remote sensing estimates of glacier mass balances in the himachal pradesh western himalaya india abstract although they correspond to an important fraction of the total area of mountain glaciers 33 000 km2 out of 546 000 km2 himalayan glaciers and their mass balance are poorly sampled for example between 1977 and 1999 the average area surveyed each year on the field was 6 8 km2 only no direct mass balance measurement is available after 1999 to contribute to fill this gap we use remote sensing data to monitor glacier elevation changes and mass balances in the spiti lahaul region 32 2 n 77 6 e himachal pradesh western himalaya india our measurements are obtained by comparing a 2004 digital elevation model dem to the 2000 srtm shuttle radar topographic mission topography the 2004 dem is derived from two spot5 satellite optical images without any ground control points this is achieved thanks to the good on board geolocation of spot5 scenes and using srtm elevations as a reference on the ice free zones before comparison on glaciers the two dems are analyzed on the stable areas surrounding the glaciers where no elevation change is expected two different biases are detected a long wavelength bias affects the spot5 dem and is correlated to an anomaly in the roll of the spot5 satellite a bias is also observed as a function of altitude and is attributed to the srtm dataset both biases are modeled and removed to permit unbiased comparison of the two dem on the 915 km2 ice covered area digitized from an aster image on most glaciers a clear thinning is measured at low elevations even on debris covered tongues between 1999 and 2004 we obtain an overall specific mass balance of 0 7 to 0 85 m a water equivalent depending on the density we use for the lost or gained material in the accumulation zone this rate of ice loss is twice higher than the long term 1977 to 1999 mass balance record for himalaya indicating an increase in the pace of glacier wastage to assess whether these ice losses are size dependant all glaciers were classified into three samples according to their areal extent all three samples show ice loss the loss being higher for glaciers larger than 30 km2 in the case of the benchmark chhota shigri glacier a good agreement is found between our satellite observations and the mass balances measured on the field during hydrological years 2002 2003 and 2003 2004 future studies using a similar methodology could determine whether similar ice losses have occurred in other parts of the himalaya and may allow evaluation of the contribution of this mountain range to ongoing sea level rise

monitoring glacier variations on geladandong mountain central tibetan plateau from 1969 to 2002 using remote sensing and gis technologies using geographical information system gis and remote sensing technologies we describe quantitative measurements of glacier variations in the geladandong mountain region of central tibet data from landsat images at three different times 1973 76 1992 and 2002 are compared with glacier areas digitized from a topographic map based on aerial photographs taken in 1969 we find that while some glaciers have advanced during the past 30 years others have retreated the area of retreat is much larger than that of advance the total glacier area has decreased from 889 km 2 in 1969 to 847 km 2 in 2002 a reduction of almost 43 km 2 i e 4 8 decrease or an average of 1 29 km 2 a 1 the variation of glacier area in the geladandong mountain region is not as large as in other regions within the tibetan plateau glacier areas decreased 4 7 km 2 i e an average of 0 68 km 2 a 1 during 1969 76 15 4 km 2 0 96 km 2 a 1 during 1976 92 and 22 4 km 2 2 24 km 2 a 1 during 1992 2002 suggesting accelerated glacier retreat in recent years the recession rates of glacier termini also increased it is likely that the increase in summer air temperature is the major reason for glacier shrinkage in the geladandong mountain region

a penultimate glacial monsoon record from hulu cave and two phase glacial terminations oxygen isotope records of three stalagmites from hulu cave china extend the previous high resolution absolute dated hulu asian monsoon record from the last to the penultimate glacial and deglacial periods the penultimate glacial monsoon broadly follows orbitally induced insolation variations and is punctuated by at least 16 millennial scale events we confirm a weak monsoon interval between 135 5 1 0 and 129 0 1 0 ka prior to the abrupt increase in monsoon intensity at asian monsoon termination ii based on correlations with both marine ice rafted debris and atmospheric ch 4 records we demonstrate that most of marine termination ii the full rise in antarctic temperature and atmospheric co 2 and much of the rise in ch 4 occurred within the weak monsoon interval when the high northern latitudes were probably cold from these relationships and similar relationships observed for termination i we identify a two phase glacial termination process that was probably driven by orbital forcing in both hemispheres affecting the atmospheric hydrological cycle and combined with ice sheet dynamics

