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Polar motion

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explanation for the observed frequency-amplitude behavior would be a forced, but slowly changing quasi-periodic excitation by interannually varying atmospheric dynamics. Indeed, a quasi-14 month period has been found in coupled ocean-atmosphere general circulation models, and a regional 14-month signal in regional
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with m the observed amplitude (in units of mas), and ν the frequency (in units of reciprocal sidereal years) of the Chandler wobble. In order to generate the Chandler wobble, recurring excitation is necessary. Seismic activity, groundwater movement, snow load, or atmospheric interannual dynamics have
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of the order of 100 years. It is a measure of the elastic reaction of the Earth. It is also the explanation for the deviation of the Chandler period from the Euler period. However, rather than dying away, the Chandler wobble, continuously observed for more than 100 years, varies in amplitude and
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simulates dissipation due to the elastic reaction of the Earth's interior. As in Figure 2, the result is the sum of a prograde and a retrograde circular polarized wave. For frequencies ν < 0.9 the retrograde wave can be neglected, and there remains the circular propagating prograde wave where the
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the longitude of maximum pressure. The Hough function in a first approximation is proportional to sin θ cos θ. Such standing wave represents the seasonally varying spatial difference of the Earth's surface pressure. In northern winter, there is a pressure high over the North Atlantic Ocean
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There is now general agreement that the annual component of polar motion is a forced motion excited predominantly by atmospheric dynamics. There exist two external forces to excite polar motion: atmospheric winds, and pressure loading. The main component is pressure forcing, which is a standing wave
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of the annual component of polar motion as function of year. Numbers and tick marks indicate the beginning of each calendar month. The dash-dotted line is in the direction of the major axis. The line in the direction of the minor axis is the location of the excitation function vs. time of year.
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It is improbable that the internal parameters of the Earth responsible for the Chandler wobble would be time dependent on such short time intervals. Moreover, the observed stability of the annual component argues against any hypothesis of a variable Chandler resonance frequency. One possible
297:. The annual component is rather constant in amplitude, and its frequency varies by not more than 1 to 2%. The amplitude of the Chandler wobble, however, varies by a factor of three, and its frequency by up to 7%. Its maximum amplitude during the last 100 years never exceeded 230 mas. 233:
Observations show that the figure axis exhibits an annual wobble forced by surface mass displacement via atmospheric and/or ocean dynamics, while the free nutation is much larger than the Euler period and of the order of 435 to 445 sidereal days. This observed free nutation is called
230:(6,356,752.3 m). Using the geometric axis as the primary axis of a new body-fixed coordinate system, one arrives at the Euler equation of a gyroscope describing the apparent motion of the rotation axis about the geometric axis of the Earth. This is the so-called polar motion. 328:
been suggested as such recurring forces, e.g. Atmospheric excitation seems to be the most likely candidate. Others propose a combination of atmospheric and oceanic processes, with the dominant excitation mechanism being ocean‐bottom pressure fluctuations.
101:. Since about 2000, the pole has found a less extreme drift, which is roughly along the central meridian. This less dramatically westward drift of motion is attributed to the global scale mass transport between the oceans and the continents. 242:
m per year in the direction of 80° west has been observed which is due to mass redistribution within the Earth's interior by continental drift, and/or slow motions within mantle and core which gives rise to changes of the moment of inertia.
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It is difficult to estimate the effect of the ocean, which may slightly increase the value of maximum ground pressure necessary to generate the annual wobble. This ocean effect has been estimated to be of the order of 5–10%.
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cause abrupt polar motion by altering the volume distribution of the Earth's solid mass. These shifts are quite small in magnitude relative to the long-term core/mantle and isostatic rebound components of polar motion.
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To describe such behavior theoretically, one starts with the Euler equation with pressure loading as in eq.(3), however now with a slowly changing frequency ν, and replaces the frequency ν by a complex frequency
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and a pressure low over Siberia with temperature differences of the order of 50°, and vice versa in summer, thus an unbalanced mass distribution on the surface of the Earth. The position of the vector
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The number of the maximum pressure amplitude is tiny, indeed. It clearly indicates the resonance amplification of Chandler wobble in the environment of the Chandler resonance frequency.
