stationary rossby wave propagation in a baroclinic atmosphere observational studies of teleconnections in both soisticial seasons have suggested various patterns of behaviour linked mainly to westerly jets and equatorial westerlies these have been interpreted using barotropic rossby wave theory and simulated using stationary forcing in barotropic models linearized about 300 hpa flows in this paper the relevant propagation behaviour is investigated using a baroclinic model with three dimensional climatological basic states time integrations are performed using localized thermal forcing as a wavemaker the propagation results are qualitatively very similar to those obtained with the barotropic model though there are quantitative differences the westerly jets still act as strong waveguides the shorter wavelengths and smaller wave activity speeds found with the baroclinic model are generally in better agreement with observation propagation into and from the upper tropospheric equatorial westerlies in the east pacific propagation across north america and propagation from europe across the arabian gulf are all found the extent to which upper tropospheric westerlies reach towards the equator influences the propagation into those regions barotropic models can only represent such behaviour if the basic state reflects the near equatorial upper tropospheric zonal wind structure

fluid inclusions in quartz from oceanic hydrothermal specimens and the bingham utah porphyry cu deposit a study with pixe and sxrf abstract individual natural fluid inclusions in quartz were selected for non destructive microprobe analysis by synchrotron x ray fluorescence sxrf and proton induced x ray emission pixe in order to compare and contrast the compositions of porphyry type ore forming brines and two types of ocean crustal brines the inclusions contained brines with high salt concentrations typically 20 40 wt total and one or more daughter crystals the x ray and proton beams produced detectable characteristic x rays for many elements and allowed the quantification of concentrations for many elements with atomic number z 14 fluid inclusions associated with the core of the bingham ut porphyry cu mo deposit contain nacl brines that also contain element typical range in ppm k 12 000 100 000 ca 17 000 mn 8000 fe 120 000 cu 8000 zn 5000 br 2000 these values are in good agreement with published estimates and results from sxrf and pixe experiments are generally consistent the bingham fluid compositions closely resemble brines from the porphyry mo cu deposit at questa nm inclusions from two suites of oceanic plutonic rock samples gave pixe results consistent with published sxrf analyses from other inclusions in the same samples new inclusion analyses from the mathematician ridge locality indicate the nacl brines also contain on average element ppm k 3500 ca 35 000 mn 4900 cu 400 zn 200 br 1000 new inclusion analyses from the oceanographer transform locality indicate nacl brines that also contain on average k 37 000 ca 35 000 mn 10 000 cu 400 zn 2200 br 1000 these values are calculated on the assumption that fe in the inclusions is 50 000 ppm compared to continental ore forming brines the oceanic brines have higher ca and lower k and cu concentrations

climate control of decadal scale increases in apparent ages of eogenetic karst spring water abstract water quantity and quality in karst aquifers may depend on decadal scale variations in recharge or withdrawal which we hypothesize could be assessed through time series measurements of apparent ages of spring water we tested this hypothesis with analyses of various age tracers 3h 3he sf6 cfc 11 cfc 12 cfc 113 and selected solute concentrations dissolved oxygen do no3 mg and so4 from 6 springs in a single spring complex ichetucknee springs in northern florida over a 16 yr period these springs fall into two groups that reflect shallow short group 1 and deep long group 2 flow paths some tracer concentrations are altered with cfc 12 and cfc 113 concentrations yielding the most robust apparent ages these tracers show a 10 20 yr monotonic increase in apparent age from 1997 to 2013 including the flood recession that followed tropical storm debby in mid 2012 this increase in age indicates most water discharged during the study period recharged the aquifer within a few years of 1973 for group 2 springs and 1980 for group 1 springs inverse correlations between apparent age and do and no3 concentrations reflect reduced redox state in older water positive correlations between apparent age and mg and so4 concentrations reflect increased water rock reactions concentrated recharge in the decade around 1975 resulted from nearly 2 m of rain in excess of the monthly average that fell between 1960 and 2014 followed by a nearly 4 m deficit to 2014 this excess rain coincided with two major el nino events during the maximum cool phase in the atlantic multidecadal oscillation although regional water withdrawal increased nearly 5 fold between 1980 and 2005 withdrawals represent only 2 5 of ichetucknee river flow and are less important than decadal long variations in precipitation these results suggest that groundwater management should consider climate cycles as predictive tools for future water resources

on the rossby wave source and the steady linear response to tropical forcing abstract a two level spectral model with a zonally homogeneous climate is used to study the steady response of a spherical atmosphere to tropical heating solutions are obtained by both averaging the time integration of the model and solving for the linear steady response it is found that the rossby wave source rws from a simple tropical heat source exhibits a relatively complicated horizontal structure that extends from the tropics into extratropical regions the strong extratropical component of the rws is important for the steady response in middle and high latitudes a decomposition of the solution using separately the components of the rws in tropical and extratropical regions shows that the responses to the tropical and extratropical rwss tend to cancel in middle and high latitudes the extratropical component of the rws may be understood by quasigeostrophic dynamics

fluid inclusion and h o isotope evidence for immiscibility during mineralization of the yinan au cu fe deposit shandong china abstract the fluid inclusion and h o isotope studies have provided the evidences for the source of ore forming fluids and helped to recognize two types of immiscibility and their relationships with mineralization hydrogen and oxygen isotopic geochemistry shows that the earlier ore forming fluids during the anhydrous skarn stage i and the hydrous skarn magnetite stage ii were mainly derived from magmatic water while the later fluids during the quartz sulfide stage iii and the carbonate stage iv were mainly from magmatic water mixed with small amounts of meteoric water various types of fluid inclusions including abundant vapor or liquid rich two phase aqueous inclusions daughter minerals bearing multiphase inclusions co2 h2o inclusions and less abundant liquid inclusions vapor inclusions and melt inclusions are present in hydrothermal minerals of different stages the liquid vapor fluid inclusions are mainly composed of h2o with significant amounts of co2 and a small amount of ch4 in the opaque bearing fluid inclusions the hematite and fahlore tetrahedrite were identified the homogenization temperature of the aqueous fluid inclusions decreases from stage i 520 410 c through stage ii 430 340 c and iii 250 190 c to stage iv 190 130 c the coexistence of melt inclusions with simultaneously trapped vapor or liquid rich two phase aqueous inclusions and daughter minerals bearing multiphase inclusions in garnet diopside and epidote of stages i and ii suggests an immiscibility between silicate melt and hydrothermal fluid it is an effective mechanism on scavenging and transporting ore forming components from magmas the aqueous fluid inclusions with various vapor liquid ratios from 65 commonly coexist with simultaneously trapped liquid inclusions vapor inclusions daughter minerals bearing multiphase inclusions and co2 h2o inclusions in the quartz of stage iii and the different kinds of the fluid inclusions have similar homogenization temperatures this indicates that the boiling another kind of immiscibility widely took place during stage iii it resulted in the precipitation and enrichment of gold copper and iron

peralkaline granitoid magmatism in the mongolian transbaikalian belt evolution petrogenesis and tectonic significance article i nfo the central asian orogenic belt caob is well known for its massive generation of juvenile crust in the phanerozoic in eastern caob voluminous peralkaline and alkaline alkali feldspar granitoids and genetically related bimodal volcanics were emplaced in three stages from early permian to late mesozoic 295 270 ma 230 190 ma and 150 120 ma they occur as huge granitoid belts in extensional tectonic settings and form a complex network of about 12 million km 2 in area among them the 2500 km long mongolian transbaikalian belt mtb is the most spectacular and it comprises more than 350 granite syenite plutons and stocks with numerous co genetic volcanic fields the three stages of granitoids have similar chemical compositions but show temporal variation in nd isotopic composition initial end t values range from 1t o 5 for the early permian 0 to 4 for the early mesozoic and 2t o 3 5 for the late mesozoic granitoids the negative end t values observed in the mtb are not typical of the caob granitoids which are generally characterized by positive values however several pieces of evidence suggest that the mtb peralkaline and alkali feldspar granitoids were produced from enriched mantle derived sources the evidence includes 1 felsic and mafic rocks formed in the same stage have similar initial nd sr isotopic ratios and sm nd model ages tdm 2 the granitoid belts extend over thousands of kilometers and intersect distinct crustal provinces but no correlation is found in chemical compositions between the granitoids and country rocks 3 the abundant syenites are considered to be cogenetic or in some cases parental to the granites experimental and isotope data argue for the derivation of syenites from an enriched mantle source thus the granites and comendites are regarded as mantle derived 4 a study of melt inclusions in quartz phenocrysts of comendite indicates a high liquidus temperature of 1000 1100 c for the magma generation this suggests that the silicic magma was generated in an unusually high temperature condition which is likely produced by basaltic magma that underplated the lower crust the generation of voluminous peralkaline and alkaline alkali feldspar granitoids and genetically related bimodal volcanic rocks represents an important addition of juvenile crustal mass to the earth s continental crust during a time span of about 150 ma from late paleozoic to late mesozoic