glacier shrinkage in the ebinur lake basin tien shan china during the past 40 years the ebinur lake basin tien shan china was described in the early 20th century as the green labyrinth this relatively productive area supports agriculture and stands in contrast to the regional aridity glacier melt runoff is an important source of water for this arid region and has played a significant role in its economic development however over the past 40 years the ecology and environment of the region have seriously degenerated due to human activity and climate change to investigate changes in glacier water supply measurements from two reference glaciers were performed and used to validate satellite data and historical data for glaciers in the water catchment variability in regional glacier total area and volume over the past 40 years was reconstructed from historical documents aerial photographs and remote sensing data our investigations of 446 glaciers showed that from 1964 to 2004 the total glacier area decreased by 14 7 0 4 a 1 corresponding to an estimated volume change of 20 5 during this period the most dramatic decrease in glacier area corresponded to a rapid rise in temperature this reduction in glacier area is accelerating and impacting the future sustainability of the region s water resources

hydrological regimes under the conjunction of westerly and monsoon climates a case investigation in the astore basin northwestern himalaya in a changing climate river basins with limited summer precipitation but abundant snow and glacier melt water are affected severely by reductions and seasonal alterations in annual stream flows however high altitude glacio hydrological observations and investigations to address the linkage between the timing of glacier changes and river runoff fluctuations remain ambiguous particularly in the northwestern himalayan region of pakistan in this context the hydrological regime of the astore basin a sub catchment of the upper indus river basin was comprehensively investigated by employing in situ hydro meteorological observations in combination with satellite remote sensing data two thirds of the annual precipitation in the astore basin falls in winter and spring mainly deposited by westerly winds whereas summer and autumn precipitation deposited by the monsoon and local jet streams accounts for only one third some 14 of the basin area is covered by glaciers and added to the accumulated seasonal snow deposited by westerly circulations this can reach 80 85 of the basin area therefore more than 75 of the annual basin runoff depends on melt water produced by the predominant seasonal snow and glacier ablation the non parametric mann kendall trend test was applied to the whole time series of hydro meteorological data this indicated a lowering of annual and summer mean temperatures during the period 1980 1995 and slight warming during the 1996 2010 period similarly annual winter and summer precipitation and annual mean discharge increased from 1980 to 1995 but in contrast a slight decrease in annual and summer precipitation was observed during the 1996 2010 period however discharge evidence is slight making any increase in this period insignificant in addition the spearman and mann kendall correlation results depict annual stream flow fluctuations during the 1980 2010 decades in the astore river that were predominantly influenced by precipitation variations but not by any alteration in catchment temperatures and so not governed by enhanced glacier ablation and retreat the results of the analysis presented here were also substantiated by satellite remote sensing investigation which points to evidence of stable conditions in the astore basin glaciers during this period

quantification of holocene asian monsoon rainfall from spatially separated cave records abstract a reconstruction of holocene rainfall is presented for southwest china an area prone to drought and flooding due to variability in the east asian monsoon the reconstruction is derived by comparing a new high resolution stalagmite 18 o record with an existing record from the same moisture transport pathway the new record is from heshang cave 30 27 n 110 25 e 294 m and shows no sign of kinetic or evaporative effects so can be reliably interpreted as a record of local rainfall composition and temperature heshang lies 600 km downwind from dongge cave which has a published high resolution 18 o record wang y j cheng h edwards r l he y q kong x g an z s wu j y kelly m j dykoski c a li x d 2005 the holocene asian monsoon links to solar changes and north atlantic climate science 308 854 857 by differencing co eval 18 o values for the two caves secondary controls on 18 o e g moisture source moisture transport non local rainfall temperature are circumvented and the resulting 18 o signal is controlled directly by the amount of rain falling between the two sites this is confirmed by comparison with rainfall data from the instrumental record which also allows a calibration of the 18 o proxy the calibrated 18 o record provides a quantitative history of rainfall in southwest china which demonstrates that rainfall was 8 higher than today during the holocene climatic optimum 6 ka but only 3 higher during the early holocene significant multi centennial variability also occurred with notable dry periods at 8 2 ka 4 8 4 1 ka 3 7 3 1 ka 1 4 1 0 ka and during the little ice age this holocene rainfall record provides a good target with which to test climate models the approach used here of combining stalagmite records from more than one location will also allow quantification of rainfall patterns for past times in other regions

the east asian monsoon during mis 2 expressed in a speleothem δ18o record from jintanwan cave hunan china abstract stalagmite j1 from jintanwan cave hunan china provides a precisely dated decadally resolved 18o proxy record of paleoclimatic changes associated with the east asian monsoon from 29 5 to 14 7 ka and from 12 9 to 11 0 ka at the time of the last glacial maximum lgm the east asian summer monsoon weakened and then strengthened in response to changes in northern hemisphere insolation as the ice sheets retreated the east asian summer monsoon weakened especially during heinrich event h1 when atmospheric and oceanic teleconnections transferred the climatic changes around the north atlantic to the monsoonal regions of eastern asia a depositional hiatus between 14 7 and 12 9 ka leaves the deglacial record incomplete but an abrupt shift in 18o values at 11 5 ka marks the end of the younger dryas and the transition into the holocene comparisons of the j1 record to other chinese speleothem records indicate synchronous climatic changes throughout monsoonal china further comparisons to a speleothem record from western asia socotra island and to greenland ice cores support hemispherical scale paleoclimatic change spectral and wavelet analyses reveal centennial and decadal scale periodicities that correspond to solar frequencies and to oscillations in atmospheric and oceanic circulation

