coordinated hydrological regimes in the indo pacific region during the past two millennia instrumental data suggest that major shifts in tropical pacific atmospheric dynamics and hydrology have occurred within the past century potentially in response to anthropogenic warming to better understand these trends we use the hydrogen isotopic ratios of terrestrial higher plant leaf waxes delta d wax in marine sediments from southwest sulawesi indonesia to compile a detailed reconstruction of central indo pacific warm pool ipwp hydrologic variability spanning most of the last two millennia our paleodata are highly correlated with a monsoon reconstruction from southeast asia indicating that intervals of strong east asian summer monsoon easm activity are associated with a weaker indonesian monsoon im furthermore the centennial scale oscillations in our data follow known changes in northern hemisphere climate e g the little ice age and medieval warm period implying a dynamic link between northern hemisphere temperatures and ipwp hydrology the inverse relationship between the easm and im suggests that migrations of the intertropical convergence zone and associated changes in monsoon strength caused synoptic hydrologic shifts in the ipwp throughout most of the past two millennia

varied response of western pacific hydrology to climate forcings over the last glacial period atmospheric deep convection in the west pacific plays a key role in the global heat and moisture budgets yet its response to orbital and abrupt climate change events is poorly resolved here we present four absolutely dated overlapping stalagmite oxygen isotopic records from northern borneo that span most of the last glacial cycle the records suggest that northern borneo s hydroclimate shifted in phase with precessional forcing but was only weakly affected by glacial interglacial changes in global climate boundary conditions regional convection likely decreased during heinrich events but other northern hemisphere abrupt climate change events are notably absent the new records suggest that the deep tropical pacific hydroclimate variability may have played an important role in shaping the global response to the largest abrupt climate change events

late quaternary paleoclimate in the eastern mediterranean region from stable isotope analysis of speleothems at soreq cave israel abstract the eastern mediterranean continental paleoclimate during the past 25 000 years was determined by a high resolution petrographic stable isotopic and age study of speleothems from soreq cave israel 18o 13c trends indicate that all speleothems older than 7000 yr formed under conditions that differ from those of today the period from 25 000 to 17 000 yr b p was characterized by the highest 18o and 13c values which indicate deposition at temperatures of 12 16 c annual rainfall of 300 450 mm and vegetation typical of a mixed c3 c4type from 17 000 to 10 000 yr b p deglaciation in northern europe 18o values dropped progressively correlative with warming 2 3 c and a gradual increase in precipitation a simultaneous decrease in 13c gives a range expected for c3 type vegetation this period also shows significant 18o and 13c spikes which are correlatable with global events e g heinrich events and the younger dryas stade the speleothems that grew between 10 000 and 7000 yr b p have a unique petrography showing irregular thin laminae of various colors and much detritus they have the lowest 18o corresponding to 1000 mm rain coupled with the highest 13c caused by flooding events which stripped the soil cover from 7000 to 1000 yr b p conditions became closer to those of today this study demonstrates that global events which were recognized in northern europe and north africa are also evident in the eastern mediterranean and are reflected principally by large changes in the rainfall rate

interglacial hydroclimate in the tropical west pacific through the late pleistocene records of atmospheric carbon dioxide concentration pco 2 and antarctic temperature have revealed an intriguing change in the magnitude of interglacial warmth and pco 2 at around 430 000 years ago 430 ka but the global climate repercussions of this change remain elusive here we present a stalagmite based reconstruction of tropical west pacific hydroclimate from 570 to 210 ka the results suggest similar regional precipitation amounts across the four interglacials contained in the record implying that tropical hydroclimate was insensitive to interglacial differences in pco 2 and high latitude temperature in contrast during glacial terminations drying in the tropical west pacific accompanied cooling events in northern high latitudes therefore the tropical convective heat engine can either stabilize or amplify global climate change depending on the nature of the climate forcing

low stable isotope ratios of tropical cyclone rains tropical cyclone rains have distinctly lower stable isotope ratios than rains in other tropical and summer precipitation systems with a mean value slightly above that of water vapor near the sea surface the isotope ratios also decrease radially inward to the eye wall but appear to be anomalously low even near the periphery of the rain shield these findings indicate that tropical cyclones are highly efficient precipitation systems and suggest the use of stable isotope ratios as dynamic tracers of a tropical cyclone s water and energy budgets

