the background of transitions in microblade industries in hokkaido northern japan abstract the purpose of this paper is to discuss the archaeological transitions among microblade industries in hokkaido and to propose some possible relations between human activities and natural environment hokkaido is situated in the north of the japanese archipelago and the microblade industries in this region lasted approximately from 24 000 to 13 000 cal bp corresponding to the climatic changes of the mis2 last glacial maximum lgm cold2 and mis2 late glacial warm lg warm the primary purpose of this paper is to describe the whole picture of transitions observed in microblade industries through a series of examinations on the size of microblades maintenance of burins and the stone tool classes results suggest that the following changes in hunting related stone tools were occurred during the lg warm 1 miniaturization in the part of spears microblades 2 high frequency in burin maintenance and 3 appearance of the new hunting weapon i e projectile points and axes then a preliminary discussion on the possible relations between human activities and the natural environment including some significant climate changes is made referring to the recent studies on the analyses of charred deposits on pottery from the taisho 3 site which belongs to lg warm given the fact that the alterations in the environment and human activities were coincident i propose the hypothesis that the transitions in microblade industries in hokkaido was an outcome of human adaptation to the fluctuation in accessible natural resources caused by the globally occurred warming trend

systematic occurrences of malformed teratological acritarchs in the run up of early palaeozoic δ13c isotope excursions abstract the late ordovician and silurian are characterised by several strong global positive 13 c carb excursions some of them exceed 5 and thus belong to the strongest perturbations of the carbon cycle in the phanerozoic the onset of the excursions is characterised by extinction and or turnover events of several groups of marine invertebrates the causal mechanisms of the carbon cycle perturbations however are still unknown and currently a matter of vigorous scientific debate our own investigations in the hirnantian latest ordovician have shown that the onset of the major 13 c excursion hice is characterised by very high abundances of acritarchs showing abnormal teratological forms a critical review of published reports of abnormal acritarchs from the late ordovician to early devonian and a correlation of their occurrences with the global stable carbon isotope curve show that high abundances of teratological forms of acritarchs are often coeval to the run up of 13 c excursions high abundances of teratological forms in modern marine protists are commonly observed in environments with a high degree of environmental stress in the fossil record the challenge is to attribute abnormal forms of organisms to specific environmental circumstances our study implies that they are somehow related to the global carbon cycle i e to carbon isotopic composition of the ambient sea water and that they share a common extrinsic cause with the contemporaneous extinction and or turnover events in other fossil groups

the 3d oceanic mixed layer response to hurricane gilbert upper ocean heat and mass budgets are examined from three snapshots of data acquired during and after the passage of hurricane gilbert in the western gulf of mexico measurements prior to storm passage indicated a warm core eddy in the region with velocities of o 1 m s21 based upon conservation of heat and mass the threedimensional mixed layer processes are quantified from the data during and subsequent to hurricane passage horizontal advection due to geostrophic velocities is significant in the eddy regime suggesting that prestorm oceanic variability is important when background flows have the same magnitude as the mixed layer current response storm induced near inertial currents lead to large vertical advection magnitudes as they diverge from and converge toward the storm track surface fluxes estimated by reducing flight level winds to 10 m indicate a maximum wind stress of 4 2 n m22 and a heat flux of 1200 w m 22 in the directly forced region the upward heat flux after the passage of the storm has a maximum of 200 w m22 corresponding to a less than 7 m s21 wind speed entrainment mixing across the mixed layer base is estimated using three bulk entrainment closure schemes that differ in their physical basis of parameterization entrainment remains the dominant mechanism in controlling the heat and mass budgets irrespective of the scheme depending on the magnitudes of friction velocity surface fluxes and or shear across the mixed layer base the pattern and location of maximum entrainment rates differ in the directly forced region while the general area of maximum entrainment is in the right rear quadrant of the storm shear induced entrainment scheme predicts a narrow region of cooling compared to the the stressinduced mixing scheme and observed sst decreases after the storm passage the maximum contribution to the mixed layer dynamics is associated with shear induced entrainment mixing forced by near inertial motions up to the third day as indicated by bulk richardson numbers that remained below criticality thus entrainment based on a combination of surface fluxes friction velocity and shear across the entrainment zone may be more relevant for three dimensional ocean response studies

enhanced wind driven downwelling flow in warm oceanic eddy features during the intensification of tropical cyclone isaac 2012 observations and theory abstracttropical cyclones tcs typically produce intense oceanic upwelling underneath the storm s center and weaker and broader downwelling outside upwelled regions however several cases of predominantly downwelling responses over warm anticyclonic mesoscale oceanic features were recently reported where the ensuing upper ocean warming prevented significant cooling of the sea surface and tcs rapidly attained and maintained major status elucidating downwelling responses is critical to better understanding tc intensification over warm mesoscale oceanic features airborne ocean profilers deployed over the gulf of mexico s eddy features during the intensification of tropical storm isaac into a hurricane measured isothermal downwelling of up to 60 m over a 12 h interval 5 m h 1 or twice the upwelling strength underneath the storm s center this displacement occurred over a warm core eddy that extended underneath isaac s left side where the ensuing upper ocean warming was 8 kw m 2 sea surface tempera

cambrian ordovician acritarchs in the meguma terrane nova scotia canada resolution of early paleozoic stratigraphy and implications for paleogeography organic walled microfossils acritarchs provide age constraints for the previously poorly dated cambrian and lower ordovician turbiditic goldenville and halifax groups in the northern appalachian meguma terrane of nova scotia and address controversies about stratigraphy and provenance the oldest exposed formation of the 8 km thick goldenville group contains the trace fossil oldhamia which suggests an age of late early cambrian whereas the coticule bearing uppermost formation yielded an acritarch species consistent with middle cambrian epoch 3 age the conformably overlying 5 km thick halifax group includes basal pyritiferous units that yielded a late cambrian furongian assemblage of acritarch species providing further confirmation that the underlying manganese bearing formations are of cambrian epoch 3 age and not ordovician as recently claimed overlying nonpyritiferous formations contain the early ordovician graptolite rhabdinopora flabelliformis flabelliformis and acritarchs of similar age samples collected up section from the graptolite occurrence yielded acritarch species that are indicative of the later tremadocian and floian the new fossil data confirm a gap in age of 30 m y between the halifax group and the overlying silurian to lower devonian rockville notch group the new ages are consistent with stratigraphic units defined in regional mapping and support recent interpretation of fundamental differences in depositional and tectonic environments between the northwestern and southeastern parts of the meguma terrane they also provide new constraints on paleogeography of the terrane by confirming age similarities to stratigraphy in north wales with which correlation has been proposed previously based mainly on lithological similarities

biodiversity patterns of ordovician marine microphytoplankton from baltica comparison with other fossil groups and sea level changes abstract based on the extensive literature on ordovician acritarchs biodiversity curves of marine microphytoplankton of the palaeocontinent baltica have been compiled the dataset is derived from more than 100 publications and includes over 600 species whose ranges can be used in diversity analysis stratigraphically well constrained data from the rapla and mannamaa boreholes northern estonia are analysed separately in order to provide additional information on the middle to late ordovician microphytoplankton evolution on shallow shelf settings the total species diversity and normalised diversity curves based on range through data show a slight decrease from the tremadocian to floian which may partly be attributed to limited data available a continuous increase in diversity from the base of the dapingian to late darriwilian early katian can be observed with highest total diversity approaching 250 species in the keila regional stage the highest appearance rates are recorded in the dapingian and darriwilian diversity progressively diminished after the early katian with a more pronounced decrease in the upper ordovician porkuni regional stage corresponding to the hirnantian a significant faunal turnover took place in the uppermost ordovician pirgu and porkuni stages with high extinction rates as well as the appearance of many acritarch taxa that are typical of the silurian floras the phytoplankton diversity curves match rather well with those of several other fossil groups in baltica notably brachiopods and ostracods comparison with other palynomorphs reveals both similarities and differences the chitinozoans show the highest diversities in the upper darriwilian but their later decline predates that of acritarchs a rapid diversification of scolecodonts jawed polychaetes can also be observed in the upper darriwilian however unlike acritarchs or chitinozoans their diversity continues to increase until the uppermost katian the acritarch diversity changes are analysed and discussed in the context of palaeogeographic northwards drifting of baltica and palaeoclimatologic changes rising sea levels up to the middle part of the upper ordovician the increasing diversity of the phytoplankton not only roughly correlates with the baltic and global sea level changes but also with the diversification of marine invertebrate groups

human responses to climate change on obsidian source exploitation during the upper paleolithic in the central highlands central japan abstract upper paleolithic hunter gatherers intensively exploited obsidian sources 1200 2000 m a s l in the central highlands central japan previous studies have suggested that the last glacial maximum lgm decreased human obsidian procurement in the source area because of its high altitude however the relationship between the impacts of the lgm and human responses in the source area based on convincing evidence from the paleoclimate obsidian provenance data and archaeology remains poorly understood this study examines the correlations among pollen record datasets during the past 30 000 years from the central highlands 1400 m a s l more than 85 000 pieces of obsidian provenance data for the chubu kanto region and chronological sequences of upper paleolithic industries in the central highlands through synthetic analysis we reconstruct historical changes in the human environment interaction in the central highlands during the upper paleolithic our combined data shows the early lgm constraining the procurement activity at the sources an increase in active human responses to the lgm cold phase and changes in the land use of the source area in the terminal lgm triggered by the appearance of new lithic technology and the reorganization of mobility ranges we find that human adaptations to the lgm conditions related to the natural resource exploitation around a latitude of 36 n were complex

