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Predicting the Earth System Across Scales: Both Ways. Greg Holland NCAR. Summary: Rationale Approach and Current Focus Improved Simulation of Tropical Modes Requirements for Tropical Cyclone Response to Climate Change. Rationale: Regional Climate. Downscaling Upscaling. 1995. - PowerPoint PPT Presentation
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Holland, CCSM Workshop 0606 ESSLESSL
Predicting the Earth System Across Scales: Both Ways
Predicting the Earth System Across Scales: Both Ways
Summary:Summary:
RationaleRationale
Approach and Current FocusApproach and Current Focus
Improved Simulation of Tropical ModesImproved Simulation of Tropical Modes
Requirements for Tropical Cyclone Response to Climate Requirements for Tropical Cyclone Response to Climate ChangeChange
Greg HollandGreg HollandNCARNCAR
Holland, CCSM Workshop 0606 ESSLESSL
Rationale: Regional ClimateRationale: Regional Climate
• Downscaling
• Upscaling
Holland, CCSM Workshop 0606 ESSLESSL
Downscaling and Upscaling: Atlantic Tropical Cyclone Trends
Downscaling and Upscaling: Atlantic Tropical Cyclone Trends
1900 1920 1940 1960 1980 2000 20200
5
10
15
20
25
30
Year
Tro
pic
al C
yclo
ne
Nu
mb
er
North Atlantic Tropical Cyclones 1905-2005
Individual Year
9-Year Running Mean1995
Satellites
Holland, CCSM Workshop 0606 ESSLESSL
Upscaling and Downscaling: Tropical Modes
Upscaling and Downscaling: Tropical Modes
ObservedObserved CCSMCCSM
All tropical modes are poorly handled by current climate All tropical modes are poorly handled by current climate models. This impacts everything from tropical cyclones to models. This impacts everything from tropical cyclones to ENSO and interactions with the extratropics.ENSO and interactions with the extratropics.
(Lin et al 2006)(Lin et al 2006)
Holland, CCSM Workshop 0606 ESSLESSL
The OpportunityThe Opportunity
WRF Community ModelCCSM/CAM Community Models
Holland, CCSM Workshop 0606 ESSLESSL
Approach and Current FocusApproach and Current Focus
Approach: Nesting the NCAR Weather Research and Forecasting Model into CAM as a 2-way Nested Regional Climate Model (NRCM);– Stage 1: Downscaling over North America (done);– Stage 2: 2-way atmospheric scale interactions in the
tropics (current);– Stage 3: NRCM in CAM/CCSM, with coupled ocean model;
as a community facility (next).
Current Focus: Tropical scale interactions:– Importance of mesoscale organization of convection
and its related surface exchanges and radiative influences for forcing tropical modes;
– Tropical mode forcing of tropical cyclone Tropical mode forcing of tropical cyclone development and intensification.development and intensification.
Holland, CCSM Workshop 0606 ESSLESSL
Model SetupModel Setup
Tropical Channel, 36 km, N/S boundaries 1-way nested into Tropical Channel, 36 km, N/S boundaries 1-way nested into NCEP Reanalysis with specified SST, Kain-Fritsch Cu NCEP Reanalysis with specified SST, Kain-Fritsch Cu Parameterization, CAM radiation and YSU boundary layer.Parameterization, CAM radiation and YSU boundary layer.
