江西省冬季气温异常与区域海温的关联

利用1960-2010年江西省81个台站月平均气温观测资料和NOAA全球月平均海表温度资料(ERSST-V3),分析了江西省冬季气温异常与海温异常的相互联系,并运用超前-滞后相关分析和奇异值分解(SVD)方法初步探讨了关键区海温异常之间的相互作用.结果表明:①影响江西省冬季气温异常的海温关键区和关键时段分别为同期印度洋(10°S～20°N,54°～90°E)、同期西北太平洋(20°～40°N,120°～180°E)和前期8-9月北大西洋中部(24°～44°N,20°～60°W)海域;②西北太平洋关键区暖水年预示暖冬年好于印度洋区,而印度洋区冷水年预示冷冬年稍好于西北太平洋区,冬季西北太平洋与印度洋海温异常可以修正前期8-9月北大西洋中部海温异常对江西省冬季气温的影响.     

The relative importance of tropical variability forced from the North Pacific through ocean pathways

To what extent is tropical variability forced from the North Pacific through ocean pathways relative to locally generated variability and variability forced through the atmosphere? To address this question, in this study we use an anomaly-coupled model, consisting of a global, atmospheric general circulation model and a 4½-layer, reduced-gravity, Pacific-Ocean model. Three solutions are obtained; with coupling over the entire basin (CNT), with coupling confined to the tropics and wind stress and heat fluxes in the North and South Pacific specified by climatology (TP), and with coupling confined to the Tropics and wind stress and heat fluxes in the North Pacific specified by output from CNT (NPF). It is found that there are two distinct signals forced in the North Pacific that can impact the tropics through ocean pathways. These two signals are forced by wind stress and surface heat flux anomalies in the subtropical North Pacific. The first signal is relatively fast, impacts tropical variability less than a year after forcing, is triggered from November to March, and propagates as a first-mode baroclinic Rossby wave. The second signal is only triggered during springtime when buoyancy forcing can effectively generate higher-order baroclinic modes through subduction anomalies into the permanent thermocline, and it reaches the equator 4–5 years after forcing. The slow signal is found to initiate tropical variability more efficiently than the fast signal with one standard deviation in subtropical zonal wind stress forcing tropical SST anomalies centered on the equator at 135°W of approximately 0.5°C. Allowing extratropically forced tropical variability is found to shift primarily 2-year ENSO variability in a tropics-alone simulation to a more realistic range of 2–6 years.     

Influence of the Boreal Summer Intraseasonal Oscillation on Extreme Temperature Events in the Northern Hemisphere

The impact of the boreal summer intraseasonal oscillation (BSISO) on extreme hot and cool events was investigated, by analyzing the observed and reanalysis data for the period from 1983 to 2012. It is found that the frequency of the extreme events in middle and high latitudes is significantly modulated by the BSISO convection in the tropics, with a 3–9-day lag. During phases 1 and 2 when the BSISO positive rainfall anomaly is primarily located over a northwest–southeast oriented belt extending from India to Maritime Continent and a negative rainfall anomaly appears in western North Pacific, the frequency of extreme hot events is 40% more than the frequency of non-extreme hot events. Most noticeable increase appears in midlatitude North Pacific (north of 40°N) and higher-latitude polar region.Two physical mechanisms are primarily responsible for the change of the extreme frequency. First, an upper-tropospheric Rossby wave train (due to the wave energy propagation) is generated in response to a negative heating anomaly over tropical western North Pacific in phases 1 and 2. This wave train consists of a strong high pressure anomaly center northeast of Japan, a weak low pressure anomaly center over Alaska, and a strong high pressure anomaly center over the western coast of United States. Easterly anomalies to the south of the two strong midlatitude high pressure centers weaken the climatological subtropical jet along 40°N, which is accompanied by anomalous subsidence and warming in North Pacific north of 40°N. Second, an enhanced monsoonal heating over South Asia and East Asia sets up a transverse monsoonal overturning circulation, with large-scale ascending (descending) anomalies over tropical Indian (Pacific) Ocean. Both the processes favor more frequent extreme hot events in higher-latitude Northern Hemisphere. An anomalous atmospheric general circulation model is used to confirm the tropical heating effect.     

