A little cooler today, still mostly sunny with some scattered cloud, very hazy. Sundowner winds are still forecast with a front tomorrow, however the IOP has been delayed a day and is now proposed for Tuesday and Wednesday.
We mostly took a break today, although I did spend a few hours this morning at ISS1 mainly working on the lidar. I rechecked the pointing by scanning the nearby cell phone tower. That showed a peak at around 221.4 - 221.5 deg, very close to the Google Earth estimated orientation os 221.56 deg. I also experimented with the lowest viewing angles by doing PPI scans at 0, 2, 3, and 5 deg. There are lots of trees to the north and east, but there are some narrow gaps so I'm trying to determine the precise angles of those in order to choose the optimal azimuths for the RHI scans. After various tests I selected 18 deg azimuth for the North-South RHI scan, and 95 deg for the East-West scan, not quite orthogonal but this gives the best views between the trees.
The sequence of lidar scans are a vertical stare for 5 minutes to get good statistics on the vertical motion and to get boundary layer depth estimates, followed by a PPI scan at 35 deg for VAD winds and turbulence (1.5 minutes), followed by the North-South RHI azimuth 18 deg and the East-West RHI at azimuth 95 deg (both also 1.5 minutes). The full sequence takes approximately 10 minutes. All scans are at 50 meters resolution.
Views across the top of the lidar head to the north and east showing the gaps in the trees that were selected to provide the lowest RHI scans in each direction.