Glossary of Terms and Acronyms - G - I

GAS MONITOR

Gas monitors measure trace gases.

GERDIEN CONDUCTIVITY PROBE

Device designed to determine the electrical conductivity of the atmosphere. By using a capacitor exposed to a sample of air and measuring the time it takes for discharge, the electrical conductivity of the sample is determined.

GLOBAL

Relating to the entire earth or other planet

GMS

Geostationary Meteorological Satellite Program was Japan's contribution to the International Global Atmospheric Research Program and World Weather Watch and consisted of a series of geostationary spin-stabilized satellites stationed near 140 degrees East longitude.

GMS-4

Geostationary Meteorological Satellite (GMS)-4 is a Japanese satellite (similar to GOES-7) in geostationary orbit over the equator at approximately 140E. The satellite is equipped with the Visible and Infrared Spin Scan Radiometer (VISSR) imaging sensor, which uses the spin motion of the satellite to scan the earth in the East-West direction. GMS begins a North-South scan every hour on the half hour, with four additional scans daily for wind estimation. At the satellite subpoint, the visible (0.5-0.75 um) channel has a resolution of 1.25 km (although, the GHCC archives a reduced resolution 5 km visible image) and the infrared (10.5-12.5 um) channel has a resolution of 5 km.

GOES

Geostationary Operational Environmental Satellite system: A series of earth-synchronous United States satellites spaced in longitude over the equator in the western hemisphere to provide near-continuous observations of the earth and its atmosphere. GOES satellites 1-7 were spin stabilized, but are no longer in service. GOES 8-10 are 3 axis stabilized.

GOES-10

Geostationary Operational Environmental Satellite 10: the tenth in a series of US satellites in earth synchronous orbit. It is presently in 'on orbit storage' at approximately 90W ready to replace either GOES-8 or GOES-9 should either fail on orbit.

GOES-11

Geostationary Operational Environmental Satellite 11: the 11th in a series of U.S. satellites in geostationary orbit over the equator in earth synchronous orbit. GOES-11 is presently in an active standby mode, and is not functioning. It was brought into operational status for the TCSP mission, providing hurricane and tropical storm coverage for all of Central America.

GOES-11 IMAGER

The GOES-11 imager is a five channel (one visible, four infrared) imaging radiometer designed to sense radiant and solar reflected energy from sampled areas of the earth. It provides near continuous observation (three axis stabilized staring imager) in the visible and infrared portions of the electromagnetic spectrum. At the satellite subpoint, the visible channel (0.55-0.75 um) has a spatial resolution of 1.0 km, the shortwave infrared channel (3.8-4.0 um) and two longwave infrared (10.2-12.5 um) channels have a resolution of 4 km, while the water vapor channel (6.7-7.0 um) has an 8.0 km resolution.

GOES-12

Geostationary Operational Environmental Satellite 12: the 12th in a series of U.S. satellites in geostationary orbit over the equator in earth synchronous orbit. Known as GOES-M it was launched on 7/23/2001 and its orbit as GOES-12 became effective on 4/1/2003.

GOES-12 IMAGER

The GOES-12 imager is a five channel (one visible, four infrared) imaging radiometer designed to sense radiant and solar reflected energy from sampled areas of the earth. It provides near continuous observation (three axis stabilized staring imager) in the visible and infrared portions of the electromagnetic spectrum. At the satellite subpoint, the visible channel (0.55-0.75 um) has a spatial resolution of 1.0 km, the shortwave infrared channel (3.76-4.03 um) and two longwave infrared (10.23-11.24 um) channels have a resolution of 4 km, while the water vapor channel (5.77-7.33 um) has an 4.0 km resolution. The CO2 channel (12.96-13.72 um wavelength) has a spatial resolution of 4 km. Comparing with GOES 11, GOES-12's Channel 3 has a different resolution, channel 5 has been lost and channel 6 has been added.

GOES-8

Geostationary Operational Environmental Satellite 8: the eighth in a series of U.S. satellites in geostationary orbit over the equator in earth synchronous orbit. GOES-8 (also called GOES East) is presently stationed at 75W observing the Atlantic Ocean (providing hurricane and tropical storm coverage) and most of North and South America.

GOES-8 IMAGER

The GOES-8 imager is a five channel (one visible, four infrared) imaging radiometer designed to sense radiant and solar reflected energy from sampled areas of the earth. It provides near continuous observation (three axis stabilized staring imager) in the visible and infrared portions of the electromagnetic spectrum. At the satellite subpoint, the visible channel (0.55-0.75 um) has a spatial resolution of 1.0 km, the shortwave infrared channel (3.8-4.0 um) and two longwave infrared (10.2-12.5 um) channels have a resolution of 4 km, while the water vapor channel (6.7-7.0 um) has an 8.0 km resolution.

