report on ice sheet modelling activities david holland courant institute of mathematical sciences...
TRANSCRIPT
![Page 1: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/1.jpg)
Report on Ice Sheet Modelling
Activities
David HollandCourant Institute of Mathematical Sciences
New York University, NY USA
Jonathan GregoryWalker Institute, Department of Meteorology, University of
Reading, UKMet Office Hadley Centre, Exeter, UK
Arctic System Modeling WorkshopUQAM, Montreal
July 17, 2009
![Page 2: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/2.jpg)
A Story of Two Ice Sheets
Greenland Ice Sheet:Long, narrow Fjords
Antarctic Ice Sheet:Wide expansive, ice shelves;
West Antarctica marine based
![Page 3: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/3.jpg)
Why does it matter? What are the obstacles to progress?
What are we doing?
![Page 4: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/4.jpg)
- Jakobshavn Isbrae retreats in 1997- Forced by the ocean
- (which was forced by the Atmosphere, the NAO)
Recent Changes: Greenland
![Page 5: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/5.jpg)
- Larsen B collapses in 2002- Forced by the surface melt ponds
- (which was forced by the Atmosphere)
Recent Changes: Antarctica
![Page 6: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/6.jpg)
- Pine Island thinning over last decade- Forced by the ocean warm waters
- (which was forced by the Atmosphere)
Recent Changes: Antarctica
![Page 7: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/7.jpg)
IPCC: Summary for Policy Makers
![Page 8: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/8.jpg)
IPCC: “Excluding future rapid…”
![Page 9: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/9.jpg)
Why does it matter? What are the obstacles to progress?
What are we doing?
![Page 10: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/10.jpg)
Is it Predictable?
Chaotic system?
Rate of Observational Progress?
Rate of Modeling Progress?
![Page 11: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/11.jpg)
Russell et al, 2006
IPCC: Antarctic Circumpolar Current
(an analog for uncertainty?)
![Page 12: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/12.jpg)
Challenges of Physics
… there remains uncertainty in the physics that controls the rate of flow of ice steams coming
from the land and feeding into the ice shelves, floating on the ocean.
![Page 13: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/13.jpg)
Challenges of Physics
1) physics of calving at ice fronts,
2) grounding line migration,
3) buttressing effects associated with ice geometry,
4) basal melting of ice-shelves, and the associated sub-ice-shelf ocean circulation.
![Page 14: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/14.jpg)
Challenges of Physics
… even regarding the comparatively well-understood processes determining ice-sheet surface mass
balance, there are substantial uncertainties.
![Page 15: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/15.jpg)
Challenges of Computation
1) how to represent on the grids of relatively coarse resolution global climate models the steep
marginal areas of ice-sheets, on which any surface melting occurs, and the coastal ocean circulation
that may impinge on ice-shelves.
2) within the ice models themselves how to represent regions of rapid dynamic changes, such as at the
grounding line.
![Page 16: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/16.jpg)
Why does it matter? What are the obstacles to progress?
What are we doing?
![Page 17: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/17.jpg)
Ice Sheet Modeling Community
West Antarctic Ice Sheet Initiative (WAIS)
![Page 18: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/18.jpg)
Ice Sheet Modeling Community
Forum for Research Into Ice Shelf Processes (FRISP)
![Page 19: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/19.jpg)
Ice Sheet Modeling Community
Ice Sheet Model Intercomparison Project (ISMIP)
![Page 20: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/20.jpg)
Recent “Sea-Level” Workshops
Evolution of the Antarctic Ice SheetRoyal Society of London, 2005
![Page 21: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/21.jpg)
Recent “Sea-Level” Workshops
Understanding Sea-Level Rise and VariabilityParis, 2006
![Page 22: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/22.jpg)
Recent “Sea-Level” Workshops
Toward a New Generation of Ice Sheet ModelsGFDL, 2007
![Page 23: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/23.jpg)
Predicting Sea Level in the 21st Century:The Role of Ice-Ocean Interaction
New York University, 2008
Recent “Sea-Level” Workshops
… to stimulate activity between
the cryospheric community and clim
ate
modelers in national laboratories …
![Page 24: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/24.jpg)
Recent “Sea-Level” Workshops
Workshop on Improving Ice Sheet ModelsSCAR, 2008
![Page 25: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/25.jpg)
Recent “Sea-Level” Workshops
Building a Next Generation Community Ice ModelLANL, 2008
![Page 26: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/26.jpg)
UK Efforts
Hadley Centre using HadCM3 coupled to the Greenland 3D ISM of Huybrechts
starting to use the Glimmer 3D ISM coupled to Hadley Centre AOGCMs
Glimmer is being developed (led by Payne), to include an adaptive-mesh high-resolution treatment of ice streams and the
grounding line
The Hadley Centre AGCM is being improved as regards ice-sheet surface mass balance
![Page 27: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/27.jpg)
EU Effort: ice2sea
proposed EU Framework 7 project on estimating the future contribution of continental ice to sea-level rise
focus on key processes not included in current models, •essential observations (especially for the satellite period),
•projection of ice-sheet surface mass balance and ice-shelf basal mass balance using regional atmosphere and ocean models,
•projection of ice-sheet response over 200 years, •and synthesis including regional sea-level projection
•and risk assessment
does not include model development, two-way coupling between ice sheet and climate (only climate->ice-sheet)
![Page 28: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/28.jpg)
LANL Efforts
developing a Community Ice Sheet Model (CISM)
implementing CISM in the Community Climate System Model (CCSM)
strategy for developing an IPCC-ready community ice sheet model in 1 to 2 years
and fully coupled model later on
![Page 29: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/29.jpg)
Conclusions: The Good
there exists an ever-growing (?) and diverse group of researchers studying ice sheets and sea level
some detectable momentum in EU and USA efforts
![Page 30: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/30.jpg)
Conclusions: The Bad
![Page 31: Report on Ice Sheet Modelling Activities David Holland Courant Institute of Mathematical Sciences New York University, NY USA Jonathan Gregory Walker Institute,](https://reader030.vdocuments.net/reader030/viewer/2022032604/56649e615503460f94b5c5af/html5/thumbnails/31.jpg)
Conclusions: The Ugly
No existing capability to model future sea level change
The capability is not obviously going to emerge anytime soon
There is no detailed plan