The Antarctic ice sheet is the largest block of ice on Earth, a tiny change of its ice sheet will have a significant impact on sea level change, so it plays an important role in global climate change. The Gravity Reco...The Antarctic ice sheet is the largest block of ice on Earth, a tiny change of its ice sheet will have a significant impact on sea level change, so it plays an important role in global climate change. The Gravity Recovery and Climate Experiment （GRACE） mission, launched in 2002, provides an alternative method to monitor the Antarctic ice mass variation. The latest Release Level 05 （ RL05 ） version of GRACE time-variable gravity （TVG） data, derived from GRACE observations with improved quality and time-span over 10 years, were released by three GRACE data centers （CSR, JPL and GFZ） in April 2012, which gives us a chance to re-estimate the ice mass change over Antarctic more accurately. In this paper, we examine ice mass changes in regional scale, including Antarctic Peninsula （AP, West Antarctica）, Amundsen Sea Embayment （ASE, West Antarctica）, Lambert-Amery System （LAS, East Antarctica） and 27 drainage basins based on three data sets. The AP mass change rates are -12.03±0.74 Gt/a （CSR, 2004-2012）, -13.92±2.33 Gt/a （JPL, 2004 -2012） , -12.28±0.76 Gt/a （GFZ, 2005-2012） , with an acceleration of -1.50±0.25 Gt/a^2, -1.54±0.26 Gt/a^2, -0. 46±0.28 Gt/a^2 respectively, the ASE mass change rates are -89.22±1.93 Gt/a, -86.28± 2.20 Gt/a, -83.67±1.76 Gt/a with an acceleration of -10. 03±0. 65 Gt/a^2, -8.74±0. 74 Gt/a^2 and -5.69 ±0.68 Gt/a^2, and the LAS mass ehange rates are -4.31±1.95 Gt/a, -7.29±2. 84 Gt/a, 1.20±1.35 Gt/a with an acceleration of -0. 18±0.62 Gt/a^2, 3.55±0.95 Gt/a^2 and 0.97±0.49 Gt/a^2. The mass change rates derived from the three RL05 data are very close to each other both in AP and ASE with the uncertainties much smaller than the change rates, and mass losses are significantly accelerated since 2007 in AP and 2006 in ASE, respectively. However, the mass change rates are significantly different in LAS, negative rate from CSR and JPL data, but positive rate from GFZ data, the uncertainties are even larger than the correspondent change rates. With regard to the 27 drainage basins, seven basins （basin 3-9） located in the east Antarctica show positive mass change rates, and the rest twenty basins are characterized by negative mass change rates during the time span of the three RL05 data.展开更多
基金mainly sponsored by National key Basic Research Program of China(973 Program:2012CB957703)Natural Science Foundation of China(41274035)
文摘The Antarctic ice sheet is the largest block of ice on Earth, a tiny change of its ice sheet will have a significant impact on sea level change, so it plays an important role in global climate change. The Gravity Recovery and Climate Experiment （GRACE） mission, launched in 2002, provides an alternative method to monitor the Antarctic ice mass variation. The latest Release Level 05 （ RL05 ） version of GRACE time-variable gravity （TVG） data, derived from GRACE observations with improved quality and time-span over 10 years, were released by three GRACE data centers （CSR, JPL and GFZ） in April 2012, which gives us a chance to re-estimate the ice mass change over Antarctic more accurately. In this paper, we examine ice mass changes in regional scale, including Antarctic Peninsula （AP, West Antarctica）, Amundsen Sea Embayment （ASE, West Antarctica）, Lambert-Amery System （LAS, East Antarctica） and 27 drainage basins based on three data sets. The AP mass change rates are -12.03±0.74 Gt/a （CSR, 2004-2012）, -13.92±2.33 Gt/a （JPL, 2004 -2012） , -12.28±0.76 Gt/a （GFZ, 2005-2012） , with an acceleration of -1.50±0.25 Gt/a^2, -1.54±0.26 Gt/a^2, -0. 46±0.28 Gt/a^2 respectively, the ASE mass change rates are -89.22±1.93 Gt/a, -86.28± 2.20 Gt/a, -83.67±1.76 Gt/a with an acceleration of -10. 03±0. 65 Gt/a^2, -8.74±0. 74 Gt/a^2 and -5.69 ±0.68 Gt/a^2, and the LAS mass ehange rates are -4.31±1.95 Gt/a, -7.29±2. 84 Gt/a, 1.20±1.35 Gt/a with an acceleration of -0. 18±0.62 Gt/a^2, 3.55±0.95 Gt/a^2 and 0.97±0.49 Gt/a^2. The mass change rates derived from the three RL05 data are very close to each other both in AP and ASE with the uncertainties much smaller than the change rates, and mass losses are significantly accelerated since 2007 in AP and 2006 in ASE, respectively. However, the mass change rates are significantly different in LAS, negative rate from CSR and JPL data, but positive rate from GFZ data, the uncertainties are even larger than the correspondent change rates. With regard to the 27 drainage basins, seven basins （basin 3-9） located in the east Antarctica show positive mass change rates, and the rest twenty basins are characterized by negative mass change rates during the time span of the three RL05 data.