chronology of warm core ring 82b a chronology constructed from satellite derived thermal imagery is presented to describe the formation and life history of warm core ring 82b this overview provides insight into a classification of features and discrete events associated with gulf stream warm core rings and allows these events as well as our limited shipboard observations to be placed in a broader spatial and temporal context than would otherwise be possible without the satellite data events influencing the evolution of 82b include environmental factors such as meteorological influences and gulf stream interactions as well as those stimulated by encounters with changes in bottom topography the interactions of the ring with surrounding waters are especially noteworthy and the existence of vortex vortex interactions is shown to be a significant cause of local water advection through streamer activity ring events are documented by following changes in ring size shape translation and surface thermal structure our satellite observations are supported by extensive contemporaneous shipboard observations including xbt ctd bops biooptical profiling system temperature profiles and along track sea surface temperature measurements in addition acoustic velocity profiling and drifter trajectories have been used to corroborate hydrographic features of the ring and environs these ship and satellite data form a coherent space time overview of the ring and its environment and show them to be closely related and continually interacting

strong vertical mixing in the urup strait 1 microstructure measurements were conducted in one of the kuril straits in the summer of 2007 over the course of 1 day of repeated observations across the pacific side of the steep sill of the urup strait extremely strong mixing was observed during periods of pacific ward down sill flows and during the transition from pacific ward to okhotsk ward up sill flows with a turbulent energy dissipation rate of 10 6 to 10 5 w kg 1 and vertical diffusivity of 10 1 to 5 10 1 m2 s 1 during the period of strong mixing we observed homogeneous layers with a thickness of 300 600 m and potential density of 26 6 26 7 occupying the entire water column in one case high values of within this layer indicate the injection of diapycnal flows from the upper and lower layers possibly contributing to southward intrusion of intermediate water into the subtropical gyre

anticyclonic rings in the gulf of mexico abstract using the historical data set this study describes the anticyclonic rings that separated from the loop current in the eastern gulf of mexico six quasi synoptic data sets are used to describe the evolving circulation of the gulf of mexico from october 1966 to september 1967 showing the separation and movement into the western gulf of three anticyclonic rings the historical data are used to determine that these rings typically translate to the west at a mean speed of 2 1 km day 1 their length scale as defined by their rms radii is 183 km an estimate of ring life span as defined by an e folding time is one year within the context of the gulf s water property distributions these rings appear as warm salty bodies the heat and salt added by one of these rings after separation are estimated to be 7 109 j m 2 and 17 g cm 2 respectively the heat and salt added by one of these features play an important role in the heat and salt budget of the western gulf the latter indicates that about one r

quantitative edxrf studies of obsidian sources in northern hokkaido quantitative trace element data from six obsidian sources on the japanese island of hokkaido is presented previous work by japanese scholars has utilized neutron activation analysis naa focusing on the rare earth elements or qualitative energy dispersive x ray fluorescence edxrf in this study non destructive edxrf is used to generate trace element data for 9 elements bivariate plots of the incompatible trace elements ba rb sr y and zr can be used to separate the obsidian sources in this study source separation was confirmed by using linear discriminant analysis stepwise discriminant analysis indicates that ba sr rb ti y and zr are the most discriminating elements

palynomorphs of the fezouata shale lower ordovician morocco age and environmental constraints of the fezouata biota abstract the present study documents new palynological investigations of the fezouata shale from the anti atlas morocco palynomorphs were extracted from samples collected from both outcrops and drill cuttings outcrop samples were taken near zagora and include some that were collected during excavation of stratigraphic horizons where exceptionally well preserved fossils of the fezouata lagerstatte occur subsurface samples were taken from the az 1 adrar zouggar mountain borehole which was extracted some 300 km to the southwest of zagora the palynological samples yielded acritarchs chitinozoans scolecodonts conodonts and fragments of graptolites the abundance and quality of preservation of palynomorphs varies greatly but rich and diverse assemblages were recovered from several samples the diversity and composition of the assemblages points to an open shelf environment generally mixed preservation states suggest resedimentation or differential transport histories the acritarchs can be assigned to the diagnostic messaoudensis trifidum acritarch assemblage which is typical of the tremadocian floian boundary interval of the gondwanan margin in high southern palaeolatitudes the acritarch taxa present in some of the lower parts of the fezouata shale including levels of exceptional preservation can be attributed to sub assemblages 1 2 of the messaoudensis trifidum assemblage and thus point to a late tremadocian age of the fezouata lagerstatte confirming biostratigraphic data provided by graptolites of the araneograptus murrayi graptolite biozone chitinozoans from the fezouata shale are from the e symmetrica and e brevis biozones and include various species that are well known from several localities on the gondwanan margin and from other palaeocontinents baltica laurentia and south china demarcating broad links between those regions the coincidence between index fossils of these three groups hitherto not all found in the same level suggests that the age assignments of chitinozoan biozones may be in need of revision

an early ordovician age for the annascaul formation of the se dingle peninsula sw ireland the phyllitic mudrocks quartz wacke sandstones and melange units of the annascaul formation in the se dingle peninsula sw ireland have been previously assumed to be silurian in age similar to overlying fossiliferous wenlock rocks of the ballynane member the contact between the ballynane member and the underlying annascaul beds is either faulted or unconformable and the annascaul mudrocks contain two or more cleavages not present in the silurian ballynane and younger strata the ballynane member is therefore differentiated from the annascaul formation by upgrading the proven wenlock ballynane beds to formational status grey and black mudrocks in the annascaul formation have yielded diagnostic palynomorph assemblages indicative of an early ordovician age the annascaul formation invites comparison with similar early ordovician rocks south of the putative trace of the iapetus suture in se and eastern ireland in the english lake district and in central newfoundland

upper ocean thermal structure and the western north pacific category 5 typhoons part i ocean features and the category 5 typhoons intensification abstract category 5 cyclones are the most intense and devastating cyclones on earth with increasing observations of category 5 cyclones such as hurricane katrina 2005 rita 2005 mitch 1998 and supertyphoon maemi 2003 found to intensify on warm ocean features i e regions of positive sea surface height anomalies detected by satellite altimeters there is great interest in investigating the role ocean features play in the intensification of category 5 cyclones based on 13 yr of satellite altimetry data in situ and climatological upper ocean thermal structure data best track typhoon data of the u s joint typhoon warning center together with an ocean mixed layer model 30 western north pacific category 5 typhoons that occurred during the typhoon season from 1993 to 2005 are systematically examined in this study two different types of situations are found the first type is the situation found in the western north pacific south eddy zone sez 21 26 n 127 170 e and the kuroshio 21 30

prediction and diagnosis of the motion and rapid intensification of typhoon sinlaku during tropical cyclone structure experiment 2008 tcs08 abstractthe impact of initial structure on storm evolution is examined for the case of a tropical storm entering rapid intensification at the onset of rapid intensification satellite cloud signatures suggest that the structural organization of typhoon sinlaku 2008 was dominated by a primary band of convection present at outer radii the development of the eyewall subsequently occurred within this band of deep convection numerical forecasts of sinlaku are initialized at 15 and 5 km resolution using a broad range of vortex scales at a time when the storm was still weak and its structure not clearly defined evidence is presented that beta propagation played a key role in changing the storm s motion under weak environmental steering it is found that the track forecast improves over the period when beta propagation is prominent if the vortex is initialized with a large radius of maximum wind rmw corresponding with the primary outer cloud band the initial vortex structure is also suggested to play a

upper ocean variability in the bay of bengal during the tropical cyclones nargis and laila upper ocean variability at different stages in the evolution of the tropical cyclones nargis and laila is evaluated over the bay of bengal bob during may 2008 and may 2010 respectively nargis initially developed on 24 april 2008 intensified twice on 27 28 april and 1 may and eventually made landfall at myanmar on 2 may 2008 laila developed over the western bob in may 2010 and moved westward towards the east coast of india data from the argo profiling floats the research moored array for african asian australian monsoon analysis and prediction rama and various satellite products are analyzed to evaluate upper ocean variability due to nargis and laila the analysis reveals pre conditioning of the central bob prior to nargis with warm 30 c sea surface temperature sst low 33 psu sea surface salinity sss and shallow 30 m mixed layer depths during march april 2008 enhanced ocean response to the right of the storm track due to nargis includes a large sst drop by 1 76 c sss increase up to 0 74 psu mixed layer deepening of 32 m shoaling of the 26 c isotherm by 36 m and high net heat loss at the sea surface during nargis strong inertial currents up to 0 9 ms 1 were generated to the right of storm track as measured at a rama buoy located at 15 n 90 e producing strong turbulent mixing that lead to the deepening of mixed layer this mixing facilitated entrainment of cold waters from as deep as 75 m and together with net heat loss at sea surface and cyclone induced subsurface upwelling contributed to the observed sst cooling in the wake of the storm a similar upper ocean response occurs during laila though it was a significantly weaker storm than nargis

transport reversals at taiwan strait during october and november 1999 1 the observed transport reversals at taiwan strait during october and november 1999 are examined by analytic solutions a numerical ocean model and the prediction from a real time north pacific ocean data assimilating model wind stress explains a majority of the transport reversals the reversals are forced by a combination of the local wind and the remote wind in the yellow and east china seas the connection between the yellow and east china seas wind stress and transport reversals at taiwan strait is provided by coastally trapped waves the waves are generated by the northerly winter wind bursts in the yellow sea and are enhanced in the east china sea by alongshore northerly wind

