AIDJEX Bulletin #40 - Polar Science Center - University of Washington

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milestones, kept the vendor working on these problems,which were not resolved fully until well into the main experiment. The performance of the NavSat Data Acquisition Systems in the main experiment was excellent. Position measurements good to about 20 m were obtained throughout the experiment, the longest interruption being about five days at one camp. The data logging function also performed well, with occasional interruptions of only a few days. The oceanographic data have some noise, introduced in the signal processors before the data reached the data acquisition system, which requires filtering in the data processing. This noise was present during the field test, but was removed by careful shielding. Less care was taken in the main experiment. More expensive digitizing hardware might reduce the noise problem, but the data on hand are adequate. The acoustic positioning system was used again during the main experiment to investigate inertial oscillations, and performed as expected. The total expense for positioning systems during AIDJEX was about $600,000. The early decision to develop data buoys that did not dependonan experimental satellite not yet launched presented a major technical challenge. The requirement of several position measurements per day, accurate to about 100 my meant that these would be the first buoys to make extensive use of NavSat. The requirement for data transmission to a central station could only be met by high frequency radio, which increased the power consumption and buoy complexity. Against these demands, redundant measurements of barometric pressure and temperature seemed simple. The cost of 10 such buoys and a central processing facility was estimated to be about $750,000. Since this was more money than was available in the NSF contract for this purpose, outside financial support was needed. The obvious place to go was the NOM Data Buoy Office, and a visit was made in late 1972 to explain the requirements. Subsequent events led to contracts by NDBO for concept definition and development and construction of three buoys, but not in time for field tests of a complete buoy prior to the main experiment. The AIDJEX office contracted for seven additional buoys and for the central station hardware. A considerable amount of testing was necessary on the ice at the beginning of the main experiment. Several refinements in the electronic and physical construction of the buoys were made on the ice under pressure to 3
complete the deployment of the array. Eight of these buoys were in operation by late May 1975 and produced a spectacularly precise picture of ice movement. Unfortunately, the euphoria was short-lived,as half of the buoys quit in midsummer due to what was later found to be corrosion caused by moisture from a still unexplained source. During a brief period in the fall some of the failed buoys were recovered and one of these was put back into service. Four buoys continued to operate with little change through the balance of the experiment. As predicted, communication in the winter months was poor since it had not been possible to achieve reliable transmission of data on the backup HF frequency. One of the two types of barometers employed in each buoy also was affected adversely by the moisture in the summer. As later calibrations revealed, the other type of barometer was unaffected and produced quite good pressures. These shortcomings might have been eliminated had there been time for field tests in the summer of 1974. Though uncertainties concerning the launch of the Nimbus 6 satellite precluded complete dependence on the spacecraft's Random Access Measurement System (RAMS) for buoy tracking and data relay, the relatively low cost of RAMS transceivers made them attractive risks as a backup system for the HF- NavSat buoys. Originally, it was planned to include a RAMS transmitter on each of the HF-NavSat buoys, but a more attractive alternative was offered when Polar Research Laboratory (PRL), with Office of Naval Research support, proposed construction of completely separate buoys using the RANS electronics and the barometers planned for use as backup sensors on the HF-NavSat buoys, and acoustic sensors provided by PRL. With logistic support incidental to the HF-NavSat buoy program, the RAMS buoys were placed adjacent to the larger buoys to provide an additional degree of security against loss or destruction. This arrangement proved to be crucial to the success of the experiment when the HF-NavSat buoy failures occurred. Even though the RAMS buoys had to be deployed prior to the launch of Nimbus 6, eight of ten worked reliably and had marginally adequate position and pressure accuracy. During the experiment about two-thirds of the position data and about half of the pressure data from the main array were obtained from these buoys. The RAMS buoys were refurbished in 1976, and two continued in operation more than two years after original deployment. 4
Page 2 and 3: DATA BUOYS AIDJEX BULLETIN No. 40 J
Page 4 and 5: NOTE TO FRIENDS, AND BYSTANDERS . .
