Neil Armstrong (AGOR-27) is an American Ocean Class research vessel owned by the US Navy and operated by Woods Hole Oceanographic Institution from Woods Hole, Massachusetts.
R/V Polarstern
R/V Polarstern is a German research icebreaker operated by the Alfred Wegener Institute from Bremerhaven since 1982, working alternately in the Antarctic and Arctic and best known for the MOSAiC drift expedition.
R/V Roger Revelle
R/V Roger Revelle is a Global Class oceanographic research vessel owned by the U.S. Navy and operated by Scripps Institution of Oceanography, delivered in 1996 and named for the former Scripps director Roger Revelle.
R/V Sally Ride
R/V Sally Ride is a Navy-owned oceanographic research ship operated by Scripps Institution of Oceanography, delivered in 2016 and named for the first American woman in space.
R/V Sikuliaq
R/V Sikuliaq is a 261-foot, global-class oceanographic research vessel owned by the National Science Foundation and operated by the University of Alaska Fairbanks from Seward.
Radar altimetry
Radar altimetry is a satellite remote sensing technique that times microwave pulses to measure sea surface, ice, and land heights, underpinning sea level monitoring and oceanography.
Radius of influence
The radius of influence of a pumping well is the maximum distance up to which pumping significantly affects the aquifer, a concept used in wellhead protection and permitting.
Raised bog
A raised bog is an ombrotrophic peatland, a dome of peat raised above the groundwater by its own growth, fed only by rain, acidic, and dominated by Sphagnum peat mosses.
Rajendra Singh (राजेन्द्र सिंह)
Rajendra Singh (राजेन्द्र सिंह), born 1959, is an Indian water conservationist known as the "Waterman of India" who leads rainwater harvesting and river rejuvenation in rural Rajasthan.
RAPID array
The RAPID array, also known as the RAPID-MOCHA-WBTS array, is a system of ocean moorings across the Atlantic at 26.5°N that has continuously measured the strength of the Atlantic Meridional Overturning Circulation since 2004.
Rating curve
A rating curve is the empirical relation between water level and discharge at a stream gauging station, used to turn continuous stage records into continuous river discharge records.
Rational method (hydrology)
The rational method is an empirical hydrology formula, developed by Thomas Mulvany in 1850, that estimates peak runoff as the product of drainage area, runoff coefficient, and rainfall intensity.
Ravi River
The Ravi River, known in Vedic Sanskrit as Parushni and to Greek writers as Hydraotes, is a transboundary river of the Indus basin and one of the five rivers of the Punjab.
Reactive transport model
A reactive transport model is a numerical model that couples fluid flow, solute transport, and chemical reactions in porous or fractured subsurface media, applied to CO₂ storage and remediation.
Red Sea
The Red Sea is a long, narrow ocean basin between northeastern Africa and the Arabian Peninsula, among the world's warmest and saltiest seas and a critical global shipping route.
Redoxcline
A redoxcline is the layer in a lake or basin where redox conditions change sharply with depth, separating oxygenated water above from anoxic water or sediment below.
Reference conditions (Water Framework Directive)
Reference conditions under the EU Water Framework Directive are the near-natural values for surface water quality elements, serving as the benchmark for classifying high ecological status.
Refractory dissolved organic carbon
Refractory dissolved organic carbon, or rDOC, is the ocean's dissolved organic carbon that resists microbial degradation, persisting for millennia and totaling about 640 Pg C.
Regulated river
A regulated river is one whose flow is largely controlled by major man-made structures such as dams and weirs, so water can be released from upstream storage on demand.
Remotely operated underwater vehicle
A remotely operated underwater vehicle, or ROV, is a tethered underwater robot piloted in real time from a surface ship, first developed by the U.S. Navy in the 1960s.
Research vessel
A research vessel, also called a research ship or oceanographic research ship, is a specialized ship carrying laboratories, sensors, and facilities for oceanographic research at sea.
Residual amount of water
Residual amount of water (residual flow): the flow left in a river below a dam or water take to sustain ecosystems, also called minimum, instream, or environmental flow; key in hydropower reduced flow stretches like Belo Monte.
Residual circulation
Residual circulation is the net large-scale ocean overturning flow, the sum of Eulerian-mean and eddy-induced circulation, and it transports heat, carbon, and nutrients across the Southern Ocean.
Return period
A return period, or recurrence interval, is the average time in years between hydrologic events of a given size, such as a flood exceeding a set discharge.
Rhumb line
A rhumb line, also called a loxodrome, crosses every meridian at the same angle, letting a ship or aircraft hold a constant bearing; it appears straight on a Mercator chart.
Richards equation
Richards equation is the nonlinear partial differential equation describing water movement in unsaturated porous media, formulated by Lorenzo A. Richards in his 1931 paper in Physics.
Rip current
A rip current is a strong, narrow flow of water moving away from shore through the surf zone, and the leading cause of death at surf beaches.
Rip tide
A rip tide, also called a tidal rip, is a strong current formed by tidal water moving swiftly through an inlet or estuary mouth, distinct from a rip current.
River continuum concept
The river continuum concept (RCC) is a 1980 theory in stream ecology holding that rivers show a continuous gradient of conditions from headwaters to mouth, producing predictable changes in communities.
Robert FitzRoy
Robert FitzRoy was a British naval officer who commanded HMS Beagle on the voyage carrying Charles Darwin and founded the Met Office, issuing the first public weather forecasts.