From rsf_postmaster Thu Apr 27 13:13:08 1995
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Subject: VORTEX Report #3
To: all_rsf, all_rdp, dcarlson (David Carlson), carbone@mmm.ucar.edu
Date: Thu, 27 Apr 1995 13:12:54 -0600 (MDT)
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Hi, Everyone:

Sorry about this late report for week 4/20/95-4/26/95. I went to Miami to 
present a paper in the Tropical and Hurricane conference. I returned to
Norman Wednesday at noon. The weather in VORTEX region was kind of inactive
for the past week. Temperatures are in the 30s and 40s most of the time. 
Most of us do not have WINTER clothing with us. We were wonder if we are doing
STORM-FEST, not VORTEX. 

Tomorrow and Saturday look good for possible missions. Next Tuesday looks very
promising and next Thurday looks even better (if you trust the model results
that far advance). 

Wen-Chau

                        VORTEX ELDORA REPORT  4/20/95 - 4/26/95

	After Wednesday's excitement of flying through supercells, the cold
front wiped out most of the low level moisture and left us with cold and
dry air in the VORTEX region. There was no VORTEX operations. Craig and Tim
worked on the fore HPA and the problem was fixed. The Translator software
(the front end software for processing ELDORA data) had some problems. Dick
was working on that all day Thursday. Due to single recording on the real-time
system, Bob was busy creating a backup copy of the data tape. Bob and I also
experimented on options to create movies on site (U. of OK) in the correct
orientation. 

	On Friday morning, the moist air was located on near the Gulf
of Mexico. With only slight chance of reaching northern TX by the afternoon.
However, the dry line in the western TX could initiate some convections
in the afternoon. VORTEX was in standby mode until 1pm. The mission was
canceled by 1pm. Translator problem was resolved in the afternoon. I started
to run navigation correction program but encountered Fortran compiler problems.
Thank to Michele Case, she promptly resolved the compiler problems for me
remotely on late Friday afternoon. Bob recreated the movie loop for Monday's
flight and put it in the ATD Mosaic home page. Please check it out. We only
included data from the fore radar to save disk space.

	Saturday was declared a down day for Electra. Data crews were in
data center working. I successfully obtained the correction factors for
navigation and radar pointing angle for the 4/17/95 mission. Every parameter
is normal except for the rotation angle (or roll) corrections. I need to 
correct 1 degree for fore radar and -1 degree for the aft radar in order to
make the data look leveled. I have never encountered this before. It took 
me 3 days to convince myself that this is actually happening. This is likely
to be a radar mounting error or problems in the encoder. As you can tell, we
don't know the reason as this moment.

	A test flight was flown Sunday afternoon to test 1) radio communication
between Electra to P3 (scientist to scientist), 2) GPS drop out problem on
Electra (possible interference with ELDORA?). This was a one hour mission.
It turned out that radio was not working properly and the GPS still does not
work. During the flight, I also noticed that ELDORA did not see much clear
air return. The side lobes hit the ground dominated the display within 10
km range. Roger Wakimoto reexamined the data collected during the first flight
that afternoon and found very good clear return. The dry line can be clearly
seen on both reflectivity and velocity display. I think the detectability of
clear air return is good in warm moist air where bugs were most likely present
than in the cold dry air situation that we encountered on Sunday. Susan
Stringer arrived Sunday afternoon.

	Monday was a down day.

	A test flight was flown Tuesday after noon to test the communication
but it still did not work properly. The real-time ELDORA tape recording 
problem was identified. Occasionally, the buffer is full and crashing the
data system. Craig decided to dump all contents in the buffer (about 3 scans
worth of data) when that occurred in order to keep the data system running. 
Other options will be experimented on Wednesday.

	A cold front was expected to passed through OKC on Wednesday afternoon.
However, the low level moisture was not expected to return in time for any
serious convections. VORTEX was on standby for a 3 pm takeoff. The mission
was canceled at 3 pm. Cold front passed through Norman around 4 pm. When we
drove by to the hotel, a squall line was developed southeast of Norman. Some
rotation was reported within some storms but no tornado was reported. We 
re-examined the dry line radar data on 4/17/95. A quick dual-Doppler analysis
was performed and the results will be examined.