geothermal structure of the miura boso plate subduction margin central japan abstract we have constrained the geothermal structure of the miura boso plate subduction margin located in central japan using maximum paleo temperature data derived from vitrinite reflectance measurements we established that higher maximum paleo temperatures are restricted to the western part of the early miocene hota accretionary complex hota and hayama groups indicating a spatial difference in the amount of slip upon the out of sequence thrust potentially associated with the izu bonin island arc collision the weakly deformed sedimentary sequences overlying the highly deformed hota group strata have much lower vitrinite reflectance values than the latter this variation indicates that the sedimentary sequences of the trench slope experienced a markedly lower maximum burial depth than the relatively deep buried and uplifted hota accretionary complex conversely maximum paleo temperatures obtained for tectonic blocks hosted by the neighboring mineoka ophiolite complex are very high ca 140 c for the large early miocene haccho formation blocks and 65 90 c for the other blocks this result suggests that the individual tectonic blocks enclosed in the ophiolite complex were subjected exhumation from depths of 3 5 km

surface climate variations over the north atlantic ocean during winter 1900 1989 abstract the low frequency variability of the surface climate over the north atlantic during winter is described using 90 years of weather observations from the comprehensive ocean atmosphere data set results are based on empirical orthogonal function analysis of four components of the climate system sea surface temperature sst air temperature wind and sea level pressure an important mode of variability of the wintertime surface climate over the north atlantic during this century is characterized by a dipole pattern in ssts and surface air temperatures with anomalies of one sign cast of newfoundland and anomalies of the opposite polarity off the southeast coast of the united states wind fluctuations occur locally over the regions of large surface temperature anomalies with stronger than normal winds overlying cooler than normal ssts this mode exhibits variability on quasi decadal and biennial time scales the decadal fluctuations are irregular in length averaging 9 years before 1945 and 1

marine incursions of the past 1500 years and evidence of tsunamis at suijin numa a coastal lake facing the japan trench sandy deposits of marine origin underlie the floor of suijin numa a coastal lake midway along the subduction zone marked by the japan trench the deposits form three units that are interbedded with lacustrine peat and mud above a foundation of marine probably littoral sand unlike the lacustrine deposits all three sandy units contain marine and brackish diatoms the middle unit b contains in addition graded beds sug gestive of multiple waves of long wavelength and period the uppermost unit c probably dates to a time in the area s written history when the lake was separated from the sea by a beach ridge plain at least 0 5 km wide and several metres high units a and b postdate ad 540 870 and unit c postdates ad 1030 1640 as judged from radiocarbon dating of leaves and seeds unit b pre dates ad 915 and unit c postdates that year as judged from a tephra within the peat that separates units b and c the age constraints permit correlation of unit b with a tsunami in ad 869 that reportedly devastated at least 100 km of coast approximately centred on sendai unit c may represent a later catastrophic tsunami in 1611 or perhaps a storm surge that inundated much of sendai the lake lacks obvious signs of tsunamis from the region s largest twentieth century earthquakes which were centred to the north in 1933 m 8 1 and directly offshore in 1936 m 7 5 and 1978 mw 7 6

geodetic imaging of plate motions slip rates and partitioning of deformation in japan 1 interseismic deformation in japan results from the combined effects of tectonic processes including rotation of crustal blocks and the earthquake cycle process of elastic strain accumulation about upper plate faults and subduction zone interfaces we use spherical linear block theory constrained by geodetic observations from densely spaced global positioning system gps stations to estimate plate motions fault slip rates and spatially variable interplate coupling on the japan kuril sagami and nankai subduction zones the reference model developed in this paper consists of 20 blocks produces a mean residual velocity magnitude of 1 84 mm yr at 950 stations and accounts for 96 of the observed interseismic deformation signal we estimate fault slip rates in excess of 15 mm yr along the niigata kobe tectonic zone and itoigawa shizuoka tectonic line through central japan confirming their hypothesized roles as major tectonic boundaries oblique convergence across the nankai trough is partitioned with 3 4 of the 30 mm yr of trench parallel motion accommodated by strike slip motion on the subduction interface and the remaining 1 4 accommodated by right lateral slip on the median tectonic line in contrast our models suggest negligible slip partitioning in eastern hokkaido where oblique slip on the japan kuril subduction interface accommodates all of the trench parallel component of relative plate motion inferred spatial variations in the rake and magnitude of slip deficit on subduction zone interfaces reflect the influences of megathrust geometry and earthquake cycle processes such as enhanced elastic strain accumulation about seismic asperities and coseismic sense fault motion indicative of silent slip events or afterslip following large earthquakes

a comparison of several methods for the determination of iron hydroxides and associated orthophosphates in estuarine particulate matter abstract five different methods commonly used for the extraction and the determination of iron hydroxides and or the associated phosphorus held in marine seston or in sediments have been tested on single phase minerals goethite and apatite on reference minerals so1 and so2 and on suspended matter samples from the st lawrence estuary and from the estuary of the eastmain river a major james bay affluent in northern quebec canada the citrate dithionite bicarbonate cdb procedure generally seemed to be more reproducible and more specific the validity of the other methods respectively using as extracting reagents ammonium oxalate oxalic acid hydroxylamine hydrochloride calcium nitrilotriacetic acid and acetate tartrate is discussed the cdb extraction is included in an analytical scheme which allows to distinguish between three fractions of phosphorus this chemical speciation is applied to the study of p retention on fe hydroxides and to its potential desorption