High-resolution numerical simulation of the Pacific Ocean

The present study developed Pacific Ocean models from the Research Institute for Applied Mechanics Ocean Model (RIAMOM) with very high horizontal (1/6° and 1/12°) and vertical (70 levels) resolutions. The hydrographic features of the simulations show good agreement with observed climatological features. Solution differences between the 1/6° and 1/12° models are small for general features of various physical components, but large for eddy fields and the strengths of western boundary currents and their extensions. However, the two high-resolution models show realistic climatological features of Pacific Ocean circulation patterns. Volume transports through major straits in the northwestern Pacific Ocean were also simulated and compared with previous observational results.     

RESEARCH ON THE INTERANNUAL AND INTERDECADAL VARIABILITIES OF THE MONSOON TROUGH AND THEIR IMPACTS ON TROPICAL CYCLONE GENESIS OVER THE WESTERN NORTH PACIFIC OCEAN

In this paper, we mainly summarize and review the progresses in recent climatological studies (by CMSR, IAP/CAS and some associated domestic and international institutions) on the interannual and interdecadal variabilities of monsoon troughs and their impacts on tropical cyclones and typhoons (TCs) geneses over the western North Pacific Ocean. The climatological characteristics of monsoon troughs and four types of circulation patterns favorable to TCs genesis over the western North Pacific Ocean in summer and autumn are given in this paper. It is also shown in this paper that the monsoon trough over the western North Pacific Ocean has obvious interannual and interdecadal variabilities. Especially, it is revealed in this paper that the interannual and interdecadal variabilities of the monsoon trough over the western North Pacific Ocean influence the TCs genesis not only through the impact on distributions of the vorticity in the lower troposphere and the divergence in the upper troposphere, the water vapor in the mid- and lower troposphere and the vertical shear of wind fields between the upper and lower troposphere over the western North Pacific Ocean, but also through the dynamical effects of the transition between convectively coupled tropical waves and providing disturbance energy. Besides, some climatological problems associated with TCs activity over the western North Pacific Ocean that need to be studied further are also pointed out in this paper.     

Modulation of the Pacific Decadal Oscillation on the summer precipitation over East China: a comparison of observations to 600-years control run of Bergen Climate Model

Observations show that the summer precipitation over East China often goes through decadal variations of opposite sign over North China and the Yangtze River valley (YRV), such as the “southern flood and northern drought” pattern that occurred during the late 1970s–1990s. In this study it is shown that a modulation of the Pacific Decadal Oscillation (PDO) on the summer precipitation pattern over East China during the last century is partly responsible for this characteristic precipitation pattern. During positive PDO phases, the warm winter sea surface temperatures (SSTs) in the eastern subtropical Pacific along the western coast of North American propagate to the tropics in the following summer due to weakened oceanic meridional circulation and the existence of a coupled wind–evaporation–SST feedback mechanism, resulting in a warming in the eastern tropical Pacific Ocean (5°N–20°N, 160°W–120°W) in summer. This in turn causes a zonal anomalous circulation over the subtropical–tropical Pacific Ocean that induces a strengthened western Pacific subtropical high (WPSH) and thus more moisture over the YRV region. The end result of these events is that the summer precipitation is increased over the YRV region while it is decreased over North China. The suggested mechanism is found both in the observations and in a 600-years fully coupled pre-industrial multi-century control simulations with Bergen Climate Model. The intensification of the WPSH due to the warming in the eastern tropical Pacific Ocean was also examined in idealized SSTA-forced AGCM experiments.     

