A little warmer day, mostly sunny during the morning followed by increasing clouds.  Mostly southerly winds with a few dust devils around, later with a few isolated and small rain showers in the distance.

Today started off with good conditions for the campaign, although during the afternoon the increasing clouds were less favorable.  After some checks on the systems, Sam accompanied Jacquie on some soil sampling for ISFS, then worked on the ISS1 PurpleAir aerosol sensor (one of the laser sensors had reduced power so PurpleAir sent a replacement).  The sensor was reinstalled and restarted around 18 UTC, and seems to be working fine.  We checked on the second PurpleAir, out on the ISFS tower array, which has connectivity issues.  I've sent an email to the vendor with some diagnostic info and suspect there may be a network port issue since we are connecting to that one via a DSM Wifi.

I did some work on data backups and then on the lidars. Shane and I looked at some comparisons between the Halo lidars and the REAL lidar.  There is some correlation, particularly between the Metek Halo (staring out towards the ISFS tower array) and the REAL.  For example in the photo below. there are bursts of backscatter in the REAL images drifting towards the northeast, corresponding to plumes in the Halo images Doppler shifted away from the lidars. 

The Metek Halo range is a little limited, today reaching only around 1 to 1.5 km (staring out to the ISFS array).  Briefly interrupted sampling for some checks around 23:45 UTC.  From around 0100 UTC (Aug 15) the averaging time was increased from one second to two seconds, and that does seem to help (eg, lidar.ISS1_halo.202308150120.screenshot_metek.jpg - the change is about halfway along the plot).  The range appeared to increase from around 1500m to almost 2km.  It does mean that the time axes now cover around 35 minutes instead of the previous 17 minutes.  Note that the averaging is unchanged on the vertically pointing UVA Halo lidar, and those plots cover around 10 minutes.

The wind profilers continue to perform well.   This afternoon the 449 MHz profiler was drawing around 2.94A in winds mode and 4.91 A in RASS mode, while the 915 MHz profiler was drawing around 2.44 A.


Example of plumes of backscatter seen in both REAL lidar images (left) and the Metek HALO lidar (right).


Repairing and reinstalling the PurpleAir aerosol sensor on the ISS1 tower