the composition of hypersaline iron rich granitic fluids based on laser icp and synchrotron xrf microprobe analysis of individual fluid inclusions in topaz mole granite eastern australia abstract high temperature 550 c hypersaline 50 wt salts fluid inclusions representative of the earliest hydrothermal fluids associated with the sn w cu pb zn mineralised mole granite of eastern australia are well developed in topaz from the fielders hill locality methods based on inductively coupled plasma emission spectroscopy following laser ablation and on synchrotron x ray fluorescence microanalysis are described and applied to the semiquantitative point analysis of these inclusions crushleach analysis provides further information as well as highlighting the importance of point methods when several generations of inclusions are present the laser icp results confirm the dominance of fe k and na in these early high temperature fluids the mean fe k na atomic ratios 0 95 0 79 1 00 are entirely in agreement with published experimental data on the composition of chloride brines in equilibrium with synthetic granite at magmatic temperatures and support the view that these fluids are direct products from a cooling granite magma a number of trace and minor elements have also been detected in the inclusions these include ca mg li b be ba sr and several of the ore metals order of magnitude estimates of the ore metal contents of these fluids based on combined xrf microprobe and laser icp analysis are in the percent range for fe mn and zn in the range from several hundred to several thousand ppm in the case of sn cu and pb and less than 600 ppm for mo and w these results have important implications for ore genesis in granitic environments and point to the very high ore carrying potential of high temperature hypersaline chloride rich brines exsolved from cooling granite magmas

exsolution of magmatic volatile phases from cl enriched mineralizing granitic magmas and implications for ore metal transport abstract to understand cl dissolution in aluminosilicate liquids and the exsolution of cl rich magmatic volatile phases experiments were conducted to determine the solubility of nacl kcl and h2o in felsic liquids at 0 5 and 2 kbar the cl content of h2o poor nacl saturated and kcl saturated silicate liquids is low i e 1 3 wt to very low i e 0 2 wt and varies with changes in pressure and composition the cl concentration increases with the f concentration and the molar al na ca mg si ratio of the liquid and decreases with increasing activity of h2o in the system exsolution of a volatile phase depends on the partial pressures of all dissolved volatiles and low cl solubilities in nacl saturated and kcl saturated silicate liquids imply that exsolution of a cl bearing volatile phase will occur early in cl bearing granitic magmas i e prior to extensive melt crystallization and or at comparatively low water fugacities the solubility behavior of h2o and cl is very similar to that of co2 and h2o in felsic liquids small quantities of co2 are known to facilitate volatile phase exsolution holloway 1976 and in a similar manner volatile phases may exsolve early in cl enriched granite magmas whereas 5 to 6 wt dissolved h2o is necessary for volatile phase exsolution from a co2 free and cl free haplogranite liquid at 2 kbar and 800 c a cl rich brine will exsolve if the liquid contains only 1 wt h2o and 0 26 wt cl at the same conditions these new solubility data are interpreted in light of h2o f and cl concentrations in felsic liquids determined from silicate melt inclusions to constrain the exsolution of cl bearing magmatic volatile phases from mineralizing granitic magmas felsic magmas genetically associated with cu porphyry and mo porphyry mineralization contain sufficient h2o and cl to become saturated with respect to a hypersaline brine without strong pressure reduction boiling of the volatile phase i e exsolution of immiscible vapor and brine or strong volatile enrichment resulting from extensive crystal fractionation experiments were also conducted to investigate the solubility of mo in highly saline volatile phases coexisting with granitic liquids at 2 and 0 5 kbar the apparent partition coefficient for mo in the volatile phase s relative to silicate liquid d mo is defined as the computed concentration of mo in a volatile phase or phases the measured concentration of mo in granite glass d mo ranges from 8 to 80 as the nacl and kcl content of the volatile phase s increases from 15 to 90 wt because mo does not complex with cl in aqueous fluids it appears that mo solubility may be a strong function of the activity of na and k in alkali chloride rich volatile phases

southern european rainfall reshapes the early summer circumglobal teleconnection after the late 1970s the summer circumglobal teleconnection cgt which crucially affects mid latitude climate in the northern hemisphere is generally characterized by a mid latitude wave train along the strong upper tropospheric westerly jet in this study a significant change is identified in the spatial pattern of the early summer cgt after the late 1970s an additional high latitude wave train has occurred over northern eurasia based on observational evidences and simulation results with a linear baroclinic model it is proposed that the post 1970s cgt change is induced by enhanced impact of rainfall over southern europe se after the late 1970s specifically the mid latitude wave train of cgt in early summer is dominated by indian rainfall before the late 1970s but by both rainfall over india and se after the late 1970s the high latitude wave train of cgt occurring after the late 1970s however is induced only by the se rainfall the coupled indian and se rainfall after the late 1970s which is probably due to the basic flow change over the north atlantic induce both mid latitude and high latitude wave trains of the cgt

the influence of oxygen fugacity on tungsten and molybdenum partitioning between silicate melts and ilmenite the partitioning of molybdenum and tungsten between ilmenite ilm and silicic melts has been determined at 800 degrees c 1 kbar of pressure and at two oxygen fugacities at the oxygen fugacity of the graphite methane water buffer d super ilm melt mo 0 42 and d super ilm melt w 0 39 near the nickel nickel oxide buffer d super ilm melt mo 0 22 and d super ilm melt w 0 5 the variations in the partition coefficients with f sub o 2 are significant at the 0 06 and 0 33 levels for molybdenum and tungsten respectively the observed variation with oxygen fugacity is tentatively extrapolated to more complex systems and implies that the oxygen fugacity which prevails during magmatic crystallization may play a role in determining the mo w ratio in porphyry skarn or other hydrothermal mineral deposits examination of the literature on molybdenum and tungsten bearing mineral deposits indicates that systems with high w mo ratios are rather reduced and exhibit high ch 4 co 2 ratios in fluid inclusions low fe super 3 fe super 2 ratios in iron bearing minerals and low oxygen fugacities in associated igneous rocks on the other hand deposits with high mo w ratios are associated with rather oxidized magmatic systems we suggest that f sub o 2 dependent sequestration of molybdenum and tungsten in ferromagnesian phases during plutonic consolidation exerts a control on the relative efficiencies of removal of these metals from magmas into ore forming fluids

