The Dedicated Aerosol Retrieval Experiment (DARE). Scientific requirements for a dedicated satellite instrument to measure atmospheric aerosols

摘要

DARE (Dedicated Aerosol Retrieval Experiment) is a study to design an instrument for accurate remote sensing of aerosol properties from space. DARE combines useful properties of several existing instruments like TOMS, GOME, ATSR and POLDER. It has a large wavelength range, 330 to 1000 nm, to discriminate between aerosol types. The wide swath will enable daily global coverage of the earth at a pixel size of 5 x 5 km~2 (nadir). The instrument will have three viewing angles, looking forward, at nadir and backward. These angles will facilitate the separation of atmospheric and surface contributions to the satellite signal. Multiple views will also help to determine the height and thickness of aerosol layers. Full polarization information will be measured for at least one of the viewing angles and at many of the available wavelengths. Polarization helps to separate surface/atmosphere signals and it contains valuable information on the shape of aerosol particles. Cloud detection will be enhanced by adding thermal infrared detectors at the same spatial resolution. Simulations and tests were performed to optimize the current design of the instrument. The expected performance of DARE in comparison to other instruments will be discussed.