Greenland Icesheet CCI Experimental Ice Uplift/Subsidence from InSAR Line-of-sight velocity
The Experimental Ice Uplift/Subsidence from InSAR Line-of-sight velocity product is a prototype product containing time series of single-pair Sentinel-1 InSAR displacement measurements. The aim of this product is to provide a product with high temporal resolution tailored to study rapidly varying and transient ice uplift/subsidence phenomena, such as those associated with subglacial water transport. Observing such phenomena on the ice cap is challenging, as the InSAR method is sensitive only to displacements in the radar line-of-sight direction, and these contain contributions from both horizontal ice flow and subsidence/uplift of the ice surface, with the horizontal flow contribution typically being much larger, and the subsidence/uplift typically appearing only sporadically and on a much smaller spatial scale. With careful interpretation, however, the product can be used for tracing subglacial water propagation pathways (by assuming the subsidence/uplift is caused by subglacial water displacing the ice surface), and, in some cases, quantify the amount of water propagating. Despite its name, the LoS-IV product actually provides a time series of vertical displacement estimates (uplift/subsidence), derived from the InSAR LoS displacement under the assumption of stable horizontal ice flow. The product contains all information necessary to easily convert the provided uplift estimate back to LoS velocity, which could be relevant, for example, if multiple products acquired from different tracks were combined to derive both horizontal flow and vertical displacement. To support such calculations, also the line-of-sight vector elevation and azimuth angles are provided in the product.
The data presented here is a prototype data product from the Greenland Icesheet Climate Change Initiative (CCI+) Phase 2. It is described in Andersen, et.al.:"Episodic Subglacial Drainage Cascades Below the Northeast Greenland Ice Stream", DOI https://doi.org/10.1029/2023gl103240. Previously, isolated data from manually identified uplift events have been published (https://doi.org/10.11583/DTU.22060061.v1) along with the paper, whereas the present dataset contains the full-grid timeseries, in order to allow potential users to familiarize themselves with this new type of product.