direct evolution of w rich brines from crystallizing melt within the mariktikan granite pluton west transbaikalia uneconomic tungsten mineralization associated with the mariktikan granite pluton of the transbaikalian igneous province eastern siberia is confined to a marginal part of the pluton referred to as the andreyevsky body this is composed of rocks similar to those of the main pluton but is likely to be an autonomous although kindred body on the basis of cross cutting relationships between rock varieties and their textural features the crystallization history is subdivided into three stages of unequal duration melt and fluid inclusions related to each of them have been studied using microthermometric and micro analytical procedures including a technique for atomic emission spectroscopy of individual fluid inclusions opened by a laser microprobe during the main crystallization stage 1045 1012 c more than 70 of the parental magma is believed to have crystallized at the level studied resulting in the formation of a crystalline framework rigid enough for the appearance of fractures within which some portion of the intercrystalline melt accumulated giving rise to thin aplite veins almost complete crystallization of intercrystalline and fracture hosted melt occurred during the late stage 1012 990 c whereas during the final stage only small bunches of schlieric sometimes miarolitic pegmatite were formed from a few pockets of residual melt 990 917 c in spite of the low water content of the melt about 1 wt fluid separation took place from the onset of crystallization during the main crystallization stage the exsolved fluid divided into two immiscible phases co2 rich gas and salt rich liquid brine however it was homogeneous thereafter major ore components of the brine mn fe w displayed different behaviour as crystallization progressed w concentration was below 0 1 wt at the main stage attained 1 wt during the late stage and increased to 1 8 wt at the final stage comparison of these data with calculations carried out using estimated parameters for the parental magma enables us to infer that obtained concentration values are reasonable for the special case studied here however they are unlikely to be attainable if the magma is h2o enriched and lacks an anomalously high w content in the andreyevsky body of the mariktikan pluton the following features of the parental magma made possible the generation of w rich solutions 1 high liquidus temperature 1045 c and elevated cl content c 0 15 wt that resulted in enlargement of the fluid melt distribution coefficient c 10 2 low water content c 1 and elevated w content c 0 001 wt that provided a relatively high w h2o ratio within the system at the same time because of the low water content of the magma the total mass of w bearing solutions has proved to be insufficient for the production of large scale mineralization a reduced w content of the great bulk of the exsolved brine may have had an unfavourable effect as well

why the western pacific subtropical high has extended westward since the late 1970s the western pacific subtropical high wpsh is closely related to asian climate previous examination of changes in the wpsh found a westward extension since the late 1970s which has contributed to the inter decadal transition of east asian climate the reason for the westward extension is unknown however the present study suggests that this significant change of wpsh is partly due to the atmosphere s response to the observed indian ocean western pacific iwp warming coordinated by a european union s sixth framework programme understanding the dynamics of the coupled climate system dynamite five agcms were forced by identical idealized sea surface temperature patterns representative of the iwp warming and cooling the results of these numerical experiments suggest that the negative heating in the central and eastern tropical pacific and increased convective heating in the equatorial indian ocean maritime continent associated with iwp warming are in favor of the westward extension of wpsh the sst changes in iwp influences the walker circulation with a subsequent reduction of convections in the tropical central and eastern pacific which then forces an enso gill type response that modulates the wpsh the monsoon diabatic heating mechanism proposed by rodwell and hoskins plays a secondary reinforcing role in the westward extension of wpsh the low level equatorial flank of wpsh is interpreted as a kelvin response to monsoon condensational heating while the intensified poleward flow along the western flank of wpsh is in accord with sverdrup vorticity balance the iwp warming has led to an expansion of the south asian high in the upper troposphere as seen in the reanalysis

inter comparison exercises on dissolved gases for groundwater dating 1 goals of the exercise and site choice validation of the sampling strategy abstract two international inter comparison exercises devoted to dissolved gases and isotope analyses in groundwater used as tools for groundwater dating were organized in 2012 in france ides universite paris sud cnrs and osur universite rennes 1 cnrs the goal was to compare sampling and analytical protocols through results obtained by the community of groundwater dating laboratories the two exercises were gdat1 on three supply boreholes in a homogeneous sand aquifer of fontainebleau paris basin france and gdat2 on two supply boreholes shallow and deep in a fractured rock aquifer in french brittany this two step exercise is the first exercise which included a large number of gases and isotopes usually used in groundwater as dating tools and also permit to discuss the uncertainties related to sampling protocols issuing from each laboratory methods the two tests allowed 31 laboratories from 14 countries to compare their protocols for both sampling and analyses this paper presents the participants and parameters measured and focuses on the validation of the sampling strategy two laboratories analyzed cfc and sf6 samples collected at regular intervals during the sampling operations in order to verify water homogeneity the results obtained by the two reference laboratories along with monitoring of field parameters showed no clear trend of gas concentration or physic chemical properties it can be concluded that the pumped groundwater composition remained constant during sampling this study also shows the potential for relatively constant pumped groundwater composition from a specific well despite the complexity and or mixing processes that may occur at a larger scale in the aquifer

solubility and stability of beryl in granitic melts beryllium contents of granitic melts at saturation in beryl or chrysoberyl phenakite or quartz have been determined by forward and reverse direction experiments at 650 850 degrees c and 200 mpa using natural beryl or the compositionally equivalent mixture of phenakite alumina quartz added to metaluminous haplogranite peraluminous haplogranite and macusanite a peraluminous li b f and p enriched rhyolite obsidian from macusani peru chrysoberyl coexists with beryl or quartz in moderately to strongly peraluminous systems asi approximately or 1 05 the assemblage phenakite beryl chrysoberyl is stable in silica undersaturated bulk composition the beo content of the melts which ranged between 0 03 0 40 wt varies principally with temperature the solubility of beryl falls with decreasing t and with the activity product of beryl alpha beo 3 alpha al2o3 alpha sio2 6 beryllia contents are lowest in strongly peraluminous and quartz saturated haplogranite melts however the highest beo content measured in glass products occurs for the strongly peraluminous macusanite at 850 degrees c 4016 ppm we infer that the greater solubility of beryl in macusanite melt results from melt speciation reactions involving li f b and p for all bulk compositions studied the beo content of melt projects to a narrow range of similar values at low t near the solidus of haplogranite thus metaluminous to peraluminous granitic magmas with and without common volatile and fluxing components will if cooled to subsolidus temperatures have similarly low beo requirements for beryl saturation the small beo content of melt near the solidus of haplogranite results in a minor 10 degrees c depression of the freezing point compared to be free haplogranite melt the mean melt composition at the beryl saturated granite minimum shifts slightly toward quartz beryl is common in peraluminous granitic rocks in part because lower beo contents are required to saturate these melts in beryl and possibly because these melts acquire higher beo contents by mica melting reactions at their sources beryl is also a common constituent of border facies assemblages in granitic pegmatite dikes regardless of their asi values this early crystallization of beryl results from the low beo content required to saturate any granitic melt in beryl at the low t environments in which pegmatite dikes solidify

interdecadal variations of the silk road pattern abstractbased on several reanalysis and observational datasets this study suggests that the silk road pattern srp a major teleconnection pattern stretching across eurasia in the boreal summer shows clear interdecadal variations that explain approximately 50 of its total variance the interdecadal srp features a strong barotropic wave train along the asian subtropical jet resembling its interannual counterpart additionally it features a second weak wave train over the northern part of eurasia leading to larger meridional scale than its interannual counterpart the interdecadal srp contributes approximately 40 of the summer surface air temperature s variance with little uncertainty and 10 20 of the summer precipitation s variance with greater uncertainty over large domains of eurasia the interdecadal srp shows two regime shifts in 1972 and 1997 the latter shift explains over 40 of the observed rainfall reduction over northeastern asia and over 40 of the observed warming over eastern europe

the geochemical signature of fluid saturated magma determined from silicate melt inclusions in ascension island granite xenoliths abstract silicate glasses in crystal free to crystal poor melt inclusions from two coarse grained granite xenoliths in alkaline volcanic rocks of ascension island were analyzed for 29 major minor and trace elements for most constituents the glass compositions are similar to those of the volcanic whole rocks and the xenoliths we interpret the glasses to be chemically representative of granite melt the melt inclusions are silicic alkaline contain low s and p abundances and are enriched in h 2 o cl f and na relative to k inclusions from one xenolith contain 1 3 wt f on average whereas those from the other xenolith contain half that amount the melt inclusion compositions allow investigation of the means and extent of granite magma evolution the presence of magmatic fluid inclusions in close proximity to melt inclusions in the phenocrysts indicates that the granite melt was saturated in one or more volatile phases roedder and coombs 1967 the cl and h 2 o contents of the melt inclusions are consistent with the exsolution of volatile phase s at pressures of 3000 to 2000 bars the glasses also show trends involving the cl h 2 o ratio and the incompatible trace elements in melt that are indicative of melt evolution via crystal fractionation of volatile phase saturated melt these trends should be useful for recognizing volatile phase saturation in other cl enriched melts

