CACHE94: FSSP/PVM/CPC Messages: 31 Entries..

New PVM gain settings: 
 
 The PVM gain settings on the amplifier 
had to be changed due to new 10 hz filter 
board (refer to message under A2D). 
 
 New settings: 
 
channel		gain/offset	cal 
 
102		   1/-		0.0002609252 
 
sensor: GSI, calibration:  LWC =  v * 1.71 
 
105		   1/-		0.002609252 
 
sensor: OSU, calibration:  LWC = v * 1.71 
 
 
cal:  x = (5/32768) * 1.71 
 

PVM.CAL 
 
 
This morning:  PVM hookup (ground level) and test of 3 
signals: 
 
Clear air:  The OSU PVM gave 14 mV.  This is number 28 by 
Herman's accounting, and # 102 by ASTER's.  Herman's PVM 
(#12, ASTER#105) had a clear air signal that varied with 
time (initially 10mV, then later 19mV, still later 28 mV 
all in the morning). 
 
Blocked signal:  both PVM's gave very nearly 0mV for the 
blocked laser (I recall -1mV for the OSU PVM). 
 
Calibration disk:  The OSU PVM consistently gave ~106mV. 
Herman's PVM gave a varied response:  initially it said 
~90mV.  Then it seemed to change up to ~102mV, and finally 
(after warming up, presumably) ~106mV. 
 
 
At about 4pm, both instruments were mounted on the tower 
("flux tower"), OSU @ 10.75 meters, and Herman @ 10 meters. 
 

FSSP.CALIB.MOUNT 
 
 
p.m., FSSP alignment checked (RV), (one bad assembly: suspect  
photodetector mismount), beads blown at FSSP (T. Delaney demo. 
new method of bead supply):  FSSP sizing seems ok but small 
count anomaly persists, FSSP mounted on R.I.B.  
 

FSSP work: 
 
 Playing with fssp.c throughout the day 
to get it running. Made changes to add 
the ability to change range settings. This 
added a channel to the message to signal which 
range the instrument is running in. Peter ran 
his software with a can message to verify operation. 
 

Potential sync problem: 
 
 It has been observed when marigold is 
rebooted that the data stream from the fssp 
is out of sync. If the signal from the fssp 
is disconnected before reboot then reconnected 
after bootup, the data stream looks good. 
Furhter investigation is necessary. 
 

PVMs switched at 10 m. 
 
At 2:30 pm today we switched the vertical position of the two PVMs. 
Now the OSU PVM (blue) is at 10 m. while the GSi PVM (yellow) is at 10.75 m 
Previously these positions were reversed. This is an intercomparison. 
 

CPCs not hooked up: 
 
  The CPCs are not connected. Dave 
Covert believes we are pulling his signals 
down. I have check them and it looks ok to me. 
Rick will get in touch with Dave to decide on 
what to do. 
 

PVM CALIBRATION DISK AND OCCULTATION 
 
 
(August 5, ~ 4:03pm PDT) 
Julian day 217, from 23:03:50 to 23:05:40, calibration procedure 
was applied to the two PVMS.  The procedure is as follows: 
 
1. Block the beam with a hand, for about 5 seconds 
2. Apply the calibration disk for about 5 seconds 
3. Repeat step 1. 
 
Results are in the data file /data/CACHE94/raw_data/flux/fast217181456. 
 
 
 
 
 

PVM CALIB./OCCULTATION/HEIGHT 
 
 
Saturday, August 6 from 17:25:30 to 17:28:30, Pit repeated the 
calibration procedure for the two PVMs (block, disk, block). 
 
Andy followed about 5 minutes later. 
 
 
Rick followed at 18:02:00. 
 
 
All times are GMT 
 
 
21:00:00 (later in the same afternoon):  the GSI PVM was  
hiked up to 15m (-36cm). 
 