lessons learned from oxygen isotopes in modern precipitation applied to interpretation of speleothem records of paleoclimate from eastern asia abstract variability in oxygen isotope ratios collected from speleothems in chinese caves is often interpreted as a proxy for variability of precipitation summer precipitation seasonality of precipitation and or the proportion of 18o to 16o of annual total rainfall that is related to a strengthening or weakening of the east asian monsoon and in some cases to the indian monsoon we use modern reanalysis and station data to test whether precipitation and temperature variability over china can be related to changes in climate in these distant locales we find that annual and rainy season precipitation totals in each of central china south china and east india have correlation length scales of 500 km shorter than the distance between many speleothem records that share similar long term time variations in 18o values thus the short distances of correlation do not support though by themselves cannot refute the idea that apparently synchronous variations in 18o values at widely spaced 500 km caves in china are due to variations in annual precipitation amounts we also evaluate connections between climate variables and 18o values using available instrumental measurements of 18o values in precipitation these data from stations in the global network of isotopes in precipitation gnip show that monthly 18o values generally do not correlate well with either local precipitation amount or local temperature and the degree to which monthly 18o values do correlate with them varies from station to station for the few locations that do show significant correlations between 18o values and precipitation amount we estimate the differences in precipitation amount that would be required to account for peak to peak differences in 18o values in the speleothems from hulu and dongge caves assuming that 18o scales with the monthly amount of precipitation or with seasonal differences in precipitation insofar as the present day relationship between 18o values and monthly precipitation amounts can be applied to past conditions differences of at least 50 in mean annual precipitation would be required to explain the 18o variations on orbital time scales which are implausibly large and inconsistent with published gcm results similarly plausible amplitudes of seasonal cycles in amounts or in seasonal variations in 18o values can account for less than half of the 4 5 difference between glacial and interglacial 18o values from speleothems in china if seasonal cycles in precipitation account for the amplitudes of 18o values on paleoclimate timescales they might do so by extending or contracting the durations of seasons a frequency modulation of the annual cycle but not by simply varying the amplitudes of the monthly rainfall amounts or monthly average 18o values amplitude modulation allowing that several processes can affect seasonal variability in isotopic content we explore the possibility that one or more of the following processes contribute to variations in 18o values in chinese cave speleothems different source regions of the precipitation which bring different values of 18o in vapor different pathways between the moisture source and the paleorecord site along which exchange of 18o between vapor surface water and condensate might differ a different mix of processes involving condensation and evaporation within the atmosphere or different types of precipitation each may account for part of the range of 18o values revealed by speleothems and each might contribute to seasonal differences between past and present that do not scale with monthly or even seasonal precipitation amounts

volatile contents of phlogopite micas from south african kimberlite phlogopite micas from nodules in south african kimberlites were analyzed for major elements with the electron microprobe and for volatile contents by high temperature mass spectrometry the micas are from primary deformed and secondary undeformed textured grains in perodotite xenoliths glimmerites marid mica amphibole rutile ilmenite diopside suite nodules and a mica megacryst the major element and volatile contents of micas exhibiting these modes of occurrence overlap to a greater extent than indicated in previous studies concentrations of volatile species occupying structurally defined crystallographic sites h2o f cl are greater for many of the micas than predicted on the basis of the mica formula particularly for the glimmerite and marid suite samples a correlation exists between micas with tetrahedral and octahedral cation deficiencies and those with excess h2o f and cl substitution of h for tetrahedral and possibly octahedral cations may be responsible for the excess h2o in these micas except for one sample the major element and volatile data for the peridotite glimmerite and marid suite micas indicate that they crystallized at oxygen fugacities below the quartz fayalite magnetite buffer f and k2o are in the correct proportion in the micas to provide the source for these elements in alkali basalts but not in mid ocean ridge basalts kaersutite amphibole is a more likely source of potassium and fluorine in mid ocean ridge basalts

stable isotopic variations in west china a consideration of moisture sources 1 in this study individual precipitation samples collected over 2 years at stations in different climatic regions of west china tibetan plateau region tianshan region and altay were analyzed for the stable isotopes of precipitation to improve our understanding of how vapor transport impacts the modern stable isotopic distribution our results identify regional patterns in both 18o and deuterium excess d excess defined as d 8 18o and in particular we have identified the northward maximum extent of the southwest monsoon over the tibetan plateau this demarcation is also the boundary for the fractionation effect of temperature on stable isotopes in precipitation the patterns we have identified are as follows 1 in the southern tibetan plateau along the southern slope of the himalayas our results show a distinct seasonality for both 18o and d excess as a result of the shift of summer monsoon moisture and winter westerly moisture transport the signals of 18o in the western tibetan plateau reveal that the region receives southwest monsoonal moisture in the east of the plateau stable isotopic variation shows alternation between monsoon intrusion and recycling of northern moisture 2 in contrast in tianshan there is an apparent temperature effect in 18o with enriched values occurring in summer and depleted values occurring in winter seasonal d excess values opposite to those observed in the southern tibetan plateau are controlled by differing seasonal evaporation conditions 3 in altay the most northern mountain region the seasonal 18o shows the same variation with that in tianshan region however d excess shows no apparent seasonal variation

