Ta-Tm

 

2050 Project

A joint project among the World Resources Institute, the Brookings Institution, and the Santa Fe Institute to explore the question of how a sustainable existence on this planet can be achieved by the middle of the next century. More information can be found at the 2050 Project Web site.

 

TAGB

Abbreviation for total aboveground biomass.

 

taiga

A biome consisting of swampy coniferous forests in high northern latitudes.

 

TAMU

Abbreviation for Texas A&M University. There is a graduate school of oceanography at this institution, more about which can be obtained at the TAMU Oceanography Web site.

 

TAO

Acronym for Tropical Atmosphere Ocean array, a TOGA experiment. See the TAO data site and also Hayes et al. (1990) and McPhaden (1995).

 

taphonomy

The branch of paleontology that deals with the processes by which animal and plant remains become preserved as fossils, i.e. the changes undergone by an organism from its death until its discovery as a fossil. See Briggs and Crowther (1990), Ch. 3.

 

TARFOX

Acronym for Tropospheric Aerosol Radiative Forcing Observational Experiment, a field project of IGAC to measure the direct effects of tropospheric aerosols on regional radiation budgets of the cloud-free atmosphere, while simultaneously measuring the chemical, physical, and optical properties of the responsible aerosols. Other goals are to perform a radiative column closure study in one of the most polluted regions of the globe, i.e. the U.S. eastern seaboard, and the extend these measurements and analyses to other regions of the globe using validated satellite measurements. See the TARFOX Web site.

 

TAS

Abbreviation for Tropical Atlantic Study.

 

Tatarskyi Strait

See Okhotsk Sea.

 

taxon

A taxonomic group of any rank, e.g. species, family, class, etc.; an organism contained in such a group. The plural is taxa.

 

taxonomy

The theory and practice of classifying organisms. Its components include classification, nomenclature, circumspection or description, and identification aids. In the strict biological sense it refers to all information science aspects of handling the different sets of organisms. Taxonomy should be distinguished from the broader topic of biosystematics. See Heywood (1995).

 

Taylor column

If relative motion is created in a rotating container by heating or by stirring and if an obstacle is placed on the bottom of the tank so that the moving fluid must flow around it, then the streamlines of the flow will form a column, going around the obstacle as if it extended to the top of the water. This is called a Taylor column. The same sort of phenomena can occur in real world analogues of this experimental example. This is a consequence of what is known as the Taylor-Proudman theorem. See Dutton (1986).

 

Taylor-Proudman theorem

A two-dimensional fluid flow theorem that states that geostrophic motion of a homogeneous fluid will be the same in all planes perpendicular to the axis of rotation. This has also been known as the Proudman-Taylor, Proudman or Taylor theorem. See Hide (1978).

 

TBM

Abbreviation for Terrestrial Biogeochemical Model.

 

TDRSS

Abbreviation for Tracking and Data Relay Satellite System, a constellation of NASA satellites and ground stations that track and relay data to and from low-altitude, Earth-orbiting satellites.

 

teleconnections

Global scale modes of variability.

 

temperate

Descriptive of a climate in which the temperatures are moderate or mild, or of any climate in middle latitudes.

 

temperature inversion

In meteorology, a region of negative lapse rate.

 

temperature lapse rate

The rate of decrease of temperature with height.

 

temporale

A cyclonic tropical weather system that affects the Pacific side of Central America and originates in the Pacific Intertropical Convergence Zone. These systems are characterized by very heavy rainfalls over several days. Unlike hurricanes, similarly wet systems, their winds are usually weak and they possess a cold mid-tropospheric core. They are typically move slowly, last several days, and cause damaging floods and landslides in the mountainous regions of Central America.

 

TERRA

Acronym for Terrestrial Ecosystems Regional Research and Analysis Laboratory, whose mission is to incorporate realistic consideration of land and natural resource management understanding into terrestrial ecosystem components of earth system modeling. See the TERRA Web site.

 

TerrainBase

An ongoing project to develop a research quality collection of digital terrain models. See the TerrainBase Web site.

 

TERRA Nova

A fast publication research, review and news journal covering the full range of the Earth sciences. It is the official journal of the European Union of Geosciences, and selected articles can be found online at the TERRA Nova Web site.

 

Tertiary

The first of two periods of the Cenozoic era, lasting from 66.4 to 1.6 Ma. It precedes the Quaternary period and follows the Cretaceous period of the Mesozoic era, and is comprised of the Paleocene, Eocene, Oligocene, Miocene, and Pliocene epochs. Originally designated an era, it had the five periods rather than epochs listed above or, alternatively, the Paleogene and Neogene periods where the boundary coincided with that of the Oligocene and Miocene.

 

TES

Acronym for Tropospheric Emission Spectrometer.

 

Tethys Sea

A paleogeographic term for a sea that separated the two Mesozoic supercontinents of Laurasia and Gondwana.

