Download - CGILS Updated Results
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,
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
GPCI
S6
S11 s12
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
(moist adiabat)
T(z)
RH Fixed
Warm Pool Cold 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
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.
Cloud feedbacks at S6
-20
-10
0
10
20
ca
m3
ca
m4
cs
iro
cs
iro
2
ec
mw
f
gfd
l
gis
s
gis
s2
gs
fc
kn
mi
larc
lmd
sa
m
sn
u
uk
mo
uk
mo
38
uk
mo
63
uw
m
CRF (W/m2)
s6
C
RF
(W
/m2
)
Cloud feedbacks at S6Round 1 versus Round 2
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
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
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
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)
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.
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
CAM4
CAM4 s6 ctl CAM4 s6 p2k
CAM4 s11 ctl CAM4 s11 p2k
CAM4 s12 ctl CAM4 s12 p2k
CAM4 ql s6 CAM4 ql s11 CAM4 ql s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
CAM5
CAM5 s6 ctl s6 p2k
s11 ctl s11 p2k
CAM5 s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
CCC
CCC s6 ctl s6 p2k
s11 ctl s11 p2k
CCC s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
ECHAM6
ECHAM6 s6 ctl s6 p2k
s11 ctl s11 p2k
ECHAM6 s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
ECMWF
ECMWF s6 ctl s6 p2k
s11 ctl s11 p2k
ECMWF s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
ECMWF2
ECMWF2 s6 ctl s6 p2k
s11 ctl s11 p2k
ECMWF2 s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
GISS
GISS s6 ctl s6 p2k
s11 ctl s11 p2k
GISS s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
GSFC
GSFC s6 ctl s6 p2k
s11 ctl s11 p2k
GSFC s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
JMA
JMA s6 ctl s6 p2k
s11 ctl s11 p2k
JMA s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
LMD
LMD s6 ctl s6 p2k
s11 ctl s11 p2k
LMD s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
RACMO
RACMO s6 ctl s6 p2k
s11 ctl s11 p2k
RACMO s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
UKMOL38
UKMOL38 s6 ctl s6 p2k
s11 ctl s11 p2k
UKMOL38 s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
CRF at S6
CRF at S11
CRF at S12
S6
S11
S12
UWM
UWM s6 ctl UWM s6 p2k
UWM s11 ctl UWM s11 p2k
UWM s12 ctl s12 p2k
ql at s6 ql at s11 ql at s12
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
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
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
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.
Summary
4.Comparisons with LES and with GCMs are yet to be carried out.