direct determination of the timing of sea level change during termination ii an outcrop within the last interglacial terrace on barbados contains corals that grew during the penultimate deglaciation or termination ii we used combined 230th and231pa dating to determine that they grew 135 8 0 8 thousand years ago indicating that sea level was 18 3 meters below present sea level at the time this suggests that sea level had risen to within 20 of its peak last interglacial value by 136 thousand years ago in conflict with milankovitch theory predictions orbital forcing may have played a role in the deglaciation as may have isostatic adjustments due to large ice sheets other corals in the same outcrop grew during oxygen isotope 18o substage 6e indicating that sea level was 38 5 meters below present sea level about 168 0 thousand years ago when compared to the 18o signal in the benthic v19 30 v19 28 record at that time the coral data extend to the previous glacial cycle the conclusion that deep water temperatures were colder during glacial periods

classification and composite diagnosis of extratropical cyclogenesis events in the southwest pacific abstract characteristic patterns of cyclogenesis in the southwest pacific region are identified from a sample of 40 developing cyclones during 1990 94 cases were chosen objectively to ensure a realistic sampling of typical rather than ideal events a subjective classification based on synoptic scale upper tropospheric flow signatures prior to cyclone intensification suggested four classes into which all but three cases fell three categories each containing about a quarter of the population involved direct coupling with the upper jet they represent cyclone formation beneath i the poleward exit region of a 300 hpa jet upstream from a diffluent trough class u ii the confluent equatorward entrance region of the upper wind maximum e and iii the upper jet exit region where the jet is downstream from the upper trough class d these are analogous to previously identified categories for the western north atlantic region a fourth class involved cyclones forming beneath a preexisting intense up

extratropical transition of tropical cyclones over the western north pacific part i evolution of structural characteristics during the transition process abstract the development of extratropical cyclone structural characteristics that resulted from the extratropical transition of typhoon ty david 1997 and ty opal 1997 over the western north pacific is examined david moved poleward ahead of a midlatitude trough that was moving eastward as the dominant midlatitude circulation feature over the western north pacific during the transition david coupled with the midlatitude trough which led to the evolution of an intense cyclone that became the primary circulation over the north pacific although opal also moved poleward ahead of a midlatitude trough the principal midlatitude feature over the western north pacific was a preexisting stationary cyclone over the kamchatka peninsula during transition opal weakened and became a secondary cyclone to the preexisting primary north pacific cyclone the structural characteristics of the evolving extratropical cyclone with respect to each case are examined in the context of the interaction between a vortex an

extratropical transition of southwest pacific tropical cyclones part ii midlatitude circulation characteristics abstract this second of two papers on extratropical transition et over the southwest pacific ocean focuses on the variability of et a climatology of et onset based on a previously described objective technique shows that et commences 15 of latitude nearer the equator on average than similar cases from the northern hemisphere characteristic midlatitude circulation patterns accompanying et near 30 s are identified by means of empirical orthogonal function eof analysis of 50 storms the first eigenvector pattern explaining nearly half the circulation variability expresses relaxed and enhanced pressure gradients south of the storm that define composites similar to cradled and captured classifications previously described for the southeast indian ocean the second eof distinguishes redeveloping from weakening storms reintensifying storms were located beneath strong cyclonic vorticity advection cva near the equatorward entrance region of an upper jet whereas the upper jet was well to the west of

