OASIS98: HYGRO Messages: 27 Entries..

I happened to notice that the "MR" on two days: Jul310000-JUl310730cdt
and Jul312000-Aug010900, that the MR from OKMN1.5 and OKMN9.0 are much lower
than the rest. This happened when the wind direction was north easterly (~50)
Any other direction and the "MR" blends in with the rest.

Speed may also be an issue. More observation may be needed. It may be just
me making trouble.

Friday afternoon we tried some serious testing of the intake tubes on the trh
sensors. We put a source of smoke close to the sides of the intake and all
around in different configurations. The general conclusion was that in calm 
conditions that there is very little air being drawn from around the tube.
Most if not all of it came from a column below the tube to about 2 inches
below if that. With wind this column decreases. 

Certainly this warrants a more controlled study as cheap cigars are not good
smoke reference instruments.


The testing did alter temperature measurements at the .5m level from 1400 to 1500. or so.

July 29, Wednesday 17:30 CDT

Installed new MegaTurbo fan on TRH tower.
Moved 0.5m back down from pointing SE at 1.5m
to original 0.5 level underneath the 1.5m trh.

Levels w/ blower aspiration: 0.5, 1.5, 4.5, 9m
Level w/PAM config. Micronel fan: 6.5m

Gut feel observation is that the amount of aspiration on these
4 sensors is about the same as what the smaller blower was doing
for just the 1.5 and 9m.

July 28 12:30CDT
	Moved 1.5m trh to 9m and 9m back to 1.5m
	These new locations were what was the original configuration
	before we swapped them on 7/22 because of apparent offsets.
	Profile technique fluxes for these dropped noticably and since
	we also added improved ventillation at that time we want to
	determine how much of a factor just swapping the trh's was.

T.0.5m

13:25Z, 08:25CDT	Removed Gortex Filter
		Raised T.0.5.m to physical height of 1.5m
		Purpose: Our TRH sensors have been reporting warm with
		respect to the OUMN passive gill shields.  Turbo ventillation
		of the NCAR trh at 1.5 and 9 shows that increase aspiration
		is required for the trh in this orientation.
		We removed the filter to determine whether that will improve
		the performance of the standard sensor configuration with
		micronel DC fan.

19:00Z, 14:00 CDT	Reinstalled Gortex Filter

	Results: Initial results appear to suggest that removing the filter
		did not make a difference.

Weather: hot, sunny, SE winds varying 2-4ms.

We turned off the turbo pump about 14:50, re-erected the T/RH tower, and
turned the pump on about 15:05.  The 4.5m is still using the fan aspiration
whereas the other levels are all on the pump.  It appears that the pumped
sensors are now cooler than the fan, though the 9m is higher than the
others.  I would guess that it isn't getting enough flow through all the
tubing.  (Even though Tony has connected the pump tube half-way up the tower
just to minimize this problem.)

The results of the "laid-down" test (the tower laying flat on the ground)
were inconclusive, since the natural aspiration was good at all levels
with south winds.

22:00Z	Removed forced ventillation on 0.5m and 6.5m trh and reinstalled DCfan.
	Now only 1.5m and 9m have forced vent.
	Purpose: examination of data w/forced vent on 0.5,1.5,6.5 and9
	revealed that the aspiration was still insufficient and the
	OUMN passive gill shields in the ~4ms winds were still better.
	Result: Initial examination via xstrip indicates that the additional
	aspiration on 1.5 and 9 has improved both the response time and the
	absolute values.

We dropped the T/RH tower at about 10:00 and have just completed plumbing
an aspiration system.  About 12:05, we turned the turbo fan on, and it 
appears to be pulling a fair amount of air through at least the bottom
sensors.  We now have it lying almost flat (as of 12:23 it is completely
horizontal), with the T/RH at 4.5m still using the old fan.   We will
run this as a comparison while we are at lunch, and re-erect the tower early
this afternoon.  We probably will leave the 4.5m unit the old way for
another day or two for comparison.

