| INSTRUMENT MENTOR MONTHLY SUMMARY REPORT |
|---|
Return to a list of available AOS summariesIMMSNo 3390 loaded
| Source: AOS | Report Date: 07/2009 |
Instrument Mentor Monthly Summary Report for AOS: 07/2009
1. Data Review:
During July the aerosol loading was relatively throughout the month with aerosol scattering coefficients ranging from 5 to 100 Mm-1 at 550 nm for the month. The Angstrom exponents for the sub 10 micron aerosol for the 550/700 nm pair ranged between 0.5 and 2.2, with large aerosol on days 190-196. The single scattering albedo (SSA) at 500 nm varied between 0.82 and 0.95. The aerosol hygroscopic growth ranged between 1.4 and 1.5.
2. Instrument Performance Issues and Trends:
All instruments performed relatively well. A nafion dryer was installed on the PSAP sample inlet, which greatly reduced the signal noise. All the instruments were cleaned and calibrated. The nephs were insulated to enhance low RH values in the humidity scans. The vacuum lines were replumbed to pull flow for the excess flow lines through the stack blower. This reduced the number of carbon vane pumps by 2. In the last week of July I noticed a slow decline in the CCN signal despite normal operating parameters for the instruments flows, pressures, %SS set points, laser current, etc. I had the tech remove and clean the capillary tube on the sample inlet as I suspected the inlet line was clogged. There was no improvement in the signal. This particular CCN came from AMF and had spent several years in extreme aerosol loading conditions in Niger and China. Although this instrument just returned from DMT for a new laser and calibrations, I suspect they didn’t clean the interior or sample lines. I’ve asked the tech to return the instrument to Boulder for cleaning and recalibration.
3. Current Task Status:
Repair CCN
4. Near-Term Plans:
Travel to NSA to perform cleaning, calibration of NSA AOS system and reinstall fRH measurements at this site.
5. Accomplishments:
Arthur Sedlacek and Stephen Springston from BNL as well as Brad Orr from ANL were at SGP during my site visit from July 6-10. We talked for two days on the AOS design features and strategies for building both mobile and stationary facilities. The time spent and learning from all was very productive. We plan to keep in close communication as the AMF2 and Darwin AOS systems develop. I anticipate that new design features from the AMF2 AOS can be used in the SGP and AMF AOS.