uc santa cruz @ vocals?
DESCRIPTION
UC Santa Cruz @ VOCALS?. PI: Patrick Chuang Instrument: Phase-Doppler interferometer Measures cloud drop size velocity inter-drop spacing on a single drop basis. Size range: 3 to 150 um. PDI mounted on the CIRPAS TwinOtter. Pre-flight testing of the PDI. - PowerPoint PPT PresentationTRANSCRIPT
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UC Santa Cruz @ VOCALS?
• PI: Patrick Chuang• Instrument: Phase-Doppler
interferometer• Measures cloud drop
– size– velocity – inter-drop spacing
on a single drop basis.• Size range: 3 to 150 um
PDI mounted on the CIRPAS TwinOtter
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Pre-flight testing of the PDI
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Sample data from the Marine Stratocumulus Experiment (MASE). Note the occurence of bi-modal distributions most likely caused by collision-coalescence, a key process in drizzle formation.
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Example of bimodal distribution in stratocumulus clouds.
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Comparison of view volume diameter derived from in situ measurements and theoretically-derived curve.
The theoretical curve uses two parameters:
1. The laser beam waist diameter
2. The minimum scattered light intensity required for detection by photodetectors.
Fitting data to theoretical curve retrieves (1), leaving (2) as the only free parameter.
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Comparisons of PDI and Gerber derived LWC.
(A) No roll-off correction applied to Gerber data.
(B) Normal roll-off correction.
(C) Roll-off shifted by 7 um (towards smaller sizes)
(D) PDF of 1 Hz LWC data during MASE.