Thursday, May 25
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TOPAZ data were taken from 08:03 - 17:55 PDT. Warm temperatures with a high around 36 C, light winds from the early morning hours until midday, followed by an increase in wind speeds to about 20 m/s. Moderate ozone in the residual layer aloft was entrained into the growing BL around 10:30 PDT, resulting in an increase in surface ozone to about 65 ppbv. The very strong winds in the afternoon and evening diluted ozone concentrations, causing surface ozone to stay in the 50s ppbv during the remainder of the day. A high-ozone layer (70 - 85 ppbv) was observed above 4 km AGL after 11:00 PDT.