ACT Atacama Cosmology Telescope

AGN active galactic nucleus

ALMA Atacama Large Millimeter Array

AMSR-E Advanced Microwave Scanning Radiometer-Earth

AMSU Advanced Microwave Sounding Unit

ARM Atmospheric Radiation Monitoring

ARSR Air Route Surveillance Radars

ATA The Allen Telescope Array

ATMS Advanced Technology Microwave Sounder

AUI Associated Universities, Inc.

AVHRR Advanced Very High Resolution Radiometer

AWS Advanced Wireless Services

BOINC Berkeley Open Infrastructure for Network Computing

BRS/EBS Broadband Radio Service and Educational Broadband Service

CAPE connective available potential energy

CCAT Cornell Caltech Atacama Telescope

CFC chlorofluorocarbon

CMB cosmic microwave background

CME coronal mass ejection

CMIS Compact Microscope Imaging System

COBE Cosmic Background Explorer

CORF Committee on Radio Frequencies

CR cognitive radio

DDA direct data assimilation

DFS dynamic frequency selection

DIA Denver International Airport

DMSP Defense Meteorological Satellite Program

DOD Department of Defense

ECV essential climate variable

EDR Environmental Data Record

EESS Earth Exploration-Satellite Service

EIRP equivalent isotropically radiated power

EOS Earth Observing System

ESMR Electrical Scanning Microwave Radiometer

ESTAR Electronically-Scanned Thinned Array Radiometer

EVLA Expanded Very Large Array

FASR Frequency Agile Solar Radiotelescope

FCC Federal Communications Commission

FS Fixed Service

GBT Green Bank Telescope

GCOM-W Global Change Observation Mission-Water

GCOS Global Climate Observing System

GEO geostationary orbit (satellite); Group on Earth Observations

GEOSS Global Earth Observation System of Systems

GFSC Goddard Space Flight Center

GMI Global Precipitation Measurement-Microwave Imager

GOES Geostationary Operational Environmental Satellites

GPM Global Precipitation Measurement (mission)

GPS Global Positioning System

GR Einstein’s theory of general relativity

HCFC hydrochlorofluorocarbon

HFC hydrofluorocarbon

HOMER Hybrid Optimization Model for Electric Renewables

HSB Humidity Sounder for Brazil

IPCC Intergovernmental Panel on Climate Change

ITU International Telecommunication Union

ITU-R ITU Radiocommunication Sector

ITU-RR ITU Radio Regulations

IUCAF Scientific Committee on Frequency Allocations for Radio Astronomy and Space Science

IWP ice water path

JMR JASON Microwave Radiometer

LEO low Earth orbit

LI lifted index

LIGO Laser Interferometer Gravitational Wave Observatory

LISA Laser Interferometer Space Antenna

LMS Land Mobile Service

LMSS Land Mobile Satellite Service

LMT Large Millimeter Telescope

LWA Long Wavelength Array

MEMS microelectromechanical systems

MHS Microwave Humidity Sounder

MIRAS Microwave Imaging Radiometer using Aperture Synthesis

MIS Microwave Imager/Sounder

MLS Microwave Limb Sounder

MODIS Moderate Resolution Imaging Spectroradiometer

MSU microwave sounding unit

MWA Murchison Widefield Array

NAIC National Astronomy and Ionosphere Center

NASA National Aeronautics and Space Administration

NEMS Nimbus-E Microwave Spectrometer

NOAA National Oceanic and Atmospheric Administration

NPOESS National Polar-orbiting Operational Environmental Satellite System

NPRM notice of public rule making

NRAO National Radio Astronomy Observatory

NRC National Research Council

NRQZ National Radio Quiet Zone

NSF National Science Foundation

NTIA National Telecommunications and Information Administration

NWP numerical weather prediction

OOB out-of-band (emissions)

PATH Precipitation and All-Weather Temperature and Humidity

PECAD/CADRE Production Estimate and Crop Assessment Division’s Crop Condition Data Retrieval and Evaluation

pfd power flux density (usually measured in Wm^–2)

PSR Polarimetric Scanning Radiometer

PSU practical salinity unit

PWV precipitable water vapor

RAS Radio Astronomy Service

RF radio frequency

RFI radio frequency interference

RMS root-mean-square

RNSS Radionavigation Satellite Service

RR Radio Regulations (the international treaty governing spectrum use)

SAIR Synthetic Aperture Interferometric Radiometer

SAR synthetic aperture radar

SCLP Snow and Cold Land Processes

SDR software-defined radio

SETI Search For Extraterrestrial Intelligence

SFMR Stepped Frequency Microwave Radiometer

SIRICE Submillimeter Infrared Radiometer Ice Cloud Experiment

SKA Square Kilometer Array

SM soil moisture

SMAP Soil Moisture Active Passive

SMMR Scanning Multi-Channel Microwave Radiometer

SMOS Soil Moisture Ocean Salinity

SNR signal-to-noise ratio

spfd spectral power flux density (measured in Wm^–2 Hz^–1)

SPT South Pole Telescope

SPTF Spectrum Policy Task Force

SRS Space Research Service

SSM/I Special Sensor Microwave Imager

SSMI/S Special Sensor Microwave Imager/Sounder

SSM/T Special Sensor Microwave/Temperature

SSS sea surface salinity

SST sea surface temperature

SUBTEL Subsecretaría de Telecomunicaciones

SSWV sea surface wind vector

SWE snow water equivalent

TDM time-division multiplexing

TDRSS Tracking and Data Relay Satellite System

TIROS Television Infrared Observation Satellite

TMI TRMM Microwave Imager

TOPEX Topography Experiment

TOVS TIROS Operational Vertical Sounder

TRMM Tropical Rainfall Measuring Mission

TTI total of totals index

UAL United Airlines

UWB ultrawideband

VLA Very Large Array

VLBA Very Long Baseline Array

VLBI very long baseline interferometry

WMTS Wireless Medical Telemetry Service

WP7D ITU Working Party 7D

WRC World Radiocommunication Conference