https://cdn.earthdata.nasa.gov/conduit/upload/5182/KeywordsCommunityGuide_Baseline_v1_SIGNED_FINAL.pdf draft 2025-07-25 https://gcmd.earthdata.nasa.gov/KeywordViewer/scheme/instruments/81471966-b42c-45c9-b060-6d707dd70519 FPCAS Date=2025-12-05 User Id=tstevens User Note=added new Instrument keyword Date=2025-12-05 User Id=system System Note=Added broader relation from FPCAS [81471966-b42c-45c9-b060-6d707dd70519] to Spectrometers/Radiometers [ecd58f82-8f96-45e1-9547-dd4a02291bd9] Principal Investigators: James E. Dye (303) 497-8944 Darrel Baumgardner (303) 497-1054 FAX (303) 497-8181 Organization: National Center for Atmospheric Research 1850 Table Mesa Drive Boulder, Co 80307 Principle of Operation: The Forward Scattering Spectrometer Probe (FSSP) Model 300 sizes particles by measuring the amount of laser light scattered from angles of 4 to 12&degree; by aerosol particles in situ as they pass through a focused laser beam. Comparison of voltage outputs from the signal detector and a masked slit detector is used to electro-optically define the sample area. Fig. 1 shows the configuration of the instrument. The instrument system is composed of two parts: (l) a Particle Measuring Systems model FSSP-300 aerosol spectrometer, and (2) a data acquisition and recording system. The FSSP-300 aerosol spectrometer is located on the front of the starboard spear pod of the ER-2. The data acquisition and recording system is part of the package that houses the FPCAS aerosol spectrometer located in the bottom, rear portion of the starboard spear pod of the ER-2. The FSSP-300 aerosol spectrometer sizes particles in the 0.4 to 20 micron diameter size range (depending on the refractive index of the aerosol particles measured) in the free air stream outside the ER-2. The measured particles are divided into 31 size intervals with more resolution at smaller sizes. 2025-12-05T18:21:36.010Z