Journal of Geodynamics 72 (2013) 59–66 Contents lists available at ScienceDirect Journal of Geodynamics j ourna l h om epage: http://www.elsevier.com/locate/jog Estimate of glacial isostatic adjustment uplift rate in the Tibetan Plateau from GRACE and GIA models T.Y. Zhang a,b , S.G. Jin a,∗ a Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China b University of Chinese Academy of Sciences, Beijing 100049, China a r t i c l e i n f o Article history: Received 11 November 2012 Received in revised form 23 May 2013 Accepted 24 May 2013 Available online 2 June 2013 Keywords: Glacial isostatic adjustment GRACE Tibetan Plateau a b s t r a c t The Tibetan Plateau is located in central Asia with the highest mountain and extraordinary size, where geodynamic processes are very complex. The Glacial Isostatic Adjustment (GIA) effect in the Tibetan Plateau has been highly controversial because the past and present dimensions of ice sheets are suffering from large uncertainties. Larger differences in GIA estimates are found from different models or analyses based on the possible ice sheet and glacial history in Tibet. Present-day space geodetic techniques, such as Gravity Recovery and Climate Experiment (GRACE), are able to detect the vertical mass displacement and GIA uplift. In this paper, the GIA effects in the Tibetan Plateau are estimated and evaluated with GRACE measurements and GIA models. Four global GIA models and four regional models (RM) are respectively used to estimate the GIA uplift rates with various ice sheet models and viscoelastic Earth models, which are compared with GRACE measurements. Results show that the uplift rates of GIA effects range from 1 mm/yr to 2 mm/yr in the most part of the Tibetan Plateau. The global GIA model constructed by Peltier (Peltier, 2004) provides better estimations of the GIA in the Tibetan Plateau than the other three models. © 2013 Elsevier Ltd. All rights reserved. 1. Introduction The Tibetan Plateau located in central Asia is subject to the northward push from the Indian subcontinent and the collision with Eurasian plate (e.g., Jin and Zhu, 2003; Jin and Park, 2006; Jin et al., 2007), which results in East-West expulsion and uplift (Fig. 1). The complex Tibetan Plateau called as the “Third Pole” attracts a lot of attention and different kinds of research due to its extreme size and elevation in the past. For the significant hor- izontal deformation, the GPS measurements have clearly revealed the main motion characteristics in Tibet (Wang et al., 2001). How- ever, the larger uncertainties associated with the estimation of the vertical component using GPS measurements still create difficul- ties to determine accurately the vertical motion characteristics in the past time (Jin et al., 2005). Furthermore, the vertical motion and mechanism in Tibet is very complex. Several geodynamic pro- cesses control the complicated uplift pattern in the Tibetan Plateau, including the tectonic movement, glacier isostatic adjustment and the mass loss due to the climate change. Erkan et al. (2011) stud- ied intensively and quantified the effect of these processes, which showed a significant and comparable difference to the geodetic observed signals. Recently, the uplift rates and crustal thickening ∗ Corresponding author. E-mail addresses: zhangty@shao.ac.cn (T.Y. Zhang), gnss.jin@gmail.com (S.G. Jin). rates were estimated using three stations of absolute gravimetry and three continuous GPS stations measurements, showing the mass loss in the Tibetan Plateau (Sun et al., 2009). However it is still difficult to determine the exact uplift rates due to the sparse continuous GPS sites and low resolution of the spatial distributed geodetic data. In addition, the GIA, which is the Earth’s viscoelastic response to the loading change from the glaciation and deglaciation dur- ing the glacial cycles, has big uncertainty in the Tibetan Plateau. In the past decades, it has always been very controversial whether there is a plateau-scale ice sheet as a key factor to assess the magnitude of GIA signal because of deficient precise estimates of the glaciations in Tibet. Larger differences in GIA estimates are found from different models or analyses on basis of the possible ice sheet and uncertain glacial history (Kaufmann and Lambeck, 1997; Kaufmann, 2005; Wang, 2001). They are mainly due to the input parameters limiting their forward modeling and the lack of actual and reliable observations. With the launch of the Gravity Recov- ery and Climate Experiment (GRACE) mission since 2002, it has been very successful to monitor the Earth’s time-variable gravity field and to measure Earth’s surface fluid mass redistribution (e.g., Jin et al., 2010), while GRACE also contains non-mass GIA effects. Therefore, the GRACE provides an opportunity to determine the mass balance and GIA effect in the Tibetan Plateau. In this paper the GIA uplift rates are estimated and evaluated from GRACE and other GIA models. 0264-3707/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jog.2013.05.002