the nature origin and significance of luminescent layers in the bazhenov shale formation of west siberia russia abstract argillites that strongly luminesce under uv radiation were detected in the bazhenov shale formation bsf of the west siberian basin during routine core examination and found to be persistent over a wide lateral area the mineralogy and fabric of these luminescent layers were characterized by optical and fluorescence microscopy sem tem xrd and ir methods optical and fluorescence microscopy showed that the luminescent layers were to a large extent derived from volcanic ash falls and could be described as meta tuffites although normal detrital sedimentation continued at the same time the layers have a thickness of several mm to a maximum of 3 4 cm and can be defined as a clay rich regional horizons extending for over 500 km xrd showed that two principal clay minerals were predominant namely a kaolinite group minerals kaolinite rich and a mixed layer illite smectite i s similar to that found in k bentonite total organic matter in the luminescent layers is much lower than that in the enclosing bsf clayey silty siliceous sediments above and below as shown by pyrolytic analyses evidence is presented that the luminescent characteristic of the argillites is related to their clay mineralogy specifically to their content of kaolin minerals although a contribution from nitrogenous organic matter cannot be entirely discounted in some ways the luminescent argillites can be compared with bentonites associated with ash transformations or with tonsteins in coal beds which are also derived from volcanic ash falls and contain highly crystalline kaolinite however tonsteins originate at or near land surface whereas the argillites were apparently formed in the deep ocean but just as tonsteins can be used for detailed stratigraphic studies and are valuable in the context of coal exploration so may the luminescent argillites prove to be significant both stratigraphically and in the search for economic hydrocarbon deposits bearing in mind that their clay mineralogy may be sensitive to temperature and depth of burial and related to their placement in the oil and gas window

composition and formation environments of the upper jurassic lower cretaceous black shale bazhenov formation the central part of the west siberian basin most researchers consider the black shale bazhenov formation as the main source of petroleum in the west siberian fields detailed sedimentological mineralogical and geochemical investigations reveal that there are three main types of bazhenov formation rocks i clayey siliceous ii argillites and iii anomalous clayey silt sandy rocks the first type is characterized by more frequent benthic and planktonic fossils extreme reducing conditions and lower rates of sedimentation in comparison with the argillites the clayey silt sandy anomalous rocks are non fossiliferous were deposited in oxic conditions and are characterized by the highest rates of sedimentation we conclude that the clayey siliceous rocks were deposited in moderately hemipelagic environments the argillites were products of distal turbidities and the anomalous clayey silt sandy rocks were deposited in channels

on the accuracy of glacier outlines derived from remote sensing data deriving glacier outlines from satellite data has become increasingly popular in the past decade in particular when glacier outlines are used as a base for change assessment it is important to know how accurate they are calculating the accuracy correctly is challenging as appropriate reference data e g from higher resolution sensors are seldom available moreover after the required manual correction of the raw outlines e g for debris cover such a comparison would only reveal the accuracy of the analyst rather than of the algorithm applied here we compare outlines for clean and debris covered glaciers as derived from single and multiple digitizing by different or the same analysts on very high 1 m and medium resolution 30 m remote sensing data against each other and to glacier outlines derived from automated classification of landsat thematic mapper data results show a high variability in the interpretation of debris covered glacier parts largely independent of the spatial resolution area differences were up to 30 and an overall good agreement for clean ice with sufficient contrast to the surrounding terrain differences 5 the differences of the automatically derived outlines from a reference value are as small as the standard deviation of the manual digitizations from several analysts based on these results we conclude that automated mapping of clean ice is preferable to manual digitization and recommend using the latter method only for required corrections of incorrectly mapped glacier parts e g debris cover shadow

