1. CGILS Updated Results GCSS-BLCWG Meeting, September 29-30, 2010 KNMI Minghua Zhang, Chris Bretherton, Peter Blossey Phil Austin, Julio Bacmeister, Sandrine Bony, Florent Brient, Anning Cheng, Stephan de Roode,Tony Del Genio, Charmaine Franklin, Chris Golaz, Cecile Hanny, Thijs Heus, Francesco Isotta, Dufresne Jean- Louis, In-Sik Kang, Hideaki Kawai, Martin Koehler, Suvarchal Kumar, Vince Larson, Adrian Lock, Ulrike Lohman, Marat Khairoutdinov, Andrea Molod, Roel Neggers, Sing-Bin Park, Irina Sandu, Ryan Senkbeil, Pier Siebesma, Colombe Siegenthaler-Le Drian, Bjorn Stevens, Max Suarez, Kuan-man Xu, Mark Webb, Audrey Wolfe, Ming Zhao,

2. SCM (16) CAM4* (Hannay, Zhang) CAM5* (Hannay, Zhang) CCC* (Austin) CSIRO* (Franklin) ECHAM5* (Siegenthaler-LeDrian, Lohman, Isotta) ECHAM6* (Kumar, Stevens) ECMWF* (Koehler) GFDL (Golaz, Zhao) GISS* (Wolfe, Del Genio) GSFC* (Molod, Bacmeister, Suarez) JMA* (Kawai) KNMI-RACMO* (Neggers) LMD* (Brient, Bony, Jean-Louis) SNU (Park, Kang) UKMO* (Webb, Lock) UWM* (Larson, Senkbeil) LES (5) DALES* (de Roode, Siebesma) SAM* (Blossey, Bretherton, Khairdinov) UCLA* (Heus, Sandu, Stevens) UCLA/LaRC* (Cheng, Xu) UKMO* (Lock) * Indicates models that carried out the revised runs

3. GPCI S6 S11 s12

4. Purpose: To understand the causes of cloud feedbacks, and thus climate sensitivities of climate models. Objectives: 1.To understand the physical mechanisms of cloud feedbacks in SCMs 2.To interpret GCM cloud feedbacks by using SCM results 3.To Evaluate the SCM cloud feedbacks using LES simulations

5. (moist adiabat) T(z) RH Fixed Warm PoolCold Tongue T(z) (Zhang and Bretherton, 2008) CGILS (CFMIP-GCSS Intercomparison of Large-Eddy and Single-Column Models) Need to be relevant to observations and GCMs

6. The second round of SCM simulations Forcing revised to be the same as in LES Control case temperature and relative humidity are now directly from ECMWF Interim Analysis for July 2003 from Martin Koehler. 1. Lower troposphere above the boundary layer is warmer, with more realistic inversion height and strength. 2. More moisture in the boundary layer for LES to start with. 3. Subsidence extended to below 1000 mb, thus slightly stronger than before below 900 mb.

7. Cloud feedbacks at S6

8. Round 1 versus Round 2

9.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12

10. Points to Note Some models maintain the same sign of feedbacks or negligible feedback at all three locations Negative feedback: CAM4, ECMWF, JMA, UWM Positive feedback: CAM5, CCC, CSIRO, ECHAM6, LMD, UKMO Flipped: GISS, GSFC, RACMO (in the same direction: positive at s6, negative at s12). Feedbacks at the two locations of S11 and S12 mostly show the same sign in the models

11.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12

12. Points to Note At S6, Two models show little feedback (CSIRO and UKMOL38) The small group show negative feedback (CAM4, ECMWF, JMA UWM) The majority show positive feedback (CAM5, CCC, ECHAM6, GISS, GSFC, LMD, RACMO) At S11, Two models show little feedback (ECHAM6 and LMD) About half of the models show positive feedback (CAM5, CCC, CSIRO, RACMO, UKMO) Half of the models show negative feedback (CAM4, ECMWF, GISS, GSFC, JMA, UWM) At S12, Two models show little feedback (ECHAM6 and LMD) Three models show positive feedback (CCC, CSIRO, UKMO) The majority show negative feedback (CAM4, CAM5, ECMWF, GISS, GSFC, JMA, RACOM,UWM)

13. Instead of discussing clouds at one location at a time (the GCSS perspective), in the following, we will show all cloud types for one model at a time (the GCM perspective) LES results are presented in Chris’s talk. This talk will only cover SCM results.