GOES-9

Geostationary Operational Environmental Satellite 9: the ninth in a series of US satellites in geostationary orbit over the equator in earth synchronous orbit. GOES-9 (also called GOES West) is presently stationed at 105W observing the Eastern Pacific Ocean and the United States. The GOES-9 imager is a five channel (one visible, four infrared) imaging radiometer designed to sense radiant and solar reflected energy from sampled areas of the earth. It provides near continuous observation (three axis stabilized staring imager) in the visible and infrared portions of the electromagnetic spectrum. At the satellite subpoint, the visible channel (0.55-0.75 um) has a spatial resolution of 1.0 km, the shortwave infrared channel (3.8-4.0 um) and two longwave infrared (10.2-12.5 um) channels have a resolution of 4 km, while the water vapor channel (6.7-7.0 um) has an 8.0 km resolution.

GOES-9 IMAGER

The GOES-9 imager is a five channel (one visible, four infrared) imaging radiometer designed to sense radiant and solar reflected energy from sampled areas of the earth. It provides near continuous observation (three axis stabilized staring imager) in the visible and infrared portions of the electromagnetic spectrum. At the satellite subpoint, the visible channel (0.55-0.75 um) has a spatial resolution of 1.0 km, the shortwave infrared channel (3.8-4.0 um) and two longwave infrared (10.2-12.5 um) channels have a resolution of 4 km, while the water vapor channel (6.7-7.0 um) has an 8.0 km resolution.

GPCP

The purpose of the Global Precipitation Climatology Project (GPCP) is to derive gridded data sets of monthly precipitation totals covering the entire globe based on all available observation technologies and data. Data are gathered at the Global Precipitation Climatology Center (GPCC) which operates under objectives defined by the World Climate Research Program (WCRP). The GPCP contributes data sets to the Global Energy and Water Cycle Experiment (GEWEX) and is expected to be a component of the Global Climate Observing System (GCOS).

GPS

Global Positioning System. A constellation of satellites in low earth orbit which provide information to receivers which then internally calculate their (the receivers) location in 3-dimentional space. Accuracy is within 10 meters.

GPS CLOCK

The Global Positioning System (GPS) clock.

GROUND STATION

Land surface observation site

GROUND-BASED OBSERVATION

Measurement of phenomena made with instrumentation which is located at a specific point on the surface of the earth.

HAMSR

The High Altitude monolithic microwave integrated Circuit (MMIC) Sounding Radiometer (HAMSR) is a microwave atmospheric sounder recently developed by JPL under the NASA Instrument Incubator Probram. Operating with 25 spectral channels in the 50-190 HGz region, it provides measurements that can be used to infer the 3-D distribution of temperature, water vapor, and liquid water in the atmosphere, even in the presence of clouds. HAMSR was mounted in a wing pod of a research aircraft.

HDF

Hierarchial Data Format is a multi-object format that is designed to facilitate the sharing of data among people, project, and machines on a network. Public domain software from HDF at NCSA.

HEAT FLUX

The amount of heat entering a specified cross-sectional area of a surface per unit time.

HUMAN OBSERVER

A human being who observes, measures, and records scientific data in the absence of more precise or automated means.

HUMIDITY

A measure of the water-vapor content of air.

HURRICANE MISSION REPORT

A hurricane mission report is a short in-field science report that has high level information about a campaign's daily mission. It includes the mission date, sortie number(s), a mission description, mission objective, mission notes, and a summary of ground /other assets. It is written by the mission scientist in charge of that day's mission.

HURRICANES

Severe tropical cyclones having winds in excess of 64 knots (74 mi/hr).

HVPS

The High Volume Precipitation Spectrometer measures particle size and operates by taking a two-dimensional shadow digital picture of the particles that pass through a 4.5 x 20.3 cm laser light plane that is normal to the direction of aircraft flight. The sheet of light is imaged onto a linear array of 256 photo-elements. The HVPS has 200 mm pixel resolution when measured across the array.

HYDROMETEORS

Particles in the atmosphere composed of water, e.g. ice, raindrops, snow, etc.

HYGROMETER

An instrument designed to measure absolute and relative humidity of the atmosphere.

INFRARED IMAGERY

Imagery created in the portion of the electromagnetic spectrum. The Infrared (IR) region of the spectrum has wavelengths between approximately .75 microns to 100 microns, but imagery created using meteorlogical satellites typically is created using the 10-12.5 micron portion of the spectrum. This 'window' is relatively transparent to infrared radiation.

INFRARED PYROMETER

A device which allows contact less temperature measure by the use of infrared radiation.

INFRARED RADIANCE

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

INS

Inertial Navigation System. Using a series of orthogonally mounted accelerometers which detect changes from straight line motion, this device provides a self contained and independent method by which it can determine positional changes from a starting point. INS units are extensively used in spacecraft, ships and aircraft.

INTEGRATED WATER VAPOR

A measure of the columnar water vapor in the earth's atmosphere in grams per square centimeter.

IR

The Infrared (IR) region of the spectrum has wavelengths between approximately .75 microns to 100 microns. Infared Radiometer: An instrument for measuring longwave radiation (between visible and microwave spectrum) lying in the wavelength interval from about 0.75 microns to approximately 100 microns.

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