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Earth's Rotation from Eons to Days: Proceedings of a Workshop Held at the Centre for Interdisciplinary Research (ZiF) of the University of Bielefeld, FRG. September 26-30, 1988
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would be its geometric axis defined by the geographic north and south pole, and identical with the axis of its polar moment of inertia. The Euler period of free nutation is
332: 132:. In the case of the Earth, it is almost identical with its axis of rotation, with the discrepancy due to shifts of mass on the planet's surface. The vector of the 313:
shows a sometimes rapid frequency shift within a few years. This reciprocal behavior between amplitude and frequency has been described by the empirical formula:
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Kikuchi, I., and I. Naito 1982 Sea surface temperature analysis near the Chandler period, Proceedings of the International Latitude Observatory of Mizusawa,
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The slow drift, about 20 m since 1900, is partly due to motions in the Earth's core and mantle, and partly to the redistribution of water mass as the
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In the range of validity of the empirical formula eq.(2), there is reasonable agreement with eq.(7). From eqs.(2) and (7), one finds the number
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The annual variation was discovered by Karl Friedrich Küstner in 1885 by exact measurements of the variation of the latitude of stars, while
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of a rotating system remains constant and is directed toward a fixed point in space. If the earth were perfectly symmetrical and rigid,
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Gross, Richard S.; Lindqwister, Ulf J. (4 May 1992). "Atmospheric excitation of polar motion during the GIG '91 Measurement Campaign".
951: 238:. There exist, in addition, polar motions with smaller periods of the order of decades. Finally, a secular polar drift of about 0.10 439:
describing the latitude distribution of the atmospheric pressure on the ground, θ the geographic co-latitude, t the time of year, t
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of the annual component describes an ellipse (Figure 2). The calculated ratio between major and minor axis of the ellipse is
73:), being the pole's average location over the year 1900. It consists of three major components: a free oscillation called 978: 807: 712: 139:
of the system (or maximum principal axis, the axis which yields the largest value of moment of inertia) wobbles around
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Jochmann, H., The Earth rotation as a cyclic process and as an indicator within the Earth's interior, Z. geol. Wiss.,
1094: 286: 70: 97:, i.e. the slow rise of land that was formerly burdened with ice sheets or glaciers. The drift is roughly along the 1085:
Eubanks, T.M. (1993). "Variations in the orientation of the earth". In David E. Smith; Donald L. Turcotte (eds.).
290: 1382:, The effects of the atmosphere and oceans on the Earth's wobble — I. Theory, Geophys. Res. J. R. Astr. Soc., 749:"Free polar motion of a triaxial and elastic body in Hamiltonian formalism: Application to the Earth and Mars" 1570:"Polar Motion: A Historical Overview on the Occasion of the Centennial of the International Latitude Service" 77:
with a period of about 435 days, an annual oscillation, and an irregular drift in the direction of the 80th
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Hameed, S.; Currie, R.G. (1989). "Simulation of the 14-month Chandler wobble in a global climatic model".
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This article is about motion relative to the crust. For motion relative to an astronomical framework, see
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Dickey, Jean; Eubanks, T. (July 1985). "Earth Rotation and Polar Motion: Measurements and Implications".
270: 823: 748: 53:. This is measured with respect to a reference frame in which the solid Earth is fixed (a so-called 258: 1049:
Schuh, H (1990). "Earth's rotation measured by VLBI". In Peter Brosche; Jürgen Sündermann (eds.).
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is the polar moment of inertia of the Earth, A is its mean equatorial moment of inertia, and
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is the Chandler resonance frequency. The result is in good agreement with the observations.
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Vondrak, J., Long-periodic behaviour of polar motion between 1900 and 1980, A. Geophys.,
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vector of polar motion moves on a circle in anti-clockwise direction. The magnitude of
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Hide, 1984 Rotation of the atmosphere of the earth and planets, Phil. Trans. R. Soc.,
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Polar motion is defined relative to a conventionally defined reference axis, the CIO (
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relative to the stars with different periods, caused mostly by the torques on the
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Proceedings of the National Academy of Sciences of the United States of America
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Runcorn, S.K., et al., The excitation of the Chandler wobble, Surv. Geophys.,
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due to the gravitational attraction of the Moon and Sun. They are also called
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reference frame). This variation is a few meters on the surface of the Earth.
