NOAA CLAP Continuous Light Absorption Photometer Why bother
NOAA CLAP: Continuous Light Absorption Photometer • • • Why bother with a new instrument? - lost data due to overloaded filters - unheated sample block - leak-prone filter holder - "black box" internal processing of PSAP User interface – KISS (Keep It Simple, Stupid!) - filter change button and status indicator - flow control - primary user interface is through 'cpd' software Data output optimized for machine processing Firmware can be upgraded in the field, remotely from Boulder Characterization - internal construction (photos) - noise vs. averaging time - LED intensity - planned open source release of drawings, schematics, code J. Ogren 04/29/09
NOAA CLAP – Assembled Product J. Ogren 04/29/09
NOAA CLAP – Light Source Internal View J. Ogren 04/29/09
NOAA CLAP – Assembly Details J. Ogren 04/29/09
LED spectral output - CLAP s/n 10. 002 0. 010 blue (peak 462 nm, avg 463 nm) 0. 009 green (peak 522 nm, avg 529 nm) normalized output 0. 008 red (peak 654 nm, avg 654 nm) 0. 007 0. 006 0. 005 0. 004 0. 003 0. 002 0. 001 0. 000 350 J. Ogren 04/29/09 400 450 500 550 600 wavelength (nm) 650 700 750
CLAP and PSAP noise vs. Averaging Interval Smoothers: PSAP=4 -sec boxcar, CLAP=3 -sec 1 -pole/4 -pass 10. 00 green PSAP#094 (0. 11 @ 60 s) green PSAP#106 (0. 09 @ 60 s) blue CLAP#001 (0. 18 @ 60 s) noise (Mm-1, 1 -σ) green CLAP#001 (0. 15 @ 60 s) 1. 00 red CLAP#001 (0. 11 @ 60 s) 0. 10 0. 01 1 J. Ogren 04/29/09 10 averaging interval (s) 100
CLAP (new) CLAP vs. PSAP Comparison sap (Mm-1) J. Ogren 04/29/09 PSAP (old)
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