The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen...
-
Upload
asher-sutton -
Category
Documents
-
view
216 -
download
0
Transcript of The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen...
![Page 1: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/1.jpg)
The dynamic-thermodynamic sea ice module in the
Bergen Climate ModelHelge Drange and Mats Bentsen
Nansen Environmental and Remote Sensing Center Bjerknes Centre for Climate Research
![Page 2: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/2.jpg)
Zonal mean change in surface-T in 19 CMIP-models
http://www-pcmdi.llnl.gov/cmip
!
Reasons for model differences
• Different states of natural high-latitude climate variability modes
• Variations in sea ice extent in CTRL integration
• Actual winter sea ice extent in transient integration
![Page 3: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/3.jpg)
Simulated change in surfacetemperature at 2xCO2 in
19 climate GCMs
Räisänen (2001), J. Climate, 14, 2088-2104
![Page 4: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/4.jpg)
• Miami Isopycnic Coordinate Ocean Model (MICOM; Bleck et al., 1992) - a mixture of versions 2.6 to 2.8 is used• Dynamic-thermodynamic sea ice modules included• Reference pressure at the surface• 24 model layers with potential density ranging from 23.54 to 28.10• Stretched grids with focus in the North Atlantic-Arctic region (Bentsen et al., 1999)• Daily atmospheric forcing• Daily forcing from NCEP/NCAR reanalysis (Kalnay et al., 1996)• Period 1948 to present
• Many integrations conducted: - min 80, 40 and 20 km resolution, differing by different initial conditions only
MICOM-configuration
![Page 5: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/5.jpg)
BCM-configuration, ARPEGE+MICOM• The atmospheric grid (red dots) has a resolution of T63 (2.8° by 2.8°), L31• The ocean grid (blue dots) has a resolution of 0.8° by 2.4° at the Equator,
gradually transforming to approximate square grid cells towards the poles (Mercator projection), L24 (MICOM v2.6-2.8 + dyn/thermodyn sea ice)
![Page 6: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/6.jpg)
Old 300-yr BCM-CTRL: Sea ice thickness
Winter: Too thin but realistic extent in Arctic
Summer: Too thin and too small extent
March Sep
![Page 7: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/7.jpg)
Simulated change in sea ice extent in old version of the Bergen Climate Model
Purple Control run White Doubled CO2
March September
![Page 8: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/8.jpg)
Sea ice module
• Old: Treatment of heat fluxes in atmosphere coupled/uncoupled mode were different
• New: Heat fluxes split between solar and non-solar components, with temperature-dependent tendency term for non-solar component
• New: Improved conservation of heat and fresh water
• New: WENO advection scheme
• New: Bug fixes
![Page 9: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/9.jpg)
Sea ice module in general
• Viscous-plastic rheology based on Hibler III (1979), based on the implementation of Harder (1996)
• 1 snow layer, 1 ice layer, linear temp profile in each layer
• Salinity-dependent freezing temperature
• Each grid cells accept ice and open water
• Metric terms included
0~ Hmgmf wauk
![Page 10: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/10.jpg)
Sea ice thermodynamics
![Page 11: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/11.jpg)
Short wave radiation
![Page 12: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/12.jpg)
Albedo formulations
![Page 13: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/13.jpg)
Exchange of heat between water and ice
fsrfcifmlwipww
boti TTfTTuCcQ
ST f 0.054715.273
If ,00 boti
boti QQ the is ice layer is melted (frozen) from below.
![Page 14: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/14.jpg)
Ex: Computation of sea ice temperature
![Page 15: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/15.jpg)
Simulated Arctic sea ice in the old version of NERSC-MICOM
![Page 16: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/16.jpg)
Sea ice extent anomalies, obs and simulated
Lisæter et al.
![Page 17: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/17.jpg)
Lisæter et al.
Sea ice thickness (m), obs and simulated
![Page 18: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/18.jpg)
Sea ice thickness (m), obs and simulated
Lisæter et al.
![Page 19: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/19.jpg)
Sea ice thickness (m), obs and simulated
Lisæter et al.
![Page 20: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/20.jpg)
Simulated Arctic sea ice in the first version of NERSC-MICOM
Fairly realistic anomalies in sea ice thickness and extent
Too thin sea ice, in general (not shown)
![Page 21: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/21.jpg)
Comparison: Old and new sea ice module
![Page 22: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/22.jpg)
Sea ice thickness, monthly NCEP/NACR forcing
New
OldMarch
New
OldSeptember
Both versions produce realistic sea ice extent
Thickness distribution more realistic in new version
![Page 23: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/23.jpg)
Sea ice concentration, monthly NCEP/NACR forcing
New
OldMarch
New
OldSeptember
Both versions produce realistic maximum sea ice extent
Concentration distribution more realistic in new version
![Page 24: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/24.jpg)
Example from new BCM-integration (IPCC CTRL)
![Page 25: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/25.jpg)
March September
New BCM control integration
![Page 26: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/26.jpg)
Summary
New version of the sea ice module has been implemented and tested; improved numerics + conservation of heat and fresh water + bug fixes
Improved sea ice thickness and concentration distributions
Currently used for the new IPCC-simulations
![Page 27: The dynamic-thermodynamic sea ice module in the Bergen Climate Model Helge Drange and Mats Bentsen Nansen Environmental and Remote Sensing Center Bjerknes.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649f2a5503460f94c44dcf/html5/thumbnails/27.jpg)
300-yr CTRL: SST, SSS, Arctic and Antarctic sea ice extent