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Paper Review. B94209025 馮培寧 Kirsten Feng. Introduction. <<Tropical Pacific Climate and Its Resonse to Global Warming in the Kiel Climate Model>> <<Slowdown of the Meridional Overturning Circulation in the Upper Pacific Ocean>>
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Paper Review B94209025 馮培寧 Kirsten Feng
Introduction • <<Tropical Pacific Climate and Its Resonse to Global Warming in the Kiel Climate Model>> • <<Slowdown of the Meridional Overturning Circulation in the Upper Pacific Ocean>> • <<Pacific Decadal Variability : The Tropical Pacific Mode and the North Pacific Mode>>
Tropical Pacific Climate and Its Resonse to Global Warming in the Kiel Climate Model
Tropical Pacific Climate • Kiel Climate Model • Eight experiments with different initial conditions. • No flux adjustment for correction • Coupled air-sea feedbacks in the tropical Pacific influence its annual mean state, annual cycle, and interannual variability.
Hovmoeller Diagram • SST anomalies
Slowdown of the Meridional Overturning Circulation in the Upper Pacific Ocean
Meridional Overturning Circulation • Decadal temperature fluctuations in the Pacific Ocean have a significant effect on marine ecosystems and the climate of North America. • Some theories ascribe a central role to the wind-driven meridonal overturning circulation between the tropical and subtropical oceans.
Meridional Overturning Circulation • From the observation over the past 50 years, that this overturning circulation has been slowing down since the 1970s, causing the decrease in upwelling of about 25% in an equatorial strip between 9°N and 9°S.
Meridional Overturning Circulation • The pycnocline normally slopes down to the west near the Equator, under the influence of easterly trade wind forcing. • The difference between surface-layer transport divergence and pycnocline transport convergence across 9N and 9S should reflect flow in the western boundary currents.
Meridional Overturning Circulation • The net transportation decreased in the past 50 yaers (1950 ~ 2000).
Meridional Overturning Circulation • The relationship between the net transport and the temperature anomalies.
Meridional Overturning Circulation • To compare the difference between 1990-99 and 1970-79, for 1990-99 minus 1970-79.
Meridional Overturning Circulation • Decadal difference in the tropical Pacific between 1990-99 and 1970-79.
Meridional Overturning Circulation • The wind-driven meridional overturning circulation in the upper Pacific Ocean has been slowing down since the 1970s. • Weaker easterly trade winds in the equatorial Pacific would result in reduced Ekman and geostrophic meridional transports, reduced equatorial upwelling, and warmer equatorial upwelling, and warmer equatorial sea surface temperatures.
Meridional Overturning Circulation • The further we want to know about this, the planetary –scale ocean waves may be a possible way. And it may also be a issue that the mechanism between interannual- and decadal timescale phenomena in the Pacific.
Pacific Decadal Variability : The Tropical Pacific Mode and the North Pacific Mode
Pacific Decadal Variability • EOF = Empirical Orthogonal Function • REOF = Rotated Empirical Orthogonal Function • FOAM = Fast Ocean-Atmosphere Model • TPM = Tropical Pacific Mode • NPM = Northern Pacific Mode • SSTA = Sea Surface Temperature Anomalies
Pacific Decadal Variability • There are two coupled global ocean-atmospheric simulations called partial coupling (PC) and partial blocking (PB). • The combination of these two models provides an important modeling surgical technique for assessing the role of coupled ocean-atmosphere feedbacks and the teleconnection within the ocean in generating climate variability.