- 16: SONIC/none Tue 11-Jul-1995 20:39:24 GMT PAM #3 and #1 Sonic orientation, level and calibration
PAM #3 (ISS or Snake Creek Bridge Site)
Yesterday, this sonic was moved up from 3m to 5m.
Since the local vegetation is about 2m high, the
sonic is now about 3m above the vegetation.
Sonic zeroed at 27 deg C, 89 %RH
Sonic V axis oriented at 141 deg 12' 52"
Sonic levels: alev=31 counts, blev=23 counts, (2048=5 deg)
PAM#1 (Brumley Rd)
Sonic zeroed at 30 degC, 69 %RH
Signal amplitude is 0.2 V for first wave, 3.5 V for second wave
Sonic V axix oriented at 127 deg 51', 35"
Sonic levels: alev= -001, blev= -033
- 42: SONIC/none Sat 22-Jul-1995 13:48:11 GMT Removing despiker from EVE
By looking at the sonic raw data, Matt noticed yesterday that the sonic
temperature is indeed spiking more noticeably than the other channels.
This is consistent with the statement by Kaimal that temperature spikes
are larger than wind spikes because sonic temerature is proportional to
the *square* of the sum of the reciprocal transit times, whereas the
velocities are proportional to the *first power* of the difference of
the reciprocal transit times.
However, Matt also noticed that the despiker was replacing good data
with bad data, apparently because the statistics were becoming corrupted
by bad data. This may have occurred because of a sharp change in
turbulence associated with a rain shower or by the onset of the
sea breeze. Although the predicted wind values were realistic, the
temperature data were not even realistic (-2.34e04). This is probably
the explanation of the loss of sonic temperature at all three sites
on the afternoon of July 20, following onset of the sea breeze.
As a consequence, Matt is today going the remove the despiking software
from the serial processing of the sonic data. It will still be used in
a parallel fashion to detect spikes (as best it can), but without
replacing the data.
- 93: SONIC/none Mon 07-Aug-1995 14:45:28 GMT Sonic levels on PAM 2 back
It appears our visit to station 2 the other day got the
levels working again. I would not consider the data good until
we have had a chance to check the sensors.
- 124: SONIC/none Sun 13-Aug-1995 12:43:56 GMT GOES noise test on sonics
The v and u components on sonics at station 2 and 3
are still noisy with the GOES communicaiton turned off.
The GOES wil be turned back on.