| ABBA | Automated Biomass Burning Algorithm | - | Scuba Diving |
| ABI | Advanced Baseline Imager | - | Scuba Diving |
| ABS | Advanced Baseline Sounder | - | Scuba Diving |
| AC | Alternating Current | - | Scuba Diving |
| ACRIM | Active Cavity Radiometer Irradiance Monitor (EOS) | - | Scuba Diving |
| ADEOS | ADvanced Earth Observing Satellite (Japan) | - | Scuba Diving |
| AERI | Atmospheric Emitted Radiance Interferometer | - | Scuba Diving |
| AIRS | Atmospheric InfraRed Sounder (EOS) | - | Scuba Diving |
| AMRIR | Advanced Medium Resolution Infrared Radiometer | - | Scuba Diving |
| AMS | American Meteorological Society | - | Scuba Diving |
| AMSU | Advanced Microwave Sounder Unit (EOS) | - | Scuba Diving |
| AO&SS | Atmospheric | - | Scuba Diving |
| AOS | (Department Of) Atmospheric And Oceanic Sciences | - | Scuba Diving |
| AOT | Aerosol Optical Thickness | - | Scuba Diving |
| APP | AVHRR Polar Pathfinder | - | Scuba Diving |
| ASPT | Advanced Satellite Products Team (NOAA/ORA) | - | Scuba Diving |
| ASTER | Advanced Spaceborne Thermal Emission And Reflection Radiometer (EOS) | - | Scuba Diving |
| ATOVS | Advanced TIROS Operational Vertical Sounder | - | Scuba Diving |
| AU | Astronomical Unit | - | Scuba Diving |
| AURA | Association Of Universities For Research In Astronomy | - | Scuba Diving |
| AVHRR | Advanced Very High Resolution Radiometer | - | Scuba Diving |
| AVIRIS | Airborne Visible InfraRed Imaging Spectrometer (JPL) | - | Scuba Diving |
