| Abbreviation | Definition |
|---|---|
| MARD | Modernization and Associated Restructuring Demonstration |
| MARS | Meteorological Automatic Reporting System |
| MARSTO | North American Research Strategy on Tropospheric Ozone |
| MAS | Mass Airflow Sensor |
| MAT | Moist Acidic Tundra |
| MATES | Multiple Air Toxics Exposure Study |
| MATH | Maintaining And Targeting Health |
| MATT | Mean Annual Air Temperature |
| MB | Might Blow |
| MC | Meteorological Codes |
| MCC | Midwest Climate Center |
| MCDW | Monthly Climate Data for the World |
| MCH | Meteorological Climatological and Hydrological |
| MCIP | Meteorology Chemistry Interface Processor |
| MCSST | Multichannel Sea Surface Temperature |
| MCWG | Metrology and Calibration Working Group |
| MDD | Maximum Density Droplet |
| MDG | Moisture Density Gauge |
| MDS | Meteorological Distribution System |
| MDSD | Maximum Daily Snowmelt Discharge |