| Abbreviation | Definition |
|---|---|
| IMS | Inland Mapping System |
| IMS | Ionospheric Measuring System |
| IMY | Institutionalized Meterological Yanostrasm |
| INSAM | International Society for Agricultural Meteorology |
| INTEL | Idaho National Engineering Laboratory |
| IOCO | Indian Ocean Climatology & Oceanography |
| IOCQ | Important Other Climate Questionnaire |
| IOCZ | Inter-Ocean Convergence Zone |
| IODC | Indian Ocean Date Coverage |
| IOLC | Indian Ocean Low Clouds |
| IP | Invisible Particles |
| IPO | Integrated Program Office |
| IQ | Information Quality |
| IR | Interaction Region |
| IR | Interregional Research |
| IRI | International Reference Ionosphere |
| ISBN | International Space Bus Network |
| ISCCP | International Satellite Cloud Climatology Program |
| ISR | Ice Sheet Reconstruction |
| ITA | International Tornado Association |