010912 Ron Brown Radar and Sounding Operations Summary

We arrived on station at 10N, 95W early this am.  The radar operated 
continuously without significant problems.  We've discovered on 
several occasions that the antenna migrates up to the vertical stops 
after completing an RHI sequence.  When this happens, the antenna has 
to be brought down using the antenna utility (e.g., solar cal) in 
order to start the next scan.  Not sure what is causing this problem 
although a combination of heavy seas (large pitch) and significant 
counter weights on the antenna may have something to do with it. 
We've tried implementing a dummy surveillance scan after the 
completion of the RHI's in order to get the antenna down; however, 
the results have been mixed.  Not implementing RHI's seems to solve 
the problem, at least temporarily.  Several other error messages have 
cropped up in IRIS; however, as far as we can tell none of them have 
had a deleterious effect on data collection or data quality.  We're 
still looking into the cause of the error messages.  A solar 
calibration was taken around 21:30 UTC - the approximate maximum 
error in elevation pointing angle is 0.4 deg (varies slightly with 
azimuth) and the azimuth error is within 0.1 deg.  Accurate power 
measurements have been recorded for our different scan strategies and 
these have been input into the IRIS software.  "rphase" processing is 
currently being used for all scan strategies but we are still 
tweaking the SQI and CSR thresholds in order to get maximum benefit 
from the  processing technique.

A total of 5 upper air sondes were released today (00, 06, 12, 16, 20 
UTC).  The 00 and 06 UTC were released prior to our arrival at 10N. 
The sonde at 00Z topped out near 270 mb and the 16Z sonde topped out 
near 190 mb.  All other sondes collected data to at least 150 mb. 
The 12Z sonde missed most of the winds below 500 mb.  We are now on a 
6x/day launch schedule.

Weather echos generally decreased throughout the day as a dry layer 
near 2.5 km built in.