Periodic Reporting for period 3 - CASSANDRA (Accelerating mass loss of Greenland: firn and the shifting runoff limit)
Période du rapport: 2022-05-01 au 2023-10-31
Meltwater running off the flanks of the Greenland ice sheet contributes roughly 60% to its mass loss, the rest being due to calving. Only meltwater originating from below the elevation of the runoff limit leaves the ice sheet, contributing to mass loss; melt at high elevations refreezes in the porous firn and does not drive mass loss. Therefore, any shift in the runoff limit modifies mass loss and subsequent sea level rise.
The CASSANDRA project uses computational and field methods to investigate the runoff limit as a powerful yet poorly understood modulator of Greenland mass balance. We establish a firn observation network on the Greenland ice sheet, perform detailed measurements of firn hydrology and investigate the runoff limit using remote sensing. Our results will lead to improved estimates of Greenland past, present and future mass balance.
The CASSANDRA project uses computational and field methods to investigate the runoff limit as a powerful yet poorly understood modulator of Greenland mass balance. We establish a firn observation network on the Greenland ice sheet, perform detailed measurements of firn hydrology and investigate the runoff limit using remote sensing. Our results will lead to improved estimates of Greenland past, present and future mass balance.
The project started with planning and preparation for the field campaigns. Due to the pandemic, spring 2020 fieldwork had to be cancelled but we were able to travel to Greenland in summer 2020. On the ice sheet we carried out hydrologic observation at the runoff limit. We visited the area again in spring 2021 to establish a network of 10 automatic measuring stations. A third and shorter field campaign took place in summer 2021 where the five firn stations were visited for maintenance, data download and station upgrade.
Besides the field activities, the CASSANDRA team also worked intensively with various types of satellite data. The goal of this work is to achieve a Greenland-wide understanding of the changes in surface hydrology. Publications related to our remote sensing work are currently under review or ready for submission.
Besides the field activities, the CASSANDRA team also worked intensively with various types of satellite data. The goal of this work is to achieve a Greenland-wide understanding of the changes in surface hydrology. Publications related to our remote sensing work are currently under review or ready for submission.
The CASSANDRA project is intended to shed light on the runoff limit as a powerful yet poorly understood modulator of Greenland mass balance. We develop novel methods to measure firn hydrology and permeability at the runoff limit of the Greenland ice sheet. We also developed remote sensing approaches and models that will lead to improved estimates of Greenland past, present and future mass balance.