the phosphorus cycle in coastal marine sediments the concentration of dissolved phosphate in sediment box cores from the laurentian trough in the gulf of st lawrence increased sharply across the sediment water interface from 2 0 mol po4 1 in the bottom water to 6 3 mot po4 1 in the top cm remained almost constant at this value down to 5 15 cm depth and then increased rapidly with further depth in the region of constant concentration phosphate is buffered by sorption equilibria with the sediment the production rate of phosphate the sorption capacity of the sediment and the thickness of the diffusive boundary layer at the sediment water interface appear to control the shape of the pore water profile even though the buffering places an upper limit on the concentration gradient across the sediment water interface and hence on the flux the phosphate flux to the overlying water is controlled by the production rate of phosphate within the sediment a model is proposed to relate sediment chemistry to phosphorus fluxes

tropical extratropical connection in the atlantic atmosphere ocean variability a question how sea surface temperature sst fluctuations in the tropical atlantic affect the north atlantic atmosphere ocean system is addressed using an atmospheric general circulation model coupled to a 50 m deep slab ocean mgcm and a linear baroclinic model a comparison of a 60 yr integration in which the tropical ssts are prescribed to observations toga ml with the control mgcm run shows that the tropical sst variations selectively enhance variance of the north atlantic oscillation nao by about 80 this is partly due to extratropical height anomalies associated with two dominant modes monopole and dipole of tropical atlantic sst variability because they both have a projection on to the nao in the toga ml run the simulated midlatitude height anomalies accompany characteristic sst anomaly patterns beneath and they are consistent with observations analyses of steady linear responses to the heating in the tropical atlantic and transient eddy feedback in midlatitude reveal that the substantial part of height anomalies is generated by the latter rather than the former the anomalous eddy forcing is however organized not only by the heating in the tropical atlantic but also by the tropical pacific sst variations through the teleconnection over north america it is suggested that the tropical atlantic sst variability does affect the north atlantic atmosphere and ocean but the dynamical connection is tenuous in comparison with the pacific

chemodynamics of trace metal fractions in surface sediments of the pandoh lake lesser himalaya india the seasonal variation in the trace metals concentrations cd co cu fe mn ni pb and zn were investigated in surface sediments of the pandoh lake the horizontal distribution of tc tn and tp reflects spatial and temporal differences in sedimentary organic production the chemical sequential extraction of heavy metals was carried out by seven step fractionation scheme leleyter and probst in int j environ chem 73 109 128 1999 the significant concentrations of ni and cd were associated with water soluble eua fraction in the monsoon and winter respectively while exchangeable exch and carbonate bound carb fractions for ni and cd were abundant in winter and summer the cd cu and pb associated with exch fraction in the summer season support their availability on exchange sites due to oxidized nature of surface sediments enrichment of co fe mn and zn in afeo fraction showed poor bioavailability while cd cu and mn in the monsoon co in the winter and summer and zn in the winter season showed significant organically bound org fraction the anova was significant for chemical fractions of trace elements except carb fraction of pb and zn and cfeo fraction of pb factor analysis revealed that the eua exch and carb fractions together control the metal enrichment of mno afeo and cfeo fractions in the summer season

the state of stress in the earth s crust along the northwestern flank of the pacific seismic focal zone before the tohoku earthquake of 11 march 2011 abstract this paper presents a detailed reconstruction of the state of stress in the earth s crust in the japanese seismic focal zone before the tohoku earthquake of march 11 2011 the stress parameters are determined using the method of cataclastic analysis mca of discontinuous displacements this method integrates some of the main principles of the theory of plastic deformation and a generalization of the results of rock failure experiments the reconstruction of the state of stress is based on earthquake focal mechanism data for two magnitude ranges mw 1 3 0 5 5 and 2 5 0 7 0 the calculations for the first data set are performed at six depths stress reconstruction for the second data set is performed from 0 to 50 km the focal mechanism data provides reasonably stable parameters of the stress field for magnitudes in this range a large amount of data on the focal mechanisms of earthquakes with magnitudes between 3 0 and 5 5 has allowed us to obtain new data on changes in the stress field which were missed in the previous calculation for the second data set it is shown that in the upper part of the lithosphere up to 90 km the axis of maximum compression is generally oriented slightly 25 35 under the oceanic plate west of the japan trench and it dips subvertically east of the trench the upper part of the tectonosphere is divided into two geodynamic regimes subhorizontal compression west of the trench axis and subhorizontal extension east of the trench axis west of the japan trench the axis of maximum horizontal compression shmax is orthogonal to the trench axis but east of the japan trench its orientation has changed 90 the underthrusting shear stress that acts normal to the horizontal planes has a similar west and west southwest direction in the upper layers 0 50 km deviations in the orientation are observed at depths between 70 and 90 km at the junction between the japan trench and the nankai trough and in the crust of the northeastern part of the tohoku region obtained results are summarized in 2 d pattern which can be used to explain the loading mechanism in the region of the tohoku earthquake the results of the stress reconstruction also allowed us to obtain the new specific features of the field stress the oceanic trench divides lithosphere into the areas of high effective pressure west of the trench axis and the areas of low effective pressure east of the trench axis the rupture developed in the area of the maximum stress gradient and it stopped in the north east and the south west directions where there were areas of high effective pressure

teleconnections in the geopotential height field during the northern hemisphere winter abstract contemporaneous correlations between geopotential heights on a given pressure surface at widely separated points on earth referred to as teleconnections in this paper are studied in an attempt to identify and document recurrent spatial patterns which might be indicative of standing oscillations in the planetary waves during the northern hemisphere winter with time scales on the order of a month or longer a review of existing literature on the subject reveals the existence of at least four such patterns the north atlantic and north pacific oscillations identified by walker and bliss 1932 a zonally symmetric seesaw between sea level pressures in polar and temperature latitudes first noted by lorenz 1951 and what we will refer to as the pacific north american pattern which has been known to operational long range forecasters in this country since the 1950 s a data set consisting of nmc monthly mean sea level pressure and 500 mb height analyses for a 15 year period is used as a basis fo

shallow dynamic overshoot and energetic deep rupture in the 2011 mw 9 0 tohoku oki earthquake strong spatial variation of rupture characteristics in the moment magnitude mw 9 0 tohoku oki megathrust earthquake controlled both the strength of shaking and the size of the tsunami that followed finite source imaging reveals that the rupture consisted of a small initial phase deep rupture for up to 40 seconds extensive shallow rupture at 60 to 70 seconds and continuing deep rupture lasting more than 100 seconds a combination of a shallow dipping fault and a compliant hanging wall may have enabled large shallow slip near the trench normal faulting aftershocks in the area of high slip suggest dynamic overshoot on the fault despite prodigious total slip shallower parts of the rupture weakly radiated at high frequencies whereas deeper parts of the rupture radiated strongly at high frequencies

relationships between atmospheric internal variability and the responses to an extratropical sst anomaly abstract the january and february responses of a gcm to an imposed extratropical pacific sst anomaly are compared with the patterns of the model s internal variability relevant patterns of internal variability are diagnosed from ensembles of model control runs by regressing monthly mean geopotentials and temperatures against low level temperatures in the vicinity of the sst anomaly and by eof analysis these patterns are found to play a significant role in determining the local and the remote responses to the sst anomaly different responses to the sst anomaly in the gcm s january and february climates are largely explained by the differences in the regression patterns and in the leading eof the gcm response may be considered as comprising a direct linear response to low level heating that is local to the forcing and baroclinic and an eddy forced component that closely resembles patterns of the model s internal variability it is equivalent barotropic and extends over the entire hemisphere the results

the modeled atmospheric response to midlatitude sst anomalies and its dependence on background circulation states abstract the atmospheric response to a midlatitude sst anomaly in the north pacific and its dependence on background flow are examined in a gcm experiments are conducted using the same warm sst anomalies but two different model states perpetual january and perpetual february the atmospheric responses to the sst anomalies are statistically significant in both january and february but are completely different the anomalous circulation in january is characterized by a trough decaying with height immediately downstream of the sst anomalies in february the anomalous circulation is dominated by a downstream ridge growing with height the patterns of the anomalous heights in the two months are nearly orthogonal vorticity and thermodynamic budgets are diagnosed to illustrate how the anomalous circulations are maintained over the sst anomalies low level convergence and ascent are observed in both months in january the anomalous convergence is balanced by a residual due primarily to the forcing by submont

crustal stress field perturbations in the continental margin around the korean peninsula and japanese islands abstract seismic activity and focal mechanisms are governed by the effective stress field that is a combined result of regional tectonic processes and local stress perturbation this study investigates the regional variation in the stress field in the eastern continental margin of the eurasian plate around the korean peninsula and japanese islands using a damped stress inversion technique based on the focal mechanism solutions of regional earthquakes the dominant compressional stress is directed ene wsw around the korean peninsula and eastern china e w at the central east sea and northern and southern japan nw se at central japan and n s around the northern nankai trough the dominant compression direction changes rapidly in the east sea and japanese islands which may be due to the combined effects of tectonic loading in the subduction zones off the japanese islands and the india eurasia plate boundary the crustal stress fields around the subduction zones off the japanese islands present characteristic depth dependent orientations the orientations of the largest horizontal stress components h in the subduction zones are subparallel with the plate convergence directions at shallow depths the h orientations are observed to rotate clockwise with the depth owing to slab subduction and lithospheric deformation the regional stress field around the japanese islands was perturbed temporally by the 2011 m9 0 tohoku oki megathrust earthquake the regional stress field was recovered in a couple of years the stress field and tectonic structures are mutually affected causing stress field distortion and a localized mixture of earthquakes in different faulting types

phosphorus speciation and availability in intertidal sediments of the yangtze estuary china abstract in order to better understand p cycling and bioavailability in the intertidal system of the yangtze estuary both surface 0 5 cm and core 30 cm long sediments were collected and sequentially extracted to analyze the solid phase reservoirs of sedimentary p loosely sorbed p fe bound p authigenic p detrital p and organic p the total sedimentary p in surface and core sediments ranged from 14 58 36 81 mol g 1 and 17 11 24 55 mol g 1 respectively and was dominated by inorganic p the average percentage of each fraction of p in surface sediments followed the sequence detrital p 54 9 fe bound p 23 7 organic p 14 3 authigenic p 6 3 loosely sorbed p 0 8 whereas in core sediments it followed the sequence detrital p 61 7 fe bound p 17 0 authigenic p 13 1 organic p 7 5 loosely sorbed p 0 7 post depositional reorganization of p was observed in both surface and core sediments converting organic p and fe bound p to authigenic p the accumulation rates and burial efficiencies of the total p in the intertidal area ranged from 118 70 904 98 mol cm 2 a 1 and 80 29 88 11 respectively high burial efficiency of the total p is likely related to the high percentage of detrital p and the high sediment accumulation rate in addition the bioavailable p represented a significant proportion of the sedimentary p pool which on average accounted for 37 4 and 25 1 of the total p in surface and core sediments respectively this result indicates that the tidal sediment is a potential internal source of p for this p limiting estuarine ecosystem

are peak summer sultry heat wave days over the yangtze huaihe river basin predictable abstractyangtze huaihe river basin yhrb is the core region of sultry heat wave occurrence over china during peak summer july and august ja the extremely hot and muggy weather is locally controlled by a descending high pressure anomaly connected to the western pacific subtropical high during 1961 2015 the heat wave days hwds in ja over the yhrb exhibits large year to year and decadal variations prediction of the total number of hwds in ja is of great societal and scientific importance the summer hwds is preceded by a zonal dipole sst tendency pattern in the tropical pacific and a meridional tripole sst anomaly pattern over north atlantic the former signifies a rapid transition from a decaying central pacific el nino in early spring to a developing eastern pacific la nina in summer which enhances the western pacific subtropical high and increases pressure over the yhrb by altering the walker circulation the north atlantic tripole sst anomalies persist from the preceding winter to ja and excit

the general circulation model response to a north pacific sst anomaly dependence on time scale and pattern polarity abstract a general circulation model was integrated with perpetual january conditions and prescribed sea surface temperature sst anomalies in the north pacific a characteristic pattern with a warm region centered northeast of hawaii and a cold region along the western seaboard of north america was alternately added to and subtracted from the climatological sst field long 1350 day runs as well as short 180 day runs each starting from different initial conditions were performed the results were compared to a control integration with climatological ssts the model s quasi stationary response does not exhibit a simple linear relationship with the polarity of the prescribed sst anomaly in the short runs with a negative sst anomaly over the central ocean a large negative height anomaly with an equivalent barotropic vertical structure occurs over the gulf of alaska for the same sst forcing the long run yields a different response pattern in which an anomalous high prevails over northern canada and

atmosphere ocean thermal coupling in the north atlantic a positive feedback in this article it is examined whether a positive atmosphere ocean feedback is found over the north atlantic through a series of general circulation model gcm experiments a 60 year integration of an atmospheric gcm agcm coupled with a 50 m deep motionless ocean was conducted the coupled run was compared with two uncoupled runs one with prescribed mid latitude climato logical sea surface temperatures ssts and the other with daily ssts derived from the coupled experiment the uncoupled atmosphere forces the slab ocean to obtain sst responses in these runs consistent with previous studies the coupled atmosphere ocean fields show interannual variances larger than those in the uncoupled runs due to reduction in the local thermal damping patterns of maximum atmosphere ocean covariability show the north atlantic oscillation nao and tripole sst anomalies both in the coupled and uncoupled fields indicating a dominant role of the atmosphere in generating the sst anomalies on the other hand analyses of the temporal variability in the three runs suggest an active role of sst anomalies in determining the polarity of the air sea coupled variability longer than the interannual time scale a combined analysis of forcing sst upper air height and the response sst anomalies in the uncoupled run identified that a patch of positive sst anomalies in the mid latitude band around 40 n effectively excite the positive phase of the nao which in turn reinforces the tripole sst anomalies this relationship was further confirmed by a nine member ensemble agcm experiment forced by the relevant sst anomalies since the forcing and response sst anomaly patterns bear some resemblance these results manifest positive feedback at work in the coupled atmosphere ocean patterns the processes responsible for this positive feedback were elaborated by a series of linear model experiments the local thermal adjustment of the atmosphere to the sst anomalies results in increased precipitation over the gulf stream region associated diabatic heating applied to a linear baroclinic model yields a positive height response to the east which highly influences the southern part of the nao this stationary response in turn induces a northward deflection in the storm track activity leading to an eddy vorticity feedback that tends to force the positive phase of the nao

the influence of atlantic sea surface temperature anomalies on the north atlantic oscillation abstract the influence of atlantic sea surface temperature sst anomalies on the atmospheric circulation over the north atlantic sector during winter is investigated by performing experiments with an atmospheric general circulation model these consist of a 30 yr run with observed sst anomalies for the period 1961 90 confined geographically to the atlantic ocean and of a control run with climatological ssts prescribed globally a third 30 yr integration with observed ssts confined to the south atlantic is made to confirm present findings the simulated interannual variance of 500 hpa wintertime geopotential heights over the north atlantic attains much more realistic values when observed atlantic ssts are prescribed circulation patterns that resemble the positive phase of the north atlantic oscillation nao become more pronounced in terms of the leading eof of winter means and a cluster analysis of daily fields the variance of an interannual nao index increases by fivefold over its control value atl

synoptic eddy feedback and air sea interaction in the north atlantic region this paper explores the role of synoptic eddy feedback in the air sea interaction in the north atlantic region particularly the interaction between the north atlantic oscillation nao and the north atlantic sea surface temperature anomalies ssta tripole a linearized five layer primitive equation atmospheric model with synoptic eddy and low frequency flow self interaction is coupled with a linearized oceanic mixed layer model to investigate this issue in this model the climatological storm track activity or synoptic eddy activity is characterized in terms of spatial structures variances decay time scales and propagation speeds through the complex empirical orthogonal function ceof analysis on the observed data which provides a unique tool to investigate the role of synoptic eddy feedback in the north atlantic air sea coupling model experiments show that the nao like atmospheric circulation anomalies can produce tripole like ssta in the north atlantic ocean and the tripole like ssta can excite a nao like dipole with an equivalent barotropic structure in the atmospheric circulation which suggests a positive feedback between the nao and the ssta tripole this positive feedback makes the nao ssta tripole like mode be the leading mode of the coupled dynamical system the synoptic eddy feedback plays an essential role in the origin of the nao ssta tripole like leading mode and the equivalent barotropic structure in the atmosphere without synoptic eddy feedback the atmosphere has a baroclinic structure in the response field to the tripole like ssta forcing and the leading mode of the dynamic system does not resemble nao ssta tripole pattern

impact of megathrust geometry on inversion of coseismic slip from geodetic data application to the 1960 chile earthquake 1 we analyze the role of megathrust geometry on slip estimation using the 1960 chile earthquake mw 9 5 as an example a variable slip distribution for this earthquake has been derived by barrientos and ward 1990 applying an elastic dislocation model with a planar fault geometry their model shows slip patches at 80 110 km depth isolated from the seismogenic zone interpreted as aseismic slip we invert the same geodetic data set using a finite element model fem with precise geometry derived from geophysical data isoparametric fem is implemented to constrain the slip distribution of curve shaped elements slip resolved by our precise geometry model is limited to the shallow region of the plate interface suggesting that the deep patches of moment were most likely an artifact of the planar geometry our study emphasizes the importance of fault geometry on slip estimation of large earthquakes

a rotated eigenanalysis of the correlation between 700 mb heights and sea surface temperatures in the pacific and atlantic abstract associations between pacific and atlantic sea surface temperature sst and the 700 mb circulation were studied using 30 years 1949 78 of gridded monthly data the monthly data were grouped into four nonstandard seasons for the analysis the linear correlation between the two fields sst and 700 mb heights was analyzed by finding the eigenvalue solution of the mean product matrix of the cross correlations this technique introduced by prohaska was modified through the use of a varimax rotation the result is a set of pairs of patterns one pattern for each medium which explains part of the linear correlation between the two fields the number of significant modes pairs was determined by a monte carlo simulation one well known atmospheric teleconnections pattern referred to as the pacific north american pna pattern by wallace and gutzler was found in all seasons however seasonal differences were noted during the warm season the pna pattern manifests itself as the great plains g

mechanisms determining the atmospheric response to midlatitude sst anomalies abstract previous gcm experiments demonstrated that a model atmosphere produces two different responses to a midlatitude warm sst anomaly over the pacific under perpetual january and february conditions to elucidate the mechanisms responsible for the different gcm responses and their dependence on the background flow experiments with two idealized models are conducted experiments with a linear baroclinic model reveal that the gcm responses at equilibrium are primarily maintained by the anomalous eddy forcing the anomalous flow induced directly by an idealized initial heat source exhibits little sensitivity to the background flow eddy feedbacks on the heating induced anomalous flow are examined using a linear storm track model the anomalous eddy forcing produced by the storm track model is sensitive to the basic state the eddy forcing in january acts to shift the heating induced upper level ridge toward the northeast of the gulf of alaska while in february it acts to reinforce the ridge this sugge

observed positive feedback between the nao and the north atlantic ssta tripole 1 ncep ncar reanalysis data from 1948 to 2001 are used to examine the relationship between the north atlantic oscillation nao and the north atlantic sea surface temperature anomaly ssta tripole it is demonstrated that the atmospheric anomalies associated with nao produce tripole like sea surface temperature sst anomalies in turn the ssta tripole produces nao like atmospheric anomalies therefore a positive feedback between the nao and the ssta tripole is suggested the results are statistically significant they clarify prior uncertainties associated with the relationship between the nao and the north atlantic ssta tripole

observed impact of atlantic sst anomalies on the north atlantic oscillation the large scale patterns of covariability between monthly sea surface temperature sst and 500 mb height anomalies z500 in the atlantic sector are investigated as a function of time lag in the ncep ncar reanalysis 1958 97 in agreement with previous studies the dominant signal is the atmospheric forcing of sst anomalies but statistically significant covariances are also found when sst leads z500 by several months in winter a panatlantic sst pattern precedes the north atlantic oscillation nao by up to 6 months such long lead time covariance is interpreted in the framework of the stochastic climate model reflecting the forcing of the nao by persistent atlantic sst anomalies a separate analysis of midlatitudes 208 708n and tropical 208s 208n sst anomalies reveals that the bulk of the nao signal comes from the midlatitudes a dipolar anomaly with warm sst southeast of newfoundland and cold sst to the northeast and southeast precedes a positive phase of the nao and it should provide a prediction of up to 15 of its monthly variance several months in advance since the forcing sst pattern projects significantly onto the tripole pattern generated by the nao these results indicate a positive feedback between the sst tripole and the nao with a strength of up to 25 mk 21 at 500 mb or 2 3 mb k21 at sea level additionally a warming of the tropical atlantic 208s 208n roughly symmetric about the equator induces a negative nao phase in early winter this tropical forcing of the nao is nearly uncorrelated with and weaker than that resulting from the midlatitudes and is associated with shorter lead times and reduced predictive skill

an individual particle analysis and budget study of onondaga lake sediments1 the sedimentation of particles in onondaga lake n y was examined by scanning electron microscopy with automated image analysis and x ray energy spectroscopy sax a technique of individual particle characterization the composition of the particles coming into the lake and those present in the sediments was analyzed to calculate an annual sediment budget an allochthonous sediment input of 21 800 tonnesmyr and a sediment output of 3 300 tonnesmyr i were calculated from flow rates sediment loads and concentrations a sediment mass budget yielded an autochthonous sediment formation of 15 900 tonneseyr l and a net sedimentation of 34 500 tonnessyr l calcite particles comprised a majority of these autochthonous sediments and were found in the epilimnion in addition measurable amounts of iron sulfide were formed in the hypolimnion such budgets provide information based on different particle classes for studies of particle formation transport and deposition processes in limnetic environments

the differences between early and midwinter atmospheric responses to sea surface temperature anomalies in the northwest atlantic abstract using an atmospheric global spectral model it is shown that the winter atmosphere in the midlatitudes is capable of reacting to prescribed sea surface temperature sst anomalies in the northwest atlantic with two very different responses the nature of the response is determined by the climatological conditions of the winter regime experiments are performed using either the perpetual november or january conditions with or without the prescribed sst anomalies warm sst anomalies in november result in a highly significant anomalous ridge downstream over the atlantic with a nearly equivalent barotropic structure in january the response is a statistically less significant trough the presence of the sst anomalies also causes a northward southward shift of the atlantic storm track in the november january cases a diagnostic analysis of the anomalous heat advection in the simulations reveals that in the january cases the surface heating is offset primarily by the strong horizontal cold advect

dynamics of synoptic eddy and low frequency flow interaction part iii baroclinic model results abstract in this three part study a linear closure has been developed for the synoptic eddy and low frequency flow self interaction and demonstrated that internal dynamics plays an important role in generating the leading low frequency modes in the extratropical circulation anomalies during cold seasons in part iii a new linearized primitive equation system is first derived for time mean flow anomalies the dynamical operator of the system includes a traditional part depending on the observed climatological mean state and an additional part from the self feedback closure utilizing the observed climatological properties of synoptic eddy activity the latter part relates nonlocally all the anomalous eddy forcing terms in equations of momentum temperature and surface pressure to the time mean flow anomalies using the observational data the closure was validated with reasonable success and it was found that terms of the self feedback in the momentum and pressure equations tend to reinforce the low f

phosphorus fractionation in surficial sediments of pandoh lake lesser himalaya himachal pradesh india abstract the fractionation of p in pandoh lake surface sediments has been investigated for the first time in order to understand its environmental availability and sources and the eutrophication status of this lake inorganic p is present mainly as authigenic p step iii the authigenic p concentration is higher in winter relative to the summer and monsoon seasons and ranged from 35 9 to 46 9 g g the loosely sorbed or exchangeable p step i fe iii bound p step ii and detrital inorganic p step iv were higher in the monsoon season and varied from 3 70 to 11 1 g g 16 9 to 32 0 g g and 9 89 to 17 0 g g respectively organic p reached a maximum in the summer season and ranged from 8 00 to 14 9 g g authigenic p and detrital inorganic p show seasonal changes as ph influences the interaction between p and caco 3 in the water column in the winter season phosphate is precipitated out of the water column and fixed in the sediments as a result of an increase in ph calcite bound p in the sediments may be redissolved by decreasing ph in the summer season relatively high rates of mineralization during the monsoon results in the seasonal pattern of organic p fractionation to sediment as follows monsoon winter

interplate seismogenic zones along the kuril japan trench inferred from gps data inversion stress accumulation between earthquakes results from slip that is insufficient to fully accommodate plate movement an inverse analysis of gps data from the kuril japan trench reveals a trench parallel belt of stress accumulation with six peaks in the depth range of 10 40 km suggesting potential source regions for future earthquakes in the subduction zones around japan where four plates interact with one another large earthquakes have occurred repeatedly1 these interplate earthquakes are part of the process of tectonic stress accumulation and release that is driven by relative plate motion2 3 4 stress accumulation between earthquakes results from slip deficit slip that is insufficient to fully accommodate plate movement for the prediction of large earthquakes it is therefore important to monitor the distribution of slip deficit on plate interfaces here we apply an inversion method based on bayesian modelling using direct and indirect prior information on the magnitude and distribution of fault slip5 to horizontal and vertical velocities from global positioning system data for the seismically calm period between 1996 and 2000 we obtain a precise distribution of slip deficit rates on the interface between the north american and pacific plates around japan which reveals a trench parallel belt of slip deficit with six peaks in the depth range of 10 40 km these peaks agree with the source regions of past large interplate earthquakes along the kuril japan trench we conclude that the slip deficit zones identified with our method are potential source regions of large earthquakes

distribution of stress state in the nankai subduction zone southwest japan and a comparison with japan trench to better understand the distribution of three dimensional stress states in the nankai subduction zone southwest japan we review various stress related investigations carried out in the first and second stage expeditions of the nankai trough seismogenic zone experiment nantroseize by the integrated ocean drilling program iodp and compile the stress data overall the maximum principal stress 1 in the shallower levels 1 km below seafloor or in underlying accretionary prism with 1 becoming horizontal is also suggested at all deeper drilling sites we also make a comparison of the stress state in the hanging wall of the frontal plate interface between site c0006 in the nankai and site c0019 in the japan trench subduction zone drilled after the 2011 mw 9 0 tohoku oki earthquake in the japan trench a comparison between stress state before and after the 2011 mega earthquake shows that the stress changed from compression before the earthquake to extension after the earthquake as a result of the comparison between the nankai trough and japan trench a similar current stress state with trench parallel extension was recognized at both c0006 and c0019 sites hypothetically this may indicate that in nankai trough it is still in an early stage of the interseismic cycle of a great earthquake which occurs on the decollement and propagates to the toe around site c0006

dynamics of synoptic eddy and low frequency flow interaction part ii a theory for low frequency modes abstract amidst stormy atmospheric circulation there are prominent recurrent patterns of variability in the planetary circulation such as the antarctic oscillation aao arctic oscillation ao or north atlantic oscillation nao and the pacific north america pna pattern the role of the synoptic eddy and low frequency flow self feedback in the formation of these dominant low frequency modes is investigated in this paper using the linear barotropic model with the self feedback proposed in part i it is found that the ao like and aao like leading singular modes of the linear dynamical system emerge from the stormy background flow as the result of a positive self feedback this self feedback also prefers a pna like singular vector as well among other modes under the climatological conditions of northern winters a model with idealized conditions of basic mean flow and activity of synoptic eddy flow and a prototype model are also used to illustrate that there is a natural scale selection for the aao

changes in extent of phosphorus release in a shallow lake lake groβer muggelsee germany berlin due to climatic factors and load abstract based upon biweekly investigations of interstitial and pelagial water parameters as well as sediment phosphorus p speciation the mechanisms important for the summer p release in eutrophic lake gro er muggelsee germany are described microbial processes were the driving force of mainly anaerobic and also aerobic p release from iron reductant soluble and organic p rich sediments for 1992 and 1993 two years of very different runoff characteristics the extent of p release was indirectly controlled by external factors including the supply of dissolved oxygen and nitrate via inflow high runoff changes in land use e g decreasing nitrogen fertilization and climatic factors and it was facilitated by wind induced rapid changes of stratification and mixing events

adsorption capacity of phosphorus in baltic sea sediments abstract nutrient budgets of the baltic sea indicate that an increased loading of phosphorus to a great extent is counteracted by adsorption to the sediments resulting in a comparatively small net increase of the phosphorus concentration in the water column the parmanent salinity stratification and increasing eutrophication of this sea has caused almost permanent anoxic conditions which limits the phosphorus storage capacities in the deep basins below the halocline the phosphorus loading has increased about eight fold during this century and does not show any sign of declination the questions then arise what type of sediments store the phosphorus what are the binding mechanisms and is the maximim storage capacity approached in an attempt to partly answer these questions the phosphorus adsorption capacities of three different baltic sea sediments have been investigated the greatest amount of adsorbed phosphorus measured as mol g 1 dry substance is found for an accumulation bottom from the deeper part of the baltic sea and the lowest for a transportation bottom above the halocline however if the rates are recalculated as phosphorus adsorption per area which is more pertinent from an ecological point of view i e most phosphorus is adsorbed in the shallow sediments a comparison of the experimental data and ambient conditions in the water and sediments indicate that adsorption of phosphate from the water column plays a minor role in the phosphorus budget of the baltic sea only the assimilation of phosphate and subsequent sedimentation and decomposition of organic matter at the sediment surface will result in a sufficiently high sediment pore water concentration to explain the large sink of phosphorus to the baltic sea sediments calculated from input and output data

left hand rule for synoptic eddy feedback on low frequency flow 1 in this study scale interaction between synoptic eddies and low frequency flow is investigated the synoptic eddy feedback is a key process in sustaining the low frequency flow we show clear evidence using ncep reanalysis data that there is a general underlying rule the left hand rule governing the synoptic eddy feedback onto low frequency flow this rule states that eddy vorticity fluxes are directed preferentially about 90 degrees toward their left hand side so that they converge into cyclonic flow and diverge from anticyclonic flow therefore the eddy vorticity flux plays a positive role in reinforcing low frequency flow citation kug j s and f f jin 2009 left hand rule for synoptic eddy feedback on low frequency flow geophys res lett 36 l05709 doi 10 1029 2008gl036435

interdecadal variability of the pacific ocean model response to observed heat flux and wind stress anomalies variability of the pacific ocean is examined in numerical simulations with an ocean general circulation model forced by observed anomalies of surface heat flux wind stress and turbulent kinetic energy tke over the period 1970 88 the model captures the 1976 77 winter time climate shift in sea surface temperature as well as its monthly seasonal and longer term variability as evidenced in regional time series and empirical orthogonal function analyses examination of the surface mixed layer heat budget reveals that the 1976 77 shift was caused by a unique concurrance of sustained heat flux input anomalies and very strong horizontal advection anomalies during a multi month period preceding the shift in both the central pacific region where cooling occurred and the california coastal region where warming occurred in the central pacific the warm conditions preceding and the cold conditions following the shift tend to be maintained by anomalous vertical mixing due to increases in the atmospheric momentum flux tke input into the mixed layer which deepens in the model after the shift from the early 1970s to the late 1970s and 1980s since the ocean model does not contain feedback to the atmosphere and it succeeds in capturing the major features of the 1976 77 shift it appears that the midlatitude part of the shift was driven by the atmosphere although effects of midlatitude ocean atmosphere feedback are still possible the surface mixed layer heat budget also reveals that in the central pacific the effects of heat flux input and vertical mixing anomalies are comparable in amplitude while horizontal advection anomalies are roughly half that size in the california coastal region in contrast where wind variability is much weaker than in the central pacific horizontal advection and vertical mixing effects on the mixed layer heat budget are only one quarter the size of typical heat flux input anomalies

dynamics of synoptic eddy and low frequency flow interaction part i a linear closure abstract the interaction between synoptic eddy and low frequency flow self has been recognized for decades to play an important role in the dynamics of the low frequency variability of the atmospheric circulation in this three part study a linear framework with a stochastic basic flow capturing both the climatological mean flow and climatological measures of the synoptic eddy flow is proposed based on this linear framework a set of linear dynamic equations is derived for the ensemble mean eddy forcing that is generated by anomalous time mean flows by assuming that such dynamically determined eddy forcing anomalies approximately represent the time mean anomalies of the synoptic eddy forcing and by using a quasi equilibrium approximation an analytical nonlocal dynamical closure is obtained for the two way self feedback this linear closure directly relating time mean anomalies of the synoptic eddy forcing to the anomalous time mean flow becomes an internal part of a new linear dynamic system for an

displacement above the hypocenter of the 2011 tohoku oki earthquake the moment magnitude m w 9 0 2011 tohoku oki mega thrust earthquake occurred off the coast of northeastern japan combining global positioning system gps and acoustic data we detected very large sea floor movements associated with this event directly above the focal region an area with more than 20 meters of horizontal displacement that is four times larger than those detected on land stretches several tens of kilometers long along the trench the largest amount reaches about 24 meters toward east southeast just above the hypocenter furthermore nearly 3 meters of vertical uplift occurred contrary to observed terrestrial subsidence

a pan atlantic decadal climate oscillation sea surface temperature sst variabilities on time scales of 10 14 years have been documented in various parts of the atlantic ocean here we present observational evidence that these regional variabilities are part of a coherent pan atlantic decadal oscillation pado characterized by zonal bands of sst and wind anomalies stacked in the meridional direction with alternate polarities from the south atlantic all the way to greenland we propose that the interaction of wind evaporation and sst is key to establishing this interhemispherical pado based on results from a new ocean atmosphere coupling model forced by extratropical wind forcing the model successfully reproduces the observed decadal oscillation in both sst and wind velocity over the tropics this decadal extratropical forcing of the tropics is in sharp contrast to the well known tropics to extratropics teleconnection that operates on interannual time scales in association with el nino southern oscillation enso

equilibrium atmospheric response to north atlantic sst anomalies abstract the equilibrium general circulation model gcm response to sea surface temperature sst anomalies in the western north atlantic region is studied a coarse resolution gcm with realistic lower boundary conditions including topography and climatological sst distribution is integrated in perpetual january and perpetual october modes distinguished from one another by the strength of the midlatitude westerlies an sst anomaly with a maximum of 4 c is added to the climatological sst distribution of the model with both positive and negative polarity these anomaly runs are compared to one another and to a control integration to determine the atmospheric response in all cases warming cooling of the midlatitude ocean surface yields a warming cooling of the atmosphere over and to the east of the sst anomaly center the atmospheric temperature change is largest near the surface and decreases upward consistent with this simple thermal response the geopotential height field displays a baroclinic

earthquakes the lessons of tohoku oki an exceptional data set documents surface deformation before during and after the earthquake that struck northeastern japan in march 2011 but models for assessing seismic and tsunami hazard remain inadequate

tracing phosphorous distributions in the surficial sediments of two eastern himalayan high altitude lakes through sequential extraction multivariate and hysplit back trajectory analyses phosphorous p fractionation of the surficial sediment of high altitude lakes hal i e p t tso and sella lakes of arunachal pradesh state india were studied with an objective to investigate the phosphorus availability in the environment nutrient status of the lake and the role of climate change moreover the variation in phosphorous fraction was investigated through mineralogical studies like grain size analysis and x ray diffraction the findings revealed that the surficial sediment of lakes are least influenced by anthropogenic sources since a slight increase in each of the p fractions was observed from year 2011 to 2012 except organic p loosely sorbed exchangeable phosphorous was found to be slightly high which was due to difference in atmospheric precipitation which is one of the strong factors in high altitude regions decrease in organic fraction of p indicated that lakes became more oligotrophic in nature mineralogical investigation shows that illite montmorillonite and montmorillonite are the main minerals in sella lake whereas montmorillonite and graphite are main minerals in p t tso lake factor analysis of seasonal data of p fractionation in surface sediments along with physical parameters of sella lake water indicates three factors for the 2011 data principle factors are ph ec oxide bound and organic p factor analysis of p t tso lake water indicates three factors for the 2011 data with principle factors are adsorbed p and authigenic p ph oxide bound p this study shows that except organic fractions all other fractions are increasing in the following year it implies that even at such remote high altitude locations p characteristics are changing year to year which sought for further investigation and enables hals to show the early impacts of climate change related changes a clear influence of long range transported air pollutants has been found through hysplit back trajectory models which needs to be substantiated through long term monitoring

spatial patterns of atmosphere ocean interaction in the northern winter abstract the variability of monthly mean sea surface temperature sst anomalies over the extratropical north atlantic and pacific and its relation to atmospheric circulation anomalies over the northern hemisphere during wintertime is investigated by applying eigenvector analysis to a 39 year dataset and correlating the time series of the resulting expansion coefficients with the hemispheric 500 mb height and sea level pressure fields in agreement with previous studies the simultaneous correlation between the tone series of the expansion coefficient of the first empirical orthogonal function eof 1 of north pacific sea surface temperature sst and the hemispheric 500 mb height field resembles the pacific north american pattern and the corresponding pattern for atlantic sst resembles the north atlantic oscillation in the vicinity of the conters of action of thew patterns the sst fluctuations associated with these modes explain on the order of half the variance of 500 mb height and slightly less of

oceanic influence on the north atlantic oscillation and associated northern hemisphere climate variations 1959 1993 the north atlantic oscillation nao ex hibits variations at interannual to multidecadal time scales and is associated with climate variations over eastern north america the north atlantic europe and north africa therefore it is very important to understand causes of these nao variations and assess their predictability it has been hypothesized based on observations that sea surface temperature sst and sea ice variations in the north atlantic ocean influ ence the nao we describe results of an ensemble of sixteen experiments with an atmospheric general cir culation model in which we used observed sst and sea ice boundary conditions globally during 1949 1993 we show that multiyear nao and associated climate variations can be simulated reasonably accurately if re sults from a large number of experiments are averaged we also show that the ambiguous results of previous nao modeling studies were strongly influenced by the ensemble size which was much smaller than that in the present study the implications of these results for understanding and predictability of the nao are dis cussed