dynamical processes related to the appearance of quasi stationary waves on the subtropical jet in the midsummer northern hemisphere statistical features of quasi stationary planetary waves were examined on the subtropical jet in the midsummer northern hemisphere by using objectively analyzed data and satellite data as a result a quasi stationary wave train that is highly correlated with the midsummer climate over japan was identified a clear phase dependency of the appearance of waves was also confirmed an analysis of temporal evolution and wave activity flux revealed that the eastward propagation of the wave packet starts in the middle east passes over east asia and reaches north america the anomaly pattern is strengthened through kinetic energy conversion near the entrance of the asian jet over the middle east the interaction between the anomaly pattern and the basic field contributes to the appearance of the anomalous wavelike pattern although the wave train is correlated with the anomaly of convective activity over the western north pacific and the indian ocean it is implied that internal dynamics are important in determining the statistical features of the appearance of anomalous quasi stationary waves on the subtropical jet

factors determining the extratropical response to equatorial diabatic heating anomalies abstract the steady linear response of a spherical baroclinic atmosphere to an equatorial diabatic heat source having a simple horizontal and vertical structure is examined this source is imposed upon representative zonally symmetric as well as zonally varying flows during the boreal winter two climatologies are considered one is a 6 year average of global observations analyzed at the european centre for medium range weather forecasts ecmwf the other is a 30 year average taken from a general circulation model gcm run at the geophysical fluid dynamics laboratory in princeton the extratropical response is found to be very sensitive to the basic state around which the governing primitive equations are linearized and in the case of the ecmwf climatology to the longitudinal position of the source with respect to the climatological waves there is also some sensitivity to the vertical level of maximum heating although again this is more evident in the case of the ecmwf basic state these results ar

identification of he sources and estimation of he ages in groundwater of the north china plain abstract dissolved helium concentrations and 3 he 4 he ratios were measured for 18 groundwater samples collected from the quaternary confined aquifers in the north china plain ncp the dissolved helium concentrations ranged from 1 10 7 to 1 10 6 cm 3 stp g 1 in the 14 samples from the central plain but was approximately two orders of magnitude higher between 6 10 6 and 9 10 5 cm 3 stp g 1 in 4 samples from the coastal plain based on these concentrations and the corresponding 3 he 4 he ratios varying from 0 09 to 0 55 r a where r a is the 3 he 4 he ratio of air the dissolved helium in groundwater in the central plain was identified to be primarily a mixture of atmospheric helium with radiogenic helium and a representative radiogenic helium ratio was estimated to be 0 035 r a despite the high fraction of terrigenic 4 he in the samples from the coastal plain their 3 he 4 he ratios were found to be significantly above this radiogenic value ranging between 0 20 and 0 37 r a indicating the presence of a mantle derived he component in this area about 2 4 mantle helium was estimated to be present in the groundwater of the coastal plain which probably is associated with the regional cangdong fault and tectonic activities based on the radiogenic he component 4 he ages of the groundwater in the central plain were calculated by assuming either pure in situ production or an external helium flux j 0 of 4 7 10 8 cm 3 stpcm 2 a 1 the estimated 4 he ages fall between 9 5 and 51 4 ka and are comparable to the 14 c ages suggesting that the results of 4 he dating are reasonable and can be an effective tool to estimate groundwater residence times under suitable conditions

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

shift in the summer rainfall over the yangtze river valley in the late 1970s 1 the summer rainfall over the middle lower valley of the yangtze river and over the whole eastern china experienced a notable regime shift in about 1979 this change is consistent with a simultaneous jump like change in the 500 hpa geopotential height 500 over the northern pacific the rainfall over the yangtze river valley is closely related to the 500 averaged over the area 20 25 n 125 140 e with a correlation coefficient of 0 66 for the period 1958 1999 since 1980 the subtropical northwestern pacific high snph has enlarged intensified and extended southwestward the changes in the snph are strongly associated with the variations of the sea surface temperatures ssts of the eastern tropical pacific and tropical indian ocean the anomalies of these ssts responsible primarily for the shift of the summer rainfall over the yangtze river through the changes in snph precede the 500 signals with different leading times

monsoons and the dynamics of deserts the existence of subtropical deserts such as the sahara has often been attributed to the annual mean zonal mean hadley circulation which shows strong descent in the subtropics however the zonal mean hadley circulation shows considerable evolution over the course of the year with very strong subtropical descent during winter but practically no zonal mean subtropical descent during summer when rainfall over the eastern sahara and the mediterranean is least charney 1975 proposed a biosphere albedo feedback mechanism whereby local anthropogenic effects related to over grazing could affect the radiative balance enhancing summertime diabatic descent and leading to desertification of the subtropics in general the present study which uses an idealized model suggests a monsoon desert mechanism for desertification whereby remote diabatic heating in the asian monsoon region can induce a rossby wave pattern to the west integral with the rossby wave solution is a warm thermal structure that interacts with air on the southern flank of the mid latitude westerlies causing it to descend this adiabatic descent is localized over the eastern sahara and mediterranean and over the kyzylkum desert to the south east of the aral sea by the mountains of north africa and south west asia trajectories indicate that the monsoon desert mechanism does not represent a simple walker type overturning cell instead the descending air is seen to be mainly of mid latitude origin it is speculated that the monsoon forced adiabatic descent may result in clear air and therefore a local diabatic enhancement which effectively doubles the strength of descent with this mechanism desertification can be forced by remote changes in monsoon strength rather than by local effects this conclusion is supported by the observed dramatic strengthening of descent over the mediterranean and east sahara during the onset of the asian monsoon and on the longer timescale by relating prehistoric lake levels to milankovitch monsoon forcing the latter may help to explain the perceived discrepancies between the palaeoclimate of the eastern sahara and the strength of a tropic wide monsoon the monsoon desert mechanism may not be confined to the asian monsoon alone and the existence of other monsoon climate regions over the globe may in a similar way explain the observed summertime strengthening of the oceanic sub tropical anticyclones and the existence of western continental deserts and mediterranean type climate regions

circulations of the west pacific jet stream abstract the jet stream of the west pacific is a very steady feature of the winter circulation with almost continuousintensification over east china and japan and weakening in the central pacific in this study the national meteorological center spectral forecast model with normal mode initialization is used as a tool to provide diagnostic elements in a region of nonstandard data sources cross sections transverse to the jet stream in its intensification zone show a deep single celled direct solenoidal circulation around a single frontal zone to be producing large increases of kinetic energy farther east in the central pacific a strong indirect solenoidal circulation produces a strong decrease of kinetic energy the irrotational wind components at jet stream levels are suggestive of an inertial cycle as part of the jet stream dynamics a simple model of a modified inertial cycle is integrated in which the geostrophicwind is allowed to vary as a function of the ageostrophic flow transverse to the jet a

the formation mechanism of the bonin high in august the bonin high is a subtropical anticyclone that is predominant near japan in the summer this anticyclone is associated with an equivalent barotropic structure often extending throughout the entire troposphere although the equivalent barotropic structure of the bonin high has been known for years among synopticians because of its importance to the summer climate in east asia there are few dynamical explanations for such a structure the present paper attempts to provide a formation mechanism for the deep ridge near japan we propose a new hypothesis that this equivalent barotropic ridge near japan is formed as a result of the propagation of stationary rossby waves along the asian jet in the upper troposphere the silk road pattern first the monthly mean climatology is examined in order to demonstrate this hypothesis it is shown that the enhanced asian jet in august is favourable for the propagation of stationary rossby waves and that the regions of descent over the eastern mediterranean sea and the aral sea act as two major wave sources second a primitive equation model is used to simulate the climatology of august the model successfully simulates the bonin high with an equivalent barotropic structure the upper tropospheric ridge is found to be enhanced by a height anomaly of more than 80 m at 200 hpa when a wave packet arrives sensitivity experiments are conducted to show that the removal of the diabatic cooling over the asian jet suppresses the silk road pattern and formation of an equivalent barotropic ridge near japan while the removal of the diabatic heating in the western pacific does not copyright 2003 royal meteorological society