palaeoclimatic interpretation of high resolution oxygen isotope profiles derived from annually laminated speleothems from southern oman high resolution stable isotope profiles of three contemporaneously deposited stalagmites from a shallow cave in southern oman provide an annually resolved record of indian ocean monsoon rainfall variability for the past 780 years uranium series age dating and counts of annual growth bands enable an excellent age calibration although modern speleothems do not grow in perfect isotopic equilibrium oxygen isotope ratios 18o are a proxy for the amount of monsoon rainfall this is supported by the statistically significant correlation between 18o and the thickness of annual bands whereas 18o is inversely correlated with annual band thickness additionally overlapping 18o profiles are very similar in pattern and range indicating that sample specific noise did not blur the climatic signal the longest oxygen isotope profile derived from stalagmite s3 clearly shows the transition at 1320 ad from a generally wetter medieval warm period to a drier little ice age that lasted from approximately ad 1320 1660 in southern oman the decrease in monsoon rainfall since the 1960s is also obvious in meteorological records from northern africa and india indicating that our speleothem based rainfall records do not only reflect local monsoon rainfall variability

diurnal to interannual rainfall δ 18 o variations in northern borneo driven by regional hydrology the relationship between climate variability and rainfall oxygen isotopic 18o variability is poorly constrained especially in the tropics where many key paleoclimate records rely on past rainfall isotopes as proxies for hydroclimate here we present a daily resolved 5 yr long timeseries of rainfall 18o from gunung mulu national park located in northern borneo 4 n 114 e in the heart of the west pacific warm pool and compare it to local and regional climatic variables daily rainfall 18o values range from 0 7 to 18 5 and exhibit a weak but significant inverse relationship with daily local precipitation amount r 0 19 p 0 05 consistent with the tropical amount effect day to day 18o variability at mulu is best correlated to regional precipitation amount averaged over the preceding week r 0 64 p 0 01 the inverse relationship between mulu rainfall 18o and local regional precipitation amount increases with increased temporal averaging reaching r 0 56 r 0 72 on monthly timescales large negative multi day rainfall 18o anomalies of up to 16 occur every 30 90 days and are closely associated with wet phases of the intraseasonal madden julian oscillation a weak semi annual seasonal cycle in rainfall 18o of 2 3 bears little resemblance to seasonal precipitation variability pointing to a complex sequence of moisture sources and or trajectories over the course of the year interannual rainfall 18o variations of 6 8 are significantly correlated with indices of the el nino southern oscillation with increased rainfall 18o during relatively dry el nino conditions and vice versa during la nina events we find that mulu rainfall 18o outperforms mulu precipitation amount as a tracer of basin scale climate variability highlighting the time and space integrative nature of rainfall 18o taken together our results suggest that rainfall 18o variability at mulu is significantly influenced by the strength of regional convective activity as such our study provides further empirical support for the interpretation of 18o based paleo reconstructions from northern borneo stalagmites as robust indicators of regional scale hydroclimate variability where higher 18o reflects regional drying

precipitation over south america during the last glacial maximum an analysis of the amount effect with a water isotope enabled general circulation model low latitude paleoclimate records from speleothem 18o measurements are often considered to reflect variations in precipitation amounts here we test this interpretation with a water isotope enabled atmospheric general circulation model comparing modern and last glacial maximum lgm controls on the 18op in brazil we argue that the 18op is determined by the contributions from local evaporation high 18o versus water vapor convergence to the region low 18o our analysis indicates that the amount effect commonly used to infer precipitation amount from 18op in low latitude regions works only where the isotopic composition of incoming vapor stays relatively constant such as in coastal regions of the subtropics if the isotopic composition of incoming vapor has changed as a result of the variations in the upstream rainout 18op cannot be used to estimate local precipitation our analysis supports the increase of precipitation over northeastern brazil region during the lgm

