Nab, Carmen; Mallett, Robbie; Nelson, Connor; Stroeve, Julienne; Tsamados, Michel
Optimising interannual sea ice thickness variability retrieved from CryoSat‐2 Journal Article
In: Geophys. Res. Lett., vol. 51, no. 21, 2024.
@article{Nab2024-ru,
title = {Optimising interannual sea ice thickness variability retrieved
from CryoSat‐2},
author = {Carmen Nab and Robbie Mallett and Connor Nelson and Julienne Stroeve and Michel Tsamados},
year = {2024},
date = {2024-11-01},
journal = {Geophys. Res. Lett.},
volume = {51},
number = {21},
publisher = {American Geophysical Union (AGU)},
abstract = {AbstractSatellite radar altimeters like CryoSat‐2 estimate sea
ice thickness by measuring the return‐time of transmitted radar
pulses, reflected from the sea ice and ocean surface, to measure
the radar freeboard. Converting freeboard to thickness requires
an assumption regarding the fractional depth of the snowpack
from which the radar waves backscatter . We derive sea ice
thickness from CryoSat‐2 radar freeboard data with incremental
values for , for the 2010–2021 winter periods. By comparing
these to sea ice thickness estimates derived from upward‐looking
sonar moorings, we find that values between 35%–80% result in
the best representation of interannual variability observed over
first‐year ice, reduced to 55% over multi‐year ice. The
underestimating bias in retrievals caused by optimizing this
metric can be removed by reducing the waveform retracking
threshold to 20%–50%. Our results pave the way for a new
generation of `partial penetration' sea ice thickness products
from radar altimeters.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
ice thickness by measuring the return‐time of transmitted radar
pulses, reflected from the sea ice and ocean surface, to measure
the radar freeboard. Converting freeboard to thickness requires
an assumption regarding the fractional depth of the snowpack
from which the radar waves backscatter . We derive sea ice
thickness from CryoSat‐2 radar freeboard data with incremental
values for , for the 2010–2021 winter periods. By comparing
these to sea ice thickness estimates derived from upward‐looking
sonar moorings, we find that values between 35%–80% result in
the best representation of interannual variability observed over
first‐year ice, reduced to 55% over multi‐year ice. The
underestimating bias in retrievals caused by optimizing this
metric can be removed by reducing the waveform retracking
threshold to 20%–50%. Our results pave the way for a new
generation of `partial penetration' sea ice thickness products
from radar altimeters.
Merle, Eva Le; Belot, Carole; Fouchet, Ergane; Cancet, Mathilde; Andersen, Ole Baltazar; Lyard, Florent; Moholdt, Geir; Tsamados, Michel; Hajj, Mahmoud El; Maton, Josephine; Benveniste, Jérôme; Restano, Marco
ALBATROSS: Advancing Southern Ocean tide modelling with high resolution and enhanced bathymetry Journal Article
In: Polar Sci., no. 101124, pp. 101124, 2024.
BibTeX | Tags:
@article{Le_Merle2024-dt,
title = {ALBATROSS: Advancing Southern Ocean tide modelling with high
resolution and enhanced bathymetry},
author = {Eva Le Merle and Carole Belot and Ergane Fouchet and Mathilde Cancet and Ole Baltazar Andersen and Florent Lyard and Geir Moholdt and Michel Tsamados and Mahmoud El Hajj and Josephine Maton and Jérôme Benveniste and Marco Restano},
year = {2024},
date = {2024-10-01},
journal = {Polar Sci.},
number = {101124},
pages = {101124},
publisher = {Elsevier BV},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Blockley, Ed; Fiedler, Emma; Ridley, Jeff; Roberts, Luke; West, Alex; Copsey, Dan; Feltham, Daniel; Graham, Tim; Livings, David; Rousset, Clement; Schroeder, David; Vancoppenolle, Martin
The sea ice component of GC5: coupling SI3 to HadGEM3 using conductive fluxes Journal Article
In: Geosci. Model Dev., vol. 17, no. 17, pp. 6799–6817, 2024.
@article{Blockley2024-gd,
title = {The sea ice component of GC5: coupling SI3 to HadGEM3 using conductive fluxes},
author = {Ed Blockley and Emma Fiedler and Jeff Ridley and Luke Roberts and Alex West and Dan Copsey and Daniel Feltham and Tim Graham and David Livings and Clement Rousset and David Schroeder and Martin Vancoppenolle},
year = {2024},
date = {2024-09-01},
urldate = {2024-09-01},
journal = {Geosci. Model Dev.},
volume = {17},
number = {17},
pages = {6799–6817},
publisher = {Copernicus GmbH},
abstract = {Abstract. We present an overview of the UK's Global Sea Ice
model configuration version 9 (GSI9), the sea ice component of
the latest Met Office Global Coupled model, GC5. The GC5
configuration will, amongst other uses, form the physical basis
for the HadGEM3 (Hadley Centre Global Environment Model version
3) climate model and UKESM2 (UK Earth System Model version 2)
Earth system model that will provide the Met Office Hadley
Centre/UK model contributions to CMIP7 (Coupled Model
Intercomparison Project Phase 7). Although UK ocean model
configurations have been developed for many years around the
NEMO (Nucleus for European Modelling of the Ocean) ocean
modelling framework, the GSI9 configuration is the first UK sea
ice model configuration to use the new native NEMO sea ice
model, SI3 (Sea Ice modelling Integrated Initiative). This
replaces the CICE (Community Ice CodE) model used in previous
configuration versions. In this paper we document the physical
and technical options used within the GSI9 sea ice
configuration. We provide details of the implementation of SI3
into the Met Office coupled model and the adaptations required
to work with our ``conductivity coupling'' approach and provide
a thorough description of the GC5 coupling methodology. A brief
evaluation of sea ice simulated by the GC5 model is included,
with results compared to observational references and a previous
Global Coupled model version (GC3.1) used for CMIP6, to
demonstrate the scientific credibility of the results.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
model configuration version 9 (GSI9), the sea ice component of
the latest Met Office Global Coupled model, GC5. The GC5
configuration will, amongst other uses, form the physical basis
for the HadGEM3 (Hadley Centre Global Environment Model version
3) climate model and UKESM2 (UK Earth System Model version 2)
Earth system model that will provide the Met Office Hadley
Centre/UK model contributions to CMIP7 (Coupled Model
Intercomparison Project Phase 7). Although UK ocean model
configurations have been developed for many years around the
NEMO (Nucleus for European Modelling of the Ocean) ocean
modelling framework, the GSI9 configuration is the first UK sea
ice model configuration to use the new native NEMO sea ice
model, SI3 (Sea Ice modelling Integrated Initiative). This
replaces the CICE (Community Ice CodE) model used in previous
configuration versions. In this paper we document the physical
and technical options used within the GSI9 sea ice
configuration. We provide details of the implementation of SI3
into the Met Office coupled model and the adaptations required
to work with our ``conductivity coupling'' approach and provide
a thorough description of the GC5 coupling methodology. A brief
evaluation of sea ice simulated by the GC5 model is included,
with results compared to observational references and a previous
Global Coupled model version (GC3.1) used for CMIP6, to
demonstrate the scientific credibility of the results.
