Speaker
Description
Stratospheric aerosols play a key role in atmospheric chemistry and climate. They are considered a catalyst for ozone depletion, serve as condensation nuclei for polar stratospheric cloud formation, and, in large quantities, have a short-term impact on the Earth's radiative budget. The aerosol effects depend strongly on the aerosol particle size distribution (PSD). Despite its importance, available observations on aerosol particle size are rather limited, restricting the knowledge of chemical and climate aerosol feedback mechanisms. An extension of the PSD data set is therefore desirable.
We retrieve the PSD from SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Cartography) limb observations. The retrieved PSD profiles are compared with in-situ balloon-borne measurements from Laramie, Wyoming, and SAGE III-M3M (Stratospheric Aerosol and Gas Experiment III onboard the Russian Meteor-3M) retrievals over the northern hemisphere. Assuming a fixed number density profile, the median radius and geometric standard deviation from SCIAMACHY, balloon-borne measurements, and SAGE III agree within about 27 % and 10 %, respectively. A more accurate a priori number density profile can usually reduce the differences by more than a factor of two.
The simultaneous retrieval of three PSD parameters, i.e., median radius, geometric standard deviation, and number density, from SCIAMACHY limb observations can potentially reduce retrieval errors. The median radius, geometric standard deviation, and the number density deviate by less than 15 %, 6 %, and 40 % from the balloon-borne measurements. Actual comparisons to PSD retrievals from SAGE III-M3M will be presented.