Reinterpreting the thermocline feedback in the western-central equatorial Pacific and its relationship with the ENSO modulation

Vertical stratification changes at low frequency over the last decades are the largest in the western-central Pacific and have the potential to modify the balance between ENSO feedback processes. Here we show evidence of an increase in thermocline feedback in the western-central equatorial Pacific over the last 50 years, and in particular after the climate shift of 1976. It is demonstrated that the thermocline feedback becomes more effective due to the increased stratification in the vicinity of the mean thermocline. This leads to an increase in vertical advection variability twice as large as the increase resulting from the stronger ENSO amplitude (positive asymmetry) in the eastern Pacific that connects to the thermocline in the western-central Pacific through the basin-scale ‘tilt’ mode. Although the zonal advective feedback is dominant over the western-central equatorial Pacific, the more effective thermocline feedback allows for counteracting its warming (cooling) effect during warm (cold) events, leading to the reduced covariability between SST and thermocline depth anomalies in the NINO4 (160°E–150°W; 5°S–5°N) region after the 1976 climate shift. This counter-intuitive relationship between thermocline feedback strength as derived from the linear relationship between SST and thermocline fluctuations and stratification changes is also investigated in a long-term general circulation coupled model simulation. It is suggested that an increase in ENSO amplitude may lead to the decoupling between eastern and central equatorial Pacific sea surface temperature anomalies through its effect on stratification and thermocline feedback in the central-western Pacific.     

Boreal winter rainfall anomaly over the tropical indo-pacific and its effect on northern hemisphere atmospheric circulation in CMIP5 models

Experimental outputs of 11 Atmospheric Model Intercomparison Project （AMIP） models from phase 5 of the Coupled Model Intercomparison Project （CMIP5） are analyzed to assess the atmospheric circulation anomaly over Northern Hemisphere induced by the anomalous rainfall over tropical Pacific and Indian Ocean during boreal winter.The analysis shows that the main features of the interannual variation of tropical rainfall anomalies,especially over the Central Pacific （CP） （5°S-5°N,175°E-135°W） and Indo-western Pacific （IWP） （20°S-20°N,110°-150°E） are well captured in all the CMIP5/AMIP models.For the IWP and western Indian Ocean （WIO） （10°S-10°N,45°-75°E）,the anomalous rainfall is weaker in the 11 CMIP5/AMIP models than in the observation.During El Ni（n）o/La Ni（n）a mature phases in boreal winter,consistent with observations,there are geopotential height anomalies known as the Pacific North American （PNA） pattern and Indo-western Pacific and East Asia （IWPEA） pattern in the upper troposphere,and the northwestern Pacific anticyclone （cyclone） （NWPA） in the lower troposphere in the models.Comparison between the models and observations shows that the ability to simulate the PNA and NWPA pattern depends on the ability to simulate the anomalous rainfall over the CP,while the ability to simulate the IWPEA pattern is related to the ability to simulate the rainfall anomaly in the IWP and WIO,as the SST anomaly is same in AMIP experiments.It is found that the tropical rainfall anomaly is important in modeling the impact of the tropical Indo-Pacific Ocean on the extratropical atmospheric circulation anomaly.     

Atmospheric modulation of surface heat fluxes at Ocean Weather Station P on a decadal time‐scale

Abstract

A 30‐year record (1951–1980) of surface heat fluxes at Ocean Weather Station P in the northeastern Pacific Ocean (50°N, 145°W) was examined for differences in the interdecadal variation between fail and winter. During the latter part of the 1950s and the early 1960s, the winter surface heat flux from the ocean to the atmosphere diminished significantly whereas the fall heat flux increased slightly This difference in the modulation of the winter heat flux from the fall heat flux during this period appears to be caused by the presence of an atmospheric circulation anomaly resembling that of the Pacific/North America (PNA) low‐frequency variability mode during the winter season.     

