A21F-3106:
Analysis of the Interaction and Transport of Aerosols with Cloud or Fog during Dragon Campaigns from Aeronet and Satellite Remote Sensing
Tuesday, 16 December 2014
Thomas F Eck1, Brent N Holben1, Jeffrey S. Reid2, Joel Schafer1, David Matthew Giles1, Jhoon Kim3, Young J Kim4, Itaru Sano5, Peng Lynch2, Kenneth E Pickering1, James H Crawford6, Alexander Sinyuk1, Alexander Smirnov1 and Nathan Trevino7, (1)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2)Naval Research Lab, Monterey, CA, United States, (3)Yonsei University, Seoul, South Korea, (4)GIST Gwangju Institute of Science and Technology, Gwangju, South Korea, (5)Kinki University, Osaka, Japan, (6)NASA Langley Research Center, Hampton, VA, United States, (7)San Joaquin Valley Air Pollution Control District, Fresno, CA, United States
Abstract:
Ground-based remote sensing observations from Aerosol Robotic Network (AERONET) sun-sky radiometers have recently shown several instances where cloud-aerosol interaction had resulted in modification of aerosol properties and/or in difficulty identifying some major pollution transport events due to aerosols being imbedded in cloud systems. AERONET has established Distributed Regional Aerosol Gridded Observation Networks (DRAGON) during field campaigns that are short-term (~2-3 months) relatively dense spatial networks of ~15 to 45 sun and sky scanning photometers. Recent major DRAGON field campaigns in Japan and South Korea (Spring 2012) and California (Winter 2013) have yielded observations of aerosol transport associated with clouds and/or aerosol properties modification as a result of fog interaction. Analysis of data from the Korean and Japan DRAGON campaigns shows that major fine-mode aerosol transport events are sometimes associated with extensive cloud cover and that cloud-screening of observations often filter out significant pollution aerosol transport events. The Spectral De-convolution Algorithm (SDA) algorithm was utilized to isolate and analyze the fine-mode aerosol optical depth signal for these cases of persistent and extensive cloud cover. Satellite retrievals of AOD from MODIS sensors were also investigated to assess the issue of detectability of high AOD events associated with high cloud fraction. AERONET is updating the cloud-screening algorithm applied to AOD data in the upcoming Version 3 database. Comparisons of cloud screening from Versions 2 and 3 of cases with high AOD associated with clouds will be studied. Additionally, extensive fog that was coincident with aerosol layer height on some days in both Korea and California resulted in large increases in fine mode aerosol radius, with a mode of cloud-processed or residual aerosol of radius ~0.4-0.5 micron sometimes observed. Cloud processed aerosol may occur much more frequently than AERONET data suggest due to inherent difficulty in observing aerosol properties near clouds from remote sensing observations. These biases of aerosols associated with clouds are even greater for passive satellite remote sensing retrievals of aerosol properties near clouds due to sub-pixel cloud contamination and 3-D effects issues.
