uncertainties and limitations of the fcdp measurements during attrex 2011
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Uncertainties and Limitations of the FCDP measurements during ATTREX 2011. Sara Lance Presented at the ATTREX Science Meeting Boulder, CO 11-12 June 2012. FCDP – Fast Cloud Droplet Probe. Counts individual particles according to scattering signal - PowerPoint PPT PresentationTRANSCRIPT
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Uncertainties and Limitations of the FCDP measurements
during ATTREX 2011
Sara Lance
Presented at the ATTREX Science Meeting
Boulder, CO11-12 June 2012
![Page 2: Uncertainties and Limitations of the FCDP measurements during ATTREX 2011](https://reader035.vdocuments.net/reader035/viewer/2022062305/5681634c550346895dd3e1b1/html5/thumbnails/2.jpg)
FCDP – Fast Cloud Droplet Probe• Counts individual particles according to scattering signal
– Slightly Larger sample volume during ATTREX for better counting statistics in sub-visible cirrus
• Sizes particles using pulse height analysis. Less precise for ice particles, due to– Variable refractive index– Non-spherical shape
• Ability to count small ice particles– Shattering of large ice particles will artificially enhance the
concentration– Do our best to account for that, shattering removal algorithm– We verify this by comparing to other in-situ observations
(FFSSP and 2D-S)
• Aerosol contribution to measured concentrations is minimal
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Fast-CDP
Knife edge tips to reduce artifacts cause by large ice particles shattering
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Statistical Sampling of Ice Particles by the FCDP
• Ice concentrations typically much lower than cloud drop concentrations
• Options for improving sampling statistics– Use a larger sample area – Average over longer time period (longer distance)
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Concentrations observed during ATTREX
5-6 Nov 2011 Flight
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Concentrations observed during ATTREX
5-6 Nov 2011 Flight
![Page 7: Uncertainties and Limitations of the FCDP measurements during ATTREX 2011](https://reader035.vdocuments.net/reader035/viewer/2022062305/5681634c550346895dd3e1b1/html5/thumbnails/7.jpg)
Concentrations observed during ATTREX
9-10 Nov 2011 Flight
![Page 8: Uncertainties and Limitations of the FCDP measurements during ATTREX 2011](https://reader035.vdocuments.net/reader035/viewer/2022062305/5681634c550346895dd3e1b1/html5/thumbnails/8.jpg)
Concentrations observed during ATTREX
9-10 Nov 2011 Flight
![Page 9: Uncertainties and Limitations of the FCDP measurements during ATTREX 2011](https://reader035.vdocuments.net/reader035/viewer/2022062305/5681634c550346895dd3e1b1/html5/thumbnails/9.jpg)
FCDP observations of small ice particles during LEAR Test Flight
Altostratus, Winter Park, CO2 Sept 2011
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FCDP observations of small ice particles during LEAR Test Flight
Altostratus, Winter Park, CO2 Sept 2011
2DS HVPS
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FCDP observations of small ice particles during LEAR Test Flight
Altostratus, Winter Park, CO2 Sept 2011
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Inverse relationship between NFCDP and Sice observed during ATTREX 2011
5-6 Nov 2011 25.00-25.16 UT
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Hawkeye, ATTREX 2013
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Hawkeye, ATTREX 2013