FAST-LVOS 2017 TOPAZ Data
June 9, 2017
Friday, June 9
TOPAZ data were recorded from 9:50 - 18:54 PDT. Cooler today with a max of 95 F at the NLVA (VGT) NWS station. Mostly clear with widely dispersed contrails. Strong SW to SSW winds greater than 20 m/s with gusts exceeding 25 m/s swept away locally produced O3 and created a wind-driven dust cloud over the Strip. The surface O3 concentrations were about 40 ppbv in the morning, and the remnants of the Pacific streamer were present when TOPAZ measurements commenced at 10 PDT. The first lidar measurements showed more than 100 ppbv of O3 between 2.5 and 3 km agl, but the streamer was highly fragmented with much lower concentrations during most of the day. A modest amount of entrainment and mixing occurred after 1300 PDT, but the surface concentratons remained below 55 ppbv, and only one of the CCDAQ monitors (Mesquite) reached 60 ppbv for the MDA8. As noted before, a combination of aged UT/LS air and transported biomass burning or pollution sources is suspected. Despite the location of the streamer near the elevation of Angel Peak, only traces of UT/LS air were detected there.
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