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WG 4 CORSO

WG 4 CORSO. Data assimilation system based on nudging for COSMO-Ru7/So2. Denis Blinov, G. Rivin, M. Nikitin, A. Bundel, A. Kirsanov, I. Rozinkina. Outline. Initial conditions (IC) in operative Cosmo-Ru system Errors IC Data Assimilation System (DAS) based on nudging

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WG 4 CORSO

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  1. WG 4 CORSO Data assimilation system based on nudging for COSMO-Ru7/So2 Denis Blinov, G. Rivin, M. Nikitin, A. Bundel, A. Kirsanov, I. Rozinkina COSMO GM Sibiu, 2 - 5 Sept. 2013

  2. Outline • Initial conditions (IC)in operative Cosmo-Ru system • Errors IC • Data Assimilation System (DAS) based on nudging • Estimation experiments with DAS • Conclusions and outlook COSMO GM Sibiu, 2 - 5 Sept. 2013

  3. Initial conditionsin Cosmo-Ru • In the current operational scheme initial data are prepared from the interpolated data GME (h=20 km); • Initial conditions are concluded • atmospherefields (U, V, P, W, T, QV), • surface fields (T_S, T_SNOW, T_ICE, H_ICE, T_SO, W_SO) • external parameters. COSMO GM Sibiu, 2 - 5 Sept. 2013

  4. Errors of initial conditions • For the entire domain COSMO there are significant errors in the field T_2m at the beginning of the forecast; • It is supposed that errors in the initial data associated with all 3 types of fields: external parameters, atmospheric and surface fields. COSMO GM Sibiu, 2 - 5 Sept. 2013

  5. Errors T_2m in COSMO-So2 (Adler-cluster)for winter 2011/2012 (left) and 2012/2013 (right)for 00, 06, 12, 18 runs Errors of initial conditions ME RMSE

  6. DA system • Through the assimilation, we were trying to reduce the errors in the atmospheric fields • DAS uses observations SYNOP, TEMP, SHIP, BUOY, AIREP • The scheme Nudging in Cosmo is correctingatmosphere fieldsT, PS, H, QV, U, V • On first step DAS is based on 6 hour cycle - Main Run (MR) • On the next step DAS will included on continuous cycle - Recalculate Run (RR) COSMO GM Sibiu, 2 - 5 Sept. 2013

  7. Scheme of assimilation system COSMO GM Sibiu, 2 - 5 Sept. 2013

  8. The old(left) and new parallel(right) operational scheme COSMO-RU07 и COSMO-RU02 COSMO GM Sibiu, 2 - 5 Sept. 2013

  9. Model grids and used observations The number of grid points of the model ETR7 more than stations in ~1600 for the temperature and ~32000 for SFO2. Not enough of upper-air stations for successfully correcting temperature. You must use t_2m observation from SYNOP. COSMO GM Sibiu, 2 - 5 Sept. 2013

  10. Experiments Experiments for COSMO-Ru7 with: IC from DAS IC from GME List verification stations: EPR887 – 887 stations on entire domain COSMO-Ru7 EPR293 – 293 stations on entire domain COSMO-Ru7 SFO – 145 stations on South Federal District CFO – 220 stations on Central Federal District … Period testing: February 2012 July 2012 December 2012 COSMO GM Sibiu, 2 - 5 Sept. 2013

  11. Mean error (ME)T_2m forEPR887 1-10 December 2012 COSMO GM Sibiu, 2 - 5 Sept. 2013

  12. Mean errorT_2m forSFO 1-10 December 2012 COSMO GM Sibiu, 2 - 5 Sept. 2013

  13. ErrorsT_2m forinitial time andforecast on 6 hours • Found the understatement of the amplitude for all terms and for all seasons; • The daytime temperature is underestimated, night overstated, morning and evening errors are minimal; • On the chart of errors at the beginning of the forecast is observed local extremum. We believe that this effect is connected with interpolation from coarse grid (spinup); • Very significant differences between the terms.On a 12-h forecast error temperature is minimal. COSMO GM Sibiu, 2 - 5 Sept. 2013

  14. Mean Error for T_2m ref - experiment with initial conditions from GME das - experiment with initial conditions from Data Assimilation System COSMO GM Sibiu, 2 - 5 Sept. 2013

  15. Experiments with DWD assimilation for COSMO-Ru domain, February 2012, EPR293 COSMO GM Sibiu, 2 - 5 Sept. 2013

  16. Experiments with DWD assimilation for COSMO-Ru domain, February 2012, SFO ME RMSE COSMO GM Sibiu, 2 - 5 Sept. 2013

  17. Results testing DAS for field T_2m • Assimilation helps to improve the temperature field during the early stages in the case of large errors in GME fields; • When errors GME are minimal assimilation brings errors from 6-hour lead time. In some cases, it worsens the initial field - forecasts from 12 UTC; • Mainly ME better on 0.3 degree for DAS; • It is necessary to correct/change the temperature of the soil, snow, sea for Continuous Cycle. COSMO GM Sibiu, 2 - 5 Sept. 2013

  18. ME, RMSET_2m forEPR887 1-10 December 2012 COSMO GM Sibiu, 2 - 5 Sept. 2013

  19. ME, RMSETd_2m forEPR887 1-10 December 2012 COSMO GM Sibiu, 2 - 5 Sept. 2013

  20. Mean error, RMSEPMSL forEPR887 1-10 December 2012 COSMO GM Sibiu, 2 - 5 Sept. 2013

  21. Mean error, RMSEwind speed 10m forEPR887 1-10 December 2012 COSMO GM Sibiu, 2 - 5 Sept. 2013

  22. Conclusions • Mainly effect of “spinup” at the beginning of the forecast disappears; • Fields T_2m, Td_2m, PSML, Wind Speed 10m is better with DAS in 0-3 hours forecast time; • When errors GME are minimal assimilation brings errors from 6-hour lead time. In some cases, it worsens the initial field - for example forecasts from 12 UTC; • It is necessary to correct/change the temperature of the soil, snow, sea for Continuous Cycle; • It is necessary to use more observations. COSMO GM Sibiu, 2 - 5 Sept. 2013

  23. Outlook • Correct surface field: • T_Soil, T_air (correction module by Sapuntsova) • T_S via Flake • Increase count of data in DAS: • feedback-file • AMS • Radar data (Latent Heat Nudging) • Testing continuous cycle for COSMO-So2 km COSMO GM Sibiu, 2 - 5 Sept. 2013

  24. Experiments with module correction T_SO, T_air by Sapuntsova Verification for 18 February 2012 COSMO GM Sibiu, 2 - 5 Sept. 2013

  25. Experiments with module correction T_SO, T_air by Sapuntsova RMSE t_2m for February 2012 COSMO GM Sibiu, 2 - 5 Sept. 2013

  26. Thank you for attention!Questions?Remark? COSMO GM Sibiu, 2 - 5 Sept. 2013

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