Was macht Düngemittel in 18 km Höhe? – Ammoniak und Ammoniumnitrat in der oberen Troposphäre

The ATAL (Asian Tropopause Aerosol Layer), a layer of aerosol particles at 13–18 km altitude, reaches from East Asia to the Eastern Mediterranean and is formed each year during the period of the Asian Monsoon. A large amount of the ATAL particles consists of solid ammonium nitrate. These particles have their origin in agricultural emissions of ammonia in Northern India and Pakistan. NH3 is transported to high altitudes by strong convection during thunderstorms and neutralizes available HNO3 to form ammonium nitrate. Due to their effective heterogeneous ice nucleation potential, the solid ammonium nitrate particles can affect the formation and radiative properties of cirrus clouds and, thus, have influence on climate.