challenges and recommendations in mapping of glacier parameters from space results of the 2008 global land ice measurements from space glims workshop boulder colorado usa on 16 18 june 2008 the us national snow and ice data center held a glims workshop in boulder co usa focusing on formulating procedures and best practices for operational glacier mapping using satellite imagery despite the progress made in recent years there still remain many cases where automatic delineation of glacier boundaries in satellite imagery is difficult error prone or time consuming this workshop identified six themes for consideration by focus groups 1 mapping clean ice and lakes 2 mapping ice divides 3 mapping debris covered glaciers 4 assessing changes in glacier area and elevation through comparisons with older data 5 digital elevation model dem generation from satellite stereo pairs and 6 accuracy and error analysis talks presented examples and work in progress for each of these topics and focus groups worked on compiling a summary of available algorithms and procedures to address and avoid identified hurdles special emphasis was given to establishing standard protocols for glacier delineation and analysis creating illustrated tutorials and providing source code for available methods this paper summarizes the major results of the 2008 glims workshop with an emphasis on definitions methods and recommendations for satellite data processing while the list of proposed methods and recommendations is not comprehensive and is still a work in progress our goal here is to provide a starting point for the glims regional centers as well as for the wider glaciological community in terms of documentation on possible pitfalls along with potential solutions

characterization of recent glacier decline in the cordillera real by landsat alos and aster data the changing sizes of glaciers in the cordillera real 16 2 s 68 2 w bolivian andes between 1987 and 2010 were determined by a band ratio method using cloud free landsat tm and alos avnir 2 data from 1987 to 2010 glacier covered areas in the cordillera real were found to have diminished by more than 30 the rate of glacierized area shrinkage within this andean region and particularly of its glaciers has significantly increased in the past 5 years to characterize the change in glacierized area a changing factor k was introduced to capture the effects of topographic factors including elevation slope angle and aspect as identified using aster 30 m global dem data on the huayna potosi mururata charquini illimani and serkhe khollu glaciers this study also further analyzed the huayna potosi glacier and discussed the inhomogeneity of changes in its area with elevation slope aspect and the distribution of solar radiation

contrasting patterns of early twenty first century glacier mass change in the himalayas glaciers are among the best terrestrial climate indicators an important water resource in mountains1 2 and a major contributor to global sea level rise3 4 in the hindu kush karakoram himalaya region hkkh a paucity of appropriate glacier data has prevented a comprehensive assessment of current regional mass balance5 however there are indirect evidences of a complex pattern of glacial responses5 8 in reaction to heterogeneous climate change signals9 here we provide the first coherent data set of detailed glacier thickness changes over the hkkh during 2003 2009 by combining satellite laser altimetry and a global elevation model in the eastern central and south western parts of the hkkh glacier wastage is widespread with regional thinning rates up to 0 66 0 09 m a 1 in the jammu kashmir region conversely in the karakoram glaciers are close to balance with only a slight thinning of 0 07 0 04 m a 1 regionally averaged thinning rates under debris mantled ice are similar to those of clean ice despite insulation by debris covers the 2003 2008 specific mass balance for our hkkh study region is 0 21 0 05 m a 1 water equivalent we significantly less negative than the global average of 0 7 m a 1 we for glaciers and ice caps4 10 this difference is mainly an effect of the balanced glacier mass budget in the karakoram the corresponding hkkh sea level contribution is 0 035 0 009 mm a 1 amounting to 1 of the present day sea level rise11 our 2003 2008 mass budget of 12 8 3 5 gt a 1 is more negative than recent satellite gravimetry based estimates of 5 6 gt a 1 over 2003 2010 ref 12 for the mountain catchments of the indus and ganges basins13 the glacier imbalance contributes 3 5 and 2 0 respectively to the annual average river discharge13 and up to 10 for the upper indus basin14

millennial scale variability in the asian monsoon evidence from oxygen isotope records from stalagmites in southeastern china abstract two stalagmites from xiangshui x3 and yaoba don yb1 caves in southeastern china provide high resolution 18o time series that exhibit prominent millennial scale fluctuations in the intensity and character of the asian monsoon for the period from 20 000 to 50 000 yr b p timing of these fluctuations established by u series disequilibrium 230th 234u correlates with dansgaard oeschger events 2 13 and heinrich events h2 h5 recorded in the gisp2 ice core indicating a climatic link between asian monsoon circulation and air temperatures over the north atlantic for much of the last glaciation although the exact mechanisms linking climatic fluctuations in the north atlantic to those in eastern china have yet to be identified climatic signals associated with changes in global ice volume and air temperatures over greenland may be transferred to asia by atmospheric mechanisms that affect the strength of the siberian high pressure cell and the amount of snow cover on the tibetan plateau which force the intensity of the asian monsoon another mechanism linking climate of the north atlantic to the asian monsoon relates to variation in oceanic circulation millennial scale fluctuations in thermohaline circulation in the north atlantic may have affected ocean currents in the tropical western pacific ocean which is the moisture source for the east asian monsoon despite the similarity of these paleoclimatic records and the implication of global teleconnections the magnitude and timing of millennial scale events at different locations in china reveal regional variations in climatic conditions comparisons of the 18o curves from xiangshui and yaoba don cave stalagmites with those from qixin cave and hulu cave show general concordance between millennial scale events albeit with some notable differences among all the records the well studied hulu cave records show 18o values that are lower than those of xiangshui and yaoba don caves reflecting geographical differences hulu cave is located near the eastern coast at a relatively low elevation dominated by the east asian monsoon by comparison xiangshui cave and yaoba don cave are further inland on the eastern slope of the yunnan guizhou plateau which receives precipitation from both the east asian monsoon and quasi stationary frontal systems rainfall contributed by the east asian summer monsoon is relatively diminished in this region by these geographic and atmospheric circulation conditions resulting in higher 18o values

