Zobrazeno 1 - 10
of 24
pro vyhledávání: '"Grant J. MacDonald"'
Autor:
Mansi Joshi, Alberto M. Mestas-Nuñez, Stephen F. Ackley, Stefanie Arndt, Grant J. Macdonald, Christian Haas
Publikováno v:
Remote Sensing, Vol 16, Iss 20, p 3909 (2024)
The sea ice extent in the Weddell Sea exhibited a positive trend from the start of satellite observations in 1978 until 2016 but has shown a decreasing trend since then. This study analyzes seasonal and interannual variations in sea ice thickness usi
Externí odkaz:
https://doaj.org/article/19bdf073772a4de68685f268f7cb564b
Autor:
Grant J. Macdonald, Randall K. Scharien, Kyle Duncan, Sinead L. Farrell, Parnian Rezania, Aikaterini Tavri
Publikováno v:
Geophysical Research Letters, Vol 51, Iss 4, Pp n/a-n/a (2024)
Abstract Sea ice topography information can be obtained from altimetry but these data are spatially and temporally limited compared to recent synthetic aperture radar (SAR) missions such as the RADARSAT Constellation Mission (RCM). We analyze the rel
Externí odkaz:
https://doaj.org/article/088094a0b35d4dc29474c52b7e9e1d7a
Autor:
Douglas R. MacAyeal, Olga V. Sergienko, Alison F. Banwell, Grant J. Macdonald, Ian C. Willis, Laura A. Stevens
Publikováno v:
Journal of Glaciology, Vol 67, Pp 885-902 (2021)
We develop a two-dimensional, plan-view formulation of ice-shelf flow and viscoelastic ice-shelf flexure. This formulation combines, for the first time, the shallow-shelf approximation for horizontal ice-shelf flow (and shallow-stream approximation f
Externí odkaz:
https://doaj.org/article/f560b7c12bff44e4985f1dc2f7373dd1
Publikováno v:
Annals of Glaciology, Vol 61, Pp 73-77 (2020)
Ponds that form on sea ice can cause it to thin or break-up, which can promote calving from an adjacent ice shelf. Studies of sea ice ponds have predominantly focused on Arctic ponds formed by in situ melting/ponding. Our study documents another mech
Externí odkaz:
https://doaj.org/article/f94f721ddee14ce8a09faa93423bfa06
Publikováno v:
Journal of Glaciology, Vol 66, Pp 231-247 (2020)
Diurnal depth cycles of decimeter scale are observed in a supraglacial lake on the McMurdo Ice Shelf, Antarctica. We evaluate two possible causes: (1) tidal tilt of the ice shelf in response to the underlying ocean tide, and (2) meltwater input varia
Externí odkaz:
https://doaj.org/article/3d30ba53d4174d379a77bc66888edb25
Autor:
Douglas R. MacAyeal, Alison F. Banwell, Emile A. Okal, Jinqiao Lin, Ian C. Willis, Becky Goodsell, Grant J. MacDonald
Publikováno v:
Annals of Glaciology, Vol 60, Pp 137-157 (2019)
Seismograms acquired on the McMurdo Ice Shelf, Antarctica, during an Austral summer melt season (November 2016–January 2017) reveal a diurnal cycle of seismicity, consisting of hundreds of thousands of small ice quakes limited to a 6–12 hour peri
Externí odkaz:
https://doaj.org/article/031b29c1de6a467382f06c3f1c24c4f9
Autor:
GRANT J. MACDONALD, ALISON F. BANWELL, IAN C. WILLIS, DAVID P. MAYER, BECKY GOODSELL, DOUGLAS R. MacAYEAL
Publikováno v:
Journal of Glaciology, Vol 65, Pp 337-343 (2019)
Surface debris covers much of the western portion of the McMurdo Ice Shelf and has a strong influence on the local surface albedo and energy balance. Differential ablation between debris-covered and debris-free areas creates an unusual heterogeneous
Externí odkaz:
https://doaj.org/article/422ac0aaf57d4eb5ad4be4c49eddac59
Publikováno v:
Nature Communications, Vol 10, Iss 1, Pp 1-10 (2019)
Meltwater ponding on top of ice shelves is thought to play a role in ice-shelf flexure and fracture, however in-situ evidence of these mechanisms is lacking. Here, the authors provide field-based evidence showing the impact of the filling and drainin
Externí odkaz:
https://doaj.org/article/573f9ae3e0f74643a958fbd9834c75d4
Publikováno v:
Annals of Glaciology, Vol 59, Pp 56-65 (2018)
Supraglacial lakes are known to trigger Antarctic ice-shelf instability and break-up. However, to date, no study has focused on lakes on Greenland's floating termini. Here, we apply lake boundary/area and depth algorithms to Landsat 8 imagery to anal
Externí odkaz:
https://doaj.org/article/e94adc89fe1d4faaad7226e2cb6f3a75
Autor:
Alison F. Banwell, Ian C. Willis, Grant J. Macdonald, Becky Goodsell, David P. Mayer, Anthony Powell, Douglas R. Macayeal
Publikováno v:
Annals of Glaciology, Vol 58, Pp 78-87 (2017)
On 2 March 2016, several small en échelon tabular icebergs calved from the seaward front of the McMurdo Ice Shelf, and a previously inactive rift widened and propagated by ~3 km, ~25% of its previous length, setting the stage for the future calving
Externí odkaz:
https://doaj.org/article/504432a5c88943a8ac32d826d6bbcf9a