Atlantic salmon Salmo salar were reared at four stocking densities--high density D1 （final density -39 kg/m^3）, medium densities DE （-29 kg/m^3） and D3 （~19 kg/m^3）, and low density D4 （-12 kg/m^3）- for 40 day...Atlantic salmon Salmo salar were reared at four stocking densities--high density D1 （final density -39 kg/m^3）, medium densities DE （-29 kg/m^3） and D3 （~19 kg/m^3）, and low density D4 （-12 kg/m^3）- for 40 days to investigate the effect of stocking density on their growth performance, body composition and energy budgets. Stocking density did not significantly affect specific growth rate in terms of weight （SGRw） but did affect specific growth rate in terms of energy （SGRe）. Stocking density significantly influenced the ration level （RLw and RLe）, feed conversion ratio （FCRw and FCRe） and apparent digestibility rate （ADR）. Ration level and FCRw tended to increase with increasing density. Fish at the highest density D~ and lowest density D4 showed lower FCRe and higher ADR than at medium densities. Stocking density significantly affected protein and energy contents of the body but did not affect its moisture, lipid, or ash contents. The expenditure of energy for metabolism in the low-density and high-density groups was lower than that in the medium-density groups. Stocking density affected energy utilization from the feces but had no effect on excretion rate. The greater energy allocation to growth at high density and low density may be attributed to reduced metabolic rate and increased apparent digestibility rate. These findings provide information that will assist selection of suitable stocking densities in the Atlantic-salmon-farming industry.展开更多
The present study sampled the intestinal content of healthy and unhealthy Atlantic salmon(Salmo salar L.),the ambient water of unhealthy fish,and the biofilter material in the recirculating aquaculture system(RAS)to u...The present study sampled the intestinal content of healthy and unhealthy Atlantic salmon(Salmo salar L.),the ambient water of unhealthy fish,and the biofilter material in the recirculating aquaculture system(RAS)to understand differences in the intestinal microbiota.The V4--V5 regions of the prokaryotic 16S rRNA genes in the samples were analyzed by MiSeq high-throughput sequencing.The fish were adults with no differences in body length or weight.Representative members of the intestinal microbiota were identified.The intestinal microbiota of the healthy fish included Proteobacteria(44.33%),Actinobacteria(17.89%),Baeteroidetes(15.25%),and Firmicutes(9.11%),among which the families Mierococcaceae and Oxalobacteraceae and genera Sphingomonas,Streptomyces,Pedobacter,Janthinobacterium,Burkholderia,and Balneimonas were most abundant.Proteobacteria(70.46%),Bacteroidetes(7.59%),and Firmicutes(7.55%)dominated the microbiota of unhealthy fish,and Chloroflexi(2.71%),and Aliivibrio and Vibrio as well as genera in the family Aeromonadaceae were most strongly represented.Overall,the intestinal hindgut microbiota differed between healthy and unhealthy fish.This study offers a useful tool for monitoring the health status of fish and for screening the utility of probiotics by studying the intestinal microbiota.展开更多
Atlantic salmon reared in recirculating aquaculture system(RAS) may lead to inappropriately high stocking density, because ?sh live in a limited space. Finding the suitable stocking density of Atlantic salmon reared i...Atlantic salmon reared in recirculating aquaculture system(RAS) may lead to inappropriately high stocking density, because ?sh live in a limited space. Finding the suitable stocking density of Atlantic salmon reared in RAS is very important for RAS industry. In this paper, the in?uence of stocking density on growth and some stress related physiological factors were investigated to evaluate the ef fects of stocking density. The ?sh were reared for 220 days at ?ve densities(A: 24 kg/m^3; B: 21 kg/m^3; C: 15 kg/m^3; D: 9 kg/m^3 and E: 6 kg/m^3). The results show that 30 kg/m^3 might be the maximum density which RAS can af ford in China. The stocking densities under 30 kg/m^3 have no ef fect on mortality of Atlantic salmon reared in RAS. However, the speci?c growth rate(SGR), ?nal weight and weight gain in the high density group were signi?cantly lower than the lower density groups and middle density groups. Moreover, feed conversion rate(FCR) had a negative correlation with density. Plasma hormone T_3 and GH showed signi?cant decrease with the increase of the stocking density of the experiment. Furthermore, thyroid hormone(T 3), GH(growth hormone) activities were decreased with stocking density increase. However, plasma cortisol, GOT(glutamic oxalacetic transaminase) and GPT(glutamic pyruvic transaminase) activities were increase with stocking density increase. And the stocking density has no ef fects on plasma lysozyme of Atlantic salmon reared in RAS. These investigations would also help devise effcient ways to rear adult Atlantic salmon in China and may, in a way, help spread salmon mariculture in China.展开更多
The effects of different feeds and feeding regimes on growth performance, flesh quality and fecal viscosity of Atlantic salmon （Salmo salar L.） in recirculating aquaculture systems （R.AS） were investigated. Fish ...The effects of different feeds and feeding regimes on growth performance, flesh quality and fecal viscosity of Atlantic salmon （Salmo salar L.） in recirculating aquaculture systems （R.AS） were investigated. Fish （initial body weight of 1677 g＋ 157 g） were fed with four commercial feeds （Nosan salmon-NS, Aller gold-AG, Skretting salmon-SS and Hart ye-HY） in two feeding regimes （80% and 100% satiation） for 78 d. The results showed that salmon specific growth ratio （SGR） and weight gain ratio （WGR） were significantly affected by feed type and feeding regime （P〈0.05）. Feed conversion ratio （FCR） varied between 0.93 and 3.40, which was significantly affected by feed type （P〈0.05）, and slightly improved with increased satiation degree. The activities of digestive enzymes including protease, lipase and amylase were also significantly affected by feed type and feeding regime （P〈0.05）, increasing with satiation degree. Flesh qualities for vitamin E, hydroxyproline （HYP）, liquid loss and muscle pH among all groups showed significant differences （P〈0.05）, ranging from 26.67 to 29.67, while no obvious difference was found in flesh color. Fecal viscosity for different treatments showed no significant difference, though improvement was found in 100% satiation group. From present experiment, it was concluded that both feed type and feeding regime can affect the important quality attributes of Atlantic salmon.展开更多
The Brazilian coast is characterized by different tidal regimes and distinct meteorological influences. The northern part has larger tidal amplitudes and is permanently affected by trade winds and tropical disturbance...The Brazilian coast is characterized by different tidal regimes and distinct meteorological influences. The northern part has larger tidal amplitudes and is permanently affected by trade winds and tropical disturbances; the southern portion has smaller tidal amplitudes and is frequently influenced by extratropical cyclone activity. Besides these aspects, many features regarding current structure and behavior are also present, such as the equatorial system of currents, the subtropical gyre and the corresponding western boundary currents, and the Brazil-Malvinas confluence region. Within this context, efforts were made to develop the BRAZCOAST system, capable of describing the processes that determine the oceanic circulation from large to coastal scales. A customized version of the Princeton Ocean Model(POM) was implemented in a basin-scale domain covering the whole of the tropical and southern Atlantic Ocean, with 0.5° spatial resolution, as well as three nested grids with(1/12)° resolution covering the different parts of the Brazilian shelf, in a one-way procedure. POM was modified to include tidal potential generator terms and a partially-clamped boundary condition for tidal elevations. The coarse grid captured large-scale features, while the nested grids detailed local circulations affected by bathymetry and coastal restrictions. An interesting aspect at the coarse grid level was the relevance of the Weddell Sea to the location of the tidal amphidromic systems.展开更多
As one of very rare and unusual tracks of hurricane Ophelia, it exists over the North Atlantic Ocean during the period of 9-17 October 2017. The present work investigates the role played by blocking system over North ...As one of very rare and unusual tracks of hurricane Ophelia, it exists over the North Atlantic Ocean during the period of 9-17 October 2017. The present work investigates the role played by blocking system over North America on the development of hurricane Ophelia. The 6-hour daily data of NCEP/NCAR reanalysis composites for the meteorological parameters are used. The meteorological elements used in the present work are (geopotential height and meridional wind components at 500-hpa level). The domain of this data is the northern hemisphere domain. Moreover, the 6-hour data on the surface pressure at the center of hurricane Ophelia and its maximum wind through the period (9-17 October) have been used. The time series, anomaly and correlation coefficient methods have been used to analyze the meteorological data. The results revealed that the persistence of blocking high system over the North America during the period of 9-17 October 2017 controls the development, strength, and the track of hurricane Ophelia over the North Atlantic Ocean.展开更多
This paper analyzes the performance and operation of ecologically-based production systems in the Atlantic Forest in southern Brazil in an integrated approach to their multifunctional characteristics and rural develop...This paper analyzes the performance and operation of ecologically-based production systems in the Atlantic Forest in southern Brazil in an integrated approach to their multifunctional characteristics and rural development. Nowadays the Atlantic Forest is considered the most threatenet biome, because of exploitation of their biological resources and unsuitable agricultural purposes. Banana cultivation is one of biggest commercial productions in atlantic south portion of forest, showing two different cropping systems： one using conventional management tehniques and other antagonistic, ecological based. The ecological system is compatible with the conservation of sustainable use of forests. The article presents a comparative analysis-diagnosis of major production and cultivation systems of banana, using the production systems approach, with evaluation of economic and technical indicators. The database is composed by 17 interviews conducted under field conditions in 2007. As a result, the technical and economic functioning of ecological systems demonstrate achieve economic efficiency, in general, higher than conventional systems. Furthermore, some key characteristics of ecological based systems focus on food production and income generation for farmers without harming areas of the Atlantic Forest, being in equilibrium with tropical dynamic and being an important instrument for the restoration of degraded ecosystems and for local development.展开更多
Tropical waters show different regional aspects due to specificities in their nutrient biogeochemical cycles, which can affect the carbon system and influence their regional role as sinks or sources of CO<sub>2&...Tropical waters show different regional aspects due to specificities in their nutrient biogeochemical cycles, which can affect the carbon system and influence their regional role as sinks or sources of CO<sub>2</sub>. This study was performed on particular tropical areas that present a different seasonal behaviour related to the carbon cycle observed in the late rainy season (July 2013). Understanding the CO<sub>2</sub> drawdown and outgassing potential in these areas is needed to call attention to more long-term monitoring efforts and protect understudied tropical coastal systems more efficiently. This study is focused on nutrient values, hydrological data, biogeochemical carbon behaviour linked to the carbonate system and includes estimates of CO<sub>2</sub> fluxes in three contrasting areas off the northeastern Brazilian shelf: 1) an urbanised estuary (Recife-REC), 2) a coastal Island (Itamaracá-ITA) and 3) an oceanic archipelago (Fernando de Noronha-FN). In general, REC acted as a source, while ITA and FN as carbon sinks. In ITA, despite the high DIC and Total Alkalinity observed (mean ~2360 μmol·kg<sup>-1</sup>), the sink is associated with an effective cascading of atmospheric CO<sub>2</sub> associated with turbulent shallow waters coupled with biogenic removal of and precipitation of CaCO<sub>3</sub> by coralline algae. FN acted as a sink, linked to minor decreases in Total Alkalinity (mean~2295 μmol·kg<sup>-1</sup>) influenced by ammonium-based primary production, nitrogen fixation and sporadic entrainment of nutrient rich waters in the upper thermocline. More studies in different western tropical Atlantic coastal systems can improve the knowledge of tropical shelf seas and their contribution to the ocean carbon budget under specific regional trophic regimes.展开更多
Atlantic salmon(Salmo salar)represents the primary species in aquaculture.The gut microbiota plays a crucial role in nutrient processing and protection against pathogenic bacteria.Nonetheless,the composition and funct...Atlantic salmon(Salmo salar)represents the primary species in aquaculture.The gut microbiota plays a crucial role in nutrient processing and protection against pathogenic bacteria.Nonetheless,the composition and functionality of the gut microbiota in Salmo salar at different growth stages remain largely unexplored.This study investigated the alterations within the gut microbial communities and their associated metabolites across different growth stages of Salmo salar,specifically when the body weights were 1.0 kg(S1 group),2.0 kg(S2 group),4.0 kg(S3 group),and 6.0 kg(S4 group),using microbiome sequencing and liquid chromatographymass spectrometry(LC-MS)technology.Results indicated significant changes in the gut microbiota and metabolite profiles concurrent with fish growth.Notably,the abundance of Firmicutes decreased,and Proteobacteria increased,resulting in a decreased Firmicutes/Bacteroidetes(F/B)ratio.Concurrently,the abundance of potential pathogenic bacteria such as Stenotrophomonas,Vibrio,Aeromonas,Staphylococcaceae,Enterobacteriaceae,Enterococcaceae,and Haemophilus increased,whereas beneficial bacteria like Lactobacillus and Bacilli decreased.The gut microbiota in the S1 group exhibited an increase in the abundance of beneficial bacteria.Conversely,in the S2,S3,and S4 groups,the prevalence of pathogenic bacteria increased.Metabolic profiling revealed significant upregulation of arachidonic acid(ARA)and taurine in the S2 and S3 groups,while citric acid,riboflavin,and pantothenic acid notably increased in the S4 group.Particularly,several amino acids such as threonine,lysine,and serine in the gut microbiota metabolites were significantly reduced in the S2,S3,and S4 groups,correlating positively with the respective essential amino acid concentrations in muscle tissue.The S1 group exhibited a more active gut microbiota associated with amino acid metabolism,resulting in higher muscle amino acid content.This study identified gut microbiota and its metabolic products at different growth stages of Salmo salar,providing a scientific basis for proactive intervention of gut microbiota and improve the quality of aquatic products.展开更多
Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and noctu...Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and nocturnal surveys using the Line Transect method in seven forest fragments varying from 7.32 ha to 469.76 ha, within a 4000 ha forest island archipelago, in Pernambuco State, Atlantic forest of northeastern Brazil. We calculated species density, population size, biomass and synergetic biomass, and recorded direct and indirect human impacts along the study transects. We recorded 44 mammalian species, of which 45.5% (n = 20) went extinct through hunting. The smallest forest fragment had the lowest richness, diversity, population size, and total biomass. It also had no synergetic biomass. The largest fragment had the highest richness, total density, and population size. There was a statistically significant relationship between fragment area and number of gunshots heard and suspended hunting platforms found;between population size and gunshots heard, suspended hunting platforms, free-roaming and feral dogs, and between total density and free-roaming and feral dogs. After more than 500 years of colonization hunting is still devastating, with larger fragments being linked to more hunters. Higher mammal abundances attracted more free-roaming and feral dogs, which have adapted to hunt wildlife on their own. Unless we protect every single forest fragment and create sustainable landscapes, we will not be able to save this hotspot’s hotspot.展开更多
On December 12,2020,I cast off with Argo,my trusty boat,for a solo voyage across the Atlantic.As we departed San Sebastian at dawn,the exhaustion from preparation already had me longing for sleep,which was a strange d...On December 12,2020,I cast off with Argo,my trusty boat,for a solo voyage across the Atlantic.As we departed San Sebastian at dawn,the exhaustion from preparation already had me longing for sleep,which was a strange desire on the very first day of what was to be a 70⁃day expedition.展开更多
The Pacific Meridional Mode(PMM)and the Atlantic Meridional Mode(AMM)are key modes of interannual sea surface temperature(SST)variability in the Pacific and Atlantic Oceans,respectively.Analysis of CMIP6 model outputs...The Pacific Meridional Mode(PMM)and the Atlantic Meridional Mode(AMM)are key modes of interannual sea surface temperature(SST)variability in the Pacific and Atlantic Oceans,respectively.Analysis of CMIP6 model outputs reveals a robust intensification of the PMM under global warming,whereas the AMM exhibits no consensus among models.These different responses are attributed to mid-to-high latitude atmospheric forcing and subtropical feedback mechanisms.Changes in the upper-level westerly jet drive distinct atmospheric variability over the North Pacific and Atlantic,amplifying sea-level pressure variations associated with the PMM but weakening those linked to the AMM.The SST response to atmospheric forcing shows an increase in the Pacific and a decrease in the Atlantic,both of which are significantly positively correlated with the respective changes in each mode.The enhanced wind-evaporation-SST(WES)feedback,primarily driven by rising background SSTs,positively impacts the intensification of both modes.In the subtropical Pacific,the PMM is further strengthened by an increasing latent heat flux response.The enhancement of the PMM is principally connected to intensified atmospheric forcing and strengthened subtropical feedback.Although the WES feedback is enhanced to some extent,wind anomalies that oppose the climatological state reduce latent heat flux.Combined with the weakening of atmospheric forcing over the Atlantic,this phenomenon contributes to the uncertainty in the AMM's response to global warming.展开更多
Southwest China(SWC)is one of the major grain-producing areas in China,and the surface air temperature(SAT)during autumn has a substantial influence on grain production and planting.It is therefore important to unders...Southwest China(SWC)is one of the major grain-producing areas in China,and the surface air temperature(SAT)during autumn has a substantial influence on grain production and planting.It is therefore important to understand temporal changes in the SAT over SWC(SWC-SAT).Our analysis of observational and reanalysis datasets shows that the autumn SWC-SAT exhibits significant multidecadal variability.A significantly strong positive correlation also exists between the autumn SWC-SAT and the Atlantic multidecadal oscillation(AMO)time series(correlation coefficient of 0.85).These results suggest that the AMO is a remote driver of multidecadal variability in the autumn SWC-SAT.Further analyses show that the North Atlantic sea surface temperature anomalies(SSTA)associated with the AMO modulate the multidecadal variability of the autumn SWC-SAT through triggering the Africa-Asia multidecadal teleconnection(AAMT)pattern.Specifically,the AAMT corresponds to geopotential height anomalies over SWC,which adjust the local thickness of the air column and thereby induce multidecadal variability of the autumn SWC-SAT.This potential mechanism,derived from observational and reanalysis datasets,was verified by using a linear barotropic model and the Community Atmosphere Model version 4.Our results from combining observations and numerical modeling simulations indicate that the North Atlantic SSTA may act as a key pacemaker for the multidecadal SAT variability over SWC.展开更多
The Equatorial Atlantic Ocean,a region crucial to understanding Earth’s tectonic processes and advancing the theory of plate tectonics,remains the focus of extensive research aimed at unraveling its evolution.However...The Equatorial Atlantic Ocean,a region crucial to understanding Earth’s tectonic processes and advancing the theory of plate tectonics,remains the focus of extensive research aimed at unraveling its evolution.However,its complex structural setting and contentious formation timeline have posed significant challenges.Through a comprehensive review of contemporary scientific litera-ture,we have identified three distinct phases for its evolution:pre-breakup,syn-breakup,and post-breakup,providing more detailed in-sights into the tectonic evolution of the Equatorial Atlantic.Prior to 110 Myr,the African and South American Plates underwent stretching predominantly from North to South,with the emergence of the Parana plume.This condition has led to the formation of nu-merous fracture zones and a triple junction.During the syn-breakup phase,spanning from 110 Myr to 90 Myr,the central region of the Equatorial Atlantic fully opened up,establishing a connection between the northern and southern waterways.However,the develop-ment of multiple ridge segments separated by numerous fracture zones in the central Equatorial Atlantic exhibited considerable com-plexity.The underlying causes for these complex structural formations remain elusive.Following the Chicxulub meteorite impact around 66 Myr and the emergence of the Sierra Leone hotspot,a pair of oceanic plateau‘twins’and a series of seamount chains were formed as a result of mantle plume tails.Consequently,the timeline of the Equatorial Atlantic’s tectonic evolution has gradually be-come clearer.However,due to the extensive timescale and the multitude of events involved in its formation,disputes about the precise-timing of various events still remain.The evolution of the Equatorial Atlantic has witnessed numerous ridge propagations,hotspot formations,and meteorite impacts,highlighting the need for further investigation into their interactions.The absence of identified magnetic isochrons in the Equatorial region emphasizes the urgency of additional exploration and analysis of its geological and geo-physical data.展开更多
Compound extreme climate events involving multiple meteorological elements usually have a more severe impact on the environment and human health than single-element extreme events.However,the current definition of mul...Compound extreme climate events involving multiple meteorological elements usually have a more severe impact on the environment and human health than single-element extreme events.However,the current definition of multi-element compound extreme events is proposed from meteorological and statistical perspectives,without integrating health data,making the conclusions less practical for guiding health risk prevention.This study identified the threshold for hot–dry compound extreme events with high mortality risks(HMHDs)in China,using daily mortality data and temperature–humidity data from 278 districts or counties,and explored the interdecadal change and driving mechanisms of HMHD frequency in China from 1979 to 2021.The results show a significant increase in annual HMHD frequency in China after 2000,mainly occurring in summer(June,July,August).The northwestern to western regions of China(Xinjiang,Inner Mongolia,Gansu),and from the southwestern to the areas south of the Yangtze River(Sichuan,Hubei,Hunan,Jiangxi,Fujian,Guizhou,Yunnan),experience an increase of>10 days.The authors find that the interdecadal abrupt change in HMHD frequency can be attributed to the shift of the Atlantic Multidecadal Oscillation from a negative to a positive phase by affecting the Silk Road teleconnection.展开更多
Since the publication of The Black Atlantic:Modernity and Double Consciousness(1993),the concept of the“Black Atlantic”has become a key paradigm in diaspora studies and cultural criticism.The“Black Atlantic”challe...Since the publication of The Black Atlantic:Modernity and Double Consciousness(1993),the concept of the“Black Atlantic”has become a key paradigm in diaspora studies and cultural criticism.The“Black Atlantic”challenges the historical dominance of Western-centered Atlantic history by situating slavery,forced migration,and diasporic intellectual production as central components of modernity itself.This essay re-examines the meaning of the“Black Atlantic”by situating it against Eurocentric Atlantic history,exploring its philosophical dialogue with modernity,interrogating its relationship with Marxism,and reassessing its significance in the context of globalization.In doing so,it seeks to clarify both the transformative power and the limitations of Gilroy’s paradigm while also suggesting directions for future scholarship that reconnect the“Black Atlantic”to Africa,Marxism,and anti-capitalist critique.展开更多
This study investigated the fluctuations in the relationship between the Silk Road Pattern(SRP)and the boreal summer North Atlantic Oscillation(SNAO).The results indicated that the SRP–SNAO relationship was relativel...This study investigated the fluctuations in the relationship between the Silk Road Pattern(SRP)and the boreal summer North Atlantic Oscillation(SNAO).The results indicated that the SRP–SNAO relationship was relatively weak during 1958–2022,which was primarily due to fluctuations,particularly the reversal in their relationship since the late 1990s.Using wavelet coherence analysis,the authors identified a strong SRP–SNAO linkage on a 4–8-yr timescale,in particular during the mid-1970s to the early/mid-1990s.This strong linkage is mainly attributable to the intensification and eastward movement of the southern part of the SNAO around the mid/late 1970s,which favored the strong connection between the SNAO and the SRP.Additionally,the interdecadal changes of the atmospheric circulations over the North Atlantic and Eurasia around the mid/late 1970s that resembled the circulation anomalies related to the strong SRP–SNAO linkage,may also have provided a favorable background for the strong connection between the two teleconnections.These findings on the fluctuations in the SRP–SNAO linkage may offer important implications for understanding the impact of the SNAO on the SRP and the variability of the SRP.展开更多
A strong （weak） East Asian summer monsoon （EASM） is usually concurrent with the tripole pattern of North Atlantic SST anomalies on the interannual timescale during summer, which has positive （negative） SST anoma...A strong （weak） East Asian summer monsoon （EASM） is usually concurrent with the tripole pattern of North Atlantic SST anomalies on the interannual timescale during summer, which has positive （negative） SST anomalies in the northwestern North Atlantic and negative （positive） SST anomalies in the subpolar and tropical ocean. The mechanisms responsible for this linkage are diagnosed in the present study. It is shown that a barotropie wave-train pattern occurring over the Atlantic-Eurasia region likely acts as a link between the EASM and the SST tripole during summer. This wave-train pattern is concurrent with geopotential height anomalies over the Ural Mountains, which has a substantial effect on the EASM. Diagnosis based on observations and linear dynamical model results reveals that the mechanism for maintaining the wave-train pattern involves both the anomalous diabatic heating and synoptic eddy-vorticity forcing. Since the North Atlantic SST tripole is closely coupled with the North Atlantic Oscillation （NAO）, the relationships between these two factors and the EASM are also examined. It is found that the connection of the EASM with the summer SST tripole is sensitive to the meridional location of the tripole, which is characterized by large seasonal variations due to the north-south movement of the activity centers of the NAO. The SST tripole that has a strong relationship with the EASM appears to be closely coupled with the NAO in the previous spring rather than in the simultaneous summer.展开更多
The Atlantic Multidecadal Oscillation （AMO）, the multidecadal variation of North Atlantic sea surface temperature （SST）, exhibits an oscillation with a period of 65-80 years and an amplitude of 0.4℃. Observationa...The Atlantic Multidecadal Oscillation （AMO）, the multidecadal variation of North Atlantic sea surface temperature （SST）, exhibits an oscillation with a period of 65-80 years and an amplitude of 0.4℃. Observational composite analyses reveal that the warm phase AMO is linked to warmer winters in East China, with enhanced precipitation in the north of this region and reduced precipitation in the south, on multidecadal time scales. The pattern is reversed during the cold phase AMO. Whether the AMO acts as a forcing of the multidecadal winter climate of East China is explored by investigating the atmospheric response to warm AMO SST anomalies in a large ensemble of atmospheric general circulation model （AGCM） experiments. The results from three AGCMs are consistent and suggest that the AMO warmth favors warmer winters in East China. This influence is realized through inducing negative surface air pressure anomalies in the hemispheric-wide domain extending from the midlatitude North Atlantic to midlatitude Eurasia. These negative surface anomalies favor the weakening of the Mongolian Cold High, and thus induce a weaker East Asian Winter Monsoon.展开更多
基金Supported by the National Natural Science Foundation of China(No.31240012)the Earmarked Fund for Modern Agro-industry Technology Research System+2 种基金the Special Foundation for Postdoctoral Innovative Projects of Shandong Province(No.201101009)the National Key Technology R&D Program of China(No.2011BAD13B04)The Key Laboratory of Mariculture(KLM),Ministry of Education,Ocean University of China(OUC)
文摘Atlantic salmon Salmo salar were reared at four stocking densities--high density D1 （final density -39 kg/m^3）, medium densities DE （-29 kg/m^3） and D3 （~19 kg/m^3）, and low density D4 （-12 kg/m^3）- for 40 days to investigate the effect of stocking density on their growth performance, body composition and energy budgets. Stocking density did not significantly affect specific growth rate in terms of weight （SGRw） but did affect specific growth rate in terms of energy （SGRe）. Stocking density significantly influenced the ration level （RLw and RLe）, feed conversion ratio （FCRw and FCRe） and apparent digestibility rate （ADR）. Ration level and FCRw tended to increase with increasing density. Fish at the highest density D~ and lowest density D4 showed lower FCRe and higher ADR than at medium densities. Stocking density significantly affected protein and energy contents of the body but did not affect its moisture, lipid, or ash contents. The expenditure of energy for metabolism in the low-density and high-density groups was lower than that in the medium-density groups. Stocking density affected energy utilization from the feces but had no effect on excretion rate. The greater energy allocation to growth at high density and low density may be attributed to reduced metabolic rate and increased apparent digestibility rate. These findings provide information that will assist selection of suitable stocking densities in the Atlantic-salmon-farming industry.
基金Supported by the National Natural Science Foundation of China(Nos.31472312,41306152,31402283)the Qingdao Innovation Talents Program(No.13-CX-16)+2 种基金the National Key Technology Research and Development Program of China(No.2014BAD08B09)the Earmarked Fund for Modern Agroindustry Technology Research System(No.CARS-48)the Project for International S&T Cooperation Program of China(No.2014DFA31030)
文摘The present study sampled the intestinal content of healthy and unhealthy Atlantic salmon(Salmo salar L.),the ambient water of unhealthy fish,and the biofilter material in the recirculating aquaculture system(RAS)to understand differences in the intestinal microbiota.The V4--V5 regions of the prokaryotic 16S rRNA genes in the samples were analyzed by MiSeq high-throughput sequencing.The fish were adults with no differences in body length or weight.Representative members of the intestinal microbiota were identified.The intestinal microbiota of the healthy fish included Proteobacteria(44.33%),Actinobacteria(17.89%),Baeteroidetes(15.25%),and Firmicutes(9.11%),among which the families Mierococcaceae and Oxalobacteraceae and genera Sphingomonas,Streptomyces,Pedobacter,Janthinobacterium,Burkholderia,and Balneimonas were most abundant.Proteobacteria(70.46%),Bacteroidetes(7.59%),and Firmicutes(7.55%)dominated the microbiota of unhealthy fish,and Chloroflexi(2.71%),and Aliivibrio and Vibrio as well as genera in the family Aeromonadaceae were most strongly represented.Overall,the intestinal hindgut microbiota differed between healthy and unhealthy fish.This study offers a useful tool for monitoring the health status of fish and for screening the utility of probiotics by studying the intestinal microbiota.
基金Supported by the National Science Foundation for Young Scientists of China(No.31402314,31402283)the Agency of Science and Technology of Shandong Province(No.2013GHY11514)+4 种基金the Modern Agro-Industry Technology Research System(No.nycytx-50)the Scientific and Technology Innovation Project Financially Supported by Qingdao National Laboratory for Marine Science and Technology(Nos.2015ASKJ02,2015ASKJ02-03-03)the Youth Innovation Promotion Association CAS,the Chinese Academy of Science and Technology Service Network Planning(No.KFJ-EW-STS-060)the China Agriculture Research System(No.CARS-47)the Shandong Provincial Key S&T Innovation Project(No.2017CXGC0101)
文摘Atlantic salmon reared in recirculating aquaculture system(RAS) may lead to inappropriately high stocking density, because ?sh live in a limited space. Finding the suitable stocking density of Atlantic salmon reared in RAS is very important for RAS industry. In this paper, the in?uence of stocking density on growth and some stress related physiological factors were investigated to evaluate the ef fects of stocking density. The ?sh were reared for 220 days at ?ve densities(A: 24 kg/m^3; B: 21 kg/m^3; C: 15 kg/m^3; D: 9 kg/m^3 and E: 6 kg/m^3). The results show that 30 kg/m^3 might be the maximum density which RAS can af ford in China. The stocking densities under 30 kg/m^3 have no ef fect on mortality of Atlantic salmon reared in RAS. However, the speci?c growth rate(SGR), ?nal weight and weight gain in the high density group were signi?cantly lower than the lower density groups and middle density groups. Moreover, feed conversion rate(FCR) had a negative correlation with density. Plasma hormone T_3 and GH showed signi?cant decrease with the increase of the stocking density of the experiment. Furthermore, thyroid hormone(T 3), GH(growth hormone) activities were decreased with stocking density increase. However, plasma cortisol, GOT(glutamic oxalacetic transaminase) and GPT(glutamic pyruvic transaminase) activities were increase with stocking density increase. And the stocking density has no ef fects on plasma lysozyme of Atlantic salmon reared in RAS. These investigations would also help devise effcient ways to rear adult Atlantic salmon in China and may, in a way, help spread salmon mariculture in China.
基金supported by the National Key Technologies R&D Program(2011BAD13B04)the earmarked fund for Modern Agro-industry Technology Research System(CARS-48)the National Natural Science Foundation of China(No.31240012)
文摘The effects of different feeds and feeding regimes on growth performance, flesh quality and fecal viscosity of Atlantic salmon （Salmo salar L.） in recirculating aquaculture systems （R.AS） were investigated. Fish （initial body weight of 1677 g＋ 157 g） were fed with four commercial feeds （Nosan salmon-NS, Aller gold-AG, Skretting salmon-SS and Hart ye-HY） in two feeding regimes （80% and 100% satiation） for 78 d. The results showed that salmon specific growth ratio （SGR） and weight gain ratio （WGR） were significantly affected by feed type and feeding regime （P〈0.05）. Feed conversion ratio （FCR） varied between 0.93 and 3.40, which was significantly affected by feed type （P〈0.05）, and slightly improved with increased satiation degree. The activities of digestive enzymes including protease, lipase and amylase were also significantly affected by feed type and feeding regime （P〈0.05）, increasing with satiation degree. Flesh qualities for vitamin E, hydroxyproline （HYP）, liquid loss and muscle pH among all groups showed significant differences （P〈0.05）, ranging from 26.67 to 29.67, while no obvious difference was found in flesh color. Fecal viscosity for different treatments showed no significant difference, though improvement was found in 100% satiation group. From present experiment, it was concluded that both feed type and feeding regime can affect the important quality attributes of Atlantic salmon.
基金the Brazilian agencies FAPESP (Sao Paulo State Research Agency) and CNPq (National Council for Scientific and Technological Development) for funding throughout the development of this work
文摘The Brazilian coast is characterized by different tidal regimes and distinct meteorological influences. The northern part has larger tidal amplitudes and is permanently affected by trade winds and tropical disturbances; the southern portion has smaller tidal amplitudes and is frequently influenced by extratropical cyclone activity. Besides these aspects, many features regarding current structure and behavior are also present, such as the equatorial system of currents, the subtropical gyre and the corresponding western boundary currents, and the Brazil-Malvinas confluence region. Within this context, efforts were made to develop the BRAZCOAST system, capable of describing the processes that determine the oceanic circulation from large to coastal scales. A customized version of the Princeton Ocean Model(POM) was implemented in a basin-scale domain covering the whole of the tropical and southern Atlantic Ocean, with 0.5° spatial resolution, as well as three nested grids with(1/12)° resolution covering the different parts of the Brazilian shelf, in a one-way procedure. POM was modified to include tidal potential generator terms and a partially-clamped boundary condition for tidal elevations. The coarse grid captured large-scale features, while the nested grids detailed local circulations affected by bathymetry and coastal restrictions. An interesting aspect at the coarse grid level was the relevance of the Weddell Sea to the location of the tidal amphidromic systems.
文摘As one of very rare and unusual tracks of hurricane Ophelia, it exists over the North Atlantic Ocean during the period of 9-17 October 2017. The present work investigates the role played by blocking system over North America on the development of hurricane Ophelia. The 6-hour daily data of NCEP/NCAR reanalysis composites for the meteorological parameters are used. The meteorological elements used in the present work are (geopotential height and meridional wind components at 500-hpa level). The domain of this data is the northern hemisphere domain. Moreover, the 6-hour data on the surface pressure at the center of hurricane Ophelia and its maximum wind through the period (9-17 October) have been used. The time series, anomaly and correlation coefficient methods have been used to analyze the meteorological data. The results revealed that the persistence of blocking high system over the North America during the period of 9-17 October 2017 controls the development, strength, and the track of hurricane Ophelia over the North Atlantic Ocean.
文摘This paper analyzes the performance and operation of ecologically-based production systems in the Atlantic Forest in southern Brazil in an integrated approach to their multifunctional characteristics and rural development. Nowadays the Atlantic Forest is considered the most threatenet biome, because of exploitation of their biological resources and unsuitable agricultural purposes. Banana cultivation is one of biggest commercial productions in atlantic south portion of forest, showing two different cropping systems： one using conventional management tehniques and other antagonistic, ecological based. The ecological system is compatible with the conservation of sustainable use of forests. The article presents a comparative analysis-diagnosis of major production and cultivation systems of banana, using the production systems approach, with evaluation of economic and technical indicators. The database is composed by 17 interviews conducted under field conditions in 2007. As a result, the technical and economic functioning of ecological systems demonstrate achieve economic efficiency, in general, higher than conventional systems. Furthermore, some key characteristics of ecological based systems focus on food production and income generation for farmers without harming areas of the Atlantic Forest, being in equilibrium with tropical dynamic and being an important instrument for the restoration of degraded ecosystems and for local development.
文摘Tropical waters show different regional aspects due to specificities in their nutrient biogeochemical cycles, which can affect the carbon system and influence their regional role as sinks or sources of CO<sub>2</sub>. This study was performed on particular tropical areas that present a different seasonal behaviour related to the carbon cycle observed in the late rainy season (July 2013). Understanding the CO<sub>2</sub> drawdown and outgassing potential in these areas is needed to call attention to more long-term monitoring efforts and protect understudied tropical coastal systems more efficiently. This study is focused on nutrient values, hydrological data, biogeochemical carbon behaviour linked to the carbonate system and includes estimates of CO<sub>2</sub> fluxes in three contrasting areas off the northeastern Brazilian shelf: 1) an urbanised estuary (Recife-REC), 2) a coastal Island (Itamaracá-ITA) and 3) an oceanic archipelago (Fernando de Noronha-FN). In general, REC acted as a source, while ITA and FN as carbon sinks. In ITA, despite the high DIC and Total Alkalinity observed (mean ~2360 μmol·kg<sup>-1</sup>), the sink is associated with an effective cascading of atmospheric CO<sub>2</sub> associated with turbulent shallow waters coupled with biogenic removal of and precipitation of CaCO<sub>3</sub> by coralline algae. FN acted as a sink, linked to minor decreases in Total Alkalinity (mean~2295 μmol·kg<sup>-1</sup>) influenced by ammonium-based primary production, nitrogen fixation and sporadic entrainment of nutrient rich waters in the upper thermocline. More studies in different western tropical Atlantic coastal systems can improve the knowledge of tropical shelf seas and their contribution to the ocean carbon budget under specific regional trophic regimes.
基金supported by the Key R&D Program of Shandong Province(No.2021LZGC027)the Shandong Provincial Natural Science Foundation(No.ZR202102250235)+1 种基金the Major Agricultural Application Technology Innovation Projects in Shandong Province(No.SD2019YY 006)the‘First Class Fishery Discipline’Program in Shandong Province,China。
文摘Atlantic salmon(Salmo salar)represents the primary species in aquaculture.The gut microbiota plays a crucial role in nutrient processing and protection against pathogenic bacteria.Nonetheless,the composition and functionality of the gut microbiota in Salmo salar at different growth stages remain largely unexplored.This study investigated the alterations within the gut microbial communities and their associated metabolites across different growth stages of Salmo salar,specifically when the body weights were 1.0 kg(S1 group),2.0 kg(S2 group),4.0 kg(S3 group),and 6.0 kg(S4 group),using microbiome sequencing and liquid chromatographymass spectrometry(LC-MS)technology.Results indicated significant changes in the gut microbiota and metabolite profiles concurrent with fish growth.Notably,the abundance of Firmicutes decreased,and Proteobacteria increased,resulting in a decreased Firmicutes/Bacteroidetes(F/B)ratio.Concurrently,the abundance of potential pathogenic bacteria such as Stenotrophomonas,Vibrio,Aeromonas,Staphylococcaceae,Enterobacteriaceae,Enterococcaceae,and Haemophilus increased,whereas beneficial bacteria like Lactobacillus and Bacilli decreased.The gut microbiota in the S1 group exhibited an increase in the abundance of beneficial bacteria.Conversely,in the S2,S3,and S4 groups,the prevalence of pathogenic bacteria increased.Metabolic profiling revealed significant upregulation of arachidonic acid(ARA)and taurine in the S2 and S3 groups,while citric acid,riboflavin,and pantothenic acid notably increased in the S4 group.Particularly,several amino acids such as threonine,lysine,and serine in the gut microbiota metabolites were significantly reduced in the S2,S3,and S4 groups,correlating positively with the respective essential amino acid concentrations in muscle tissue.The S1 group exhibited a more active gut microbiota associated with amino acid metabolism,resulting in higher muscle amino acid content.This study identified gut microbiota and its metabolic products at different growth stages of Salmo salar,providing a scientific basis for proactive intervention of gut microbiota and improve the quality of aquatic products.
文摘Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and nocturnal surveys using the Line Transect method in seven forest fragments varying from 7.32 ha to 469.76 ha, within a 4000 ha forest island archipelago, in Pernambuco State, Atlantic forest of northeastern Brazil. We calculated species density, population size, biomass and synergetic biomass, and recorded direct and indirect human impacts along the study transects. We recorded 44 mammalian species, of which 45.5% (n = 20) went extinct through hunting. The smallest forest fragment had the lowest richness, diversity, population size, and total biomass. It also had no synergetic biomass. The largest fragment had the highest richness, total density, and population size. There was a statistically significant relationship between fragment area and number of gunshots heard and suspended hunting platforms found;between population size and gunshots heard, suspended hunting platforms, free-roaming and feral dogs, and between total density and free-roaming and feral dogs. After more than 500 years of colonization hunting is still devastating, with larger fragments being linked to more hunters. Higher mammal abundances attracted more free-roaming and feral dogs, which have adapted to hunt wildlife on their own. Unless we protect every single forest fragment and create sustainable landscapes, we will not be able to save this hotspot’s hotspot.
文摘On December 12,2020,I cast off with Argo,my trusty boat,for a solo voyage across the Atlantic.As we departed San Sebastian at dawn,the exhaustion from preparation already had me longing for sleep,which was a strange desire on the very first day of what was to be a 70⁃day expedition.
基金the National Natural Science Foundation of China(Nos.42230405,41975092)the National Key R&D Program of China(No.2023YFF0805100)+1 种基金the Shandong Natural Science Foundation Project(No.ZR2019ZD12)the Taishan Scholars Project of Shandong Province(No.tsqn202306095)。
文摘The Pacific Meridional Mode(PMM)and the Atlantic Meridional Mode(AMM)are key modes of interannual sea surface temperature(SST)variability in the Pacific and Atlantic Oceans,respectively.Analysis of CMIP6 model outputs reveals a robust intensification of the PMM under global warming,whereas the AMM exhibits no consensus among models.These different responses are attributed to mid-to-high latitude atmospheric forcing and subtropical feedback mechanisms.Changes in the upper-level westerly jet drive distinct atmospheric variability over the North Pacific and Atlantic,amplifying sea-level pressure variations associated with the PMM but weakening those linked to the AMM.The SST response to atmospheric forcing shows an increase in the Pacific and a decrease in the Atlantic,both of which are significantly positively correlated with the respective changes in each mode.The enhanced wind-evaporation-SST(WES)feedback,primarily driven by rising background SSTs,positively impacts the intensification of both modes.In the subtropical Pacific,the PMM is further strengthened by an increasing latent heat flux response.The enhancement of the PMM is principally connected to intensified atmospheric forcing and strengthened subtropical feedback.Although the WES feedback is enhanced to some extent,wind anomalies that oppose the climatological state reduce latent heat flux.Combined with the weakening of atmospheric forcing over the Atlantic,this phenomenon contributes to the uncertainty in the AMM's response to global warming.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2442210,42175042,and 42275059)the Natural Science Foundation of Sichuan Province(Grant No.2024NSFTD0017)+1 种基金the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(Grant No.2019QZKK0103)the Natural Science Foundation of Chongqing(Grant No.cstc2021jcyj-msxmX0698).
文摘Southwest China(SWC)is one of the major grain-producing areas in China,and the surface air temperature(SAT)during autumn has a substantial influence on grain production and planting.It is therefore important to understand temporal changes in the SAT over SWC(SWC-SAT).Our analysis of observational and reanalysis datasets shows that the autumn SWC-SAT exhibits significant multidecadal variability.A significantly strong positive correlation also exists between the autumn SWC-SAT and the Atlantic multidecadal oscillation(AMO)time series(correlation coefficient of 0.85).These results suggest that the AMO is a remote driver of multidecadal variability in the autumn SWC-SAT.Further analyses show that the North Atlantic sea surface temperature anomalies(SSTA)associated with the AMO modulate the multidecadal variability of the autumn SWC-SAT through triggering the Africa-Asia multidecadal teleconnection(AAMT)pattern.Specifically,the AAMT corresponds to geopotential height anomalies over SWC,which adjust the local thickness of the air column and thereby induce multidecadal variability of the autumn SWC-SAT.This potential mechanism,derived from observational and reanalysis datasets,was verified by using a linear barotropic model and the Community Atmosphere Model version 4.Our results from combining observations and numerical modeling simulations indicate that the North Atlantic SSTA may act as a key pacemaker for the multidecadal SAT variability over SWC.
基金supported by the National Natural Science Foundation of China(Nos.42376071,42006056)the Special Fund of South China Sea Institute of Oceanol-ogy of the Chinese Academy of Sciences(No.SCSIO 2024QY02)the Chinese Academy of Sciences Pro-ject(No.Y4SL021).
文摘The Equatorial Atlantic Ocean,a region crucial to understanding Earth’s tectonic processes and advancing the theory of plate tectonics,remains the focus of extensive research aimed at unraveling its evolution.However,its complex structural setting and contentious formation timeline have posed significant challenges.Through a comprehensive review of contemporary scientific litera-ture,we have identified three distinct phases for its evolution:pre-breakup,syn-breakup,and post-breakup,providing more detailed in-sights into the tectonic evolution of the Equatorial Atlantic.Prior to 110 Myr,the African and South American Plates underwent stretching predominantly from North to South,with the emergence of the Parana plume.This condition has led to the formation of nu-merous fracture zones and a triple junction.During the syn-breakup phase,spanning from 110 Myr to 90 Myr,the central region of the Equatorial Atlantic fully opened up,establishing a connection between the northern and southern waterways.However,the develop-ment of multiple ridge segments separated by numerous fracture zones in the central Equatorial Atlantic exhibited considerable com-plexity.The underlying causes for these complex structural formations remain elusive.Following the Chicxulub meteorite impact around 66 Myr and the emergence of the Sierra Leone hotspot,a pair of oceanic plateau‘twins’and a series of seamount chains were formed as a result of mantle plume tails.Consequently,the timeline of the Equatorial Atlantic’s tectonic evolution has gradually be-come clearer.However,due to the extensive timescale and the multitude of events involved in its formation,disputes about the precise-timing of various events still remain.The evolution of the Equatorial Atlantic has witnessed numerous ridge propagations,hotspot formations,and meteorite impacts,highlighting the need for further investigation into their interactions.The absence of identified magnetic isochrons in the Equatorial region emphasizes the urgency of additional exploration and analysis of its geological and geo-physical data.
基金funded by the National Natural Science Foundation of China[grant number U2442202]the National Key Research and Development Program of China[grant number 2018YFA0606200]+1 种基金the Guangdong Major Project of Basic and Applied Basic Research[grant number 2020B0301030004]the Science and Technology Project of the Tibet Autonomous Region[grant number XZ202402ZD0006-06]。
文摘Compound extreme climate events involving multiple meteorological elements usually have a more severe impact on the environment and human health than single-element extreme events.However,the current definition of multi-element compound extreme events is proposed from meteorological and statistical perspectives,without integrating health data,making the conclusions less practical for guiding health risk prevention.This study identified the threshold for hot–dry compound extreme events with high mortality risks(HMHDs)in China,using daily mortality data and temperature–humidity data from 278 districts or counties,and explored the interdecadal change and driving mechanisms of HMHD frequency in China from 1979 to 2021.The results show a significant increase in annual HMHD frequency in China after 2000,mainly occurring in summer(June,July,August).The northwestern to western regions of China(Xinjiang,Inner Mongolia,Gansu),and from the southwestern to the areas south of the Yangtze River(Sichuan,Hubei,Hunan,Jiangxi,Fujian,Guizhou,Yunnan),experience an increase of>10 days.The authors find that the interdecadal abrupt change in HMHD frequency can be attributed to the shift of the Atlantic Multidecadal Oscillation from a negative to a positive phase by affecting the Silk Road teleconnection.
文摘Since the publication of The Black Atlantic:Modernity and Double Consciousness(1993),the concept of the“Black Atlantic”has become a key paradigm in diaspora studies and cultural criticism.The“Black Atlantic”challenges the historical dominance of Western-centered Atlantic history by situating slavery,forced migration,and diasporic intellectual production as central components of modernity itself.This essay re-examines the meaning of the“Black Atlantic”by situating it against Eurocentric Atlantic history,exploring its philosophical dialogue with modernity,interrogating its relationship with Marxism,and reassessing its significance in the context of globalization.In doing so,it seeks to clarify both the transformative power and the limitations of Gilroy’s paradigm while also suggesting directions for future scholarship that reconnect the“Black Atlantic”to Africa,Marxism,and anti-capitalist critique.
基金jointly supported by the National Natural Science Foundation of China[grant numbers 41605058 and 41831175]the Joint Open Project of the Key Laboratory of Meteorological Disaster,the Ministry of Education,the Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,NUIST[grant number KLME202104]。
文摘This study investigated the fluctuations in the relationship between the Silk Road Pattern(SRP)and the boreal summer North Atlantic Oscillation(SNAO).The results indicated that the SRP–SNAO relationship was relatively weak during 1958–2022,which was primarily due to fluctuations,particularly the reversal in their relationship since the late 1990s.Using wavelet coherence analysis,the authors identified a strong SRP–SNAO linkage on a 4–8-yr timescale,in particular during the mid-1970s to the early/mid-1990s.This strong linkage is mainly attributable to the intensification and eastward movement of the southern part of the SNAO around the mid/late 1970s,which favored the strong connection between the SNAO and the SRP.Additionally,the interdecadal changes of the atmospheric circulations over the North Atlantic and Eurasia around the mid/late 1970s that resembled the circulation anomalies related to the strong SRP–SNAO linkage,may also have provided a favorable background for the strong connection between the two teleconnections.These findings on the fluctuations in the SRP–SNAO linkage may offer important implications for understanding the impact of the SNAO on the SRP and the variability of the SRP.
基金jointly supported by the National Basic Research Program of China (Grant Nos. 2010CB950404, 2013CB430203, 2010CB950501 and 2012CB955901)the National Natural Science Foundation of China (Grant No. 41205058)+1 种基金the China Postdoctoral Science Foundation (Grant No. 2012M510634)the National Science and Technology Support Program of China (Grant No. 2009BAC51B05)
文摘A strong （weak） East Asian summer monsoon （EASM） is usually concurrent with the tripole pattern of North Atlantic SST anomalies on the interannual timescale during summer, which has positive （negative） SST anomalies in the northwestern North Atlantic and negative （positive） SST anomalies in the subpolar and tropical ocean. The mechanisms responsible for this linkage are diagnosed in the present study. It is shown that a barotropie wave-train pattern occurring over the Atlantic-Eurasia region likely acts as a link between the EASM and the SST tripole during summer. This wave-train pattern is concurrent with geopotential height anomalies over the Ural Mountains, which has a substantial effect on the EASM. Diagnosis based on observations and linear dynamical model results reveals that the mechanism for maintaining the wave-train pattern involves both the anomalous diabatic heating and synoptic eddy-vorticity forcing. Since the North Atlantic SST tripole is closely coupled with the North Atlantic Oscillation （NAO）, the relationships between these two factors and the EASM are also examined. It is found that the connection of the EASM with the summer SST tripole is sensitive to the meridional location of the tripole, which is characterized by large seasonal variations due to the north-south movement of the activity centers of the NAO. The SST tripole that has a strong relationship with the EASM appears to be closely coupled with the NAO in the previous spring rather than in the simultaneous summer.
文摘The Atlantic Multidecadal Oscillation （AMO）, the multidecadal variation of North Atlantic sea surface temperature （SST）, exhibits an oscillation with a period of 65-80 years and an amplitude of 0.4℃. Observational composite analyses reveal that the warm phase AMO is linked to warmer winters in East China, with enhanced precipitation in the north of this region and reduced precipitation in the south, on multidecadal time scales. The pattern is reversed during the cold phase AMO. Whether the AMO acts as a forcing of the multidecadal winter climate of East China is explored by investigating the atmospheric response to warm AMO SST anomalies in a large ensemble of atmospheric general circulation model （AGCM） experiments. The results from three AGCMs are consistent and suggest that the AMO warmth favors warmer winters in East China. This influence is realized through inducing negative surface air pressure anomalies in the hemispheric-wide domain extending from the midlatitude North Atlantic to midlatitude Eurasia. These negative surface anomalies favor the weakening of the Mongolian Cold High, and thus induce a weaker East Asian Winter Monsoon.