ALSO, we swapped the 9m and 1.5m units.  We did this since we have seen
different errors (presumably radiation) between at these two levels and
it isn't clear to me how this could be radiation.  Granted, we have now
made two changes, and it might be difficult to separate them, but 
if this configuration works better, it won't matter!

We ran the vacuum cleaner from 9:00 to 10:40 CDT today on T/RH 1.5m.
We are going to take a tour of OK, and don't trust running it while we
are gone.
We plan to stop back this evening to check on things.

A persistant +ve difference has been seen for the aspirated NCAR T when compared
to the OKMN natural flow T. NCAR T > OKMN T.
One interpretation is that the NCAR system has insufficient aspiration.
An attempt to drastically increase the NCAR aspiration flow was made.

At 16:35 CDT the trailer vacuum cleaner was arranged to draw air from the 
exhaust pipe of the NCAR 1.5m TRH sensor. A high flow of air was drawn
through across the sensor elements.
At 18:10 removed the vacuum cleaner connection to the exhaust.

We spent this afternoon modifying all the T/RHs to point downwards, since
we've seen more evidence of radiation errors in the NE winds (see today's
daily status.)  We moved the mounts up 34 cm, to keep the inlets at the
same height as before.  For a short time, the 6.5m read bad data, since I
hadn't seated a connector properly.  Everything should now be fine.

All this was done from about 2:00 to 4:00 CDT.

The T/RH at 1.5m was dead again this morning, having died at ~06:05 UTC.

I decided to swap the HC11 boards with the spare we have.  Of course,
it also was necessary to swap the coefficients.  Before the swap, I saved 
the coefficients as:
$ASTER/projects/OASIS98/doc/trh1.doc & trh3.doc.

Then, I reprogramed TRH003 with the coefficients from TRH001 (using COFL).
NOTE: I DID NOT CHANGE THE SERIAL NUMBERS, SO THE SERIAL NUMBERS ARE OF
THE HC11 AND NOT THE SENSOR.

I loaded sensor #1's coefficients into CPU #3
I pulled the old sensor with CPU #1 from the tower.
I swapped brains in the trailer.
I reinstalled the sensor with CPU #3.
I loaded sensor #3's coefficients back into CPU #1 (the spare), just to be
safe.

Thus, CPU #3 should be debugged in the lab, if possible.

The TRH at 1.5m died at 07:54 GMT last night.  We have no idea why.

rserial didn't respond to wake it up; however the fan was running when 
we went out to check on it (therefore it had power).
Cycling power brought it back to life.

(What good is COP if it allows this to happen?)

I've just played with the last 3 days of data and find that the ordering of
the RH profiles is improved if 0.6% is added to RH.4.5m and 0.1% is
subtracted from RH.6.5m and 0.2 is added to RH.1.5m.

Also, the T profile is slightly better by subtracting 0.04C from T.6.5m.

Comparisons indicated that the 6.5m TRH was generating questionable T
At 10:45 CDT the inplace TRH was removed from the tower and the new TRH
brought from NCAR on 3 July was installed.
This sensor did not report RH. It was removed and on inspection it was 
discovered to have a bad board connector. This was fixed and the new TRH
reistalled on the tower at 6.5m at 11:25 CDT

At 13:35 CDT changed s/n to 006

  The 1.5m HYGRO died last night. It appears to be the
same problem with the chip socket for the HC11. I did
a little more work on the contact between pin 21 and
the socket connector. The sensor was deployed at 9:20 local.

We measured the heights of the 1.5m hygrothermometers and 2m props:

NCAR	before	after
T/RH	1.55m	1.50m
prop	2.06m	1.98m

OKMN
'fast' T	1.51m (center of beehive)
cup		2.01m

Adjusted the heights of the NCAR sensors as in 'after' above

  The 1.5m TRH is back on the tower. I hope I have
found the problem. Using the scope I was able to trace
down an intermittent contact between the transmit pin, #21,
on the 68HC11 chip and the socket. I pulled the chip out
and played around with the socket contact. It appears the
chip seats too deep in the socket. Pads were added to the bottom
of the chip. In addition, I did not seat the chip completely
down. If the sensor is alive after 48 hours then I believe the
source of the problem has been found.

