Assimilating CryoSat-2 Summer Sea Ice Thickness Observations

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November 9, 2023 by Helen Hill

A collaborative team of researchers from China and Germany has enhanced the capability of a data assimilation system for estimating Arctic summer sea ice thickness. This was achieved by incorporating satellite observations of summer sea ice thickness and concentration into MITgcm.

Recent sea ice thickness observations from the CryoSat-2 have provided scientists with reliable year-round sea ice data, facilitating the assimilation of summer sea ice thickness observations. Researchers, including Chao Min, Qinghua Yang, Hao Luo, and Dake Chen from Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) in China, as well as Thomas Krumpen, Nabir Mamnun, Xiaoyu Liu, and Lars Nerger from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Germany, have successfully assimilated these latest observations into a regional Arctic configuration of the MITgcm, as documented in Min et al. (2023). Until their study, the assimilation of satellite observations of Arctic summer sea ice thickness into dynamic models was not feasible, primarily because such observations were predominantly available during the winter season.

The team used data assimilation techniques, leveraging the data assimilation capability provided by the Parallel Data Assimilation Framework (PDAF), to combine observational data with model simulation. Additionally, they utilized an incremental analysis update (IAU) approach to assimilate the biweekly CryoSat-2 summer observations. Their study offers a promising outlook for incorporating the most recent satellite observations of summer sea ice thickness into estimating and predicting Arctic sea ice. This work was recently published in Ocean-Land-Atmosphere Research, a Science Partner Journal.

“We found that directly assimilating the rather infrequent CryoSat-2 observations would introduce discontinuities in the development of sea ice volume and thickness estimates,” explains Prof. Qinghua Yang at the School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), China. “To address this challenge, we implemented an IAU approach into our data assimilation system. The IAU method guarantees a gradual development of the sea ice fields over time, enabling the assimilation of infrequent summer sea ice thickness data, which are only provided on a two-week basis, in conjunction with daily sea ice concentration data.”

By combining observations and model dynamics, the team found significant improvements in the sea ice thickness field, particularly in regions characterized by rough sea ice and intense deformation. These regions include the area surrounding the Fram Strait and the northern coast of the Canadian Arctic Archipelago and Greenland.

“Our research underscores the advantages of incorporating CryoSat-2 summer sea ice thickness data into the estimation of Arctic sea ice and, consequently, enhancing the initial conditions for sea ice predictions. This development holds great significance for marine navigation,” explains Dr. Lars Nerger at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research.

Applying the IAU scheme to summer sea ice assimilation, the team demonstrated the feasibility of reconstructing a sea ice reanalysis that assimilates satellite observations throughout the year. “We anticipate that in the future, we will be able to construct a continuous, long-term record of ice thickness with improved temporal and spatial resolution, assimilating both year-round sea ice concentration and thickness data. Moreover, with the enhanced initial sea ice conditions, our data assimilation system holds the potential to enhance sea ice predictions, particularly during the summer,” explains Prof. Yang.

To learn more about this work contact Qinghua Yang (Email:

Story image: The first assimilation of CryoSat-2 summer observations leads to significantly improved accuracy in estimating Arctic sea ice thickness.

This Month’s Featured Publication

Other New Publications last month

Buckley, M.W. et al (2023), Buoyancy forcing and the subpolar Atlantic meridional overturning circulation, Phil. Trans. R. Soc. A, doi: 10.1098/rsta.2022.0181

Alma Carolina Castillo-Trujillo et al (2023), An evaluation of eight global ocean reanalyses for the Northeast U.S. Continental shelf, Progress in Oceanography, doi: 10.1016/j.pocean.2023.103126

Zhouqian Chen et al (2023), Case study on the response of oceanic saddle-field to tropical cyclone, Deep Sea Research Part I: Oceanographic Research Papers, doi: 10.1016/j.dsr.2023.104165

Contreras, M. et al (2023), Tidal modulation of energy dissipation routes in the Gulf Stream, Geophysical Research Letters, doi: 10.1029/2023GL104946

Haine T.W.N. et al (2023), Arctic freshwater impact on the Atlantic Meridional Overturning Circulation: status and prospects, Phil. Trans. R. Soc. A, doi: 10.1098/rsta.2022.0185

