/ Rossby Centre RCAO, a coupled atmosphere ice ocean land model of the Arctic

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1 RCAO, a coupled atmosphere ice ocean land model of the Arctic R. Döscher*, K. Wyser*, M. Meier**, P. Samuelsson*, M. Qian*** *SMHI/Rossby Centre/Norrköping/Sweden **SMHI/Ocean research/norrköping/sweden ***UQAM/Montreal/Canada

2 Coupled model setup Standalone model components Atmosphere, ocean+sea ice RCO Technical coupling ocean delivers state variables, atmosphere responds with fluxes ocean OASIS tmod atmos external coupler: OASIS4 Coupling algorithm ice RCA rivers landsurf tcoup Example: RCAO coupling scheme described in: Döscher et al. 2002: The development of the coupled ocean-atmosphere model RCAO. Boreal Env. Res. 7,

3 RCO (ocean) Z-coordinates, rotated coordinates Arctic: 0.50 resolution free surface low dispersion advection Mixing options K-eps, Philander/Pacanowski, KPP Bottom boundary layer (BBL) Climatological Arctic River runoff Open boundary conditions sea ice model Semtner thermodynamics EVP rheology RCO described in: Meier, Döscher and Faxen, 2003: A multiprocessor coupled ice-ocean model for the Baltic Sea: application to salt inflow, JGR, 108 (C8), 3273

4 RCA (atmosphere) HIRLAM based regional atmosphere model optimized for climate studies: Arctic 0.50 resolution Prognostic variables: U, V, T, CW, Ps and TKE Semi-Lagrangian dynamics, 0.5 resolution 6th order implicit horizontal diffusion scheme Davies lateral boundary relaxation scheme HIRLAM fast two band radiation scheme Kain-Fritsch meso-scale convection Rasch-Kristjansson large-scale condensation Turbulent Kinetic Energy (TKE) vertical mixing scheme Has been run over the Artic in ARCMIP runs Applications in other regions (North America, Africa, collaboration partners in South America) Possible improvements: Cloudiness, radiation and turbulence in the stable boundary layer (dry-turbulence-moist turbulence) Optical properties of ice crystals (ice clouds) Surface flux representation in the stable boundary layer description in: Jones, C. G., Willén, U., Ullerstig, A. and Hansson, U. 2004: The Rossby Centre Regional Atmospheric Climate Model Part I: Model Climatology and Performance for the Present Climate over Europe. Ambio 33:4-5,

5 Arctic applications Currently: Sensitivity studies Predictability studies Regional climate scenario experiments Short term forecast (weather and sea ice), data assimilation (HIRLAM HIROMB model) future: Seasonal prediction Bio geo chemical component

6 Sea ice extent in RCAO simulations Spinup phase

7 Summer sea ice extent anomaly in four ensemble runs coupled runs ERA40 or sat observation

8 Sea ice extent summer Ensemble mean ERA-40 winter

9 Mean T2m north of 700N red RCAO ensemble black ERA 40 summer winter annual means

10 winter spring summer fall Surface pressure in standalone atmosphere and coupled model

11 Predictability t2m winter internal variability total variability external variability external/internal Dominating internal variability in Fram Strait area

12 RCO SCOBI High resolution 3 D coupled physical biogeochemical model for climate and process studies From upper layer Nitrogen fixation N2 Denitrific ation Nitrifica tion O2 H2S NO 3 NH 4 PO From upper layer Assimilatio n Assimilatio n Assimilatio n A1 A2 A3 Grazing Mortalit y ZO O Excreti on Predation 4 Decompos ition DE T Faece s Grazin g Pelagic variables: nitrate (NO3) ammonium (NH4) phosphate (PO4) autotrophs (A1,A2,A3) (diatoms, flagellates, cyanobacteria) department Sediment zooplankton (ZOO) detritus (DET) Sediment Sediment PBT ation ation oxygen (O2) Ammoni Burial To lower To lower um Hydrogen sulfide (H2S) is layer layer adsorpti on included as negative oxygen. The sediment contains nutrients in the form of benthic nitrogen (NBT) and phosphorus (PBT). Aggregated process descriptions for oxygen dependent nutrient regeneration, denitrification and adsorption of ammonium to sediment particles as well as re suspension and permanent burial of organic matter. Denitrific ation Nitrifica tion Decomposition NB T Resuspen sion Meier, Eilola, Almroth SMHI

13 Regionalization is done for time slices from GCMs Regional simulations Results archived from a GCM run CO2 Time Present day or a Climate scenario control climate ( ) ( )

14 Annual mean phytoplankton concentration [mgchl/m3 ] (0 10m) for different nutrient load reduction scenarios Reference ( ) Best case BSAP Business as usual Present climate ECHAM4/A2 Meier, Eilola, Almroth SMHI

15 Comming activities Modell improvements cloud - radiation scheme (SLP bias problem) Improved vertical mixing in the ocean Ice classes Additional predictability - studier under different parameterizations different climates Hindcast runs driven with improved reanalysis products (ERAinterim) RCO (ocean-ice standalone) runs of 20th century within AOMIP Regional Arctic climate scenarios, based on Bergen Climate model (BCM) and other GCMs. Simulations of 2007/2008 (RCO and RCAO) RCAO as an ASM: SCOBI_Arctic

16 The End

The Rossby Centre Ocean model applied to the Arctic Ocean using ERA-40

The Rossby Centre Ocean model applied to the Arctic Ocean using ERA-40 The Ocean model applied to the Arctic Ocean using ERA-40 H.E. Markus Meier, R. Döscher, K. Wyser /SMHI, Norrköping and K. Döös MISU, Stockholm University, Stockholm Ocean model (RCO) based on the BRYAN-COX-SEMTNER