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Global warming and sea level rise

Global warming and sea level rise. James Carton and Semyon Grodsky University of Maryland. Displaced pole horizontal grid. 900x720x40 = 25M grid points. State Variables: u, v, T, S, …. Time step: 20min (26K ts/yr). http://climate.lanl.gov/Models/POP/. Numerics.

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Global warming and sea level rise

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  1. Global warming and sea level rise James Carton and Semyon Grodsky University of Maryland

  2. Displaced pole horizontal grid 900x720x40 = 25M grid points State Variables: u, v, T, S, … Time step: 20min (26K ts/yr) http://climate.lanl.gov/Models/POP/

  3. Numerics • Arakawa-C grid in horizontal • Upstream advection • Leap frog time differencing • Separate internal and external modes • MPI, shared memory • Output is in netcdf v T,S u u v

  4. Model details • Mixing • KPP, bi-harmonic • Winds • ERA40 daily stress • QuikSCAT • Topography • Sandwell and Smith (etopo30) with McClean modifications for some passages • Freshwater flux • GPCP precipitation when avail., bulk formula evaporation, seasonal river discharge. Relaxation to clim. salinity under ice. • Heat flux • Bulk formula • Sea ice • Observed monthly cover 1979- • Tracers  CFCs, …

  5. Assimilation details (I) • Multivariate two-stage sequential updating algorithm • Stage I correct bias • Stage II correct state • Time increment • 10dy IUA {a digital filter}

  6. Global hydrographic observations vs depth Salinity Temperature 16,000 70,000 Depth Depth Change in data coverage

  7. Comparison of observed and analysis sea level at Naha, Japan

  8. Hawaii tides

  9. Mean temperature forecast - obs

  10. Comparison to independent observations

  11. Comparison of Sea Level spectra at Bermuda

  12. SODA Levitus et al 2005

  13. Our estimate of steric sea level rise since 1960

  14. Net surface radiative flux

  15. Our estimate of steric sea level rise since 1960 Volcanic Eruptions A EC P

  16. Linear trend in ERA40 surface wind velocity 1993-2001

  17. Conclusions • Much of the recent rise seems to be explainable by increases in the thermosteric component • The thermosteric component has substantial decadal variability • Consistent with Church et al. (2005), it seems that the decadal variability, or a significant part anyway, results from changes in net surface radiation induced by volcanic and maybe ENSO effects

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