Anthropogenic footprints are invading global habitats of Indo-Pacific humpback dolphins

As ecologically fragile areas,coastal zones are affected by both anthropogenic activities and climate change.However,the impacts of these factors on large nearshore mammals,such as Indo-Pacific humpback dolphins(IPHDs,Sousa chinensis),are poorly understood.Here,modeling revealed that the suitable habitats of IPHDs are affected mainly by the sea surface temperature(SST),and the habitat suitability decreases as the distance to the nearest coastline increases.In addition,anthropogenic activities involving demersal fishing,contamination and shipping have narrowed IPHD habitats and reduced the habitat suitability.We found that climate change will further narrow suitable habitats located farther than 7 km from coastlines and trigger habitat losses in the eastern Taiwan Strait by 2090-2100 under the Representative Concentration Pathway(RCP)8.5 scenario.The projected decreases in habitat suitability and area emphasize the urgency of establishing connected marine protected areas(MPAs)while considering climate change,intergovernmental cooperation,and public involvement.

Variation of Indo-Pacific upper ocean heat content during 2001–2012 revealed by Argo

Understanding of the temporal variation of oceanic heat content （OHC） is of fundamental importance to the prediction of climate change and associated global meteorological phenomena. However, OHC characteristics in the Pacific and Indian oceans are not well understood. Based on in situ ocean temperature and salinity profiles mainly from the Argo program, we estimated the upper layer （0-750 m） OHC in the Indo-Pacific Ocean （40°S-40°N, 30°E-80°W）. Spatial and temporal variability of OHC and its likely physical mechanisms are also analyzed. Climatic distributions of upper-layer OHC in the Indian and Pacific oceans have a similar saddle pattern in the subtropics, and the highest OHC value was in the northern Arabian Sea. However, OHC variabilities in the two oceans were different. OHC in the Pacific has an east-west see-saw pattern, which does not appear in the Indian Ocean. In the Indian Ocean, the largest change was around 10°S. The most interesting phenomenon is that, there was a long-term shift of OHC in the Indo-Pacific Ocean during 2001-2012. Such variation coincided with modulation of subsurface temperature/salinity. During 2001-2007, there was subsurface cooling （freshening） nearly the entire upper 400 m layer in the western Pacific and warming （salting） in the eastern Pacific. During 2008-2012, the thermocline deepened in the western Pacific but shoaled in the east. In the Indian Ocean, there was only cooling （upper 150 m only） and freshening （almost the entire upper 400 m） during 2001-2007. The thermocline deepened during 2008-2012 in the Indian Ocean. Such change appeared from the equator to off the equator and even to the subtropics （about 20°N/S） in the two oceans. This long-term change of subsurface temperature/salinity may have been caused by change of the wind field over the two oceans during 2001-2012, in turn modifying OHC.

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.

India and the Indo-Pacific Strategy Vision： Orientation, Involvement and Limits

In 2017, the Trump administration formally articulated its vision for the Indo-Pacific strategy, replacing "Asia-Pacific" with"Indo-Pacific"in policy papers and taking measures to promote the realization of an "Indo-Pacific dream". This represents a significant adjustment in US regional policies. An important power in the Indian Ocean region, India is perceived as key to the successful implementation of this Indo-Pacific strategy. Generally speaking, the current Indian government and strategy circle actively support the upgrading of the"Indo-Pacific"concept from a geographical and academic term to a US vision for foreign strategies, anticipating that India could garner significant strategic benefits from it. Given this, New Delhi will continually adapt its foreign policies to the US Indo-Pacific strategy and may even direct the development of the strategy to counter the Belt and Road Initiative, work with other nations to balance China's influence and finally make the rise of India as a great power a reality. Nonetheless, the Indo-pacific strategy is in its early stages, and the content is not completely pro-India currently. On top of this India is still skeptical of the US and will proceed cautiously, leaving room for maneuver in the future,fully tapping into the benefits of the Indo-Pacific strategy and avoiding direct confrontation with China.

Upper Ocean Hydrology in the Indo-Pacific Warm Pool During the Late Holocene,Early Holocene and Last Glacial Maximum

We examined sediment samples from twenty-four stations in the Indo-Pacific warm pool(IPWP)region. Our objective is to provide a better understanding of changes in the IPWP and related tropical climatic phenomena such as East Asian-Australian monsoon and El Ni(?)o-Southern Oscillation(ENSO),through improving spatial coverage of proxy records.In order

A HOMOGENEOUS MODEL OF UPPER LAYER CIRCULATION IN INDO-PACIFIC REGION

A homogeneous model is proposed to study the upper layer circulation in the Indo-Pacific region,the sources of the Indonesian throughflow (TF) and the North Equatorial Countercurrent (NECC), and the relations of the the with the North Equatorial Current (NEC) and the South Equatorial Current (SEC). The results revealed that the upper layer circulaton, as part of the Pacific Ocean general circulation, is mainly controlled by geostrophic balance; that the NECC’s volume transport is mainly sup plied by the NEC, and its variation has closer relation to the NEC than the SEC; that the TF, whose volume transport is jointly supplied by the NEC through the Mindanao Current (MC) and the SEC, with the NEC being the first source, has significant influence on the circulation structure; and that a large Celebes Sea cyclonic circulation not mentioned elsewhere so far, exists in the calculated results.

India＇ s Advance East Strategy and Its Indo-Pacific Diplomacy

India's eastward advancement began in the early 1990s. It was then called the"Look East"policy, and was later upgraded in name to the"Act East"policy in 2014. Over the past 25 years, India's"Advance East"strategy has continued to expand, undergoing a compound evolution and upgrade from economy to security, from bilateral to multilateral, from the ASEAN region to East Asia and further onto the Asia-Pacific region,which has been reflected in the rise in India's national strength and regional influence, more and more become an important pillar in India's diplomatic strategy. Nonetheless, the traditional development trends of India's eastward advancement are being affected by the newly emerging Indo-Pacific diplomacy strategies and achievements. India's Indo-Pacific diplomacy was born out of its Advance East strategy, though not limited to advancement east; the core demand of India has always been to merge into the Asia-Pacific region. In other words, India's Advance East strategy is an important pivot for its Indo-Pacific diplomacy. The reliance of India's Indo-Pacific diplomacy on major power diplomacy has impacted the core position of ASEAN in its Advance East strategy, while the element of containing China in India's Indo-Pacific diplomacy will dilute its intention to cooperate with China. This is also manifested in its Advance East strategy.

The Indo-Pacific Strategy of the United States from Russia’s Strategic Perspective

The Trump administration of the United States has accelerated the advancement of the‘‘open and free Indo-Pacific’,strategy since 2017.From a geopolitical point of view and in terms of its national interests,Russia has generally been critical of this strategy,believing it has posed certain challenges to its“Pivot to the East”strategy.Meanwhile,Russia is rejoicing for not being the primary target of US containment in the region and has sensed a new opportunity for exercising its Asia-Pacific diplomacy in the context of the Indo-Pacific strategy.Based on this situation,Russia has made a flexible and pragmatic policy response to it.However,Russia will inevitably face many restraints.In the future,Russia will seek to maximize its strategic interests on the basis of adhering to its inherent principles of Asia-Pacific diplomacy.

Early divergence and differential population histories of the Indo-Pacific humpback dolphin in the Pacific and Indian Oceans

The currently recognized Indo-Pacific humpback dolphin occurs in estuaries and surrounding shallow waters from the South China Sea to the Asian coast of the Indian Ocean.However,a recent study suggested that the humpback dolphin from the Bay of Bengal may represent a distinct phylogenetic species.In this study,we sequenced 915-bp mtDNA segments from five geographic populations in both Chinese and Thai waters;together with previously published sequences,these data revealed that the ancestral Indo-Pacific humpback dolphin might have split during the transition from the Oligocene to Miocene(23.45 Mya,95%HPD:16.65–26.55 Mya),and then dispersed along the Pacific and Indian Ocean coasts of Asia.Genetic differentiation was detected between most of the examined populations,except for only a few pairwise populations in the northern South China Sea.Genetic differentiation/distance between the humpback dolphins from the northern and southern South China Sea met the sub-species threshold value proposed for marine mammals,whereas that between the humpback dolphins in the Pacific and the Indian Ocean was above the species threshold.Bayesian inference of historic gene flow indicated low but constant northward gene flow along the Indian Ocean coast;however,there was a recent abrupt increase in gene flow in the Pacific region,likely due to the shortening coastline at the low stand of sea level.Our results revealed that the current taxonomic classification of Indo-Pacific humpback dolphins may not reflect their phylogeography.

The intestinal microbiome of an Indo-Pacific humpback dolphin(Sousa chinensis)stranded near the Pearl River Estuary,China

The mammalian intestinal microbiome is critical for host health and disease resistance.However,the cetacean intestinal microbiota remains relatively unexplored.By using high-throughput 16S rRNA gene sequencing,we analyzed intestinal bacterial samples from an Indo-pacific humpback dolphin(Sousa chinensis)stranded near the Pearl River Estuary in China.The samples included 3 anatomical regions(foregut,midgut,and rectum)and 2 anatomical locations(content and mucus).Our analyses revealed that the dolphin intestinal bacteria contained 139 operational taxonomic units(OTUs),dominated at the phyla level by Firmicutes(47.05%in the content;94.77%in the mucus),followed by Bacteroidetes(23.63%in the content;1.58%in the mucus)and Gammaproteobacteria(14.82%in the content;2.05%in the mucus).The intestinal bacteria had a small core community(15 OTUs,accounting for 99.74%of the reads),some of which could be potentially pathogenic to both human and dolphins.As an alternative to sampling the dolphin intestinal bacteria,fecal sampling could be used.Additionally,function potentials such as,xenobiotics biodegradation,beta-lactam resistance,and human disease-related pathways,were detected in the dolphin intestinal bacteria.These findings provide the first baseline knowledge of the intestinal microbiome of the Indo-Pacific humpback dolphin,which may offer new insights into cetacean conservation by using microbial surveillance.

Whistle signal variations among three Indo-Pacific humpback dolphin populations in the South China Sea:a combined effect of the Qiongzhou Strait’s geographical barrier function and local ambient noise?

Geographic variations in the dolphin whistles could be useful in assessing association and isolation among populations.Whistle of free-ranging Indo-Pacific humpback dolphins(Sousa chinensis)among the Pearl River Estuary(PRE),Leizhou Bei(LZB)and Sanniang Bay(SNB)populations were investigated.A total of 2850 whistles with legible fundamental contour were extracted and 15 acoustic parameters were measured.Contrary to SNB,PRE and LZB had the same relative proportion of tonal type compositions with flat and sine representing the most frequent types.The generalized linear model analysis showed significant acoustic difference among populations and tonal types.All frequency parameters in SNB were significantly higher than those in PRE and LZB,where no significant variation was observed in most of the parameters either at the population level or within each tonal type.Canonical discriminant functions analysis showed a smaller difference between PRE and LZB than between PRE and SNB and between LZB and SNB.Compared with previous recordings,recent recordings demonstrated a consistent pattern of becoming higher in whistle frequency parameters in both LZB and SNB populations,suggesting that noise pollution in LZB and SNB increasing with time according to the acoustic niche hypothesis.Dolphin whistle’s geographic variations could be shaped by the combined function of the geographical barrier function of the Qiongzhou strait and local ambient noise.Considering the isolated condition and the relatively smaller population size of the humpback dolphin in the SNB,more effective and proactive conservation actions should be taken to prevent the extinction of small populations.

FOIP 2.0: The Evolution of Japan’s Free and Open Indo-Pacific Strategy

Introduction Since Japanese Prime Minister Shinzo Abe launched a new foreign policy doctrine at the opening session of the Sixth Tokyo International Conference on African Development(TICADⅥ)on August 27,2016,Japan’s"Free and Open Indo-Pacific"strategy,or FOIP,has stimulated a broader debate on the future Indo-Pacific regional order.

The Trend of Indo-Pacific Strategy and its Impact on the U.S.-Japan Alliance——Creating and evolving of dual ambiguity, dual assurance and dual check strategies

In recent years, since the Obama Administration, the policy discussions on the Indo-Pacific region have gradually moved from conceptualization to strategy. The Indo-Pacific strategy is established during the Trump Administration, in which, Japan played a leading role. The Indo-Pacific strategy is advanced jointly by the United States and Japan. In this process, the three characteristics of dual ambiguity, dual assurance and dual check are taking shape, which has a compound influence on the Japan-U.S. alliance and showed the interaction between tension and synergy. Compared with the Asia-Pacific strategy, building a huge Indo-Pacific strategy requires more costs, and Indo-Pacific countries are paying close attention to its development trend.

Linkage of the Decadal Variability of Extreme Summer Heat in North China with the IPOD since 1981

Extreme summer heat can have serious socioeconomic impacts in North China.Here,we explore the decadal variability of the number of extreme heat days in early-to-mid summer(June and July)and a related potential mechanism consistent with the major seasonal occurrence period of extreme heat events in North China(NCSH).Observational analyses show significant decadal variability in NCSH for 1981–2021,potentially linked to the Indo-Pacific warm pool and Northwest Pacific Ocean dipole(IPOD)in early-to-mid summer.Dynamic diagnostic analysis and the linear baroclinic model(LBM)show that the positive IPOD in early-to-mid summer can excite upward vertical wind anomalies in the South China-East China Sea region,shifting the position of the western Pacific subtropical high(WPSH)to the east or weakening the degree of its control of the South China-East China Sea region,thus generating a positive geopotential height quadrupole(EAWPQ)pattern in the East Asia-Northwest Pacific region.Subsequently,the EAWPQ can cause air compression(expansion)over North China by regulating the tropospheric thickness anomalies in North China,thus increasing(decreasing)NCSH.Finally,an empirical model that incorporates the linear trend can better simulate the decadal NCSH compared to an empirical model based solely on the IPOD index,suggesting that the decadal variability of NCSH may be a combined contribution of the decadal IPOD and external linear forcing.

Interdecadal Change in the Interannual Variability of South China Sea Summer Monsoon Intensity

The interdecadal change in the interannual variability of the South China Sea summer monsoon(SCSSM)intensity and its mechanism are investigated in this study.The interannual variability of the low-level circulation of the SCSSM has experienced a significant interdecadal enhancement around the end of the 1980s,which may be attributed to the interdecadal changes in the evolution of the tropical Indo-Pacific sea surface temperature(SST)anomalies and their impacts on the SCSSM.From 1961 to 1989,the low-level circulation over the South China Sea is primarily affected by the SST anomalies in the tropical Indian Ocean via the mechanism of Kelvin-wave-induced Ekman divergence.While in 1990 to 2020,the impacts of the summer SST anomalies in the Maritime Continent and the equatorial central to eastern Pacific on the SCSSM are enhanced,via anomalous meridional circulation and Mastuno-Gill type Rossby wave atmospheric response,respectively.The above interdecadal changes are closely associated with the interdecadal changes in the evolution of El Niño–Southern Oscillation(ENSO)events.The interdecadal variation of the summer SST anomalies in the developing and decaying phases of ENSO events enhances the influence of the tropical Indo-Pacific SST on the SCSSM,resulting in the interdecadal change in the interannual variability of the SCSSM.

巴基斯坦大国外交调整透视

Pakistan,China’s all-weather strategic cooperative partner,has recently undergone a significant adjustment in its major country diplomacy,particularly in its policies toward the United States and Russia.The triangular relationship among Pakistan,the United States,and Russia has changed from a previous severely unbalanced state,in which the Pakistan–United States relationship is stronger and the Pakistan–Russia relationship is weaker,to a relatively dynamic equilibrium state in which the Pakistan–United States relationship declines while the Pakistan–Russia relationship rises.At the same time,although Pakistan’s policy toward India and China has continued the central tone of Pakistan–India confrontation and Pakistan–China friendship,several new changes and trends have emerged.While Pakistan–India relations are generally tense,Pakistan has performed active management of crises to keep conflicts from getting out of control and leading to war or other combat.Pakistan has long actively maintained friendly relations with China and is focusing on promoting practical cooperation in the form of the China–Pakistan Economic Corridor.The current round of adjustment to Pakistan’s major country diplomacy stems from multiple internal and external factors.Externally,the United States has begun to promote its“Indo-Pacific”strategy,and the Ukraine crisis has played a catalytic role as well.Internally,these changes can mainly be ascribed to the major changes in Pakistan’s leadership,as well as the country’s severe domestic political and economic challenges,as well as the urgent need for external support,especially from major countries,to improve the domestic situation.Pakistan’s major country diplomacy adjustment has had relatively obvious geopolitical and security impacts so far at the global and regional levels,but it is limited by the international situation,its own strategic orientation,and national conditions.Pakistan’s relations with major countries continue to face structural challenges.

俄乌冲突背景下“北约印太化”的表现、原因及影响

“北约印太化”是北约基于“冷战思维”扩展其全球影响力的集中表现。其实质是在俄乌冲突外溢效应的影响下,美国、北约的欧洲盟国以及日本、韩国等“印太地区伙伴”基于各自利益所做出的战略选择。在欧洲盟国看来,面对当下与日俱增的安全压力需要提升自身的防卫能力并且加强同美国的协调,美国则借机鼓励盟友分担更多防务以实现战略收缩,将更多力量集中到印太地区,同时联通大西洋和印太两个地区的盟伴体系以助力与中国的战略博弈。通过分析美国、北约的欧洲盟国和其“印太地区伙伴”国家各自的战略认知和动机,可以更加全面深刻地认识“北约印太化”的原因与趋势,从而更好地应对其可能对中国造成的影响。

A Comparison of Polar Vortex Response to Pacific and Indian Ocean Warming

During recent decades, the tropical Indo-Pacific Ocean has become increasingly warmer. Meanwhile, both the northern and southern hemispheric polar vortices （NPV and SPV） have exhibited a deepening trend in boreal winter. Although previous studies have revealed that the tropical Indian Ocean warming （IOW） favors an intensifying NPV and a weakening SPV, how the tropical Pacific Ocean warming （POW） influences the NPV and SPV remains unclear. In this study, a comparative analysis has been conducted through ensemble atmospheric general circulation model （AGCM） experiments. The results show that, for the Northern Hemisphere, the two warmings exerted opposite impacts in boreal winter, in that the IOW intensified the NPV while the POW weakened the NPV. For the Southern Hemisphere, both the IOW and POW warmed the southern polar atmosphere and weakened the SPV. A diagnostic analysis based on the vorticity budget revealed that such an interhemispheric difference in influences from the IOW and POW in boreal winter was associated with different roles of transient eddy momentum flux convergence between the hemispheres. Furthermore, this difference may have been linked to different strengths of stationary wave activity between the hemispheres in boreal winter.

“印太战略”与“全球英国”战略交汇下的日英安全合作

Japan-UK security cooperation has been deepening as the Indo-Pacific Strategy has converged with Global Britain,which has become strongly Indo-Pacific-oriented.In terms of their cooperation on security,the two countries have close security interactions,high-level security consultations,numerous mechanisms on security cooperation,frequent defense cooperation and exchanges between forces,and cooperation geared at a response to the Korean nuclear issue.In particular,Japan and the UK regard Indo-Pacific security as the strategic focus of their cooperation,and this underscores the rules-based international order.There are multiple motivations for Japan and the UK to strengthen their security cooperation,and the deepening of their security cooperation in the Indo-Pacific region is to a great extent due to strategic factors,including responding to the US strategic adjustment,Japan and Britain’s respective proactive strategic demands,the improving strategic positions of the Indopacific region,their seeking to shape the regional order in the Indo-Pacific,and so on.Despite facing challenges,Japan-UK security cooperation is continuously strengthening against a background of deepening strategic convergence between the two countries and great power competition.

An aftereffect of global warming on tropical Pacific decadal variability

Studies have shown that global warming over the past six decades can weaken the tropical Pacific Walker circulation and maintain the positive phase of the Interdecadal Pacific Oscillation(IPO).Based on observations and model simulations,another afteref fect of global warming on IPO is found.After removing linear trends(global warming signals)from observations,however,the tropical Pacific climate still exhibited some obvious dif ferences between two IPO negative phases.The boreal winter(DJF)equatorial central-eastern Pacific sea surface temperature(SST)was colder during the 1999–2014 period(P2)than that during 1961–1976(P1).This diff erence may have been a result of global warming nonlinear modulation of precipitation;i.e.,in the climatological rainy region,the core area of the tropical Indo-western Pacific warm pool receives more precipitation through the"wet-get-wetter"mechanism.Positive precipitation anomalies in the warm pool during P2 are much stronger than those during P1,even after subtracting the linear trend.Corresponding to the dif ferences of precipitation,the Pacific Walker circulation is stronger in P2 than in P1.Consequent easterly winds over the equatorial Pacific led to a colder equatorial eastern–central Pacific during P2.Therefore,tropical Pacific climate dif ferences between the two negative IPO phases are afteref fects of global warming.These afteref fects are supported by the results of coupled climate model experiments,with and without global warming.