Paper ReviewPaper Review

B94209025 B94209025 馮培寧 馮培寧 Kirsten FengKirsten Feng

IntroductionIntroduction

<<Tropical Pacific Climate and Its Resons<<Tropical Pacific Climate and Its Resonse to Global Warming in the Kiel Climate Me to Global Warming in the Kiel Climate Model>>odel>>

<<Slowdown of the Meridional Overturning <<Slowdown of the Meridional Overturning Circulation in the Upper Pacific Ocean>>Circulation in the Upper Pacific Ocean>>

<<Pacific Decadal Variability : The Tropica<<Pacific Decadal Variability : The Tropical Pacific Mode and the North Pacific Model Pacific Mode and the North Pacific Mode>>>>

Tropical Pacific Climate and Its RTropical Pacific Climate and Its Resonse to Global Warming in the esonse to Global Warming in the

Kiel Climate ModelKiel Climate Model

Tropical Pacific ClimateTropical Pacific Climate

Kiel Climate ModelKiel Climate ModelEight experiments with different initial condEight experiments with different initial cond

itions.itions.No flux adjustment for correctionNo flux adjustment for correctionCoupled air-sea feedbacks in the tropical Coupled air-sea feedbacks in the tropical

Pacific influence its annual mean state, anPacific influence its annual mean state, annual cycle, and interannual variability. nual cycle, and interannual variability.

Tropical Pacific ClimateTropical Pacific Climate

Tropical Pacific ClimateTropical Pacific Climate

Eastward Zonal Wind StressEastward Zonal Wind Stress

Wind StressWind Stress

PrecipitationPrecipitation

Vertical TemperatureVertical Temperature

2020°°C Isotherm DepthC Isotherm Depth

Hovmoeller DiagramHovmoeller Diagram SST anomaliesSST anomalies

Corresponding SpectraCorresponding Spectra

Standard DeviationsStandard Deviations

TC and STC IndicesTC and STC Indices

Reasonable ApproximationReasonable Approximation

Slowdown of the Meridional OvertSlowdown of the Meridional Overturning Circulation in the Upper Paurning Circulation in the Upper Pa

cific Oceancific Ocean

Meridional Overturning CirculationMeridional Overturning Circulation

Decadal temperature fluctuations in the PaDecadal temperature fluctuations in the Pacific Ocean have a significant effect on macific Ocean have a significant effect on marine ecosystems and the climate of North rine ecosystems and the climate of North America. America.

Some theories ascribe a central role to the Some theories ascribe a central role to the wind-driven meridonal overturning circulatiwind-driven meridonal overturning circulation between the tropical and subtropical ocon between the tropical and subtropical oceans.eans.

Meridional Overturning CirculationMeridional Overturning Circulation

Meridional Overturning CirculationMeridional Overturning Circulation

From the observation over the past 50 From the observation over the past 50 years, that this overturning circulation has years, that this overturning circulation has been slowing down since the 1970s, been slowing down since the 1970s, causing the decrease in upwelling of about causing the decrease in upwelling of about 25% in an equatorial strip between 925% in an equatorial strip between 9°°N N and 9and 9°°S.S.

Meridional Overturning CirculationMeridional Overturning Circulation

The pycnocline normally slopes down to thThe pycnocline normally slopes down to the west near the Equator, under the influene west near the Equator, under the influence of easterly trade wind forcing.ce of easterly trade wind forcing.

The difference between surface-layer tranThe difference between surface-layer transport divergence and pycnocline transport sport divergence and pycnocline transport convergence across 9N and 9S should reflconvergence across 9N and 9S should reflect flow in the western boundary currents.ect flow in the western boundary currents.

Meridional Overturning CirculationMeridional Overturning Circulation

The net transportation decreased in the paThe net transportation decreased in the past 50 yaers (1950 ~ 2000).st 50 yaers (1950 ~ 2000).

Meridional Overturning CirculationMeridional Overturning Circulation

The relationship between the net transport The relationship between the net transport and the temperature anomalies.and the temperature anomalies.

Meridional Overturning CirculationMeridional Overturning Circulation

To compare the difference between 1990-99 To compare the difference between 1990-99 and 1970-79, for 1990-99 minus 1970-79. and 1970-79, for 1990-99 minus 1970-79.

Meridional Overturning CirculationMeridional Overturning Circulation

Decadal difference in the tropical Pacific Decadal difference in the tropical Pacific between 1990-99 and 1970-79.between 1990-99 and 1970-79.

Meridional Overturning CirculationMeridional Overturning Circulation

The wind-driven meridional overturning circulatioThe wind-driven meridional overturning circulation in the upper Pacific Ocean has been slowing dn in the upper Pacific Ocean has been slowing down since the 1970s. own since the 1970s.

Weaker easterly trade winds in the equatorial PaWeaker easterly trade winds in the equatorial Pacific would result in reduced Ekman and geostrocific would result in reduced Ekman and geostrophic meridional transports, reduced equatorial uphic meridional transports, reduced equatorial upwelling, and warmer equatorial upwelling, and pwelling, and warmer equatorial upwelling, and warmer equatorial sea surface temperatures. warmer equatorial sea surface temperatures.

Meridional Overturning CirculationMeridional Overturning Circulation

The further we want to know about this, thThe further we want to know about this, the planetary –scale ocean waves may be a e planetary –scale ocean waves may be a possible way. And it may also be a issue tpossible way. And it may also be a issue that the mechanism between interannual- ahat the mechanism between interannual- and decadal timescale phenomena in the Pnd decadal timescale phenomena in the Pacific.acific.

Pacific Decadal Variability : The TrPacific Decadal Variability : The Tropical Pacific Mode and the North opical Pacific Mode and the North

Pacific ModePacific Mode

Pacific Decadal VariabilityPacific Decadal Variability

EOF = Empirical Orthogonal FunctionEOF = Empirical Orthogonal FunctionREOF = Rotated Empirical Orthogonal REOF = Rotated Empirical Orthogonal

FunctionFunctionFOAM = Fast Ocean-Atmosphere ModelFOAM = Fast Ocean-Atmosphere ModelTPM = Tropical Pacific ModeTPM = Tropical Pacific ModeNPM = Northern Pacific ModeNPM = Northern Pacific ModeSSTA = Sea Surface Temperature SSTA = Sea Surface Temperature

AnomaliesAnomalies

Pacific Decadal VariabilityPacific Decadal Variability

There are two coupled global ocean-atmosThere are two coupled global ocean-atmospheric simulations called partial coupling pheric simulations called partial coupling (PC) and partial blocking (PB).(PC) and partial blocking (PB).

The combination of these two models provThe combination of these two models provides an important modeling surgical techniides an important modeling surgical technique for assessing the role of coupled oceaque for assessing the role of coupled ocean-atmosphere feedbacks and the teleconnn-atmosphere feedbacks and the teleconnection within the ocean in generating climaection within the ocean in generating climate variability.te variability.

Pacific Decadal VariabilityPacific Decadal Variability

Pacific Decadal VariabilityPacific Decadal Variability