Zhou, Lu; Stroeve, Julienne; Nandan, Vishnu; Willatt, Rosemary; Xu, Shiming; Zhu, Weixin; Kacimi, Sahra; Arndt, Stefanie; Yang, Zifan
Quantifying the influence of snow over sea ice morphology on L-band passive microwave satellite observations in the Southern Ocean Journal Article
In: Cryosphere, vol. 18, no. 9, pp. 4399–4434, 2024.
@article{Zhou2024-kg,
title = {Quantifying the influence of snow over sea ice morphology on
L-band passive microwave satellite observations in the Southern
Ocean},
author = {Lu Zhou and Julienne Stroeve and Vishnu Nandan and Rosemary Willatt and Shiming Xu and Weixin Zhu and Sahra Kacimi and Stefanie Arndt and Zifan Yang},
year = {2024},
date = {2024-09-01},
journal = {Cryosphere},
volume = {18},
number = {9},
pages = {4399–4434},
publisher = {Copernicus GmbH},
abstract = {Abstract. Antarctic snow on sea ice can contain slush, snow ice,
and stratified layers, complicating satellite retrieval
processes for snow depth, ice thickness, and sea ice
concentration. The presence of moist and brine-wetted snow
alters microwave snow emissions and modifies the energy and mass
balance of sea ice. This study assesses the impact of
brine-wetted snow and slush layers on L-band surface brightness
temperatures (TBs) by synergizing a snow stratigraphy model
(SNOWPACK) driven by atmospheric reanalysis data and the
RAdiative transfer model Developed for Ice and Snow in the
L-band (RADIS-L) v1.0 The updated RADIS-L v1.1 further
introduces parameterizations for brine-wetted snow and slush
layers over Antarctic sea ice. Our findings highlight the
importance of including both brine-wetted snow and slush layers
in order to accurately simulate L-band brightness temperatures,
laying the groundwork for improved satellite retrievals of snow
depth and ice thickness using satellite sensors such as Soil
Moisture and Ocean Salinity (SMOS) and Soil Moisture Active
Passive (SMAP). However, biases in modelled and observed L-band
brightness temperatures persist, which we attribute to
small-scale sea ice heterogeneity and snow stratigraphy. Given
the scarcity of comprehensive in situ snow and ice data in the
Southern Ocean, ramping up observational initiatives is
imperative to not only provide satellite validation datasets but
also improve process-level understanding that can scale up to
improving the precision of satellite snow and ice thickness
retrievals.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
and stratified layers, complicating satellite retrieval
processes for snow depth, ice thickness, and sea ice
concentration. The presence of moist and brine-wetted snow
alters microwave snow emissions and modifies the energy and mass
balance of sea ice. This study assesses the impact of
brine-wetted snow and slush layers on L-band surface brightness
temperatures (TBs) by synergizing a snow stratigraphy model
(SNOWPACK) driven by atmospheric reanalysis data and the
RAdiative transfer model Developed for Ice and Snow in the
L-band (RADIS-L) v1.0 The updated RADIS-L v1.1 further
introduces parameterizations for brine-wetted snow and slush
layers over Antarctic sea ice. Our findings highlight the
importance of including both brine-wetted snow and slush layers
in order to accurately simulate L-band brightness temperatures,
laying the groundwork for improved satellite retrievals of snow
depth and ice thickness using satellite sensors such as Soil
Moisture and Ocean Salinity (SMOS) and Soil Moisture Active
Passive (SMAP). However, biases in modelled and observed L-band
brightness temperatures persist, which we attribute to
small-scale sea ice heterogeneity and snow stratigraphy. Given
the scarcity of comprehensive in situ snow and ice data in the
Southern Ocean, ramping up observational initiatives is
imperative to not only provide satellite validation datasets but
also improve process-level understanding that can scale up to
improving the precision of satellite snow and ice thickness
retrievals.
Saddier, Louis; Palotai, Ambre; Aksil, Mathéo; Tsamados, Michel; Berhanu, Michael
Breaking of a floating particle raft by water waves Journal Article
In: Phys. Rev. Fluids, vol. 9, no. 9, 2024.
BibTeX | Tags:
@article{Saddier2024-pf,
title = {Breaking of a floating particle raft by water waves},
author = {Louis Saddier and Ambre Palotai and Mathéo Aksil and Michel Tsamados and Michael Berhanu},
year = {2024},
date = {2024-09-01},
journal = {Phys. Rev. Fluids},
volume = {9},
number = {9},
publisher = {American Physical Society (APS)},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Au, Christian; Tsamados, Michel; Manescu, Petru; Takao, So
ARISGAN: Extreme super-resolution of arctic surface imagery using generative adversarial networks Journal Article
In: Front. Remote Sens., vol. 5, 2024.
@article{Au2024-gn,
title = {ARISGAN: Extreme super-resolution of arctic surface imagery
using generative adversarial networks},
author = {Christian Au and Michel Tsamados and Petru Manescu and So Takao},
year = {2024},
date = {2024-08-01},
journal = {Front. Remote Sens.},
volume = {5},
publisher = {Frontiers Media SA},
abstract = {Introduction: This research explores the application of
generative artificial intelligence, specifically the novel
ARISGAN framework, for generating high-resolution synthetic
satellite imagery in the challenging arctic environment.
Realistic and high-resolution surface imagery in the Arctic is
crucial for applications ranging from satellite retrieval
systems to the wellbeing and safety of Inuit populations relying
on detailed surface observations.Methods: The ARISGAN framework
was designed by combining dense block, multireceptive field, and
Pix2Pix architecture. This innovative combination aims to
address the need for high-quality imagery and improve upon
existing state-of-the-art models. Various tasks and metrics were
employed to evaluate the performance of ARISGAN, with particular
attention to land-based and sea ice-based imagery.Results: The
results demonstrate that the ARISGAN framework surpasses
existing state-of-the-art models across diverse tasks and
metrics. Specifically, land-based imagery super-resolution
exhibits superior metrics compared to sea ice-based imagery when
evaluated across multiple models. These findings confirm the
ARISGAN framework's effectiveness in generating perceptually
valid high-resolution arctic surface imagery.Discussion: This
study contributes to the advancement of Earth Observation in
polar regions by introducing a framework that combines advanced
image processing techniques with a well-designed architecture.
