Quasi-Lagrangian measurements of nitric acid trihydrate formation over Antarctica

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Ward, S.M., Deshler, T., Hertzog, Albert
• Other Authors: Department of Atmospheric Science Laramie, University of Wyoming (UW), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Austral; McMurdo Station; Antarc*; Antarctica
• Online Access: https://hal.archives-ouvertes.fr/hal-01087722; https://hal.archives-ouvertes.fr/hal-01087722/document; https://hal.archives-ouvertes.fr/hal-01087722/file/2013JD020326.pdf; https://doi.org/10.1002/2013JD020326

International audience In 2010, the joint French-United States Concordiasi project released 19 long-duration superpressure balloons from McMurdo Station, Antarctica. Four of these balloons carried a gondola with particle counters and temperature sensors to measure polar stratospheric clouds. One gondola spent 5 days at stable temperatures between equilibrium temperatures for nitric acid trihydrate (NAT) and for supercooled ternary solution droplets. Sporadic particles with radii between 0.46 µm and 4.5 µm were measured in a small fraction of the measurements. At these times the corresponding size distributions and total particle volumes were consistent with NAT. Although the fraction of these observations was less than 3%, their frequency increased with time over the 5 days. From this frequency the NAT nucleation rate at 3°C below T NAT was estimated to be 2 × 10-4 m-3 s-1 ± 60% for these late winter austral NAT observations at a potential temperature of 410-415 K. Interspersed with these measurements of polar stratospheric cloud particles consistent with NAT were many more measurements of particles consistent with background stratospheric aerosol indicating that the polar stratospheric clouds sampled were highly discontinuous. Key Points Quasi-Lagrangian measurements of polar stratospheric cloud particles Balloon-borne measurements of nitric acid trihydrate formation © 2013. The Authors.