TOPAZ Data

July 25, 2016

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Daily Summary:

Monday, July 25: CABOTS IOP2
Day 8 of CABOTS IOP 2 observations. TOPAZ data were taken from 11:12 to 01:12 PDT. The measurements overlapped with 4 missed approaches by the SA Mooney in the early afternoon and evening, and two more missed approaches and a spiral to 3 km after midnight. Very hot with an offical high of 39C (102F) at the airport tower around 1630 PDT. Cloud-free all day, but very hazy in the morning with smoke aloft from the Sobaranes Fire. Mountains totally obscured most of the afternoon. Southeasterly surface winds in the morning, veering to the southwest and becoming much weaker in the afternoon. The CBL remained shallow, with westerly winds up to about 800 m in the late morning and early afternoon, and west-northwesterly in the early evening, and northerly at night. Surface ozone peaked at about 80 ppbv* near 1400 PDT, then decreased slowly to 60 ppbv by 1900 PDT. The lidar found 75-85 ppbv of ozone and very high aerosol in the CBL with a thick region of somewhat lower concentrations and aerosol (aged smoke?)immediately above. The ozone and aerosol in this region diminished between 1900 and 2100 PDT, but increased again during the night. This air was capped by a narrow layer with much lower ozone and aerosol near 2 km. Several irregular layers of high aerosol and ozone (up to 120 ppbv) consistent with fresher smoke from the Sobaranes Fire lay between 2 and 3.5 km, sloping downward to between 2 and 3 km during the night. The Mooney sampled this air flying back to Fresno at 2.5 km.