The ARISGAN framework's ability to outperform existing models
underscores its potential. Identified limitations include
challenges in temporal synchronicity, multi-spectral image
analysis, preprocessing, and quality metrics. The discussion
also highlights potential avenues for future research,
encouraging further refinement of the ARISGAN framework to
enhance the quality and availability of high-resolution
satellite imagery in the Arctic.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
generative artificial intelligence, specifically the novel
ARISGAN framework, for generating high-resolution synthetic
satellite imagery in the challenging arctic environment.
Realistic and high-resolution surface imagery in the Arctic is
crucial for applications ranging from satellite retrieval
systems to the wellbeing and safety of Inuit populations relying
on detailed surface observations.Methods: The ARISGAN framework
was designed by combining dense block, multireceptive field, and
Pix2Pix architecture. This innovative combination aims to
address the need for high-quality imagery and improve upon
existing state-of-the-art models. Various tasks and metrics were
employed to evaluate the performance of ARISGAN, with particular
attention to land-based and sea ice-based imagery.Results: The
results demonstrate that the ARISGAN framework surpasses
existing state-of-the-art models across diverse tasks and
metrics. Specifically, land-based imagery super-resolution
exhibits superior metrics compared to sea ice-based imagery when
evaluated across multiple models. These findings confirm the
ARISGAN framework's effectiveness in generating perceptually
valid high-resolution arctic surface imagery.Discussion: This
study contributes to the advancement of Earth Observation in
polar regions by introducing a framework that combines advanced
image processing techniques with a well-designed architecture.
The ARISGAN framework's ability to outperform existing models
underscores its potential. Identified limitations include
challenges in temporal synchronicity, multi-spectral image
analysis, preprocessing, and quality metrics. The discussion
also highlights potential avenues for future research,
encouraging further refinement of the ARISGAN framework to
enhance the quality and availability of high-resolution
satellite imagery in the Arctic.
Gregory, William; MacEachern, Ronald; Takao, So; Lawrence, Isobel R; Nab, Carmen; Deisenroth, Marc Peter; Tsamados, Michel
Scalable interpolation of satellite altimetry data with probabilistic machine learning Journal Article
In: Nat. Commun., vol. 15, no. 1, pp. 7453, 2024.
@article{Gregory2024-bi,
title = {Scalable interpolation of satellite altimetry data with
probabilistic machine learning},
author = {William Gregory and Ronald MacEachern and So Takao and Isobel R Lawrence and Carmen Nab and Marc Peter Deisenroth and Michel Tsamados},
year = {2024},
date = {2024-08-01},
journal = {Nat. Commun.},
volume = {15},
number = {1},
pages = {7453},
publisher = {Springer Science and Business Media LLC},
abstract = {We present GPSat; an open-source Python programming library for
performing efficient interpolation of non-stationary satellite
altimetry data, using scalable Gaussian process techniques. We
use GPSat to generate complete maps of daily 50 km-gridded
Arctic sea ice radar freeboard, and find that, relative to a
previous interpolation scheme, GPSat offers a 504 $times$
computational speedup, with less than 4 mm difference on the
derived freeboards on average. We then demonstrate the
scalability of GPSat through freeboard interpolation at 5 km
resolution, and Sea-Level Anomalies (SLA) at the resolution of
the altimeter footprint. Interpolated 5 km radar freeboards show
strong agreement with airborne data (linear correlation of
0.66). Footprint-level SLA interpolation also shows improvements
in predictive skill over linear regression. In this work, we
suggest that GPSat could overcome the computational bottlenecks
faced in many altimetry-based interpolation routines, and hence
advance critical understanding of ocean and sea ice variability
over short spatio-temporal scales.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
performing efficient interpolation of non-stationary satellite
altimetry data, using scalable Gaussian process techniques. We
use GPSat to generate complete maps of daily 50 km-gridded
Arctic sea ice radar freeboard, and find that, relative to a
previous interpolation scheme, GPSat offers a 504 $times$
computational speedup, with less than 4 mm difference on the
derived freeboards on average. We then demonstrate the
scalability of GPSat through freeboard interpolation at 5 km
resolution, and Sea-Level Anomalies (SLA) at the resolution of
the altimeter footprint. Interpolated 5 km radar freeboards show
strong agreement with airborne data (linear correlation of
0.66). Footprint-level SLA interpolation also shows improvements
in predictive skill over linear regression. In this work, we
suggest that GPSat could overcome the computational bottlenecks
faced in many altimetry-based interpolation routines, and hence
advance critical understanding of ocean and sea ice variability
over short spatio-temporal scales.
Carter, Jeremy; Chacón-Montalván, Erick A; Leeson, Amber
Bayesian hierarchical model for bias-correcting climate models Journal Article
In: Geosci. Model Dev., vol. 17, no. 14, pp. 5733–5757, 2024.
@article{Carter2024-oz,
title = {Bayesian hierarchical model for bias-correcting climate models},
author = {Jeremy Carter and Erick A Chacón-Montalván and Amber Leeson},
year = {2024},
date = {2024-07-01},
journal = {Geosci. Model Dev.},
volume = {17},
number = {14},
pages = {5733–5757},
publisher = {Copernicus GmbH},
abstract = {Abstract. Climate models, derived from process understanding,
are essential tools in the study of climate change and its
wide-ranging impacts. Hindcast and future simulations provide
comprehensive spatiotemporal estimates of climatology that are
frequently employed within the environmental sciences community,
although the output can be afflicted with bias that impedes
direct interpretation. Post-processing bias correction
approaches utilise observational data to address this challenge,
although they are typically criticised for not being physically
justified and not considering uncertainty in the correction.
This paper proposes a novel Bayesian bias correction framework
that robustly propagates uncertainty and models underlying
spatial covariance patterns. Shared latent Gaussian processes
are assumed between the in situ observations and climate model
output, with the aim of partially preserving the covariance
structure from the climate model after bias correction, which is
based on well-established physical laws. Results demonstrate
added value in modelling shared generating processes under
several simulated scenarios, with the most value added for the
case of sparse in situ observations and smooth underlying bias.
Additionally, the propagation of uncertainty to a simulated
final bias-corrected time series is illustrated, which is of key
importance to a range of stakeholders, such as climate
scientists engaged in impact studies, decision-makers trying to
understand the likelihood of particular scenarios and
individuals involved in climate change adaption strategies where
accurate risk assessment is required for optimal resource
allocation. This paper focuses on one-dimensional simulated
examples for clarity, although the code implementation is
developed to also work on multi-dimensional input data,
encouraging follow-on real-world application studies that will
further validate performance and remaining limitations. The
Bayesian framework supports uncertainty propagation under model
adaptations required for specific applications, providing a
flexible approach that increases the scope of data assimilation
tasks more generally.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
are essential tools in the study of climate change and its
wide-ranging impacts. Hindcast and future simulations provide
comprehensive spatiotemporal estimates of climatology that are
frequently employed within the environmental sciences community,
although the output can be afflicted with bias that impedes
direct interpretation. Post-processing bias correction
approaches utilise observational data to address this challenge,
although they are typically criticised for not being physically
justified and not considering uncertainty in the correction.
