From email@example.com Wed Jul 17 11:15:49 1996 Date: Wed, 10 Jul 1996 14:58:55 -0600 (MDT) From: "Herman C. Sievering"
To: ACE-1 Community SUMMARY STATEMENT: CAPE GRIM AEROSOL CHEMICAL CHARACTERIZATION WORKING GROUP Co-chairs: Herman Sievering and Ann Middlebrook Our tasks are: Task A) Compile aerosol chem. data, incl. gas phase species info. of significance to aerosol chem. char. A tentative list of instrumentation/data which applies to this task is given below( Please comment/correct): SIZE-DISTRIBUTED BULK AEROSOL DATA 1) Moudi impactors' data - U. of Hawaii( Huebert & Howell) version obtained from the 10-m stack( ~30-40m asl) under low RH( 35-40 %) conditions. CSIRO( Ayers & Cainey) version obtained from roof( ~30-40m asl) at 30 C or < 50 % RH. 2) Sierra hivol impactor data - U. of Colorado( Sievering & Slavich) obtained from 50m tower level( ~125m asl) under ambient RH( 76 +- 6 % during ACE-1 sampling) conditions. 3) "Gold Top" >1 um and <1 um dia. data - CSIRO( Ivey and Ayers) obtained from roof under ambient conditions. 4) Filter pack >1 um dia. and <1 um data - Bureau of Meteorology( Dick) obtained from base( ground level) of 10 cm dia. stainless steel tube w. inlet at 53-m tower level under ambient RH conditions. SIZE-DISTRIBUTED INDIVIDUAL PARTICLE DATA 5) Laser Mass Spectrometry( PALMS) data - NOAA-Aeronomy Lab( Murphy/Middlebrook/Thomson) Particles of >0.16 um dia. obtained from the 53-m inlet( ~130 m asl) at 60 +- 20 % RH( slightly lower than ambient). 6) Electron Microscopy( EM) analysis of EM grids( 4 size range grids per sample) along with Nucleopore filters under ambient RH conditions. EM grids will be analyzed at Arizona St. Univ.( Posfai & Anderson) by TEM and electron diffraction; filters by SEM. Samples obtained from 50-m level on tower. HYGROSCOPIC GROWTH/LIGHT SCATTERING 7) Tandem Differential Mobility Analyzer( TDMA) data( Covert, U. of Washington) obtained from the 10-m stack at varying RH. Dat will be analyzed to infer chemical composition. 8) Nephelometer data( Rood & Carrico, U. of Illinois) obtained from the 10-m stack at 22%, 40%, and 82% RH with 1um and 10 um dia. cuts. Data will be analzed to infer chemical properties of aerosol. AEROSOL MASS 9) Moudi impactor data( Howell, U. of Hawaii). Mass obtained under low RH conditions from the 10-m stack. GAS PHASE SPECIES 10) Ammonia data( Whung, NOAA-AOML) obtained from ground level next to CG station. Task B) - Identify consistencies/inconsistencies in the data. 1) determine intercomparison species, times, etc. A prime time period is the 2nd ship intercomp. period when winds were favorable. This period began on AM of J338 and continued thru J340. Sea salt mode at CG appears to have varied by factor of 3, or more, at CG during this period w. widely varying RH also. 2) Use scatter plots as first step in comparisons. 3) Cainey/Ayers are unsure of the validity of nssSO4 data from roof/stack for 2 um dia. and larger aerosol. They are reviewing their MOUDI data to ascertain all of the reasons why but local bluff sea spray/soil input is a candidate reason. Task C - Characterize aerosol chem. from viewpoint of met conditions/special events. 1) Baseline periods, 2nd ship intercomp., etc.( Ideas welcome) 2) Smmarize chem. char. of aerosols for each period. Please send comments to HSIEVERI@CARBON.CUDENVER.EDU or AMIDDLEBROOK@AL.NOAA.GOV