Thursday, June 1
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TOPAZ data were recorded from 7:14 - 20:42 PDT. Seasonal temperatures (34 C max) after trough passage, light winds early, increasing to about 15 m/s around midday, and becoming light again after sunset. Isolated Cu clouds over the nearby mountain ranges, otherwise clear. Ozone increased to the mid 60s ppb after the growing BL had entrained the residual layer. In the late morning, the BL grew rapidly from 700 to 2700 m AGL and clean air above 1.5 km AGL was entrained into the BL, which likely caused the ~10 ppbv drop in ozone concentrations. The strong southerly winds kept the area well ventilated and surface ozone stayed in the low to mid 50s ppbv. The BL rose to about 3.5 km AGL in the late afternoon and entrained part of the persistent ozone layer that had been observed near that altitude for several days. This was likely the cause for the slight increase in ozone around 1700 PDT. A high-ozone layer (~ 100 ppbv) associated with a stratospheric intrusion on the back side of the departing trough was observed above 5 km AGL, well above the top of the BL.