acritarch marine microphytoplankton diversity in an early ordovician deep water setting the skiddaw group northern england implications for the relationship between sea level change and phytoplankton diversity early ordovician acritarch microphytoplankton assemblages from an outer shelf to slope facies in northern england show changes in diversity that parallel changes in sea level with high diversity occurring during lowstands and low diversity during highstands the pattern is the reverse of that recorded in the literature in which high acritarch diversity in continental platform successions has been related to periods of transgression and highstand and low diversity to periods of regression and lowstand the apparent contradiction can be explained if high diversity assemblages move further onto continental platforms during transgression and highstand but towards basins during regression and lowstand the hypothesis that high diversity acritarch assemblages track onshore and offshore during episodes of sea level change implies that there is a direct causal link between sea level and microphytoplankton diversity at least in so far as changes in sea level influence the location of high diversity the direct physical influence of sea level change on phytoplankton diversity might have been restricted to relatively small scales however its most obvious effect being perhaps to shift the locus of maximum diversity rather than affect the overall level of diversity at larger temporal and spatial scales the direct influence of sea level change on acritarch diversity is less certain parallel large scale changes in sea level and phytoplankton diversity have been documented for the phanerozoic as a whole but possibly reflect either independent responses to other factors such as the effects of tectonic cycles and changes in palaeogeography ocean circulation and climate or else indicate an indirect influence in the sense that sea level rise created conditions under which phytoplankton diversity could increase in contrast to the results discussed in this paper other analyses of ordovician acritarch diversity at larger spatial scales than those considered here have concluded that there is no evidence for any causal link between sea level change and diversity if however the controls on diversity exerted directly by changes in sea level are scale dependent and only apparent at relatively small scales analyses at larger spatial scales that compile measures of diversity across a range of depositional environments i e that sample both onshore and offshore environments and combine the results might not evince a correlation between changes in sea level and diversity in addition to producing shifts in the location of high diversity assemblages sea level changes also appear to be accompanied by at least local turnover in species composition during the early ordovician in northern england the high diversity assemblages associated with lowstands are very different in composition elsewhere in cratonic settings maximum flooding intervals within successive early palaeozoic stratigraphic sequences are characterised by markedly different acritarch assemblages hence changes in sea level appear to be associated with local extinctions and originations as well as changes in the locus of high diversity possibly as a result of ecological stresses arising from changes in the location of acritarch assemblages

topex poseidon observations of mesoscale eddies over the subtropical countercurrent kinematic characteristics of an anticyclonic eddy and a cyclonic eddy 1 relative dynamic heights and geostrophic fields were derived from topex poseidon altimetry data and then used to track mesoscale eddies over the subtropical countercurrent stcc the radii centers vorticities shearing deformation rates stretching deformation rates divergences and center velocities of all identified eddies over the stcc were determined using a model that assumes constant velocity gradients most eddies are concentrated in a zonal band near 22 n and there is an interannual variation in the number of eddies a case study was made for a cyclonic eddy and an anticyclonic eddy with time series of eddy kinematic parameters computed both eddies survive for 220 days and propagate westward along over 22 n 24 n to reach the kuroshio current east coast of taiwan where the eddies were dissipated and in turn affected the kuroshio current in many ways sea surface temperature data and drifter data confirm the existence of these two eddies the radii of both eddies vary and their shapes are mostly elliptical during propagation the anticyclonic eddy propagated almost westward with oscillating north south components and the mean speed is 8 3 km day the cyclonic eddy moved southwestward before reaching 130 e and then moved northwestward with a mean speed of 7 6 km day the propagations of these two eddies are basically consistent with the standard theory of eddy propagation but with larger speeds the propagating direction could be altered while passing steep bottom topography or merging with the other eddies index terms 4520 oceanography physical eddies and mesoscale processes 4576 oceanography physical western boundary currents 4512 oceanography physical currents 4594 oceanography physical instruments and techniques 4556 oceanography physical sea level variations

characterization of the zooplankton community size composition and distribution in relation to hydrography in the japan east sea abstract the japan east sea jes may be thought of as a model or microcosm of larger oceanic systems where biogeographic boundaries juxtapose at highly dynamic boundaries the northern and southern portions of the jes are hydrographically and biologically distinct with the southern portion being more tropical oligotrophic and the northern portion being more boreal eutrophic regional zooplankton taxonomic and size compositions and abundance and the high resolution vertical distribution of plankton fluorescence and coincident hydrography were described using the video plankton recorder vpr equipped with high and low magnification cameras and environmental sensors and mounted on a vertically profiling towed vehicle in the upper 80 m of the jes during the summer of 1999 a survey was conducted over both the northern and southern regions including the subpolar front spf that spanned 10 12 of latitude and longitude and covered an along track distance of 7000 km plankton also were collected at 15 selected stations using a ring net for silhouette analysis of taxa and size distributional patterns in abundance liter of plankton taxa from the vpr were quantified at sea in real time identifying plankton automatically using a neural network classifier the most abundant taxa identified were copepods oithona spp calanus spp copepod nauplii protozoa and diatoms with copepods the dominant taxon the northern jes southern jes and north korean cold current were distinct based on based on temperature salinity properties the hydrography was complex and characterized by multiple mesoscale features including currents and the meandering of the spf different taxonomic and size compositions were observed in the three hydrographic regions the vertical distributions of copepods and fluorescence were associated with hydrographic structure especially at fronts plankton abundances varied with regional hydrographic region and environmental conditions although strong associations were not always observed the extremely dynamic nature of the jes may effectively mix the plankton and obscure strong gradients or differences between regions

dynamical and physical processes leading to tropical cyclone intensification under upper level trough forcing abstractthe rapid intensification of tropical cyclone tc dora 2007 southwest indian ocean under upper level trough forcing is investigated tc trough interaction is simulated using a limited area operational numerical weather prediction model the interaction between the storm and the trough involves a coupled evolution of vertical wind shear and binary vortex interaction in the horizontal and vertical dimensions the three dimensional potential vorticity structure associated with the trough undergoes strong deformation as it approaches the storm potential vorticity pv is advected toward the tropical cyclone core over a thick layer from 200 to 500 hpa while the tc upper level flow turns cyclonic from the continuous import of angular momentum it is found that vortex intensification first occurs inside the eyewall and results from pv superposition in the thick aforementioned layer the main pathway to further storm intensification is associated with secondary eyewall formation triggered by external

numerical experiments on the movement of a warm core ring with the bottom slope of a western boundary numerical experiments are performed to investigate the effects of the bottom slope of a western boundary on realistic warm core rings using a primitive equation sigma coordinate model warm core rings which initially have baroclinic velocity near a steep bottom slope gradually move northward but those with barotropic velocity do not barotropic velocity on the slope immediately disperses as a topographic rossby wave while baroclinic velocity is retained since the northward movement is caused by an effect very much like the image effect which is originally the effect of a free slip wall the authors term this effect the equivalent image effect the equivalent image effect increases as a slope becomes steeper and bottom friction becomes weaker and vice versa it seems that a steep slope acts like a wall and the bottom friction of a steep slope corresponds to the lateral viscous effect of a wall however the effect of a slope on a warm core ring is different from that of a wall in that ring slope interactions take place at the lower part of the ring because the velocity of a warm core ring is weak in deep layers ring slope interactions are moderate and the leakage of the interior fluid of a ring seen in ring wall interactions is not apparent while the viscous effect is weaker than that of a no slip wall as well these results are applied to the northward movement of kuroshio warm core rings and to warm eddies in the gulf of mexico

water mass structure of warm and cold anticyclonic eddies in the western boundary region of the subarctic north pacific vertical profile data of temperature and salinity from various sources were analyzed together with satellite altimeter data to investigate the water mass characteristics of warm and cold anticyclonic eddies in the western boundaryregionof the subarctic north pacific a densedistributionof anticyclonic eddieswith warm and saline core water occurred near the kuroshio extension and the distribution extends northward northeastward into the western subarctic gyre along the japan and kuril kamchatka trenches eddies with cold and fresh core water are found mainly around the oyashio southward intrusions and farther north near the kuril islands based on the heat content anomaly integrated over 50 200 dbar 85 of the anticyclonic eddies within the study area 358 508n 1408 1558e have a warm and saline core and 15 have a cold and fresh core warm and saline eddies around the japan and kuril kamchatka trenches have a double core structure with a cold and freshwater mass located below the warm core the northward propagation of these eddies along the trench line results in a large northward heat salinity transport in the upper 400 dbar 250 dbar and a negative salinity transport below 350 dbar the lower core water is colder and fresher on isopycnal surfaces at around 26 70sucompared with the climatology given that the 26 70su isopycnal surface does not outcrop in the open north pacific an alignment process is suggested to occur between the warm and saline and the cold and fresh anticyclonic eddies in the upper and intermediate layers respectively

upper ocean thermal structure and the western north pacific category 5 typhoons part ii dependence on translation speed abstract using new in situ ocean subsurface observations from the argo floats best track typhoon data from the u s joint typhoon warning center an ocean mixed layer model and other supporting datasets this work systematically explores the interrelationships between translation speed the ocean s subsurface condition characterized by the depth of the 26 c isotherm d26 and upper ocean heat content uohc a cyclone s self induced ocean cooling negative feedback and air sea enthalpy fluxes for the intensification of the western north pacific category 5 typhoons based on a 10 yr analysis it is found that for intensification to category 5 in addition to the warm sea surface temperature generally around 29 c the required subsurface d26 and uohc depend greatly on a cyclone s translation speed it is observed that even over a relatively shallow subsurface warm layer of d26 60 70 m and uohc 65 70 kj cm 2 it is still possible to have a sufficient enthalpy flux to intensify the storm to category 5

limitation of one dimensional ocean models for coupled hurricane ocean model forecasts abstract wind stress imposed on the upper ocean by a hurricane can limit the hurricane s intensity primarily through shear induced mixing of the upper ocean and subsequent cooling of the sea surface since shear induced mixing is a one dimensional process some recent studies suggest that coupling a one dimensional ocean model to a hurricane model may be sufficient for capturing the storm induced sea surface temperature cooling in the region providing heat energy to the hurricane using both a one dimensional and a three dimensional version of the same ocean model it is shown here that the neglect of upwelling which can only be captured by a three dimensional ocean model underestimates the storm core sea surface cooling for hurricanes translating at 5 m s 1 for hurricanes translating at 2 m s 1 more than half of the storm core sea surface cooling is neglected by the one dimensional ocean model since the majority of hurricanes in the western tropical north atlantic ocean translate at 5 m s 1 the

numerical simulation of tropical cyclone mora using a regional coupled ocean atmospheric model tropical storms ts are highly sensitive to the behavior of nearby oceans and the only way to improve their predictability is to include all the possible factors contributing to their genesis and motion the present study evaluates the response of air sea coupling on ts mora which occurred during the pre monsoon season of 2017 mora is simulated using a non hydrostatic regional atmospheric modeling system coupled to a regional ocean modeling system model the observations show a low level rossby wave in the atmosphere during the storm genesis there was also evidence of increased sea surface height simultaneously in the form of a downwelling kelvin wave at the west coast of the bay of bengal the present study emphasizes the relationship between near surface oceanic and atmospheric circulation patterns we have tried to elucidate the process with the help of dynamical equations and model solutions we also analyze the pivotal role of the atmospheric rossby wave in the formation of the coastal kelvin wave the kelvin wave seems to produce a warm pool required to form a low pressure system which further gave rise to the tropical storm mora the changes in the temperature and salinity profile within the ocean subsurface layers during storm passage are further used for inferences regarding the vertical structure of the upper ocean due to wind generated mixing the model analysis reveals that the ocean and atmospheric counterparts responsible for storm genesis are well recorded in the coupled model when compared to the observations it was found that air sea coupling in the model made it possible to realistically capture ocean and atmospheric responses

temperature inversions in the subarctic north pacific abstract hydrographic data from the world ocean database 2001 and argo profiling floats were analyzed to study temperature inversions in the subarctic north pacific ocean the frequency distribution of temperature inversions f t inv at a resolution of 1 latitude 3 longitude was calculated temperature inversions seldom occurred around 50 n in the eastern subarctic north pacific but were more common in the northern gulf of alaska and the southeastern subarctic north pacific 42 48 n 140 170 w large temperature inversions occurred throughout the year in the western and central subarctic north pacific north of 42 n and west of 180 except near the aleutian and kuril islands near those islands f t inv was characterized by pronounced seasonal variations forced by surface heating cooling and strong tidal mixing

fine and microstructure observations in the urup strait kuril islands during august 2006 1 for the first time we performed continuous observations of turbulent mixing upon the sill of the urup strait kuril islands for a period of 1 day during august of 2006 time series of velocity profiles water properties and isopycnal depths show variability with a period of about 1 day however the water mass variability is not explained by simple water exchange between the sea of okhotsk and the north pacific empirical orthogonal function eof analysis of isopycnal coordinates extracted variability presumed to represent tidal flows as major eofs in profiles of the residual flow after subtracting the mean flow and major eofs we detected phase propagations consistent with internal gravity waves with an approximate period of 9 1 11 4 h the turbulent energy dissipation rate and vertical diffusivity k ranged from 1 10 9 to 3 10 8 w kg 1 and from 3 10 5 to 2 10 3 m2s 1 respectively occurrences of high dissipation rates generally corresponded to either strong shear or weak stratification a significant contribution of shear s to the dissipation rate was indicated with a relationship of s1 4 s1 8 probably related to propagating internal waves a strong mixing event was observed within the water column with extremely weak stratification and a richardson number below the critical value of 0 25 when the flow direction changed from up sill to down sill

eddy induced heat transport in the subtropical north pacific from argo tmi and altimetry measurements basin scale heat transport induced by mesoscale oceanic eddies is estimated by combining satellite derived sea surface height and temperature temperature data are from the trmm microwave imager tmi data with argo float temperature salinity data in the north pacific ocean subtropical gyre warm cold temperature anomalies of mesoscale eddies are found to be consistently located to the west of high low ssh anomalies the phase misalignment between the temperature and velocity anomalies however is largely confined to the seasonal thermocline causing most of the eddy induced heat transport to be carried in the surface 200 m layer by establishing a statistical relationship between the surface and depth integrated values of the eddy heat transport the basin scale eddy heat transport is derived from the concurrent satellite ssh sst data of the past six years in the kuroshio extension region the meandering zonal jet is found to generate oppositely signed eddy heat fluxes as a result the zonally integrated poleward heat transport associated with the kuroshio extension is at a level o 0 1 pw smaller than the previous estimates based on turbulent closure schemes large poleward eddy heat transport is also found in the subtropical north pacific along a southwest northeast tilting band between taiwan and the midway islands this band corresponds to the region of the subtropical front and it is argued that the relevant temperature field for identifying this band in the turbulent closure scheme models should be that averaged over the seasonal thermocline

a coupled atmosphere wave ocean modeling system simulation of the intensity of an idealized tropical cyclone abstract a coupled atmosphere wave ocean modeling system cawoms based on the integration of atmosphere wave atmosphere ocean and wave current interaction processes is developed the component models consist of the weather research and forecasting wrf model the simulating waves nearshore swan model and the princeton ocean model pom the coupling between the model components is implemented by using the model coupling toolkit the cawoms takes into account various wave related effects including wave state and sea spray affected sea surface roughness sea spray heat fluxes and dissipative heating in atmosphere wave coupling it also considers oceanic effects such as the feedback of sea surface temperature sst cooling and the impact of sea surface current on wind stress in atmosphere ocean coupling in addition wave current interactions including radiation stress and wave induced bottom stress are also taken into account the cawoms is applied to the simulation of an idealized tropical cyclo

the transition region mode water of the north pacific and its rapid modification abstractusing argo float data this study examined the formation region spatial distribution and modification of transition region mode water trmw which is a recently identified pycnostad in the subtropical subarctic transition region of the north pacific the basin scale boundary region between subtropical and subarctic water masses analyses of the formation fields of water masses within and around the transition region reveal that trmw forms in a wide area from the western to central transition region and is separated from the denser variety of central mode water d cmw to the south by a temperature and salinity front trmw has temperatures of 4 9 c and salinities of 33 3 34 0 making it colder and fresher than d cmw trmw has a density range of 26 3 26 6 and thick trmw is widely distributed in the transition region however the range of the t s properties at trmw cores is substantially reduced downstream within 10 20 longitude from the formation region by gradually losing its fresh and c

acritarch dating of latest tremadoc earliest arenig early ordovician sediments in the carmarthen district south wales an acritarch assemblage from beds beneath the ogof hen formation near carmarthen the login beds resembles assemblages from the watch hill grits and underlying sediments of latest tremadoc or earliest arenig age in the skiddaw group of the english lake district we conclude that the login acritarch assemblage is younger than at least some part of the late tremadoc angelina sedgwickii biozone but older than the early arenig didymograptus deflexus biozone its occurrence may therefore coincide with that of the graptolite tetragraptus approximatus this is of particular significance in any attempt to define an internationally correlatable base for the arenig series in britain

distribution and modification of north pacific intermediate water in the kuroshio oyashio interfrontal zone abstract a multiship ctd survey was conducted in the kuroshio oyash interfrontal zone in the area of 30 41 n 140 e 180 from may to june 1992 to examine the distribution modification process and formation site of north pacific intermediate water npiw low salinity oyashio water and high salinity kuroshio water merge along the kuroshio extension just off the east coast of japan and together flow eastward eastward geostrophic transport and salinity across the kuroshio strong current indicate that the mixture of the kuroshio and oyashia waters along the kuroshio extension can produce new npiw transport estimate suggests that the new npiw bifurcates into the interfrontal zone and into the recirculation of the subtropical gyre a salinity minimum structure can he also created due to the isopycnal mixing along the kuroshio extension between the oyashio and kuroshio waters which have different salinity and vertical velocity structures the low salinity oyashio water seen along the oyashio branches and t

the end ordovician glaciation and the hirnantian stage a global review and questions about late ordovician event stratigraphy abstract this paper proposes a global review of hirnantian event stratigraphy the hirnantian gssp in south china is tentatively correlated with latest ordovician strata from the peri gondwanan glacial regions problems of biostratigraphical correlation are highlighted at a worldwide scale the major biostratigraphically useful fossil groups graptolites chitinozoans brachiopods conodonts acritarchs are analysed and their limits for global correlation of the uppermost ordovician are discussed palaeobiogeographical disparities are invoked as the primary cause of the difficulty in establishing an effective late ordovician global biostratigraphical scheme as an alternative correlative tool the hice hirnantian isotopic curve excursion event is often put forward in the literature however carbon isotope chemostratigraphy shows like biostratigraphy some limits to the present state of knowledge no good independent biostratigraphical control of the hice exists in both shallow carbonate deposits and deeper shaly ones recent studies have also demonstrated inconsistencies between carbon isotopic signals obtained from organic 13corg and inorganic 13ccarb carbon species further complicating the use of the hice as an isochronous benchmark all of these difficulties for hirnantian event stratigraphy are discussed in detail in order to enable them to be overcome in the future precise late ordovician and early silurian event stratigraphies are essential for the understanding of the mechanisms linked to the first of the big five extinctions

variability in the deep western boundary current local versus remote forcing 1 horizontal velocity temperature and salinity measurements from the line w array for the period 2004 2008 show large changes in the water mass structure and circulation of the deep western boundary current dwbc fluctuations in the flow with periods from 10 to 60 days are bottom intensified signals most likely associated with topographic rossby waves trw a fraction 15 of the dwbc transport variability is caused by gulf stream rings and meanders these flow anomalies are surface intensified and fluctuate at frequencies lower than the trw interannual variability in the velocity field appears to be related to changes in the hydrographic properties the dominant mode of variability is characterized by an overall freshening cooling a potential vorticity pv increase in the deep labrador sea water dlsw and a pv decrease in the overflow water ow the variability in the flow associated with these property changes is not spatially homogeneous offshore water depths larger than 3500 m changes in the velocity are in phase with pv changes in the ow a decrease in the ow pv is accompanied by an increase in the southward negative transport conversely variations of the inshore flow are in phase with changes in the dlsw pv increasing pv and decreasing transport this trend true for most of the record reverses after the winter of 2007 2008 a sudden decrease of the dlsw pv is observed with a corresponding intensification of the flow in the inner dwbc as well as a northward shift in the gulf stream axis

a study of the interaction between typhoon francisco 2013 and a cold core eddy part i rapid weakening abstracttyphoon francisco 2013 experienced unusually rapid weakening rw with its maximum surface wind decreasing by 45 kt 1 kt 0 51 m s 1 over 24 h as measured from the satellite derived ad

the messaoudensis trifidum acritarch assemblage and correlation of the base of ordovician stage 2 floian the global stratotype section and point gssp for stage 2 of the ordovician system now the floian stage and approximately equivalent to the lower and middle arenig of england and wales is defined by the first appearance datum fad of the graptolite tetragraptus approximatus in the diabasbrottet quarry section at mount hunneberg sweden one of the issues this raises is how to correlate the base of stage 2 at the gssp with areas and successions that do not contain a correlative graptolite fauna the distinctive cymatiogalea messaoudensis stelliferidium trifidum acritarch assemblage is present in the upper tremadocian araneograptus murrayi graptolite biozone of nw england and ranges across the tremadocian stage 2 boundary there the tremadoc arenig boundary of anglo welsh nomenclature it also occurs widely at other high southern ordovician palaeolatitudes around the margin of gondwana being reported from ireland wales the isle of man belgium germany spain and turkey and may also be present in bohemia and argentina eastern cordillera it therefore has the potential to contribute towards the recognition and correlation of the base of stage 2 in those areas of particular interest are the first appearance datums of various taxa within the stratigraphical range of the messaoudensis trifidum assemblage notably that of aureotesta clathrata simplex which is considered to be close to the base of stage 2 in nw england elements of the messaoudensis trifidum assemblage also occur in baltica the palaeoplate on which the gssp for the base of stage 2 is located however many of the taxa used to subdivide the messaoudensis trifidum assemblage around gondwana have not been recorded from baltica and may be restricted palaeobiogeographically to the gondwanan margin furthermore acritarch microfloras have not been reported from the diabasbrottet quarry section itself and there are hiatuses across the base of stage 2 in the two sections from baltica considered in this paper hence direct correlation of the base of stage 2 between the gssp and other sections using acritarchs is not yet possible nevertheless some taxa for example the genera peteinosphaeridium and rhopaliophora are shown to have fads at similar stratigraphical levels in the late tremadocian stage of both baltica and gondwana and therefore have the potential to correlate time slices in the late tremadocian stage between palaeoplates

motion and evolution of oceanic rings in a numerical model and in observations observed properties of oceanic rings are compared to rings produced in a two gyre wind driven numerical ocean model and in a model of the south atlantic indian ocean their temporal evolution is discussed in terms of structure and translation rate they exhibit substantial similarity in terms of thermocline depth ring size swirl velocities and translations speeds in both observations and numerical model results the propagation speeds are 2 to 5 times faster than that of an equivalent isolated eddy which is of the order of the long rossby wave speed this is attributed to advection by the mean flows furthermore it is observed that the model rings have a coherent structure all the way to the bottom there is strong evidence that this is also the case in real oceanic rings one major difference between observed and modeled rings is in their decay rate the temporal decay of the rings in the models and observations is therefore discussed in relation to the decay mechanisms at work and the frictional parameterization of the model

correlation for the lower palaeozoic the global correlation standards now agreed for the ordovician and silurian systems and partly so for the cambrian system are summarized correlation of the international series and stages with the traditional and revised british series and stages is reviewed as well as with those in north america laurentia

satellite derived ocean thermal structure for the north atlantic hurricane season abstractthis paper describes a new model method called satellite derived north atlantic profiles snap that seeks to provide a high resolution near real time ocean thermal field to aid tropical cyclone tc forecasting using about 139 000 observed temperature profiles a spatially dependent regression model is developed for the north atlantic ocean during hurricane season a new step introduced in this work is that the daily mixed layer depth is derived from the output of a one dimensional price weller pinkel ocean mixed layer model with time dependent surface forcing the accuracy of snap is assessed by comparison to 19 076 independent argo profiles from the hurricane seasons of 2011 and 2013 the rms differences of the snap estimated isotherm depths are found to be 10 25 m for upper thermocline isotherms 29 19 c 35 55 m for middle isotherms 18 7 c and 60 100 m for lower isotherms 6 4 c the primary error sources include uncertainty of sea surface height anomaly ssha high frequency fluc

sources of archaeological obsidian on sakhalin island russian far east abstract instrumental neutron activation analysis was performed on 79 obsidian tools and flakes from 35 sites on sakhalin island dating from upper paleolithic c 19 000 bp to early iron age c 2000 800 bp due to the absence of volcanic glass on sakhalin island raw materials from the nearest obsidian sources on hokkaido island such as oketo shirataki tokachi mitsumata and akaigawa were also analysed a strong correlation between the chemical compositions of obsidian artefacts from sakhalin and volcanic glass sources from hokkaido was discovered in particular the oketo and shirataki sources were used for tool manufacturing throughout all of sakhalin island s prehistory the distances between sources and archaeological sites range from 200 1000 km the intensive exchange of raw materials continued and even intensified after the appearance of the la perouse soya strait between hokkaido and sakhalin about 10 000 8000 bp the sakhalin island populations were deeply involved in the obsidian exchange network centered on hokkaido

baroclinic eddy interactions with continental slopes and shelves abstract the evolution and propagation of large anticyclonic eddies similar to the loop current eddies found in the gulf of mexico are studied in a two layer intermediate equation numerical model it is found that the propagation of these eddies is governed primarily by the effect lower layer flow driven by the surface eddies and the image effect as the eddies move westward under the influence of the effect they drive deep circulation that typically includes a cyclone near the eddies trailing edge this cyclone accelerates the eddy southward leading to a path substantially different from that found in reduced gravity models of similar surface eddies when the eddy encounters a continental slope the lower layer flow is dispersed by topographic rossby waves and the eddy loses its southward propagation component if the continental slope is backed by a shelf that is wider than the eddy s radius a deep anticyclone will form over the shelf as the eddy approaches the shelf break this anticyclone w

impact of a warm ocean eddy s circulation on hurricane induced sea surface cooling with implications for hurricane intensity abstractupper oceanic heat content ohc in advance of a hurricane is generally superior to prestorm sea surface temperature sst for indicating favorable regions for hurricane intensification and maintenance ohc is important because a hurricane s surface winds mix the upper ocean and entrain cooler water into the oceanic mixed layer from below subsequently cooling the sea surface in the region providing heat energy to the storm for a given initial sst increased ohc typically decreases the wind induced sea surface cooling and a warm ocean eddy wcr has a higher ohc than its surroundings so conditions typically become more favorable for a hurricane to intensify when the storm s core encounters a wcr when considering hurricane intensity however one often neglected aspect of a wcr is its anticyclonic circulation this circulation may impact the location and magnitude of the hurricane induced sea surface cooling using an ocean model either prescribed hurricane wind stress or wind stress obtained

direct breaking of large amplitude internal waves in the urup strait abstract observations and model data have been analyzed for the urup strait one of the kuril straits focusing on processes driving the extremely strong vertical mixing observations over 1 day on the pacific side of the sill of the urup strait show the generation of a large amplitude internal wave laiw characterized by the depression of potential density surfaces caused by a strong off sill flow when the laiw developed the potential density surface of 26 7 was depressed downward by more than 300 m and vertical mixing was markedly elevated within the 400 m thick layer 26 6 26 7 with a layer mean maximum energy dissipation rate and vertical diffusivity of 1 2 10 6 7 9 10 6 w kg 1 and 4 0 10 1 2 8 m2 s 1 respectively a three dimensional model simulation of the kuril straits driven by the diurnal barotropic tide reproduces well the observed features relevant to the generation of laiws in and around the urup strait the structure and generation pattern of laiws in the urup strait are consistent with those of the arrested lee waves observed in the hawaiian ridge and luzon strait although the depth at the top of the sill is far shallower in the urup strait it is suggested that barotropic tidal energy with diurnal frequency is converted into laiws through the excitation of topographically trapped waves with hydraulically supercritical velocity near the sill top and it is these waves that are responsible for the extremely strong mixing on the sill flanks of the shallow kuril straits

influence of the size of supertyphoon megi 2010 on sst cooling abstractsupertyphoon megi 2010 left behind two very contrasting sst cold wake cooling patterns between the philippine sea 1 5 c and the south china sea 7 c based on various radii of radial winds we found that the size of megi doubles over the south china sea when it curving northwards on average the radius of maximum wind rmw increased from 18 8 km over the philippine sea to 43 1 km over the south china sea the radius of 64 kt typhoon force wind r64 increased from 52 6 km to 119 7 km the radius of 50 kt damaging force wind r50 increased from 91 8 km to 210 km and the radius of 34 kt gale force wind r34 increased from 162 3 km to 358 5 km to investigate the typhoon size effect we conduct a series of numerical experiments on megi induced sst cooling by keeping other factors unchanged i e typhoon translation speed and ocean subsurface thermal structure the results show that if it were not for megi s size increase over the south china sea the during megi sst cooling magnitude woul

rapid evolution of a gulf stream warm core ring gulf stream warm core rings form in the slope water between the north american continental shelf and the gulf stream by the separation of a north extending meander1 the initial physical chemical and biological properties of the core of these 100 200 km eddies are often similar to those of its parent water mass the sargasso sea a clockwise rotating remnant of the gulf stream circulates around the core with surface current speeds of 50 200 cm s 1 although warm core rings can slowly change over periods of months through interactions with the surrounding slope water gulf stream meanders continental slope other rings and the atmosphere we have now discovered that major alterations to ring structure can occur during very short periods 2 5 days when an interaction with the gulf stream is particularly intense such short period interactions between a ring and the gulf stream are a major factor governing a ring s evolution

modification of a kenai eddy along the alaskan stream 1 a kenai eddy was studied through analyses of satellite altimeter data and hydrographic data from shipboard and argo float observations this eddy formed in december 2006 south of the kenai peninsula and propagated southwestward along the alaskan stream the eddy held horizontally uniform warm core water in january 2007 in late winter 2007 this core water was cooled from the top and a subsurface temperature maximum was formed around 26 5 two years later in summer 2009 warm and low dissolved oxygen low do water characterized by a temperature maximum around 26 5 was observed again in the eddy core and was likely the remnant of original core water at the same time cold and high do water intrusions occurred in the eddy core suggesting that strong modification of core water was ongoing after summer 2009 the core water was fully changed through interaction with another eddy

variability of upper ocean characteristics and tropical cyclones in the south west indian ocean track and intensity are key aspects of tropical cyclone behavior intensity may be impacted by the upper ocean heat content relevant for tc intensification known as tdy and barrier layer thickness blt here the variability of tdy and blt in the south west indian ocean and their relationships with tropical cyclones are investigated it is shown that rapid cyclone intensification is influenced by large tdy values thick barrier layers and the presence of anticyclonic eddies for tc generation in the south west indian ocean the parameter tdy was found to be important large blt values overlay with large tdy values during summer both fields are modulated by the westward propagation of rossby waves which are often associated with enso for example the 1997 1998 el nino shows a strong signal in tdy sst and blt over the south west indian ocean after this event an increasing trend in tdy occurred over most of the basin which may be associated with changes in atmospheric circulation increasing sst power dissipation index and frequency of category 5 tropical cyclones also occurred from 1980 to 2010 to further examine the links between tropical cyclones tdy and blt the ocean response to category 5 tropical cyclone bansi that developed near madagascar during january 2015 was analyzed its unusual track was found to be linked with the strengthening of the monsoonal north westerlies while its rapid intensification from category 2 to category 4 was linked to a high tdy region associated with a warm core eddy and large blt

an investigation of the influences of mesoscale ocean eddies on tropical cyclone intensities abstractthe impact of mesoscale ocean eddies on tropical cyclone intensities is investigated based on a combination of observations and atmosphere ocean coupling simulations a statistical analysis reveals that the tropical cyclone eddy interactions occur at very high frequencies over 90 of the recorded tropical cyclones over the western north pacific have encountered ocean eddies from 2002 to 2011 the chances of confronting a cold core eddy cce are slightly larger than confronting a warm core eddy wce the observational sea surface temperature data have statistically evidenced that cces tend to promote the sea surface temperature decrease caused by tropical cyclones while wces tend to restrain such ocean responses the roles of cces are statistically more significant than those of wces in modulating the sea surface temperature response it is therefore proposed that cces should be paid no less attention than wces during the tc ocean interaction process the cce induced changes in sea surface tempe

the interaction of supertyphoon maemi 2003 with a warm ocean eddy understanding the interaction of ocean eddies with tropical cyclones is critical for improving the understanding and prediction of the tropical cyclone intensity change here an investigation is presented of the interaction between supertyphoon maemi the most intense tropical cyclone in 2003 and a warm ocean eddy in the western north pacific in september 2003 maemi passed directly over a prominent 700 km 500 km warm ocean eddy when passing over the 22 n eddy rich zone in the northwest pacific ocean analyses of satellite altimetry and the best track data from the joint typhoon warning center show that during the 36 h of the maemi eddy encounter maemi s intensity in 1 min sustained wind shot up from 41 ms 1 to its peak of 77 m s 1 maemi subsequently devastated the southern korean peninsula based on results from the coupled hurricane intensity prediction system and satellite microwave sea surface temperature observations it is suggested that the warm eddies act as an effective insulator between typhoons and the deeper ocean cold water the typhoon s self induced sea surface temperature cooling is suppressed owing to the presence of the thicker upper ocean mixed layer in the warm eddy which prevents the deeper cold water from being entrained into the upper ocean mixed layer as simulated using the coupled hurricane intensity prediction system the incorporation of the eddy information yields an evident improvement on maemi s intensity evolution with its peak intensity increased by one category and maintained at category 5 strength for a longer period 36 h of time without the presence of the warm ocean eddy the intensification is less rapid this study can serve as a starting point in the largely speculative and unexplored field of typhoon warm ocean eddy interaction in the western north pacific given the abundance of ocean eddies and intense typhoons in the western north pacific these results highlight the importance of a systematic and in depth investigation of the interaction between typhoons and western north pacific eddies

deep intense vertical mixing in the bussol strait 1 to reveal the intensity of deep mixing in the bussol strait we performed the direct observations of turbulence for the first time vigorous vertical mixing with a turbulent energy dissipation rate e above 10 6 w kg and diapycnal diffusivity k above 103 cm2 s were observed at depths of 600 1300 m potential densities of 27 0 27 5 at the western gap of the bussol strait possibly affecting water mass transformation and thermohaline circulation the strong vertical mixing with a diurnal period occurred when the diurnal tidal current flowed toward the okhotsk sea corresponding to a period of enhanced shear consisting of the mean flow with a two layered structure and the large amplitude diurnal tidal current with a vertical structure explained by a low vertical mode topographically trapped wave the empirical relationship ofe 10 1 46 1 91 s2 16 0 72 is obtained between e and the shear sreconstructed from the 50 m scale mean diurnal and semi diurnal tidal currents

late glacial bifacial microblade core technologies in hokkaido an implication of human adaptation along the northern pacific rim abstract the wedge shaped microblade core technology found along the northern pacific rim has been regarded as a trait of hunter gatherer adaptation during the late glacial and initial holocene having recognized variable microblade core reduction methods among the technocomplexes in hokkaido by employing an optimization model in lithic technology the present paper addresses the question of what role bifacial microblade core technologies played in foraging through a comparative analysis of utility cost of transportation and failure rates between the larger sakkotsu and smaller oshorokko bifacial microblade core technologies in the late glacial hokkaido results suggest that as opposed to the larger bifacial microblade core technology the smaller bifacial microblade core technology was more effective for exploring unpredictable environment across the northern pacific rim

air sea interaction between tropical cyclone nari and kuroshio 1 the air sea interaction between tropical cyclone nari sep 6 16 2001 and kuroshio is studied using satellite observations and an ocean model nari crossed the kuroshio several times which caused variations in typhoon intensity nari weakened when it was over the shelf north of kuroshio where cooling took place due to mixing of the shallow thermocline the cyclonic circulation penetrated much deeper for the slowly moving storm regardless of nari s intensity near inertial oscillations are simulated by the model in terms of the vertical displacement of isotherms the sst cooling caused by upwelling and vertical mixing is effective in cooling the upper ocean several days after the storm had passed at certain locations surface chlorophyll a concentration increases significantly after nari s departure upwelling and mixing bring nutrient rich subsurface water to the sea surface causing enhancement of phytoplankton bloom

an ocean coupling potential intensity index for tropical cyclones american geophysical union 2013 this article is posted here by permission of american geophysical union for personal use not for redistribution the definitive version was published in geophysical research letters 40 2013 1878 1882 doi 10 1002 grl 50091

effects of preexisting cyclonic eddies on upper ocean responses to category 5 typhoons in the western north pacific 1 this study examines the impacts of preexisting mesoscale cyclonic eddies pces on successive enhanced sea surface cooling in response to the passage of super typhoon hai tang in the western north pacific in 2005 using numerical simulation methods we have done two numerical experiments one with the presence of these pces resolved by the hybrid coordinate ocean model navy coupled ocean data assimilation system exphyc and another with world ocean atlas 2001 climatology as initial conditions expwoa the results show that the cooling response simulated by expwoa is only half of that simulated by exphyc which is close to satellite observations this suggests that an accurate representation of the upper dynamic conditions is required to estimate the sea surface cooling to a typhoon accurately subsequently the effects of the pces on successive cooling response to most major typhoons are evaluated by conducting a systematical analysis with a focus on category 5 typhoons occurring in the region from 2003 to 2008 satellite altimeter sea surface height anomaly data and merged tropical rainfall measuring mission microwave imager advanced microwave scanning radiometer for eos microwave sea surface temperatures sst are used to characterize pces and cooling responses to those typhoons the results identify the relationship between pces and successive enhanced sst cooling for most strong typhoons in the western north pacific

the lower ordovician fezouata konservat lagerstatte from morocco age environment and evolutionary perspectives abstract the lower ordovician fezouata konservat lagerstatte from southern morocco has been one of the major palaeontological discoveries of the last decade it provides a unique insight into one of the most critical periods in the evolution of marine life the cambrian ordovician transition however its potential for deciphering key trends in animal diversification was hitherto largely limited by major uncertainties concerning its stratigraphic position age and environmental setting based on extensive fieldwork fossil evidence and facies recognition our study provides clarification on these three crucial issues exceptional preservation is limited to two intervals within the fezouata shale graptolites indicate a late tremadocian age for the fezouata konservat lagerstatte as a whole which is supported by biostratigraphical evidence provided by acritarchs sedimentological features and reconstructed patterns of relative sea level changes indicate relatively shallow water environmental conditions under distal storm influence in an offshore to lower shoreface siliciclastic ramp setting the fezouata biota represents a unique and exceptional window into the palaeobiodiversity in open marine conditions thus contrasting with the other ordovician konservat lagerstatten presently known in our analyses of this new set of data we pave the way for accurate temporal faunal and environmental comparisons with other lower palaeozoic konservat lagerstatten and unlock the full potential of the fezouata biota to better understand the processes and scenarios of early animal radiations

tropical cyclone ocean interaction in typhoon megi 2010 a synergy study based on itop observations and atmosphere ocean coupled model simulations a mesoscale model coupling the weather research and forecasting model and the three dimensional price weller pinkel ocean model is used to investigate the dynamical ocean response to megi 2010 it is found that megi induces sea surface temperature sst cooling very differently in the philippine sea ps and the south china sea scs the results are compared to the in situ measurements from the impact of typhoons on the ocean in the pacific itop 2010 field experiment satellite observations and ocean analysis field from eastern asian seas ocean nowcast forecast system of the u s naval research laboratory the uncoupled and coupled experiments simulate relatively accurately the track and intensity of megi over ps however the simulated intensity of megi over scs varies significantly among the experiments only the experiment coupled with three dimensional ocean processes which generates rational sst cooling reasonably simulates the storm intensity in scs our results suggest that storm translation speed and upper ocean thermal structure are two main factors responsible for megi s distinct different impact over ps and over scs in addition it is shown that coupling with one dimensional ocean process i e only vertical mixing process is not enough to provide sufficient ocean response especially under slow translation speed 2 3 m s 1 during which vertical advection or upwelling is significant therefore coupling with three dimensional ocean processes is necessary and crucial for tropical cyclone forecasting finally the simulation results show that the stable boundary layer forms on top of the megi induced cold sst area and increases the inflow angle of the surface wind

human activity patterns at the horokazawa toma upper paleolithic stone tool manufacturing site in the shirataki obsidian source area combining excavation with experimentation abstract the horokazawa site locality toma ht is an upper paleolithic archeological site situated on a hillside near the shirataki akaishiyama obsidian source area the largest in japan excavations at ht over a period of more than 20 years have produced more than 570 000 artifacts from an area of less than 100 m2 the horokazawa toma lithic assemblage was characterized by the yubetsu technique which was used to manufacture microblades in siberia the far east and north america the assemblage at ht has been dated to the period just after the last glacial maximum around 15 000 years ago and when the microblade industry was flourishing in eastern asia as flakes and chips account for 98 of the lithic artifacts the site was evidently a lithic workshop in this study along with examination of excavated materials we identified the source of excavated materials by macroscopic observation and nondestructive analyses and we experimentally replicated the manufacturing technique to analyze the activities carried at this workshop and infer the distribution network of raw materials and worked stone beginning with the acquisition of the obsidian the obsidian came from the east atelier and ajisainotaki especially sources near the summit of mt akaishiyama large angular and slab like nodules from these sources were likely collected at hidarinosawa being closer to ht brought to ht and processed into large bifaces and boat shaped blanks for microblade manufacture many of these products were exported to other sites we showed by experiment that the first and second spalls efficiently removed from a large biface by the block on block technique a similar microblade industry based on shirataki obsidian is found at sites in the yubetsu river drainage below ht and other sites in hokkaido in fact shirataki obsidian is found at remote sites such as akatsuki site eastern part of hokkaido and sokol site on sakhalin island suggesting that raw materials were exchanged between groups of people over long distances this large distribution network was supported by mass production of blanks for microblade manufacturing at the toma locality of the horokazawa site

characteristics of mesoscale eddies in the kuroshio oyashio extension region detected from the distribution of the sea surface height anomaly abstract this study investigates the distribution of the sea surface height anomaly ssha with the aim of quantifying the characteristics of mesoscale eddies in the kuroshio oyashio extension region koer where intense mesoscale eddies are commonly observed during hydrographic surveys dense distributions of both anticyclonic eddies aes and cyclonic eddies ces are detected for the first time in koer with sufficient temporal and spatial coverage using the okubo weiss parameter without smoothing their contribution to the total ssha variance is estimated to be about 50 the zones of highest amplitudes are located north and south of the axis of the kuroshio extension ke for aes and ces which represent warm core and cold core rings respectively the areas extend poleward along the japan and kuril kamchatka trenches especially for aes eddies of both polarities and with moderate amplitudes are also recognized along the subarctic front saf eddies in areas north and south of the ke generally pro

three dimensional structure and temporal evolution of submesoscale thermohaline intrusions in the north pacific subtropical frontal zone abstract four instances of persistent intrusive deformation of the north pacific subtropical front were tagged individually by a lagrangian float and tracked for several days each feature was mapped in three dimensions using repeat towed observations referenced to the float isohaline surface deformations in the frontal zone included sheetlike folds elongated in the alongfront direction and narrow tongues extending across the front all deformations appeared as protrusions of relatively cold and fresh water across the front no corresponding features of the opposite sign or isolated lenslike structures were observed the sheets were o 10 m thick protruded about 10 km into the warm saline side of the front and were coherent for 10 30 km along the front having about the same thickness and cross frontal extent as the sheets tongues extended less than 5 km along the front all of the intrusions persisted as long as they were followed several days to one week their structures evolved on both inertial

agulhas eddies a synoptic view using geosat erm data abstract warm core rings formed in the agulhas retroflection transfer water from the indian ocean to the south atlantic in an attempt to measure the strength of this exchange a combination of satellite altimeter and hydrographic data are used to examine agulhas eddy paths and decay rates in the south atlantic because the surface dynamic height of a warm core eddy is higher than surrounding waters the rings are visible in satellite altimeter measurements over 20 agulhas eddies have been tracked from maps of anomalous sea surface height ssh derived from the geosat exact repeat mission erm dataset the correlation r2 of dynamic height referenced to 2000 dbar and anomaly ssh for one coincidentally sampled area is 97 within an agulhas eddy dropping to a fraction of that outside of it indicating that the ssh anomaly signal is a reliable measure for strong features like agulhas eddies the sizes and distribution of the agulhas eddies in the erm record compare favorably with those in recent hydrogr

the response of quasigeostrophic oceanic vortices to tropical cyclone forcing abstractthe response of quasigeostrophic qg oceanic vortices to tropical cyclone tc forcing is investigated using an isopycnic ocean model idealized oceanic currents and wind fields derived from observational data acquired during hurricane katrina are used to initialize this model it is found that the upwelling response is a function of the curl of wind driven acceleration of oceanic mixed layer oml currents rather than a function of the wind stress curl upwelling downwelling regimes prevail under the tc s eye as it translates over cyclonic anticyclonic qg vortices oml cooling of 1 c occurs over anticyclones because of the combined effects of downwelling instantaneous turbulent entrainment over the deep warm water column weak stratification and vertical dispersion of near inertial energy by contrast oml cooling of 4 c occurs over cyclones due to the combined effects of upwelling instantaneous turbulent entrainment over regions of tight vertical thermal gradients strong stratificati

ordovician organic walled microphytoplankton acritarch distribution the global scenario abstract a number of palaeobiogeographical models for ordovician organic walled microphytoplankton acritarchs prasinophytes and related groups have been published during the past 30 years a modern synthesis of ordovician acritarch palaeobiogeography based on previously published acritarch provinces and global distribution models as well as new plots on recently compiled palaeogeographical maps is presented review of the literature and new plots indicate that a number of preliminary conclusions can be drawn following minor biogeographical differentiation of acritarch assemblages during the cambrian provincialism started at the cambrian ordovician boundary in the late tremadocian a warm water assemblage containing the genera aryballomorpha athabascaella and lua but no diacrodians seems to be limited to low latitude localities such as laurentia and north china from the late tremadocian and throughout most of the arenig a peri gondwana acritarch assemblage with the easily recognisable taxa arbusculidium filamentosum coryphidium and striatotheca is present on the southern margin of gondwana and its distribution corresponds almost exactly with that of the calymenacean dalmanitacean trilobite fauna it seems reasonable to consider the acritarchs of baltica as belonging to a temperate water province which was probably not restricted to the palaeocontinent of baltica but had a wider distribution at about the same latitude as some of the elements recorded from baltica also occur in south china and argentina the maximum separation of the continents during the arenigian reflected by a pronounced biogeographical differentiation of most ordovician fossil groups led to the development of geographically distinct acritarch assemblages data from the late middle ordovician and the late ordovician remain too poor to elucidate global palaeobiogeographical patterns the biogeographical distribution of ordovician acritarchs appears similar to that of the resting cysts of modern dinoflagellates primarily controlled by latitude but also following the continental margins

rings in the ocean certain robust long lived eddy features in t he world s ocean have come to be k nown as rings the nomenclature stems from fuglister 1 1972 who c oined t he name based on the c ircle or ring of gulf stream waters t hat surrounded a class of eddies formed from t he g ulf stream through the pinch off of meanders here it s uffices to define rings as intense eddies or vortices that represent a wrapped up piece of a major ocean c urrent they t ranslate over space scales of hundreds to thousands of k ilometers and exist for periods lasting from months to years rings move t hrough the ocean carrying anomalies s imilar to the contrasts in physical biological and chemical properties observed across the major ocean c urrents while the term ring is t ied to fuglister t he existence ofthese features was evident at least as early as t he 1930s when iselin 2 1936 1940 encountered strong cold anomalies in the region south of the gulf stream that we would identify as c old corc cyclonic rings today iselin fully rec ognized these features as part of the highly time dependent eddy motion in the ocean later iselin fuglister 1948 were the first to survey what is now k nown as a warm core anticyc lonic ring there are tw o types of rings cold core rings are made up of w aters from the poleward s ide of c urrents like the gulf stream that are introduced to

global observations of large oceanic eddies 1 ten years of sea surface height ssh fields constructed from the merged topex poseidon t p and ers 1 2 altimeter datasets are analyzed to investigate mesoscale variability in the global ocean the higher resolution of the merged dataset reveals that more than 50 of the variability over much of the world ocean is accounted for by eddies with amplitudes of 5 25 cm and diameters of 100 200 km these eddies propagate nearly due west at approximately the phase speed of nondispersive baroclinic rossby waves with preferences for slight poleward and equatorward deflection of cyclonic and anticyclonic eddies respectively the vast majority of the eddies are found to be nonlinear

the coalescence of two east australian current warm core eddies two warm core eddies coalesced in about 20 days as their centers rotated around a point on the contracting line that joined them in the process of forming the new eddy the subsurface isothermal isohaline signature layer of one eddy was uplifted and somewhat depleted while that of the other was depressed

evolution and modulation of a poleward propagating anticyclonic eddy along the japan and kuril kamchatka trenches to investigate the relationships between the movement of an eddy and its interior structure and water properties four profiling floats were deployed in an anticyclonic eddy in the western north pacific in 2013 april october daily float profiles showed rapid changes in temperature and salinity corresponding to strong interactions between eddies north of the subtropical kuroshio extension after the first interaction with a warm core eddy in april the isolation of the winter mixed layer from the surface was observed forming a subsurface remnant layer another interaction with a cold fresh eddy at middepths in may resulted in the formation of a multilayer structure the eddy then moved poleward along the japan and kuril kamchatka trenches indicating changes in its propagation pattern coupled to its interior structure the eddy then moved northward june july stalled july august and moved eastward august october in addition to a general declining trend the properties of the warm saline core changed over a short time period coinciding with changes in propagation a density anomaly at middepths of the eddy changed location during the stalled period however denser waters were continuously observed in the southeast part of the eddy during its northward and eastward movement this unidirectional density anomaly pattern was consistent with the structure of the poleward propagating eddy which interacted with the western topographic boundary meridional exchanges of heat and material were potentially elevated by the eddy s advection and movement as well as by water modifications in the eddy associated with exchanges along its perimeter

anticyclonic eddies in the alaskan stream abstract anticyclonic eddies propagating southwestward in the alaskan stream as were investigated through analysis of altimetry data from satellite observations during 1992 2006 and hydrographic data from profiling float observations during 2001 06 fifteen long lived eddies were identified and categorized based on their area of first appearance three eddies were present at the beginning of the satellite observations another three formed in the eastern gulf of alaska off sitka alaska and four were first detected at the head of the gulf of alaska near yakutat alaska the other five eddies formed along the as between 157 and 169 w and were named as eddies while the eddies that formed in the gulf of alaska mainly decayed before exiting the gulf of alaska the as eddies mostly crossed the 180 meridian and reached the western subarctic gyre four of five as eddies formed under negative or weakly positive wind stress curls which possibly caused as separation from the coast comparison of eddy propag

the age and correlation of skiddaw group early ordovician sediments in the cross fell inlier northern england the skiddaw group in the cross fell inlier comprises the catterpallot formation of latest tremadoc or earliest arenig age the murton formation of arenig age and the kirkland formation of early llanvirn age each of these formations can be correlated with formations in the skiddaw group of the lake district the faulted contact of the catterpallot and kirkland formations is the probable extension of the causey pike fault cpf which separates two distinct sequences in the skiddaw inlier of the northern lake district contrasts across the cpf in the cross fell inlier reflect those seen in the skiddaw inlier the cpf is a major basement structure separating markedly different successions in the ordovician strata of northern england

eddy transport of heat and thermocline waters in the north pacific a key to interannual decadal climate variability abstract high resolution xbt transects in the north pacific ocean at an average latitude of 22 n are analyzed together with topex poseidon altimetric data to determine the structure and transport characteristics of the mesoscale eddy field based on anomalies in dynamic height 410 eddies are identified in 30 transects from 1991 to 1999 including eddies seen in multiple transects over a year or longer their wavelength is typically 500 km with peak to trough temperature difference of 2 2 c in the center of the thermocline the features slant westward with decreasing depth by 0 8 of longitude on average from 400 m up to the sea surface this tilt produces a depth varying velocity temperature correlation and hence a vertical meridional overturning circulation in the mean 3 9 sv sv 106 m3 s 1 of thermocline waters are carried southward by the eddy field over the width of the basin balanced mainly by northward flow in the surface layer corresponding northward heat transport is 0 086 0 012 pw

loop current mixed layer energy response to hurricane lili 2002 part ii idealized numerical simulations abstractin this second part of a two part study details of the upper ocean response within an idealized baroclinic current to a translating tropical cyclone are examined in a series of nonlinear reduced gravity numerical simulations based on observations obtained as part of a joint noaa national science foundation nsf experiment in hurricane lili 2002 the preexisting ocean mass and momentum fields are initialized with a gulf of mexico loop current like jet which is subsequently forced by a vortex whose wind stress field approximates that observed in the lili experiments because of 1 favorable coupling between the wind stress and preexisting current vectors and 2 wind driven currents flowing across the large horizontal pressure gradient wind energy transfer to the mixed layer can be more efficient in such a regime as compared to the case of an initially horizontally homogeneous ocean however nearly all energy is removed by advection and wave flux by two local inertial periods after storm pa

transient modulation of kuroshio upper layer flow by directly impinging typhoon morakot in east of taiwan in 2009 this study deals with the modulation of the kuroshio upper layer flow kulf in response to the passage of typhoon morakot in 2009 using regional oceanic modeling system roms and in situ measurements from argos drifters and argo floats the analysis of the simulated current fields near the typhoon track revealed an intermittency phenomenon of the kulf which was almost shut down for at least 6 hours the process begun 2 days prior to the approach of typhoon center due to blockage of the kulf by the steadily northerly winds and lasted for more than 2 days simultaneously shifting the kuroshio main stream kms path when the morakot gradually moved closely to the kuroshio the kms shifted vertically from the surface layer to deeper layer of 50 100 m depth and the maximum current speed in the kms decreased from more than 1 3 m s 1 to less than 1 1 m s 1 when the morakot center approached about 100 km to the original position of the kuroshio the kulf spread eastward for 1 5 degrees at 24 n when the morakot center moved to the original position of the kms the kuroshio abruptly rushed with a maximum speed near 1 4 m s 1 meanwhile an offshore cool jet originating from southeastern tip of taiwan was generated and extended northward along the kuroshio in the cool jet the lowest temperature reached about 5 c lower than the ambient waters modeled current variations and the cool jet during the morakot passage were validated by in situ measurements

interactions between hurricane catarina 2004 and warm core rings in the south atlantic ocean 1 the unexpected evolution of the first recorded south atlantic hurricane catarina over waters with homogeneous sea surface temperatures sst of 24 c in march 2004 was a challenge to the weather forecast community this work concentrates on a thorough data driven comparative analysis to make reliable diagnostics of the role of the ocean in the genesis and evolution of catarina we used several high resolution multisatellite derived products including three microwave based sst data sets multisatellite collinear data of sea surface height ssh anomalies significant wave heights and wind speeds four quikscat ocean surface wind vector products including the 12 5 km resolution swath data daily fields of absolute objectively analyzed ssh and corresponding geostrophic currents and argo floats the synergic use of these data sets showed that catarina interacted strongly with four warm core rings wcrs forcing upwelling of isotherms and mixed layer waters these interactions minimized the known negative sst feedback as attested by the sst differences being less than 1 2 c although the sst in the region was around 24 c below the palmen threshold the surface air temperatures were 14 c which still furnished a large air sea temperature gradient capable of extracting large enthalpy fluxes from the wcrs influenced by ekman pumping it is shown here that catarina achieved category 1 over the ocean on 26 march with its maximum intensity of 34 m s seen in the 12 5 km swath winds