Towards a combined SAGE II and SCIAMACHY aerosol dataset and implications for stratospheric aerosol trend analysis over East Asia

Abstract

Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) limb observation data are used to retrieve stratospheric aerosol extinction profiles. The retrieved aerosol profiles are compared with Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol data records. The comparisons are made over the period 2003–2004. The results show that the SCIAMACHY aerosol profile retrievals exhibit general agreement with the coincident SAGE II data records. In the 15–35 km altitude range, the percentage differences between the SCIAMACHY-retrieved and SAGE II–measured zonal mean aerosol extinction profiles are less than 20% for the 20–30°N and 30–40°N latitude zones, and less than 25% for the 40–50°N zone. The stratospheric aerosol optical depths in this altitude range calculated from SCIAMACHY retrievals are in good agreement with SAGE II measurements, with present differences less than 6% for the three latitude zones. The aerosol retrievals from SCIAMACHY observations are combined with the SAGE II aerosol data records, form a long-term data-set for the period 2000–2010. Using the combined SAGE II and SCIAMACHY data-set, the variation trends of the stratospheric aerosol layer over East Asia (20–50°N, 70–150°E) are analyzed. The results indicate that the stratospheric aerosols have a significant trend of increase over East Asia during 2000–2010. The stratospheric aerosol optical depths increase by about 5% per year over the 11-yr period. The increase in stratospheric aerosols is found to be obviously related to moderate volcanic eruptions.

Keywords

• Aerosol
• stratosphere
• trend
• SCIAMACHY
• SAGE II