response of debris covered glaciers in the mount everest region to recent warming and implications for outburst flood hazards abstract in areas of high relief many glaciers have extensive covers of supraglacial debris in their ablation zones which alters both rates and spatial patterns of melting with important consequences for glacier response to climate change wastage of debris covered glaciers can be associated with the formation of large moraine dammed lakes posing risk of glacier lake outburst floods glofs in this paper we use observations of glaciers in the mount everest region to present an integrated view of debris covered glacier response to climate change which helps provide a long term perspective on evolving glof risks in recent decades debris covered glaciers in the everest region have been losing mass at a mean rate of 0 32 m yr 1 although in most cases there has been little or no change in terminus position mass loss occurs by 4 main processes 1 melting of clean ice close to glacier elas 2 melting beneath surface debris 3 melting of ice cliffs and calving around the margins of supraglacial ponds and 4 calving into deep proglacial lakes modelling of processes 1 and 2 shows that everest region glaciers typically have an inverted ablation gradient in their lower reaches due to the effects of a down glacier increase in debris thickness mass loss is therefore focused in the mid parts of glacier ablation zones causing localised surface lowering and a reduction in downglacier surface gradient which in turn reduce driving stress and glacier velocity so the lower ablation zones of many glaciers are now stagnant model results also indicate that increased summer temperatures have raised the altitude of the rain snow transition during the summer monsoon period reducing snow accumulation and ice flux to lower elevations as downwasting proceeds formerly efficient supraglacial and englacial drainage networks are broken up and supraglacial lakes form in hollows on the glacier surface ablation rates around supraglacial lakes are typically one or two orders of magnitude greater than sub debris melt rates so extensive lake formation accelerates overall rates of ice loss most supraglacial lakes are perched above hydrological base level and are susceptible to drainage if they become connected to the englacial drainage system speleological surveys of conduits show that large englacial voids can be created by drainage of warm lake waters along pre existing weaknesses in the ice roof collapses can open these voids up to the surface and commonly provide the nuclei of new lakes thus by influencing both lake drainage and formation englacial conduits exert a strong control on surface ablation rates an important threshold is crossed when downwasting glacier surfaces intersect the hydrological base level of the glacier base level lakes formed behind intact moraine dams can grow monotonically and in some cases can pose serious glof hazards glacier termini can evolve in different ways in response to the same climatic forcing so that potentially hazardous lakes will form in some situations but not others additionally the probability of a flood is not simply a function of lake volume but depends on the geometry and structure of the dam and possible trigger mechanisms such as ice or rockfalls into the lake satellite based measurements of glacier surface gradient and ice velocities allow probable future locations of base level lakes to be identified a base level lake has begun to grow rapidly on ngozumpa glacier west of mount everest and could attain a volume of 10 8 m 3 within the next 2 or 3 decades unless mitigation efforts are undertaken this lake could pose considerable glof hazard potential

estimation of lakes water storage and their changes on the northwestern tibetan plateau based on bathymetric and landsat data and driving force analyses abstract lake water storage changes in four lakes were analyzed based on in situ bathymetric survey data and landsat images in the extremely dry and cold northwestern tibetan plateau region the results indicated that bangdag co and aksai chin lake which are glacier fed and closed lakes showed decreasing trends from 1976 to 1996 then increasing trend from 1996 to 2015 during which period water storage increased by 1 24 km3 and 1 37 km3 respectively and 65 of the water storage increase in aksai chin lake during this period occurring in 2006 and 2013 longmu co which is a non glacier fed lake exhibited little variation from 1976 to 1996 and a slight increase of 0 1 km3 from 1996 to 2015 the precipitation temperature and potential evaporation ep trends indicated that lake shrinkage from 1976 to 1996 was attributed to less precipitation and less meltwater at lower surface air temperatures decreased ep 15 5 mm y contributed approximately 2 and 4 to the lake expansion of aksai chin lake and bangdag co from 2000 to 2009 based on the assumption of equal precipitation evaporation for the study area glacial meltwater contributed 76 6 to the lake expansion of bangdag co from 2000 to 2015 because change in lakes water storage showed a large difference between glacier fed lakes and non glacier fed lakes from 1996 to 2015 under relatively high precipitation conditions it is suggested that glacial meltwater exerted more influence on increasing lake water storage associated with rising temperatures

