Investigation of Trace Gas to Aerosol Relationships over Biomass Burning Areas using Daily Satellite Observations
Wagner, Thomas; Penning de Vries, Marloes; Zörner, Jan; Beirle, Steffen
MPI for Chemistry, GERMANY
The quantification and characterization of aerosols from space is a great challenge. Especially in the presence of clouds and over land surfaces, it is often difficult to distinguish the signal of aerosol scattering from scattering by cloud particles or surface reflection.
Instead of deriving aerosol properties directly, satellite observations of tropospheric trace gases, which have the same emission sources as the aerosols can be used to derive aerosol information. Such observations have two potential advantages: First, from the composition of trace gases, additional information on the aerosol type can be derived. Second, such observations are possible in the presence of clouds (although usually with reduced sensitivity if the trace gas is located below the cloud).
In this feasibility study we investigate the relationship between satellite observations of trace gas (CO, NO2, HCHO, CHOCHO) and AOD (measured from satellite or ground). We also include in our comparison satellite observations of the so called UV aerosol index (UVAI), which is an indicator of the aerosol absorption. Like the trace gas observations, also the UVAI can be retrieved in the presence of clouds.
The focus of our study is on aerosol emissions from biomass burning, which have a strong impact on the atmospheric energy budget through direct and indirect effects. We perform correlation analyses for selected AERONET stations and also for larger biomass burning areas by taking into account satellite observations of fire counts.
Two main questions will be addressed in our study: a) How well can aerosols be characterised based on satellite observations of trace gases and the UVAI? b) What is the fraction of additional satellite observations (compared to only clear sky observations) of trace gases and the UVAI that can yield useful information on aerosols in the presence of clouds?