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This polar motion should not be confused with the changing direction of the
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Guinot, B., The Chandlerian wobble from 1900 to 1970, Astron. Astrophys.,
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found the free nutation in 1891. Both periods superpose, giving rise to a
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The earth's variable rotation : geophysical causes and consequences
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would remain aligned with its axis of symmetry, which would also be its
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amounting to several meters on the surface of the Earth: 100 mas
973:(Digitally printed ed.). Cambridge: Cambridge University Press. 802:(Digitally printed ed.). Cambridge: Cambridge University Press. 722: 308:
that is excited by a source and then dies away with a time constant τ
174:= A/(C − A) sidereal days ≈ 307 sidereal days ≈ 0.84 sidereal years 598:
It is a resonance curve which can be approximated at its flanks by
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Chen, J.L.; Wilson, C.R.; Ries, J.C.; Tapley, B.D. (7 June 2013).
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the normalized frequency of one solar year, λ the longitude, and λ
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is the normalized Euler frequency (in units of reciprocal years),
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of 3.082 m, when converted to radians and multiplied by the
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Contributions of space geodesy to geodynamics: Earth dynamics
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Current and historic polar motion data is available from the
262: 144: 339:. Note in using this data that the convention is to define 58: 1289:
International Earth Rotation and Reference Systems Service
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Gross, R (2001). "The excitation of the Chandler Wobble".
828:
International Earth Rotation and Reference Systems Service
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International Earth Rotation and Reference Systems Service
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The observed angle between the figure axis of the Earth
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Motion of Earth's rotational axis relative to its crust
952:"Quake moved Japan coast 8 feet, shifted Earth's axis" 117:
In the absence of external torques, the vector of the
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Volland, H (1996). "Atmosphere and Earth' Rotation".
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is usually considered a resonance phenomenon, a free
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with a period of about 5 to 8 years (see Figure 1).
207:(mas). This rotation can be interpreted as a linear 38:
as function of time in days (0.1 arcsec ≈ 3 meters).
