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The Greenland and Antarctic ice sheets gain and lose mass through short-lived events such as intense melt episodes or heavy snowfall. These sub-monthly variations are crucial for understanding sea-level change and regional climate processes. Current satellite gravity missions (like GRACE and GRACE-FO) measure mass change, but with a coarse monthly resolution, making it difficult to detect such rapid events.
The objective is to test whether new satellite gravity mission designs (GRACE-C, NGGM, MAGIC) can capture these events at weekly or bi-weekly scales, and better characterize their dynamics.
Figure: Greenland 2012 extreme melt event
Only the MAGIC_5d satellite configuration can clearly detect and resolve the double-peak structure of this short-lived melt episode at weekly resolution. Shorter retrieval periods greatly reduce the loss of information, revealing rapid mass change dynamics that current monthly-resolution missions cannot capture.
Method
Use daily mass-change anomalies simulated by the MAR3.12 regional climate model.
Compare the simulated signal to expected noise levels for several mission scenarios: MAGIC_5d, GRACE-C_like_5d, NGGM_5d, and GRACE/-FO.
Focus on two case studies: the extreme 2012 melt event in Greenland and the exceptional 2016 snowfall event in Antarctica.
Quantify the temporal omission error, i.e., the fraction of variability lost due to limited observation frequency.
First results
MAGIC_5d is the only configuration capable of detecting the melt event at weekly resolution and resolving its double-peak structure.
Reducing the retrieval period from 30 days to 7 days lowers the temporal omission error from about 30 % to 17–18 %.
GRACE-C_like_5d partially detects the event, but NGGM_5d and GRACE/-FO remain below the noise threshold.
Rapid events are most detectable along Greenland’s southern and western margins, where short-term variability is strongest.
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