Greenland's annual and interannual mass variations from GRACE/GRACE-FO linked with climatic indices

Abstract. The ongoing global warming threatens the Greenland Ice Sheet (GIS). The GIS exhibits an overall mass loss since 1990. This ice mass loss varies annually and interannually, reflecting the intricate interactions between the ice sheet and the atmospheric and oceanic circulations. In this study, we look at the temporal variations of the GIS mass balance, from April 2002 to the end of 2023, using data from the Gravity Recovery and Climate Experiment (GRACE) and its Follow-On (GRACE-FO) missions. We analyze the common cycles and the connections between GIS mass changes, climatic indices, and meteorological parameters, namely: North Atlantic Oscillation (NAO), Greenland Blocking Index (GBI), Atlantic Multidecadal Oscillation (AMO), temperature, precipitation, and surface albedo. Each variable is cumulated over time to align with the monthly mass variations since 2002. By applying Empirical Orthogonal Functions to mass variation data derived from the International Combination Service for Time-variable Gravity Fields (COST-G) solution, we identified five principal modes of variability, explaining 67.5 % of the total variance. The primary mode captures annual and interannual frequencies, ranging from 4 to 11 years, while subsequent modes only add information on the interannual part. Wavelet Analysis reveals significant annual correlations between ice mass changes and temperature (r = -0.88), NAO (r = 0.74) or GBI (r = -0.85). There are also notable lags such as a 3.5 year delayed response of the AMO to GIS mass variations during the 22 years of data. The delayed response can be linked to the time needed for Greenland’s lost mass of low-density water to reach the area where the AMO index is calculated. We also suggest an annual cycle connecting the GIS mass changes, the climatic indices, and the meteorological parameters. On the other hand, we observe complex interannual variations, including the role of sea surface temperature and atmospheric pressure in modulating ice mass balance, temperature, and precipitation. Results also indicate that cycles of 11 years in NAO, GBI, and temperature are strongly linked to solar activity. Furthermore, we observe cycles, lasting between 4 and 7 years, that align with studies linking them to atmospheric oscillations or the effect of the solid Earth’s internal geodynamics.