dissolved gases in groundwater and groundwater dating methods how useful for hydrogeological modeling foreword to the special issue one of the major challenges in hydrogeology is the basic spatial lack of continuous data as this is restricted to available boreholes basic information is provided by the measurements of physical parameters e g porosity and permeability at the well scale information related to a larger part of the aquifer are provided for example by continuous measurement of piezometric levels or spring flow temporal information is extremely powerful in order to characterize aquifer functioning globally groundwater dating has thus been developed in order to provide time constraints in aquifer studies

tropical extratropical teleconnections in boreal summer observed interannual variability abstractmaximum covariance analysis is performed on the fields of boreal summer tropical rainfall and northern hemisphere nh 200 hpa height for the 62 yr period of record of 1948 2009 the leading mode which appears preferentially in summers preceding the peak phases of the el nino southern oscillation enso cycle involves a circumglobal teleconnection cgt pattern in the nh extratropical 200 hpa height field observed in association with indian monsoon rainfall anomalies the second mode which tends to occur in summers following enso peak phases involves a western pacific north america wpna teleconnection pattern in the height field observed in association with western north pacific summer monsoon rainfall anomalies the cgt pattern is primarily a zonally oriented wave train along the westerly waveguide while the wpna pattern is a wave train emanating from the western pacific monsoon trough and following a great circle the cgt is accompanied by a pronounced tropical extratropical seesaw in t

aluminous granite as a source magma of hydrothermal ore deposits an experimental study partition ratios of zinc and lead between synthetic granitic melts and aqueous phase were determined at 800 degrees c and under p sub h 2 o 3 5 or 0 25 kb two starting glasses in the system sio 2 al 2 o 3 cao na 2 o were prepared their bulk chemical compositions are similar i e sio 2 content of 75 65 percent in glass 1 and of 74 68 percent in glass 2 glass 1 is prepared to be slightly alkaline with 1 89 percent normative wollastonite and glass 2 is slightly aluminous with 2 42 percent normative corundum the partition ratio of sodium between aqueous fluid and melt k p na can be expressed by the following equation over the whole range of chloride concentrations in the aqueous solution m v cl mole kg regardless of the normative composition of the melt k p na 0 468 x m v cl however the partition ratio of zinc k p zn for the aluminous melt is more than two orders of magnitude larger than that for the alkaline melt k p zn varies with the square of the chloride concentration in the aqueous phase and is satisfied by the following two equations k p zn 9 40 x m v cl 2 aluminous melt 2 and k p zn 0 0833 x m v cl 2 alkaline melt 1 a similar contrast was also observed in the partition ratios of lead between aqueous phase and melts k p pb 2 26 x m v cl 2 aluminous melt 2 and k p pb 0 0474 x m v cl 2 alkaline melt 1 the log of the partition ratio shows an excellent inversely proportional relation with the ph at 25 degrees c of the aqueous solution which was equilibrated with granitic melts and quenched a slope of 2 is obtained for alkaline melt and is reasonably explained by the equation pbo melt 2h super vapor 2cl super vapor pbcl sub 2 vapor h 2 o the slope for the aluminous melt 1 2 may be explained only by complex reactions involving silicate ligands in the melt the results indicate that only aluminous granite is capable of producing hydrothermal fluids which would contain a significant amount of ore metals in other words aluminous granite can be ore bearing by postmagmatic processes this is likely to happen when a granitie magma which originally was slightly alkaline changed its composition to slightly aluminous during diapiric uplift by assimilation of pelitic sediments if this compositional evolution happened then granitic magma would tend to store up base metals during the early stages of its evolution and release them very efficiently in the later stages to form a hydrothermal ore solution

microthermometric study of silicate melt inclusions in variscan granites from se germany volatile contents and entrapment conditions melt inclusions in granitic rocks are generally crystalline and must oberpfalz regions along the northern margin of the be homogenized to glass before analysis we employ a simple kinetic bohemian massif some of these granites particularly in technique with microthermometry to estimate total volatile contents the german erzgebirge are highly evolved geochemically and p t conditions of trapping of the melts from their hoand famous for the tin and uranium mineralization mogenization behaviour this information complements chemical associated with them several publications have condata from microprobe or ion probe analysis and can be obtained centrated on the geology geochemistry and ore from inclusions too small for direct analysis we present here values associations of the granites forster tischendorf 1994 for volatile contents as equivalent wt h2o trapping temperatures seltmann 1994 tischendorf forster 1994 hecht et and trapping pressures derived from studies of melt inclusions in some al 1997 siebel et al 1997 but their magmatic volatile variscan granites of the erzgebirge fichtelgebirge and oberpfalz contents and emplacement level are difficult to determine germany the volatile concentrations range from 3 to 10 equiv wt and have not often been addressed the granites from h2o microprobe analysis shows that the most volatile rich these regions contain abundant melt inclusions and these inclusions contain up to 8 wt f estimates of trapping offer the potential of constraining melt water contents pressures and temperatures suggest that crystallization began at an and conditions of trapping emplacement level of 3 6 5 km near 700 c with normal biotite all three regions contain composite plutons or plutonic and two mica granites and ended with topaz albite granite complexes which range in composition from un 650 c and pegmatitic phases down to 520 c this wide differentiated biotite granites to more highly evolved tworange of trapping temperatures and volatile contents is a general mica granites and finally to extremely evolved granites feature of melt inclusions in granites many of the granites studied containing li micas and topaz in some cases this comare highly evolved geochemically but the extreme volatile enrichment positional range is covered by different units of a single typical for these also occurs locally in the unspecialized granites pluton e g falkenberg granite oberpfalz whereas in other places individual plutons are more restricted in composition the erzgebirge region is particularly rich

contribution of the phase transition of pacific decadal oscillation to the late 1990s shift in east china summer rainfall based on our previous study the interdecadal changes in summer rainfall over east china in the late 1990s are further explored here the increased local rising motion is implicated as the dominant factor of increased rainfall in the lower huang huai river valley lhr both the observation and numerical experiments using community atmosphere model version 4 suggest that the negative pacific decadal oscillation pdo mode can result in rising anomalies and thus more rainfall in the lhr the east asian westerly jet stream eawjs is suggested as a bridge to link the pacific sea surface temperature anomalies and east asian summer rainfall model results reveal that the negative pdo mode can lead to significant easterly anomalies over east asia as a result the eawjs is weakened and shifts poleward which coincides with observed changes in eawjs after the late 1990s in addition weakened and poleward shifted eawjs can result in an anomalous ascending motion to its south in the lhr by modulating the jet related secondary meridional vertical circulation consequently rainfall increased in the lhr after the late 1990s besides the positive atlantic meridional oscillation can only induce insignificant changes over east asia and partly counteract the negative pdo effect there

structure and dynamics of the summertime pacific japan teleconnection pattern convective activity over the tropical western pacific is known to influence the extratropical circulation over east asia in the boreal summer in the form of teleconnection called the pacific japan pj pattern but its structure and dynamics have not yet been studied in depth in this study a composite analysis is performed for 32 monthly events of enhanced convection observed to the east of the philippines the composited monthly mean vorticity anomalies associated with the pj pattern are elongated zonally with a distinct poleward tilt with height this structure differs fundamentally from a combination of the first baroclinic mode in the tropics and the barotropic structure in midlatitudes as has widely been accepted as a conceptual model of the pj pattern a wave activity flux points polewards only in the lower troposphere indicating that rossby wave teleconnection occurs primarily through a low level south westerly jet those tilted anomalies over the western pacific can effectively gain kinetic energy in the exits of the mean jet streams in the upper and lower troposphere and available potential energy ape in the presence of the vertically sheared jets the enhanced convection can generate ape effectively and the associated low level anomalous circulation acts to increase moisture supply into the convective region while enhancing evaporation from the pre warmed ocean surface it is thus hypothesized that the pj pattern may be regarded as a dynamical mode that can be effectively excited in the zonally asymmetric baroclinic mean flow associated with the asian summer monsoon with an efficient self sustaining mechanism through moist processes copyright 2006 royal meteorological society