a one million year long sequence of marine terraces on sumba island indonesia abstract an exceptional sequence of raised coral reef terraces is visible at cape laundi on the north coast of the island of sumba in the savu sea in which at least eleven terraces wider than 100 m six of them even being over half a kilometer wide are geomorphologically distinguishable between an ancient patch reef now at 475 m and the present sea level esr date estimations of almost unrecrystallized corals most of them in situ make possible a tentative identification of the terraces corresponding to isotope stages 15 ca 600 ka ago and 9 ca 330 ka ago when the uplift trend deduced from the present altitude of dated terraces 0 49 0 01 mm yr is extrapolated to the whole raised section most geomorphological features appear to correspond to interglacial stages of the astronomically calibrated oxygen isotope record up to stage 27 ca 0 99 ma beyond the matuyama jaramillo geomagnetic boundary the upper terraces would in this case be twice as old as previously estimated ca 0 5 ma main terraces seem to correspond to high sea levels at certain interglacial stages and substages but in some cases the action of low sea levels at glacial stages cannot be ruled out for terraces between 30 and 70 m in altitude th u and esr dates reveal that aragonitic corals at similar elevations may differ in age as much as 100 ka this can be explained by taking into account a polycyclic origin for several terraces reconstructions available of changes in the eustatic sea level during the last 250 kyr and the fact that coral reef development may have been scattered at some periods only without totally covering subjacent older formations the sumba sequence of marine terraces at cape laundi is among the longest and most complete for the past million years reported in the literature its relatively good state of preservation will probably give impetus to a number of new studies on the chemical physical isotopic morphological palaeoclimatic pedological ecological and diagenetic changes which have occurred during the past one million years

late quaternary coseismic uplift events on the huon peninsula papua new guinea deduced from coral terrace data up to six regressive terraces occur on the holocene raised reef tract and up to 15 occur on late pleistocene raised reef tracts along 40 km of coastline at huon peninsula papua new guinea we suggest that the regressive terraces represent repeated episodic uplift caused by great earthquakes ages of holocene coseismic uplift events are established by radiocarbon dating the late pleistocene events are bracketed by u series ages of the raised reef tracts on which they occur the mean recurrence interval of great earthquakes that caused the uplift events is 970 to 1165 years in the holocene and probably the same in the late pleistocene the interval ranged from about 200 to 1900 years the uplift rate increases parallel to the coast from northwest to southeast and the amplitude of coseismic uplifts generally increases similarly although some events produced uplift with little shore parallel tilting the mean amplitude of coseismic uplifts throughout the study area is 3 m in for both holocene and late pleistocene sequences large late quaternary landslides are numerous and some probably were triggered by the great earthquakes that caused coseismic uplift there appears to be no continuum between historical large earthquakes at huon peninsula of magnitudes 7 that produced no or only minor uplift and the great earthquakes represented by meter scale coseismic uplifts and very large landslides two tectonic subregions are recognized which were uplifted together by some holocene events but not by others there is no surface trace of holocene faulting between the subregions and a buried fault is thought to separate them

simulations of the extratropical transition of tropical cyclones contributions by the midlatitude upper level trough to reintensification abstract the extratropical cyclone development processes during the reintensification stage of an extratropical transition from a tropical cyclone tc are described using numerical simulations three control simulations without a tropical cyclone present examine the extratropical cyclogenesis associated with upper level troughs that are characterized as weak moderate and strong when no tropical cyclone is included in the simulation the minimum surface pressures attained with the weak moderate and strong troughs are 1003 991 and 977 mb respectively in all three cases the low tilts northwestward with height during intensification and the rainfall pattern and eventual occlusion are representative of classic extratropical cyclone development the interactions of a tropical cyclone with each of the three midlatitude circulation patterns are compared with the control simulations to illustrate the contributions to the extratropical transition of the tropical cyclone in the three trough with tc case

extratropical transition of southwest pacific tropical cyclones part i climatology and mean structure changes a database of tropical cyclone best track and intensity information for the southwest pacific ocean basin is used to construct a 28 year climatology for tropical cyclones that move into middle latitudes of the nine or so tropical cyclones that form each year an average of about three can be expected to migrate south of 358s with the greatest fraction in march storms entering the tasman sea west of new zealand nz move almost due south on average and retain greater intensity than those to the east of nz where storms decay quickly while moving rapidly away to the southeast storms east of nz are embedded in a stronger more zonal flow than those to the west which move poleward ahead of a larger amplitude trough during el nino years tropical cyclones that move into middle latitudes exhibit stronger zonal motion and occur over a wider range of longitudes than during la nina years storm intensity is only weakly correlated with concurrent sst anomalies suggesting that atmospheric circulation is the dominant influence on storm properties average structure changes during extratropical transition et are identified using the ncep ncar reanalysis dataset for a subset of 33 transitioning storms during 1980 97 composites are used to construct a three dimensional conceptual model of the transformation from a mature hurricane to an asymmetric baroclinic midlatitude cyclone southwest pacific tropical cyclones encounter the baroclinic westerlies early in their lives accounting for their average eastward and poleward motion at maximum average intensity near 208s baroclinic effects are already important with warm frontogenesis appearing in the southeast quadrant and outflow aloft into a downstream subtropical wind maximum that moves poleward with the storm by 258s the average tc has lost the characteristic symmetric anticyclonic outflow aloft and acquired the characteristics of a baroclinic midlatitude storm including regions of warm and cold frontogenesis a vertical motion dipole and a westward tilt with height from about 308s poleward a second upper tropospheric wind maximum appears west of the storm with strengthening cyclonic vorticity advection aloft below about 400 hpa the storm retains the vertical warm cyclonic core as it migrates poleward