the role of paleochannels in groundwater seawater exchange relict fluvial channels that are infilled with high permeability sediments act as preferred pathways for groundwater flow and solute transport in coastal regions such paleochannels can provide a hydraulic connection between freshwater aquifers and the sea facilitating saltwater intrusion landward or freshwater discharge offshore although paleochannels have been implicated in several instances of saltwater intrusion there has been little direct study of these channels to confirm their role in this work simulation modeling of a general multi layered coastal plain aquifer setting indicates that when a paleochannel breaches a confining unit offshore submarine groundwater discharge of intermediate salinity occurs this discharge is largely concentrated along the margins of the channel conversely seawater inflow occurs along the channel axis resulting in higher salinity in the middle of the channel relative to the flanks chirp seismic and electromagnetic data collected offshore wrightsville beach nc usa confirm these simulation results and indicate fresher porewater along channel flanks and slightly higher porewater salinity along the channel axis hence paleochannels contribute to the spatial variability in submarine groundwater discharge by serving as conduits of focused fluid exchange simulations also reveal that the freshwater saltwater transition zone is closer to land below paleochannels than in locations with a continuous confining unit this indicates that such channels are likely to be significant modes of saltwater intrusion into confined aquifers when excess freshwater extraction occurs on land

millennial scale trends in west pacific warm pool hydrology since the last glacial maximum models and palaeoclimate data suggest that the tropical pacific climate system plays a key part in the mechanisms underlying orbital scale and abrupt climate change atmospheric convection over the western tropical pacific is a major source of heat and moisture to extratropical regions and may therefore influence the global climate response to a variety of forcing factors the response of tropical pacific convection to changes in global climate boundary conditions abrupt climate changes and radiative forcing remains uncertain however here we present three absolutely dated oxygen isotope records from stalagmites in northern borneo that reflect changes in west pacific warm pool hydrology over the past 27 000 years our results suggest that convection over the western tropical pacific weakened 18 000 20 000 years ago as tropical pacific and antarctic temperatures began to rise during the early stages of deglaciation convective activity as inferred from oxygen isotopes reached a minimum during heinrich event 1 ref 10 when the atlantic meridional overturning circulation was weak pointing to feedbacks between the strength of the overturning circulation and tropical pacific hydrology there is no evidence of the younger dryas event in the stalagmite records however suggesting that different mechanisms operated during these two abrupt deglacial climate events during the holocene epoch convective activity appears to track changes in spring and autumn insolation highlighting the sensitivity of tropical pacific convection to external radiative forcing together these findings demonstrate that the tropical pacific hydrological cycle is sensitive to high latitude climate processes in both hemispheres as well as to external radiative forcing and that it may have a central role in abrupt climate change events

speleothem based paleoclimate record from northern oman u th age dating and stable isotope measurements of speleothems from hoti cave in northern oman yield paleoclimate information from the region extending to 125 ka the results 1 provide further confirmation of an early holocene wet period in southern arabia extending from some time prior to 9 7 ka and ending at 6 2 ka 2 demonstrate a second period of wetness closely coinciding with the last interglacial period marine isotope stage mis 5e 3 indicate that during mis 5e southern arabia was considerably wetter than during the early holocene and 4 demonstrate that periods of increased monsoon wind strength based on data from marine sediments do not always coincide with evidence of greatly increased precipitation even from nearby continental areas

coherent isotope history of andean ice cores over the last century 1 isotope records from andean ice cores provide detailed and high resolution climate information on various time scales however the relationship between these valuable isotope records and local or regional climate remains poorly understood here we present results from two new drillings in bolivia from the illimani and the sajama ice caps all four high altitude isotope signals in the andes now available huascaran quelccaya illimani and sajama show near identical decadal variability in the 20th century comparison with general circulation model results and meteorological data suggest that the andean high altitude records are primarily controlled by precipitation variability over the amazon basin

a high resolution absolute dated late pleistocene monsoon record from hulu cave china oxygen isotope records of five stalagmites from hulu cave near nanjing bear a remarkable resemblance to oxygen isotope records from greenland ice cores suggesting that east asian monsoon intensity changed in concert with greenland temperature between 11 000 and 75 000 years before the present yr b p between 11 000 and 30 000 yr b p the timing of changes in the monsoon as established with 230th dates generally agrees with the timing of temperature changes from the greenland ice sheet project two gisp2 core which supports gisp2 s chronology in this interval our record links north atlantic climate with the meridional transport of heat and moisture from the warmest part of the ocean where the summer east asian monsoon originates