circumglobal teleconnection in the northern hemisphere summer analysis of the 56 yr ncep ncar reanalysis data reveals a recurrent circumglobal teleconnection cgt pattern in the summertime midlatitude circulation of the northern hemisphere this pattern represents the second leading empirical orthogonal function of interannual variability of the uppertropospheric circulation the cgt having a zonal wavenumber 5 structure is primarily positioned within a waveguide that is associated with the westerly jet stream the spatial phases of cgt tend to lock to preferred longitudes the geographically phase locked patterns bear close similarity during june august and september but the pattern in july shows shorter wavelengths in the north pacific north america sector the cgt is accompanied by significant rainfall and surface air temperature anomalies in the continental regions of western europe european russia india east asia and north america this implies that the cgt may be a source of climate variability and predictability in the above mentioned midlatitude regions the cgt has significant correlations with the indian summer monsoon ism and el nino southern oscillation enso however in normal ism years the cgt enso correlation disappears on the other hand in the absence of el nino or la nina the cgt ism correlation remains significant it is suggested that the ism acts as a conductor connecting the cgt and enso when the interaction between the ism and enso is active enso may influence northern china via the ism and the cgt additionally the variability of the cgt has no significant association with the arctic oscillation and the variability of the western north pacific summer monsoon the circulation of the wave train shows a barotropic structure everywhere except the cell located to the northwest of india where a baroclinic circulation structure dominates two possible scenarios are proposed the abnormal ism may excite an anomalous west central asian high and downstream rossby wave train extending to the north pacific and north america on the other hand a wave train that is excited in the jet exit region of the north atlantic may affect the westcentral asian high and thus the intensity of the ism it is hypothesized that the interaction between the global wave train and the ism heat source may be instrumental in maintaining the boreal summer cgt

low frequency equatorial waves in vertically sheared zonal flow part i stable waves abstract the mechanism by which a vertically sheared zonal flow affects large scale low frequency equatorial waves is investigated with two level equatorial plane and spherical coordinates models vertical shears couple barolinic and barotropic components of equatorial wave motion affecting significantly the rossby wave and westward propagating yanai wave but not the kelvin wave this difference results from the fact that the barotropic component is a modified rossby mode and can be resonantly excited only by westward propagating internal waves the barotropic components emanate poleward into the extratropics with a pronounced amplitude while the baroclinic components remain equatorially trapped a westerly vertical shear favors the trapping of rossby and yanai waves in the upper troposphere whereas an easterly shear tends to confine them in the lower troposphere as such their westward propagation is slowed down by both westerly and easterly shears when the strength of the vertical shear varies w

immiscible phases of magmatic fluid and their relation to be and mo mineralization at the yermakovka f be deposit transbaikalia russia abstract melt and fluid inclusions in minerals from the peralkaline granite intrusion and associated mineralized country rocks from the yermakovka f be deposit were studied to characterize the behaviour of trace elements and exsolved fluids in the transition from magmatic to hydrothermal processes ore mineralization was mostly due to volatile release from a deep seated pluton for which crystallization history and fluid exsolution can be tracked by three batches of magma gr1 gr3 intruded at the level of the ore deposition to form the yermakovka stock each batch of the sequential granite group is found to intrude at decreasing temperature from 840 to 730 c and progressively increasing extent of crystallization of magma in the parental pluton this resulted in the enrichment of the ascending melts in h2o 3 9 to 6 1 wt f 2 6 to 4 1 wt and some incompatible elements zr nb th rb pb although the earliest evidence for the exsolution of homogeneous fluoride sulphate brine correlates with the final stage of the gr2 ascent the most intensive volatile s release from the emplaced magmas is shown to occur during their in situ crystallization which was associated with the separation of exsolved fluid into immiscible phases brine and low salinity solution compositions of these fluid phases are determined using atomic emission spectroscopy of the appropriate fluid inclusions opened by a laser microprobe and empa and sem eds analyses of daughter crystals the brine phase is enriched in mo mn be up to 17 8 and 0 3 g kg respectively and contains perceptible abundances of ce la pb zn whereas the low salinity phase is enriched only in be up to 0 6 g kg the selective mobilization of the metals from the melt into fluids is considered to result from the oxidized state of the melt and fluids peralkalinity of the melt during crystallization and high f content of the melt the immiscible fluid phases are shown to migrate together through the solidifying stock giving rise to the albitized granite that is enriched in molybdenite but devoid of be minerals in the country rocks solutions similar to the brine and low salinity phases of the magmatic fluid made up separate fluid flows which produced be and mo mineralization and were issued predominantly from the parental pluton both types of mineralization are nearly monometallic which suggests that of the metals jointly transported by the brine only mo and in part ce and la precipitated separately at the level where the low salinity solutions deposited be ores

immiscibility of magmatic fluids and their relation to mo and cu mineralization at the bangpu porphyry deposit tibet china abstract the coexistence of aqueous fluid inclusions and silicate melt inclusions in quartz phenocrysts from porphyrites at the bangpu porphyry mo cu deposit tibet china were examined to characterize the immiscibility processes during the magmatic to hydrothermal transition the physical and chemical environment during crystallization of the magmas has been reconstructed on the basis of microthermometric experiments and trace element microanalysis compositions of melt and brine fluid phases are determined using synchrotron radiation x ray fluorescence analysis sem eds and laser raman spectroscopy analyses brine fluids were directly exsolved by a crystallizing melt and the simultaneous entrapment of volatile rich brine fluid and volatile poor immiscible phases silicate melt occurred at 670 700 c and 1 6 1 95 kbar when the magma had h2o contents between 5 and 6 wt and crystal contents of 60 80 a later low density fluid with a higher mo concentration exsolved after about 80 90 crystallization had occurred this fluid contained significant concentrations of cl na k ca fe cu zn rb and small amounts of mn br and pb immiscibility of magmatic fluids can lead to different metal partitioning behaviors between residual melt and volatile phases which generate variable metal ratios copper was partitioned preferentially into the brine phase in contrast to the behavior observed in other porphyry cu deposits ore deposition by a dense brine could explain the partially deep cu mineralization condensation of brine from a later low density parental fluid could be an efficient mechanism to concentrate shallow cu mineralization and broadly distributed mo mineralization the source of the mo mineralizing fluids probably was a particularly large magma chamber that crystallized and fractionated at depth greater than upper continental crust level

oceanic forcings of the interdecadal variability in east asian summer rainfall abstractin this study it was found that the pacific decadal oscillation pdo and the atlantic multidecadal oscillation amo are shown to be the two major drivers of the interdecadal variability of summer rainfall over east asia the first leading mode pc1 of this interdecadal variability associated with an in phase variation of rainfall anomalies along the yangtze river valley and huanghe huaihe river valley in china is attributed to the pdo while the second leading mode pc2 associated with seesawlike rainfall anomalies between the yangtze river valley and huanghe huaihe river valley is attributed to the amo the amo teleconnects its influence to the east asian region and beyond through a circumglobal stationary baroclinic wave train extending from the atlantic ocean through the eurasian continent and extending to north america the amo also altered the nature of the pdo through this atmospheric teleconnection resulting in the occurrence of a different pdo pattern pseudo pdo between the 1

tritium and helium isotopes as hydrologic tracers in a shallow unconfined aquifer measurements of tritium and 3he in groundwater can be used to calculate the age of tritium in groundwater such combined measurements on water samples thus provide a powerful tool towards understanding fluid flow in the near surface saturated zone we report tritium and helium isotope measurements on waters from an unconfined aquifer associated with a low level nuclear waste storage area these values are used to calculate ages of tritium in groundwater from 0 1 to 6 years from the groundwater ages and a three dimensional flow net hydraulic conductivities of 3 3 10 6 to 5 5 10 6 ms 1 for five wells and extreme values from a single well of 18 10 6 and 97 10 6ms 1 are calculated these values agree with hydraulic conductivities obtained from conventional aquifer tests the high conductivity value may indicate an area of preferred fluid flow

