- atmospheric radioactivity
- atmospheric refraction
- atmospheric remote sensing
- atmospheric science
- atmospheric sounding and observing
- atmospheric stability
- atmospheric subdivision
- atmospheric suspended matter
- atmospheric thermodynamics
- atmospheric trace gas
- atmospheric transmission model
- atmospheric transmissivity
- atmospheric transparency
- atmospheric turbidity
- atmospheric turbulence
- atmospheric wave
- atmospheric window
- atmospherics
- attenuation coefficient
- attenuation cross section
- aurora
- aurora australis
- aurora borealis
- autographic records
- automatic data processing
- automatic meteorological station
- available potential energy
- available wind energy
- average wind velocity
- aviation area forecast
- aviation climatology
- aviation forecast
- aviation meteorological code
- aviation meteorological element
- aviation meteorological information
- aviation meteorological observation
- aviation meteorological support
- axis of jet stream
- azimuth averaging
- azimuth resolution
- Azores high
- background pollution observation
- backing wind
- backscatter ultraviolet technique
- backscattering
- backscattering cross section
- backward tilting trough
- balance equation
- ball lightning
- ballistic air density