a high resolution absolute dated holocene and deglacial asian monsoon record from dongge cave china abstract we present a continuous record of the asian monsoon over the last 16 ka from 18o measurements of stalagmite calcite over 900 oxygen isotopic measurements providing information on shifts in monsoon precipitation are combined with a chronology from 45 precise 230th dates 18o and therefore asian monsoon intensity generally follows changes in insolation although changes in 18o are generally accommodated in abrupt shifts in contrast to smoothly varying insolation indicating that threshold effects may be important 18o decreased dramatically 3 at the start of the holocene 11 5 ka and remained low for 6 ka four positive 18o events centered at 11225 97 yr bp 1 05 10880 117 yr bp 1 15 9165 75 yr bp 1 4 and a double event centered at 8260 64 yr bp 1 1 and 8080 74 yr bp 1 0 punctuated this period of high monsoon intensity all four events correlate within error with climate changes in greenland ice cores thus the relationship between the asian monsoon and the north atlantic observed during the glacial period appears to continue into the early holocene in addition three of the four events correlate within error with outburst events from lake agassiz the decline of monsoon intensity in the mid late holocene is characterized by an abrupt positive shift in 18o which occurs at 3550 59 yr bp 1 1 in 100 yr in addition the holocene is punctuated by numerous centennial and multi decadal scale events amplitudes 0 5 to 1 up to half the amplitude of the glacial interstadial events seen in the last glacial period thus holocene centennial and multi decadal scale monsoon variability is significant although not as large as glacial millennial scale variability the monsoon shows a strong connection with northern south american hydrological changes related by changes in itcz position spectral analysis of the 18o record shows significant peaks at solar periodicities of 208 yr and 86 yr suggesting variation is influenced by solar forcing however there are numerous other significant peaks including peaks at el nino frequencies observed for high resolution portions of the record between 8110 and 8250 yr which suggest that changes in oceanic and atmospheric circulation patterns in addition to those forced by solar changes are important in controlling holocene monsoon climate in addition for this high resolution portion we observe a distinctive biennial oscillation of the asian monsoon which has been associated with the tropospheric biennial oscillation tbo

climate variability during the last 1000 years inferred from andean ice cores a review of methodology and recent results abstract andean ice core investigations began approximately 30 years ago today 10 drilling sites from 0 to 52 s have been explored for paleoclimate reconstructions most of the ice cores reaching the bedrock cover the last 20 000 years with seasonal resolution over the last few centuries to the last 1000 years for the quelccaya site we discuss both the potential and the limitations of tropical ice cores as climate archives with regard to the collaborative effort to reconstruct past climate variations in south america over the last 1000 years we point out the uniqueness of south american ice cores due to their location at high altitude and also their two main limitations which are related to i the interpretation of certain proxies in terms of climate and ii the relatively poor dating when seasonal cycles are no longer resolved in addition we present an overview of the proxies that have been used so far to analyze tropical climate dynamics finally we discuss records of enso the little ice age and the 20th century decadal variability including the anthropogenic period which are all preserved in ice cores

a strong control of the south american seesaw on the intra seasonal variability of the isotopic composition of precipitation in the bolivian andes water stable isotopes d in tropical regions are a valuable tool to study both convective processes and climate variability provided that local and remote controls on d are well known here we examine the intra seasonal variability of the event based isotopic composition of precipitation ddzongo in the bolivian andes zongo valley 16 20 s 67 47 w from september 1st 1999 to august 31st 2000 we show that the local amount effect is a very poor parameter to explain ddzongo we thus explore the property of water isotopes to integrate both temporal and spatial convective activities we first show that the local convective activity averaged over the 7 8days preceding the rainy event is an important control on ddzongo during the rainy season 40 of the ddzongo variability is captured this could be explained by the progressive depletion of local water vapor by unsaturated downdrafts of convective systems the exploration of remote convective controls on ddzongo shows a strong influence of the south american seesaw sass which is the first climate mode controlling the precipitation variability in tropical south america during austral summer our study clearly evidences that temporal and spatial controls are not fully independent as the 7 day averaged convection in the zongo valley responds to the sass our results are finally used to evaluate a water isotope enabled atmospheric general circulation model lmdz iso using the stretched grid functionality to run zoomed simulations over the entire south american continent 15 n 55 s 30 85 w we find that zoomed simulations capture the intra seasonal isotopic variation and its controls though with an overestimated local sensitivity and confirm the role of a remote control on d according to a sass like dipolar structure 2011 elsevier b v