This paper proposes a novel Bayesian bias correction framework
that robustly propagates uncertainty and models underlying
spatial covariance patterns. Shared latent Gaussian processes
are assumed between the in situ observations and climate model
output, with the aim of partially preserving the covariance
structure from the climate model after bias correction, which is
based on well-established physical laws. Results demonstrate
added value in modelling shared generating processes under
several simulated scenarios, with the most value added for the
case of sparse in situ observations and smooth underlying bias.
Additionally, the propagation of uncertainty to a simulated
final bias-corrected time series is illustrated, which is of key
importance to a range of stakeholders, such as climate
scientists engaged in impact studies, decision-makers trying to
understand the likelihood of particular scenarios and
individuals involved in climate change adaption strategies where
accurate risk assessment is required for optimal resource
allocation. This paper focuses on one-dimensional simulated
examples for clarity, although the code implementation is
developed to also work on multi-dimensional input data,
encouraging follow-on real-world application studies that will
further validate performance and remaining limitations. The
Bayesian framework supports uncertainty propagation under model
adaptations required for specific applications, providing a
flexible approach that increases the scope of data assimilation
tasks more generally.
Aylmer, Jake R; Ferreira, David; Feltham, Daniel L
Impact of ocean heat transport on sea ice captured by a simple energy balance model Journal Article
In: Commun. Earth Environ., vol. 5, no. 1, 2024.
@article{Aylmer2024-xe,
title = {Impact of ocean heat transport on sea ice captured by a simple
energy balance model},
author = {Jake R Aylmer and David Ferreira and Daniel L Feltham},
year = {2024},
date = {2024-07-01},
journal = {Commun. Earth Environ.},
volume = {5},
number = {1},
publisher = {Springer Science and Business Media LLC},
abstract = {AbstractFuture projections of Arctic and Antarctic sea ice
suffer from uncertainties largely associated with inter-model
spread. Ocean heat transport has been hypothesised as a source
of this uncertainty, based on correlations with sea ice extent
across climate models. However, a physical explanation of what
sets the sea ice sensitivity to ocean heat transport remains to
be uncovered. Here, we derive a simple equation using an
idealised energy-balance model that captures the emergent
relationship between ocean heat transport and sea ice in climate
models. Inter-model spread of Arctic sea ice loss depends
strongly on the spread in ocean heat transport, with a
sensitivity set by compensation of atmospheric heat transport
and radiative feedbacks. Southern Ocean heat transport exhibits
a comparatively weak relationship with Antarctic sea ice and
plays a passive role secondary to atmospheric heat transport.
Our results suggest that addressing ocean model biases will
substantially reduce uncertainty in projections of Arctic sea
ice.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
suffer from uncertainties largely associated with inter-model
spread. Ocean heat transport has been hypothesised as a source
of this uncertainty, based on correlations with sea ice extent
across climate models. However, a physical explanation of what
sets the sea ice sensitivity to ocean heat transport remains to
be uncovered. Here, we derive a simple equation using an
idealised energy-balance model that captures the emergent
relationship between ocean heat transport and sea ice in climate
models. Inter-model spread of Arctic sea ice loss depends
strongly on the spread in ocean heat transport, with a
sensitivity set by compensation of atmospheric heat transport
and radiative feedbacks. Southern Ocean heat transport exhibits
a comparatively weak relationship with Antarctic sea ice and
plays a passive role secondary to atmospheric heat transport.
Our results suggest that addressing ocean model biases will
substantially reduce uncertainty in projections of Arctic sea
ice.
Chen, Weibin; Tsamados, Michel; Willatt, Rosemary; Takao, So; Brockley, David; Rijke-Thomas, Claude; Francis, Alistair; Johnson, Thomas; Landy, Jack; Lawrence, Isobel R; Lee, Sanggyun; Shirazi, Dorsa Nasrollahi; Liu, Wenxuan; Nelson, Connor; Stroeve, Julienne C; Hirata, Len; Deisenroth, Marc Peter
Co-located OLCI optical imagery and SAR altimetry from Sentinel-3 for enhanced Arctic spring sea ice surface classification Journal Article
In: Front. Remote Sens., vol. 5, 2024.
@article{Chen2024-jh,
title = {Co-located OLCI optical imagery and SAR altimetry from
Sentinel-3 for enhanced Arctic spring sea ice surface
classification},
author = {Weibin Chen and Michel Tsamados and Rosemary Willatt and So Takao and David Brockley and Claude Rijke-Thomas and Alistair Francis and Thomas Johnson and Jack Landy and Isobel R Lawrence and Sanggyun Lee and Dorsa Nasrollahi Shirazi and Wenxuan Liu and Connor Nelson and Julienne C Stroeve and Len Hirata and Marc Peter Deisenroth},
year = {2024},
date = {2024-07-01},
journal = {Front. Remote Sens.},
volume = {5},
publisher = {Frontiers Media SA},
abstract = {The Sentinel-3A and Sentinel-3B satellites, launched in February
2016 and April 2018 respectively, build on the legacy of
CryoSat-2 by providing high-resolution Ku-band radar altimetry
data over the polar regions up to 81° North. The combination of
synthetic aperture radar (SAR) mode altimetry (SRAL instrument)
from Sentinel-3A and Sentinel-3B, and the Ocean and Land Colour
Instrument (OLCI) imaging spectrometer, results in the creation
of the first satellite platform that offers coincident optical
imagery and SAR radar altimetry. We utilise this synergy between
altimetry and imagery to demonstrate a novel application of deep
learning to distinguish sea ice from leads in spring. We use
SRAL classified leads as training input for pan-Arctic lead
detection from OLCI imagery. This surface classification is an
important step for estimating sea ice thickness and to predict
future sea ice changes in the Arctic and Antarctic regions. We
propose the use of Vision Transformers (ViT), an approach
adapting the popular deep learning algorithm Transformer, for
this task. Their effectiveness, in terms of both quantitative
metric including accuracy and qualitative metric including model
roll-out, on several entire OLCI images is demonstrated and we
show improved skill compared to previous machine learning and
empirical approaches. We show the potential for this method to
provide lead fraction retrievals at improved accuracy and
spatial resolution for sunlit periods before melt onset.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2016 and April 2018 respectively, build on the legacy of
CryoSat-2 by providing high-resolution Ku-band radar altimetry
data over the polar regions up to 81° North. The combination of
synthetic aperture radar (SAR) mode altimetry (SRAL instrument)
from Sentinel-3A and Sentinel-3B, and the Ocean and Land Colour
Instrument (OLCI) imaging spectrometer, results in the creation
of the first satellite platform that offers coincident optical
imagery and SAR radar altimetry. We utilise this synergy between
altimetry and imagery to demonstrate a novel application of deep
learning to distinguish sea ice from leads in spring. We use
SRAL classified leads as training input for pan-Arctic lead
detection from OLCI imagery. This surface classification is an
important step for estimating sea ice thickness and to predict
future sea ice changes in the Arctic and Antarctic regions. We
propose the use of Vision Transformers (ViT), an approach
adapting the popular deep learning algorithm Transformer, for
this task. Their effectiveness, in terms of both quantitative
metric including accuracy and qualitative metric including model
roll-out, on several entire OLCI images is demonstrated and we
show improved skill compared to previous machine learning and
empirical approaches. We show the potential for this method to
provide lead fraction retrievals at improved accuracy and
spatial resolution for sunlit periods before melt onset.
