Aerosol Working Group Location: Room 2.16, 2 nd Floor, Williamson Building, Oxford Road, Manchester 11:00 Coffee 11:30 – 13:00Instrument Updates: CCN/CPC/PSAPJamie Trembath AMS/SMPSWill Morgan LTI/VACCMark Bart SP2Paul Williams Rosemount InletsJamie Trembath PCASPPhil Rosenberg NephsKate Turnbull CASBen Johnson CVI Nominee LIDARFranco Marenco Cardington InstrumentsSimon Osbourne 13:00 – 13:30Lunch 13:30 – 14:30Future Projects, instrumentation requirements, work to be done: FENNECJim MacQuaid SAMBABen Johnson 14:30 – 16:00Working group recommendations, upcoming work/direction, further discussions: Coarse Mode Planned Rack Mods Aircraft CFD analysis

Rosemount Inlet Characterisation experiment - RICEx Instrument Calibrations: PCASP Calibrated prior to flight, Grimm calibration has not been worked up. Grimm not fothcoming with instrument response for the bin boundaries. Instrument co-located comparison: Grimm and PCASP on shared sample of ambient lab air and PSL beads. Data ‘Re-Binned’ with boundaries of 0.25, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 3.0 to allow direct comparison of the instrument two data sets.

B560 – 07/12/2010 RICEx Flight Flight tracked around the coast of Norfolk to the South Coast, multiple straight and level runs at 10 kft, 2 kft and 100 ft. Two inlets were tested at three flow rates. On off valves on inlets so they could be switched in flight Schematic of rack layouts for flights Key Assumption PCASP Representative Flight track overlaid on model output of total aerosol loadings.

Rosemount Inlet Characterisation experiment - RICEx The AMS rack mounted SMPS and the CCN rack mounted Grimm sampled through the aft Rosemount pair, sub samplers were used to modify the flow at the inlet. No transport loss corrections have been applied to this data set. Enhancement drops with flow rate – inertial loss The lower the pressure the lower the enhancement factor for equally sized particles.

Rosemount Inlet Characterisation experiment - RICEx Future work: Correct for transport losses, calibrate Grimm bin boundaries, compare Rosemount inlet directly LTI during FENNEC project using two Grimms. Publish? Data compares well with Petzold 2010: CCN InletAMS Inlet Size Range (μm)This studyPetzold – – – – 3.02 – 78 (166)

CCN Instrument CCN working well, data processed up to RONOCO. Data availability/quality/quantity at ccncpcflightlogdb ccncpcflightlogdb Data already collected appears to be of a good quality. New analyses being tested for VOCALS data, estimation of Kappa, the hygroscospicity parameter from SEP marine boundary layer.

CCN Instrument Comparison: Kappa analysis: VariableThis studyRoberts 2010 κ0.28 (0.3)0.21 (2.0) D s (nm)130 (44)85 (18) fCCN/CN0.42 (0.31)0.26 (0.21) Greg Robert’s work from the northern pacific marine boundary layer.

CCN Closure Modelled CCN data assuming composition of (NH 4 )2SO 4 and Ds as estimated from the Kappa analysis. Model over estimates CCN as κ for (NH 4 )2SO 4 is 0.6, three times greater than the κ estimated. Reasons – nrOMF, Inlet discrepancies, instrument errors

CPC Instrument CPC not working well – EPROM is currently fried. No flights have yet been missed. The instrument should be online again for FENNEC Pilot at the latest. The data is currently processed up to RONOCO. Data availability/quality/quantity at ccncpcflightlogdb ccncpcflightlogdb Data already collected appears to be of a good quality. Large intercomparison undertaken August 2010 at NPL with the following instruments: Institute/instrumentSerial Number UoM CCN FAAM CCN FAAM UoM UoM UoM NPL

CPC Instrument Output from a CAST aerosol generator UoM 3786 over reads FAAM 3786, this was due to a low flow. NPL 3775 has issues in photometric mode, measurements above 10,000 particles cm -3 UoM CCN and FAAM CCN were operated at max. supersaturation (approx 1.5%) using (NH 4 )2SO 4 aerosol the instruments should act as CN counters. This proved correct, opening up the possibilities of calibrating the dual column without a CPC.

PSAP Instrument PSAP has not been flown for some time, as it requires an operator. A MFC good to 20 kft is to be fitted in April 2011 to allow operation on all flights. In preparation the instrument was leak tested in September 2010, it leaked like a sieve. The internal plumbing was all replaced and the optics block cleaned and all were leaks isolated and plugged. Kate is going to talk later about the corrections that should be applied to data in the future.