TOPAZ Data

June 16, 2016

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Daily Summary:

Thursday, June 16: CABOTS IOP1
Day 19 of CABOTS IOP 1 observations. TOPAZ data were taken from 08:42 - 20:50 PDT. Conditions generally similar to previous few days with severe clear. Cooler with a high of 28C. Northwesterly winds in the morning with relatively low aerosol; Sierras visible. Ozone was low from the surface to 2500 m in the morning with very low concentrations near 2300 m. Higher concentrations above with a narrow layer of more 75 ppbv at 3000 m. Aerosol was generally low above the BL with slightly enhanced backscatter between 1200 and 2000 m. Ozone increased slightly near 1000 m and mixed to the surface as the BL grew to about 1500 m near midday. The winds aloft shifted to the northeast in the late afternoon, advecting the smoke plume from the Goliath prescribed burn in Kings Canyon over the lidar near 1500 m and leading to very high backscatter around 1600 PDT. Some smoke mixed to the surface between 1700 and 1800 PDT, but most remained at the top of the BL. Ozone was enhanced in the smoke plume, especially at about 1400 m near the bottom of the plume between 1530 and 1700 PDT. The winds aloft shifted to the north after about 1800 PDT and both the backscatter and ozone decreased. Surface ozone reached a maximum of about 45 ppbv, dropping precipitously around 20:00. There was a strong, pungent odor in the area at that time. An SJVAPCD tech suggested that probably originated at the green waste composting facility on the other side on CA99.