| Abbreviation | Definition |
|---|---|
| ARCICE | Arctic Ice and Environmental Variability |
| ARCS | Assessment And Remediation Of Contaminated Sediments |
| ARCSS | Arctic System Science |
| AREP | Atmospheric Research and Environment Program |
| ARI | Accelerated Research Initiative |
| ARINC | Aeronautical Radio, Incorporated |
| ARL | Air Resources Laboratory |
| ARL | Arctic Research Laboratory |
| ARM | Atmospheric Radiation Measurement |
| ARMA | Autoregressive Moving Average |
| ARMAP | Arctic Research Mapping Application |
| ARPS | Advanced Regional Prediction System |
| ART | Airborne Radiation Thermometer |
| ARTCC | Air Route Traffic Control Center |
| ASAN | Australian Salinity Action Network |
| ASAR | Advanced Synthetic Aperture Radar |
| ASC | Acoustic Seabed Classification |
| ASC | Administrative Support Center |
| ASCE | American Society of Civil Engineers |
| ASCOT | Atmospheric Studies in Complex Terrain |