New Instrument Development

 

OVERVIEW

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The Ames Sunphotometer/Satellite team is exploring advanced instrument concepts and investigating their feasibility. The advanced concepts, called Spectometers for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) are smaller than our current airborne sunphotometer (AATS-14) while extending AATS-14 capabilities in two ways:

• Sky scanning: By adding the capability to measure the angular distribution of sky brightness, the new instrument concepts would enable retrievals of aerosol type (via complex refractive index and shape) and aerosol size distribution extending to larger sizes than are possible with direct-beam sunphotometery. These capabilities, currently provided on the ground by NASA's AERONET network, would be extremely valuable in an airborne instrument.
• Wavelength resolution: By using a spectrometer in place of the discrete photodiodes and filters of AATS-14, the new concepts would improve accuracy of water vapor and ozone measurement, enable measurements of other gases (e.g., NO₂, SO₂) and improve accuracy of aerosol measurements via better aerosol-gas separation.

Above photos: show an advanced concept for an airborne sun-sky spectrometer, our gound prototype (4STAR-Ground), and data from 4STAR-Ground. Click on photos to enlarge.

4STAR research is being conducted as a collaboration between NASA Ames and Battelle, Pacific Northwest Division.