2017 WFM

Chemical Processing of Organics within Clouds (CPOC) Pilot Study at Whiteface mountain, NY, Aug 2017

CPOC pilot study was a short intensive field project to investigate the chemical processing of organics within clouds. A high-resolution aerosol mass spectrometer (HR-ToF-AMS) was deployed for the first time via the Sprinter van to target the below-cloud aerosol chemical composition, while cloud water and aerosol measurements were conducted at the summit. Wind-lidar and radiosondes launched from an upwind site provided additional characterization of airflow in the vicinity of the mountain to better understand how the site could be utilized to identify pre- and post-cloud processed aerosols. (More information: https://research.asrc.albany.edu/facstaff/lance/CPOC.html)

Highlighted Results (Zhang et al., Observed below-Cloud and Cloud Interstitial Submicron Aerosol Chemical and Physical Properties at Whiteface Mountain, New York, during August 2017, ACS Earth Space Chem., 2019, https://doi.org/10.1021/acsearthspacechem.9b00117):

The WFM mountain area could be influenced by two plumes with one urban-influenced and one forest-influenced, and the two types of plumes have different aerosol component mass fractions with the forest-influenced one having an organic mass fraction over 85% (Aug. 17, 20, and 23).

During cloud measurements, three cloud layers were identified, with enhanced NO3 concentration at the transition layer. The organic and SO4 mass concentrations were similar for the transition layer and the below-cloud layer, while the aerosol mass and number concentration decreased significantly to only 10% and 52% comparing the in-cloud layer to the transition layer.

The average aerosol mass concentrations of TL and BL were similar and larger than the average aerosol mass concentration of IL. The mass fractions of organics and NH4 were stable over all three cloud layers, while SO4 had the highest mass fraction in the BL layer (18%). NO3 had a greater mass fraction in the IL and TL layers (about 6%) compared to the BL layer (about 2%).