Characterization of Arctic ice cloud properties observed during ISDAC

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Jouan, Caroline, Girard, Eric, Pelon, Jacques, Gultepe, Ismail, Delanoë, Julien, Blanchet, Jean-Pierre
• Other Authors: TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre ESCER, Université du Québec à Montréal = University of Québec in Montréal (UQAM), SPACE - LATMOS, Environment and Climate Change Canada, Natural Sciences and Engineering Research Council of Canada (NSERC),Fonds Québécois de la Recherche sur la Nature et la Technologie (FQRNT),Centre National d’Etudes Spatiales (CNES)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: Arctic; ISDAC; Airborne measurements; Cloud-aerosol interactions; Ice cloud; Remote sensing; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; polar night
• Online Access: https://hal.archives-ouvertes.fr/hal-00769659; https://hal.archives-ouvertes.fr/hal-00769659/document; https://hal.archives-ouvertes.fr/hal-00769659/file/Jouan_et_al-2012-Journal_of_Geophysical_Research__Solid_Earth_%281978-2012%29.pdf; https://doi.org/10.1029/2012JD017889

International audience Extensive measurements from ground-based sites and satellite remote sensing (CloudSat and CALIPSO) reveal the existence of two types of ice clouds (TICs) in the Arctic during the polar night and early spring. The first type (TIC-2A), being topped by a cover of nonprecipitating very small (radar unseen) ice crystals (TIC-1), is found more frequently in pristine environment, whereas the second type (TIC-2B), detected by both sensors, is associated preferentially with a high concentration of aerosols. To further investigate the microphysical properties of TIC-1/2A and TIC-2B, airborne in situ and satellite measurements of specific cases observed during Indirect and Semi-Direct Aerosol Campaign (ISDAC) have been analyzed. For the first time, Arctic TIC-1/2A and TIC-2B microstructures are compared using in situ cloud observations. Results show that the differences between them are confined in the upper part of the clouds where ice nucleation occurs. TIC-2B clouds are characterized by fewer (by more than 1 order of magnitude) and larger (by a factor of 2 to 3) ice crystals and a larger ice supersaturation (of 15-20%) compared to TIC-1/2A. Ice crystal growth in TIC-2B clouds seems explosive, whereas it seems more gradual in TIC-1/2A. It is hypothesized that these differences are linked to the number concentration and the chemical composition of aerosols. The ice crystal growth rate in very cold conditions impinges on the precipitation efficiency, dehydration and radiation balance. These results represent an essential and important first step to relate previous modeling, remote sensing and laboratory studies with TICs cloud in situ observations.