Abstract ID: 710

Vertical profiles of aerosol properties over Amazonia observed with LIDAR

Knowledge on the vertical distribution of aerosols in Amazonia is an important information for the understanding of the local and global influence of aerosol on radiation budget and cloud formation. Profiling of the troposphere in terms of aerosol properties can either be done by in-situ instruments loaded on, e.g., aircrafts, or by the use of remote sensing instruments. LIDAR (Light Detecting And Ranging) is an appropriate remote sensing instrument to measure vertical profiles of aerosol properties up to the stratosphere. Pulsed laser light is vertically emitted into the atmosphere and is backscattered by molecules and particles. The backscattered light is detected with high temporal resolution to obtain vertically resolved information. This allows the determination of the height of the planetary boundary layer top, as well as the cloud base heights and the detection of lofted aerosol layers. In the framework of the European Integrated project on Aerosol Cloud Climate and Air Quality Interactions (EUCAARI), long-term LIDAR observations have been performed in the central portion of the Amazon basin. The site is located 50 km north from the city of Manaus, in Brazil. These observations have been made with the multiwavelength-polarization Raman LIDAR PollyXT of the Leibniz Institute for Tropospheric Research. With this remote sensing instrument, vertical profiles of backscatter coefficient, extinction coefficient and particle depolarization can be determined at different wavelengths. This feature allows the retrieval of microphysical and optical properties like volume concentration, effective radius, complex refractive index and single scattering albedo at different height levels via an inversion algorithm. The distinction between different aerosol types is therefore possible. The measurements started in January 2008 and will cover the wet and the dry season in 2008. Beside a brief introduction into the theory of LIDAR, observations examples from the wet season will be presented in this work. At these examples, the potentials of the performed measurements, including the retrieval of microphysical properties, will be discussed. If possible, observations of aerosol conditions in the dry season will be presented too.

Session:  Feedbacks to Climate - Emissions of natural and biomass burning particulates from vegetation and their effects on ecosystems and climate.

Presentation Type:  Oral