DINGLAC: Mass balance, extent and velocity – Hurd & Johnsons glaciers 2020-2021

GENERAL DESCRIPTION:

The surface mass balance (SMB) monitoring programme of Hurd and Johnsons glaciers by researchers from Universidad Politécnica de Madrid was initiated in the Spanish Antarctic Campaign 2000-2001 (in its first phase for Johnsons Glacier, and in its second phase for Hurd Glacier) and has been continued since then. Since the campaign 2001-2002 (hydrological year 2002), the glacier-wide SMB data (winter balance, summer balance, annual balance, equilibrium line altitude –ELA– and accumulation area ratio –AAR) are submitted annually to the World Glacier Monitoring System –WGMS, see links below) (Navarro et al., 2022). These data are also used as input to models of surface melting (Jonsell et al., 2012).

The annual SMB surveys consist of measurements of accumulation and ablation at the net of ca. 60 stakes deployed on Hurd-Johnsons glaciers (see figure), and measurements of snow density and stratigraphy (including depth and thickness of refrozen ice layers from percolating surface meltwater) in 3-5 snow pits dug in the accumulation zone (Recio-Blitz et al., 2018), both performed close to the beginning and end of each melting season. The accumulation measurements at the stakes are complemented, since the campaign 2009-2010, by manual snow probing at ca. 50 points additional to the stake locations, to get a wider density of measurement points of snow accumulation.

More detail on the SMB measurements at the net of stakes and snow pits, and snow probing points, can be found in Navarro et al. (2013) (see link below) and Recio-Blitz et al. (2023).

As the stake positions are accurately determined, at least at the beginning and end of each campaign, by differential GNSS techniques, these repeated dGNSS measurements are also used to calculate the mean summer, winter and annual glacier surface velocities (Machío et al., 2017).

Additionally, close to the end of each campaign the following activities are performed:

- Maintenance of the net of stakes, which consists of extending those stakes in the accumulation area close to be buried by the snow, as well as re-inserting, at a deeper level, those stakes in the ablation area having only a small portion below the ice surface, so being at risk of falling. When the insertion is done in glacier ice, either a Kovacs mechanical drill or a Heucke steam drill are used.

- Measurement by differential GNSS of the front position of Argentina, las Palmas and Sally Rocks lobes/tongues of Hurd Glacier, whenever these land-terminating glacier fronts are not snow-covered. Johnsons calving front position is also determined, using photogrammetric techniques, though at more spaced time intervals of 3-5 years (Rodríguez-Cielos et al., 2016).

COMMENTS SPECIFIC TO 2020/21 CAMPAIGN:

Fieldwork operator: Kaian Fernandes
There was a single set of SMB measurements in this campaign, by late January to early February, due to COVID pandemic.

MAIN RELATED PAPERS:

Jonsell, U.Y., Navarro, F.J., Bañón, M., Lapazaran, J.J. & Otero, J. (2012). Sensitivity of a distributed temperature-radiation index melt model based on AWS observations and surface energy balance fluxes, Hurd Peninsula glaciers, Livingston Island, Antarctica. The Cryosphere, 6, 539-552, doi: 10.5194/tc-6-539-2012.

Navarro, F.J., Jonsell, U.Y., Corcuera, M.I. & Martín-Español, A. (2013). Decelerated mass loss of Hurd and Johnsons glaciers, Livingston Island, Antarctic Peninsula. J. Glaciol., 59(214), 115-128, doi: 10.3189/2013JoG12J144.

Rodríguez-Cielos, R., Aguirre de Mata, J., Díez-Galilea, A., Álvarez-Alonso, M., Rodríguez-Cielos, P. and Navarro, F.J. (2016). Geomatic methods applied to the study of the front position changes of Johnsons and Hurd Glaciers, Livingston Island, Antarctica, between 1957 and 2013. Earth Syst. Sci. Data, 8, 341-353, doi:10.5194/essd-8-341-2016.

Machío, F., Rodríguez-Cielos, R., Navarro, F., Lapazaran, J. & Otero, J. (2017). A 14-year dataset of in situ glacier surface velocities for a tidewater and a land-terminating glacier in Livingston Island, Antarctica. Earth Syst. Sci. Data, 9, 751-764, doi:10.5194/essd-9-751-2017.

Recio-Blitz, C., Navarro, F.J., Otero, J., Lapazaran, J. & González, S. (2018). Effects of recent cooling in the Antarctic Peninsula on snow density and surface mass balance. Pol. Polar Res., 39 (4), 457-480, doi:10.24425/118756.

Navarro, F., Recio-Blitz, C., Rodríguez-Cielos, R., Otero, J., Shahateet, K., De Andrés, E., Corcuera, M.I., Letamendia, U., Muñoz-Hermosilla, J.M. (2022). Surface mass balance monitoring of the peripheral glaciers of the Antarctic Peninsula in the context of regional climate change. Ann. Glaciol., 63(87-89), 101– 106, doi:10.1017/aog.2023.18.

Recio-Blitz, C., de Corcuera, M.I., Machío, F., Rodríguez-Cielos, R., Navarro, F. (2023). Response of the climatic mass balance of Hurd and Johnsons glaciers, Livingston Island, to the transient cooling period of the northern Antarctic Peninsula in the early 21st century. Czech Polar Rep., 13(2), 236-256. doi:10.5817/CPR2023-2-19.