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More information on aerosol particles (size, refractive index) can be obtained by measuring scattered light in addition to the direct solar beam. Entrance aperture. Optical fiber. Sun-tracking head. Altair UAV. “Heart” of prototype is a Spectrometer: Zeiss MCS with Tec5 Electronics
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More information on aerosol particles (size, refractive index) can be obtained by measuring scattered light in addition to the direct solar beam Entrance aperture Optical fiber Sun-tracking head Altair UAV • “Heart” of prototype is a Spectrometer: • Zeiss MCS with Tec5 Electronics • Hamamatsu CCD S7031-1006 1044x64 pixels • Spectral range: l=220-1000 nm • Spectral distance of pixel: Dl ~ 0.8 nm • Resolution: Dl =1.7 - 2.5 nm (Dimensions in mm) An airborne instrument that measures a continuous spectrum of the direct solar beam and of the scattered sunlight as a function of angular distance from the Sun will deliver considerably more information on atmospheric aerosols and gases but does not currently exist. Towards an Autonomous Airborne Sun/Sky Scanning Spectrometer Beat Schmid (SGG/BAER), Nicholas Truong (SGG/BAER), Teck Meriam (SGG/BAER*), Philip Russell (SGG), and Jens Redemann (SGG/BAER) *Now at KLA Tencor Atmospheric aerosols (particles 10 nm to 10 mm) play a crucial role in the Earth’s radiation balance and may hold the key to combating global warming. However, more knowledge is needed about aerosol sources, distributions and properties. This requires continuous observations from satellites, networks of ground-based instruments, and dedicated field experiments. The existing Ames airborne tracking sunphotometers (AATS) make sunlight transmission measurements at 6 or 14 discrete wavelengths from which we derive information on aerosols, water vapor and ozone. The AATS measuements have been used extensively to validate measurements from satellite-, aircraft- and surface-based instruments. NASA Ames has been the world leader in airborne sunphometry since 1985. Instrument Block Diagram The AERONET (AErosol RObotic NETwork) program is a global, federated ground-based network of Sun/Sky radiometers initiated by NASA. In the project we build a ground-based prototype to address key technical challenges we encounter when designing the smaller, lighter, fully autonomous, more capable instrument described above. The challenges are: a) Dynamic range of the detection system, b) Suppression of unwanted stray light when measuring sky radiance a few degrees away from the Sun, c) In-flight self-cleaning of the optical window. Spectra from various light sources NASA Ames Airborne Sunphotometer-Satellite Group Major Aerosol Field Campaigns, 1996-2004 TARFOX, 1996 ICARTT, 2004 SOLVE II, 2003 ADAM, 2003 EVE, 2004 ACE-Asia, 2001 CLAMS, 2001 ACE-2, 1997 ARM Aerosol IOP, 2003 PRIDE, 2000 SAFARI, 2000