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National Ice Center Science and Applied Technology Program

The National Ice Center Science and Applied Technology Program is focused on developing nowcast and forecast products for global and regional sea ice conditions. Dr. Michael Van Woert is the Chief Scientist leading the program. The program includes the development of global and regional nowcast products, as well as planned global and regional forecast products. The program also involves the validation and improvement of sea ice models and data assimilation techniques. The ultimate goal is to provide accurate and reliable sea ice information for operational and scientific purposes.

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National Ice Center Science and Applied Technology Program

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  1. National Ice CenterScience and Applied Technology Program Dr. Michael Van Woert, Chief Scientist

  2. weekly global manual Planned Nowcast Product Evolution: “NIC 5 Year Plan” GLOBAL NOWCAST PRODUCT CURRENT PRODUCT daily global Science makes the next step to NOWCAST products possible. model / assimilation-based low resolution (10 km) REGIONAL NOWCAST PRODUCT daily non-global manual, some automation high resolution (<1km)

  3. regional manual heuristic Planned Forecast Product Evolution: “NIC 10 Year Plan” PLANNED GLOBAL FORECAST PRODUCT CURRENT FORECAST PRODUCT Short-term (24-120 Hours) Global Science makes the next step to FORECAST products possible. Coupled Dynamical Model Data Assimilation Support PLANNED REGIONAL FORECAST PRODUCT Seasonal (30, 90 day) Non-global Statistical Model Climate Indices

  4. PIPS 2.0 Ocean/Ice Model Coupled Ice-Ocean Model (Hibler/Cox) 0.28 degree grid resolution (17-34 km) 15 vertical levels Solid wall boundaries Ocean loosely constrained to Levitus climatology Forced by NOGAPS Initialized with SSM/I PIPS 2.0 domain. Hatched lines drawn every 4th grid point

  5. Forecast Skill Scores #1 Af= accuracy of the forecast system Ap= accuracy of a perfect forecast Ar= accuracy of a reference forecast In this formulation SS represents the improvement in accuracy of the forecasts over the reference forecasts relative to the total improvement in accuracy.

  6. Forecast Skill Scores #2 Accuracy defined as:

  7. Forecast Skill Scores #3 SS>0 (skillful) when MSE(R,O) > MSE(f,O). SS<0 (unskillful) when MSE(R,O) <MSE(f,O) Perfect forecast SS=1; MSE(f,O)=0 No forecast skill SS=0; MSE(f,O)=MSE(R,O)

  8. PIPS 24-Hour Forecast Validation PIPS much better than climo But with respect to persistence?

  9. For More Info See also – M. Van Woert et al., “Satellite validation of the May 2000 sea ice concentration fields from the Polar Ice Prediction System”, Canadian Journal of Remote Sensing, 443-456, 2001

  10. Product Resolution Precision Tolerances Range Ice Concen. 10 km +/- .5 Tenths 0-10/10ths Ice Thickness 10 km Flag Old Ice (2nd Year and Multiyear +/- 25% Non-Multiyear Ice 0-5 meters Ice Drift (Speed) 10 km (< 10cm/sec) +/- 5cm (>10cm/sec) +/- 20% 0 – 100 km day-1 Ice Drift(Direction) 10 km +/- 20% 360 Deg Ice Edge 10 km +/- 10 km N/A Ice Deformation 10 km +/- 25% of Range +/-5X10-8 sec-1 Fracture (Lead) Orientation 100 km2 +/- 45o 360 deg NIC Forecast Requirements

  11. Navy ice modeling effort to use Los Alamos C-ICE model for operational sea ice analysis and forecasting • Plan to couple to Global NCOM Ocean Model • Provide end-user guidance to Technical Validation Panel Polar Ice Prediction System 3.0

  12. National Weather Service Support Daily weather in the United States is strongly linked to Arctic sea ice conditions. ice free Sea Ice http://science.natice.noaa.gov/work/ice_con_test.grb

  13. MIZ Model 1 • Marginal Ice Zone Model (Maksym - now at USNA) • Thermodynamics model driven by SSM/I data • Validation data obtained on Healy cruise Ice core thick section from Healy 1 With Coon and Toudal

  14. The Model • Free Drift • 3% of the wind speed • 23° to the right of the wind • Conserve Ice • Single ice thickness category • 2nd upwind difference scheme • Mass conserving • NASA TEAM Sea Ice • EASE, equal area grid • 25 km resolution, daily • 435 x 435 elements ~70,000 O & I • Force with ECMWF wind • 12 hour time step • Interpolated to SSM/I grid: d-2 for for for for Model of c(t) written as a 2-d matrix, A(t) Dimensions ~70,000 x 70,000 – mostly zeros!

  15. Kalman Filter #1 Forecast step: C is the prior estimate of the sea ice concentration field (~7,000 elements) Cf is the forecasted sea ice concentration field P is the prior estimate of the covariance (~7,000 x 7,000) Pf is the forecasted covariance function A is the matrix of model coefficients and AT is its transpose (~7,000 x 7,000) ~ indicates that the value is an estimate C(0) is the NASA Team sea ice data for December 31, 2001 [ y(0) ] P(0) is assumed diagonal and equal to 5% ~

  16. Kalman Filter #2 Correction Step: K is the Kalman gain E is the observation design matrix (1’s on the diagonal) y is the SSM/I sea ice concentration data vector R is the noise covariance for the SSM/I data (assumed diagonal and 5%)

  17. Kalman Filter #3 • Assume single observation • Assume E=1 For R 0 (perfect obs), K 1 and cy (obs) For R inf (bad obs), K  0 and c  cf (model)

  18. Preliminary Results Initial Field December 31, 2001 Forecast January 04, 2002 Observed January 04, 2002 White indicates ice concentration >100% (i.e. thickness changes) 2 hours per day – 2.7 GHz PC, 512 meg, Windows XP, M/S 4.0

  19. Not Yet Completed • Careful analysis and selection of P(t=0) • Careful analysis and selection of R(t=0) • Display and analysis of P(t) • Inclusion of controls in the Kalman Filter • Examination of forecast skill • Include an ice thickness equation • Improve satellite-derived sea ice data products • Incorporate data assimilation of sea ice motion

  20. WindSat/Coriolis Mission Passive Polarimetric Microwave Radiometer - Frequencies 6.8 GHz V, H 10.0 GHz V, H, U, V 18.7 GHz V, H, U, V 22 GHz H 37 GHz V, H, U, V - Launch Jan 2003 - Naval Res. Lab. - Measure Wind Speed & Dir! - What about sea ice??? Work toward improved ice typing with QuikScat/Windsat: K. Partington, N. Walker, S. Nghiem, M. Van Woert

  21. 50 cm s-1 Buoys Sea Ice Data Assimilation SSM/I Motion OI Motion 50 cm s-1 19-Jan-92 Model Motion • SSM/I • Many missing vectors • Noisy • Model • Often wrong • Objective Interpolation • Constrains model • Interpolates between data • Kalman Filter • Moving in that direction 50 cm s-1 Meier, Unpublished

  22. Satellite-Derived Ice Motion • Scatterometer data and radiometer data complement each other in estimating ice motion • Where radiometer has difficulties, scatterometer does well and visa versa • Enables complete coverage motion maps Meier, unpublished

  23. Riverdance ends its Arctic run … minus the usual encore.

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