Hydrological and oceanic effects on polar motion from GRACE and models

[1] Terrestrial water storage (TWS) and ocean bottom pressure (OBP) are major contributors to the observed polar motion excitations, second only to atmospheric mass movement. However, quantitative assessment of the hydrological and oceanic effects on polar motion remains unclear because of the lack of global observations. In this paper, hydrological and oceanic mass excitations to polar motion are investigated using monthly TWS and OBP derived from the Gravity Recovery and Climate Experiment (GRACE) for January 2003 until December 2008. The results from this analysis are compared with hydrological model excitations from the European Center for Medium-Range Weather Forecasts (ECMWF) and oceanic model excitations obtained from the Jet Propulsion Laboratory (JPL) using Estimating the Circulation and Climate of the Ocean (ECCO). Results show that the GRACE-derived OBP and TWS better explain the geodetic residual polar motion excitations for the Px component at the annual period, while the GRACE OBP and ECMWF hydrological angular momentum agree better with the geodetic residuals for the annual Py excitation. GRACE ocean and hydrology excitations better explain the geodetic residuals for the semiannual Py excitation. However, the JPL ECCO and ECMWF models better explain the intraseasonal geodetic residual of polar motion excitation in the Px and Py components. The GRACE data demonstrate much higher intraseasonal variability than either the models or the geodetic observations.

[1]  Walter Munk,et al.  The rotation of the earth , 1960 .

[2]  R. Haubrich,et al.  Meteorological Excitation of the Earth's Wobble , 1975 .

[3]  Raymond Hide,et al.  Atmospheric angular momentum fluctuations, length-of-day changes and polar motion , 1983, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[4]  John M. Wahr,et al.  The effects of the atmosphere and oceans on the Earth's wobble and on the seasonal variations in the length of day — II. Results , 1983 .

[5]  C. Wilson.  Discrete polar motion equations , 1985 .

[6]  R. Rosen,et al.  Causes of rapid motions of the Earth's pole , 1988, Nature.

[7]  B. Chao,et al.  Global surface-water-induced seasonal variations in the earth's rotation and gravitational field , 1988 .

[8]  C. Wilson,et al.  Maximum likelihood estimates of polar motion parameters , 1990 .

[9]  B. Chao,et al.  Atmospheric Excitation of the Earth's Annual Wobble' 1980-1988 , 1991 .

[10]  J. Kuehne,et al.  Terrestrial water storage and polar motion , 1991 .

[11]  J. Dickey,et al.  Earth's Variable Rotation , 1991, Science.

[12]  Monitoring atmospheric winds and pressures for Earth orientation studies , 1993 .

[13]  David E. Smith,et al.  Contributions of Space Geodesy to Geodynamics : Earth Dynamics , 1993 .

[14]  J. Dickey,et al.  The oceanic contribution to the Earth's seasonal angular momentum budget , 1993 .

[15]  Jianli Chen,et al.  Discrete polar motion equations for high frequencies , 1996 .

[16]  M. Furuya,et al.  Quasi-periodic wind signal as a possible excitation , 1996 .

[17]  J. Kuehne,et al.  Estimates of the Chandler wobble frequency and Q , 1996 .

[18]  L. Perelman,et al.  A finite-volume, incompressible Navier Stokes model for studies of the ocean on parallel computers , 1997 .

[19]  D. Stammer,et al.  Oceanic signals in observed motions of the Earth's pole of rotation , 1998, Nature.

[20]  Ichiro Fukumori,et al.  Assimilation of TOPEX/Poseidon altimeter data into a global ocean circulation model: How good are the results? , 1999 .

[21]  B. Chao,et al.  Oceanic angular momentum variability estimated from the Parallel Ocean Climate Model, 1988–1998 , 1999 .

[22]  D. Stammer,et al.  Role of ocean currents and bottom pressure variability on seasonal polar motion , 1999 .

[23]  Richard S. Gross,et al.  the excitation of the Chandler wobble , 2000 .

[24]  C. Wunsch,et al.  Improving ocean angular momentum estimates using a model constrained by data , 2001 .

[25]  I. Fukumori,et al.  Recent Earth Oblateness Variations: Unraveling Climate and Postglacial Rebound Effects , 2002, Science.

[26]  Oceanic excitation of the chandler wobble , 2002 .

[27]  S. Jayne,et al.  A method of inferring changes in deep ocean currents from satellite measurements of time‐variable gravity , 2002 .

[28]  Ahmed H. Ali,et al.  Rapid ocean signals in polar motion and length of day , 2002 .

[29]  Thomas J. Jackson,et al.  Soil moisture retrieval from AMSR-E , 2003, IEEE Trans. Geosci. Remote. Sens..

[30]  Dimitris Menemenlis,et al.  Atmospheric and oceanic excitation of the Earth's wobbles during 1980–2000 , 2003 .

[31]  Dennis P. Lettenmaier,et al.  Tracking Fresh Water from Space , 2003, Science.

[32]  S. Jayne,et al.  Observing ocean heat content using satellite gravity and altimetry , 2003 .

[33]  M. Watkins,et al.  The gravity recovery and climate experiment: Mission overview and early results , 2004 .

[34]  R. Steven Nerem,et al.  Preliminary observations of global ocean mass variations with GRACE , 2004 .

[35]  B. Tapley,et al.  Oceanic effects on polar motion determined from an ocean model and satellite altimetry: 1993-2001 , 2004 .

[36]  Jianli Chen,et al.  Oceanic excitations on polar motion: a cross comparison among models , 2004 .

[37]  Jianli Chen,et al.  Hydrological excitations of polar motion, 1993–2002 , 2005 .

[38]  C. Hughes,et al.  Observing seasonal bottom pressure variability in the North Pacific with GRACE , 2006 .

[39]  Dennis P. Lettenmaier,et al.  Hydrology: Water from on high , 2006, Nature.

[40]  Jianli Chen,et al.  Revised atmospheric excitation function series related to Earth's variable rotation under consideration of surface topography , 2006 .

[41]  J. Famiglietti,et al.  Estimating groundwater storage changes in the Mississippi River basin (USA) using GRACE , 2007 .

[42]  Richard S. Gross,et al.  Earth Rotation Variations – Long Period , 2007 .

[43]  R. Kwok,et al.  Recent trends in Arctic Ocean mass distribution revealed by GRACE , 2007 .

[44]  S. Jayne,et al.  A comparison of in situ bottom pressure array measurements with GRACE estimates in the Kuroshio Extension , 2008 .

[45]  Jens Schröter,et al.  A pattern‐filtering method for the determination of ocean bottom pressure anomalies from GRACE solutions , 2008 .

[46]  J. Willis,et al.  Analysis of large-scale ocean bottom pressure variability in the North Pacific , 2008 .

[47]  Matthew Rodell,et al.  Analysis of terrestrial water storage changes from GRACE and GLDAS , 2008 .

[48]  R. Gross.  An improved empirical model for the effect of long-period ocean tides on polar motion , 2009 .