increasing australian indonesian monsoon rainfall linked to early holocene sea level rise the australian indonesian summer monsoon affects rainfall variability across the indo pacific region reconstructions of monsoon strength from stalagmites show that precipitation increased from 11 000 to 7 000 years ago as rising global sea level caused the flooding of the indonesian continental shelf the australian indonesian summer monsoon affects rainfall variability and hence terrestrial productivity in the densely populated tropical indo pacific region it has been proposed that the main control of summer monsoon precipitation on millennial timescales is local insolation1 2 3 but unravelling the mechanisms that have influenced monsoon variability and teleconnections has proven difficult owing to the lack of high resolution records of past monsoon behaviour here we present a precisely dated reconstruction of monsoon rainfall over the past 12 000 years based on oxygen isotope measurements from two stalagmites collected in southeast indonesia we show that the summer monsoon precipitation increased during the younger dryas cooling event when atlantic meridional overturning circulation was relatively weak4 monsoon precipitation intensified even more rapidly from 11 000 to 7 000 years ago when the indonesian continental shelf was flooded by global sea level rise5 6 7 we suggest that the intensification during the younger dryas cooling was caused by enhanced winter monsoon outflow from asia and a related southward migration of the intertropical convergence zone8 however the early holocene intensification of monsoon precipitation was driven by sea level rise which increased the supply of moisture to the indonesian archipelago

stalagmite stable isotope record of recent tropical cyclone events we present a 23 yr stalagmite record 1977 2000 of oxygen isotope variation associated with 11 tropical cyclones tcs from actun tunichil muknal cave in central belize high resolution microsampling yielded a record of monthly to weekly temporal resolution that contains abrupt decreases negative excursions in calcite 18 o values that correspond with recent tc rain events nearby a logistic discriminant model reliably identifi ed tc proxy signals using the measurable parameters 18 o and 13 c values and single point changes in 18 o value the logistic model cor rectly identifi ed 80 of excursions as tc events and incorrectly classifi ed only 1 of nearly 1200 nonstorm sampling points in addition to enabling high resolution tc frequency reconstruction this geologic proxy also provides information about the intensity of individual tcs a multiple regression predicted tc intensity r 2 0 465 p 0 034 using sampling frequency and excursion amplitude consistent with previous low resolution studies we found that the decadal average 18 o value was lower during the 1990s when several tcs produced rainfall in the area but higher during the 1980s when only one tc struck longer accurately dated high resolution speleo them stable isotope records may be a useful new tool for paleotempestology to clarify associa tions between highly variable tc activity and the dynamic range of quaternary climate

in situ measurement of seasonal δ18o variations and analysis of isotopic trends in a modern speleothem from southwest australia we present a record of seasonal and inter annual oxygen o and carbon c isotope ratios from an 81 year old stalagmite from moondyne cave southwest australia the growth history of stalagmite mnd s1 is known since it grew on a cave boardwalk that was installed in 1911 and removed in 1992 this stalagmite provides an excellent test of speleothem climate proxies because the regional climate is strongly seasonal wet winter dry summer and has experienced a 200 mm 20 reduction of mean rainfall since the mid 1960s and a 0 8 c temperature rise since 1953 seasonal variations in calcite o were measured in situ by high spatial resolution ion microprobe whilst inter annual variations of o and c were measured by conventional gas source mass spectrometry comparison of the speleothem stable isotopes and instrumental temperature records reveals that o variations are too large to be driven by temperature alone and are in the opposite sense however daily rainfall o measurements show that the mean seasonal range in o of rainfall in southwest australia is large 2 and inversely correlated with rainfall amount a rainfall driver for the speleothem o is confirmed by the detection of seasonal shifts of 0 7 1 5 in speleothem that track rainfall o smoothed by storage in the overlying limestone the seasonal range in speleothem o is larger than any inter annual and decadal variation observed in the record the prominent annual cycles in speleothem o revealed by ion microprobe analysis indicate that subtle changes in the frequency of intense winter rainfall events or possibly also moisture sources could produce significant changes in mean speleothem o the ion microprobe results also raise the possibility that the masses of speleothem calcite deposited in winter and summer could vary as a function of the seasonal drip rate and carbonate saturation state of these waters if this is the case then small changes in the relative masses of calcite deposited in winter and summer could produce significant shifts in mean o and c that have a complex relation to climate this finding should be generally applicable to the interpretation of long term trends in speleothem geochemical records for shallow cave sites where seasonal variations in geochemical tracers are relatively large including most of the sub tropical monsoon belts and mid to high latitudes with distinct rainfall seasons