FAST-LVOS 2017 TOPAZ Data

June 7, 2017

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Daily Summary:

Wednesday, June 7
TOPAZ data were recorded from 9:52 - 22:24 PDT. Another hot day with a max of 101 F at the nearby (500 m) NLVA (VGT) NWS station. Hazy with widely dispersed contrail cirrus all day. The winds were from the S and SE for most of the day before rotating to the SSW around 1500 PDT. Windspeeds between 5 and 10 m/s prevented the accumulation of locally produced ozone. A layer of high ozone was present just above 2 km when the measurements commenced in the morning, with the bottom of the layer rising to 3.5 km agl by the late afternoon. The concentrations at 3 km agl exceeded 100 pbv from 1400 to 1600 PDT, when some of the ozone was entrained by the mixed layer, causing the surface concentrations to rapidly increase from 65 to 75 ppbv. The TOPAZ in situ concentrations remained above 70 ppbv until about 2000 PDT, causing the MDA8 to reach about 68 ppbv. The MDA8 at 5 of the CCDAQ monitors reached 65 ppbv, and the monitor at Death Valley NP, 150 km WNW of Joe Neal and 120 km W of AP, reached 70 ppbv. High ozone was also measured at Angel Peak. The measurements there indicate that the composition of the elevated layer was complex. There was no visible smoke, but the aerosol backscatter was somewhat enhanced. The O3 at Angel Peak was sometimes correlated with NOy and CO, but not at other times. It was usually correlated with CH4, however. Stratospheric and (AZ?) fire contributions are suspected.