 

thermal diffusivity

A number that characterizes the rate of molecular diffusion of heat in a liquid. In the temperature range from 0 to 30 C, this varies from 0.1809 to 0.284 cm /s for air and from 0.0013 to 0.0015 cm /s for water.

 

thermal equator

An imaginary line connecting those points around the globe with the highest mean temperature for the given period. As such, the position of the thermal equator varies with the season. Due to the thermal inertia of the ocean, the position of this moves north and south with the Sun but is always between the Sun and the geographic equator. The mean position is north of the geographic equator due mainly to the majority of land masses being in the northern hemisphere.

 

thermal wind equations

These allow the calculation of the vertical variation of velocity from the density field. The name thermal is an artifact from the original meteorological use where the temperature field was used as a proxy for the density field. In oceanography, the fact that salinity can also significantly contribute to variations in the density field leads to the use of density rather than temperature. The thermal wind equations are derived from the horizontal equations of motion and the hydrostatic equation, beginning with the equations of motion reduced to the geostrophic equations, i.e.

where is the Coriolis parameter, u and v the horizontal velocity components, p the pressure, and the density. The vertical derivative of each equation is taken, the order of differentiation switched for the pressure, and the hydrostatic equation ( ) substituted to obtain

These equations only give the variation of the velocity with depth. Further information must be supplied to obtain absolute velocities.

 

thermocline

Generally a layer of water with a more intensive vertical gradient in temperature than in the layers either above or below it. The depth and thickness of these layers vary with season, latitude and longitude, and local environmental conditions. In the ocean there is a permanent thermocline residing from 100-700 meters below the surface, a seasonal thermocline that varies with the seasons (developing in spring, becoming stronger in summer, and disappearing in fall and winter), and a diurnal thermocline that forms very near the surface during the day and disappears at night. A review of the governing dynamics of the permanent thermocline can be found in Pedlosky (1987).

 

thermogram

See thermograph.

 

thermograph

A recording thermometer which measures a continuous trace of temperature called a thermogram. The classical version of this featured a bi-metallic strip attached to a lever holding a pen. As the strip expanded and contracted in response to temperature changes, the pen moved across a piece of paper on a drum rotating via some clockwork mechanim. Such things are done using solid state devices sending binary data to other solid state devices in these modern times.

 

thermohaline

In oceanography, descriptive of a combination of temperature and salinity effects.

 

thermohaline circulation

That part of the ocean circulation driven by temporal and spatial differences in both the salinity and temperature of the waters that comprise the world ocean. A simplified schematic model of this circulation is the conveyor belt model.

 

thermohaline convection

See double diffusive convection.

 

thermophoresis

Migration of aerosol down a temperature gradient. See Jaenicke (1993a).

 

thermosolutal convection

See double diffusive convection.

 

thermostad

A layer where the vertical change of temperature is very small and displays a local minimum.

 

thermosteric anomaly

In the determination of the specific volume of sea water, this refers to a subset of that group of factors known as the specific volume anomaly that account for most of the effects of salinities and temperatures that differ from the standard calculation levels of 35 ppt and 0 deg. C, respectively. These three terms account for the individual effects of salinity and temperature perturbations as well as their combined effect.

 

THIR

Acronym for Temperature Humidity Infrared Radiometer, an instrument flown on Nimbus 7.

 

Thomson, Charles Wyville

More later.

 

Thornthwaite scheme

A bioclimatic classification scheme that treats plants as physical mechanisms by which moisture is returned to the air. The variables APE and AAE are used in this scheme to distinguish between situations when the amount of moisture available to plants is limiting or nonlimiting. The APE in this case is calculated via a formula given in Thornthwaite (1948). See Prentice (1990).

 

tidal bore

To be completed.

 

tidal wave

An egregious misnomer for a type of wave that has nothing to do with tides or tide-producing forces. See the more apt term seismic sea wave for a description.

 

tide

The periodic rising and falling of the water that results from the gravitational attraction of the moon and sun acting on the rotating earth. There are related phenomena that occur in the solid earth and the atmosphere called, strangely enough, earth tides and atmospheric tides. The forces that significantly effect the tides of the oceans are the gravitational forces of the sun and moon, the centrifugal force due to the movement of the earth in its orbit, the Coriolis force, and the frictional force due to the movement of the water with respect to its boundaries. See Wiegel (1964).

 

tilt

See obliquity.

 

time series

Any series of observations of a physical variable that is sampled at changing time intervals. A regular sampling interval is usually presumed although not required.

 

time step

The basic unit of temporal resolution in a numerical model created by discretizing a continuum differential equation to create an analogous discrete algebraic equation. The model time advances by discrete steps as opposed to the (at least perceived) continuum nature of time in the real world.

 

TIROS

Acronym for the Television Infrared Observation Satellite.

 

Tithonian

The last of three ages in the Late Jurassic epoch, lasting from 152 to 144 Ma. It is preceded by the Kimmeridgian age and followed by the Berriasian age of the Early Cretaceous epoch.

 

TIWE

Abbreviation for Tropical Instability Wave Experiment.