coralgal composition of drowned carbonate platforms in the huon gulf papua new guinea implications for lowstand reef development and drowning abstract collision between the south bismarck plate and the northern edge of the australian plate has produced an actively subsiding foreland basin in the western huon gulf a series of drowned carbonate platforms and pinnacles are preserved on this margin due to a combination of this rapid subsidence and eustatic sea level changes over the last 450 ka we analyzed sedimentary and coralgal data from the platforms to better understand lowstand reef development and drowning in the huon gulf the recovered limestones are divided into five main sedimentary facies coral reef coralline foraminiferal nodule coralline foraminiferal crust halimeda and planktonic foraminiferal limestones based on a comparison with modern analogues in the indo pacific and elsewhere we identified coral reef deep fore reef slope deeper fore reef slope and pelagic hemipelagic paleoenvironmental settings an analysis of facies relationships and their paleoenvironmental meanings revealed lowstand corals reefs preserved at the top of the platforms that grew within 10 m of sea level two different coral assemblages were identified within this facies 1 a shallow high energy reef community characteristic of windward margins and limited to the deep platforms 1947 2121 2393 m and 2 another shallow community but indicative of more moderate lower energy reef conditions and limited to the middle 1113 1217 1612 m and shallow platforms 823 m the change from high to lower energy reef growth conditions suggests that oceanographic climatic conditions in the huon gulf have changed substantially through time primarily through the closure of the gulf as a result of tectonic rotation and uplift of the huon peninsula over the last 450 ka despite major environmental perturbations i e relative sea level and temperature changes the platforms and the shallow water coral reefs exposed at the top have been able to re establish themselves time and time again over the last 450 ka we also identified two different incipient drowning scenarios influenced by the rate of relative sea level rise more rapid drowning in the middle and deep platforms produced a thin veneer of coralline foraminiferal nodule and halimeda limestones over the shallow coral reef material while the slower drowning experienced by the shallowest platforms allowed thick coralline foraminiferal crust limestones to develop we recognize three main stages of platform development 1 initiation and growth characterized by shallow coral reef growth as the platforms grew close to sea level during the lowstands 2 incipient drowning marked by a shift to coralline foraminiferal nodule crust and halimeda limestones as the platforms began to drown during rapid eustatic sea level rise and continued subsidence and 3 the complete drowning of the platforms characterized by platform turn off increased bioerosion fe mn precipitation and pelagic hemipelagic sedimentation as the platform surfaces finally drop below the photic zone

the extratropical transition of hurricane irene 1999 a potential vorticity perspective extratropical transition et of tropical cyclones is common in all ocean basins where tropical cyclones recurve polewards after the tropical cyclone experiences et a rapid deepening can take place resulting in the development of a very large and deep extratropical cyclone the et of hurricane irene 1999 was an example of such an explosive et irene formed in the caribbean and experienced et as it moved poleward resulting in a low pressure system which deepened 39 hpa in 24 hours according to the met office analyses the extent to which the hurricane was responsible for the explosive extratropical development has been determined by performing met office unified model forecasts from initial states with and without the hurricane the circulation and temperature anomalies associated with the hurricane were removed from the initial state using potential vorticity inversion the moisture anomaly co located with the hurricane core was also removed the results show that an extratropical cyclogenesis event takes place regardless of the presence of the hurricane in the initial conditions however the hurricane makes a significant difference to the track and central mean sea level pressure evolution of the resulting extratropical cyclone when irene was present the track of the extratropical cyclone was more zonal and the cyclone deepening rate was twice as fast as when irene was not present these effects appear to be particularly associated with a negative potential vorticity anomaly and enhanced divergent flow in the region of the upper level outflow of the transforming hurricane rather than with the hurricane vortex results also show that the presence of the hurricane resulted in a significant downstream surface low development in the eastern atlantic copyright 2004 royal meteorological society

