Abstract
The ice shelf controls the ice flow and affects the rates of sea level rise. Its stability is affected by the basal channel to some extent. However, despite its importance, high spatiotemporal variation in the length of the basal channels and influencing factors remain poorly characterized. Here, we present evidence from satellite and airborne remote-sensing for the basal channel beneath the floating Nioghalvfjerdsfjorden (79 North Glacier) ice shelf in Northeast Greenland. We observe the surface depression of the ice shelf using IceBridge, which is an ongoing NASA mission to monitor changes in polar ice. We find that the basal channel corresponds with the depression. Temporal and spatial changes of the basal channels from 2000 to 2018 are obtained annually. The results show that the main influencing factor affecting the basal channel is the sea surface temperature (SST), and the major area of the channel length change is found in the midstream area of the ice shelf.
Highlights
Basal melting has a broad impact on the stability of polar ice shelves and is the main cause of ice loss [1]
Long-term, sustained and high-speed basal melt rates will cause thinning of the ice shelves, which will pose a great threat to the stability of ice shelves and ice sheets, causing the loss of polar ice and sea level rise, especially in regions where the basal melting is greatly affected by the influence of warm waters [4,5,6,7]
Through IceBridge and ICESat data verification, conclusions were obtained indicating that the main spatial change of the basal channel is concentrated in the midstream of the ice shelf
Summary
Basal melting has a broad impact on the stability of polar ice shelves and is the main cause of ice loss [1]. Research on the changes and stability of ice shelves based on a smaller scale of basal melting is very limited. By using satellite image and satellite altimetry data, the information of the basal channel can be obtained through changes in the morphological characteristics of the ice shelf surface [17,25]. Benefiting from the all-weather, long-term and wide-range technical advantages of satellite observations, using satellite imagery and altimetry data combined with limited ice-penetrating radar observations for verification is the most effective method for observing the long-term evolution process of a basal channel. To further investigate the spatial and temporal changes of the basal channel, factors such as the sea surface temperature (SST), surface melting days and calving front of the 79 NG ice shelf were analyzed and discussed
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