Justin GlisanIowa State University

Department of Geological and Atmospheric Sciences

RACM Project Update: ISU Atmospheric Modeling Component: Part 1

6th DOE/RACM Meeting: Boulder, CO 1Justin Glisan, Iowa State University

Outline• Update since Santa Cruz• CORDEX Production runs

– Era-Interim Reanalysis – 1989 - 2007– Arctic CORDEX Domain– Six member ensemble

• Observational Analysis of Extremes• Spectral Nudging on the wr50a domain

2Justin Glisan, Iowa State University

Update since Santa Cruz

• Three inter-connected projects– CORDEX production runs– Observational analysis of extremes– Spectral nudging (Based on Matt Higgins work at

CU)• Running RACM CCSM12 on Pingo

CORDEX Production Runs

CU physicsEra-Interim Reanalysis

NSIDC sea ice

4Justin Glisan, Iowa State University

PAW on Arctic CORDEX

• WRFV3.1.0 w/ CU Physics • Arctic CORDEX Domain• Forcing data sets:

– Era-Interim Reanalysis – NSIDC Bootstrap Fractional Sea Ice

• Six-member ensemble – One day stagger (01-06 January 1989)– January 1989 - December 2007

Justin Glisan, Iowa State University 5

January 1999 July 1999

January 2007 July 2007

Obs. RMSD and Variability

• Reanalysis RMSD provides another measure of internal variability in the atmosphere

• Magnitudes of both RMSD curves correspond to a high degree, including the seasonal variability.

• Thus, the model versus reanalysis RMSD:• May have a considerable dependence on

unforced, quasi-random internal variability• Also simulates the annual cycle of that variability

17Justin Glisan, Iowa State University

Observational Analysis of Extremes

North American stationsPrecipitation and Temperature

Domain of Interest

• Arctic CORDEX Domain (1989 - 2007)• NCDS Global Summary of the Day

– Around 150 stations– Precipitation and Temperature

• Four analysis boxes– Based on the climatological record, weather

patterns– Physical location within the domain

• Each station is considered an individual realization within each box; hence each realization has a large number of samples, adding many degrees of freedom for statistical analysis.

• Observations are ordered and ranked by precipitation amount or temperature and then using the 95th percentile the extreme values are found using a suite of statistical programs. Further analysis is performed to determine extreme temporal and spatial regimes in temperature and precipitation.

Spectral Nudging on wr50a Domain

RACM Atmospheric DomainFour different nudging coefficients

PAW Setup on wr50a• WRFV3.1.1 w/ CU physics• Full spectral nudging option• Three-member ensemble (one day stagger)• Two cases:

– Winter case: January 2007 (initialized in Dec.)– Summer case: July 2007 (initialized in June)

• Four nudging coefficients – Full (WRF default)– 1/2, 1/4, 1/8

ISU Polar WRF

Brandon FiselIowa State University

Department of Geological and Atmospheric Sciences

RACM May 2010

Outline

RACM May 2010

• Motivations• Model setup• Short-term behavior• Longer simulation results

Definitions

RACM May 2010

Binary Fraction0 0% - 49%1 50% - 100%

Motivations

RACM May 2010

• WRF sea-ice:• fraction v. binary

• Fractions • ocean-atmosphere interactions• dynamical behavior• climatological behavior

2007, July Sea Ice

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July 2007

Large area, >50%

Model Setup

RACM May 2010

Cordex domain50-km resF; FractionB; Binary

B

F/BB

Model Setup (cont…)

RACM May 2010

• Ensemble• Taschetto et al.• 8 members• BC:6-hr; 12-hr sea ice

• 2 treatments• fraction/binary

Simulations

RACM May 2010

• Init. ~1.5-2 weeks• May 24, 2007

• Target – June 6, 2007• sea-ice >50%

2-week Behavior

RACM May 2010

• Short-term• 2 weeks• May - June

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2-week Behavior (cont…)

F-BF-B(1-4)F-B(5-8)

MSLP

MSLP Avg.

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MSLP Avg. (cont…)

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MSLP Avg. (cont…)

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MSLP Avg. (cont…)

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MSLP Avg. (cont…)

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MSLP Avg. (cont…)

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MSLP Avg. (cont…)

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August

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October

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Aug/Oct Differences

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October 2m-T

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Concluding Remarks

RACM May 2010

• August differences• unforced bifurcation

• October differences• low-level T differences• occur along focus area• significant?

Questions

RACM May 2010

Daily Variance

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Daily Variance (cont…)

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ENS-Large

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ENS-Large (cont…)

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ENS-Large (cont…)

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ENS-Large (cont…)

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ENS-Large (cont…)

RACM May 2010