After more than 6 years in full operational mode, the Gravity Recovery and Climate Experiment (GRACE) satellite mission provides the opportunity to derive global secular mass changes from space‐geodetic observations. Crucial for a reliable estimate of secular mass changes is the ability to correct for spectral and spatial leakage effects. In order to account for any leakage signal, we present and apply a four‐step procedure, including a validation step based on forward gravity modeling. Most notably, our method is characterized by the separation and quantification of individual leakage sources. We test and apply our procedure to the Greenland area, which exhibits the strongest secular trend signal. On the basis of simulation studies, we demonstrate that leakage‐out effects are dominant for the Greenland area, and if not accounted for, mass‐change rates will be underestimated. Analyzing time‐variable GRACE gravity fields covering 6 whole years (August 2002 to July 2008, inclusive), we estimate the ice‐volume loss over Greenland to be −177 ± 12 km3 a−1. This value is the average derived from monthly gravity field models provided by CSR, GFZ and JPL, with individual contributions of −242 ± 14 km3 a−1, −194 ± 24 km3 a−1 and −96 ± 23 km3 a−1, respectively. We highlight that without taking leakage effects into account, mass‐change amplitudes over Greenland are reduced by a factor of 2. Despite the rather large spread of the results among GRACE processing centers, our results are in better agreement with the findings from alternative GRACE analysis methods and InSAR observations.

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For the period July 2003 to August 2010, the interplanetary coronal mass ejection (ICME) catalogue maintained by Richardson and Cane lists 106 Earth‐directed events, which have been measured in situ by plasma and field instruments on board the ACE satellite. We present a statistical investigation of the Earth's thermospheric neutral density response by means of accelerometer measurements collected by the Gravity Recovery And Climate Experiment (GRACE) satellites, which are available for 104 ICMEs in the data set, and its relation to various geomagnetic indices and characteristic ICME parameters such as the impact speed ( vmax), southward magnetic field strength (Bz). The majority of ICMEs causes a distinct density enhancement in the thermosphere, with up to a factor of 8 compared to the preevent level. We find high correlations between ICME Bz and thermospheric density enhancements (≈0.9), while the correlation with the ICME impact speed is somewhat smaller (≈0.7). The geomagnetic indices revealing the highest correlations are Dst and SYM‐H(≈0.9); the lowest correlations are obtained for Kp and AE (≈0.7), which show a nonlinear relation with the thermospheric density enhancements. Separating the response for the shock‐sheath region and the magnetic structure of the ICME, we find that the Dst and SYM‐H reveal a tighter relation to the Bz minimum in the magnetic structure of the ICME, whereas the polar cap indices show higher correlations with the Bz minimum in the shock‐sheath region. Since the strength of the Bz component—either in the sheath or in the magnetic structure of the ICME—is highly correlated (≈0.9) with the neutral density enhancement, we discuss the possibility of satellite orbital decay estimates based on magnetic field measurements at L1, i.e., before the ICME hits the Earth magnetosphere. These results are expected to further stimulate progress in space weather understanding and applications regarding satellite operations.