Did the Sunspot Cycle Cause the Fall of the Ming Dynasty? Yuk Ling Yung CUHK 25 Oct 2004.

Did the Sunspot Cycle Cause the Fall of the Ming Dynasty?

Yuk Ling Yung

http://www.gps.caltech.edu/faculty/yung

CUHK 25 Oct 2004

1644. 3. 291944. 3. 29

49

52

68 100

Kiehl and Trenberth 1997

Top-of-atmosphere

Surface

Top-of-atmosphere

Surface

Net DifferencesShortwave

Radiation TOA

Quite strong structure due to clouds in ASR and OLR that mostly cancels in the net; some other albedo effects (e.g., Sahara) and land-sea differences, but sun-Earth geometry explains most of pattern.

ASR

OLR

NET

Trenberth and Stepaniak, J. Clim. 2003

George Hadley (1685-1768), English lawyer and scientist.“I think the cause of the general Trade-winds have not been explained by any of those who have wrote on that subject” (1735)

The overturning Hadley cells are the main way the atmosphere transports energy polewards in low latitudes

NetRadiation TOA

Total heating Q1-Q2

Difference due to ocean transports

Trenberth & Stepaniak, 2003

Annual mean net surface flux

OCEAN-ATMOSPHERE TRANSPORTSEstimate of the partitioning of meridional transports by the atmosphere and ocean.

Trenberth and Caron, J. Clim. 2001

At 35° latitude, where the peak polewards transport occurs the atmosphere accounts for 78% (NH) and 92% (SH) of the total. Values estimated from atmospheric analyses agree with direct ocean estimates and those from the best coupled climate models (including CCSM).

Departures from annual mean:Equivalent ocean heat content

(Ignores annual cycle in ocean heat transports)

Data from Climate Monitoring and Diagnostics Lab., NOAA. Data prior to 1973 from C. Keeling, Scripps Inst. Oceanogr.

Changing atmospheric Changing atmospheric composition: COcomposition: CO22

Mauna Loa, HawaiiMauna Loa, Hawaii

The enhanced greenhouse effect

CO2 has increased >30%

If CO2 were suddenly doubled then:• atmosphere must warm up to restore balance via radiation to space• In absence of other changes: warming is 1.2°C• Feedbacks cause complications• Best estimate is warming of 2.5°C so feedbacks roughly double change• Real world changes complex and more gradual

Annual mean departures from the 1961-90 average for global temperatures, mean 14.0°C, and carbon dioxide concentrations from ice cores and Mauna Loa (1958 on), mean 333.7 ppmv.

Karl and Trenberth 2003

The Global Mean Radiative Forcing of the Climate System for the Year 2000, Relative to

1750

What about changes in the ocean heat content?

Changes in Ocean heat content in upper 3000 m

Changes in Ocean heat content in upper 300 m

Contributes to rise in sea level.

Levitus et al. 2000

New global observations by satellite: TOPEX-Poseiden, Jason 1993-2003Thermal expansion can account for almost all in 1990s, but sea level rise from melting glaciers etc is about 1 mm/yr. Increased use (irrigation) and storage (reservoirs) on land –1 mm/yr.

Cazenave and Nerem, 2004

If true: heat going into ocean could be 1.5 W m-2 but other estimates are more like 0.95 W m-2 Willis et al. 2004*0.7 to account for area of ocean.

Oceans and Sea Level

Year ClimateSensitivity

Comments

1990 3 °C “The best understood feedback mechanism iswater vapor feedback, and this is intuitively easyto understand” (IPCC 1990).

1995 2.5-4.5 °C “There is no compelling evidence that water vaporfeedback is anything other thanpositive—although there may be difficulties withupper tropospheric water vapor” (IPCC 1992).

“Feedback from the redistribution of water vaporremains a substantial source of uncertainty inclimate models—Much of the current debate hasbeen addressing feedback from the tropical uppertroposphere” (IPCC 1995).

2001 1.4-5.8 °C “Probably the greatest uncertainty in futureprojections of climate arises from clouds and theirinteractions with radiation” (IPCC 2001).