The ENSO Events in the Tropical Pacific and Dipole Events in the Indian Ocean

A depth map (close to that of the thermocline as defined by 20℃) of climatically maximum seatemperature anomaly was created at the subsurface of the tropical Pacific and Indian Ocean, based on which the evolving sea-temperature anomaly at this depth map from 1960 to 2000 was statistically analyzed. It is noted that the evolving sea temperature anomaly at this depth map can be better analyzed than the evolving sea surface one. For example, during the ENSO event in the tropical Pacific, the seatemperature anomaly signals travel counter-clockwise within the range of 10°S-10°N, and while moving, the signals change in intensity or even type. If Dipole is used in the tropical Indian Ocean for analyzing the depth map of maximum sea-temperature anomaly, the sea-temperature anomalies of the eastern and western Indian Oceans would be negatively correlated in statistical sense (Dipole in real physical sense), which is unlike the sea surface temperature anomaly based analysis which demonstrates that the inter-annual positive and negative changes only occur on the gradients of the western and eastern temperature anomalies. Further analysis shows that the development of ENSO and Dipole has a time lag features statistically, with the sea-temperature anomaly in the eastern equatorial Pacific changing earlier (by three months or so). And the linkage between these two changes is a pair of coupled evolving Walker circulations that move reversely in the equatorial Pacific and Indian Oceans.     

春夏季节转换中西太平洋副热带高压东移与大尺度环流和温度场变化关系

分析了由春向夏的季节转换过程中西太平洋副热带高压与大尺度环流和温度场之间的变化关系.结果表明:4月份,西太平洋副热带高压开始表现出向东移动特征,6月份它与向西移动的北美副高在东太平洋120～160 (W区域合并.这一期间,沿15～20 (N之间的纬圈环流同时表现出向东移动特征,该纬圈环流的上升支位于南海-西太平洋暖池一带,下沉支主要位于东太平洋180 (～120 (W区域.伴随上述变化,位于北半球太平洋的局地Hadley环流在纬向随时间表现出东强西弱变化特点.西太平洋副高向东移动与15～20 (N之间的纬圈环流和130 (W东太平洋局地Hadley环流在15～25 (N上空交汇、下沉密切相关.在由春向夏季节转换中,大气和海表温度关于赤道季节转换速率沿纬向表现出东慢西快差异,上述变化为西太平洋副热带高压的向东移动提供了有利的气候背景.     

Mechanisms of tropical Pacific interannual-to-decadal variability in the ARPEGE/ORCA global coupled model

Spatial and temporal structures of interannual-to-decadal variability in the tropical Pacific Ocean are investigated using results from a global atmosphere–ocean coupled general circulation model. The model produces quite realistic mean state characteristics, despite a sea surface temperature cold bias and a thermocline that is shallower than observations in the western Pacific. The periodicity and spatial patterns of the modelled El Niño Southern Oscillations (ENSO) compare well with those observed over the last 100 years, although the quasi-biennial timescale is dominant. Lag-regression analysis between the mean zonal wind stress and the 20°C isotherm depth suggests that the recently proposed recharge-oscillator paradigm is operating in the model. Decadal thermocline variability is characterized by enhanced variance over the western tropical South Pacific (~7°S). The associated subsurface temperature variability is primarily due to adiabatic displacements of the thermocline as a whole, arising from Ekman pumping anomalies located in the central Pacific, south of the equator. Related wind anomalies appear to be caused by SST anomalies in the eastern equatorial Pacific. This quasi-decadal variability has a timescale between 8 years and 20 years. The relationship between this decadal tropical mode and the low-frequency modulation of ENSO variance is also discussed. Results question the commonly accepted hypothesis that the low-frequency modulation of ENSO is due to decadal changes of the mean state characteristics.     