Bushuk, Mitchell; Ali, Sahara; Bailey, David A; Bao, Qing; Batté, Lauriane; Bhatt, Uma S; Blanchard-Wrigglesworth, Edward; Blockley, Ed; Cawley, Gavin; Chi, Junhwa; Counillon, François; Coulombe, Philippe Goulet; Cullather, Richard I; Diebold, Francis X; Dirkson, Arlan; Exarchou, Eleftheria; Göbel, Maximilian; Gregory, William; Guemas, Virginie; Hamilton, Lawrence; He, Bian; Horvath, Sean; Ionita, Monica; Kay, Jennifer E; Kim, Eliot; Kimura, Noriaki; Kondrashov, Dmitri; Labe, Zachary M; Lee, Woosung; Lee, Younjoo J; Li, Cuihua; Li, Xuewei; Lin, Yongcheng; Liu, Yanyun; Maslowski, Wieslaw; cois Massonnet, Franc; Meier, Walter N; Merryfield, William J; Myint, Hannah; Navarro, Juan C Acosta; Petty, Alek; Qiao, Fangli; Schröder, David; Schweiger, Axel; Shu, Qi; Sigmond, Michael; Steele, Michael; Stroeve, Julienne; Sun, Nico; Tietsche, Steffen; Tsamados, Michel; Wang, Keguang; Wang, Jianwu; Wang, Wanqiu; Wang, Yiguo; Wang, Yun; Williams, James; Yang, Qinghua; Yuan, Xiaojun; Zhang, Jinlun; Zhang, Yongfei
Predicting September Arctic sea ice: A multimodel seasonal skill comparison Journal Article
In: Bull. Am. Meteorol. Soc., vol. 105, no. 7, pp. E1170–E1203, 2024.
@article{Bushuk2024-rg,
title = {Predicting September Arctic sea ice: A multimodel seasonal skill
comparison},
author = {Mitchell Bushuk and Sahara Ali and David A Bailey and Qing Bao and Lauriane Batté and Uma S Bhatt and Edward Blanchard-Wrigglesworth and Ed Blockley and Gavin Cawley and Junhwa Chi and François Counillon and Philippe Goulet Coulombe and Richard I Cullather and Francis X Diebold and Arlan Dirkson and Eleftheria Exarchou and Maximilian Göbel and William Gregory and Virginie Guemas and Lawrence Hamilton and Bian He and Sean Horvath and Monica Ionita and Jennifer E Kay and Eliot Kim and Noriaki Kimura and Dmitri Kondrashov and Zachary M Labe and Woosung Lee and Younjoo J Lee and Cuihua Li and Xuewei Li and Yongcheng Lin and Yanyun Liu and Wieslaw Maslowski and Franc cois Massonnet and Walter N Meier and William J Merryfield and Hannah Myint and Juan C Acosta Navarro and Alek Petty and Fangli Qiao and David Schröder and Axel Schweiger and Qi Shu and Michael Sigmond and Michael Steele and Julienne Stroeve and Nico Sun and Steffen Tietsche and Michel Tsamados and Keguang Wang and Jianwu Wang and Wanqiu Wang and Yiguo Wang and Yun Wang and James Williams and Qinghua Yang and Xiaojun Yuan and Jinlun Zhang and Yongfei Zhang},
year = {2024},
date = {2024-07-01},
journal = {Bull. Am. Meteorol. Soc.},
volume = {105},
number = {7},
pages = {E1170–E1203},
publisher = {American Meteorological Society},
abstract = {Abstract This study quantifies the state of the art in the
rapidly growing field of seasonal Arctic sea ice prediction. A
novel multimodel dataset of retrospective seasonal predictions
of September Arctic sea ice is created and analyzed, consisting
of community contributions from 17 statistical models and 17
dynamical models. Prediction skill is compared over the period
2001–20 for predictions of pan-Arctic sea ice extent (SIE),
regional SIE, and local sea ice concentration (SIC) initialized
on 1 June, 1 July, 1 August, and 1 September. This diverse set
of statistical and dynamical models can individually predict
linearly detrended pan-Arctic SIE anomalies with skill, and a
multimodel median prediction has correlation coefficients of
0.79, 0.86, 0.92, and 0.99 at these respective initialization
times. Regional SIE predictions have similar skill to pan-Arctic
predictions in the Alaskan and Siberian regions, whereas
regional skill is lower in the Canadian, Atlantic, and central
Arctic sectors. The skill of dynamical and statistical models is
generally comparable for pan-Arctic SIE, whereas dynamical
models outperform their statistical counterparts for regional
and local predictions. The prediction systems are found to
provide the most value added relative to basic reference
forecasts in the extreme SIE years of 1996, 2007, and 2012. SIE
prediction errors do not show clear trends over time, suggesting
that there has been minimal change in inherent sea ice
predictability over the satellite era. Overall, this study
demonstrates that there are bright prospects for skillful
operational predictions of September sea ice at least 3 months
in advance.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
rapidly growing field of seasonal Arctic sea ice prediction. A
novel multimodel dataset of retrospective seasonal predictions
of September Arctic sea ice is created and analyzed, consisting
of community contributions from 17 statistical models and 17
dynamical models. Prediction skill is compared over the period
2001–20 for predictions of pan-Arctic sea ice extent (SIE),
regional SIE, and local sea ice concentration (SIC) initialized
on 1 June, 1 July, 1 August, and 1 September. This diverse set
of statistical and dynamical models can individually predict
linearly detrended pan-Arctic SIE anomalies with skill, and a
multimodel median prediction has correlation coefficients of
0.79, 0.86, 0.92, and 0.99 at these respective initialization
times. Regional SIE predictions have similar skill to pan-Arctic
predictions in the Alaskan and Siberian regions, whereas
regional skill is lower in the Canadian, Atlantic, and central
Arctic sectors. The skill of dynamical and statistical models is
generally comparable for pan-Arctic SIE, whereas dynamical
models outperform their statistical counterparts for regional
and local predictions. The prediction systems are found to
provide the most value added relative to basic reference
forecasts in the extreme SIE years of 1996, 2007, and 2012. SIE
prediction errors do not show clear trends over time, suggesting
that there has been minimal change in inherent sea ice
predictability over the satellite era. Overall, this study
demonstrates that there are bright prospects for skillful
operational predictions of September sea ice at least 3 months
in advance.