893:Adhikari, Surendra; Ivins, Erik R. (8 April 2016). 851:"Rapid ice melting drives Earth's pole to the east" 1112:IEEE Transactions on Geoscience and Remote Sensing 971:The Rotation of the Earth A Geophysical Discussion 496:, corresponding to a Chandler resonance period of 81:west, which has lately been less extremely west. 1612: 1089:. Washington, D.C.: American Geophysical Union. 1013: 969:Munk, Walter H.; MacDonald, Gordon J.F. (2009). 488:From Figure 2 together with eq.(4), one obtains 994: 992: 990: 1467:. Cambridge University Press (CUP): 221–236. 1109: 1053:. Springer Berlin Heidelberg. pp. 1–12. 999:Moritz, Helmut; Mueller, Ivan Istvan (1987). 998: 968: 892: 1402: 1291:. Federal Agency for Cartography and Geodesy 1201: 1199: 1197: 987: 830:. Federal Agency for Cartography and Geodesy 1574:International Astronomical Union Colloquium 1461:International Astronomical Union Colloquium 1324:Wahr, J.M. (1988). "The Earth's Rotation". 1580:. Cambridge University Press (CUP): 1–24. 1080: 1078: 888: 886: 507:= 441 sidereal days = 1.20 sidereal years 1593: 1550: 1540: 1499:Earth Rotation and Equatorial Coordinates 1480: 1194: 926: 874: 793: 791: 789: 787: 775: 746: 672:. The observed maximum value of m yields 155:to a good approximation, the figure axis 1517:"Twentieth century sea level: An enigma" 1454: 895:"Climate-driven polar motion: 2003–2015" 373: 29: 1205: 1084: 1075: 883: 797: 269:, except for the slowest, which is the 151:. For a rigid Earth which is an oblate 1613: 1001:Earth rotation: theory and observation 784: 525:the latitude of maximum pressure, and 350:to be positive along 0° longitude and 281:Polar motion is observed routinely by 1248: 1048: 949: 361:to be positive along 90°E longitude. 1567: 1511: 1323: 680:. Together with eq.(8), one obtains 390:on the Earth's surface at the poles) 1346:10.1146/annurev.ea.16.050188.001311 816: 388:100 mas (milliarcseconds) = 3.082 m 369: 13: 1448: 1392:10.1111/j.1365-246X.1982.tb04972.x 1311:"IERS Conventions 2010: Chapter 8" 713:International Polar Motion Service 540: 45:of the Earth is the motion of the 14: 1642: 287:very-long-baseline interferometry 71:Conventional International Origin 190:C − A = 2.61 × 10 kg m 1431: 1396: 1373: 1360: 1317: 1303: 1277: 1242: 1181: 1168: 1155: 1142: 1103: 1042: 950:Voigt, Kevin (April 20, 2011). 276: 1007: 962: 943: 842: 740: 632:The maximum amplitude of m at 1: 733: 1457:"Polar Motion — an Overview" 1455:McCarthy, Dennis D. (2000). 1326:Annu. Rev. Earth Planet. Sci 1016:Geophysical Research Letters 337:Earth orientation parameters 186:C = 8.04 × 10 kg m 112: 7: 1059:10.1007/978-3-642-75587-3_1 701: 324:(for 0.83 < ν < 0.9) 271:precession of the equinoxes 64: 55:Earth-centered, Earth-fixed 10: 1647: 1508:". Retrieved Jun. 5, 2005. 777:10.1051/0004-6361:20041312 544: 15: 1595:10.1017/s0252921100061170 1482:10.1017/s0252921100061364 364: 199:and its angular momentum 84: 1568:Dick, Steven J. (2000). 1285:"Earth orientation data" 1128:10.1109/TGRS.1985.289427 531:= −0.07 years = −25 days 143:. This motion is called 1425:10.1029/gl016i003p00247 768:2005A&A...432.1101F 554:sea surface temperature 426:a pressure amplitude, Θ 295:satellite laser ranging 47:Earth's rotational axis 1542:10.1073/pnas.092704599 1497:Fisher, Rick (1996). " 1114:. GE-23 (4): 373–384. 919:10.1126/sciadv.1501693 798:Lambeck, Kurt (2005). 