FAST-LVOS 2017 TOPAZ Data

June 30, 2017

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Daily Summary:

Friday, June 30
TOPAZ data were recorded from 09:07 - 21:31 PDT. The final day of FAST-LVOS measurements. High-normal temperatures again today (max. of 42 C at the lidar site) and 106 F at the NLVA NWS tower. Clear skies all day. The winds followed the usual pattern of morning northwesterlies,and week mid-day southwesterlies, but were very light all day, allowing ozone to accumulate near the surface. Thick haze/smoke near the surface in the morning once again. As before, HYSPLIT suggests this haze may have come from fires in northwestern Nevada or Northern California. The elevated UT/LS layer advected from the Pacific Ocean was still present above 5 km asl in the morning, but was thicker and more diffuse with 80-90 ppbv of ozone. Another UT/LS layer with higher concentrations lay above it and a diffuse Asian pollution layer with lower ozone, but higher aerosol still lay beneath it. This lower layer was mostly entrained by the ML, which grew to about 3 km. The surface concentrations at NLVA peaked at 90 ppbv, and the CCDAQ monitors at Joe Neal, Walter Johnson, and Palo Verde recorded MDA8 concentrations in excess of 70 ppbv.