| Abbreviation | Definition |
|---|---|
| AMO | the Atlantic Multidecadal Oscillation |
| AMOS | Automated Meteorological Observing System |
| AMS | Accelerator Mass Spectrometer |
| AMS | accelerator mass spectrometer/spectrometry |
| AMSET | Aquatic Management Systems and Environmental Technology |
| AMSI | Arctic Maritime Safety Information |
| AMSU | Advanced Microwave Sounding Unit |
| AMTEX | Air-Mass Transportation Experiment |
| AN/UMK-3 | Tactical Environmental Support System / Shipboard Meteorological and Oceanographic Observing System |
| ANCS-II | Automated Nautical Charting System |
| ANGUS | Acoustically Navigated Geological Underwater Survey |
| ANICA | Atmospheric Nutrient Input to Coastal Areas |
| ANS | Aquatic Nuisance Species |
| AO | Arctic Oscillation |
| AO | Atlantic Ocean |
| AOC | Aircraft Operations Center |
| AOD | Aerosol Optical Depth |
| AOFLA | Artlantic Offshore Fish and Lobster Association |
| AOIPS | Atmospheric and Oceanographic Information Processing System |
| AOMIP | Arctic Ocean Model Intercomparison Project |