747:Folgueira, M. (2005). 391: 39: 718:Pole shift hypothesis 377: 259:Earth's rotation axis 33: 22:astronomical nutation 1271:10.1029/2000gl011450 320:m = 3.7/(ν − 0.816) 1586:2000ASPC..208....3D 1533:2002PNAS...99.6550M 1473:2000ASPC..208..223M 1417:1989GeoRL..16..247H 1338:1988AREPS..16..231W 1263:2000GeoRL..27.2329G 1220:1996SGeo...17..101V 1120:1985ITGRS..23..373D 1028:1992GeoRL..19..849G 911:2016SciA....2E1693A 867:2013GeoRL..40.2625C 556:has been observed. 291:lunar laser ranging 91:Greenland ice sheet 1504:2011-08-18 at the 1405:Geophys. Res. Lett 1251:Geophys. Res. Lett 1228:10.1007/bf01904476 855:Geophys. Res. Lett 392: 99:80th meridian west 40: 1527:(10): 6550–6555. 1068:978-3-642-75587-3 1036:10.1029/92GL00935 876:10.1002/grl.50552 861:(11): 2625–2630. 756:Astron. Astrophys 728:True polar wander 595:(for ν < 0.9) 415:(θ) cos cos(λ − λ 213:geographical pole 203:is a few hundred 95:isostatic rebound 1638: 1607: 1597: 1564: 1554: 1544: 1494: 1484: 1442: 1435: 1429: 1428: 1400: 1394: 1377: 1371: 1364: 1358: 1357: 1321: 1315: 1314: 1307: 1301: 1300: 1298: 1296: 1281: 1275: 1274: 1246: 1240: 1239: 1203: 1192: 1185: 1179: 1172: 1166: 1159: 1153: 1146: 1140: 1139: 1107: 1101: 1100: 1082: 1073: 1072: 1046: 1040: 1039: 1011: 1005: 1004: 996: 985: 984: 966: 960: 959: 947: 941: 940: 930: 899:Science Advances 890: 881: 880: 878: 846: 840: 839: 837: 835: 820: 814: 813: 795: 782: 781: 779: 762:(3): 1101–1113. 753: 744: 686: 679: 671: 645: 638: 620: 604: 594: 582: 566: 532: 524: 516: 502: 495: 466: 450: 434: 433: 414: 413: 401: 389: 370:Annual component 360: 349: 323: 319: 285:methods such as 241: 191: 187: 183: 165: 130:axis of rotation 119:angular momentum 49:relative to its 34:Polar motion in 18:axial precession 1646: 1645: 1641: 1640: 1639: 1637: 1636: 1635: 1611: 1610: 1515:(14 May 2002). 1506:Wayback Machine 1451: 1449:Further reading 1446: 1445: 1436: 1432: 1401: 1397: 1378: 1374: 1365: 1361: 1322: 1318: 1313:. p. §8.3. 1309: 1308: 1304: 1294: 1292: 1283: 1282: 1278: 1247: 1243: 1204: 1195: 1186: 1182: 1173: 1169: 1160: 1156: 1147: 1143: 1108: 1104: 1097: 1083: 1076: 1069: 1047: 1043: 1012: 1008: 997: 988: 981: 967: 963: 948: 944: 905:(4): e1501693. 891: 884: 847: 843: 833: 831: 822: 821: 817: 810: 796: 785: 751: 745: 741: 736: 704: 694: 690: 684: 677: 673: 669: 665: 661: 657: 653: 649: 643: 637: 633: 628: 624: 618: 616: 612: 608: 602: 592: 590: 586: 580: 570: 565: 561: 549: 547:Chandler wobble 543: 541:Chandler wobble 530: 526: 522: 518: 514: 510: 506: 500: 493: 489: 484: 478: 474: 470: 464: 454: 448: 444: 442: 432: 429: 428: 427: 425: 418: 412: 409: 408: 407: 405: 399: 387: 380:Rotation vector 372: 367: 359: 351: 348: 340: 321: 317: 311: 302:Chandler wobble 279: 239: 236:Chandler wobble 205:milliarcseconds 189: 185: 181: 177: 173: 169: 163: 115: 87: 75:Chandler wobble 67: 28: 25: 12: 11: 5: 1644: 1634: 1633: 1628: 1623: 1609: 1608: 1565: 1509: 1495: 1450: 1447: 1444: 1443: 1430: 1395: 1372: 1359: 1316: 1302: 1276: 1241: 1193: 1180: 1167: 1154: 1141: 1102: 1095: 1074: 1067: 1041: 1022:(9): 849–852. 