4 km nested domain inside 12 km 4 km nested domain inside 12 km and 36 km domains, fully 2-way and 36 km domains, fully 2-way interactive, Dudia cloud physics, interactive, Dudia cloud physics, CAM radiation and YSU boundary CAM radiation and YSU boundary layer.layer.Wind Speed (m/s)
Precipitable Water (mm)Precipitable Water (mm)
Holland, CCSM Workshop 0606 ESSLESSL
NRCM ExperimentsNRCM Experiments• CAM at T170 Resolution: Jan 1, 1966 to Jan 1 2001
• 36km Channel Model: Jan 1, 1996 to Jan 1, 2001
• 36km Channel + high resolution SST's: Jan 1, 1999 to Jan 1, 2000
• 36km Channel + fluxes: Jan 1, 1996 to Jan 1 1998 • 36km Channel + 12km Maritime domain: Jan 1, 1996 to Feb
12, 1998
• 36km Channel + 12/4km Maritime domains: Jan 1, 1997 to Jul 1, 1997
Holland, CCSM Workshop 0606 ESSLESSL
Power SpectraPower SpectraNCEP AnalysisNCEP Analysis
Improved Rossby Wave, Kelvin and MJO ModesImproved Rossby Wave, Kelvin and MJO ModesInertia-Gravity Inertia-Gravity Modes present, but Modes present, but too smalltoo small
NRCM SimulationNRCM Simulation
Holland, CCSM Workshop 0606 ESSLESSL
MJO and Easterly Wave Simulation MJO and Easterly Wave Simulation
Holland, CCSM Workshop 0606 ESSLESSL
July 22July 22ndnd over over eastern Indonesiaeastern Indonesia
August 19August 19thth in in eastern North eastern North PacificPacific
October 8October 8thth westerly wind westerly wind burstburst
MJO wet phaseMJO wet phase28 days28 days
39 days39 days
Holland, CCSM Workshop 0606 ESSLESSL
Easterly Wave Interactions with MJOEasterly Wave Interactions with MJO
0722:000722:00 0711:120711:12
0708:120708:12
0705:120705:12
0701:120701:12
0722:120722:12
0718:120718:12
0715:120715:12
Holland, CCSM Workshop 0606 ESSLESSL
NRCM Tropical Cyclone Simulation: Seasonal Distribution 1996-1998
NRCM Tropical Cyclone Simulation: Seasonal Distribution 1996-1998
-
1.0
2.0
3.0
4.0
5.0
6.0
1 2 3 4 5 6 7 8 9 10 11 12
Month
Nu
mb
er o
f T
Cs
SWP NRCM
SWP OBS
-
1.0
2.0
3.0
4.0
5.0
6.0
1 2 3 4 5 6 7 8 9 10 11 12
Month
Nu
mb
er o
f T
Cs
NIO NRCM
NIO OBS
-
1.0
2.0
3.0
4.0
5.0
6.0
1 2 3 4 5 6 7 8 9 10 11 12
Month
Nu
mb
er o
f T
Cs
ENP NRCM
ENP OBS
-
1.0
2.0
3.0
4.0
5.0
6.0
1 2 3 4 5 6 7 8 9 10 11 12
Month
Nu
mb
er o
f T
Cs
NAT NRCM
NAT OBS
-
1.0
2.0
3.0
4.0
5.0
6.0
1 2 3 4 5 6 7 8 9 10 11 12
Month
Num
ber o
f TCs
SIO NRCM
SIO OBS
ObservedSimulated
Holland, CCSM Workshop 0606 ESSLESSL
Annual Tropical Cyclone StatisticsAnnual Tropical Cyclone Statistics
0
5
10
15
20
25
30
35
SW
IO N
RC
M
SW
IO O
BS
Wau
s N
RC
M
Wau
s O
BS
SW
P N
RC
M
SW
P O
BS
NIO
NR
CM
NIO
OB
S
WN
P N
RC
M
WN
P O
BS
EN
P N
RC
M
EN
P O
BS
NA
T N
RC
M
NA
T O
BS
SWIO WAUS SWP NIO NWP ENP NAT
An
nu
al N
um
ber 19971997
0
5
10
15
20
25
30
35
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
SWIO WAUS SWP NIO NWP ENP NAT
An
nu
al N
um
ber
19961996
0
5
10
15
20
25
30
35
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
NR
CM
OB
S
SWIO WAUS SWP NIO NWP ENP NAT
An
nu
al N
um
ber
19981998Yellow are Observed; Blue are Simulated. Yellow are Observed; Blue are Simulated.
SWIO: Southwest Indian Ocean; SWIO: Southwest Indian Ocean; WAUS: Western Australia WAUS: Western Australia SWP: Southwest Pacific SWP: Southwest Pacific NIO: North Indian Ocean;NIO: North Indian Ocean; NWP: Northwest Pacific;NWP: Northwest Pacific; ENP: Eastern North Pacific;ENP: Eastern North Pacific; NAT: North Atlantic.NAT: North Atlantic.