Huang, Lanqing; Hajnsek, Irena
A study of sea ice topography in the Weddell and Ross seas using dual-polarimetric TanDEM-X imagery Journal Article
In: Cryosphere, vol. 18, no. 7, pp. 3117–3140, 2024.
@article{Huang2024-kg,
title = {A study of sea ice topography in the Weddell and Ross seas using
dual-polarimetric TanDEM-X imagery},
author = {Lanqing Huang and Irena Hajnsek},
year = {2024},
date = {2024-07-01},
journal = {Cryosphere},
volume = {18},
number = {7},
pages = {3117–3140},
publisher = {Copernicus GmbH},
abstract = {Abstract. The total freeboard, which is the ice layer above
water level and includes the snow thickness, is needed to
retrieve the ice thickness and ice surface topography.
Single-pass interferometric synthetic aperture radar (InSAR)
allows for the generation of digital elevation models (DEMs)
over the drifting sea ice. However, accurate sea ice DEMs (i.e.,
the total freeboard) derived from InSAR are impeded due to
variation in the penetration of the radar signals into the snow
and ice layers. This research introduces a novel methodology for
retrieving sea ice DEMs using dual-polarization interferometric
SAR images, considering the variation in radar penetration bias
across multiple ice types. The accuracy of the method is
verified through photogrammetric measurements, demonstrating
that the derived DEM has a root-mean-square error of 0.26 m over
a 200 km $times$ 19 km area. The method is further applied to
broader regions in the Weddell Sea and the Ross Sea, offering
new insights into the regional variations of the sea ice
topography in the Antarctic. We also characterize the
non-Gaussian statistical behavior of the total freeboard using
log-normal and exponential-normal distributions. The results
suggest that the exponential-normal distribution is superior in
the thicker-sea-ice region (average total freeboard > 0.5 m),
whereas the two distributions exhibit similar performance in the
thinner-ice region (average total freeboard},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
water level and includes the snow thickness, is needed to
retrieve the ice thickness and ice surface topography.
Single-pass interferometric synthetic aperture radar (InSAR)
allows for the generation of digital elevation models (DEMs)
over the drifting sea ice. However, accurate sea ice DEMs (i.e.,
the total freeboard) derived from InSAR are impeded due to
variation in the penetration of the radar signals into the snow
and ice layers. This research introduces a novel methodology for
retrieving sea ice DEMs using dual-polarization interferometric
SAR images, considering the variation in radar penetration bias
across multiple ice types. The accuracy of the method is
verified through photogrammetric measurements, demonstrating
that the derived DEM has a root-mean-square error of 0.26 m over
a 200 km $times$ 19 km area. The method is further applied to
broader regions in the Weddell Sea and the Ross Sea, offering
new insights into the regional variations of the sea ice
topography in the Antarctic. We also characterize the
non-Gaussian statistical behavior of the total freeboard using
log-normal and exponential-normal distributions. The results
suggest that the exponential-normal distribution is superior in
the thicker-sea-ice region (average total freeboard > 0.5 m),
whereas the two distributions exhibit similar performance in the
thinner-ice region (average total freeboard
Stroeve, Julienne; Crawford, Alex; Ferguson, Steve; Stirling, Ian; Archer, Louise; York, Geoffrey; Babb, David; Mallett, Robbie
Ice-free period too long for Southern and Western Hudson Bay polar bear populations if global warming exceeds 1.6 to 2.6 °C Journal Article
In: Commun. Earth Environ., vol. 5, no. 1, 2024.
@article{Stroeve2024-vs,
title = {Ice-free period too long for Southern and Western Hudson Bay
polar bear populations if global warming exceeds 1.6 to 2.6 °C},
author = {Julienne Stroeve and Alex Crawford and Steve Ferguson and Ian Stirling and Louise Archer and Geoffrey York and David Babb and Robbie Mallett},
year = {2024},
date = {2024-06-01},
journal = {Commun. Earth Environ.},
volume = {5},
number = {1},
publisher = {Springer Science and Business Media LLC},
abstract = {AbstractHudson Bay has warmed over 1 °C in the last 30 years.
Coincident with this warming, seasonal patterns have shifted,
with the spring sea ice melting earlier and the fall freeze-up
occurring later, leading to a month longer of ice-free
conditions. This extended ice-free period presents a significant
challenge for polar bears, as it restricts their hunting
opportunities for seals and their ability to accumulate the
necessary body weight for successful reproduction. Drawing on
the latest insights from CMIP6, our updated projections of the
ice-free period indicate a more spatially detailed and alarming
outlook for polar bear survival. Limiting global warming to 2 °C
above pre-industrial levels may prevent the ice-free period from
exceeding 183 days in both western and southern Hudson Bay,
providing some optimism for adult polar bear survival. However,
with longer ice-free periods already substantially impacting
recruitment, extirpation for polar bears in this region may
already be inevitable.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Coincident with this warming, seasonal patterns have shifted,
with the spring sea ice melting earlier and the fall freeze-up
occurring later, leading to a month longer of ice-free
conditions. This extended ice-free period presents a significant
challenge for polar bears, as it restricts their hunting
opportunities for seals and their ability to accumulate the
necessary body weight for successful reproduction. Drawing on
the latest insights from CMIP6, our updated projections of the
ice-free period indicate a more spatially detailed and alarming
outlook for polar bear survival. Limiting global warming to 2 °C
above pre-industrial levels may prevent the ice-free period from
exceeding 183 days in both western and southern Hudson Bay,
providing some optimism for adult polar bear survival. However,
with longer ice-free periods already substantially impacting
recruitment, extirpation for polar bears in this region may
already be inevitable.
Li, Ruidong; Sun, Ting; Ghaffarian, Saman; Tsamados, Michel; Ni, Guangheng
GLAMOUR: GLobAl building MOrphology dataset for URban hydroclimate modelling Journal Article
In: Sci. Data, vol. 11, no. 1, pp. 618, 2024.
@article{Li2024-si,
title = {GLAMOUR: GLobAl building MOrphology dataset for URban
hydroclimate modelling},
author = {Ruidong Li and Ting Sun and Saman Ghaffarian and Michel Tsamados and Guangheng Ni},
year = {2024},
date = {2024-06-01},
journal = {Sci. Data},
volume = {11},
number = {1},
pages = {618},
publisher = {Springer Science and Business Media LLC},
abstract = {Understanding building morphology is crucial for accurately
simulating interactions between urban structures and
hydroclimate dynamics. Despite significant efforts to generate
detailed global building morphology datasets, there is a lack of
practical solutions using publicly accessible resources. In this
work, we present GLAMOUR, a dataset derived from open-source
Sentinel imagery that captures the average building height and
footprint at a resolution of 0.0009° across urbanized areas
worldwide. Validated in 18 cities, GLAMOUR exhibits superior
accuracy with median root mean square errors of 7.5 m and 0.14
for building height and footprint estimations, indicating better
overall performance against existing published datasets. The
GLAMOUR dataset provides essential morphological information of
3D building structures and can be integrated with other datasets
and tools for a wide range of applications including 3D building
model generation and urban morphometric parameter derivation.