role of subtropical precipitation anomalies in maintaining the summertime meridional teleconnection over the western north pacific and east asia abstract the meridional teleconnection patterns over the western north pacific and east asia wnp ea during summer have a predominant role in affecting east asian climate on the interannual time scale a well known seesaw pattern of tropical subtropical precipitation is associated with the meridional teleconnection and the subtropical precipitation anomaly has been previously viewed as a result of anomalous circulations associated with the teleconnection in this study however the authors suggest that subtropical precipitation anomalies in turn can significantly affect large scale circulations and may be crucial for maintenance of the meridional teleconnection diagnosis by using observational and reanalysis data indicates that the meridional teleconnection patterns are clearer in summers when the subtropical rainfall anomalies are greater the simulated results by a linear baroclinic model indicate that a subtropical heat source which is equivalent to the diagnosed positive subtropical precipitati

teleconnections from tropics to northern extratropics through a southerly conveyor rossby wave propagation theory predicts that rossby waves in a tropical easterly flow cannot escape from the tropics to the extratropics here the authors show that a southerly flow component in the basic state a southerly conveyor may transfer a rossby wave source northward thus a forcing embedded in the deep tropical easterlies may excite a rossby wave response in the extratropical westerlies it is shown that the southerly conveyor determines the location of the effective rossby wave source and that the extratropical response is relatively insensitive to the location of the tropical forcing provided that the tropical response can reach the southerly conveyor a stronger southerly flow favors a stronger extratropical response and the spatial structure of the extratropical response is determined by the extratropical westerly basic flows

interdecadal variability of summer climate over east asia and its association with 500 hpa height and global sea surface temperature interdecadal variability of summer climate rainfall and temperature in east asia china and japan and its association with the anomalies of geopotential heights at 500 hpa over the northern hemisphere nh global sea surface temperature ssta and outgoing longwave radiation olr were examined an abrupt change was found in the middle and by the end of the 1970s in the variations of time coefficients of the second mode of singular value decomposition svd2 for the summer rainfall and temperature in china the rainfall anomaly around 1977 1979 changes from above normal to below normal and the temperature changes from below normal to above normal in the southern and southwestern parts of china a similar interdecadal variability was also found in the summer climate variations in the southwest islands of japan the 500 hpa height anomalies related to the spatial pattern of svd2 shows a clear dipole pattern the negative center is located in mongolia and northeastern china and the positive center is located in middle and southern china the abrupt change of summer climate in the middle and by the end of the 1970s over the subtropical regions of east asia is characterized with the intensification and westward and southward extension of the western pacific subtropical high wpsh it is also observed in geopotential height variations over eurasia around 1977 1978 an abrupt change of sst over the tropical indian ocean and tropical western pacific was also found around 1976 1977 it is indicated that interdecadal variability of summer rainfall and temperature over east asia is largely influenced by the change of ssta and convective activity in the tropical indian ocean and tropical western pacific the convective activity over the tropical indian ocean and tropical western pacific is usually enhanced when the sst is warmer than normal so the subtropical high anomalies over the subtropical regions of east asia are intensified through the enhancement of a hadley cell as a result the subtropical regions of east asia including southern and southwestern china and the southwest islands of japan are covered by a positive height anomaly at 500 hpa where the temperature is above normal and the rainfall is below normal

impact of the atlantic multidecadal oscillation on the asian summer monsoon 1 the impact of the atlantic multidecadal oscillation amo on the asian summer monsoon is investigated using a coupled atmosphere ocean global general circulation model by imposing the amo associated sea surface temperature anomalies in the atlantic as boundary forcing and allowing atmosphere ocean interactions outside the atlantic the positive amo phase characterized by anomalous warm north atlantic and cold south atlantic leads to strong southeast and east asian summer monsoons and late withdrawal of the indian summer monsoon these changes of monsoons are mainly through coupled atmosphere ocean feedbacks in the western pacific and indian oceans and tropospheric temperature changes over eurasia in response to the imposed forcing in the atlantic the results are in agreement with the observed climate changes in china corresponded to the amo phases they suggest a non local mechanism for the asian summer monsoon variability and provide an alternative view to understanding its interdecadal variation during the twentieth century citation lu r b dong and h ding 2006 impact of the atlantic multidecadal oscillation on the asian summer monsoon geophys res lett 33 l24701 doi 10 1029 2006gl027655

tritiogenic3he in groundwater in takaoka 3he 4he ratios up to 3 5 times the ratio of atmospheric he were found in groundwater samples the3he enrichment can be attributed to radiogenic3he produced by in situ beta decay of3h this shows that tritiogenic3he is accumulating in confined waters from tritiogenic3he and3h concentrations ages of groundwaters can be calculated detection of tritiogenic3he gives a tool to trace a tritium contamination which occurred in the past and cannot be assessed only by the3h counting method

the compositional limits of fluid immiscibility in the system h2onaclco2 as determined with the use of synthetic fluid inclusions in conjunction with mass spectrometry abstract the compositional limits of fluid immiscibility in the system nacl h2o co2 were investigated from 500 to 700 c at pressures of 1 2 and 3 kbar synthetic fluid inclusions formed in quartz prisms were equilibrated with high temperature high pressure fluids in hydrothermal pressure vessels the inclusions were analyzed optically by mass spectrometry and by microthermometry the fields of immiscibility were defined as a function of temperature and pressure mass spectrometry was used to validate the existence of the immiscible fluids and to determine the co 2 h 2 o ratios of the two coexisting phases microthermometry i e the measurement of the melting temperature of solid sodium chloride was used in conjunction with the results of the mass spectrometry measurements to define the tie lines within the two phase fields isochores and the location of a portion of the isopleth were determined for composition nacl8 9 h2o76 1 co215 0

possible connection between pacific oceanic interdecadal pathway and east asian winter monsoon 1 this paper highlights the sst interdecadal variability over the eastern north pacific and its connection with east asian winter monsoon eawm on decadal timescales aside from pdo pattern the sst interdecadal variation is the most significant over ip region where there is the intense air sea interaction involved with eawm including both wind stress and latent heat flux a possible explanation for the phase change of pdo is related to the localized atmospheric forcing and the upstream winter monsoon ssta interdecadal variation over the ip regions is the bridge linking the coupled ocean atmosphere interaction between midlatitude pacific and the tropical pacific

partitioning of f between h2o and co2 fluids and topaz rhyolite melt implications for mineralizing magmatic hydrothermal fluids in f rich granitic systems fluid melt distribution coefficients for f have been determined in experiments conducted with peraluminous topaz rhyolite melts and fluids consisting of h2o and h2o co2 at pressures of 0 5 to 5 kbar temperatures of 775 1000 c and concentrations of f in the melt ranging from 0 5 to 6 9 wt the major element f and cl concentrations of the starting material and run product glasses were determined by electron microprobe and the concentration of f in the fluid was calculated by mass balance the h2o concentrations of some run product glasses were determined by ion microprobe sims the solubility of melt in the fluid phase increases with increasing f in the system the solubility of h2o in the melt is independent of the f concentration of the system with up to 6 3 wt f in the melt no evidence of immiscible silica and fluoriderich liquids was detected in the hydrous but water undersaturated starting material glasses 8 5 wt f in melt or in the water saturated run product glasses f concentrates in topaz rhyolite melts relative to coexisting fluids at most conditions studied however df wt f in fluid wt f in melt increases strongly with increasing f in the system maximum values of df in this study are significantly larger than those previously reported in the literature linear extrapolation of the data suggests that df is greater than one for water saturated peraluminous granitic melts containing 8 wt f at 800 c and 2 kbar df increases as temperature and as h2o h2o co2 of the fluid increase for topaz rhyolite melts containing 1 wt f and with h2o rich fluids df is independent of changes in pressure from 2 to 5 kbar at 800 c for melts containing 1 wt f and in equilibrium with co2 bearing fluids the concentrations of f in fluid increases with increasing pressure f and lithophile element enriched granites may evolve to compositions containing extreme concentrations of f during the final stages of crystallization if f in the melt exceeds 8 wt df is greater than one and the associated magmatic hydrothermal fluid contains 4 molal f such f enriched fluids may be important in the mass transport of ore constituents i e f mo w sn li be rb cs u th nb ta and b from the magma

