| Abbreviation | Definition |
|---|---|
| RAMAN | Regional Atmospheric Measurement and Analysis Network |
| RAMM | Regional and Mesoscale Meteorology |
| RAMS | Regional Atmospheric Modeling System |
| RAN | Royal Australian Navy |
| RANN | Research Applied to National Needs |
| RAO | Response Amplitude Operator |
| RAOB | Rawindsonde Observation |
| RAP | Regional Analysis and Prediction |
| RAS | River Analysis System |
| RAS | Royal Astronomical Society |
| RATCHET | Regional Atmospheric Transport Code for Hanford Emission Tracking |
| RAWIN | Radar Wind Sounding |
| RAWINSONES | radiosonde and RAWIN |
| RAWINSONES | Radiosonde and RAWIN (Radar Wind Sounding) |
| RBFLW | Reflected Breakpoint Forced Long Wave |
| RBI | Really Big Ice |
| RBLW | Reflected Bound Long Wave |
| RBO | Rivers, Bays, and Oceans |
| Rc | Radius of Curvature of river or stream |
| RCC | Red Claw Crab |