AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Remote Sensing Sulfuric Acid Droplets in the Stratosphere
Wenbo Sun, GORDEN VIDEEN, Yongxiang Hu, Rosemary Baize, Science Systems and Applications, Inc.
Abstract Number: 23 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Stratospheric aerosols are mostly sulfuric acid droplets with diameters smaller than one micron. They play important roles in the chemical balance of the stratosphere and can have a significant impact on Earth’s radiation balance. Because of their high altitude, small size and low optical thickness, stratospheric droplets of sulfuric acid are difficult to detect with either in-situ or remote-sensing methods. Recently, Sun et al. (2014) reported a novel method for detecting cloud particles in the atmosphere. A distinct feature is the angle of linear polarization (AOLP) of backscattered solar radiation. The dominant backscattered electric field from the clear-sky Earth-atmosphere system is nearly parallel to the Earth surface. However, when clouds are present, this electric field can rotate significantly away from the parallel direction. Model results and satellite data both demonstrate that this polarization feature can be used to detect super-thin cirrus clouds having an optical depth of only ~0.06 and super-thin liquid water clouds having an optical depth of only ~0.01. We can use this method to probe the stratosphere through limb detection. We demonstrate this using the radiative-transfer model developed in Sun and Lukashin (2013), in which we simulated the backscattered solar light’s AOLP from pure molecular atmosphere and the atmosphere including the stratospheric droplets of sulfuric acid.
References Sun, W. and Lukashin, C. (2013) Atmos. Chem. Phys. 13, 10303- 10324. Sun, W., Videen, G., and Mishchenko, M.I. (2014) Geophy. Res. Lett. 41, 688-693.