1. The Seasonality and Partitioning of Atmospheric Heat Transport in a Myriad of Different Climate States
I. Introduction
II. A simple energy balance model for the seasonal cycle of energy fluxes
III. Dynamical heat transport partitioning
IV. Atmospheric heat transport in aquaplanet simulations
V. Atmospheric Heat Transport in Simulations with Land-Ocean Contrast and Topography
VI. Conclusions

2. a. The energy budget framework b. The dynamical framework
Introduction
a. The energy budget framework
b. The dynamical framework
II. A simple energy balance model for the seasonal cycle of energy fluxes
III. Dynamical heat transport partitioning
IV. Atmospheric heat transport in aquaplanet simulations
V. Atmospheric Heat Transport in Simulations with Land-Ocean Contrast and Topography
VI. Conclusions

3. I. Introduction / a. The energy budget framework
5.7 PW
5.9 PW
ERBE DATA

4. Zonal and Annual Averaged Energy Flux (global mean removed)
I. Introduction / a. The energy budget framework
Zonal and Annual Averaged Energy Flux (global mean removed)
ASR = Absorbed
solar
SHF = Surface
heat flux
(-)OLR = Outgoing
longwave
MHT = Meridional
Heat Transp.
CTEN = (-) Atmos
Column tendency
Observed NH
All signs defined wrt the atmosphere (e.g., negative OLR is an energy flux deficit for the atmosphere)
Surface heat flux = the total energy flux (radiative plus turbulent) through the surface/atmosphere interface
In the annual mean, positive SHF is equal to oceanic heat flux convergence
ERBE/
NCEP

5. I. Introduction / a. The energy budget framework
Annual mean of energy budget poleward of 300N (Departures from global annual mean)
2.2 PW
4.3 PW
1.4 PW
Tropics
North Polar
Region
Absorbed
Solar (ASR)
7.9 PW
Surface Heat
Flux (SHF)
Negative
OLR
Meridional
Heat Transport
(MHT)

6. I. Introduction / a. The energy budget framework
Zonal and Seasonal Averaged Energy Flux (zonal, annual average removed)
ASR
SHF
MHT
Observed NH
(-) OLR
CTEN
(-) Atmospheric Column
tendency
ERBE/NCEP
DATA

7. Seasonal Extratropical Energy Budget
I. Introduction / a. The energy budget framework
Seasonal Extratropical Energy Budget

8. I. Introduction / b. The dynamical framework
Transient Eddies (Storm Tracks)
Mean Meridional
Circulations (MMC)
Heat Transport
W/m
STATIONARY WAVES
Temp.
Anom.
(K)
Meridional Wind Anomaly

9. I. Introduction / b. The dynamical framework
Partitioning of heat transport from NCEP reanalysis PW PW PW PW

10. I. Introduction / b. The dynamical framework
Heat transport partitioning at latitude of maximum heat transport

11. Introduction
II. A simple energy balance model for the seasonal cycle of energy fluxes
III. Dynamical heat transport partitioning
IV. Atmospheric heat transport in aquaplanet simulations
V. Atmospheric Heat Transport in Simulations with Land-Ocean Contrast and Topography
VI. Conclusions

12. II. A simple energy balance model for the seasonal
cycle of energy fluxes
OLR’ = BOLR T’A,E
ASR’
T’A,E
T’A,T
BCTENTA,E
MHT’ = BMHT(T’A,T – T’A,E)
TS’ BOCE
TROPICS
EXTRATROPICS
Primes denote anomaly from global annual mean

13. Annual mean extratropical energy balance
II. A simple energy balance model for the seasonal
cycle of energy fluxes
Annual mean extratropical energy balance
Global mean energy balance requires:
OLR’ = 0 or T’T = - T’E = ΔT
ASR’ ΔT
OLR’
-ΔT
MHT’
TROPICS
EXTRATROPICS
MHT = BMHT2ΔT
OLR’ = BOLRΔT
MHT / OLR = 2BMHT/BOLR = 2.3
Real world ratio is 2.6 (including ocean); we shouldn’t be surprised

14. II. A simple energy balance model for the seasonal
cycle of energy fluxes
Seasonal cycle of extratropical energy fluxes
Asterisks =
AGCM simulation
Solid = EBM
Dotted = theory
Based on “B”
coefficients
The seasonal amplitude of extratropical energy fluxes is partitioned into ocean storage (SHF), heat transport (MHT), OLR, and atmospheric storage (CTEN) in the approximate ratio:
lSHF’l : lMHT’l : lOLR’l : lCTEN’l ≈
BOCE : BMHT:BOLR : BCTEN

15. III. Dynamical heat transport partitioning
I. Introduction
II. A simple energy balance model for the seasonal cycle of energy fluxes
III. Dynamical heat transport partitioning
a. Methodology
b. Spatial and Temporal patterns of variability
IV. Atmospheric heat transport in aquaplanet simulations
V. Atmospheric Heat Transport in Simulations with Land-Ocean Contrast and Topography
VI. Conclusions

16. III. Dynamical heat transport partitioning
b. Spatial and Temporal patterns of variability
ANNUAL MEAN VERTICALLY INTEGRATED HEAT TRANSPORT
Transient Eddies
Stationary Eddies PW
SEASONAL REGRESSION MAP VERTICALLY INTEGRATED HEAT TRANSPORT
Transient Eddies
Stationary Eddies PW
Units are PW, if the local heat flux existed at all zonal locations
Seasonal regression takes the zonal mean transient or stationary eddy time series at the latitude of maximum heat transport and regresses it against the spatial map
OTHER ANAYLSIS- seasonal eofs, inter-annual eofs, interannual variability