14.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 CAM4

15. CAM4 s6 ctl CAM4 s6 p2k CAM4 s11 ctlCAM4 s11 p2k

16. CAM4 s12 ctlCAM4 s12 p2k CAM4 ql s6 CAM4 ql s11CAM4 ql s12

17.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 CAM5

18. CAM5 s6 ctl s6 p2k s11 ctl s11 p2k

19. CAM5 s12 ctls12 p2k ql at s6 ql at s11ql at s12

20.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 CCC

21. CCC s6 ctl s6 p2k s11 ctl s11 p2k

22. CCC s12 ctls12 p2k ql at s6 ql at s11ql at s12

23.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 ECHAM6

24. ECHAM6 s6 ctl s6 p2k s11 ctl s11 p2k

25. ECHAM6 s12 ctls12 p2k ql at s6 ql at s11ql at s12

26.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 ECMWF

27. ECMWF s6 ctl s6 p2k s11 ctl s11 p2k

28. ECMWF s12 ctls12 p2k ql at s6 ql at s11ql at s12

29.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 ECMWF2

30. ECMWF2 s6 ctl s6 p2k s11 ctl s11 p2k

31. ECMWF2 s12 ctls12 p2k ql at s6 ql at s11ql at s12

32.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 GISS

33. GISS s6 ctl s6 p2k s11 ctls11 p2k

34. GISS s12 ctls12 p2k ql at s6 ql at s11ql at s12

35.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 GSFC

36. GSFC s6 ctl s6 p2k s11 ctl s11 p2k

37. GSFC s12 ctls12 p2k ql at s6 ql at s11ql at s12

38.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 JMA

39. JMA s6 ctl s6 p2k s11 ctl s11 p2k

40. JMA s12 ctls12 p2k ql at s6 ql at s11ql at s12

41.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 LMD

42. LMD s6 ctl s6 p2k s11 ctl s11 p2k

43. LMD s12 ctls12 p2k ql at s6 ql at s11ql at s12

44.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 RACMO

45. RACMO s6 ctl s6 p2k s11 ctl s11 p2k

46. RACMO s12 ctls12 p2k ql at s6 ql at s11ql at s12

47.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 UKMOL38

48. UKMOL38 s6 ctl s6 p2k s11 ctl s11 p2k

49. UKMOL38 s12 ctls12 p2k ql at s6 ql at s11ql at s12

50.  CRF at S6  CRF at S11  CRF at S12 S6 S11 S12 UWM

51. UWM s6 ctl UWM s6 p2k UWM s11 ctlUWM s11 p2k

52. UWM s12 ctls12 p2k ql at s6 ql at s11ql at s12

53. Negative feedbacks Deepened mixed layer without much dilution at the cloud top: 1.no explicit cloud-top entrainment and no shallow convection 2.weak cloud-top entrainment and small moisture effect of shallow convection 1000mb 900mb 950mb 800mb 1010mb

54. Negative feedbacks Deepened mixed layer without much dilution at the cloud top: 1.no explicit cloud-top entrainment and no shallow convection 2.weak cloud-top entrainment and small moisture effect of shallow convection 1000mb 900mb 950mb 800mb 1010mb

55. 1000mb 900mb 950mb 800mb 1010mb Positive feedbacks 1.More intermittent clouds due to cloud-top entrainment or shallow convection 2.Less cloud water due to large cloud-top mixing

56. Summary 1.Evidences suggest that the CGILS results from some models can be used to interpret GCM cloud feedbacks. For other models, especially those displaying multiple equilibrium behavior, alternative configuration of running the SCMs with representative transient forcing may be needed. This was demonstrated by the LMD group who added transient forcing to break up the multiple equilibriums. 2.Two groups of models have been identified to show the same sign or negligible cloud feedbacks at all three locations, displaying positive and negative feedbacks. It would be interesting to see if the corresponding GCMs show the same sign of cloud feedbacks. 3.The deciding physical process appears to be the mixing at the cloud top, carried out either by explicit cloud-top entrainment or shallow convection.

57. Summary 4.Comparisons with LES and with GCMs are yet to be carried out.