gps and seismological constraints on active tectonics and arc continent collision in papua new guinea implications for mechanics of microplate rotations in a plate boundary zone 1 the island of new guinea is located within the deforming zone between the pacific and australian plates that converge obliquely at 110 mm yr new guinea has been fragmented into a complex array of microplates some of which rotate rapidly about nearby vertical axes we present velocities from a network of 38 global positioning system gps sites spanning much of the nation of papua new guinea png the gps derived velocities are used to explain the kinematics of major tectonic blocks in the region and the nature of strain accumulation on major faults in png we simultaneously invert gps velocities earthquake slip vectors on faults and transform orientations in the woodlark basin for the poles of rotation of the tectonic blocks and the degree of elastic strain accumulation on faults in the region the data are best explained by six distinct tectonic blocks the australian pacific south bismarck north bismarck and woodlark plates and a previously unrecognized new guinea highlands block significant portions of the ramu markham fault appear to be locked which has implications for seismic hazard determination in the markham valley region we also propose that rapid clockwise rotation of the south bismarck plate is controlled by edge forces initiated by the collision between the finisterre arc and the new guinea highlands

the extratropical transition and precipitation distribution of hurricane floyd 1999 abstract several recent landfalling tropical cyclones e g dennis floyd and irene 1999 have highlighted a need for a refinement in the forecasting paradigms and techniques in the area of quantitative precipitation forecasting floyd proved to be a particularly challenging forecast problem as it was accompanied by catastrophic flooding over large regions of the east coast in spite of its relatively quick northward movement the extent and intensity of the precipitation distribution was strongly modulated by the storm s interaction with a midlatitude trough in an attempt to better understand and quantify the relevant dynamics during this interaction potential vorticity pv and quasigeostrophic perspectives are utilized as floyd approached the east coast precipitation shifted to the left of the storm track due to the presence of a deep midlatitude trough in the ohio valley the juxtaposition of a cold core pv anomaly associated with the midlatitude trough and a warm core pv anomaly associated with

synoptic scale diagnosis of the extratropical transition of a southwest pacific tropical cyclone abstract this is the first of two case studies on the transformation of tropical storms in the southwest pacific this study uses ecmwf analyses and observations to examine the behavior of tropical cyclone patsy in december 1986 prior to and during its transit to midlatitudes these analyses adequately depicted synoptic scale features during the extratropical phase but underestimated the inner core of strong wind during the hurricane phase interactions with troughs in the subtropical westerlies provided the impetus for the major motion and structure changes during patsy s life during the hurricane phase patsy was steered by the flow above 400 hpa the passage of a first trough to poleward led to disintegration of the characteristic tropical cyclone structure decay was due to shearing effects loss of upper level outflow and the transient incorporation of cooler air into the low level circulation a few days later patsy commenced moving rapidly south as a single center as ascent redeveloped in the p

