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The pathway of the interdecadal variability in the Pacific Ocean
Dongxiao Wang,Zhengyu Liu
Chinese Science Bulletin , 2000, DOI: 10.1007/BF02886211
Abstract: Cases of the interdecadal variability in the Pacific Ocean and their evolution were examined in the paper with the statistic methods (CEOF and composite analysis) over the period of 1950–1993. Observations of oceanic temperatures in the upper 400 m revealed an obvious region of the interdecadal signals in the central North Pacific. Such signals propagated southwestward, then subducted to the subtropics. The hypothesized link for interdecadal oceanic variability between the subtropics and the tropics, especially with the western tropical Pacific was unraveled in order to detect the cause of decadal signals in the tropics. The thermal anomalies subducted in the central North Pacific east to the dateline only reach 18°N. There has been no further southward propagation since then due to a certain barrier. The origin of the interdecadal signals in the western tropical Pacific was traced to the southern tropical Pacific. There is a meridional pathway around the dateline where the signals were loaded. These variabilities were in the nature of the thermocline circulation.
Numerical Simulation of Impacts of Sea Surface Temperature Anomaly upon the Interdecadal Variation in the Northwestern Pacific Subtropical High

ZENG Gang,SUN Zhaobo,LIN Zhaohui,NI Donghong,

大气科学 , 2010,
Abstract: Impacts of regional sea surface temperature anomaly(SSTA)on the interdecadal variation of the Northwestern Pacific Subtropical High(NWPSH)are studied by numerical simulation with the NCAR CAM3 global atmospheric circulation model drived by 1950-2000 monthly SST in different sea areas(global,extratropical,tropical,tropical Indian Ocean-Pacific,tropical Indian Ocean,and tropical Pacific),in comparison with observational data.Results suggest that the change in the global,tropical,tropical Indian Ocean-Pacific,...
On the Decadal and Interdecadal Variability in the Pacific Ocean

YANG Haijun,ZHANG Qiong,
YANG Haijun
,ZHANG Qiong

大气科学进展 , 2003,
Abstract: The Pacific decadal and interdecadal oscillation (PDO) has been extensively explored in recent decades because of its profound impact on global climate systems. It is a long-lived ENSO-like pattern of Pacific climate variability with a period of 10-30 years. The general picture is that the anomalously warm (cool) SSTs in the central North Pacific are always accompanied by the anomalously cool (warm) SSTs along the west coast of America and in the central east tropical Pacific with comparable amplitude. In general, there are two classes of opinions on the origin of this low-frequency climate variability, one thinking that it results from deterministically coupled modes of the Pacific ocean-atmosphere system, and the other, from stochastic atmospheric forcing. The deterministic origin emphasizes that the internal physical processes in an air-sea system can provide a positive feedback mechanism to amplify an initial perturbation, and a negative feedback mechanism to reverse the phase of oscillation. The dynamic evolution of ocean circulation determines the timescale of the oscillation. The stochastic origin, however, emphasizes that because the atmospheric activities can be thought as having no preferred timescale and are associated with an essentially white noise spectrum, the ocean response can manifest a red peak in a certain low frequency range with a decadal to interdecadal timescale. In this paper, the authors try to systematically understand the state of the art of observational, theoretical and numerical studies on the PDO and hope to provide a useful background reference for current research.
Relationship between Interdecadal Variation of North Pacific-Equatorial Indian Ocean SST and Transition of Rainfall Pattern in East China around the 1970s