holocene stalagmite δ18o records in the east asian monsoon region and their correlation with those in the indian monsoon region we compare well dated holocene stalagmite delta o 18 records from the east asian summer monsoon easm region and from the indian summer monsoon ism region we found that the pattern of latitudinal change of speleothem delta o 18 values from the indian monsoon region to the east asian monsoon region is almost identical to that of modern precipitation this suggests that the modern moisture transport route from the indian ocean to the east asian monsoon region has existed since at least the early holocene the delta o 18 records from both regions exhibit a remarkably similar trend of variation in that the values are more negative during the early holocene rapidly become heavy from the mid holocene and are heaviest during the late holocene the stalagmite delta o 18 changes in the east asian monsoon region are statistically well correlated with those in the indian monsoon region both over the entire holocene and in detail over the last 2000 years however in contrast to the obvious consistency of the delta o 18 values in all of the speleothem records both instrumental and historical climate records indicate significant spatial variations in rainfall over eastern china the early holocene strong easm pattern referred from speleothem delta o 18 in the east asian monsoon region is quite different to that of other paleoclimatic records such as holocene paleosol development in the chinese loess plateau eolian activity in the northern chinese sandlands and lake sediments in easm dominated region in china in which the strongest easm was documented during the mid holocene these findings suggest that the speleothem delta o 18 record from the east asian monsoon region may not record easm variability but rather that it is controlled by variations in the isotopic composition of precipitation which is determined mainly by rainfall variability in the ism region

spatially variable response of himalayan glaciers to climate change affected by debris cover the present state and future evolution of himalayan glaciers has been controversial an analysis of remotely sensed frontal changes and surface velocities from glaciers in the greater himalaya between 2000 and 2008 shows large regional variability in the responses of himalayan glaciers to climate change

seasonal variability of oxygen and hydrogen stable isotopes in precipitation and cave drip water at guilin southwest china the interpretation of climatic information from stalagmites has traditionally been a complex research problem with oxygen isotopes playing a particularly important role in global climate change studies this study investigates the relationship between oxygen isotope composition of the atmospheric in precipitation and cave drip water at panlong cave in southwest china on seasonal timescales of variability time series seasonal variability was derived from panlong cave in guilin by collecting daily precipitation samples for stable isotope analysis during 2012 results indicate that 18o of precipitation contains a clear seasonal variation whereby higher values are mainly distributed during winter and lower values during summer seasonal variations in water sources affect the precipitation 18o values drip water 18o also displayed a seasonal cycle which is attenuated relative to 18o of precipitation drip water time series display seasonal cycle ranges from 1 5 to 3 5 relative to vienna standard mean ocean water which mainly follow the precipitation 18o seasonal cycle seasonal variation in drip water 18o supports interpretations of the stalagmite 18o record as a paleoclimate proxy sensitive to the local environment this monitoring experiment revealed that drip water must be transported through the epikarst in approximately 1 5 months during cold periods and 0 5 months during warm periods different residence time percolation is mainly affected by the atmospheric precipitation amount depending on whether soil moisture reaches saturation

spatial and temporal variability in the stable isotope systematics of modern precipitation in china implications for paleoclimate reconstructions the stable isotopic composition of materials such as glacial ice tree rings lake sediments and speleothems from low to mid latitudes contains information about past changes in temperature t and precipitation amount p however the transfer functions which link 18op to changes in t or p d 18op dt and d 18op dp can exhibit significant temporal and spatial variability in these regions in areas affected by the southeast asian monsoon past variations in 18o and d of precipitation have been attributed to variations in monsoon intensity storm tracks and or variations in temperature proper interpretation of past 18op variations here requires an understanding of these complicated stable isotope systematics since temperature and precipitation are positively correlated in china and have opposite effects on 18op it is necessary to determine which of these effects is dominant for a specific region in order to perform even qualitative paleoclimate reconstructions here we evaluate the value of the transfer functions in modern precipitation to more accurately interpret the paleorecord the strength of these transfer functions in china is investigated using multiple regression analysis of data from 10 sites within the global network for isotopes in precipitation gnip 18op is modeled as a function of both temperature and precipitation the magnitude and signs of the transfer functions at any given site are closely related to the degree of summer monsoon influence 18op values at sites with intense summer monsoon precipitation are more dependent on the amount of precipitation than on temperature and therefore exhibit more negative values in the summer in contrast 18op values at sites that are unaffected by summer monsoon precipitation exhibit strong relationships between 18op and temperature the sites that are near the northern limit of the summer monsoon exhibit dependence on both temperature and amount of precipitation comparison with simple linear models 18op as a function of t or p and a geographic model 18op as a function of latitude and altitude shows that the multiple regression model is more successful at reproducing 18op values at sites that are strongly influenced by the summer monsoon the fact that the transfer function values are highly spatially variable and closely related to the degree of summer monsoon influence suggests that these values may also vary temporally since the southeast asian monsoon intensity is known to exhibit large variations on a number of timescales annual to glacial interglacial and the magnitude and sign of the transfer functions is related to monsoon intensity we suggest that as monsoon intensity changes the magnitude and possibly even the sign of the transfer functions may vary therefore quantitative paleoclimate reconstructions based on 18op variations may not be valid