Prince’s DilemmaIt happens then as it does to physicians in the

treatment of consumption, which in the commencement is easy to cure and difficult to

understand; but when it has neither been discovered in due time nor treated upon a proper principle, it

becomes easy to understand and difficult to cure. The same happens in state affairs; by foreseeing them at a distance … the evils which might arise from them are soon cured; but when, from want of foresight, they are

suffered to increase to such a height that they are perceptible to everyone, there is no longer any

remedy.

[Machiavelli, The Prince, Chapter 3]

The Northern Hemisphere annular mode (NAM)

Sea-level pressure regressed on an index of the NAM

e.g., Thompson and Wallace 2000

The Southern Hemisphere annular mode (SAM)

850-hPa height regressed on an index of the SAM

e.g., Kidson, Karoly, Trenberth, etc.

The Northern Hemisphere Annular Mode (NAM)

HIGH

LOW

HIGH

Storm activity

30% of winter variance

Climate impacts of the NAM

Surface temperature regressed on the NAM index

Provided courtesy of Todd Mitchell, UW

Evolution of Vortex WeakeningONSET

[u] [T] EP Flux

10

30

20

0

Alti

tude

(km

)

10

30

300

100

1000

Pressure (hP

a)

40S EQ 80N40N 40S EQ 80N40N 40S EQ 80N40N

50 hPa 1000 hPa250 hPa

Hei

ght

Fie

ld

c.i. = 3 dam) c.i. = 1 dam) c.i. = 0.5 dam)

Evolution of Vortex WeakeningGROWTH

[u] [T] EP Flux

10

30

20

0

Alti

tude

(km

)

10

30

300

100

1000

Pressure (hP

a)

40S EQ 80N40N 40S EQ 80N40N 40S EQ 80N40N

50 hPa 1000 hPa250 hPa

Hei

ght

Fie

ld

c.i. = 3 dam) c.i. = 1 dam) c.i. = 0.5 dam)

Evolution of Vortex WeakeningMATURE

[u] [T] EP Flux

10

30

20

0

Alti

tude

(km

)

10

30

300

100

1000

Pressure (hP

a)

40S EQ 80N40N 40S EQ 80N40N 40S EQ 80N40N

50 hPa 1000 hPa250 hPa

Hei

ght

Fie

ld

c.i. = 3 dam) c.i. = 1 dam) c.i. = 0.5 dam)

Evolution of Vortex WeakeningDECLINE

[u] [T] EP Flux

10

30

20

0

Alti

tude

(km

)

10

30

300

100

1000

Pressure (hP

a)

40S EQ 80N40N 40S EQ 80N40N 40S EQ 80N40N

50 hPa 1000 hPa250 hPa

Hei

ght

Fie

ld

c.i. = 3 dam) c.i. = 1 dam) c.i. = 0.5 dam)

Evolution of Vortex WeakeningDECAY

[u] [T] EP Flux

10

30

20

0

Alti

tude

(km

)

10

30

300

100

1000

Pressure (hP

a)

40S EQ 80N40N 40S EQ 80N40N 40S EQ 80N40N

50 hPa 1000 hPa250 hPa

Hei

ght

Fie

ld

c.i. = 3 dam) c.i. = 1 dam) c.i. = 0.5 dam)

More Remarks

JET

warmer

JET

VORTEX

warmer

LOW NAM

momentum flux

NORTH POLEEQUATOR

TROPOSPHERE

STRATOSPHERE

TROPOPAUSE

ALT

ITU

DE

(km

)

WINTERTIMEEAST

heat flux

heat flux

QBO

ENSO

Example of inter-calibration

• A-SST off Portugal• B-T Greenland• C-T Antarctic• Deep ocean T, carbonate shells

History of climate during last 43,000 yrs.

• O18 (A, B) and Methane (C)

• Major instabilities until 11,000 ybp

• Stability after Younger Dryas

Ocean circulation• Ocean circulation distributes temperature around globe

• Figure shows modern ocean convection

• There are other “stable”convection patterns

Climate crisis, Younger Dryas

• The last cold period before present; 12,900-11500 YBP

• Cold and dry

• Fast onset & cut-off--(75 years, )

Acknowledgements

• NASA• NSF• JPL• K. Trenberth• D. Thompson• W. Chen• V. Limpasuvan• J. Feynman and A. Ruzmaikin