B

LWC SWEEPS 29.5-32.5 pm

LWC SWEEPS 12.9-17.6 pm

0.2 0.4 0.6 0.8 1.0 1.2 Tunnel Reference LWC (g m-3)

1.6

1.4

1.2

3

1.0

-

r g

0.8

< 1

0.6

r-g

0.4

0.2

0.0

LWC SWEEPS 29.5-32.5 pm

67 ms-1 position #1 100 ms-1 position #1 67 ms-1 position #2 100 ms-1 position #2

Tunnel Reference LWC (g m-3)

67 ms-1 position #1 100 ms-1 position #1 67 ms-1 position #2 100 ms-1 position #2

Tunnel Reference LWC (g m-3)

MVD SWEEPS 12.9-236 pm

I 06

o 100 ms-1 position #1 x 67 ms-1 position #2

s 100 ms-1 position #2

0 50 100 150 200 250

Figure 4.6 PMS King hot-wire probe: (a) comparisons to tunnel reference LWCs for low median volume diameter, MVD, (12.9-17.8 pm); (b) corresponding comparisons for intermediate MVD (29.5-32.5 pm); (c) the ratio of King probe LWC to tunnel LWC as a function of MVD (from Strapp et al. 2003).

Figure 4.7 Response of various optical array probes run at 67 m s 1, 0.84 g m 3 with a median volume diameter (MVD) of 32.9 pm (from Strapp et al. 2003).

at aircraft speeds or, alternatively, the electronic size-response roll-off of the probe with airspeed should be factored into the calibration.

OAPs can also be laboratory tested. Strapp et al. (2001) show how a PMS 2-DC probe's ability to size accurately and its associated depth of field can be assessed in a laboratory setting. Korolev et al. (1998a) provides a theoretical discussion of the problems associated with particle imaging, and calculations of the digitization and out-of-focus imaging effects on size distributions.

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