GU Wei,LI Chong-Yin,PAN Jing,

气候与环境研究 , 2007,
Abstract: Orthogonal wavelet analysis of summer rainfall in East China showed its opposite spatial pattern before and after the 1970s,mainly the opposite situation of precipitation in North China and in the middle and lower reaches of the Yangtze River.The difference of meridional position of the summer East Asian upper-tropospheric Jet Stream(EAJS) and West Pacific Subtropical High(WPSH) before and after the 1970s was one of the most important reasons for the transition of summer rainfall pattern.Besides,on interdecadal time scales,North Pacific and Tropical Indian Ocean Sea Surface Temperature Anomaly(SSTA) variated coherently,and were closely related to the transition of summer rainfall pattern in East China.What's more,North Pacific-Equatorial Indian Ocean Sea Surface Temperatures(SST)showed a certain relationship with the north-south movement of EAJS and WPSH on both interannual and interdecadal time scales.Thus,North Pacific-Equatorial Indian Ocean SST was indeed an important factor for the prediction of summer rainfall pattern in East China.
Interdecadal Enhancement of the Walker Circulation over the Tropical Pacific in the Late 1990s

Buwen DONG,LU Riyu,

大气科学进展 , 2013,
Abstract: The Walker circulation is one of the major components of the large-scale tropical atmospheric circulation and variations in its strength are critical to equatorial Pacific Ocean circulation. It has been argued in the literature that during the 20th century the Walker circulation weakened, and that this weakening was attributable to anthropogenic climate change. By using updated observations, we show that there has been a rapid interdecadal enhancement of the Walker circulation since the late 1990s. Associated with this enhancement is enhanced precipitation in the tropical western Pacific, anomalous westerlies in the upper troposphere, descent in the central and eastern tropical Pacific, and anomalous surface easterlies in the western and central tropical Pacific. The characteristics of associated oceanic changes are a strengthened thermocline slope and an enhanced zonal SST gradient across the tropical Pacific. Many characteristics of these changes are similar to those associated with the mid-1970s climate shift with an opposite sign. We also show that the interdecadal variability of the Walker circulation in the tropical Pacific is inversely correlated to the interdecadal variability of the zonal circulation in the tropical Atlantic. An enhancement of the Walker circulation in the tropical Pacific is associated with a weakening zonal circulation in the tropical Atlantic and vise versa, implying an inter-Atlantic-Pacific connection of the zonal overturning circulation variation. Whether these recent changes will be sustained is not yet clear, but our research highlights the importance of understanding the interdecadal variability, as well as the long-term trends, that influence tropical circulation.
The Effect of Heat Flux and Wind Stress on the Interannual and Interdecadal Variability of SST in the North Pacific Simulated by an OGCM

WU Chunqiang,ZHOU Tianjun,YU Rucong and,

大气科学 , 2009,
Abstract: The roles of wind stress and surface heat flux in generating the Pacific interannual and interdecadal variability are examined by using two sets of simulations performed with LASG/IAP climate ocean model named LICOM. It is found that the interannual variability of SST in the tropical Pacific is mainly controlled by wind stress,however,the simulation of El Nio is improved significantly when surface heat flux is considered. The interannual variability of SST in the North Pacific is generated by the effect of ...
Model Evidence for Interdecadal Pathway Changes in the Subtropics and Tropics of the South Pacific Ocean

ZHANG Rong-Hua,WANG Zhanggui,

大气科学进展 , 2013,
Abstract: Numerical simulations using a version of the GFDL/NOAA Modular Ocean Model (MOM 3) are analyzed to demonstrate interdecadal pathway changes from the subtropics to the tropics in the South Pacific Ocean. After the 1976–77 climate shift, the subtropical gyre of the South Pacific underwent significant changes, characterized by a slowing down in its circulation and a southward displacement of its center by about 5°–10° latitude on the western side. The associated circulation altered its flow path in the northwestern part of the subtropical gyre, changing from a direct pathway connecting the subtropics to the tropics before the shift to a more zonal one after. This effectively prevented some subtropical waters from directly entering into the western equatorial Pacific. Since waters transported onto the equator around the subtropical gyre are saline and warm, such changes in the direct pathway and the associated reduction in equatorward exchange from the subtropics to the tropics affected water mass properties downstream in the western equatorial Pacific, causing persisted freshening and cooling of subsurface water as observed after the late 1970s. Previously, changes in gyre strength and advection of temperature anomalies have been invoked as mechanisms for linking the subtropics and tropics on interdecadal time scales. Here we present an additional hypothesis in which geographic shifts in the gyre structure and location (a pathway change) could play a similar role.
Dynamic Linkage between the North Pacific and the Tropical Pacific: Atmosphere--Ocean Coupling

