| 中尺度影像光譜儀 | Moderate Resolution Imaging Spectroradiometer, MODIS |
| 錨繫浮標 | Moored Buoy |
| 動船法 | Moving Boat Method |
| 中子散射法 | Neutron-scattering Method |
| 感雨器 | Ombroscope |
| 光學流速儀 | Optical Current Meter |
| 光學式雨滴譜儀 | Optical Distrometer |
| 光學式雨量計 | Optical Rain Gauge, ORG |
| 巴歇爾水槽 | Parshall Flume |
| 顆粒影像測速法 | Particle Image Velocimetry, PIV |
| 洪峰流量 | Peak Flow |
| 海上觀測樁 | Pile Station |
| 皮托管 | Pitot Tube |
| 點取樣器 | Point-integrating Suspended-sediment |
| 點降水量 | Point precipitation |
| 降雨強度 | Precipitation Intensity |
| 壓力探測器 | Pressure Detector |
| 水壓式水位計 | Pressure Type Stage Recorder |
| 普萊斯流速儀 | Price Current Meter |
| 主水尺 | Principal Gage |