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NMMB results for Test case 1: Dry baroclinic wave instability (DCMIP 4-1-X test) Vladimir Djurdjevic , Zavisa Janjic , Ratko Vasic NCEP June 2014 High Impact Weather Prediction Project (HIWPP). Dry baroclinic instability test concept and initial condition
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NMMB results for Test case 1: Dry baroclinic wave instability (DCMIP 4-1-X test) Vladimir Djurdjevic, ZavisaJanjic, RatkoVasic NCEP June 2014 High Impact Weather Prediction Project (HIWPP)
Dry baroclinic instability test concept and initial condition • Test the response of 3D atmospheric models to a controlled evolving instability (Jablonowski 2004; Jablonowski and Williamson 2006). • The balanced initial flow field comprises a zonally symmetric basic state with jet in mid-latitudes of each hemisphere and a quasi-realistic temperature distribution. • Local nonperiodic perturbation of zonal wind is defined in mid-latitudes. • Pressure at the model top ~2.26hPa
NMMB runs: • Preparation of experiment initial conditions for model grid, • Exclusion of model physics, • Transition to double precision arithmetic, (Thanks to DusanJovic and Tom Black) • Preparation of output data in NetCDF format, • 8 different experiment setups, • 4 horizontal and 2 vertical resolution (dx = 1o, 0.5o, 0.25o and 0.125o; LM=30 and 60) • We decided to run all experiments with 2, different diffusion setup (low and high), • In total 16 runs
Since there is no analytical solution of the problem, results of other models can be used to check results. • Minimum surface pressure • after day 9 (DCMIP2012) • From 940 to 960 mb • IFS close to 960 mb • Grid imprinting visible • in results of “cube” and • “hexagon” models.
NMMB Surface pressure after day 9 1o/L30 Low-diffusion run (PSmin ~940) Hi-diffusion run (PSmin ~960)
NMMB 850mb Vorticity after day 9 1o/L30 Low-diffusion run Hi-diffusion run
NMMB: surface pressure - day 15 1o/L30 Low-diffusion run Hi-diffusion run Faster growth of induced perturbation on SH in hi-diffusion run.
Transfer of perturbation to Southern hemisphere Perturbations are introduced into the Southern Hemisphere by truncation errors and by gravity waves which arise from the geostrophic adjustment associated with the imposed unbalanced perturbation in the Northern Hemisphere and which propagate into the Southern Hemisphere (Jablonowski and Williamson 2006). NMMB: Surface pressure after day 1 (1o/L30)
NMMB: surface pressure – day 20 1o/L30 Low-diffusion run Hi-diffusion run
Convergence of solution with increasing resolution
Temperature 850mb DAY 9 DAY 12 DAY 15 1o 0.5o 0.125o
Relative vorticity 850mb DAY 9 DAY 12 DAY 15 1o 0.5o 0.125o
Surface pressure DAY 6 DAY 12 DAY 15 1o 0.5o 0.125o
Comparison with two participating models in HWIPP project
Comparison with FV3 and MPAS, Surface pressure DAY 9 (1o/L30) Evolution of minimum surface pressure 100km NMMB Surface pressure (mb) FV3 MPAS Days
Comparison with FV3 and MPAS, Surface pressure (1o/L30) DAY 15 DAY 20 NMMB FV3 MPAS
Grid-imprinting on cubed-sphere and hexagon-pentagon grids “cube” “hexa” 4 corners per hemisphere 6 pentagons per hemisphere, 1 on the pole and 5 in mid-lats
NMMB Surface pressure DAY 20 South Hemisphere (1o/L30) FV3 MPAS
NMMB Temp 850mb DAY 20 South Hemisphere (1o/L30) FV3 MPAS
NMMB Relative vorticity 850mb DAY 20 South Hemisphere (1o/L30) FV3 MPAS
NMMB Temp 30 mb DAY 20 South Hemisphere (1o/L30) FV3 MPAS
NMMB Relative vorticity 10 mb DAY 20 South Hemisphere (1o/L30) FV3 MPAS
NMMB FV3 1o/L60 0.125o/L30
Problem (error) of grid imprinting is present in all variables, on all levels and in all different resolution setups, and becomes more visible as integration progresses. • Presumably problem is hard-coded in the grid geometry. • Imprint is wave-number 4 and 5 so that lateral diffusion is ineffective. • Question? • How to control, remove or extract error from solution especially during longer integrations (medium, monthly, seasonal, climate scale)?
Results for stratosphere, Vorticity at 10mb DAY 20 DAY 15 (1o/L30) NMMB FV3 MPAS
DAY 16 DAY 15 1o/L30 NMMB FV3 MPAS
DAY 16 DAY 15 1o/L30 NMMB 0.125o/L30 NMMB FV3
Conclusions • After initial model setup all experiments went smoothly without any computational problem, • Test results were according to expectations and compare favorably with other known results, • The solutions are tunable by diffusion, • Results converge with resolution, • No grid-imprinting, • No excessive noise, • NMMB scientific foundation is sound.