Glossary of Terms and Acronyms - T - V

TC4

The NASA TC4 (Tropical Composition, Cloud and Climate Coupling) mission investigated the atmospheric structure, properties and processes in the tropical Eastern Pacific. The primary area of interest was the atmosphere layer between approximately 46,000 ft and 59,000 ft (14-18 km). This is where the lower part of the atmosphere (the troposphere) meets the upper part (the stratosphere). The TC4 mission was sponsored by the NASA Headquarters Atmospheric Composition Focus Area, including the Upper Atmospheric Research Program, the Radiation Science Program, and the Tropospheric Chemistry Program. The field experiment phase was completed during July and August 2007 based out of San Jose, Costa Rica.

TCSP

The Tropical Cloud Systems and Processes (TCSP) mission is a field research investigation sponsored by the Science Mission Directorate of the National Aeronautics and Space Administration (NASA). TCSP is focused on the study of the dynamics and thermodynamics of precipitating cloud systems, including tropical cyclones using NASA-funded aircraft and surface remote sensing instrumentation.

TEFLUN-A

The TExas and FLorida UNderflights (TEFLUN) Experiment was a mission to obtain validation measurements for the Tropical Rain Measuring Mission (TRMM). TRMM is a NASA and National Space Development Agency of Japan (NASDA) coordinated mission that launched the TRMM satellite on 28 November 1997 with a unique complement of sensors to remotely observe rainfall throughout the global tropics. TEFLUN was the first in a series of experiments using a combination of airborne and surface-based measurements to complement the satellite data. Among these, were important measurements aboard the NASA high-altitude aircraft, similar to those on the TRMM satellite. They are used for direct intercomparisons with TRMM overflights where possible, but more frequently to simulate TRMM data by flying over precipitation systems within the experimental domain. These, along with surface-based measurements and computer models, will make unique contributions to our understanding of the tropical precipitation cycle.

TEFLUN-B

The Texas Florida Underflight Experiment (TEFLUN) is a series of field research investigations sponsored by the Earth Science Enterprise of the National Aeronautics and Space Administration (NASA). TEFLUN-B took place in conjunction with CAMEX-3, and collected data from 8 August through 23 September, 1998, to study tropical convective precipitation using NASA-funded aircraft and surface remote sensing instrumentation.

TEMPERATURE

Average kinetic energy of a substance measured in degrees.

TEMPERATURE PROBE

A device used to directly measure the temperature in a substance, be it soil, water or air. Temperature probes are used on aircraft to measure outside air temperature; often in conjunction with other sensors as in Bowen ratio apparatus; or used to determine water temperature.

TEMPERATURE PROFILES

A record of temperature versus height at a specific geographic location.

TERRA

Terra formerly known as EOS AM-1, launched 18 December 1999, is the flagship of the NASA Earth Science Enterprise (ESE). It observes and measures the state of the Earth system, while also monitoring global environmental changes over time. TERRA carries 5 state-of-the-art instruments uniquely designed to provide data with unprecendented precision, quality, and scope. These data are processed into continuous long-term measures of the state of the atmosphere, land, and oceans. The 5 instruments include the 1) Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), obtaining high-resolution images at 14 wavelengths (VIS and IR), 2) Clouds and the Earth's Radiant Energy System (CERES), measuring the radiation budget and providing cloud property estimates, 3) Multi-angle Imaging Spectro-Radiometer (MISR), containing 9 cameras imaging at 4 wavelengths (VIS and IR), 4) Moderate-resolution Imaging Spectroradiometer (MODIS), observing in 36 spectral bands, and 5) Measurements of Pollution in the Troposphere (MOPITT), observing in 3 spectral bands using gas correlation spectroscopy.

THERMISTOR

A resistive circuit component, having a high negative temperature coefficient of resistance, so that its resistance decreases as the temperature increases. It is a stable, compact, rugged two-terminal ceramic like semiconductor head, rod, or disk. Derived from thermal resistance.

THERMOMETER

An instrument for measuring temperature.

TMI

The TRMM Microwave Imager (TMI) is a 5-channel, dual-polarized, passive microwave radiometer. Microwave radiation is emitted by the Earth's surface and by water droplets within clouds. The TMI is used to measure several important meterological parameter over sea surfaces. The TMI, a successor to the SSM/I measures radiation at frequencies of 10.7, 19.4, 21.3 85.5 GHz. It orbits at an altitude of 218 miles, much lower than the SSM/I, thus providing better resolution.

TOGA COARE

Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment - a large scale field observation campaign (11/92 to 2/93) conducted over the western Pacific warm pool.

TOGA RADAR

Doppler scanning radar operating in the C-band with horizontal and vertical polarization. Used for detection and detailing wind direction/velocities in the x, y and z direction as well as precipitation reflectivities.

TOTAL PRESSURE

Measurement made in a pitot-static system which is the sum of ram air pressure plus the ambient pressure of the air entering the pitot tube.

TOTAL SKY IMAGER

Total Sky Imager by the Yankee Environmental Systems is a full color sky camera and software package for sky imaging, recording up to 6 images per minute. A nephelometer and an aerodynamic particle sizer are also incorporated for measuring the aerosol particles and light scattering.

