2:30 PM - 2:45 PM
[ACC28-03] Distribution and seasonal evolution of supraglacial lakes on the Amery Ice Shelf, East Antarctica
Keywords:Supraglacial lakes
Melting of the Antarctic ice sheet is evident on the Antarctic Peninsula and is expected to impact the global sea level significantly. Recent satellite imagery research reveals the development of supraglacial lakes on the margins of the East Antarctic Ice Sheet (Stokes et al., 2019). The development of lakes on the East Antarctic Ice Sheet is not negligible in understanding the water balance in Antarctica. Detailed studies on the seasonal evolution of lakes’ distribution in East Antarctica have been limited to some ice shelves and ice glaciers (Langley et al., 2016; Moussavi et al., 2020). This study explored the seasonal evolution of supraglacial lakes' distribution on the Amery Ice Shelf in the East Queen Maud Land, East Antarctica.
Using Landsat 8 satellite images from 2017 to 2020, we applied Normalized Differential Water Index (NDWI) to identify supraglacial lakes on Amery Ice Shelf. Next, the geographical distribution of lakes was evaluated using the digital elevation model of Bedmap 2 (Fretwell et al., 2013). In addition, the surface temperature was calculated using satellite images. Supraglacial lakes were identified from November to February, providing the lake area of the Amery Ice Shelf. In addition, air temperature and total solar irradiance were obtained from ERA5-Land hourly data, an atmospheric reanalysis from the European Centre for Medium-Range Weather Forecasts, and the relationship with the seasonal evolution of supraglacial lakes was investigated.
We identified 16,388 super glacial lakes on the Amery Ice Shelf in January 2020. The lakes occurred mainly in the central part of the ice shelf, at low elevations (<250 m) and up to 15 km from the grounding line. However, they could exist at 1700 m elevation. of most areas where lakes occurred was from -4.0℃ to -1.0℃. This suggests that lakes can exist even below freezing. In addition, as in other areas reported (Langley et al 2016; Moussavi et al., 2020) so far, lakes started to form in late November, expanded in late December, peaked approximately in January, and shrank in late February.
We compared the temperature and total solar irradiance from ERA5-land with the formation of supraglacial lakes on the Amery Ice Shelf. The results showed that the period of increase in the total area of the lake coincided with the period of high temperature and total solar irradiance. This suggests that the formation of supraglacial lakes requires temperature and total solar irradiance, and future global warming may lead to the formation of more and more lakes.
References
P. Fretwell et al., Bedmap2: Improved ice bed, surface and thickness datasets for Antarctica, The Cryosphere, 7, 375–393, 2013.
E.S. Langley et al., Seasonal evolution of supraglacial lakes on an East Antarctic outlet glacier, Geophysical Research Letters, 43, Issue16, 8563-8571, 2016.
M. Moussavi et al., Antarctic Supraglacial Lake Detection Using Landsat 8 and Sentinel-2 Imagery: Towards Continental Generation of Lake Volumes, Remote Sens, 12, 134, 2020.
C.R. Stokes et al., Widespread distribution of supraglacial lakes around the margin of the East Antarctic Ice Sheet, Sci Rep, 9, 13823, 2019.
Using Landsat 8 satellite images from 2017 to 2020, we applied Normalized Differential Water Index (NDWI) to identify supraglacial lakes on Amery Ice Shelf. Next, the geographical distribution of lakes was evaluated using the digital elevation model of Bedmap 2 (Fretwell et al., 2013). In addition, the surface temperature was calculated using satellite images. Supraglacial lakes were identified from November to February, providing the lake area of the Amery Ice Shelf. In addition, air temperature and total solar irradiance were obtained from ERA5-Land hourly data, an atmospheric reanalysis from the European Centre for Medium-Range Weather Forecasts, and the relationship with the seasonal evolution of supraglacial lakes was investigated.
We identified 16,388 super glacial lakes on the Amery Ice Shelf in January 2020. The lakes occurred mainly in the central part of the ice shelf, at low elevations (<250 m) and up to 15 km from the grounding line. However, they could exist at 1700 m elevation. of most areas where lakes occurred was from -4.0℃ to -1.0℃. This suggests that lakes can exist even below freezing. In addition, as in other areas reported (Langley et al 2016; Moussavi et al., 2020) so far, lakes started to form in late November, expanded in late December, peaked approximately in January, and shrank in late February.
We compared the temperature and total solar irradiance from ERA5-land with the formation of supraglacial lakes on the Amery Ice Shelf. The results showed that the period of increase in the total area of the lake coincided with the period of high temperature and total solar irradiance. This suggests that the formation of supraglacial lakes requires temperature and total solar irradiance, and future global warming may lead to the formation of more and more lakes.
References
P. Fretwell et al., Bedmap2: Improved ice bed, surface and thickness datasets for Antarctica, The Cryosphere, 7, 375–393, 2013.
E.S. Langley et al., Seasonal evolution of supraglacial lakes on an East Antarctic outlet glacier, Geophysical Research Letters, 43, Issue16, 8563-8571, 2016.
M. Moussavi et al., Antarctic Supraglacial Lake Detection Using Landsat 8 and Sentinel-2 Imagery: Towards Continental Generation of Lake Volumes, Remote Sens, 12, 134, 2020.
C.R. Stokes et al., Widespread distribution of supraglacial lakes around the margin of the East Antarctic Ice Sheet, Sci Rep, 9, 13823, 2019.