1006: 986: 980:978-0521104067 979: 961: 942: 882: 841: 824:"Polar motion" 815: 809:978-0521673303 808: 783: 738: 737: 735: 732: 731: 730: 725: 720: 715: 710: 703: 700: 692: 688: 675: 667: 659: 655: 651: 647: 635: 626: 622: 614: 610: 606: 588: 584: 568: 563: 545:Main article: 542: 539: 528: 520: 512: 504: 491: 482: 476: 472: 468: 452: 446: 443:a time delay, 440: 437:Hough function 430: 423: 416: 410: 403: 371: 368: 366: 363: 355: 344: 309: 278: 275: 252:beat frequency 179: 171: 167: 114: 111: 93:melts, and to 86: 83: 66: 63: 26: 9: 6: 4: 3: 2: 1643: 1632: 1629: 1627: 1624: 1622: 1619: 1618: 1616: 1605: 1601: 1596: 1591: 1587: 1583: 1579: 1575: 1571: 1566: 1562: 1558: 1553: 1548: 1543: 1538: 1534: 1530: 1526: 1522: 1518: 1514: 1510: 1507: 1503: 1500: 1496: 1492: 1488: 1483: 1478: 1474: 1470: 1466: 1462: 1458: 1453: 1452: 1440: 1434: 1426: 1422: 1418: 1414: 1410: 1406: 1399: 1393: 1389: 1385: 1381: 1376: 1369: 1363: 1355: 1351: 1347: 1343: 1339: 1335: 1331: 1327: 1320: 1312: 1306: 1290: 1286: 1280: 1272: 1268: 1264: 1260: 1256: 1252: 1245: 1237: 1233: 1229: 1225: 1221: 1217: 1213: 1209: 1208:Surv. Geophys 1202: 1200: 1198: 1190: 1184: 1177: 1171: 1164: 1158: 1151: 1145: 1137: 1133: 1129: 1125: 1121: 1117: 1113: 1106: 1098: 1096:9781118669723 1092: 1088: 1081: 1079: 1070: 1064: 1060: 1056: 1052: 1045: 1037: 1033: 1029: 1025: 1021: 1017: 1010: 1002: 995: 993: 991: 982: 976: 972: 965: 957: 953: 946: 938: 934: 929: 924: 920: 916: 912: 908: 904: 900: 896: 889: 887: 877: 872: 868: 864: 860: 856: 852: 845: 829: 825: 819: 811: 805: 801: 794: 792: 790: 788: 778: 773: 769: 765: 761: 757: 750: 743: 739: 729: 726: 724: 721: 719: 716: 714: 711: 709: 706: 705: 699: 696: 681: 662: 640: 630: 599: 596: 577: 575: 557: 555: 548: 538: 534: 508: 497: 486: 479: 461: 459: 438: 420: 396: 395:of the form: 384: 381: 376: 362: 358: 354: 347: 343: 338: 334: 329: 325: 314: 307: 303: 298: 296: 292: 288: 284: 283:space geodesy 274: 272: 268: 264: 260: 255: 253: 249: 248:S.C. Chandler 244: 237: 231: 229: 226: 222: 218: 214: 210: 206: 202: 198: 193: 175: 160: 158: 154: 150: 149:free nutation 146: 142: 138: 135: 131: 127: 123: 120: 110: 107: 102: 100: 96: 92: 82: 80: 76: 72: 62: 60: 56: 52: 48: 44: 37: 32: 23: 19: 1577: 1573: 1524: 1520: 1513:Munk, Walter 1464: 1460: 1438: 1433: 1408: 1404: 1398: 1386:, 349, 1982 1383: 1375: 1367: 1362: 1329: 1325: 1319: 1305: 1293:. Retrieved 1288: 1279: 1257:(15): 2329. 1254: 1250: 1244: 1211: 1207: 1188: 1183: 1175: 1170: 1162: 1157: 1149: 1144: 1111: 1105: 1086: 1050: 1044: 1019: 1015: 1009: 1000: 970: 964: 955: 945: 902: 898: 858: 854: 844: 832:. Retrieved 827: 818: 799: 759: 755: 742: 697: 695:≥ 100 years 682: 663: 641: 631: 600: 597: 578: 573: 558: 550: 535: 509: 498: 487: 480: 462: 457: 421: 397: 393: 382: 356: 352: 345: 341: 330: 326: 315: 299: 280: 277:Observations 256: 245: 232: 228:polar radius 209:displacement 200: 196: 194: 176: 161: 156: 140: 136: 125: 121: 116: 103: 88: 68: 54: 43:Polar motion 42: 41: 1370:, 197, 1984 1295:7 September 1178:, 419, 1988 1165:, 351, 1985 834:7 September 621:(for (ν − ν 134:figure axis 106:earthquakes 36:arc-seconds 1626:Astrometry 1621:Precession 1615:Categories 1411:(3): 247. 1380:Wahr, J.M. 1214:(1): 101. 1152:, 07, 1992 734:References 605:m ≈ 14.5 p 583:m = 14.5 p 378:Figure 2. 221:arc length 211:of either 1604:0252-9211 1491:0252-9211 1236:129884741 723:Pole tide 678:≥ 230 mas 670:∼ 0.2 hPa 576:becomes: 567:, where ν 515:= 2.2 hPa 267:nutations 113:Principle 1561:12011419 1502:Archived 1354:54540284 1136:46607194 1003:. Ungar. 937:27152348 702:See also 650:= 14.5 p 639:becomes 306:nutation 217:subtends 153:spheroid 79:meridian 65:Analysis 1631:Geodesy 1582:Bibcode 1529:Bibcode 1469:Bibcode 1413:Bibcode 1334:Bibcode 1332:: 231. 1259:Bibcode 1216:Bibcode 1116:Bibcode 1024:Bibcode 928:4846461 907:Bibcode 863:Bibcode 764:Bibcode 708:Geodesy 613:/|ν − ν 523:= −170° 481:where ν 449:= 1.003 225:Earth's 1602:  1559:  1552:124440 1549:  1489:  1352:  1234:  1134:  1093:  1065:  977:  935:  925:  806:  685:  644:  619:  603:  593:  581:  562:ν + iν 501:  494:= 0.83 465:  422:with p 400:  365:Theory 322:  318:  240:  182:= 1.19 164:  104:Major 85:Causes 1350:S2CID 1232:S2CID 1191:, 107 1132:S2CID 752:(PDF) 691:= 1/ν 634:ν = ν 625:) ≫ ν 402:p = p 263:Geoid 170:= 1/ν 145:Euler 51:crust 1600:ISSN 1557:PMID 1487:ISSN 1441:, 64 1439:21 K 1297:2015 1189:A313 1091:ISBN 1063:ISBN 975:ISBN 933:PMID 836:2015 804:ISBN 683:(9) 642:(8) 601:(7) 579:(6) 499:(5) 463:(4) 398:(3) 316:(2) 300:The 293:and 162:(1) 59:ECEF 20:and 1590:doi 1578:178 1547:PMC 1537:doi 1477:doi 1465:178 1421:doi 1388:doi 1342:doi 1267:doi 1224:doi 1124:doi 1055:doi 1032:doi 956:CNN 923:PMC 915:doi 871:doi 772:doi 760:432 676:max 648:max 475:= ν 335:'s 219:an 147:'s 57:or 1617:: 1598:. 1588:. 1576:. 1572:. 1555:. 1545:. 1535:. 1525:99 1523:. 1519:. 1485:. 1475:. 1463:. 1459:. 1419:. 1409:16 1407:. 1384:70 1368:12 1348:. 1340:. 1330:16 1328:. 1287:. 1265:. 1255:27 1253:. 1230:. 1222:. 1212:17 1210:. 1196:^ 1150:19 1130:. 1122:. 1077:^ 1061:. 1030:. 1020:19 1018:. 989:^ 954:. 931:. 921:. 913:. 901:. 897:. 885:^ 869:. 859:40 857:. 853:. 826:. 786:^ 770:. 758:. 754:. 658:/ν 629:) 617:| 591:/ 533:. 517:, 471:/m 435:a 431:−3 419:) 411:−3 289:, 273:. 192:. 1606:. 1592:: 1584:: 1563:. 1539:: 1531:: 1493:. 1479:: 1471:: 1427:. 1423:: 1415:: 1390:: 1356:. 1344:: 1336:: 1299:. 1273:. 1269:: 1261:: 1238:. 1226:: 1218:: 1176:9 1163:3 1138:. 1126:: 1118:: 1099:. 1071:. 1057:: 1038:. 1034:: 1026:: 983:. 958:. 939:. 917:: 909:: 903:2 879:. 873:: 865:: 838:. 812:. 780:. 774:: 766:: 693:D 689:D 687:τ 674:m 668:0 666:p 660:D 656:C 654:ν 652:0 646:m 636:C 627:D 623:C 615:C 611:C 609:ν 607:0 589:C 587:ν 585:0 574:m 569:D 564:D 529:0 527:t 521:0 519:λ 513:0 511:p 505:C 503:τ 492:C 490:ν 483:C 477:C 473:2 469:1 467:m 458:m 453:0 447:A 445:ν 441:0 424:0 417:0 406:Θ 404:0 386:( 383:m 357:y 353:p 346:x 342:p 310:D 201:M 197:F 180:E 178:ν 172:E 168:E 166:τ 157:F 141:M 137:F 126:M 122:M 24:.

Index

axial precession
astronomical nutation

arc-seconds
Earth's rotational axis
crust
ECEF
Conventional International Origin
Chandler wobble
meridian
Greenland ice sheet
isostatic rebound
80th meridian west
earthquakes
angular momentum
axis of rotation
figure axis
Euler
free nutation
spheroid
milliarcseconds
displacement
geographical pole
subtends
arc length
Earth's
polar radius
Chandler wobble
S.C. Chandler
beat frequency

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