Zemin Wang, Mingliang Liu, Baojun Zhang, Xiangyu Song, Jiachun An. Temporal and spatial changes of the basal channel of the Getz ice shelf in Antarctica derived from multi-source data[J]. Acta Oceanologica Sinica.
Citation:
Zemin Wang, Mingliang Liu, Baojun Zhang, Xiangyu Song, Jiachun An. Temporal and spatial changes of the basal channel of the Getz ice shelf in Antarctica derived from multi-source data[J]. Acta Oceanologica Sinica.
Zemin Wang, Mingliang Liu, Baojun Zhang, Xiangyu Song, Jiachun An. Temporal and spatial changes of the basal channel of the Getz ice shelf in Antarctica derived from multi-source data[J]. Acta Oceanologica Sinica.
Citation:
Zemin Wang, Mingliang Liu, Baojun Zhang, Xiangyu Song, Jiachun An. Temporal and spatial changes of the basal channel of the Getz ice shelf in Antarctica derived from multi-source data[J]. Acta Oceanologica Sinica.
Chinese Antarctic Center of Surveying and Mapping, Wuhan University, Wuhan 430079, China
2.
School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
3.
Key Laboratory of Roads and Railway Engineering Safety Control (Shijiazhuang Tiedao University), Ministry of Education, Shijiazhuang 050043, China
Funds:
The National Natural Science Foundation of China under contract Nos 41941010 and 42006184; the Independent Scientific Research Project of the State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing.
Basal melting is an important factor affecting the stability of the ice shelf. The basal channel is formed from uneven melting, which also has an important impact on the stability of the ice shelf. Therefore, it has important scientific value to study the basal channel changes. This study combined datasets of Mosaics of Antarctica, Reference Elevation Model of Antarctica (REMA) and Operation IceBridge to study the temporal and Spatial changes of basal channels at the Getz ice shelf in Antarctica. The relationships between the cross-sectional area and width of basal channel and those of its corresponding surface depression were statistically analyzed. Then, the changes of the basal channels of Getz ice shelf were derived from the ICESat observations and REMA digital elevation models (DEMs). After a detailed analysis of the factors affecting the basal channel changes, we found that the basal channels of Getz ice shelf were mainly concentrated in the eastern of the ice shelf, and most of them belonged to the ocean-sourced basal channel. From 2009 to 2016, the total length of the basal channel has increased by approximately 60 km. Affected by the warm Circumpolar Deep Water (CDW), significant changes in the basal channel occurred in the middle reaches of the Getz ice shelf. The change of the basal channels at the edge of the Getz ice shelf is significantly weaker than that in its middle and upper reaches. Especially in 2005–2012, the eastward wind on the ocean wind field and the westward wind around the continental shelf caused the invasion and upwelling of CDW. Meanwhile, the continuous warming of deep seawater also caused the deepening of the basal channel. During from 2012 to 2020, the fluctuations of the basal channels seem to be caused by the changes in temperature of CDW.
Figure 1. Outline map of the eastern part of the Getz ice shelf. The background image is a REMA hillshade map. The blue rectangle indicates the intersection of the ICESat orbit and the recessed surface of the ice shelf. The Colored thin lines indicate NASA OIB trajectories. The colored thick lines indicate the trajectories of ICESat-1 and ICESat-2, mark with white letters. The location of the analysis point is marked with black letters. The green point is location of surface elevation change due to surface process from the Institute for Marine and Atmospheric Research Utrecht Firn Densification Model (IMAU-FDM) (Ligtenberg et al., 2011, 2014).
Figure 2. Distribution of basal channels of the Getz ice shelf in 2009 (a) and 2016 (b). c. Basal channels discrimination using OIB MCoRDS measurements. The gray marked part is the corresponding position of the basal channel. d. Statistics of basal channels length.
Figure 3. The geometric relationship between the basal channels and the surface depression. a.Comparison of the cross-sectional area of the IceBridge trajectories across basal channels and those of the corresponding surface depression. The blue line is the linear fit as described by the linear relationship for the corresponding regression equation. The red line is their relationship when they are in hydrodynamic equilibrium; b. comparison of the cross-sectional width of the IceBridge trajectories across basal channels and those of the corresponding surface depression. The blue line is the linear fit as described by the linear relationship for the corresponding regression equation. The red line is their relationship when they are in hydrodynamic equilibrium.
Figure 5. Schematic diagram of determining the basal channel position through IceBridge data, corresponding to the position of the black letter mark in Fig. 1.
Figure 6. The elevation time series of the surface depression at transects areas of a–f (a–f, respectively) shown in Fig. 1 by combining ICESat-1, ICESat-2, and REMA DEMs.
Figure 7. The long time series of the basal channels at transects areas of a–f (a–f, respectively) shown in Fig. 1 by combining ICESat-1, ICESat-2, and REMA DEMs.
Figure 8. The mean surface seawater temperature in different years from 2003 to 2020 at the eastern frontier of the Getz ice shelf.
Figure 9. Representative wind field data of some months during from 2003 to 2020 of near the east of the Getz ice shelf.
Figure 10. Seawater temperature at depth of 1 000 m at the eastern tip of the Getz ice shelf.
DownLoad:
