The ice shelves in the northern Antarctic Peninsula are highly sensitive to variations of temperature and have therefore served as indicators of global warming. In this study,we estimate the velocities of the ice shel...The ice shelves in the northern Antarctic Peninsula are highly sensitive to variations of temperature and have therefore served as indicators of global warming. In this study,we estimate the velocities of the ice shelves in the northern Antarctic Peninsula using co-registration of optically sensed images and correlation module(COSI-Corr) in the Environment for Visualizing Images(ENVI) based on Moderate Resolution Imaging Spectroradiometer(MODIS) images during 2000–2012,from which we conclude that the ice flow directions generally match the peninsulas pattern and the crevasse,ice flows mainly eastward into the Weddell Sea. The spatial pattern of velocity field exhibits an increasing trend from the western grounding line to the maximum at the middle part of the ice shelf front on Larsen C with a velocity of approximately 700 ma–1,and the velocity field shows relatively higher values in its southerly neighboring ice shelf(e.g. Smith Inlet). Additionally,ice flows are relatively quicker in the outer part of the ice shelf than in the inner parts. Temporal changes in surface velocities show a continuous increase from 2000 to 2012. It is worth noting that,the acceleration rate during 2000–2009 is relatively higher than that during 2009–2012,while the ice movement on the southern Larsen C and Smith Inlet shows a deceleration from 2009 to 2012.展开更多
We used in situ measurements and remote-sensing data sets to evaluate the mass budgets of the Lambert, Mellor and Fisher Glaciers and the basal melting and freezing rates beneath their flowbands on the Amery Ice Shelf...We used in situ measurements and remote-sensing data sets to evaluate the mass budgets of the Lambert, Mellor and Fisher Glaciers and the basal melting and freezing rates beneath their flowbands on the Amery Ice Shelf. Our findings show the Lambert and Mellor Glaciers upstream of the ANARE Lambert Glacier Basin (LGB) traverse may have positive imbalances of 3.9±2.1 Gt a-1 and 2.1±2.4 Gt a-1, respectively, while the Fisher Glacier is approximately in balance. The upstream region as a whole has a positive imbalance of 5.9±4.9 Gt a-1. The three same glaciers downstream of the ANARE LGB traverse line are in negative imbalance, where the whole downstream region has a negative imbalance of -8.5±5.8 Gt a-1. Overall the mass budgets of the Lambert, Mellor, and Fisher Glaciers are close to bal-ance, and the collective three-glacier system is also nearly in balance with a mass budget of -2.6±6.5 Gt a-1. The significant positive imbalances for the interior basin upstream of the ice-movement stations established in the early 1970s (GL line) reported previously are possibly due to an overestimate of the total accumulation and an underestimate of the ice flux through the GL line. The mean melting rate is -23.0±3.5 m ice a-1 near the southern grounding line, which decreases rapidly downstream, and transitions to refreezing at around 300 km from the southern extremity of the Amery Ice Shelf. Freezing rates along the flowbands are around 0.5±0.1 to 1.5±0.2 m ice a-1. The per-centage of ice lost from the interior by basal melting beneath the flowbands is about 80%±5%. The total basal melting and refreezing beneath the three flowbands is 50.3±7.5 Gt ice a-1 and 7.0±1.1 Gt ice a-1, respectively. We find a much larger total basal melting and net melting than the results for the whole Amery Ice Shelf derived from previous modeling and oceanographic measurements.展开更多
基金National Nature Science Foundation of China,No.41371391Chinese National Antarctic and Arctic Research Expedition,No.CHINARE2015-02-02+2 种基金Specialized Research Fund for the Doctoral Program of Higher Education of China,No.20120091110017A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)partially supported by Collaborative Innovation Center of Novel Software Technology and Industrialization
文摘The ice shelves in the northern Antarctic Peninsula are highly sensitive to variations of temperature and have therefore served as indicators of global warming. In this study,we estimate the velocities of the ice shelves in the northern Antarctic Peninsula using co-registration of optically sensed images and correlation module(COSI-Corr) in the Environment for Visualizing Images(ENVI) based on Moderate Resolution Imaging Spectroradiometer(MODIS) images during 2000–2012,from which we conclude that the ice flow directions generally match the peninsulas pattern and the crevasse,ice flows mainly eastward into the Weddell Sea. The spatial pattern of velocity field exhibits an increasing trend from the western grounding line to the maximum at the middle part of the ice shelf front on Larsen C with a velocity of approximately 700 ma–1,and the velocity field shows relatively higher values in its southerly neighboring ice shelf(e.g. Smith Inlet). Additionally,ice flows are relatively quicker in the outer part of the ice shelf than in the inner parts. Temporal changes in surface velocities show a continuous increase from 2000 to 2012. It is worth noting that,the acceleration rate during 2000–2009 is relatively higher than that during 2009–2012,while the ice movement on the southern Larsen C and Smith Inlet shows a deceleration from 2009 to 2012.
基金Sponsored by the NASA’s Polar Oceans and Ice Sheets Program, the National Natu-ral Science Foundation of China (Grant Nos. 40471028, 40231013 and 40476005)the Shu Guang Project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation (Grant No. 05SG46)
文摘We used in situ measurements and remote-sensing data sets to evaluate the mass budgets of the Lambert, Mellor and Fisher Glaciers and the basal melting and freezing rates beneath their flowbands on the Amery Ice Shelf. Our findings show the Lambert and Mellor Glaciers upstream of the ANARE Lambert Glacier Basin (LGB) traverse may have positive imbalances of 3.9±2.1 Gt a-1 and 2.1±2.4 Gt a-1, respectively, while the Fisher Glacier is approximately in balance. The upstream region as a whole has a positive imbalance of 5.9±4.9 Gt a-1. The three same glaciers downstream of the ANARE LGB traverse line are in negative imbalance, where the whole downstream region has a negative imbalance of -8.5±5.8 Gt a-1. Overall the mass budgets of the Lambert, Mellor, and Fisher Glaciers are close to bal-ance, and the collective three-glacier system is also nearly in balance with a mass budget of -2.6±6.5 Gt a-1. The significant positive imbalances for the interior basin upstream of the ice-movement stations established in the early 1970s (GL line) reported previously are possibly due to an overestimate of the total accumulation and an underestimate of the ice flux through the GL line. The mean melting rate is -23.0±3.5 m ice a-1 near the southern grounding line, which decreases rapidly downstream, and transitions to refreezing at around 300 km from the southern extremity of the Amery Ice Shelf. Freezing rates along the flowbands are around 0.5±0.1 to 1.5±0.2 m ice a-1. The per-centage of ice lost from the interior by basal melting beneath the flowbands is about 80%±5%. The total basal melting and refreezing beneath the three flowbands is 50.3±7.5 Gt ice a-1 and 7.0±1.1 Gt ice a-1, respectively. We find a much larger total basal melting and net melting than the results for the whole Amery Ice Shelf derived from previous modeling and oceanographic measurements.