Page 6 and 7: SUMMARY OF TECHNICAL DEVELOPMENTS I
Page 10 and 11: The scene during deployment of HF-N
Page 12 and 13: The initial AIDJEX scientific plan
Page 14 and 15: poizr-orbiting satellite, which is
Page 16 and 17: t@ the spacecraft during each orbit
Page 18 and 19: BUOY NAHE COMMUN. COMMANDS FIXES TA
Page 20 and 21: L( 0 I 2 3 4 3 Radial error, kilome
Page 22 and 23: The buoy will be subjected to tempe
Page 24 and 25: nics occupy about 12 feet of the 17
Page 26 and 27: Ill -- - KEY AIUJEX WIN WW AEBa 0 4
Page 28 and 29: event that a melt pond should form
Page 30 and 31: chute supplied by Paranetics Inc. i
Page 32 and 33: 6'" IqORGANIC LITHIUM BP.TTEI?Y IMP
Page 34 and 35: OM (AD RAMS) UREMEN~ \ AIRDROP N m
Page 36 and 37: provides a grid from which geostrop
Page 38 and 39: words; a four-bit air temperature w
Page 40 and 41: PERFORMANCE OF MET/OCEAN BUOYS IN A
Page 42 and 43: Sensor samples were taken every thr
Page 44 and 45: strengths are known, were used with
Page 46 and 47: the ice (causing reduced shear). An
Page 48 and 49: (McPhee, Mangum, and Martin) , TABL
Page 50 and 51: 70°N 75'N n 3 P 17OOW (D Y 170°W
Page 52 and 53: 12OOW * U Station 25. Xeasurements
Page 54 and 55: (McPhee , Mangum, and Martin) 2701
Page 56 and 57: (McPhee, Mangum, and Martin) a 0 a
Page 58 and 59:
"i BUOY 4 I 43 360- 309- 257 206 15
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a30gl 251 I 60 511 r 43 BUOY 4 I
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n 4, (McPhee, Mangum, and Martin) 8
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(McPhee, Mangum, and Martin) 33 W c
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. '-,..I.. . B A R R O W W I N D S
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:
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I 25 23 t h--:!li[ NCI PiHCEl4l 22
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.5 .4 .3 0 A R 2 R 0 W J - 0 B U -
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9 1.5 1.0 c 8 w .5 R 930 $ 565 1000
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Clock corrections were applied rout
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Q) u o z z i 4- 4- Z + + z f n 9 Ef
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TABLE 1 DIFFERENCES IN DAILY TEMPER
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Laboratory calibration of the ADRAM
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3.20- - 1 t W o? 2 3.051 ...:-.;..
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POSITION MEASUREMENTS OF AIDJEX MAN
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some redundancy. Four points were u
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75.5 75.: - E75.1 LLI % y75.c - 1 1
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The translocation principle removes
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POSITION ACCURACY To evaluate the q
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TABLE 1 STAND-ALONE ACCURACY 68th P
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Az i mu t h s When both receivers a
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DATA PROCESSING Following the field
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model ice motion in the statistical
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FREC 1 INCY / DOPPLER / FREQUENCY /
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35 30 25 v) > 0 2 20 LL 0 r= E m 15
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An example of a large-scale buoy ar
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observations are needed in remote a
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useful for determining how various
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as well as velocity fields, we must
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Since small changes in the yield su
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The transformation of the system of
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e able to judge how well such a mod
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then the flow rule becomes Q = +A -
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[-B' -F Finally, we eliminate Carte
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differential equation. 2. Discontin
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Substituting (36) and (37) into (34
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arbitrarily assign the values of 1
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The special case when advection can
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TABLE 1 STRETCHING, STRESS, ASP CHA
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ate of deformation, we have normali
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CHARACTERISTIC EQUATIONS The ordina
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One way to circumvent the problems
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The equations governing solutions a
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It is readily seen that when body f
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which may be substituted into equat
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a the stress derivative dCldS remai
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Although we have not studied in thi
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Courant, R., and D. Hilbert. 1962.
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A RESEARCH PLAN TO TEST THE AIDJEX
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the barges managed to reach their d
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APPROACH A baseline simulation 0-f
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SENSITIVITY OF ICE RESPONSE TO DIFF
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Since free drift of ice is computed
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and what is observed becomes less i
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stresses appear to be relatively un
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ehavior is directly related to accu
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TABLE 1 COMPARISON OF ESTIMATED ERR
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a) Base line b) 24-hour prediction
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\ / a) Base line b) 24- hour predi
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a) Base line b) 24- hour predi ct i
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\ / a) Base line b) 24-hour predict
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.. a) Base line b) 24- hour predict
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J2 a) Base line b) 24-hour predicti
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) 24-hour prediction c) 36-hour pre
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8 Figure 17. AIDJEX surface pressur
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APPENDIX 1 AIDJEX DATA FILES 1. Pos
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9A. Surface-1 eve1 ai r pressure (d
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19. Surface pressure (Val i dated)
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APPENDIX 2 AIDJEX DATA TRANSFERRED
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I -7-71327GEO A Cards (continued) 7
Page 202:
B Cards (continued) 201
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AIDJEX Bulletin #40 - Polar Science Center - University of Washington

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