Earth sciences

Barotropic instability

Barotropic instability is a fluid-dynamical instability of horizontally sheared flow in which disturbances draw kinetic energy directly from the background shear, contrasting with baroclinic instability.

Barremian

The Barremian is the fourth stage of the Early Cretaceous epoch, spanning roughly 126 to 121 million years ago and following the Hauterivian before the Aptian.

Barren Island (Andaman Islands)

Barren Island is an uninhabited volcanic island in the Andaman Sea, about 135 km from Port Blair, and the site of India's only active volcano.

Barrier layer (oceanography)

A barrier layer in oceanography is a nearly isothermal water layer between the mixed layer and the thermocline, kept in place by a salinity gradient and limiting surface heat exchange.

Bartonian

The Bartonian is a geologic stage and age of the middle Eocene epoch, spanning 41.03 to 37.71 million years ago and named after Barton-on-Sea, Hampshire, England.

Basalt

Basalt, or basaltic rock, is a dark, fine-grained volcanic igneous rock with 45 to 53 percent silica that forms most lava flows and the oceanic crust.

Base level

Base level is the lowest elevation to which a stream can erode its bed, a fundamental concept in fluvial geomorphology defined by John Wesley Powell in 1875.

Baseflow

Baseflow (also written base flow) is the portion of streamflow supplied by groundwater discharge and other slowly released stored water, sustaining rivers between storms and through dry seasons.

Baseflow recession

Baseflow recession is the decline of streamflow during dry periods, when groundwater and subsurface storage sustain the river, and it is used to estimate low flows and recharge.

Baseflow separation

Baseflow separation is a hydrological technique that splits a streamflow hydrograph into sustained baseflow and rapid quickflow, summarized by the baseflow index, the ratio of baseflow volume to total streamflow volume.

Baseline Surface Radiation Network

The Baseline Surface Radiation Network (BSRN) is a global network of stations measuring surface solar and infrared radiation with high accuracy, operating since 1992 under the World Climate Research Programme.

Basin modeling

Basin modeling, also spelled basin modelling, is a numerical simulation method reconstructing a sedimentary basin's burial, thermal, and hydrocarbon generation and migration history to predict petroleum system evolution.

Bastnäsite

Bastnäsite, also spelled bastnaesite, is a rare-earth fluorocarbonate mineral and main ore of rare earths at Mountain Pass, California, and Bayan Obo, China; unlike monazite, it carries little thorium.

Bathymetry

Bathymetry, also known as seafloor mapping, is the study of the depths and shapes of underwater terrain, measured mainly with echo sounders and mapped with depth contours called isobaths.

Bathymetry mapping

Bathymetry mapping is the measurement and charting of seafloor depth, done from ships with sonar, from aircraft and satellites with lidar, or from satellites through gravity and optical methods.

Bathyscaphe

A bathyscaphe is a free-diving deep-submergence vehicle, invented by Auguste Piccard, using a gasoline-filled float for buoyancy; the Trieste carried the first humans to the ocean's deepest point in 1960.

Bathysphere

The Bathysphere was a tethered spherical submersible used by William Beebe and Otis Barton off Bermuda in the 1930s, reaching a record 923 meters in 1934.

Bazhenov Formation

The Bazhenov Formation (баженовская свита) is an organic-rich siliceous marine shale covering over 1 million km² in the West Siberian Basin as the world's largest shale oil resource.

BBC Weather

BBC Weather, also known as BBC Weather Centre, is the BBC's weather forecasting service, broadcasting forecasts on television, radio, online, and its app since its first radio forecast in 1922.

BCC-CSM

BCC-CSM (Beijing Climate Center Climate System Model) is a fully coupled climate model developed by the Beijing Climate Center of the China Meteorological Administration, used for CMIP5 and CMIP6 and operational forecasting.

Beam tomography

Beam tomography is a wave-propagation imaging method using beams of finite width, used in seismology to image the Earth's crust and mantle and in helioseismology to image the Sun's interior.

Beaufort High

The Beaufort High, also called the Beaufort Sea High, is a quasi-stationary high-pressure system over the Beaufort Sea north of Alaska whose winds drive the Beaufort Gyre.

Bedford Institute of Oceanography

The Bedford Institute of Oceanography, established in 1962 in Dartmouth, Nova Scotia, is Canada's largest center for ocean research, hosting over 600 staff from several federal departments.

Bedload

Bedload is the part of a stream's sediment load that moves by sliding, rolling, or skipping on or very near the streambed, generally much less than the suspended load.

Beetaloo Sub-basin

The Beetaloo Sub-basin is a Mesoproterozoic sedimentary sub-basin in the Northern Territory of Australia, its most advanced shale gas play, covering about 28,000 square kilometers.

Before the Flood (film)

Before the Flood is a 2016 American climate change documentary directed by Fisher Stevens and starring Leonardo DiCaprio, released by National Geographic in 171 countries.

Beidellite

Beidellite (IMA symbol Bei) is a dioctahedral smectite clay mineral named in 1925 for Beidell, Colorado, with layer charge arising mainly in the tetrahedral sheet.

Bellevue Gold

Bellevue Gold is an Australian gold mining company operating a high-grade underground mine near Leinster in Western Australia, which poured first gold in October 2023.

Belt Supergroup

The Belt Supergroup is a 15 to 20 km thick succession of Mesoproterozoic sedimentary rocks exposed in Montana, Idaho, Washington, and adjacent Canada, forming most of Glacier National Park.