the transfer of seasonal isotopic variability between precipitation and drip water at eight caves in the monsoon regions of china abstract this study presents new stable isotope data for precipitation 18op and drip water 18od from eight cave sites in the monsoon regions of china mrc with monthly to bi monthly sampling intervals from may 2011 to april 2014 to investigate the regional scale climate forcing on 18op and how the isotopic signals are transmitted to various drip sites the monthly 18op values show negative correlation with surface air temperature at all the cave sites except shihua cave which is opposite to that expected from the temperature effect in addition although the monthly 18op values are negatively correlated with precipitation at all the cave sites only three sites are significant at the 95 level these indicate that due to the various vapor sources a large portion of variability in 18op in the mrc cannot be explained simply by either temperature or precipitation alone all the thirty four drip sites are classified into three types based on the 18od variability about 82 of them are static drips with little discernable variation in 18od through the whole study period but the drip rates of these drips are not necessary constant their discharge modes are site specific and the oxygen isotopic composition of the stalagmites growing from them may record the average of multi year climatic signals which are modulated by the seasonality of recharge and potential effects of evaporation and in some cases infiltration from large rainfall events about 12 of the thirty four drip sites are seasonal drips although the amplitude of 18od is narrower than that of 18op the monthly response of 18od to coeval precipitation is not completely damped and some of them follow the seasonal trend of 18op very well these drips may be mainly recharged by present day precipitation mixing with some stored water thus the stalagmites growing under them may record portions of the seasonal climatic signals embedded in 18op about 6 of the thirty four drip sites are medium variability drips with constant and relatively low 18od values in the wet season but with variable and relatively high 18od values in the dry season reflecting flow switching in the karst or evaporation inside the cave

the δ18o and δ13c records in an aragonite stalagmite from furong cave chongqing china a 2000 year record of monsoonal climate abstract a 7 cm long aragonite stalagmite fr0510 1 from furong cave chongqing was dated by 210pb and 230th methods revealing a 2000 year record of climate history under the influence of the east asian monsoon the fr0510 1 record resembles dongge cave da record on 10 100 year scales but quite different from the wanxiang cave wx42b record indicating that while stalagmite 18o record represents local regional moisture change spatial variability of the monsoonal rainfall over eastern china must take into account during the past 2000 years climate in chongqing was relatively wet in the intervals of 50 bc ad 250 ad 1150 1450 and ad 1600 1950 and relatively dry during the periods of ad 250 1150 and ad 1450 1600 dry conditions were prevailing over the medieval warm period whereas wet climates were dominant during the most time of the little ice age in chongqing area

evolution of the west siberian basin the west siberian basin is one of the largest intracratonic basins of the world and an important hydrocarbon province of russia perhaps the most important geologic event in siberia was the emplacement of basalts around 250 ma i e permo triassic boundary covering an area of about 5 10 6 km 2 this volcanism may be responsible for a mass extinction that occurred around permian triassic time the prebasaltic rifting event was limited to the north northeastern sector of the basin initial basin wide subsidence took place in the jurassic as a result of which the western part of siberia became the west siberian basin bounded by uplifts to the east and to the west one of the surprising aspects of the west siberian basin is the abundance of subvertical faults believed to be result of strike slip movement while intraplate inversions and fault reactivation structures have been observed in many cratons subvertical faults observed in the west siberian basin are unique because of their geometries and abundance the differentiation between the effects of tectonics and eustasy in cratonic basins is simple the global eustatic signal is basin wide with regional and local tectonics playing an overprinting role thus the middle jurassic turonian first second and third order cycles in the west siberian basin were primarily driven by eustasy the middle jurassic turonian series can be subdivided into two second order and 16 third order transgressive regressive cycles within dataset extent fourth order cycles appear to be controlled by delta shifting although extensively studied a number of fundamental questions regarding the origin and evolution of the west siberian basin remain unresolved or poorly documented in the literature