FSSP restarted at 17:22 GMT. 
 

pvm.10m.flux moved to 10m.walk at 22:00 gmt. 
 

pvm.15m.flux moved to 10m.flux spot at 1:31 gmt 
 

Height change PVM from 15-m to 10-m 
 
16-aug-94, 1:25Z 
PVM sensor moved down from 15-m to 10-m height. 
Changed cal_files for c.pvm.15m.flux.CACHE (or thereabouts) 
and 10m. to reflect the addition of coefficients on the 
10-m and made 15-m cals go to zero beginning day 228. 
# 
# calibration file for 15m flux PVM sensor during CACHE94 
# 
#Date/Time	gain		offset 
94 212 000000	0.0002609252	0.0 
# Removed sensor from the 15m height on 15-aug-94 
94 228 012500	0.000		0.0 
 
 

PMV calibration disk, Wed 8-17-94 retrospective entry 
between 1530 and 1610 PDT on Wed 8-17-94 the PVM calib disk 
was applied to both PVMs  (OSU on walk, GSI at 10 m. on flux) 
     entered on Fri 8-19 at 10 am from written notes 
 
 
ASK - added note on 8/24: 
 
For this day, the results of the calib./occult. are: 
 
 
OSU:  blocked = 0.1mV, clear = 14.4mV, disk = 109.0 mV 
 
GSI:  blocked = 15.8mV, clear = 50.2mV, disk = 120.8mV 
 

PVM calibration disk, Fri. 8-19-94, during drizzle 
The PVM calib disk was applied at 950 am including occultation 
to the GSI (10 m. flux) and OSU (10 m. walk) models. 
Light drizzle started just prior to GSI calib., increasing to 
light rain prior /during application to OSU PVM on walkup tower. 
 
 
 
ASK note, added 8/24: 
 
 
Results of calib./occult.: 
 
OSU :    the time trace of LWC showed no clear signature of the occultation 
	 calibration procedure.  There's something there (9:50 am), but I 
	 wouldn`t try to interpret it in terms of block/clear/disk 
 
GSI :    blocked 14.6mV, clear 49.1mV, disk 112.9mV 
 

FSSP PVM colocated intercomparison on walkup tower 
Note that the better PVM-FSSP intercomparisons occurred the evenings of 
8-17-94 Wed eve and 8-16-94 Tues eve. Both were long events with 
the Wed eve event having higher LWC (worst intercompare when L > 1.0) 
but the boom was out a bit for Wed until about midnight when winds shifted 
from NNW to W at which time boom was good. 
Tues eve. was analyzed in some detail by R.Vong and Steve Oncley on-site. 
It had west winds and very good LWC intercompare. Note that the OSU PVM 
LWC was NOT corrected (NOT /1.2205 that is). raw correlation at 10 Hz 
was 0.75 to 0.83 within 30 min. periods. FSSP data do not appear to 
correlate with PVM faster than about 0.5 Hz to 2 Hz (somewhere in that range, 
it seems). Activity was typically 28% at 8 am Thurs 8-18 but seemed to 
Peak at 33% during the higher FSSP LWCs (1.2 gm/m3). Therefore be careful 
of activity in parts of this intercomparison 
 

OSU PVM taken down from walkup tower 
The OSU PVM was taken down from walkup tower at noon today Fri 
8-19-94. Brief problem with boomdir indicator but appears Ok now 
 

Forgot to reconnect Solent and FSSP 
 
We needed to disconnect the solent and FSSP when we rebooted marigold 
last night and forgot to reconnect them.  We also had forgotten to 
restart cockpit, so I called Rick and asked him to start cockpit. 
He discovered the problem and reconnected the cables at about 2115 
(local) - 0415 Z?  (while the site was in cloud). 
 
During the reboot the barometer also died.  We have just restarted it. 
 

PVMs subjected to calibration disk: Sat 14:39 to 14:55 
First teh GSI then the OSU PVM were subjected to cal. disk 
Conditions were good, altho RV could not completely see receiving 
'apterature' to insure correct disk placement. 
 

PVMS SET TO GRADIENT CONFIGURATION 
 
 
18:30 - 19:20 (GMT):  PVMs moved from 13m to 10m (OSU) and 15m(GSI) 
for gradient study 
 

GSI PVM Baseline & Optical Cleaning 
 
 
GSI PVM taken down for optical cleaning this morning.  Baseline was 
50mV. 
 
