Download Important data of cloud properties for assessing the response of

Important data of cloud
properties for assessing the
response of GCM clouds in
climate change simulations
Yoko Tsushima
JAMSTEC/Frontier Research
Center for Global Change
Contents
• Cloud feedback uncertainty in GCM global
warming simulations
– Uncertainty in the tropics
– Uncertainty in the mid-high latitudes
• “Toward fusion of satellite observation and ultrahigh resolution modeling” : Global cloud
resolving model NICAM
– Data
– Workshop announcement: 3rd-5th, Oct, Kusatsu,
Japan
Cloud feedback in the tropics
15 AR4 coupled ocean-atmosphere GCMs
+1%/yr CO2:
Sensitivity of the tropical NET CRF to
long-term SST changes (W/m2/K)
(low-sensitivity
models)
(high-sensitivity
models)
The cooling effect
of clouds is reduced
(enhances
climate sensitivity)
The cooling effect
of clouds is enhanced
(decreases
climate sensitivity)
Bony and Dufresne, GRL (2005)
ISCCP cloud amounts and ERA40 500mb
(tropical oceans, 1984-2000)
Low-level cloud tops
Upper-level cloud tops
+1%/yr CO2 :
Convective
regimes
Sensitivity of the tropical CRF
to long-term SST changes in
global warming experiments
CRF
SST
(W/m2/K)
2 OAGCM groups:
High-Sensitivity models 0)
Low-Sensitivity models 0)
HS GCMs
LS GCMs
HS GCMs
LS GCMs
HS GCMs
LS GCMs
Subsidence
regimes
Interannual Climate Variations
(an example, not an analogue!)
Sensitivity of the SW CRF to SST changes
composited by dynamical regimes
convective regimes
OBS
1984-2000 monthly data :
• ISCCP-FD radiative fluxes
• Reynolds SST
• ERA40 or NCEP2 reanalyses
AR4 OAGCMs:
•20th century simulations
• HS (N=8) vs LS (N=7) models
High-Sensitivity models
Low-Sensitivity models
subsidence
It is in regimes of large-scale subsidence (associated with low-level clouds)
that the relationship between cloud radiative forcing and SST :
(1) Differs the most among models in climate change
(explains most of inter-model differences in cloud feedbacks)
(2) Disagrees the most with observations in current interannual
climate variability (models underestimate the sensitivity of clouds
albedo to a change in SST)
The simulation of marine boundary-layer clouds is at the heart
of tropical cloud feedback uncertainties in AR4 models.
Any impact on the simulation of ENSO variability ??
Needs some investigation..
Change in Cloud water:
feedback in the mid and high
latitudes
Cloud Feedback Model
Intercomparison Project (CFMIP)
McAvaney and Le Treut (2003)
• Outputs from IPCC models with more cloud
variables than IPCC outputs.
• Slab ocen experiments with 1xCO2, 2xCO2.
• Webb et al.,2006
– The intermodel range in net cloud feedback is larger
than the associated clear-sky response range: the
differences in cloud response make the largest
contribution to the range in climate sensitivity.
Tsushima et al., 2006
Cloud ice (1xCO2) Cloud liquid(2xCO2－1xCO2)
Cloud water (1xCO2)
[hPa]
6.3℃
Climate sensitivity
4.0℃
3.6℃
2.9℃
2.3℃
[hPa]
[hPa]
0
0
0
200
200
200
400
400
400
600
600
600
800
800
800
1000
1000
1000
0
0
0
200
200
200
400
400
400
600
600
600
800
800
800
1000
1000
1000
0
0
0
200
200
200
400
400
400
600
600
600
800
800
800
1000
1000
1000
0
0
0
200
200
200
400
400
400
600
600
600
800
800
800
1000
1000
1000
0
0
0
200
200
200
400
400
400
600
600
600
800
800
800
1000
1000
－90 －60 －30 0
0
1.5e-4
30
60
1000
－90 －60 －30 0
90
0
2.5e-5
30
60
90
－90 －60 －30 0
-2e-5
0
2e-5
30
60
90
Zonal mean profile of relative humidity, cloud water,
cloud ice under 1xCO2 climate in [60S:30S]
Relative humidity
Cloud water
Cloud ice
Implications from multi-GCM
analysis
Assessment of the mean state and
sensitivity of
• Low clouds in the large scale subsidence
region
• Mixed-phase level clouds (which is
dominant clouds in the extra-tropics)
using observational data
are important for assessing GCM clouds.
“Toward fusion of satellite
observation and ultra-high
resolution modeling” : Global cloud
resolving model NICAM
Outlines
Global Cloud Resolving Model
NICAM (Nonhydrostatic ICosahedral Atmospheric Model)
•
•
•
•
Icosahedral grid & Nonhydrostatic model & Explicit cloud physics
Development since 2000: number of test cases
Problems of Current GCMs:Δx~ 20km at best & hydrostatic, cloud parameterization
Horizontal resolution: up to dx=3.5km
Global cloud resolving simulations with NICAM
 3.5km-mesh Aqua Planet Experiment
 GCM expemeriments with realistic land/sea disribution
• 30days run through Apr. 2004
• preliminary results with 14km-mesh
Icosahedral grids
Original Icosahedron
Glevel-0
Glevel-9: Δx=14km
Glevel-10: Δx=7km
Glevel-11: Δx=3.5km
Glevel-1
Glevel-3
Glevel-5
Condensed water distribution in Aqua planet experiment
condensed water
cloud liquid
cloud ice
snow
rain
Tsushima, 2006
 What are the definition of “cloud liquid”, “rain”, “cloud
ice”and “snow”? Usage of observational definition is
useful.
 “Total condensed water” data are also informative.
Preliminary results of
a global cloud-resolving simulation
with realistic topography
•dx=14km (glevel9) L40 without parameterization
•dx=7, 3.5km, on going
•Apr. 2004, short-term (H.Miura)
•Perpetual July experiment, statistics (S.Iga)
Apr. 2004 short term exp.
Initial condition: 2004/04/01 0UTC, 30 days simulation with 14km-mesh
2004/04/05 00UTC
NICAM 14km
GMS/GOES
2004/04/02 00UTC
2004/04/03 00UTC
2004/04/04 00UTC
GOES-9 Kochi-Univ.(http://weather.is.kochi-u.ac.jp/)
NICAM gl-09
2004/04/05 00UTC
2004/04/06 00UTC
2004/04/07 00UTC
2004/04/08 00UTC
2004/04/09 00UTC
2004/04/10 00UTC
Precipitation statics comparison between global cloud resolving simulation
with NICAM and TRMM PR data
Satoh et al.,2006
Data Summary
A global cloud resolving model (GCRM)
Nonhydrostatic system & Icosahedral grid: NICAM
avoid ambiguity of cumulus parameterizations
Use of the Earth Simulator
An aqua-planet-experiment dx=3.5km and 54 layers
Hierarchical structure of cloud convection
Moist Kelvin wave structure with realistic phase speed
Internal motions including wave structure
Nasuno et al.(2006,submitted to JAS)
GCRM runs on the realistic land-ocean distribution
dx=14km, 30days done: dx=7, 3.5km, on-going
 Apr. 2004, short-term (H.Miura)
 Perpetual July experiment, statistics (S.Iga)
Announcement of a Workshop
High resolution & cloud modeling workshop
“toward fusion of satellite observation and ultra-high
resolution modeling”
3rd-5th, Oct, Kusatsu, Japan
If you are interested in the data and/or the workshop,
please contact me!
Thank you.
Yoko Tsushima
E-mail: [email protected]
Frontier Research Center for Global Change/JAMSTEC
Japan