HR: 1340h
AN: A43D-1565    [Abstracts]
TI: Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR): Airborne Concepts and Ground Prototype Measurements
AU: Russell, P B
EM: Philip.B.Russell@nasa.gov
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035-1000, United States
AU: Schmid, B
EM: beat.schmid@pnl.gov
AF: PNNL/Battelle Pacific Northwest Division, 902 Battelle Boulevard, Richland, WA 99352, United States
AU: * Flynn, C
EM: Connor.Flynn@arm.gov
AF: PNNL/Battelle Pacific Northwest Division, 902 Battelle Boulevard, Richland, WA 99352, United States
AU: Dunagan, S E
EM: Stephen.E.Dunagan@nasa.gov
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035-1000, United States
AU: Johnson, R R
EM: Roy.R.Johnson@nasa.gov
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035-1000, United States
AU: Redemann, J
EM: jredemann@mail.arc.nasa.gov
AF: Bay Area Environmental Research Institute, 560 Third St. West, Sonoma, CA 95476, United States
AU: Livingston, J
EM: jlivingston@mail.arc.nasa.gov
AF: SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, United States
AB: A collaboration between NASA Ames Research Center and Battelle Pacific Northwest Division is exploring new instrument concepts that combine sky scanning and spectroscopy with the direct sun transmission measurement capabilities of previous instruments like the NASA Ames Airborne Tracking Sunphotometers (AATS). Additional technical goals are to reduce instrument size, weight, and power requirements while increasing autonomy, so as to permit operation on a wider range of aircraft, including unmanned aerial vehicles (UAVs). The overall science goal for the new instruments is to improve knowledge of atmospheric constituents and their links to climate using a variety of airborne measurement approaches including satellite validation. The sky scanning capability will enable retrievals of aerosol type (via complex refractive index and shape) and aerosol size distribution extending to larger sizes than attainable by direct-beam sunphotometry alone. The spectroscopic capability will improve measurements of gas constituents (e.g., H2O, O3, NO2, SO2) . Concepts explored to date for an airborne Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR-Air) include using fiber optics to link a spectrometer inside the aircraft to optical entrance ports in a relatively small tracking/scanning head outside the aircraft. 4STAR feasibility depends on overcoming three technological hurdles: 1. Maintaining calibration to 1% stability over a period of months. 2. Demonstrating stray light rejection to permit measuring skylight within a few degrees of the sun. 3. Devising a fiber optic coupling that maintains 1% calibration stability with as many as possible of the following desirable characteristics: detachable during assembly before calibration; detachable between calibration and scientific measurements; rotatable during measurements. To investigate ways to overcome these hurdles we have developed a ground-based prototype, 4STAR-Ground. To date 4STAR-Ground has been calibrated with an integrating sphere, and its performance has been characterized in many tests, including comparisons of its sun-tracking and sky-scanning measurements to AATS-14 and an AERONET Cimel sun-sky photometer, respectively. This poster includes concepts for 4STAR-Air and results of the above 4STAR-Ground measurements.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0360 Radiation: transmission and scattering
DE: 0394 Instruments and techniques
DE: 1640 Remote sensing (1855)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting