Sub-grid-scale surface processes reduce Antarctic surface mass balance and confound interpretation of height changes | CU Experts

Sub-grid-scale processes occurring at or near the surface of an ice; sheet have a potentially large impact on local and integrated surface; mass balance (SMB) via redistribution and sublimation. Given; observational complexity, they are either ignored or parameterized over; large-length scales. Here, we train random forest models to predict 1-km; variability in snow accumulation rates over the Antarctic Ice Sheet; using atmospheric variables and topographic characteristics.; Observations of snow accumulation from both in situ and airborne radar; data provide the predictors needed to train the random forest models. We; find that sub-grid-scale processes yield a net reduction in grounded SMB; of ~50 Gt yr-1, and our model evaluation suggests this; is likely a lower bound. Spatial correlation between the predicted snow; accumulation variability with satellite-derived surface height change; indicates that sub-grid-scale processes operate differently through; time, in tandem with temporal snow accumulation anomalies.

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