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

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SUMMARY OF TECHNICAL DEVELOPMENTS IN AIDJEX Pat Martin AIDJEX Early in the planning for AIDJEX it was recognized that the success of the program depended on the availability of reliable automatic data acquisition and transmission systems (data buoys) and accurate positioning systems. These systems would involve an extension of existing technologies, including adaptation to arctic operating conditions. Since these development tasks were of central importance to the experiment, and were not within the scope of any single research component, responsibility for them was assigned to the project office. As AIDJEX Technical Coordinator, I was responsible for both development efforts. The approach adopted was to contract for the system's engineering development and production, with the project office staff being responsible for stating system requirements, monitoring contractor performance, and deploying and operating the systems. About ten person-years of effort were devoted to these tasks under the AIDJEX office contract with the National Science Foundation. Development efforts for the two systems commenced in 1971 for the 1972 pilot study. The primary positioning system chosen for the pilot study was the Navy Navigation Satellite System, Transit. The necessary equipment was available commercially and was leased because of the short duration of the 1972 program. The problems encountered generally resulted from the use of relatively new equipment in an unusual environment without sufficient redundancy. An acoustic positioning system also was acquired in 1972 to resolve small amplitude (meters), high frequency (hours) ice motion. This system, while built to the specifications of the project, was well within the state of the art and performed as expected. Oscillations of ice motion with a 12-hour period observed by Hunkins on T-3 were found to be inertial rather than tidal with this acoustic positioning system. The other major finding was that there is little "power" at frequencies of ice velocity greater than 2 day-'. 1
Since the 1972 data buoy requirements could not be met with equipment available commercially, it was necessary to contract for the development and production. This effort was carried out in only a few months, and much of the final testing was completed on the ice. This pattern was to repeat itself in the main experiment with unfortunate consequences. Five of six buoys which were deployed measured and recorded hourly values of barometric pressure successfully for more than a month, providing data to drive calcu- lations of geostrophic wind. recovery by radio from overflying aircraft. These buoys were designed to permit data An additional element of the data buoy program in 1972 was the development and deployment of six buoys which also measured pressure and temperature and communicatedthesedata and position information through a NASA meteorological satellite, Nimbus 6. These buoys, with an average life in excess of one year, were developed with NGAY Zudl;ag in response to AIDJFX long-term needs. The experience with iata buoys and positioning systems in 1972 was vital to preparations for the main experiment . Two of the key decisions made in preparing for the 1975-76 main experiment were to contract for Transit systems with additional data logging capability rather than develop them in-house, and to use two data buoy tems, one of which would not depend on NASA experimental satellites to transmit data. The former decision was implemented in the issuance of a request for proposals for NavSat Data Acquisition Systems in late 1973. technical content of the specifications reflected three years of intensive study and experience with Transit. successfully negotiated by the end of 1973. The vendor was selected and a contract adaptation of commercially available equipment and its assembly into systems configured to meet the needs of the experiment. of the contract the company lost several key people, which caused delays in design and construction. postponed about six months until the fall of 1974. sys- These tests were successful in demonstrating most of the system characteristics, including accurate positioning and data logging. However , some problems remained, including an unacceptable temperature sensitivity in the reference oscillators and unfin- ished programing. The contract called for the Shortly after the signing As a result, field tests of the system had to be The level of detail in the contract, together with substantial amounts of money held for progress payments at performance The 2
Page 2 and 3: DATA BUOYS AIDJEX BULLETIN No. 40 J
Page 4 and 5: NOTE TO FRIENDS, AND BYSTANDERS . .
Page 8 and 9: milestones, kept the vendor working
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
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(McPhee, Mangum, and Martin) a 0 a
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"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
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B Cards (continued) 201
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AIDJEX Bulletin #40 - Polar Science Center - University of Washington

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