These extended applications enable refined hydroclimate
simulation and hazard assessment on a broader scale and offer
valuable insights for researchers and policymakers in building
sustainable and resilient urban environments prepared for future
climate adaptation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
simulating interactions between urban structures and
hydroclimate dynamics. Despite significant efforts to generate
detailed global building morphology datasets, there is a lack of
practical solutions using publicly accessible resources. In this
work, we present GLAMOUR, a dataset derived from open-source
Sentinel imagery that captures the average building height and
footprint at a resolution of 0.0009° across urbanized areas
worldwide. Validated in 18 cities, GLAMOUR exhibits superior
accuracy with median root mean square errors of 7.5 m and 0.14
for building height and footprint estimations, indicating better
overall performance against existing published datasets. The
GLAMOUR dataset provides essential morphological information of
3D building structures and can be integrated with other datasets
and tools for a wide range of applications including 3D building
model generation and urban morphometric parameter derivation.
These extended applications enable refined hydroclimate
simulation and hazard assessment on a broader scale and offer
valuable insights for researchers and policymakers in building
sustainable and resilient urban environments prepared for future
climate adaptation.
Shakesby, Richard A; Cornford, Stephen L; Hiemstra, John F
Was there a low-altitude Younger Dryas Stadial glacier in south-east Wales? Re-interpretation of landforms and palaeo-climatic inferences Journal Article
In: Proc. Geol. Assoc., vol. 135, no. 3, pp. 301–309, 2024.
BibTeX | Tags:
@article{Shakesby2024-me,
title = {Was there a low-altitude Younger Dryas Stadial glacier in
south-east Wales? Re-interpretation of landforms and
palaeo-climatic inferences},
author = {Richard A Shakesby and Stephen L Cornford and John F Hiemstra},
year = {2024},
date = {2024-06-01},
journal = {Proc. Geol. Assoc.},
volume = {135},
number = {3},
pages = {301–309},
publisher = {Elsevier BV},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Diamond, Rachel; Sime, Louise C; Holmes, Caroline R; Schroeder, David
CMIP6 models rarely simulate Antarctic winter sea‐ice anomalies as large as observed in 2023 Journal Article
In: Geophys. Res. Lett., vol. 51, no. 10, 2024.
@article{Diamond2024-eb,
title = {CMIP6 models rarely simulate Antarctic winter sea‐ice
anomalies as large as observed in 2023},
author = {Rachel Diamond and Louise C Sime and Caroline R Holmes and David Schroeder},
year = {2024},
date = {2024-05-01},
journal = {Geophys. Res. Lett.},
volume = {51},
number = {10},
publisher = {American Geophysical Union (AGU)},
abstract = {AbstractIn 2023, Antarctic sea‐ice extent (SIE) reached record
lows, with winter SIE falling to 2.5Mkm2 below the satellite era
average. With this multi‐model study, we investigate the
occurrence of anomalies of this magnitude in latest‐generation
global climate models. When these anomalies occur, SIE takes
decades to recover: this indicates that SIE may transition to a
new, lower, state over the next few decades. Under internal
variability alone, models are extremely unlikely to simulate
these anomalies, with return period >1000 years for most models.
The only models with return period},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
lows, with winter SIE falling to 2.5Mkm2 below the satellite era
average. With this multi‐model study, we investigate the
occurrence of anomalies of this magnitude in latest‐generation
global climate models. When these anomalies occur, SIE takes
decades to recover: this indicates that SIE may transition to a
new, lower, state over the next few decades. Under internal
variability alone, models are extremely unlikely to simulate
these anomalies, with return period >1000 years for most models.
The only models with return period
Stroeve, J C; Veyssiere, G; Nab, C; Light, B; Perovich, D; Laliberté, J; Campbell, K; Landy, J; Mallett, R; Barrett, A; Liston, G E; Haddon, A; Wilkinson, J
Mapping potential timing of ice algal blooms from satellite Journal Article
In: Geophys. Res. Lett., vol. 51, no. 8, 2024.
@article{Stroeve2024-lq,
title = {Mapping potential timing of ice algal blooms from satellite},
author = {J C Stroeve and G Veyssiere and C Nab and B Light and D Perovich and J Laliberté and K Campbell and J Landy and R Mallett and A Barrett and G E Liston and A Haddon and J Wilkinson},
year = {2024},
date = {2024-04-01},
journal = {Geophys. Res. Lett.},
volume = {51},
number = {8},
publisher = {American Geophysical Union (AGU)},
abstract = {AbstractAs Arctic sea ice and its overlying snow cover thin,
more light penetrates into the ice and upper ocean, shifting the
phenology of algal growth within the bottom of sea ice, with
cascading impacts on higher trophic levels of the Arctic marine
ecosystem. While field data or autonomous observatories provide
direct measurements of the coupled sea ice‐algal system, they
are limited in space and time. Satellite observations of key sea
ice variables that control the amount of light penetrating
through sea ice offer the possibility to map the under‐ice light
field across the entire Arctic basin. This study provides the
first satellite‐based estimates of potential sea ice‐associated
algal bloom onset dates since the launch of CryoSat‐2 and
explores how a changing snowpack may have shifted bloom onset
timings over the last four decades.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
more light penetrates into the ice and upper ocean, shifting the
phenology of algal growth within the bottom of sea ice, with
cascading impacts on higher trophic levels of the Arctic marine
ecosystem. While field data or autonomous observatories provide
direct measurements of the coupled sea ice‐algal system, they
are limited in space and time. Satellite observations of key sea
ice variables that control the amount of light penetrating
through sea ice offer the possibility to map the under‐ice light
field across the entire Arctic basin. This study provides the
first satellite‐based estimates of potential sea ice‐associated
algal bloom onset dates since the launch of CryoSat‐2 and
explores how a changing snowpack may have shifted bloom onset
timings over the last four decades.
Alevropoulos-Borrill, Alanna; Golledge, Nicholas R; Cornford, Stephen L; Lowry, Daniel P; Krapp, Mario
Sustained ocean cooling insufficient to reverse sea level rise from Antarctica Journal Article
In: Commun. Earth Environ., vol. 5, no. 1, 2024.
