Deceleration in the Earth's oblateness

For over three decades, satellite laser ranging (SLR) has recorded the global nature of the long‐wavelength mass change within the Earth system. Analysis of the most recent time series of 30 day SLR‐based estimates of Earth's dynamical oblateness, characterized by the gravitational degree‐2 zonal spherical harmonic J2, indicates that the long‐term variation of J2 appears to be more quadratic than linear in nature. The superposition of a quadratic and an 18.6 year variation leads to the “unknown decadal variation” reported by Cheng and Tapley (2004). Although the primary trend is expected to be linear due to global isostatic adjustment, there is an evident deceleration ( J¨2=18±1×10−13/yr2 ) in the rate of the decrease in J2 during the last few decades, likely due to changes in the rate of the global mass redistribution from melting of the glaciers and ice sheets as well as mass changes in the atmosphere and ocean.

[1]  P. Melchior,et al.  The Earth's variable rotation, geophysical causes and consequences , 1981 .

[2]  W. Peltier.  Constraint on deep mantle viscosity from Lageos acceleration data , 1983, Nature.

[3]  J. G. Williams,et al.  Secular variation of Earth's gravitational harmonic J2 coefficient from Lageos and nontidal acceleration of Earth rotation , 1983, Nature.

[4]  B. Chao,et al.  Snow load effect on the Earth's rotation and gravitational field, 1979–1985 , 1987 .

[5]  B. Chao,et al.  Effect of a uniform sea-level change on the Earth's rotation and gravitational field , 1988 .

[6]  C. Shum,et al.  Temporal variations in low degree zonal harmonics from Starlette orbit analysis , 1989 .

[7]  N. K. Pavlis,et al.  Temporal variations of the Earth's gravitational field from satellite laser ranging to LAGEOS , 1993 .

[8]  B. Chao.  Anthropogenic impact on global geodynamics due to reservoir water impoundment , 1995 .

[9]  L. V. Morrison,et al.  Long-term fluctuations in the Earth’s rotation: 700 BC to AD 1990 , 1995, Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences.

[10]  E. Ivins,et al.  Global geodetic signatures of the Antarctic Ice Sheet , 1997 .

[11]  Byron D. Tapley,et al.  Determination of long-term changes in the Earth's gravity field from satellite laser ranging observations , 1997 .

[12]  F. Bryan,et al.  Time variability of the Earth's gravity field: Hydrological and oceanic effects and their possible detection using GRACE , 1998 .

[13]  Byron D. Tapley,et al.  Seasonal variations in low degree zonal harmonics of the Earth's gravity field from satellite laser ranging observations , 1999 .

[14]  B. Chao,et al.  The Gravitational Signature of Earthquakes , 2001 .

[15]  Chris Rizos,et al.  An approach to GPS analysis incorporating wavelet decomposition , 2001 .

[16]  Jürgen Sündermann,et al.  Consideration of ocean tides in an OGCM and impacts on subseasonal to decadal polar motion excitation , 2001 .

[17]  Michael R Pearlman,et al.  THE INTERNATIONAL LASER RANGING SERVICE , 2007 .

[18]  B. Chao,et al.  Detection of a Large-Scale Mass Redistribution in the Terrestrial System Since 1998 , 2002, Science.

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

[20]  Anny Cazenave,et al.  Redistributing Earth's Mass , 2002, Science.

[21]  Shailen D. Desai,et al.  Observing the pole tide with satellite altimetry , 2002 .

[22]  P. Döll,et al.  A global hydrological model for deriving water availability indicators: model tuning and validation , 2003 .

[23]  M. Cheng,et al.  Variations in the Earth's oblateness during the past 28 years , 2004 .

[24]  Huug van den Dool,et al.  Climate Prediction Center global monthly soil moisture data set at 0.5 resolution for 1948 to present , 2004 .

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

[26]  M. Watkins,et al.  GRACE Measurements of Mass Variability in the Earth System , 2004, Science.

[27]  Jeffrey P. Walker,et al.  THE GLOBAL LAND DATA ASSIMILATION SYSTEM , 2004 .

[28]  Isabella Velicogna,et al.  Greenland mass balance from GRACE , 2005 .

[29]  O. Francis,et al.  Modelling the global ocean tides: modern insights from FES2004 , 2006 .

[30]  J. Wahr,et al.  Measurements of Time-Variable Gravity Show Mass Loss in Antarctica , 2006, Science.

[31]  Archie Paulson,et al.  FAST TRACK PAPER: Inference of mantle viscosity from GRACE and relative sea level data , 2007 .

[32]  S. P. Anderson,et al.  Glaciers Dominate Eustatic Sea-Level Rise in the 21st Century , 2007, Science.

[33]  B. Ghezali,et al.  Wavelet application to the time series analysis of DORIS station coordinates , 2009 .

[34]  Byron D. Tapley,et al.  Accelerated Antarctic ice loss from satellite gravity measurements , 2009 .

[35]  Low-frequency exchange of mass between ocean basins , 2009 .

[36]  I. Velicogna.  Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE , 2009 .

[37]  Petra Döll,et al.  Global-scale modeling of glacier mass balances for water resources assessments: Glacier mass changes between 1948 and 2006 , 2010 .

[38]  Chung-Yen Kuo,et al.  Global Sea Level Rise: Recent Progress and Challenges for the Decade to Come , 2010 .

[39]  Mark F. Meier,et al.  GLACIERS AND THE CHANGING EARTH SYSTEM: A 2004 SNAPSHOT , 2010 .

[40]  Michael B. Heflin,et al.  Simultaneous estimation of global present-day water transport and glacial isostatic adjustment , 2010 .

[41]  W. Peltier,et al.  GRACE era secular trends in Earth rotation parameters: A global scale impact of the global warming process? , 2011 .

[42]  R. Nerem,et al.  Recent changes in the Earth's oblateness driven by Greenland and Antarctic ice mass loss , 2011 .

[43]  Eric Rignot,et al.  Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise , 2011 .

[44]  Minkang Cheng,et al.  Variations of the Earth's figure axis from satellite laser ranging and GRACE , 2011 .

[45]  Hilton Miami Downtown.  Ocean Surface Topography Science Team Meeting , 2012 .

[46]  W. Tad Pfeffer,et al.  Recent contributions of glaciers and ice caps to sea level rise , 2012, Nature.

[47]  R. Koster,et al.  Assimilation of GRACE terrestrial water storage into a land surface model: Evaluation and potential value for drought monitoring in western and central Europe , 2012 .

[48]  N. K. Pavlis,et al.  The development and evaluation of the Earth Gravitational Model 2008 (EGM2008) , 2012 .

[49]  Sofiane Khelifa,et al.  Analysis of position time series of GPS-DORIS co-located stations , 2013, Int. J. Appl. Earth Obs. Geoinformation.