David Halpern et al (2023), Comparison of ADCP and ECCOv4r4 Currents in the Pacific Equatorial Undercurrent, Journal of Atmospheric and Oceanic Technology, doi: 10.1175/JTECH-D-23-0013.1

Lei Han (2023), Exploring the AMOC Connectivity Between the RAPID and OSNAP Lines With a Model-Based Data Set, Geophysical Research Letters, doi: 10.1029/2023GL105225

Hayden, E.E. and O’Neill, L.W. (2023), Processes contributing to Bering Sea temperature variability in the late 20th and early 21st century, Journal of Climate, doi: 10.1175/JCLI-D-23-0331.1

Hörner, J. and Voigt, A. (2023), Sea-ice thermodynamics can determine waterbelt scenarios for Snowball Earth, EGUsphere, doi: 10.5194/egusphere-2023-2073

Huang L et al (2023), High-Frequency Observations of Oceanic Internal Waves from Geostationary Orbit Satellites, Ocean-Land-Atmos. Res., doi: 10.34133/olar.0024

Hughes, K.G. (2023), Fjord circulation induced by melting icebergs, EGUsphere, doi: 10.5194/egusphere-2023-2106

Kärnä, T. et al. (2023), Efficient optimization of a regional water elevation model with an automatically generated adjoint, Journal of Advances in Modeling Earth Systems, doi: 10.1029/2022MS003169

Liu, Chao (2023), Patterns & Mechanisms of Ocean Salinity Changes and Their Connection to the Climate System, University of Delaware ProQuest Dissertations Publishing,  30571615

Yu Liu et al (2023), Response of sound propagation characteristics to Luzon cold eddy coupled with tide in the Northern South China Sea, Front. Mar. Sci., doi: 10.3389/fmars.2023.1278333

Love, R. et al (2023), Exploring the climate system response to a range of freshwater representations: Hosing, Regional, and Freshwater Fingerprints, EGUsphere, doi: 10.5194/egusphere-2023-2225

Naughten, K.A. et al (2023), Unavoidable future increase in West Antarctic ice-shelf melting over the twenty-first century, Nat. Clim. Chang., doi: 10.1038/s41558-023-01818-x

Lana Opel et al (2023), A likely role for stratification in secular changes of the global ocean tides, via ResearchSquare, doi: 10.21203/

Tyler Pelle et al (2023), Subglacial discharge accelerates future retreat of Denman and Scott Glaciers, East Antarctica, Science Advances, doi: 10.1126/sciadv.adi9014

Saber Piroti et al (2023), Numerical Modeling of the Thermodynamic Effects of Sea Waters on the Corrosion in Coastal and Offshore Structures in the South of Iran, Journal of Irrigation and Water Engineering, doi: 10.22125/IWE.2023.405562.1732

A Purwandana et al (2023) IOP Conf. Ser.: Earth Environ. Sci., Hydrography and turbulent mixing in the Banda Sea inferred from Argo profiles, doi: 10.1088/1755-1315/1251/1/012007

Callum J. Shakespeare (2023), Eddy acceleration and decay driven by internal tides, Journal of Physical Oceanography, doi: 10.1175/JPO-D-23-0127.1

Hanna N. Vaidya et al (2023), Generalized Additive Models for Predicting Sea Level Rise in Coastal Florida, Geosciences, doi: 10.3390/geosciences13100310

Tobias Reiner Vonnahme et al (2023), Impact of winter freshwater from tidewater glaciers on fjords in Svalbard and Greenland; A review, Progress in Oceanography, doi: 10.1016/j.pocean.2023.103144

Bin Wang et al (2023), Feasibility of increasing marine carbon storage through olivine addition, Journal of Environmental Chemical Engineering, doi: 10.1016/j.jece.2023.111221

Wenlong Xu et al (2023), Mesoscale Eddy Modulation of Subsurface Chlorophyll Maximum Layers in the South China Sea, JGR Biogeosciences, doi: 10.1029/2023JG007648

Ryohei Yamaguchi et al (2023), Global upper ocean oxygen budget and an observational constraint on the biological pump, via ResearchSquare, doi: 10.21203/

Kaiwen Zheng et al (2023), The impact of rough topography on behaviors of mesoscale eddies as revealed by submesoscale resolving simulations, Ocean Modelling, doi: 10.1016/j.ocemod.2023.102279


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