LI Chun,WU Lixin,

大气科学进展 , 2013,
Abstract: In this study, dynamic linkage of atmosphere-ocean coupling between the North Pacific and the tropical Pacific was demonstrated using a large number of ensemble perturbed initial condition experiments in a fully coupled fast ocean-atmosphere model (FOAM). In the FOAM model, an idealized mixed layer warming was initiated in the Kuroshio-Oyashio extension region, while the ocean and atmosphere remained fully coupled both locally and elsewhere. The modeling results show that the warm anomalies are associated with anomalous cyclonic winds, which induce initial warming anomalies extending downstream in the following winter. Then, the downstream warming spreads southwestward and induces SST warming in the equatorial Pacific via surface wind-evaporation-SST feedback. Warming in the tropical Pacific is further reinforced by Bjerknes’ feedback.
The Oscillation between Tropical Indian Ocean and North Pacific:Evidence and Possible Impact on Winter Climate in China
The Oscillation between Tropical Indian Ocean and North Pacific: Evidence and Possible Impact on Winter Climate in China

HU Kai-Ming,HUANG Gang,
HU Kai-Ming

大气和海洋科学快报 , 2011,
Abstract: This paper provides evidence that the variation of boreal winter sea level pressure (SLP) over the North Pacific is out-of-phase with SLP fluctuation over the tropical Indian Ocean on both the interdecadal and interannual time scales. Subsequently, a SLP between tropical Indian Ocean and North Pacific (TIO-NP) oscillation index is defined to indicate the variation of such out-of-phase fluctuation. Moreover, the simultaneous surface air temperature and precipitation anomalies in China are closely related to TIO-NP oscillations. Below-normal surface air temperature anomalies in the northern and the eastern part of China, and less rainfall in southern China, correspond to positive TIO-NP oscillation phase with negative SLP anomalies in tropical Indian Ocean and positive anomalies in North Pacific. The TIO-NP oscillation affects China’s winter climate anomalies, possibly through modulating the northeast East Asia winter monsoon.
Interdecadal change in Western Pacific Subtropical High and climatic effects
西太平洋副热带高压的年代际变化 及其气候影响

HE Xue-zhao,GONG Dao-yi,

地理学报 , 2002,
Abstract: Western North Pacific Subtropical High is a very important atmospheric circulation system influencing the summer climate over eastern China. Its interdecadal change is analyzed in this study. There is a significant decadal shift in about 1979/1980. Since 1980, the Western North Pacific Subtropical High has enlarged, intensified, and shifted southwestward. This change gives rise to an anti-cyclonic circulation anomaly over the region from the South China Sea to Western Pacific and thus causes wet anomalies over the Yangtze River valley. During the summers of 1980-1999, the precipitation is 63.9 mm above normal, while during 1958-1979 it is 27.3 mm below normal. The difference is significant at the 99% confidence level as a t - test shown. The southwestward expanding of the Western North Pacific Subtropical High also leads to a significant warming in the southern China, during the 1980-1999 the summer mean temperature is 0.37oC warmer than that of the period 1958-1979. The strong warming is primarily due to the clearer skies associated with the stronger downward air motion as the Western North Pacific Subtropical High expanding to the west. It is also found that the relative percentage of tropical cyclones in the regions south of 20oN has been decreasing since the 1980s, but that in the regions north of 20oN has been increasing during the same period. The Western North Pacific Subtropical High responds significantly to sea surface temperature of the tropical eastern Pacific with a lag of one-two seasons and simultaneously to sea surface temperature of the tropical Indian Ocean. The changes in the sea surface temperatures are mainly responsible for the interdecadal variability of the Western North Pacific Subtropical High.
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