Friday, May 19
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TOPAZ data were taken from 10:39 - 18:23 PDT. Still below normal temperatures, light winds. The high-ozone layer (75 - 95 ppbv, 4 - 6  km AGL) aloft persisted and thinned over the course of the day. Surface and BL ozone did not vary much during the day and stayed below 60 ppbv.