m=1.33 1.45 1.59

M=1.33 1.45 1.59

0.1 µm

0.2

0.3

0.4

White light

0.5 µm

0.6

0.7

0.8

1.0 µm

X=10

M=1.33 1.45 1.59M=1.33 1.45 1.59

Deshler, T., Observations for Chemistry (In Situ): Particles, article for Encyclopedia of Atmospheric Science, Academic Press, 2002.

CR cl()d fl(,)d 2 2 i1(x, m,) i2 (x, m,) I() QE() d

0.3 m

0.7 m

fl2

fl2

cl2

cl2

Wyoming Optical Particle Counter, r > 0.2 - 10.0 m

Whitelight

PumpPMTs PHA

ProcessorOptical Chamber

Aerosolin

CR cl()d fl(,)d 2 2 i1(x, m,) i2 (x, m ,) I() QE() d

0.3 m

0.7 m

fl2

fl2

cl2

cl2

Sources of Error

Size Chromatic nature of light sourceAerosol index of refraction and shapeUniformity of illuminationPMT response – pulse width broadening

Number concentrationFlow rateCoincidencePoisson counting uncertainty

Deshler, T., M. E. Hervig, D. J. Hofmann, J. M. Rosen, and J. B. Liley, Thirty years of in situ stratospheric aerosol size distribution measurements from Laramie, Wyoming (41N), using balloon-borne instruments, J. Geophys. Res., 108(D5), 4167, doi:10.1029/2002JD002514, 2003

1971 - 1990 1990 - present

PostEl Chichon

Low Gain

Mid Gain

High Gain

Eidhammer, T., D. C. Montague, and T. Deshler, Determination of Index of Refraction and Size of Supermicrometer Particles from Light Scattering Measurements at Two Angles, J. Geophys. Res., in press, May 2007.

SAGE II

HALOE

Deshler et al., JGR, 2003

0

2 ),,( drdr

dnmrQr

Comparison with SAGE II Extinction.

Kovilakam and Deshler, 2014,

0

2 ),,( drdr

dnmrQr

Comparison with HALOE Extinction.

Kovilakam and Deshler, 2014,

0

2 ),,( drdr

dnmrQr

0.1 1 10100

101

102

103

104

105

0.1 1 10100

101

102

103

104

105

EM OPC

UW OPC

b)C

ount

er R

espo

nse

Radius (µm)

Indices of refraction

1.350 1.400 1.450 1.500 1.592

23-123°, 405 nm

a) Index of refraction = 1.45

405 nm EM OPC 685 nm EM OPC White light UW OPC

Radius (µm)