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Extreme Precipitation by High Resolution RegCM3

Extreme Precipitation by High Resolution RegCM3. Over East Asia. Jing ZHENG , Zhenghui Xie Institute of Atmospheric Physics (IAP),CAS, China Xunqiang Bi the Abdus Salam International Centre for Theretical Physics (ICTP), Italy. Outline. Introduction Model & Exp. Results

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Extreme Precipitation by High Resolution RegCM3

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  1. Extreme Precipitation by High Resolution RegCM3 Over East Asia Jing ZHENG , Zhenghui Xie Institute of Atmospheric Physics (IAP),CAS, China Xunqiang Bi the Abdus Salam International Centre for Theretical Physics (ICTP), Italy

  2. Outline • Introduction • Model & Exp. • Results • Discussion

  3. Outline • Introduction • Model & Exp. • Results • Discussion

  4. Giorgi & Bi, 2000: • The internal model variability exhibits a pronounced summer maximum. • It significantly influences the day-to-day model solution, especially for summer precipitation. • Also affected by the model internal variability was the frequency of occurrence of heavy daily precipitation events. • A regional climate model simulation is characterized by an intrinsic level of internal variability which can be excited by any type of perturbation and is regulated by synoptic conditions, season, model domain, region of application, and specific simulation period.

  5. Giorgi & Bi, 2000: • The internal model variability exhibits a pronounced summer maximum. • It significantly influences the day-to-day model solution, especially for summer precipitation. • Also affected by the model internal variability was the frequency of occurrence of heavy daily precipitation events. • A regional climate model simulation is characterized by an intrinsic level of internal variability which can be excited by any type of perturbation and is regulated by synoptic conditions, season, model domain, region of application, and specific simulation period.

  6. Resolution? • Model? Its internal model variability? 20km resolution of RegCM3 • the extreme precipitation,Yangzi and Huaihe Valley summer, 1998 • compared to 60km resolution & observational data. • the results indicated that high resolution can give more details about the region of the extreme precipitation. • Additionally, the maximum of the extreme precipitation were different by the two simulations of different resolutions. • Difficulties in simulating precipitation, esp. extreme prec.

  7. Outline • Introduction • Model & Exp. • Results • Discussion

  8. Dynamics: MM5 Hydrostatic (Grell et al 1994) Radiation: CCM3 (Kiehl 1996) Large-Scale Clouds & Precipitaion: SUBEX (Pal et al 2000) Cumulus convection: Anthes-Kuo (1977) Grell (1993) Emanuel (1991) Boundary Layer: Holtslag (1990) Tracers/Aerosols/dust: Qian et al (2001); Solmon et al (2005); Zakey et al. (2006) Land Surface: BATS (Dickinson et al 1993) SUB-BATS (Giorgi et al 2003) Ocean Fluxes BATS (Dickinson et al 1993) Zeng et al (1998) Computations Parallel Code (Bi, Gao, Yeh) Multiple Platforms More User-Friendly Code Summary of RegCM3 Core ICTP… (Pal et al 2006; Since Giorgi et al 1993ab)

  9. Experiment Design Region – East ChinaPeriod – 1998. Jun. ~ Aug. (June: Spinup time)Resolution – 2.5o60km20km (80*100, (32N,112E)) ICBC Experiment ERA40.vs.NNRP2Cumulus Scheme Experiment(ERA40)Domain Size experiment(NNRP2, icup=4)Buffer zone experiment(ERA40, icup=4)

  10. 60km 20km

  11. ? ICBC -- ERA40 .vs. NNRP2 ERA40 NNRP2

  12. Outline • Introduction • Model & Exp. • Results • Discussion

  13. Time Series for Precipitation • NNRP2 vs ERA40 (icup=4) 60km  20km • ERA40(icup=1,2,4)60km20km • 4 observational stations: • Wuhan, • Hefei, • Nanjing, • Shanghai

  14. ERA[i1] ERA[i2] ERA[i4] NNRP[i4] Ensemble Obs.

  15. ERA[i1] ERA[i2] ERA[i4] NNRP[i4] Ensemble Obs.

  16. ERA[i1] ERA[i2] ERA[i4] NNRP[i4] Ensemble Obs.

  17. ERA[i1] ERA[i2] ERA[i4] NNRP[i4] Ensemble Obs.

  18. Domain Size Experiment (NNRP2,i4) Large Small Obs

  19. Buffer Zone Experiment (ERA40,i4) BZ12 BZ18★ Obs

  20. Spatial pattern Met. stations RegCM3 CRU CMAP GPCP

  21. Spatial pattern tpr .vs. prcv July1998 ERA40_BZ ERA40_i4 NNRP2_i4 NNRP2_S

  22. Spatial pattern tpr .vs. prcv Aug1998 ERA40_BZ ERA40_i4 NNRP2_i4 NNRP2_S

  23. Outline • Introduction • Model & Exp. • Results • Discussion

  24. Preliminary conclusion & Discussion A CASE STUDY ---- • simulations were different by different resolutions/ domain sizes/ cumulus schemes/ forcing fields. • Resolution: higher resolution can give more details about the region of the extreme precipitation. • Domain: it depends, but smaller seems much higher peaks. • Cumulus schemes: MIT-Emanuel seems better here. • Forcing fields: ERA40 southward rain band [vs. NNRP2 ] • Difficulties in simulating precipitation, esp. extreme prec. • Resolution & Precipitation? • Cumulus scheme? Domain size? Forcing fields? • Internal model variability? • Land Component of the Model? More accurate physical process?

  25. Thanks for Your Attention!

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