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Updated: Aug 2, 2026

Extraction and Characterization of Surfactants from Atmospheric Aerosols
Published on: April 21, 2017
Nitric acid trihydrate (NAT) in polar stratospheric clouds
C Voigt1, J Schreiner, A Kohlmann
1Max-Planck-Institut für Kernphysik, Division of Atmospheric Physics, Post Office Box 103 980, D-69029 Heidelberg, Germany.
Polar stratospheric clouds contain nitric acid trihydrate (NAT) particles, existing above ice formation temperatures. These NAT particles contribute to ozone depletion in polar regions.
Area of Science:
- Atmospheric Chemistry
- Polar Meteorology
Background:
- Polar stratospheric clouds (PSCs) play a critical role in polar ozone depletion.
- Understanding PSC composition is crucial for atmospheric modeling.
Purpose of the Study:
- To investigate the composition of PSCs.
- To confirm the existence of nitric acid trihydrate (NAT) particles in PSCs.
Main Methods:
- Balloon-borne instrumentation launched from Kiruna, Sweden.
- In-situ measurements of cloud layers at altitudes of 20-24 km.
Main Results:
- PSC layers were observed between 20 and 24 km altitude.
- Particle analysis revealed a significant fraction of nitric acid trihydrate (NAT) particles.
- NAT particles were present at temperatures above ice formation point.
Conclusions:
- Solid NAT particles exist in PSCs at temperatures above ice formation.
- NAT particle presence facilitates chlorine activation, leading to ozone destruction.
- This finding is particularly relevant for early and late polar winter ozone depletion.
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