TOTAL TEMPERATURE

Measurement made using a temperature probe (e.g. thermistor) which is the sum of the ambient air temperature plus the heat of friction caused by the high speed air passing over the probe.

TOTAL WATER

The total atmospheric water vapor contained in a vertical column of unit cross-sectional area extending between any two specified levels, commonly expressed in terms of the height to which that water substance would stand if completely condensed and collected in a vessel of the same unit cross section.

TOVS

TIROS Operational Vertical Sounder. The TOVS instrumentation on-board the NOAA stellites consists of 1) the second version of the High-resolution Infrared Radiation Sounder (HIRS-2), 2) the Microwave Sounding Unit (MSU) and 3) the Stratospheric Sounding Unit (SSU).

TRACE GASES

Concentration of gases in the atmosphere that do not occur in large quantities but are significant to life on Earth or are important constituents of the chemical cycles in the atmosphere.

TRACE GASES/TRACE SPECIES

Concentration of gases/species in the atmosphere that do not occur in large quantities but are significant to life on Earth or are important constituents of the chemical cycles in the atmosphere.

TRMM

The Tropical Rainfall Measuring Mission (TRMM) is a joint mission between NASA and the National Space Development Agency (NASDA) of Japan designed to monitor and study tropical rainfall and the associated release of energy that helps to power the global atmospheric circulation shaping both weather and climate around the globe. The TRMM Observatory carries five instruments: the first spaceborne Precipitation Radar (PR), the TRMM Microwave Imager (TMI), a Visible and Infrared Scanner (VIRS), a Cloud and Earth Radiant Energy System (CERES), and a Lightning Imaging Sensor (LIS).

TRMM

The Tropical Rainfall Measuring Mission (TRMM) is a joint mission between NASA and the National Space Development Agency (NASDA) of Japan designed to monitor and study tropical rainfall and the associated release of energy that helps to power the global atmospheric circulation shaping both weather and climate around the globe. The TRMM Observatory carries five instruments: the first spaceborne Precipitation Radar (PR), the TRMM Microwave Imager (TMI), a Visible and Infrared Scanner (VIRS), a Cloud and Earth Radiant Energy System (CERES), and a Lightning Imaging Sensor (LIS).

TRMM-LBA

The Tropical Rainfall Measuring Mission (TRMM) is a joint mission between NASA and the National Space Development Agency (NASDA) of Japan designed to monitor and study tropical rainfall and the associated release of energy that helps to power the global atmospheric circulation shaping both weather and climate around the globe. The TRMM Observatory carries five instruments: the first spaceborne Precipitation Radar (PR), the TRMM Microwave Imager (TMI), a Visible and Infrared Scanner (VIRS), a Cloud and Earth Radiant Energy System (CERES), and a Lightning Imaging Sensor (LIS).

TROPOSPHERE TEMPERATURE

Atmospheric temperature extending from the earth's surface to the tropopause

TURBULENCE

The irregular and instantaneous motions of a liquid or gas which is made up of a number of small eddies that travel in the general flow direction.

ULTRAVIOLET RADIATION

Electromagnetic radiation of shorter wavelength than visible radiation but longer than x-rays. Wavelengths range from 5 - 400mm.

UNESCO

UNESCO, the United Nations Educational, Scientific, and Cultural Organization, is a Specialized Agency of the United Nations. The main objective of UNESCO is to contribute to peace and security in the world by promoting collaboration among nations through education, science, culture and communication in order to further universal respect for justice, for the rule of law and for the human rights and fundamental freedoms which are affirmed for the peoples of the world, without distinction of race, sex, language or religion, by the Charter of the United Nations.

UPPER LEVEL WINDS

Atmospheric winds above the surface measured by either radiosonde (weather balloon) or aircraft, or derived from satellite imagery.

UPPER TROPOSPHERE TEMPERATURE

Atmospheric temperature measured in degrees Kelvin extending from 500 to 100 hPa.

VERTICAL WIND MOTION

The component of the wind velocity vector rising perpendicular to the plane of the horizon.

VIDEO CAMERA

Device used to capture moving images that can then be replayed on a monitor.

VISIBLE IMAGERY

The product of an imager observing in the visible portion of the spectrum. These are the most familiar of the meteorological satellite products, and are often displayed during the evening news and called erroneously 'satellite pictures'.

VISIBLE RADIANCE

Upwelling radiation in the visible portion of the spectrum which is observed by the spacecraft instrumentation.

VISSR

Visible Infrared Spin Scan Radiometer (VISSR) is a two channel instrument observing in the infrared and visible portion of the electromagnetic spectrum that provides day/night observations of cloud cover and earth/cloud radiance temperatures over a partial or full earth disk for use in operational weather analysis and forecasting.

NASA Information Contact: Michael Goodman, Global Hydrology and Climate Center GHRC Web Curator: GHRC Web Team Last update: Friday, 13-Sep-02 09:37:01 CDT If you have trouble viewing or navigating this page, please contact GHRC User Services. U.S. Government Compliance report.