Observation research of the turbulent fluxes of momentum,sensible heat and latent heat over the West Pacific Tropical Ocean Area

This paper describes results of the fluxes of momentum , sensible heat and latent heat for the West Pacific Tropical Ocean Area ( 127 ° E - 150 ° E , 5 ° N -3 ° S ). The data were collected by the small tethered balloon sounding system over this ocean area including 6 continuous stations (140 ° E. 0 ° ; 145 ° E, 0 ° ; 150 ° E, 0 ° ; 140° E, 5 ° N; 145 ° E, 5° N and 150 ° E, 5 ° N) from 11 October to 15 December, 1986 . These fluxes were calculated by the semiempirical flux-profile relationships of Monin-Obukhov similarity theory using these observed data. The results show that for this tropical ocean area the drag coefficient CD is equal to (1.53 ± 0.25) × 10 3 and the daily mean latent flux Hl is greater than its daily mean sensible flux HV by a factor of about 9.     

印度洋—西太平洋对流涛动的季节内特征

本文利用30~60天带通滤波资料, 考察了不同季节印度洋—西太平洋区域对流活动季节内尺度变率的主要模态, 发现在不同季节赤道东印度洋(5°S~10°N, 70°E~100°E)和西北太平洋(5°N~20°N, 110°E~160°E)对流活动均存在反相变化的关系, 将之称为季节内尺度的印度洋—西太平洋对流涛动(Indo-West Pacific Convection Oscillation), 简称IPCO。对IPCO两极子区域对流活动进行超前滞后相关分析, 发现IPCO事件形成—发展—消亡的生命周期是由对流活动季节内振荡及其传播造成的。对流扰动首先在赤道中西印度洋形成, 随后逐渐向东发展变强, 在其继续变强的过程中将分两支传播:一支由赤道印度洋向北传播, 至印度半岛南部后逐渐减弱消失;另一支沿赤道继续东传, 在海洋大陆受到抑制, 快速越过海洋大陆到达赤道西太平洋后又开始发展变强, 随后北传至西北太平洋区域逐渐减弱, 最终至我国长江流域中下游到日本区域消失。将这一过程划分为8个位相, 详细分析了不同位相对应的环流场和降水场特征, 最后给出了IPCO事件演化示意图。     

一个压力坐标海洋环流模式(PCOM1.0)的基本模拟性能评估

参照Griffies et al.(2009)提出的海洋—海冰耦合模式参考试验(Coordinated Ocean-ice Reference Experiments,COREs),设计了一个800年积分的数值试验,对一个质量严格守恒的压力坐标海洋环流模式(Pressure Coordinate Ocean Model,PCOM1.0)的基本模拟性能进行了评估,并与观测资料和再分析资料进行了对比。结果表明,PCOM1.0模拟的温盐场和基本流场与COREs模式的模拟水平基本接近。其中,模拟的大西洋经向翻转流在45°N附近达到18 Sv(1 Sv=106 m3 s-1),与观测估计值接近;对海表面温度的模拟误差主要集中在北太平洋黑潮区和北大西洋湾流区等中高纬度急流区;模拟的热带太平洋温跃层过于深厚;模拟的经德雷克海峡的体积输送达130 Sv,比大部分COREs模式及再分析资料都更接近于观测估计值。     

印度洋海温异常对西北太平洋台风的影响及机制研究

基于近40 a NCEP/NCAR再分析月平均高度场、风场、涡度场、垂直速度场以及NOAA重构的海面温度（sea surface temperature,SST）资料和美国联合台风预警中心（Joint Typhoon Warning Center, JTWC）热带气旋最佳路径资料,利用合成分析方法,研究了前期春季及同期夏季印度洋海面温度同夏季西北太平洋台风活动的关系。结果表明：1）前期春季印度洋海温异常（sea surface temperature anoma1y,SSTA）尤其是关键区位于赤道偏北印度洋和西南印度洋地区对西北太平洋台风活动具有显著的影响,春季印度洋海温异常偏暖年,后期夏季,110°～180°E的经向垂直环流表现为异常下沉气流,对应风场的低层低频风辐散、高层辐合的形势,这种环流形势使得低层水汽无法向上输送,对流层中层水汽异常偏少,纬向风垂直切变偏大,从而夏季西北太平洋台风频数偏少、强度偏弱,而异常偏冷年份则正好相反。2）春季印度洋异常暖年,西北太平洋副热带高压加强、西伸;而春季印度洋异常冷年,后期夏季西北太平洋副热带高压减弱、东退,这可能是引起夏季西北太平洋台风变化的另一原因。     

An upper‐ocean general circulation model for the north pacific: Preliminary experiments

Abstract

A model with two active layers, a mixed layer and a pycnocline layer, over a semipassive deep ocean is described. The model is used to simulate a climatological seasonal cycle in the upper North Pacific. The formulation is similar to that in Cherniawsky et al. (1990). The model resolution is 1° latitude by 1.5° longitude, extending from 62°N to the equator. It is driven with monthly wind stress (Hellerman and Rosenstein, 1983) and with Newtonian heat and freshwater fluxes, which were inferred from climatological (Levitus, 1982) sea‐surface monthly temperatures and annual mean salinities. The monthly temperature anomalies (without the annual mean) are multiplied by a prescribed gain factor and advanced in time, compensating for time delay in the response of the mixed layer. No‐slip and no‐flux constraints are applied on north, east, west and land boundaries, while the following open boundary conditions are used at the equator: (a) free‐slip on zonal velocities in the two layers; (b) a prescribed meridional transport, due to local curl of the wind stress, in the mixed layer; (c) an antisymmetric meridional velocity plus a small flux‐balancing term in the second layer; and (d) across‐equator symmetry for layer depths, temperatures and salinities. Sensitivity to two aspects of parametrization is investigated: (1) the change to horizontal diffusion/viscosity coefficients that depend on the velocity deformation field (as in Smagorinsky, 1963), and (2) the use of idealized piecewise‐linear profiles for second‐layer temperatures and salinities for calculating mixed layer entrainment fluxes.     

Spring Arctic Oscillation-East Asian summer monsoon connection through circulation changes over the western North Pacific

In the present study the links between spring Arctic Oscillation (AO) and East Asian summer monsoon (EASM) was investigated with focus on the importance of the North Pacific atmospheric circulation and sea surface temperature (SST). To reduce the statistical uncertainty, we analyzed high-pass filtered data with the inter-annual time scales, and excluded the El Ni?o/Southern Oscillation signals in the climate fields using a linear fitting method. The significant relationship between spring AO and EASM are supported by the changes of multi-monsoon components, including monsoon indices, precipitation, and three-dimensional atmospheric circulations. Following a stronger positive spring AO, an anomalous cyclonic circulation at 850?hPa appears in southeastern Asia and the western North Pacific in summer, with the easterly anomalies spanning from the Pacific to Asian continent along 25°N?C30°N and the westerly anomalies south of 15°N. At the same time, the summer western North Pacific subtropical high becomes weaker. Consistently, the positive precipitation anomalies are developed over a broad region south of 30°N stretching from southern China to the western Pacific and the negative precipitation anomalies appear in the lower valley of the Yangtze River and southern Japan. The anomalous cyclone in the western North Pacific persisting from spring to summer plays a key role in modulating EASM and monsoon precipitation by a positive air-sea feedback mechanism. During spring the AO-associated atmospheric circulation change produces warmer SSTs between 150°E?C180° near the equator. The anomalous sensible and latent heating, in turn, intensifies the cyclone through a Gill-type response of the atmosphere. Through this positive feedback, the tropical atmosphere and SST patterns sustain their strength from spring to summer, that consequently modifies the monsoon trough and the western North Pacific subtropical high and eventually the EASM precipitation. Moreover, the SST response to AO-circulation is supported by the numerical simulations of an ocean model, and the anomalous atmospheric circulation over the western North Pacific is also reproduced by the dedicated numerical simulations using the coupled atmosphere?Cocean model. The observation evidence and numerical simulations suggest the spring AO can impact the EASM via triggering tropical air-sea feedback over the western North Pacific.     