subseasonal to interannual variability of rainfall over new caledonia sw pacific daily rainfall occurrence and amount at 55 stations over new caledonia nc 20 s 166 e are examined throughout the calendar year during 1980 2010 using a hidden markov model hmm daily rainfall variability is described in terms of six discrete rainfall states identified by the hmm three states are interpreted as trade wind regimes associated with persistent low level anticyclonic conditions and weak to strong easterlies the most prevalent state state 1 36 of days is dry everywhere and is characterized by an elongated anticyclone centered around australia nc is located on the eastern edge of this anticyclone this state is predominant from mid may to mid december and peaks in september the second most prevalent state state 2 27 of days and the last trade regime state 4 12 of days are most frequent in austral summer states 2 and 4 are associated with the subtropical anticyclone centered south of nc close to its climatological location in austral summer and light state 2 to moderate state 4 rainfall mostly along the windward coast a distinct state state 3 11 of days is mostly associated with wintertime extratropical eastward traveling troughs between new caledonia and new zealand inducing light rainfall over the sw of the main island of new caledonia the two last states 5 and 6 are infrequent 15 of days but account for almost 70 of total rainfall across the archipelago they occur mostly in austral summer with their frequency of occurrence peaking in late february early march these states are associated with synoptic wave traveling eastward from eastern australia leading to a strong influx of moisture from the equatorial latitudes when the associated cyclonic centre is located west of new caledonia the wettest state is also strongly modulated by intra seasonal 15 80 days variability these events contribute to intermittent southwestward shifts of the south pacific convergence zone from its mean location northeast of new caledonia on interannual timescales the occurrence of the rainfall states is modulated by el nino southern oscillation enso events the enso impact is strongest from mid august to march with more less frequent trade regimes 1 2 and less more frequent unstable trade regime 4 and states 5 6 during central pacific warm cold enso events stochastic simulations of daily rainfall occurrence and amount at the 55 stations are generated by using predictors based on nino 4 sea surface temperature index and a local intra seasonal 15 80 days olr index superimposed on a climatological annual cycle the cross validated skill peaks in september november

the influence of the downstream state on extratropical transition hurricane earl 1998 case study abstract the multitude of tropical extratropical interactions that occur during an extratropical transition et complicate the prediction and diagnosis of these extreme events this study focuses on the analysis of a double et and reintensification event that took place between 5 and 7 september 1998 ex hurricanes earl and danielle reintensified rapidly over the western and eastern north atlantic respectively a set of simulations designed to test the sensitivity of earl s et to features in the downstream state was run using a set of idealizations for a numerical model s initial and boundary conditions downstream of ex hurricane earl dynamic tropopause analyses and the pv thinking paradigm applied under the eady model highlight important developmental and structural differences between the tests in fact two distinct solution modes are diagnosed both in the control and in the sensitivity tests earl s et proceeds according to a baroclinic mode of redevelopment whereas danielle displays distinct

evidence of holocene uplift in east new britain papua new guinea 1 we present the first published evidence of uplift along the eastern coast of new britain papua new guinea based upon 230th dating of uplifted holocene coral reefs although uplift rates of the nearby huon peninsula are well constrained 2 3 m ka little is known about vertical motion along the eastern margin of new britain based upon relative sea level curves for papua new guinea present sample elevations and estimates of paleowater depth of four in situ holocene corals we calculate an average uplift rate of 1 6 0 4 m ka for the southeast coast of new britain we suggest underplating of subducted sediment as a possible mechanism for uplift of the reefs

pleistocene sea levels and tectonic uplift based on dating of corals from sumba island indonesia we collected and dated fossil corals from the uplifted reef tracts of sumba island mass spectrometry tims and ams was used to obtain reliable and precise radiochronological results it is possible to identify outcrops corresponding to major sea level high stands isotope stage 1 starting at 7 1 kyr bp 5a c a 86 kyr bp 5c c a 105 kyr bp 5e between 119 and 132 kyr bp and 9 c a 305 kyr bp the radiochronological data are thus broadly consistent with the timing of sea level fluctuations predicted by the astronomical theory of paleoclimates comparison with similar data from other terrace sequences and from benthic 18o records indicates that the average tectonic uplift rate at cape laundi sumba is on the order of 0 2 0 5m kyr the lowest values 0 3m kyr lead to the build up of polycyclic topographic terraces in which it is possible to find corals grown during different interstadial or even interglacial times

