TOPAZ Data

August 4, 2016

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Daily Summary:

Thursday, August 4: CABOTS IOP2
Day 18 of CABOTS IOP 2 observations. TOPAZ data were taken from 07:56 to 17:08 PDT. Hot with an offical high of 37C (99F) at the airport met tower. Partly cloudy in the early morning, mid-level clouds with cloud base around 6 km. Cu clouds over the Sierra crest. Hazy. The Sierra Foothills were mostly invisible. South-southeasterly surface winds until 1400 PDT, then veering to the west/northwest. Surface ozone increased throughout the day, reached the high 70s ppbv* around 1500 PDT, and decreased after that. The BL grew to about 700 m AGL and BL ozone concentrations peaked around 85 ppbv. The atmosphere above Visalia was much less impacted by wildfire smoke than the day before. Above the BL, moderate aerosol concentrations extended to 1500 - 2000 m AGL, with a more concentrated, thin aerosol layer at the upper boundary. Two high-ozone layers were observed above the BL in the morning (500 - 1000 m and around 1500 m AGL), containing 80 - 85 ppbv of ozone. The lower of these two layers was entrained into the BL around midday. Ozone concentrations in the layer above the BL stayed around 80 ppbv. Between 2 and 3 km AGL, a layer with relatively low ozone levels (low 50s ppbv) was observed.