Download presentation
Presentation is loading. Please wait.
Published byVirginia Sherman Modified over 9 years ago
1
Sea ice modeling at met.no Keguang Wang Norwegian Meteorological Institute
2
Sea ice models at met.no NorESM (Jens) TOPAZ (Magnus) ROMS (Keguang) FRAMPS (Keguang) ROMS-CICE (Jens, Keguang,...)
3
FRAMPS model description Granular ice dynamics –2-level ice category –Curved diamond yield curve [Wang, 2007, JGR] –Levy flow rule [Wang, 2006, Annals of Glaciol.], with modifications –Particle-in-cell for advection [Wang and Wang, 2009, JGR]. Comparison between RGPS-derived and modeled shear deformations (Wang and Wang, 2009)
4
Prediction domain Pan-Arctic –10 km resolution European Arctic –Fram Strait, Svalbard, Barents Sea –2 km resolution
5
Initial sea ice concentration AMSR-2 NIC ice chart CIS ice chart interpolation for North Pole
6
Initial sea ice thickness SMOS OSISAF ice type interpolation for North Pole
7
48 hours forecast
8
forecast drift vs. CALIB_2015a (1st leg)
9
forecast drift vs. CALIB_2015c (2nd leg)
10
ROMS Nordic-4km data assimilation Operational ocean-sea ice model in met.no –TOPAZ –MIPOM –ROMS –FRAMPS Background –operational sea ice forecast system transfered from MIPOM to ROMS in 2013 –Sea ice concentration assimilated for ROMS Arctic-20km, but no yet for Nordic-4km –need for high accuracy sea ice forecast for shipping, fishing and oil and gas exploration
11
ROMS brief free-surface, terrain-following, primitive equations ocean model Very modern code, uses C-preprocessing to activate the various physical and numerical options Coupling modules for atmosphere, wave, biogeochemical, bio-optical, sediment, and sea ice applications
12
ROMS framework disgram
13
ROMS sea ice module Main developer: Budgell (2005) Two-level sea ice state EVP rheology MPDATA advection scheme One-layer ice and snow thermodynamics (Mellor and Kantha, 1989) Plume model between sea ice and water frazil ice formation (Steele et al., 1989)
14
ROMS operational system in met.no A triply nested system: –Arctic-20km → Nordic-4km → NorKyst-800m The global ocean model FOAM from UK Met Office gives the lateral boundary conditions to Arctic 20 km ECMWF forcing for Arctic-20km and Nordic-4km
15
ROMS Arctic-20km
16
ROMS Arctic-20km + Nordic-4km
17
Arctic20 + Nordic4 + NorKyst800
18
Previous Nordic-4km vs. Arctic-20km
19
Nordic-4km sea ice extent vs. ice chart ice conditions on 20150909
20
available data and uncertainties
21
combined data and std
22
Combined optimal interpolation and nudging scheme (Wang et al., 2013) Optimal Interpolation: Nudging:
23
assimilation method COIN scheme –cheap computation –no abrupt shock to the model simulation –OSISAF and ice chart are daily averaged products based on multi-sensors and multi-time –observations usually has similar or even higher spatial resolution than model –weak stability, homogeneity, isotropy of the error covariance –no spatial variation of nudging coefficient make a 5-year simulation of ROMS Arctic-20km interpolate the Arctic-20km results to Nordic-4km domain for boundary and initial fields
24
assimilated sea ice extent and mean std
25
correct rate of the simulation
26
Nordic-4km 1-day forecast skill Ice edge position ice concentration ice extent
27
Nordic-4km vs TOPAZ
30
Thanks for your attention !!!
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.