HR: 0800h
AN: A51C-0797 [Abstracts]
TI: Performance of an airborne White-Light Optical Particle Counter with an LED light source
AU: * Wollny, A G
EM: Adam.Wollny@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, R/AL 7, Boulder, CO 80305
United States
AU: * Wollny, A G
EM: Adam.Wollny@noaa.gov
AF: CIRES,
University of Colorado, 216 UCB, Boulder, CO 80309
United States
AU: Simons, C
EM: Craig.Simons@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, R/AL 7, Boulder, CO 80305
United States
AU: Simons, C
EM: Craig.Simons@noaa.gov
AF: CIRES,
University of Colorado, 216 UCB, Boulder, CO 80309
United States
AU: Brock, C A
EM: Charles.A.Brock@noaa.gov
AF: NOAA Aeronomy Laboratory, 325 Broadway, R/AL 7, Boulder, CO 80305
United States
AU: Brock, C A
EM: Charles.A.Brock@noaa.gov
AF: CIRES,
University of Colorado, 216 UCB, Boulder, CO 80309
United States
AU: Wilson, J C
EM: jwilson@du.edu
AF: University of Denver, 2199 S. University Blvd., Denver, CO 80208
United States
AB:
The White-Light Optical Particle Counter (WLOPC) was designed to measure the particle size distribution in the range from 0.8
to 8 um on board the NOAA WP-3D research aircraft. Supermicron particles are quantitatively sampled using a Low Turbulence
Inlet (LTI). To minimize particle losses during transport, the WLOPC optical detector is placed close to the LTI, while the
control unit with computer, electronics, flow system and power supply is placed two meters away. The sample flow provided by
the LTI is about 80 liter per minute by volume (lpmv), of which 4 lpmv are extracted to the WLOPC. To control the relative
humidity this sample flow can be heated up to 50§C. The sample air enters the detection chamber through a nozzle sheathed by
an addition flow of 4 lpmv. The resulting particle beam crosses a focused light beam from a broad-spectrum light-emitting
diode (LED). The scattered light is reflected by an elliptical mirror onto a photo multiplier tube (PMT). The choice of a
white light source and a large solid angle reduces the sensitivity to particle shape and refractive index and produces a
monotonic output as a function of particle diameter. The PMT output is converted by a preamplifier and a logarithmic
amplifier and analyzed for pulse amplitude. The pulse amplitude is calibrated using monodisperse particles of different
compositions and binned into 30 channels. The first ambient measurements by the WLOPC were made on the NOAA WP-3D during the
Intercontinental Transport and Chemical Transformation - New England Air Quality Study (ITCT-NEAQS 2004) in July and August
2004. Preliminary data from this mission will be presented.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting