Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(EN...Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(ENSO)on summer precipitation in China.The inverse phase spatial distribution of sea surface temperature anomalies(SSTAs)in the southwest and northeast of the southern Indian Ocean is defined as the SIOD.Positive SIOD events(positive SSTAs in the southwest,negative SSTAs in the northeast)are associated with La Niña events(Central Pacific(CP)type),while negative SIOD events(negative SSTAs in the southwest,positive SSTAs in the northeast)are associated with El Niño events(Eastern Pacific(EP)type).Both SIOD and ENSO have certain impacts on summer precipitation in China.Precipitation in the Yangtze River basin decreases,while precipitation in southern China increases during pure positive SIOD(P_PSIOD)events.During pure negative SIOD(P_NSIOD)events,the changes in precipitation are exactly the opposite of those during P_PSIOD events,which may be due to differences in the cross-equatorial flow in the southern Indian Ocean,particularly in low-level Australian cross-equatorial flow.When positive SIOD and CP-type La Niña events occur simultaneously(PSIOD+La_Niña),precipitation increases in the Yangtze-Huaihe River basin,while it decreases in northern China.When negative SIOD and EP-type El Niño events occur simultaneously(NSIOD+El_Niño),precipitation in the Yangtze-Huaihe River basin is significantly lower than during P_NSIOD events.This is caused by differences in water vapor originating from the Pacific Ocean during different events.展开更多
Kidney transplantation(KT)accounts for nearly three-fourths of organ transplants in India,with living donors contributing to 82%of cases.Induction immunosuppression is essential to optimize initial immunosuppression,r...Kidney transplantation(KT)accounts for nearly three-fourths of organ transplants in India,with living donors contributing to 82%of cases.Induction immunosuppression is essential to optimize initial immunosuppression,reduce acute rejections,and enable tailored use of maintenance agents.Rabbit anti-thymocyte globulin(rATG)and interleukin-2 receptor anatagonists(IL-2RA/IL-2RBs)are the most widely used induction therapies.However,data on induction practices across India are limited.To evaluate induction immunosuppression practices across KT centers in India and establish a consensus for different subsets of KT recipients.A nationwide online survey was conducted by the Indian Society of Organ Transplantation(ISOT)among its members(400 KT centers).Responses were analyzed to assess induction practices across diverse donor types,age groups,and immunological risk profiles.Heterogeneity in practices prompted consensus building using a modified Delphi process.Literature review and expert panel discussions(April 2024)were followed by structured voting,and 16 consensus statements were finalized.Of 400 centers approached,254 participated.rATG was the most commonly used induction therapy,followed by IL-2RBs;alemtuzumab was least used.Significant heterogeneity was observed in type,dose,and duration of induction therapy.Consensus recommendations were framed:rATG for high immunological risk recipients and deceased donor KTs;IL-2RB or low-dose rATG for low immunological risk;rituximab in ABOincompatible KTs;and tailoring based on age,diabetes,donor type,infection risk,and affordability.This first ISOT consensus provides 16 India-specific statements on induction therapy in KT.It emphasizes risk-stratified,evidenceinformed,and context-appropriate induction strategies,supporting standardization of care across the country.展开更多
The Indonesian Throughflow(ITF)plays important roles in global ocean circulation and climate systems.Previous studies suggested the ITF interannual variability is driven by both the El Niño-Southern Oscillation(E...The Indonesian Throughflow(ITF)plays important roles in global ocean circulation and climate systems.Previous studies suggested the ITF interannual variability is driven by both the El Niño-Southern Oscillation(ENSO)and the Indian Ocean Dipole(IOD)events.The detailed processes of ENSO and/or IOD induced anomalies impacting on the ITF,however,are still not clear.In this study,this issue is investigated through causal relation,statistical,and dynamical analyses based on satellite observation.The results show that the driven mechanisms of ENSO on the ITF include two aspects.Firstly,the ENSO related wind field anomalies driven anomalous cyclonic ocean circulation in the western Pacific,and off equatorial upwelling Rossby waves propagating westward to arrive at the western boundary of the Pacific,both tend to induce negative sea surface height anomalies(SSHA)in the western Pacific,favoring ITF reduction since the develop of the El Niño through the following year.Secondly,the ENSO events modulate equatorial Indian Ocean zonal winds through Walker Circulation,which in turn trigger eastward propagating upwelling Kelvin waves and westward propagating downwelling Rossby waves.The Rossby waves are reflected into downwelling Kelvin waves,which then propagate eastward along the equator and the Sumatra-Java coast in the Indian Ocean.As a result,the wave dynamics tend to generate negative(positive)SSHA in the eastern Indian Ocean,and thus enhance(reduce)the ITF transport with time lag of 0-6 months(9-12 months),respectively.Under the IOD condition,the wave dynamics also tend to enhance the ITF in the positive IOD year,and reduce the ITF in the following year.展开更多
Extraterrestrial phenomena have influenced Earth’s processes throughout geological history.Evaluating the impact of extraterrestrial material on the environment is crucial for understanding the evolution of Earth and...Extraterrestrial phenomena have influenced Earth’s processes throughout geological history.Evaluating the impact of extraterrestrial material on the environment is crucial for understanding the evolution of Earth and life.This study incorporates the investigation of micrometeorites(MMs),abundant cosmic materials on Earth,to understand their influence on the chemical composition and biogeochemistry of the ocean.Comprehensive etching and flux analyses reveal that∼95%of cosmic spherules(CSs)entering seawater are etched or wholly dissolved,supplying nutrients to phytoplankton.Barred spherules show the highest degree of etching(∼19%),followed by porphyritic(∼17%),glass(∼15%),cryptocrystalline(∼12%),scoriaceous(∼10%),G-type(∼9%),and I-type(∼6%).Annually,∼3080 tonnes(t)of olivine from MMs dissolve into seawater,contributing∼495 t of Mg^(2+),∼1110 t of Fe^(2+),and∼1928 t of silicic acid.This signifies that over the Indian Ocean’s∼40 Myr history,∼23 Gt of olivine from CSs has dissolved,providing nutrients to seawater and sequestering∼7 Gt of CO_(2).The world ocean during this time has sequestered∼35 Gt of CO_(2),with fluctuations influenced by extraterrestrial activity.For instance,the Veritas event,lasting∼1.5 Myr,sequestered∼6 Gt of CO_(2)from the atmosphere.A robust flux calculation based on∼2 t of deep-sea sediments from 3610 MMs provides a more accurate estimate of the time-averaged flux of∼229 t yr^(−1).These comprehensive analyses reveal MM’s original characteristics,post-deposition processes,geological record and their overall impact on Earth’s marine environments,thereby contributing to our knowledge of the interconnection between terrestrial and extraterrestrial processes.展开更多
Tanzania is mainly subject to a bimodal rainfall pattern,characterized by two distinct seasons:the long rains,occurring from March to May,and the short rains,which typically take place from October to December(OND).Sh...Tanzania is mainly subject to a bimodal rainfall pattern,characterized by two distinct seasons:the long rains,occurring from March to May,and the short rains,which typically take place from October to December(OND).Short rains are usually less intense but still significantly influence local agriculture.Therefore,with station-based observations and reanalysis data,the current paper examines the interannual variability of OND precipitation in Tanzania from 1993 to 2022 and explores the possible impacts from El Niño–Southern Oscillation(ENSO)and the Indian Ocean Dipole(IOD)as well as the mechanisms.It is found that the Tanzania OND precipitation is above(below)normal in 1997,2006,2011,and 2019(1993,1998,2005,and 2016).The composite difference between wet(dry)years and the climatology indicates that the anomalous lower-level convergence(divergence)and upward(downward)motion are the critical circulation characters for above(below)precipitation.Further analysis indicates ENSO and the IOD are the two main oceanic systems modulating OND precipitation in Tanzania.El Niño and a positive IOD could induce easterly anomalies and weaken the Walker circulation over the Indian Ocean,consequently leading to lower-level convergence in water vapor flux,upward anomalies,and more than normal precipitation in Tanzania.In contrast,La Niña and a negative IOD produce opposite circulation anomalies and less than normal precipitation over Tanzania.Moreover,through partial correlation and Generalized Equilibrium Feedback Analysis,the individual contributions of ENSO and the IOD to circulation are investigated.It is found that although both the IOD and ENSO impact the Walker circulation,the feedback to the IOD is stronger than ENSO.These results provide critical insights into the oceanic drivers and their mechanistic pathways underlying precipitation anomalies in Tanzania.展开更多
El Niño is frequently followed by La Niña,while La Niña tends to sustain into the next year or even longer,exhibiting a notable phase transition asymmetry(TA)of El Niño-Southern Oscillation(ENSO).T...El Niño is frequently followed by La Niña,while La Niña tends to sustain into the next year or even longer,exhibiting a notable phase transition asymmetry(TA)of El Niño-Southern Oscillation(ENSO).This study explores the potential influences of tropical Indian Ocean(TIO)decadal variability on TA based on a comparative analysis of the relationship between the TIO sea surface temperature anomalies(SSTA)and ENSO during different periods.Generally,the TIO SSTA strengthened TA before the 1980s,corresponding to a highly positive relationship between the whole TIO SSTA and ENSO.However,the weakening effect was exhibited after the 1980s when the correlation diminished.After the late 1990s,ENSO was only positively correlated with western TIO,with the westerly exhibit of the SSTA center leading to smaller impacts on TA.Moreover,TIO SSTA tends to weaken TA by promoting the transition efficiency of La Niña,while bringing little effect on that of El Niño.Physically,compared to the mid-1970s,TIO SSTA triggered westerly wind anomalies during the autumn and winter of the La Niña development phase in the central equatorial Pacific in the late 1990s,which sped up the decay of La Niña.It then regenerated westerly anomalies in the following winter,facilitating the development of El Niño.This study quantifies the impact of the TIO SSTA on TA in seasonal signals and investigates the decadal variability of such influence,aiming to further understand phase transition asymmetry and offer valuable insights for the prediction of multi-year La Niña.展开更多
In the author list,the corresponding author indicator(*)was inadvertently omitted from HOU Zengqian’s name.This has now been corrected to:“HOU Zengqian¹,*”.The online version of this article was corrected.
In recent years, traditional rice landraces have gained increasing attention among consumers, scientists, and nutritionists because of their nutritional and therapeutic value. The diverse rice gene pool of the Indian ...In recent years, traditional rice landraces have gained increasing attention among consumers, scientists, and nutritionists because of their nutritional and therapeutic value. The diverse rice gene pool of the Indian subcontinent is bestowed with indigenous rice types augmented with nutrients and phytochemicals. Landraces high in resistant starch and dietary fiber contribute to gut health and help prevent gastrointestinal disorders, whereas those with high-quality protein contents, such as glutelin and lysine, all-trans retinoic acid, as well as iron and zinc contents(even in polished rice), play a vital role in the alleviation of malnutrition and hidden hunger. Metabolomic studies have revealed the presence of novel bioactive molecules, including tocols(e.g., gamma-tocotrienol and alpha-tocopherol), phytosterols(e.g., campestrol, beta-sitosterol, and stigmasterol), phenolic acids(e.g., 2-methoxy-4-vinylphenol, 4-vinylphenol, 3,5-di-tert-butylphenol, 2,4-di-tert-butylphenol, ionol, and 2,6-di-tert-butylphenol), flavonoids [e.g., flavonolignans tricin 4′-O-(threo-β-guaiacylglyceryl) ether and tricin 4′-O-(erythro-β-guaiacylglyceryl) ether], anthocyanins(e.g., delphinidin and cyanidin), carotenoids(e.g., 7,7′,8,8′-tetrahydrolycopene and 1-hydroxylycopene), diterpenoids(e.g., sugiol), vitamin D3(a secosteroid), and bioactive vitamin D(e.g., calcitriol). These bioactive phytochemicals endow Indian rice landraces, rich in antioxidants, with antiphlogistic, antineoplastic, cardiac risk preventive, antiviral, and antitubercular activities, confirming their use in traditional Indian medicine. Furthermore, Indian landraces with a low glycemic index may benefit the Asian Indian phenotype, which is characterized by clinical anomalies such as insulin resistance, dyslipidemia(reduced high-density lipoprotein levels), and high dietary glycemic load. Therefore, the conservation of India's traditional rice varieties is vital for both sustainable agriculture and improving global health.展开更多
The current investigation focuses on intertwined relationships of ecology and aquaculture for the benefit of farmers involved in fish farming practices.The study evaluated glucosinolate reduction in black,brown,and wh...The current investigation focuses on intertwined relationships of ecology and aquaculture for the benefit of farmers involved in fish farming practices.The study evaluated glucosinolate reduction in black,brown,and white mustard meals as fish feed ingredients for Indian Major Carps.Fish were fed with 10%mustard meal-supplemented diets in three forms:Raw(R),Anti-nutritional Rich(AR),and Anti-nutritional Lowered(AL),alongside a control group using floating feed.The three-month indoor experiment(September-November 2023)was conducted in FRP tanks with triplicate treatments.Blood analysis revealed compromised health in AR-fed carps,with reduced hemoglobin levels in rohu,catla and mrigal and elevated total leukocyte counts indicating inflammation in all the three carps studied here.Liver function was impaired in AR-fed fish,shown by increased alanine transaminase levels,highest in rohu followed by mrigal and catla.Histopathological examination of AR-fed carps liver tissue revealed necrotic spots,deformed hepatocytes,and significant vacuolation.In contrast,AL-fed fish demonstrated improved health parameters through Complete Blood Count analysis,liver function tests,and histo-pathological observations,suggesting successful reduction of anti-nutritional factors in the processed mustard meals.In near future,replacement of unprocessed seed meal with processed seed meal will lead to economic gains in fish farming.展开更多
On 14 January 2025,CAFIU Vice-President Ai Ping met with Pradeep Kumar Rawat,Ambassador of India to China.The two sides exchanged views on China-India relations as well as cultural and peopleto-people exchanges.
The unique features of the Equatorial Undercurrent(EUC)and relations to the Indian Ocean Dipole(IOD)highlight the complexity and importance of the tropical eastern Indian Ocean(EIO),yet the EUC dynamics and associated...The unique features of the Equatorial Undercurrent(EUC)and relations to the Indian Ocean Dipole(IOD)highlight the complexity and importance of the tropical eastern Indian Ocean(EIO),yet the EUC dynamics and associated physical-biogeochemical implications remain patchy.Here,mainly using in situ observations during April-May 2011,we provide direct evidence of the spring eastward EUC and its relations to the southward subsurface salty water and upwelling off Sumatra and reveal its biogeochemical responses.A strong eastward velocity of~1.2 m/s at a depth of 120 m near the equator along the meridional section of 90°E clearly indicates the EUC.The continuum of subsurface salty water from the equator to the offshore region off Sumatra generally shows the pathway and dynamic bridge role of the EUC.The southward shoaling of isotherms and isohalines near the upper boundary of thermocline in the region off Sumatra implies the occurrence of weak upwelling from the subsurface salty water;the early onset of southeasterly wind associated with the positive IOD might be responsible for this phenomenon.The EUC is important in driving the spatial variability of the oxygen minimum zone(OMZ)and subsurface chlorophyll a maximum(SCM)in the tropical EIO.In particular,the EUC may act as a source of O_(2),depressing the upward limit of the OMZ at the equator.Moreover,the eastward depressed EUC induces the downwelling of the OMZ and a deepened and weakened SCM from west to east along the equator.Influenced by EUC transport and upwelling,a southward extension of the OMZ with an uplifted oxycline occurred in the region off Sumatra,and a southward enhanced and shoaled SCM emerged.The results unraveled the dynamic linkages between the EUC and biogeochemical environments,constituting a considerable contribution to the understanding of the physical-biogeochemical-ecological interactions in the tropical EIO.展开更多
The present study of metabasalts was carried out to understand the mantle source and geodynamic setting of the Mahakoshal Group in the Central Indian Tectonic Zone.In this study,we present detailed field,petrography,a...The present study of metabasalts was carried out to understand the mantle source and geodynamic setting of the Mahakoshal Group in the Central Indian Tectonic Zone.In this study,we present detailed field,petrography,and whole rock geochemistry of the Mahakoshal metabasalts.The Mahakoshal metabasalts are sub-alkaline in nature and belong to the tholeiitic series of rocks.The variation in rareearth element patterns of metabasalts indicates the different degrees of partial melting at shallow as well as deeper depths.Further,Eu/Eu*varies from 0.8 to 1.1(except sample KP-144=0.3),Ce/Ce*varies from 0.97 to 1.05,showing no cerium anomaly,and Nb/Nb*ranges from 0.7 to 1.3(except KP-144=0.1).The magnesium number(Mg#)varies from 0.2 to 0.3,which is quite low,indicating the evolved nature of the metabasalts.The studied metabasalts show E-MORB to OIB-type affinities,which are placed in the trench-distal back-arc setting.The opening of the Mahakoshal Basin is due to retreating orogen in the accretionary orogen setting and is contemporaneous with the assembly of the Columbia Supercontinent(~2.1-1.8 Ga).Hence,field,petrographic,and geochemical signatures indicate that the Mahakoshal basin opened as a back-arc rift basin on the Bundelkhand Craton,and that metabasalts are derived from the mantle that underwent variable degrees of partial melting at different depths.展开更多
This study explores the impact of winter sea surface temperature(SST)anomalies in the Southern Indian Ocean on summer precipitation patterns in China,utilizing data from reanalysis sources and Coupled Model Intercompa...This study explores the impact of winter sea surface temperature(SST)anomalies in the Southern Indian Ocean on summer precipitation patterns in China,utilizing data from reanalysis sources and Coupled Model Intercomparison Project Phase 6(CMIP6)models.The results reveal that the Southern Indian Ocean Dipole(SIOD),characterized by contrasting SST anomalies in the northeast and southwest regions,acts as a predictor for Chinese summer precipitation patterns,namely floods in the south and drought in the north.In a positive SIOD event,the southwestern Indian Ocean exhibits warmer SSTs,while the northeastern region remains cooler.A negative SIOD event shows the opposite pattern.During the positive phase of the SIOD,the winter SST distribution strengthens the 850-hPa cross-equatorial airflow,generating a robust low-level westerly jet that enhances water vapor transport to the Bay of Bengal(BoB).These air-sea interactions maintain lower SSTs in the northeastern region,which significantly increase the land-sea temperature contrast in the Northern Hemisphere during spring and summer.This strengthened thermal gradient intensifies the southwest monsoon,establishing a strong convergence zone near the South China Sea and amplifying monsoon-driven precipitation in South China.Additionally,CMIP6 models,such as NorESM2-LM and NorCPM1,which accurately simulate the SIOD pattern,effectively capture the seasonal response of cross-equatorial airflow driven by SST anomalies of Southern Indian Ocean.The result highlights the essential role of cross-equatorial airflow generated by the SIOD in forecasting crossseasonal precipitation patterns.展开更多
Based on the reanalysis data of monthly mean sea surface temperature (SST) from British Hadley Center and ozone mass mixing ratio from National Aeronautics and Space Administration (NASA) during 1980-2015, two indexes...Based on the reanalysis data of monthly mean sea surface temperature (SST) from British Hadley Center and ozone mass mixing ratio from National Aeronautics and Space Administration (NASA) during 1980-2015, two indexes IOBI and IODI of the main modes characterizing SST changes in the tropical Indian Ocean——Indian Ocean Basin (IOB) and Indian Ocean Dipole (IOD) were calculated firstly, and then the correlation of SST anomaly (SSTA) in the tropical Indian Ocean and ozone mass mixing ratio in the stratosphere over East Asia from 1980 to 2015 was analyzed. Besides, the impact of SST changes in the tropical Indian Ocean on the distribution of ozone layer in East Asia was discussed. The results show that SST changes in the tropical Indian Ocean had significant effects on stratospheric ozone distribution in East Asia, and it was consistent with the temporal changes of IOB and IOD. IOBI and IODI had a certain correlation with stratospheric ozone changes in East Asia, with a particularly significant correlation in the lower stratosphere (70 hPa) and middle stratosphere (40 hPa) especially during spring and autumn.展开更多
The relationship between ENSO and Indian Ocean Dipole was discussed by using the data set of sea temperature from Scripps Institute of Oceanography, the air temperature at 1000hPa from the NCEP reanalysis data and the...The relationship between ENSO and Indian Ocean Dipole was discussed by using the data set of sea temperature from Scripps Institute of Oceanography, the air temperature at 1000hPa from the NCEP reanalysis data and the Nino3 index from the Climate Prediction Center （CPC） of U.S.A. during the period from 1955 to 2001. The results show that there exists a Dipole on the maximum temperature anomalous level （MTAL） in the Indian Ocean, which close relates to ENSO in the Pacific Ocean. During El Nino periods there are good relationships between ENSO and Indian Ocean Dipole which maximum correlation occurring when ENSO leads by one month, but in La Nina periods the relationship is not so good. The distribution of Dipole in Indian Ocean is from northeast to southwest, which one （west） pole in 65°E - 75°E, 6°S - 10°S and the other in 85°E - 95°E, 2°N - 6°N, which is different from that defined by Saij. The correlation coefficients of Nino3 index with temperature anomalies in the west/east poles on the MTAL are over 0.4 - 0.15, respectively. It is a main sea temperature system in the tropical Indian Ocean. However, in the surface layer from sea surface to the depth of 20 m - 30 m there is no such a dipole with opposite sea temperature anomalies in the NE and SW of tropical Indian Ocean. The SSTA in the NE might be influenced by the sensible exchange process because the evolution of sea and 1 000 hPa air temperature anomaly time series of the NE of tropical Indian Ocean is quite similar except those during 1962 - 1963 and 1986. The periods of Indian Ocean Dipole are shorter than that of ENSO, and about 1 to 6-year.展开更多
The variation in the Indian Ocean is investigated using Hadley center sea surface temperature（SST） data during the period 1958–2010.All the first empirical orthogonal function（EOF） modes of the SST anomalies（SST...The variation in the Indian Ocean is investigated using Hadley center sea surface temperature（SST） data during the period 1958–2010.All the first empirical orthogonal function（EOF） modes of the SST anomalies（SSTA） in different domains represent the basin-wide warming and are closely related to the Pacific El Ni o– Southern Oscillation（ENSO） phenomenon.Further examination suggests that the impact of ENSO on the tropical Indian Ocean is stronger than that on the southern Indian Ocean.The second EOF modes in different domains show different features.It shows a clear east-west SSTA dipole pattern in the tropical Indian Ocean（Indian Ocean dipole,IOD）,and a southwest-northeast SSTA dipole in the southern Indian Ocean（Indian Ocean subtropical dipole,IOSD）.It is further revealed that the IOSD is also the main structure of the second EOF mode on the whole basin-scale,in which the IOD pattern does not appear.A correlation analysis indicates that an IOSD event observed during the austral summer is highly correlated to the IOD event peaking about 9 months later.One of the possible physical mechanisms underlying this highly significant statistical relationship is proposed.The IOSD and the IOD can occur in sequence with the help of the Mascarene high.The SSTA in the southwestern Indian Ocean persists for several seasons after the mature phase of the IOSD event,likely due to the positive wind–evaporation–SST feedback mechanism.The Mascarene high will be weakened or intensified by this SSTA,which can affect the atmosphere in the tropical region by teleconnection.The pressure gradient between the Mascarene high and the monsoon trough in the tropical Indian Ocean increases（decreases）.Hence,an anticyclone（cyclone） circulation appears over the Arabian Sea-India continent.The easterly or westerly anomalies appear in the equatorial Indian Ocean,inducing the onset stage of the IOD.This study shows that the SSTA associated with the IOSD can lead to the onset of IOD with the aid of atmosphere circulation and also explains why some IOD events in the tropical tend to be followed by IOSD in the southern Indian Ocean.展开更多
Climate models project a positive Indian Ocean Dipole （plOD）-like SST response in the tropical Indian Ocean to global warming, By employing the Community Earth System Model and applying an overriding technique to it...Climate models project a positive Indian Ocean Dipole （plOD）-like SST response in the tropical Indian Ocean to global warming, By employing the Community Earth System Model and applying an overriding technique to its ocean component （version 2 of the Parallel Ocean Program）, this study investigates the similarities and differences of the formation mechanisms for the changes in the tropical Indian Ocean during the plOD versus global warming. Results show that their formation processes and related seasonality are quite similar; in particular, wind-thermocline-SST feedback is the leading mechanism in producing the anomalous cooling over the eastern tropics in both cases. Some differences are also fbund, including the fact that the cooling effect of the vertical advection over the eastern tropical Indian Ocean is dominated by the anomalous vertical velocity during the plOD but by the anomalous upper-ocean stratification under global warming. These findings are lhrther examined through an analysis of the mixed layer heat budget.展开更多
Research on the diffusion characteristics of swells contributes positively to wave energy forecasting, swell monitoring, and early warning. In this work, the South Indian Ocean westerly index(SIWI) and Indian Ocean sw...Research on the diffusion characteristics of swells contributes positively to wave energy forecasting, swell monitoring, and early warning. In this work, the South Indian Ocean westerly index(SIWI) and Indian Ocean swell diffusion effect index(IOSDEI) are defined on the basis of the 45-year(September 1957–August 2002) ERA-40 wave reanalysis data from the European Centre for Medium-Range Weather Forecasts(ECMWF) to analyze the impact of the South Indian Ocean westerlies on the propagation of swell acreage. The following results were obtained: 1) The South Indian Ocean swell mainly propagates from southwest to northeast. The swell also spreads to the Arabian Sea upon reaching low-latitude waters. The 2.0-meter contour of the swell can reach northward to Sri Lankan waters. 2) The size of the IOSDEI is determined by the SIWI strength. The IOSDEI requires approximately 2–3.5 days to fully respond to the SIWI. The correlations between SIWI and IOSDEI show obvious seasonal differences, with the highest correlations found in December–January–February(DJF) and the lowest correlations observed in June–July–August(JJA). 3) The SIWI and IOSDEI have a common period of approximately 1 week in JJA and DJF. The SIWI leads by approximately 2–3 days in this common period.展开更多
The positive phase of the subtropical Indian Ocean dipole(SIOD)is one of the climatic modes in the subtropical southern Indian Ocean that influences the austral summer inter-annual rainfall variability in parts of sou...The positive phase of the subtropical Indian Ocean dipole(SIOD)is one of the climatic modes in the subtropical southern Indian Ocean that influences the austral summer inter-annual rainfall variability in parts of southern Africa.This paper examines austral summer rain-bearing circulation types(CTs)in Africa south of the equator that are related to the positive SIOD and the dynamics through which specific rainfall regions in southern Africa can be influenced by this relationship.Four austral summer rain-bearing CTs were obtained.Among the four CTs,the CT that featured(i)enhanced cyclonic activity in the southwest Indian Ocean;(ii)positive widespread rainfall anomaly in the southwest Indian Ocean;and(iii)low-level convergence of moisture fluxes from the tropical South Atlantic Ocean,tropical Indian Ocean,and the southwest Indian Ocean,over the south-central landmass of Africa,was found to be related to the positive SIOD climatic mode.The relationship also implies that positive SIOD can be expected to increase the amplitude and frequency of occurrence of the aforementioned CT.The linkage between the CT related to the positive SIOD and austral summer homogeneous regions of rainfall anomalies in Africa south of the equator showed that it is the principal CT that is related to the inter-annual rainfall variability of the south-central regions of Africa,where the SIOD is already known to significantly influence its rainfall variability.Hence,through the large-scale patterns of atmospheric circulation associated with the CT,the SIOD can influence the spatial distribution and intensity of rainfall over the preferred landmass through enhanced moisture convergence.展开更多
This study assesses the reproducibility of 31 historical simulations from 1850 to 2014 in the Coupled Model Intercomparison Project phase 6(CMIP6) for the subsurface(Sub-IOD) and surface Indian Ocean Dipole(IOD) and t...This study assesses the reproducibility of 31 historical simulations from 1850 to 2014 in the Coupled Model Intercomparison Project phase 6(CMIP6) for the subsurface(Sub-IOD) and surface Indian Ocean Dipole(IOD) and their association with El Ni?o-Southern Oscillation(ENSO). Most CMIP6 models can reproduce the leading east-west dipole oscillation mode of heat content anomalies in the tropical Indian Ocean(TIO) but largely overestimate the amplitude and the dominant period of the Sub-IOD. Associated with the much steeper west-to-east thermocline tilt of the TIO, the vertical coupling between the Sub-IOD and IOD is overly strong in most CMIP6 models compared to that in the Ocean Reanalysis System 4(ORAS4). Related to this, most models also show a much tighter association of Sub-IOD and IOD events with the canonical ENSO than observations. This explains the more(less) regular Sub-IOD and IOD events in autumn in those models with stronger(weaker) surface-subsurface coupling in TIO. Though all model simulations feature a consistently low bias regarding the percentage of the winter–spring Sub-IOD events co-occurring with a Central Pacific(CP) ENSO, the linkage between a westward-centered CP-ENSO and the Sub-IOD that occurs in winter–spring, independent of the IOD, is well reproduced.展开更多
基金supported by the National Natural Science Foundation of China[grant numbers 41975087,U2242212,and 41975085]supported by the National Natural Science Foundation of China[grant number U2242212]。
文摘Based on reanalysis data from 1979 to 2021,this study explores the spatial distribution of the Southern Indian Ocean Dipole(SIOD)and its individual and synergistic effects with the El Niño-Southern Oscillation(ENSO)on summer precipitation in China.The inverse phase spatial distribution of sea surface temperature anomalies(SSTAs)in the southwest and northeast of the southern Indian Ocean is defined as the SIOD.Positive SIOD events(positive SSTAs in the southwest,negative SSTAs in the northeast)are associated with La Niña events(Central Pacific(CP)type),while negative SIOD events(negative SSTAs in the southwest,positive SSTAs in the northeast)are associated with El Niño events(Eastern Pacific(EP)type).Both SIOD and ENSO have certain impacts on summer precipitation in China.Precipitation in the Yangtze River basin decreases,while precipitation in southern China increases during pure positive SIOD(P_PSIOD)events.During pure negative SIOD(P_NSIOD)events,the changes in precipitation are exactly the opposite of those during P_PSIOD events,which may be due to differences in the cross-equatorial flow in the southern Indian Ocean,particularly in low-level Australian cross-equatorial flow.When positive SIOD and CP-type La Niña events occur simultaneously(PSIOD+La_Niña),precipitation increases in the Yangtze-Huaihe River basin,while it decreases in northern China.When negative SIOD and EP-type El Niño events occur simultaneously(NSIOD+El_Niño),precipitation in the Yangtze-Huaihe River basin is significantly lower than during P_NSIOD events.This is caused by differences in water vapor originating from the Pacific Ocean during different events.
文摘Kidney transplantation(KT)accounts for nearly three-fourths of organ transplants in India,with living donors contributing to 82%of cases.Induction immunosuppression is essential to optimize initial immunosuppression,reduce acute rejections,and enable tailored use of maintenance agents.Rabbit anti-thymocyte globulin(rATG)and interleukin-2 receptor anatagonists(IL-2RA/IL-2RBs)are the most widely used induction therapies.However,data on induction practices across India are limited.To evaluate induction immunosuppression practices across KT centers in India and establish a consensus for different subsets of KT recipients.A nationwide online survey was conducted by the Indian Society of Organ Transplantation(ISOT)among its members(400 KT centers).Responses were analyzed to assess induction practices across diverse donor types,age groups,and immunological risk profiles.Heterogeneity in practices prompted consensus building using a modified Delphi process.Literature review and expert panel discussions(April 2024)were followed by structured voting,and 16 consensus statements were finalized.Of 400 centers approached,254 participated.rATG was the most commonly used induction therapy,followed by IL-2RBs;alemtuzumab was least used.Significant heterogeneity was observed in type,dose,and duration of induction therapy.Consensus recommendations were framed:rATG for high immunological risk recipients and deceased donor KTs;IL-2RB or low-dose rATG for low immunological risk;rituximab in ABOincompatible KTs;and tailoring based on age,diabetes,donor type,infection risk,and affordability.This first ISOT consensus provides 16 India-specific statements on induction therapy in KT.It emphasizes risk-stratified,evidenceinformed,and context-appropriate induction strategies,supporting standardization of care across the country.
基金The Fund of Laoshan Laboratory under contract No.LSKJ202202700the Basic Scientific Fund for National Public Research Institutes of China under contract No.2024Q02+1 种基金the National Natural Science Foundation of China under contract Nos 42076023 and 42430402the Global Change and Air-Sea InteractionⅡProject under contract No.GASI-01-ATP-STwin.
文摘The Indonesian Throughflow(ITF)plays important roles in global ocean circulation and climate systems.Previous studies suggested the ITF interannual variability is driven by both the El Niño-Southern Oscillation(ENSO)and the Indian Ocean Dipole(IOD)events.The detailed processes of ENSO and/or IOD induced anomalies impacting on the ITF,however,are still not clear.In this study,this issue is investigated through causal relation,statistical,and dynamical analyses based on satellite observation.The results show that the driven mechanisms of ENSO on the ITF include two aspects.Firstly,the ENSO related wind field anomalies driven anomalous cyclonic ocean circulation in the western Pacific,and off equatorial upwelling Rossby waves propagating westward to arrive at the western boundary of the Pacific,both tend to induce negative sea surface height anomalies(SSHA)in the western Pacific,favoring ITF reduction since the develop of the El Niño through the following year.Secondly,the ENSO events modulate equatorial Indian Ocean zonal winds through Walker Circulation,which in turn trigger eastward propagating upwelling Kelvin waves and westward propagating downwelling Rossby waves.The Rossby waves are reflected into downwelling Kelvin waves,which then propagate eastward along the equator and the Sumatra-Java coast in the Indian Ocean.As a result,the wave dynamics tend to generate negative(positive)SSHA in the eastern Indian Ocean,and thus enhance(reduce)the ITF transport with time lag of 0-6 months(9-12 months),respectively.Under the IOD condition,the wave dynamics also tend to enhance the ITF in the positive IOD year,and reduce the ITF in the following year.
基金ISRO-RESPOND GAP3332 and PMN-MOES GAP2175 Project support this work.NIO-PMN and MOES-NCPOR supported the deep-sea and Antarctica micrometeorite collections,respectively.
文摘Extraterrestrial phenomena have influenced Earth’s processes throughout geological history.Evaluating the impact of extraterrestrial material on the environment is crucial for understanding the evolution of Earth and life.This study incorporates the investigation of micrometeorites(MMs),abundant cosmic materials on Earth,to understand their influence on the chemical composition and biogeochemistry of the ocean.Comprehensive etching and flux analyses reveal that∼95%of cosmic spherules(CSs)entering seawater are etched or wholly dissolved,supplying nutrients to phytoplankton.Barred spherules show the highest degree of etching(∼19%),followed by porphyritic(∼17%),glass(∼15%),cryptocrystalline(∼12%),scoriaceous(∼10%),G-type(∼9%),and I-type(∼6%).Annually,∼3080 tonnes(t)of olivine from MMs dissolve into seawater,contributing∼495 t of Mg^(2+),∼1110 t of Fe^(2+),and∼1928 t of silicic acid.This signifies that over the Indian Ocean’s∼40 Myr history,∼23 Gt of olivine from CSs has dissolved,providing nutrients to seawater and sequestering∼7 Gt of CO_(2).The world ocean during this time has sequestered∼35 Gt of CO_(2),with fluctuations influenced by extraterrestrial activity.For instance,the Veritas event,lasting∼1.5 Myr,sequestered∼6 Gt of CO_(2)from the atmosphere.A robust flux calculation based on∼2 t of deep-sea sediments from 3610 MMs provides a more accurate estimate of the time-averaged flux of∼229 t yr^(−1).These comprehensive analyses reveal MM’s original characteristics,post-deposition processes,geological record and their overall impact on Earth’s marine environments,thereby contributing to our knowledge of the interconnection between terrestrial and extraterrestrial processes.
基金supported by the National Natural Science Foundation of China[grant numbers 42105030 and 42105066]the Ministry of Commerce,People’s Republic of China.
文摘Tanzania is mainly subject to a bimodal rainfall pattern,characterized by two distinct seasons:the long rains,occurring from March to May,and the short rains,which typically take place from October to December(OND).Short rains are usually less intense but still significantly influence local agriculture.Therefore,with station-based observations and reanalysis data,the current paper examines the interannual variability of OND precipitation in Tanzania from 1993 to 2022 and explores the possible impacts from El Niño–Southern Oscillation(ENSO)and the Indian Ocean Dipole(IOD)as well as the mechanisms.It is found that the Tanzania OND precipitation is above(below)normal in 1997,2006,2011,and 2019(1993,1998,2005,and 2016).The composite difference between wet(dry)years and the climatology indicates that the anomalous lower-level convergence(divergence)and upward(downward)motion are the critical circulation characters for above(below)precipitation.Further analysis indicates ENSO and the IOD are the two main oceanic systems modulating OND precipitation in Tanzania.El Niño and a positive IOD could induce easterly anomalies and weaken the Walker circulation over the Indian Ocean,consequently leading to lower-level convergence in water vapor flux,upward anomalies,and more than normal precipitation in Tanzania.In contrast,La Niña and a negative IOD produce opposite circulation anomalies and less than normal precipitation over Tanzania.Moreover,through partial correlation and Generalized Equilibrium Feedback Analysis,the individual contributions of ENSO and the IOD to circulation are investigated.It is found that although both the IOD and ENSO impact the Walker circulation,the feedback to the IOD is stronger than ENSO.These results provide critical insights into the oceanic drivers and their mechanistic pathways underlying precipitation anomalies in Tanzania.
基金National Natural Science Foundation of China(42288101,42192564)Project of Ministry of Science and Technology of the People’s Republic of China(2020YFA0608802)Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)。
文摘El Niño is frequently followed by La Niña,while La Niña tends to sustain into the next year or even longer,exhibiting a notable phase transition asymmetry(TA)of El Niño-Southern Oscillation(ENSO).This study explores the potential influences of tropical Indian Ocean(TIO)decadal variability on TA based on a comparative analysis of the relationship between the TIO sea surface temperature anomalies(SSTA)and ENSO during different periods.Generally,the TIO SSTA strengthened TA before the 1980s,corresponding to a highly positive relationship between the whole TIO SSTA and ENSO.However,the weakening effect was exhibited after the 1980s when the correlation diminished.After the late 1990s,ENSO was only positively correlated with western TIO,with the westerly exhibit of the SSTA center leading to smaller impacts on TA.Moreover,TIO SSTA tends to weaken TA by promoting the transition efficiency of La Niña,while bringing little effect on that of El Niño.Physically,compared to the mid-1970s,TIO SSTA triggered westerly wind anomalies during the autumn and winter of the La Niña development phase in the central equatorial Pacific in the late 1990s,which sped up the decay of La Niña.It then regenerated westerly anomalies in the following winter,facilitating the development of El Niño.This study quantifies the impact of the TIO SSTA on TA in seasonal signals and investigates the decadal variability of such influence,aiming to further understand phase transition asymmetry and offer valuable insights for the prediction of multi-year La Niña.
文摘In the author list,the corresponding author indicator(*)was inadvertently omitted from HOU Zengqian’s name.This has now been corrected to:“HOU Zengqian¹,*”.The online version of this article was corrected.
文摘In recent years, traditional rice landraces have gained increasing attention among consumers, scientists, and nutritionists because of their nutritional and therapeutic value. The diverse rice gene pool of the Indian subcontinent is bestowed with indigenous rice types augmented with nutrients and phytochemicals. Landraces high in resistant starch and dietary fiber contribute to gut health and help prevent gastrointestinal disorders, whereas those with high-quality protein contents, such as glutelin and lysine, all-trans retinoic acid, as well as iron and zinc contents(even in polished rice), play a vital role in the alleviation of malnutrition and hidden hunger. Metabolomic studies have revealed the presence of novel bioactive molecules, including tocols(e.g., gamma-tocotrienol and alpha-tocopherol), phytosterols(e.g., campestrol, beta-sitosterol, and stigmasterol), phenolic acids(e.g., 2-methoxy-4-vinylphenol, 4-vinylphenol, 3,5-di-tert-butylphenol, 2,4-di-tert-butylphenol, ionol, and 2,6-di-tert-butylphenol), flavonoids [e.g., flavonolignans tricin 4′-O-(threo-β-guaiacylglyceryl) ether and tricin 4′-O-(erythro-β-guaiacylglyceryl) ether], anthocyanins(e.g., delphinidin and cyanidin), carotenoids(e.g., 7,7′,8,8′-tetrahydrolycopene and 1-hydroxylycopene), diterpenoids(e.g., sugiol), vitamin D3(a secosteroid), and bioactive vitamin D(e.g., calcitriol). These bioactive phytochemicals endow Indian rice landraces, rich in antioxidants, with antiphlogistic, antineoplastic, cardiac risk preventive, antiviral, and antitubercular activities, confirming their use in traditional Indian medicine. Furthermore, Indian landraces with a low glycemic index may benefit the Asian Indian phenotype, which is characterized by clinical anomalies such as insulin resistance, dyslipidemia(reduced high-density lipoprotein levels), and high dietary glycemic load. Therefore, the conservation of India's traditional rice varieties is vital for both sustainable agriculture and improving global health.
文摘The current investigation focuses on intertwined relationships of ecology and aquaculture for the benefit of farmers involved in fish farming practices.The study evaluated glucosinolate reduction in black,brown,and white mustard meals as fish feed ingredients for Indian Major Carps.Fish were fed with 10%mustard meal-supplemented diets in three forms:Raw(R),Anti-nutritional Rich(AR),and Anti-nutritional Lowered(AL),alongside a control group using floating feed.The three-month indoor experiment(September-November 2023)was conducted in FRP tanks with triplicate treatments.Blood analysis revealed compromised health in AR-fed carps,with reduced hemoglobin levels in rohu,catla and mrigal and elevated total leukocyte counts indicating inflammation in all the three carps studied here.Liver function was impaired in AR-fed fish,shown by increased alanine transaminase levels,highest in rohu followed by mrigal and catla.Histopathological examination of AR-fed carps liver tissue revealed necrotic spots,deformed hepatocytes,and significant vacuolation.In contrast,AL-fed fish demonstrated improved health parameters through Complete Blood Count analysis,liver function tests,and histo-pathological observations,suggesting successful reduction of anti-nutritional factors in the processed mustard meals.In near future,replacement of unprocessed seed meal with processed seed meal will lead to economic gains in fish farming.
文摘On 14 January 2025,CAFIU Vice-President Ai Ping met with Pradeep Kumar Rawat,Ambassador of India to China.The two sides exchanged views on China-India relations as well as cultural and peopleto-people exchanges.
基金The Science&Technology Innovation Project of Laoshan Laboratory under contract No.LSKJ202201703the China Ocean Mineral Resources R&D Association under contract No.DY135-E2-4-03the Global Change and Air-Sea Interaction II Program under contract No.GASI-04-HYST-01.
文摘The unique features of the Equatorial Undercurrent(EUC)and relations to the Indian Ocean Dipole(IOD)highlight the complexity and importance of the tropical eastern Indian Ocean(EIO),yet the EUC dynamics and associated physical-biogeochemical implications remain patchy.Here,mainly using in situ observations during April-May 2011,we provide direct evidence of the spring eastward EUC and its relations to the southward subsurface salty water and upwelling off Sumatra and reveal its biogeochemical responses.A strong eastward velocity of~1.2 m/s at a depth of 120 m near the equator along the meridional section of 90°E clearly indicates the EUC.The continuum of subsurface salty water from the equator to the offshore region off Sumatra generally shows the pathway and dynamic bridge role of the EUC.The southward shoaling of isotherms and isohalines near the upper boundary of thermocline in the region off Sumatra implies the occurrence of weak upwelling from the subsurface salty water;the early onset of southeasterly wind associated with the positive IOD might be responsible for this phenomenon.The EUC is important in driving the spatial variability of the oxygen minimum zone(OMZ)and subsurface chlorophyll a maximum(SCM)in the tropical EIO.In particular,the EUC may act as a source of O_(2),depressing the upward limit of the OMZ at the equator.Moreover,the eastward depressed EUC induces the downwelling of the OMZ and a deepened and weakened SCM from west to east along the equator.Influenced by EUC transport and upwelling,a southward extension of the OMZ with an uplifted oxycline occurred in the region off Sumatra,and a southward enhanced and shoaled SCM emerged.The results unraveled the dynamic linkages between the EUC and biogeochemical environments,constituting a considerable contribution to the understanding of the physical-biogeochemical-ecological interactions in the tropical EIO.
文摘The present study of metabasalts was carried out to understand the mantle source and geodynamic setting of the Mahakoshal Group in the Central Indian Tectonic Zone.In this study,we present detailed field,petrography,and whole rock geochemistry of the Mahakoshal metabasalts.The Mahakoshal metabasalts are sub-alkaline in nature and belong to the tholeiitic series of rocks.The variation in rareearth element patterns of metabasalts indicates the different degrees of partial melting at shallow as well as deeper depths.Further,Eu/Eu*varies from 0.8 to 1.1(except sample KP-144=0.3),Ce/Ce*varies from 0.97 to 1.05,showing no cerium anomaly,and Nb/Nb*ranges from 0.7 to 1.3(except KP-144=0.1).The magnesium number(Mg#)varies from 0.2 to 0.3,which is quite low,indicating the evolved nature of the metabasalts.The studied metabasalts show E-MORB to OIB-type affinities,which are placed in the trench-distal back-arc setting.The opening of the Mahakoshal Basin is due to retreating orogen in the accretionary orogen setting and is contemporaneous with the assembly of the Columbia Supercontinent(~2.1-1.8 Ga).Hence,field,petrographic,and geochemical signatures indicate that the Mahakoshal basin opened as a back-arc rift basin on the Bundelkhand Craton,and that metabasalts are derived from the mantle that underwent variable degrees of partial melting at different depths.
基金Guangdong Major Project of Basic and Applied Basic Research(2020B0301030004)National Natural Science Foundation of China(U2442202)+1 种基金Key Innovation Team of China Meteorological Administration“Climate Change Detection and Response”(CMA2022ZD03)National Key Research and Development Program of China(2023YFF0805104)。
文摘This study explores the impact of winter sea surface temperature(SST)anomalies in the Southern Indian Ocean on summer precipitation patterns in China,utilizing data from reanalysis sources and Coupled Model Intercomparison Project Phase 6(CMIP6)models.The results reveal that the Southern Indian Ocean Dipole(SIOD),characterized by contrasting SST anomalies in the northeast and southwest regions,acts as a predictor for Chinese summer precipitation patterns,namely floods in the south and drought in the north.In a positive SIOD event,the southwestern Indian Ocean exhibits warmer SSTs,while the northeastern region remains cooler.A negative SIOD event shows the opposite pattern.During the positive phase of the SIOD,the winter SST distribution strengthens the 850-hPa cross-equatorial airflow,generating a robust low-level westerly jet that enhances water vapor transport to the Bay of Bengal(BoB).These air-sea interactions maintain lower SSTs in the northeastern region,which significantly increase the land-sea temperature contrast in the Northern Hemisphere during spring and summer.This strengthened thermal gradient intensifies the southwest monsoon,establishing a strong convergence zone near the South China Sea and amplifying monsoon-driven precipitation in South China.Additionally,CMIP6 models,such as NorESM2-LM and NorCPM1,which accurately simulate the SIOD pattern,effectively capture the seasonal response of cross-equatorial airflow driven by SST anomalies of Southern Indian Ocean.The result highlights the essential role of cross-equatorial airflow generated by the SIOD in forecasting crossseasonal precipitation patterns.
基金Supported by the National Natural Science Foundation of China(41275072,41365007)(Key)Project for Applied Basic Research of Yunnan Province(2011FA031).
文摘Based on the reanalysis data of monthly mean sea surface temperature (SST) from British Hadley Center and ozone mass mixing ratio from National Aeronautics and Space Administration (NASA) during 1980-2015, two indexes IOBI and IODI of the main modes characterizing SST changes in the tropical Indian Ocean——Indian Ocean Basin (IOB) and Indian Ocean Dipole (IOD) were calculated firstly, and then the correlation of SST anomaly (SSTA) in the tropical Indian Ocean and ozone mass mixing ratio in the stratosphere over East Asia from 1980 to 2015 was analyzed. Besides, the impact of SST changes in the tropical Indian Ocean on the distribution of ozone layer in East Asia was discussed. The results show that SST changes in the tropical Indian Ocean had significant effects on stratospheric ozone distribution in East Asia, and it was consistent with the temporal changes of IOB and IOD. IOBI and IODI had a certain correlation with stratospheric ozone changes in East Asia, with a particularly significant correlation in the lower stratosphere (70 hPa) and middle stratosphere (40 hPa) especially during spring and autumn.
基金supported by the National Natural Science Foundation of China, (No. 40976015)National Basic Research Program of China under Grant No. (2010CB950302)
文摘The relationship between ENSO and Indian Ocean Dipole was discussed by using the data set of sea temperature from Scripps Institute of Oceanography, the air temperature at 1000hPa from the NCEP reanalysis data and the Nino3 index from the Climate Prediction Center （CPC） of U.S.A. during the period from 1955 to 2001. The results show that there exists a Dipole on the maximum temperature anomalous level （MTAL） in the Indian Ocean, which close relates to ENSO in the Pacific Ocean. During El Nino periods there are good relationships between ENSO and Indian Ocean Dipole which maximum correlation occurring when ENSO leads by one month, but in La Nina periods the relationship is not so good. The distribution of Dipole in Indian Ocean is from northeast to southwest, which one （west） pole in 65°E - 75°E, 6°S - 10°S and the other in 85°E - 95°E, 2°N - 6°N, which is different from that defined by Saij. The correlation coefficients of Nino3 index with temperature anomalies in the west/east poles on the MTAL are over 0.4 - 0.15, respectively. It is a main sea temperature system in the tropical Indian Ocean. However, in the surface layer from sea surface to the depth of 20 m - 30 m there is no such a dipole with opposite sea temperature anomalies in the NE and SW of tropical Indian Ocean. The SSTA in the NE might be influenced by the sensible exchange process because the evolution of sea and 1 000 hPa air temperature anomaly time series of the NE of tropical Indian Ocean is quite similar except those during 1962 - 1963 and 1986. The periods of Indian Ocean Dipole are shorter than that of ENSO, and about 1 to 6-year.
基金The National Natural Science Foundation of China under contract Nos 41106016 and 41330963the National Basic Research Program(973 Program)of China under contract No.2012CB417403
文摘The variation in the Indian Ocean is investigated using Hadley center sea surface temperature（SST） data during the period 1958–2010.All the first empirical orthogonal function（EOF） modes of the SST anomalies（SSTA） in different domains represent the basin-wide warming and are closely related to the Pacific El Ni o– Southern Oscillation（ENSO） phenomenon.Further examination suggests that the impact of ENSO on the tropical Indian Ocean is stronger than that on the southern Indian Ocean.The second EOF modes in different domains show different features.It shows a clear east-west SSTA dipole pattern in the tropical Indian Ocean（Indian Ocean dipole,IOD）,and a southwest-northeast SSTA dipole in the southern Indian Ocean（Indian Ocean subtropical dipole,IOSD）.It is further revealed that the IOSD is also the main structure of the second EOF mode on the whole basin-scale,in which the IOD pattern does not appear.A correlation analysis indicates that an IOSD event observed during the austral summer is highly correlated to the IOD event peaking about 9 months later.One of the possible physical mechanisms underlying this highly significant statistical relationship is proposed.The IOSD and the IOD can occur in sequence with the help of the Mascarene high.The SSTA in the southwestern Indian Ocean persists for several seasons after the mature phase of the IOSD event,likely due to the positive wind–evaporation–SST feedback mechanism.The Mascarene high will be weakened or intensified by this SSTA,which can affect the atmosphere in the tropical region by teleconnection.The pressure gradient between the Mascarene high and the monsoon trough in the tropical Indian Ocean increases（decreases）.Hence,an anticyclone（cyclone） circulation appears over the Arabian Sea-India continent.The easterly or westerly anomalies appear in the equatorial Indian Ocean,inducing the onset stage of the IOD.This study shows that the SSTA associated with the IOSD can lead to the onset of IOD with the aid of atmosphere circulation and also explains why some IOD events in the tropical tend to be followed by IOSD in the southern Indian Ocean.
基金supported by the National Basic Research Program of China (Grant No. 2012CB955600)the "Strategic Priority Research Program" of the Chinese Academy of Sciences (Grant No. XDA11010302)+3 种基金the National Natural Science Foundation of China (Grant No. 41376009)the Joint Program of Shandong Province and National Natural Science Foundation of China (Grant No. U1406401)the National Science Foundation (Grant No. AGS-1249173)supported by the Office of Science of the U.S. Department of Energy as part of the Regional and Global Climate Modeling program
文摘Climate models project a positive Indian Ocean Dipole （plOD）-like SST response in the tropical Indian Ocean to global warming, By employing the Community Earth System Model and applying an overriding technique to its ocean component （version 2 of the Parallel Ocean Program）, this study investigates the similarities and differences of the formation mechanisms for the changes in the tropical Indian Ocean during the plOD versus global warming. Results show that their formation processes and related seasonality are quite similar; in particular, wind-thermocline-SST feedback is the leading mechanism in producing the anomalous cooling over the eastern tropics in both cases. Some differences are also fbund, including the fact that the cooling effect of the vertical advection over the eastern tropical Indian Ocean is dominated by the anomalous vertical velocity during the plOD but by the anomalous upper-ocean stratification under global warming. These findings are lhrther examined through an analysis of the mixed layer heat budget.
基金supported by the National Key R&D Program (No.2017YFC1405103)the Joint Funds of the National Natural Science Foundation of China (No.U170 6220)+1 种基金the National Natural Science Foundation of China (Nos.41901006, 41471005, and 41271016)the Natural Science Foundation of Shandong Province (No.ZR 2019BD005)。
文摘Research on the diffusion characteristics of swells contributes positively to wave energy forecasting, swell monitoring, and early warning. In this work, the South Indian Ocean westerly index(SIWI) and Indian Ocean swell diffusion effect index(IOSDEI) are defined on the basis of the 45-year(September 1957–August 2002) ERA-40 wave reanalysis data from the European Centre for Medium-Range Weather Forecasts(ECMWF) to analyze the impact of the South Indian Ocean westerlies on the propagation of swell acreage. The following results were obtained: 1) The South Indian Ocean swell mainly propagates from southwest to northeast. The swell also spreads to the Arabian Sea upon reaching low-latitude waters. The 2.0-meter contour of the swell can reach northward to Sri Lankan waters. 2) The size of the IOSDEI is determined by the SIWI strength. The IOSDEI requires approximately 2–3.5 days to fully respond to the SIWI. The correlations between SIWI and IOSDEI show obvious seasonal differences, with the highest correlations found in December–January–February(DJF) and the lowest correlations observed in June–July–August(JJA). 3) The SIWI and IOSDEI have a common period of approximately 1 week in JJA and DJF. The SIWI leads by approximately 2–3 days in this common period.
文摘The positive phase of the subtropical Indian Ocean dipole(SIOD)is one of the climatic modes in the subtropical southern Indian Ocean that influences the austral summer inter-annual rainfall variability in parts of southern Africa.This paper examines austral summer rain-bearing circulation types(CTs)in Africa south of the equator that are related to the positive SIOD and the dynamics through which specific rainfall regions in southern Africa can be influenced by this relationship.Four austral summer rain-bearing CTs were obtained.Among the four CTs,the CT that featured(i)enhanced cyclonic activity in the southwest Indian Ocean;(ii)positive widespread rainfall anomaly in the southwest Indian Ocean;and(iii)low-level convergence of moisture fluxes from the tropical South Atlantic Ocean,tropical Indian Ocean,and the southwest Indian Ocean,over the south-central landmass of Africa,was found to be related to the positive SIOD climatic mode.The relationship also implies that positive SIOD can be expected to increase the amplitude and frequency of occurrence of the aforementioned CT.The linkage between the CT related to the positive SIOD and austral summer homogeneous regions of rainfall anomalies in Africa south of the equator showed that it is the principal CT that is related to the inter-annual rainfall variability of the south-central regions of Africa,where the SIOD is already known to significantly influence its rainfall variability.Hence,through the large-scale patterns of atmospheric circulation associated with the CT,the SIOD can influence the spatial distribution and intensity of rainfall over the preferred landmass through enhanced moisture convergence.
基金supported by the National Key R&D Program of China (Grant No. 2019YFA0606701)the Guangdong Major Project of Basic and Applied Basic Research (Grant No. 2020B0301030004)。
文摘This study assesses the reproducibility of 31 historical simulations from 1850 to 2014 in the Coupled Model Intercomparison Project phase 6(CMIP6) for the subsurface(Sub-IOD) and surface Indian Ocean Dipole(IOD) and their association with El Ni?o-Southern Oscillation(ENSO). Most CMIP6 models can reproduce the leading east-west dipole oscillation mode of heat content anomalies in the tropical Indian Ocean(TIO) but largely overestimate the amplitude and the dominant period of the Sub-IOD. Associated with the much steeper west-to-east thermocline tilt of the TIO, the vertical coupling between the Sub-IOD and IOD is overly strong in most CMIP6 models compared to that in the Ocean Reanalysis System 4(ORAS4). Related to this, most models also show a much tighter association of Sub-IOD and IOD events with the canonical ENSO than observations. This explains the more(less) regular Sub-IOD and IOD events in autumn in those models with stronger(weaker) surface-subsurface coupling in TIO. Though all model simulations feature a consistently low bias regarding the percentage of the winter–spring Sub-IOD events co-occurring with a Central Pacific(CP) ENSO, the linkage between a westward-centered CP-ENSO and the Sub-IOD that occurs in winter–spring, independent of the IOD, is well reproduced.
