R/V Ronald H. Brown Daily Summaries

Cruise Day 20040801

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RHB spent Saturday night near the Isles of Shoals conducting an comparison with the DOAS NO3 measurements. The ship changed positions once to get out of a local plume produced by a bonfire on shore. The P-3 flew over the ship three times around 11:00 PM local. The ship moved south shortly after dawn and began a study of the Boston plume. RHB was able to sample the Boston plume at least four times during the day at successively farther distances downwind. The last plume encounter was just south of Portland ME, which was approximately 100km down wind.

There were numerous rain showers in the area and RHB passed through a brief intense shower during the early afternoon. During this period the concentrations of most of the gaseous and aerosol species dropped significantly. However, the ozone concentration rose and the air temperature increased, presumably due to downmixing of more polluted (at least in ozone) air from aloft.

Plans for the night call for RHB to move Southeast to a predetermined location for a P-3 overflight at 9:00 AM on Monday.