Planet Boundary Layer sulfur dioxide (PBL-SO2) derived from Ozone Monitoring Instrument (OMI) are compared with
in-situ measurements from Differential Optical Absorption Spectroscopy (DOAS) and gas analyzer observations at three
sites in Beijing (Jan-Dec, 2007) and Hebei province (Jan-May, 2007). We use an Air Mass Factor (AMF) lookup table,
which was calculated via Linearized Discrete Ordinate Radiative Transfer (LIDORT) model, to convert OMI PBL-SO2
slant column density to vertical column density. Co-locate Lidar (UV) aerosol extinction profiles are used to correct the
effect of aerosol. Results show that, AMF decreases less than 3% with the increasing solar zenith angle from 0° to 45°,
AMF is more sensitive to surface albedo and the viewing zenith angle. AMF reduces by 6% with the increasing Ozone density from 275DU to 325DU. Normally, absorption aerosol reduces AMF and scattering aerosol increases AMF, aerosol profiles are critical to AMF estimation. Under very clear conditions, from winter to later spring, OMI observed SO2 values are underestimated by 3.6ppbv to 20ppbv, but in reasonable agreement with in-situ measurements. Because
of the effects of Sub-pixel cloud contamination, long slant path (higher solar zenith angles or viewing zenith angles),
differences in aerosol types and large Aerosol Optical Depth (AOD), direct comparisons between the OMI retrieval and
the in situ measurements show that the correlation is low and the differences vary with months, while averaging over half
a month can significantly reduces the bias.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.