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Published byVictor Shields Modified over 9 years ago
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-integral to VOCALS objectives -we want to do the best we can: * marine stratus over ocean is the idealization many retrievals of warm cloud properties are based on * VOCALS an opportunity to both nail down retrievals & use “retrieval-breakdowns” to better understand cloud/aerosol/precip behavior * unique characteristic/opportunity for VOCALS Remote sensing of south east Pacific stratus Paquita Zuidema, RSMAS/U of Miami Reading, Sept.,2008 Topics: 1.Liquid water paths 2.Drizzle 3.Satellite-shipboard comparisons (if interest)
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Used cloud volume extinction coefficients constructed from cloud radar+microwave as input into SHDOM
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6 ~month-long cruises to the southeast Pacific since 2001 epic includes a week at 20S, 85W each cruise TMI SST Shipboard instruments : ceilometer (CT-25K) Surface radiative & turbulent fluxes Cloud radar Wind profiler (if Ron Brown) Lasair-II aerosol counter (but not EPIC) Rawindsondes Microwave Radiometer(s)
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During EPIC, LWPs used to assess models and construct further microphysical retrievals
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cc rere NdNd Factor of -1 in slope, as expected from theory 110 < LWP <121 g m -2 121 < LWP <133 g m -2 133 < LWP <146 g m -2 Pt Reyes, CA ARM data N CCN Aerosol scatteringAerosol index McComiskey and Feingold 2007 LWPs useful for quantifying aerosol indirect effects PMS Lasair-II particle counter compares well to a TAMU DMA (but we haven’t been able to characterize the Twomey AIE)
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More modern gaseous/liquid absorption models produce lower LWPs that compare better to adiabatic values
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But they remain noisy…. Current NOAA radiometers have an approximate accuracy of 30 g m -2 at 10-minute resolution Zuidema et al. 2005 Okay for diurnal composite, statistical evaluations adiabatic LWP retrieved LWP Local time adiabatic LWP retrieved LWP For aerosol-cloud-precip evaluations at the eddy scale & r e retrievals, would prefer higher accuracy
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For VOCALS-Rex: Liquid water path measurements 1. C-130 Andrew Pazmany’s 183 GHz MWR upward-pointing (NSF) 2. Ron Brown: non-NOAA 2-channel MWR + ARM Radiometrics 183 GHz MWR (technically not supported, personal loan + ARM instrument request w/ Dr. Maria Cadeddu)
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Cimini et al. 2007
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183-GHz radiometer wing lines still sensitive to liquid water and not saturated by SEP water vapor for an instrument noise level of 0.2 K @ 200 ms (Pazmany,2006), a LWP uncertainty of ~ 2 g m -2 all else - WVP - assumed constant 14 7 Using an EPIC sounding
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Using epic soundings, Physical retrieval + neural net both find 10 g m -2 clear-sky LWP error for individual measurements, 4 g m -2 bias relative to simulated LWPs Excludes instrument calibration issues, but Radiometrics183 Ghz performed well in Barrow. => Have some confidence in ship-based measurements
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C-130 will lack a 20 Ghz MWR with which to separately retrieve water vapor, however. 183 Ghz wing line measurements not enough information for both water vapor and liquid water path retrievals What to do? -assume water vapor field more homogeneous than LWP ? -use ship-based data to assess wvp variability? -even if LWPs not absolutely known, their variability can be? -can be bounded by adiabatically-determined LWPs?
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Overflights of the Ron Brown by the C-130 valuable comparison opportunities In addition am hoping for one high-altitude climb by the C130 for a good cold-space-calibration brightness temperature reading.
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SEP region remarkably drizzly: what is the relationship to LWP, aerosol, mesoscale organization? day night Leon, Wang & Liu, 2008 Note that in SEP region much drizzle evaporates before reaching the surface, changing traditional views on the role of drizzle
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A depth-dependent boundary lapse rate that accounts for boundary layer decoupling was empirically deduced from radiosondes and applied to develop a MODIS cloud top height estimate
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modis ship modis ship Aerosol Cloud depth current work: assess synoptic influence on cloud droplet number concentration builds on Brenguier and collaborators type of ACE analysis
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Suggestions, thoughts ?
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NOAA Lidar: Epic radar+ lidar Lidar could provide insight into mesoscale organization Janet Intrieri
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-integral to VOCALS objectives -we want to do the best we can: * marine stratus over ocean is the idealization many retrievals of warm cloud properties are based on * VOCALS an opportunity to both nail down retrievals & use “retrieval-breakdowns” to better understand cloud/aerosol/precip behavior * unique characteristic/opportunity for VOCALS Remote sensing of south east Pacific stratus Paquita Zuidema, RSMAS/U of Miami Reading, Sept.,2008 Topics: 1.Liquid water paths 2.Drizzle 3.Satellite-shipboard comparisons (if interest)
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