| Abbreviation | Definition |
|---|---|
| ABL | Atmospheric Boundary Layer |
| ABLE | Arctic Boundary Layer Expedition |
| ABLE | Atmospheric Boundary Layer Experiment |
| ABMN | Aquatic Biodiversity Monitoring Network |
| ABOM | Australian Bureau of Meteorology |
| ABS | Air Breathing System |
| ABW | Antarctic Bottom Water |
| ACAP | Atlantic Coastal Action Program |
| ACARS | ARINC Communications Addressing and Reporting System |
| ACATS | Airborne Chromatograph For Atmospheric Trace Species |
| ACC | Alaska Coastal Current |
| ACC | Antarctic Circumpolar Current |
| ACC | Anthropogenic Climate Change |
| ACCAD | Advisory Committee on Climate Applications and Data |
| ACCE | Atlantic Circulation and Climate Experiment |
| ACCP | Atlantic Climate Change Program |
| ACCW | Antarctic Circumpolar Coastal Wave |
| ACE | Advanced Composition Explorer |
| ACE | Aerosol Characterization Experiment |
| ACE | Antarctic Current Experiment |