  The 1.5m TRH is still stopping after 24 to 48 hour
operation. The problem appears to be a open contact in
the transmit line. After failing in the field the sensor
is brought back into the trailer and tested. after about 1/2
to 1 hour the sensor fails. In the failed mode, I have tried to
remove the electronics. Moving the board out about 1" gets the
sensor running again. It does not go thru a reset. It just starts
sending data out again. This is why I believe it is an open
circuit somewhere. We may need to reseat the processor and 
rom chips. I will wait until we get the chip pullers.
  I have tried soldering points on the board where the transmit
signal would flow. This has not solved the problem. The interface
connector block between the sensor board and the serial cable has been
replaced.

  The HYGROTHERMOMETER has been instrumented. All systems
are go!

Mounted radiation shield intakes pointing nominally south.
Changed the order of the sensors as follows:

Old channel/ht	S/N	New channel/ht
--------------------------------------
200/0.5m	001	201/1.5m
201/1.5m	002	200/0.5m
202/4.5m	003	203/6.5m
203/6.5m	004	204/9.0m
204/9.0m	005	202/4.5m

Steve reoriented the hygrothermometer intakes relative to their
electronics enclosure, in preparation for mounting them on the
tower.  They are now pointing to the SE.

Read/set hygrothermometer serial numbers:

Break-out box	Height	S/N
---------------------------
0		0.5m	001
1		1.5m	002
2		4.5m	003
3		6.5m	004
4		9m	005

At about 10:15 CDT, I replaced goretex filters on the hygrothermometers

The 0.5m, 1.5m, 4.5m hygrothermometers have the filter holders with
4 large slots.  The 6.5m and 9m hygrothermometers have the filter holders
with 8 smaller slots.

On June 19, around 1300 CDT, we transferred the hygrothermometer
intercomparison from the radiation sawhorse to a horizontal tower
section supported by two ladders.  This is located about 15m north
of the hygrothermometer tower, oriented E/W.  The hygrothermometers
are at a height of 1.5m, pointing to the south.

With the radiation shield intakes pointing upwind (south) rather than 
downwind (north), the differences between the temperatures have been 
reduced from a range of about 0.2 C to a range of about 0.1 C.

At 17:15 CDT, removed the gortex shields from the hygrothermometer
50Ys to determine the effect on the temperature intercomparison.

Also noted that the 50Ys had the following PRTs

0.5m	slow
1.5m	fast
4.5m	fast
6.5m	slow
9m	slow

where "slow" is the original Vaisala PRT and "fast" is a faster
response PRT used to replace the Vaisala PRT on several 50Y sensors
prior to Flatland96.

9:12 CDT, June 21

Comparing last night's data to the previous night indicates no
significant effect of running without the filters

0.5m hygrothermometer quit again about 0400 GMT last night.  Steve
removed to work with it on the bench.

08:43 CDT:

4.5m hygrothermometer has been reading 1.5 C too low.  Steve removed it for 
check-out on bench

0.5m hygrothermometer quit last night.  Steve swapped 0.5m and 4.5m cables
at the sensors, so that 0.5m sensor is now coming in on 4.5m channel.

0.5m still not working; Steve removed it for check-out on bench

09:45 CDT:

Stev fixed 4.5m hygrothermometer; temperature coefficient A1 was incorrect;
changed it from a nominal 100 to 102.42268.  Reinstalled on 4.5m channel.

Set up 5 hygrothermometers this morning at same level on radiation sawhorse;
at a height of about 2m; intakes pointing north. 

Sawhorse is oriented roughly E/W and is located near base of hygrothermometer
tower.