Holland, CCSM Workshop 0606 ESSLESSL
Tropical Cyclones and Climate ChangeTropical Cyclones and Climate Change
1850 1900 1950 2000
-0.5
0
0.5
1
1.5
Year
EA
SS
T A
no
mal
y (C
)
1850 1900 1950 2000
0
5
10
15
20
25
30
Nu
mb
er o
f T
rop
ical
Cyc
lon
es
Holland, CCSM Workshop 0606 ESSLESSL
AEW DevelopmentAEW Development
1900 1920 1940 1960 1980 2000 202025.8
26
26.2
26.4
26.6
26.8
27
Year
SS
T (
C)
1900 1920 1940 1960 1980 2000 2020
2
3
4
5
6
7
8
Year
Nu
mb
er
of T
rop
ica
l Cyc
lon
es
Total Tropical Cycones vs East Atlantic SST
TC's Forming <20 Lat
Est Atlantic SST
R=0.659-y Running Mean
Holland, CCSM Workshop 0606 ESSLESSL
Importance of AEW DevelopmentImportance of AEW Development
0
1
2
3
4
5
6
0 10 20 30 40 50
Genesis Latitude
Ca
teg
ory
Equatorial90%
92%
81%
55%
36%
42%
(Data 1945-2004)
>85% of all Major Hurricanes develop from Easterly Waves!!!
Holland, CCSM Workshop 0606 ESSLESSL
East/West Atlantic and Gulf SSTsEast/West Atlantic and Gulf SSTs
(0.60)
(0.40)
(0.20)
-
0.20
0.40
0.60
1850 1900 1950 2000
EA 9-Y
WA 9-Y
GM 9-Y
Holland, CCSM Workshop 0606 ESSLESSL
Global Surface Temperature VariabilityGlobal Surface Temperature VariabilityVolcano
Ozone
Sulfate
Solar
There is no known natural forcing mechanism that can explain the surface temperature increases since 1960 (Meehl et al 2004, 2006)
Notice the warm 1940-50 period in the “natural cycle”
1970
(0.60)
(0.40)
(0.20)
-
0.20
0.40
0.60
1850 1900 1950 2000
Year
SS
T A
no
mal
y
EA 9-Y
EPAC 9-Y
The NAO
Holland, CCSM Workshop 0606 ESSLESSL
So what is happening?So what is happening?Compare the record 2005 season with a mean of 1991-1993:
• 2005: 27 Storms, 12 hurricanes, 5 cat 4-5;• 1991-1993: 22 storms (total), 12 hurricanes, 2 cat 4-5
• 2995 30% of all AEWs became named storms (normally 10%);
• AEWs produced 10 of the 14 hurricanes in 2005, all category 3-5 hurricanes, all tropical cyclones in July and August, and 8 of the 11 tropical cyclones in September and October. Two AEWs also generated two tropical cyclones each, a rare event that last occurred in 1988;
• For 1991-1993 only one hurricane developed from AEWs, there were no July storms and only one in October.
Holland, CCSM Workshop 0606 ESSLESSL
NAT SST-Hurricane RelationshipsNAT SST-Hurricane Relationships
Max SST
7000 km
Min OLR
North Atlantic oceanic and atmospheric response North Atlantic oceanic and atmospheric response to global warming.to global warming.
S S S 5 4 S 1 5 3 5 4 S S 2 1 S 3
Tropical cyclone formation locationsTropical cyclone formation locations
Holland, CCSM Workshop 0606 ESSLESSL
Vorticity Changes; du/dx<0Vorticity Changes; du/dx<0
July 2005July 2005
Holland, CCSM Workshop 0606 ESSLESSL
Assessing Potential Climate Change Impact on Tropical Cyclones:
Requirements
Assessing Potential Climate Change Impact on Tropical Cyclones:
Requirements
• Resolve hurricane structure• Simulate tropical atmospheric response to
oceanic heat changes• Simulate tropical modes accurately• Simulate feedback between hurricanes and
ocean/atmospheric circulations
Coupling CCSM/CAM with WRF and a GOM/ROM Coupling CCSM/CAM with WRF and a GOM/ROM
enables thisenables this
Holland, CCSM Workshop 0606 ESSLESSL
SummarySummary
• The weather and climate scales are part of a continuum of action across scales;
• We have the tools in CAM/CCSM and WRF to open up new frontiers in understanding and predicting these 2-way interactions;
• The Petascale Computing Facility provides the capacity;
So Lets Do ItSo Lets Do It
Thank YouThank You