interdecadal variations of the east asian winter monsoon and their association with quasi stationary planetary wave activity abstract interdecadal variations of the east asian winter monsoon eawm and their association with the quasi stationary planetary wave activity are analyzed by using the 40 yr european centre for medium range weather forecasts re analysis dataset and the national centers for environmental prediction national center for atmospheric research reanalysis dataset it is found that the eawm experienced a significant weakening around the late 1980s that is the eawm was strong during 1976 87 and became weak after 1988 this leads to an obvious increase in the wintertime surface air temperature as well as a decrease in the frequency of occurrence of cold waves over east asia the dynamical process through which the eawm is weakened is investigated from the perspective of quasi stationary planetary waves it is found that both the propagation and amplitude of quasi stationary planetary waves have experienced obvious interdecadal variations which are well related to those of the eawm compared to the period 1976

the generation of global rotational flow by steady idealized tropical divergence abstract tropical convective heating is balanced on the large scale by the adiabatic cooling of ascent the horizontal divergence of the wind above this heating may be viewed as driving the upper tropospheric rotational wind field a vorticity equation model is used to diagnose this relationship it is shown that because of the advection of vorticity by the divergent component of the flow the rossby wave source can be very different from the simple fd source often used in particular an equatorial region of divergence situated in easterly winds can lead to a rossby wave source in the subtropical westerlies where it is extremely effective this part of the source can be relatively insensitive to the longitudinal position of the equatorial divergence a divergence field which is asymmetric about the equator can lead to a quite symmetric rossby wave source for a steady frictionless flow the rossby wave source averaged over regions within closed streamfunction or absolute vorticity contours is under cert

fluid immiscibility in natural processes use and misuse of fluid inclusion data abstract many occurrences of fluid immiscibility in natural geologic systems have been reported recently most often from fluid inclusion studies however the interpretation of fluid inclusion data in terms of immiscibility sometimes suffers from ambiguity of the vocabulary insufficient knowledge of the immiscibility constraints and insufficient knowledge of the topology in the tpx space of natural fluid systems for such reasons some authors have been misled to erroneous interpretations the term chemical immiscibility is unambiguously redefined as a multiphase multicomponent equilibrium the consequences of this definition are directly derived from the phase rule and concern the possible equations that relate the various parameters temperature pressure volumes compositions to each other these equations already put constraints on the topology of the phase equilibria in fluid systems a particular expression of the phase rule is proposed which takes into account the multiphase constant bulk volume constant bulk composition constraints in fluid inclusions the consequences of such an expression are of major importance in fluid inclusion studies the phase relations of some simple systems that approximate quite efficiently the natural complex fluids are then detailed h2o nacl co2 ch4 h2o co2 h2o co2 nacl the effects of these topologies and of the supplementary constraints constant bulk composition and constant bulk volume assumed for fluid inclusions isopleth isochoric systems are discussed

intercomparison of tritium and noble gases analyses 3h 3he ages and derived parameters excess air and recharge temperature abstract groundwater age dating with the tritium helium 3 h 3 he method has become a powerful tool for hydrogeologists the uncertainty of the apparent 3 h 3 he age depends on the analytical precision of the 3 h measurement and the uncertainty of the tritiogenic 3 he component the goal of this study as part of the groundwater age dating interlaboratory comparison exercise was to quantify the analytical uncertainty of the 3 h and noble gas measurements and to assess whether they meet the requirements for 3 h 3 he dating and noble gas paleotemperature reconstruction samples for the groundwater dating intercomparison exercise were collected on 1 february 2012 from three previously studied wells in the paris basin france fourteen laboratories participated in the intercomparison for tritium analyses and ten laboratories participated in the noble gas intercomparison not all laboratories analyzed samples from every borehole the reproducibility of the tritium measurements was 13 5 the reproducibility of the 3 he 4 he ratio and 4 he ne ar kr and xe concentrations was 1 4 1 8 1 5 2 2 2 9 and 2 4 respectively the uncertainty of the tritium and noble gas measurements results in a typical 3 h 3 he age precision of better than 2 5 years in this case however the measurement uncertainties for the noble gas concentrations are insufficient to distinguish the appropriate excess air model if the measured helium concentration is not included while the analytical uncertainty introduces an unavoidable source of uncertainty in the 3 h 3 he apparent age estimate other sources of uncertainty are often much greater and less well defined than the analytical uncertainty

effects of subseasonal basic state changes on rossby wave propagation during northern summer 1 we investigated the impact of subseasonal basic state changes on rossby wave propagation between july and august our investigation was based on an experimental study that used a linear baroclinic model two sets of diabatic heating were imposed at the midlatitudes and the tropics it was found that by a principal component analysis the atmospheric response to diabatic heating reaches a steady state on day 15 thus the response to midlatitude forcing reveals eastward rossby wave propagation along the asian jet while that to tropical forcing shows a gill type response followed by propagation into the extratropics the basic state differences between july and august are mainly revealed by thermal and dynamical effects a strong land sea thermal contrast and meridional shift of the asian jet with regard to midlatitude forcing the rossby wave response under the august basic state is higher than that under the july basic state this can be attributed primarily to the dynamical effect of the basic state on the other hand the rossby wave response to tropical forcing shows stronger amplitude under the july basic state than the august basic state the response is caused mainly by both the thermal and dynamical effects of the basic state in addition the interdecadal change in the basic state induces a significant change in the rossby wave propagation the difference is most evident in the change to midlatitude forcing that is due to the dynamical effect of the basic state

partitioning of lithophile trace elements between h 2 o and h 2 o co 2 fluids and topaz rhyolite melt experiments have been conducted with h 2 o and h 2 o co 2 bearing fluids and melts of a cl f and lithophile trace element enriched vitrophyre associated with topaz rhyolite from spor mountain utah the starting material is mildly peraluminous and contains 1 25 wt percent f and 1 500 ppm cl the experiments were conducted with f sub o 2 controlled near ni nio at pressures of 0 5 to 4 kbars and at temperatures of 770 degrees to 950 degrees c fluid melt trace element distribution coefficients d i were calculated for li be b rb sr y zr nb cs ba ce th and u after ion microprobe analysis of starting material and run product glasses the concentration of element i in the fluid was calculated by mass balance and the fluid melt distribution coefficient d i was calculated as ppm by weight of i in fluid ppm by weight of i in melt the partitioning of li rb sr y nb cs and ce between aqueous fluids and melts of topaz rhyolite composition depends strongly on temperature and pressure at 0 5 kbars li rb sr y nb cs and ce concentrate in the fluid at temperatures or 900 degrees c at 2 kbars this same group of lithophile elements except for sr concentrate in the fluid at t or 900 degrees c be b and ba partition in favor of the melt at 0 5 and 2 kbars and at all temperatures of this study in the presence of co 2 free aqueous fluids at 4 kbars and at temperatures of 770 degrees to 950 degrees c all lithophile elements partition in favor of the melt this behavior for lithophile elements mimics that of published data on the partitioning of pb and zn between rhyolitic melts and cl bearing fluids previous studies have demonstrated an equivalent effect of pressure on the distribution of chalcophile trace elements between granitic melts and cl bearing aqueous fluids fluid melt distribution coefficients for the lithophile trace elements are significantly smaller for topaz rhyolite melts in equilibrium with mixed co 2 h 2 o fluids than for topaz rhyolite melts plus co 2 free aqueous fluids there is no evidence for co 2 complexing with the lithophile trace elements at pressures 6 m the data imply that the alkali elements m dissolve into the fluid as mcl 0 complexes and that ce dissolves into the fluid as a cecl 0 3 complex water saturated magmas of topaz rhyolite composition may become differentiated with respect to li cs and rb or ce y and nb if an aqueous fluid phase is evolved and moves through the magma under the influence of a temperature gradient that has a maximum temperature of at least 850 degrees to 900 degrees c