@article{Alevropoulos-Borrill2024-ju,
title = {Sustained ocean cooling insufficient to reverse sea level rise
from Antarctica},
author = {Alanna Alevropoulos-Borrill and Nicholas R Golledge and Stephen L Cornford and Daniel P Lowry and Mario Krapp},
year = {2024},
date = {2024-04-01},
journal = {Commun. Earth Environ.},
volume = {5},
number = {1},
publisher = {Springer Science and Business Media LLC},
abstract = {AbstractGlobal mean sea level has risen at an accelerating rate
in the last decade and will continue to rise for centuries. The
Amundsen Sea Embayment in West Antarctica is a critical region
for present and future ice loss, however most studies consider
only a worst-case future for the region. Here we use ice sheet
model sensitivity experiments to investigate the centennial
scale implications of short-term periods of enhanced ocean
driven sub-ice shelf melting on ice loss and assess what future
reduction in melting is necessary to mitigate ice stream retreat
and offset global sea level rise. Our findings reveal that
restoring elevated melt rates to present-day levels within 100
years causes rates of ice discharge to immediately decline,
thereby limiting the overall sea level contribution from the
region. However, while ice stream re-advance and slowed ice
discharge is possible with reduced basal melting, a centennial
scale increase in accumulation must occur to offset the
extensive ice loss.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
in the last decade and will continue to rise for centuries. The
Amundsen Sea Embayment in West Antarctica is a critical region
for present and future ice loss, however most studies consider
only a worst-case future for the region. Here we use ice sheet
model sensitivity experiments to investigate the centennial
scale implications of short-term periods of enhanced ocean
driven sub-ice shelf melting on ice loss and assess what future
reduction in melting is necessary to mitigate ice stream retreat
and offset global sea level rise. Our findings reveal that
restoring elevated melt rates to present-day levels within 100
years causes rates of ice discharge to immediately decline,
thereby limiting the overall sea level contribution from the
region. However, while ice stream re-advance and slowed ice
discharge is possible with reduced basal melting, a centennial
scale increase in accumulation must occur to offset the
extensive ice loss.
Surawy-Stepney, Trystan; Hogg, Anna E; Cornford, Stephen L; Wallis, Benjamin J; Davison, Benjamin J; Selley, Heather L; Slater, Ross A W; Lie, Elise K; Jakob, Livia; Ridout, Andrew; Gourmelen, Noel; Freer, Bryony I D; Wilson, Sally F; Shepherd, Andrew
The effect of landfast sea ice buttressing on ice dynamic speedup in the Larsen B embayment, Antarctica Journal Article
In: Cryosphere, vol. 18, no. 3, pp. 977–993, 2024.
@article{Surawy-Stepney2024-or,
title = {The effect of landfast sea ice buttressing on ice dynamic
speedup in the Larsen B embayment, Antarctica},
author = {Trystan Surawy-Stepney and Anna E Hogg and Stephen L Cornford and Benjamin J Wallis and Benjamin J Davison and Heather L Selley and Ross A W Slater and Elise K Lie and Livia Jakob and Andrew Ridout and Noel Gourmelen and Bryony I D Freer and Sally F Wilson and Andrew Shepherd},
year = {2024},
date = {2024-03-01},
journal = {Cryosphere},
volume = {18},
number = {3},
pages = {977–993},
publisher = {Copernicus GmbH},
abstract = {Abstract. We observe the evacuation of 11-year-old landfast sea
ice in the Larsen B embayment on the East Antarctic Peninsula in
January 2022, which was in part triggered by warm atmospheric
conditions and strong offshore winds. This evacuation of sea ice
was closely followed by major changes in the calving behaviour
and dynamics of a subset of the ocean-terminating glaciers in
the region. We show using satellite measurements that, following
a decade of gradual slow-down, Hektoria, Green, and Crane
glaciers sped up by approximately 20 %–50 % between February
and the end of 2022, each increasing in speed by more than 100 m
a−1. Circumstantially, this is attributable to their transition
into tidewater glaciers following the loss of their ice shelves
after the landfast sea ice evacuation. However, a question
remains as to whether the landfast sea ice could have influenced
the dynamics of these glaciers, or the stability of their ice
shelves, through a buttressing effect akin to that of confined
ice shelves on grounded ice streams. We show, with a series of
diagnostic modelling experiments, that direct landfast sea ice
buttressing had a negligible impact on the dynamics of the
grounded ice streams. Furthermore, we suggest that the loss of
landfast sea ice buttressing could have impacted the dynamics of
the rheologically weak ice shelves, in turn diminishing their
stability over time; however, the accompanying shifts in the
distributions of resistive stress within the ice shelves would
have been minor. This indicates that this loss of buttressing by
landfast sea ice is likely to have been a secondary process in
the ice shelf disaggregation compared to, for example, increased
ocean swell or the drivers of the initial landfast sea ice
disintegration.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
ice in the Larsen B embayment on the East Antarctic Peninsula in
January 2022, which was in part triggered by warm atmospheric
conditions and strong offshore winds. This evacuation of sea ice
was closely followed by major changes in the calving behaviour
and dynamics of a subset of the ocean-terminating glaciers in
the region. We show using satellite measurements that, following
a decade of gradual slow-down, Hektoria, Green, and Crane
glaciers sped up by approximately 20 %–50 % between February
and the end of 2022, each increasing in speed by more than 100 m
a−1. Circumstantially, this is attributable to their transition
into tidewater glaciers following the loss of their ice shelves
after the landfast sea ice evacuation. However, a question
remains as to whether the landfast sea ice could have influenced
the dynamics of these glaciers, or the stability of their ice
shelves, through a buttressing effect akin to that of confined
ice shelves on grounded ice streams. We show, with a series of
diagnostic modelling experiments, that direct landfast sea ice
buttressing had a negligible impact on the dynamics of the
grounded ice streams. Furthermore, we suggest that the loss of
landfast sea ice buttressing could have impacted the dynamics of
the rheologically weak ice shelves, in turn diminishing their
stability over time; however, the accompanying shifts in the
distributions of resistive stress within the ice shelves would
have been minor. This indicates that this loss of buttressing by
landfast sea ice is likely to have been a secondary process in
the ice shelf disaggregation compared to, for example, increased
ocean swell or the drivers of the initial landfast sea ice
disintegration.
Huang, Qi; McMillan, Malcolm; Muir, Alan; Phillips, Joe; Slater, Thomas
Multipeak retracking of radar altimetry waveforms over ice sheets Journal Article
In: Remote Sens. Environ., vol. 303, no. 114020, pp. 114020, 2024.
BibTeX | Tags:
@article{Huang2024-ak,
title = {Multipeak retracking of radar altimetry waveforms over ice
sheets},
author = {Qi Huang and Malcolm McMillan and Alan Muir and Joe Phillips and Thomas Slater},
year = {2024},
date = {2024-03-01},
journal = {Remote Sens. Environ.},
volume = {303},
number = {114020},
pages = {114020},
publisher = {Elsevier BV},
keywords = {},
pubstate = {published},
tppubtype = {article}
}