Interannual variability of the upper layer of the tropical Atlantic Ocean from in situ data between 1979 and 1999

Interannual variability of the upper layers of the tropical Atlantic is described based on in situ data. An objective analysis used all available temperature observations of the upper tropical Atlantic between 1979 and 1999 to construct a 4D database. Wind data are used to investigate potential mechanisms which might explain the observed variability. Four remarkable events are described: 1983–1984, 1988–1990, 1994–1995 and 1997–1998. Three of them are characterised as equatorial (1983–1984, 1994–1995, and 1997–1998). The 1988–1990 event is a basin-wide phenomenon which does not involve the same mechanisms as the other three. Results of statistical decomposition in empirical orthogonal functions (EOFs) are discussed. There is no evidence of an inter-hemispheric mode on the depth of the 20?°C-isotherm (D20) and heat content comparable to the observed mode for sea surface temperature (SST) fields. Most energetic patterns for D20 and heat content are dominated by the stronger variability in the northern part of the basin. Influences of other climate signals are investigated. Correlations between the winter NAO (North Atlantic Oscillation) index and our standard variables is marginally significant. A positive NAOW (North Atlantic Oscillation of Winter) is associated with SST cooling in a latitude band between 10°N and 20°N. When applied to the El-Niño index, correlations are much more significant. We found two scales of maximum correlation: at the four month lag after the El-Niño mature phase when the thermocline slope and zonal heat content gradient are maximum along the equator, and at the ten month lag after the mature phase of El-Niño when the thermocline slope weakens and the equatorial gradient of heat content vanished. The correlation with a zonal wind index (average between 30°W–35°W and 2°N–2°S) has been computed. Correlation is maximum at the six month lag when the thermocline slope and the zonal heat content gradient are maximum in the equatorial band. This “Atlantic Niño” mode is influenced by the Pacific Ocean's variability and reaches a maximum one year after a warm event in the eastern Pacific.     

Interannual linkage between Arctic/North Atlantic Oscillation and tropical Indian Ocean precipitation during boreal winter

In the study authors analyzed the interannual relationship between the Arctic Oscillation (AO)/North Atlantic Oscillation (NAO) and the tropical Indian Ocean (TIO) precipitation in boreal winter for the period 1979–2009. A significant simultaneous teleconnection between them is found. After removing the El Niño/Southern Oscillation and Indian Ocean dipole signals, the AO/NAO and the TIO precipitation (0°–10°S, 60°–80°E) yield a correlation of +0.56, which is also consistent with the AO/NAO-outgoing longwave radiation correlation of ?0.61. The atmospheric and oceanic features in association with the AO/NAO-precipitation links are investigated. During positive AO/NAO winter, the Rossby wave guided by westerlies tends to trigger persistent positive geopotential heights in upper troposphere over about 20°–30°N and 55°–70°E, which is accompanied by a stronger Middle East jet stream. Meanwhile, there are anomalous downward air motions, strengthening the air pressure in mid-lower troposphere. The enhanced Arabian High brings anomalous northern winds over the northern Indian Ocean. As a result the anomalous crossing-equator air-flow enhances the intertropical convergence zone (ITCZ). On the other hand, the anomalous Ekman transport convergence by the wind stress curl over the central TIO deepens the thermocline. Both the enhanced ITCZ and the anomalous upper ocean heat content favor in situ precipitation in the central TIO. The AO/NAO-TIO precipitation co-variations in the IPCC AR4 historical climate simulation (1850–1999) of Bergen Climate Model version 2 were investigated. The Indian Ocean precipitation anomalies (particularly the convective precipitation along the ITCZ), in conjunction with the corresponding surface winds and 200 hPa anticyclonic atmospheric circulation and upper ocean heat contents were well reproduced in simulation. The similarity between the observation and simulation support the physical robustness of the AO/NAO-TIO precipitation links.