Cleaning yielded the following: 
 
blocked signal ~ 10mV 
clear air      ~ 40mV 
disk           ~ 116mV 
 
A call to H. Gerber (GSI) and we decided *not* to adjust the zero 
potentiometer, since it affects the calibration of the instrument. 
Herman's suggestion was that we should apply the disk frequently 
to examine the change in the output of the GSI PVM.  He indicated 
that the disk could be applied in cloud as well as in clear air, 
but that care should be taken to keep the disk clean (no rain 
or condensation) while being applied. 
 

Calibration for c.pvm.15m.flux changed 
 
At Andy's request, I've modified both prep.config.raw 
and cal_files/c.pvm.15m.flux files to multiply the 
nominal gain (of 1.71) by 1.33 on the 15m pvm. 
 

BELATED ENTRY (8/20): PVM CALIB./OCCULT  
 
(Retyped by ask, RV comment from 8/20 got lost in logbook) 
 
PVMs subjected to calibration disk:  Sat 14:39 to 14:55 
First the GSI then the OSU PVM were subjected to cal. disk 
Conditions were good, altho RV could not completely see receiving 
aperature to insure correct disk placement. 
 

PVM calibration disk and occultation at 13:20 to 13:30 pm
First OSu at 10 m then GSI at 15 m.
Sunday Sept 4 , 1994

PVM results from today:

      baseline   occulted   cal.disk
OSU     .0352      .0003      .1855
GSI     .1140      .034        .2625

cal disk blocked beam    clear air (etc)

East winds but we left the boom to SW. Nppt cloud near top of fog bank/cap cloud.

The Osu 10 m. PVM was removed at 11 am for cleaning. When reinstalled it was bagged to 
prewvent addional rain ingress. Altho the bag was briefly removed (in-cloud) at 1114 (approx time) it was not finally removed until 1537. At that time the clear
air signal was determined to be ~ 14 mvolts.

Paucity of aerosol => large droplets.
Change FSSP range to range=1 (2-47 microns) in order to capture the entire
droplet size distribution.

Effective 23:37 (GMT) to 01:46 (GMT) on day 258

Then back to range 2

From 9:30 a.m. (PDT) to ~11:15 a.m., the GSI PVM was removed from the flux
tower, the collimator lens was cleaned using deionized water (soap seemed 
unnecessary), and the instrument was remounted on the same dog-leg boom as
the OSU PVM for another intercomparison study.

The two PVMs are back-to-back on the same dog-leg boom.  No vertical separation,
and the horizontal separation is ~0.5 meters in the along-boom direction.

Listed below is a summary of all (?) operational changes made to the mounting, 
software, or optical cleaning of the PVMs during CACHE-3.  The PVM with the
blue tape is listed as "OSU"; the orange taped PVM is listed as "GSI".  These
acronyms reflect ownership of the two PVM models.

Date	GMTime		Comment

8/1	2300		PVMs mounted, OSU @ 10.75m, GSI @ 10m, both on flux Tow.
8/4	2130		PVMs swapped, OSU @ 10m, GSI @ 10.75m, both on Flux Tow.
8/6	2100		GSI PVM moved up to 15m on Flux Tower
8/15	2200		OSU PVM moved to 10m Walk T., 1st DiD change
8/16	0131		GSI PVM moved down to 10m.flux, w/ assoc. DiD
8/19	1900?		OSU PVM unmounted from Walk T.
8/19	2355?		Both PVMs moved to 13m on Flux Tower (w/ orig. DiDs)
8/23	1900		OSU set to 10m.flux, GSI set to 15m.flux
8/24	~1900		GSI PVM:  unmount, clean optics, remount @ 15m.flux
8/26	2000		GSI PVM calib. multiplied by 1.33 
9/9	1800-2237	OSU PVM:  unmount, clean optics, remount bagged
9/17	1630-1830	GSI PVM: unmount, clean optics, remount @ 10m.flux

This represents the final configuration, with both PVMs mounted at 10m.flux
(the GSI DiD still saying 15m.flux) on the same boom for intercomparison.

I compiled this list by examining the TKLOG, and the OSU logbooks for CACHE-3.
Some of the times listed are not very firmly known.