17. IV. Atmospheric heat transport in aquaplanet simulations
I. Introduction
II. A simple energy balance model for the seasonal cycle of energy fluxes
III. Dynamical heat transport partitioning
IV. Atmospheric heat transport in aquaplanet simulations
a. Ocean mixed layer depth experiments
b. Longwave emissivity (CO2) experiments
c. Planetary rotation rate experiments
V. Atmospheric Heat Transport in Simulations with Land-Ocean Contrast and Topography
VI. Conclusions

18. IV. Aquaplanet simulations
a. Ocean mixed layer depth experiments
METHOD: GFDL 2.1 atmosphere (seasonal insolation) coupled to a slab ocean
- Vary mixed ocean depth (Dargan)
HYPOTHESIS: Annual mean is unaffected, as the ocean depth increase more seasonal energy goes into ocean storage and the seasonal amplitude of MHT, OLR, and CTEN decrease
Asterisks =
AGCM simulation
Lines = EBM
simulations
Dotted Lines =
B pseudo-steady
state theory
Donohoe and
Battisti 2010

19. IV. Aquaplanet simulations
b. Longwave emissivity (CO2) experiments
METHOD: Vary CO2 from LGM (180 ppm) to 4 times PI (1280ppm) [Dargan]
HYPOTHESIS: - The efficiency of energy export by longwave radiation (BOLR) goes down, in the annual mean and seasonal cycle the ratio of MHT to OLR decreases (infrared opacity)
- The efficiency of MHT (BMHT) increases in a warmer world (more moist transport)

20. IV. Aquaplanet simulations
b. Longwave emissivity (CO2) experiments
Annual Mean Heat Transport
Heat Transport (PW)
Latitude
QUAD PI
180 ppm

21. IV. Aquaplanet simulations
c. Planetary Rotation Rates
METHOD: Vary Earth’s rotation rate from 0.5X to 2.0X the current rotation rate
HYPOTHESIS: With a faster rotation rate, the eddy length scale and efficiency of meridional heat transport (BMHT) will decrease- less heat transport and larger temperature gradient
EDDY HEAT TRANSPORT AS A FUNCTION OF Ω
[Perpetual Annual Mean Insolation, Realistic Topography]
Dry Transient
Eddy Heat
Transport (1014 W)
0.25 Ω
1.0 Ω
(Del Genio and
Suozzo 1986)
Latitude

22. I. Introduction
II. A simple energy balance model for the seasonal cycle of energy fluxes
III. Dynamical heat transport partitioning
IV. Atmospheric heat transport in aquaplanet simulations
V. Atmospheric Heat Transport in Simulations with Land-Ocean Contrast and Topography
a. Land fraction experiments
b. Topography experiments
c. The full gauntlet (realistic climate states)
VI. Conclusions

23. V. Land-Ocean Contrast and Topography
a. Land Fraction Experiments
METHOD: A single extratropical continent with North-South Coastlines and varying zonal width – NO TOPOGRAPHY
HYPOTHESIS: - ENERGETICS: As land mass increases, more seasonal energy goes into the atmosphere, and the seasonal cycle of heat transport increases
- DYNAMICS: Zonal heating anomalies induce stationary waves, heat transport partitioning changes, total heat transport (BMHT)?
Solid = EBM simulations
Dashed = Pseudo-steady
state theory

24. V. Land-Ocean Contrast and Topography
b. Topography experiments --- IDEALIZED
METHOD: Aquaplanet with a single idealized mid-latitude topographic feature of
varying height, meridional location, and zonal width
HYPOTHESIS: - Topography induces stationary wave heat transport
- Storm tracks become localized, transient eddy heat transport goes down (seeding?)
-Partitioning will change, TOTAL HEAT TRANSPORT?
Dry model, T21
Newtonian cooling to equilibrium temperature
Eddy Heat Transport (K m/s)
Equivalently = 0.25 PW
(Yu and Hartmann, 1995)
Mountain Height (km)

25. V. Land-Ocean Contrast and Topography
b. Topography experiments --- Realistic topography
METHOD: Aquaplanet with flat topography, present day topography, and LGM topography (ICE – 5G, Peltier )
HYPOTHESIS: The partitioning between transient and stationary eddies will change– total heat transport?
Stationary Eddy DRY Heat Transport
Transient Eddy DRY Heat Transport 50 50
LGM
-50
-50
Jan Apr Jul Oct
Jan Apr Jul Oct 50 50
MODERN
Latitude
-50
-50
Jan Apr Jul Oct
Jan Apr Jul Oct 50 50
MOD - LGM PW PW
-50 -2
-50 2 -1 1
Jan Apr Jul Oct
Jan Apr Jul Oct

26. V. Land-Ocean Contrast and Topography
c. The Full Gauntlet (Realistic Climate States)
Method: AGCM (CAM3) simulations of LGM, PI, 4XCO2 forced by
prescribed SST and sea ice (from CCSM coupled runs), land ice
topography, greenhouse gases, and solar insolation
Hypothesis: (almost) Everything we’ve learned becomes important:
1. CO2 experiments
2. Land Fraction Experiments (sea ice is like land)
3. Topography
4. Additionally, the absorbed solar radiation changes,
we’ll treat this as a forcing
(CAMILLE LI)

27. V. Land-Ocean Contrast and Topography
c. The Full Gauntlet (Realistic Climate States)

28. VI. Conclusions I. Introduction
II. A simple energy balance model for the seasonal cycle of energy fluxes
III. Dynamical heat transport partitioning
IV. Atmospheric heat transport in aquaplanet simulations
V. Atmospheric Heat Transport in Simulations with Land-Ocean Contrast and Topography
VI. Conclusions

29. QUESTIONS ?