extratropical transition of tropical cyclones over the western north pacific part ii the impact of midlatitude circulation characteristics abstract two characteristic midlatitude circulation patterns labeled northwest and northeast are found to be associated with extratropical transition et of tropical cyclones over the western north pacific ocean although in both cases the tropical cyclone moves poleward ahead of a midlatitude trough the primary midlatitude circulation is either that trough or is a large quasi stationary cyclone to the northeast of the poleward moving tropical cyclone transition into a northwest pattern typically results in the development within 36 h of an intense extratropical cyclone that moves north northeast a tropical cyclone that moves into a northeast pattern enters into strong zonal flow between the primary midlatitude circulation and the subtropical ridge to the southeast these systems move rapidly eastward and do not intensify significantly during the 36 h following transition in part i of this study the et of typhoon ty david 1997 and the et of ty opal 1997 were investigated in terms of the form

structure and evolution of subtropical cyclone anita as evaluated by heat and vorticity budgets this paper explores the evolution of subtropical cyclone anita which occurred near the east coast of brazil 19 s 37 w in march 2010 thermodynamic and dynamic processes during anita s lifecycle are investigated using the heat and vorticity budget equations the cyclone developed with hybrid characteristics and moved anomalously to the southwest where it coupled with an upper level cut off low during the mature phase this coupling was the main dynamical mechanism for further cyclone deepening anita then remained quasi stationary about 30 s 47 w for two days due to an upper level dipole pattern which prevented earlier displacement of the upper level low counterpart when the dipole pattern dissipated the cyclone moved southeast and underwent extratropical transition whilst merging with a mid latitude frontal cyclone diabatic heating and horizontal temperature advection are found to be essential for the subtropical development during extratropical transition it is instead diabatic cooling together with adiabatic cooling and warm air advection that act as the main mechanisms to influence the local temperature tendencies at low levels low level cyclonic tendencies were mostly due to convergent flow and the residual vorticity partially destroyed the vorticity tendencies produced by the divergence term moreover in regions and levels where convection could explain some of the vorticity tendencies it is found that apparent sinks of cyclonic vorticity were related to negative vorticity due to divergence i e convergent flow whilst apparent sources were related to positive vorticity due to divergence i e divergent flow

the 2007 eruption of kelut volcano east java indonesia phenomenology crisis management and social response we focus in this paper on the processes and consequences of an unusual volcanic eruption at kelut volcano east java in november 2007 after two months of worrying precursor signs kelut volcano erupted but neither explosions nor the usual hazards observed during the historic eruptions happened e g ash falls volcanic bombs and pyroclastic flows instead of an explosive eruption the 2007 eruption was extrusive given than such an eruption could not be predicted the authorities had to manage a new situation we conducted interviews with nine stakeholders of the crisis management team and undertook a questionnaire based survey in the settlement nearest to the crater in order to understand how the authorities managed the crisis and how people reacted inquiries and questionnaires were carried out shortly after the end of the evacuation process when the volcano was still under surveillance for fear of an explosive phase the results display a real gap in what it takes to manage a crisis or live through a crisis this suggests that the unusual eruption pattern of kelut volcano was not the only factor of the misunderstanding between the authorities and the population these problems stem from more structural causes such as the lack of communication and information when there is a need to adapt to a new scenario in such a situation the inability of the crisis management system to take decisions underscored the intrinsic vulnerability of the population despite a hierarchical and strategic top down crisis management approach

the extratropical transition of tropical cyclone edisoana 1990 abstractdocumentation of southwest indian ocean swio tropical cyclones tcs and extratropical transition et events is sparse in the refereed literature the authors present a climatology of swio tc and et events for 1989 2013 the swio averages 9 tropical cyclones tcs per year in this modern era of these tcs 44 undergo extratropical transition et or four per year a case study of tc edisoana 1990 the most rapidly intensifying swio post et tc between 1989 and 2013 shows that extratropical interactions began when an approaching trough embedded in the subtropical jet stream stj induced et on 7 march as edisoana underwent et a subtropical ridge downstream amplified in response to poleward directed positive potential vorticity pv advection associated with diabatically convectively driven upper level outflow from tc edisoana this amplifying lower latitude ridge phased with a lower amplitude higher latitude ridge embedded in the polar front jet pfj resulting in the merger of the t