glacier change in the poiqu river basin inferred from landsat data from 1975 to 2010 abstract the poiqu river basin is a transboundary basin that is highly prone to glacial lake outburst floods this basin is located in the middle of the himalayas between china and nepal fieldwork investigating nearby glaciers has indicated that glaciers in this region have ablated quickly in recent decades a new glacier database for the poiqu river basin was generated for the phases 1975 2000 and 2010 using automatic classification and manual visual interpretation based on long time series landsat data in 2010 the poiqu river basin had 124 glaciers with a total area of 203 4 5 3 km 2 eleven glaciers have debris covered tongues with the debris covering a total area of 51 0 1 5 km 2 during the period of 1975 2000 the area change rates of all glaciers in the basin clean ice and debris covered parts were 0 45 y 0 71 y and 0 96 y respectively from 2000 to 2010 these area change rates were 0 82 y 1 24 y and 0 73 y respectively the number of glaciers and area change of clean ice within various size classes indicate that the large glaciers shrink into small glaciers and smaller glaciers retreated faster the mean size of the glaciers in this basin is within the size class 1 0 5 0 km 2 the area change rate for 1 0 5 0 km 2 glaciers was similar to that of all glaciers in the poiqu river basin the altitude of the region with the fastest change rfc uplifted from 5200 m to 5500 m and the area change rate of glaciers in the rfc accelerated from 0 17 km 2 y to 0 21 km 2 y between the two periods 1975 to 2000 and 2000 to 2010 aspect analysis indicates that for a long time period glaciers with southward aspects including south east southeast and southwest in the poiqu river basin retreated faster than glaciers with northward aspects including west north northeast and northwest at the decade scale changes in areas of glaciers were more influenced by composition than aspect additionally the retreat rate of the glaciers in the poiqu river is in a state of accelerating ablation since 2000 despite elevation and aspect

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

recommendations for the compilation of glacier inventory data from digital sources modern geoinformatic techniques allow the automated creation of detailed glacier inventory data from glacier outlines and digital terrain models dtms once glacier entities are defined and an appropriate dtm is available several methods exist to derive the inventory data e g minimum maximum and mean elevation mean slope and aspect for each glacier from digital intersection of both datasets compared to the former manual methods the new grid based statistical calculations are very fast and reproducible the major aim of this contribution is to help in standardizing the related calculations to enhance the integrity of the global land ice monitoring from space glims database the recommendations were prepared by a working group and also contribute to the european space agency project globglacier the document follows the former unesco manual for the production of the world glacier inventory published in 1970 identifies the potential pitfalls and describes the differences from the former methods of compilation the online background material for this paper see http www glims org contains example scripts for calculation of each parameter and will be updated when required

fractionation of azaarenes during oil migration abstract a comparative study of alkylbenzoquinolines in crude oils and rock extracts bitumens from japan and sumatra shows that the ratios of nitrogen masked isomers nmis to nitrogen exposed isomers neis and the ratio of higher homologs to lower homologs is higher in crude oils than in corresponding bitumens also a regular increase in the ratios of nmis to neis with increasing migration distance is observed for a series of crude oils from the sarukawa oil field northeastern japan these results are attributed to the preferential migration of nmis caused by their weak adsorption on clay minerals and or their low solubility in interstitial water and the selective removal of lower honologs caused by their irreversible adsorption onto clays during oil migration which are regarded as geochromatographic phenomena it is suggested that those ratios can be used to estimate the degree of fractionation of oils during primary and secondary migration

seasonal variations of deuterium and oxygen 18 isotopes and their response to moisture source for precipitation events in the subtropical monsoon region deuterium and oxygen 18 are common environmental tracers in water used to investigate hydrological processes such as evaporation and groundwater recharge and to trace moisture source in this study we collected event precipitation from 01 january 2010 to 28 february 2011 at a site in changsha yangtze river basin to estimate the influence of moisture source and atmospheric conditions on stable isotope compositions the local meteoric water line established as d 8 45 0 13 18o 17 7 0 9 r2 0 97 n 189 had a higher slope and intercept than global meteoric water line temperature 18o exhibited complex correlations with positive correlations during nov apr superior to during jun sep which was attributed to distinctive moisture sources but vague the overall period amount effect examined throughout the year linear regressions between 18o and d value in different precipitation event size classes revealed progressively decreasing slope and intercept values with decreasing precipitation amount and increasing vapour pressure deficit indicating that small rainfall events 0 5 mm were subject to secondary evaporation effects during rainwater descent in contrast snowfall and heavy precipitation events exhibited high slope and intercepts for the regression equation between 18o and d high concentrations of heavy isotopes were associated with precipitation events sourced from remote westerly air masses degenerated tropical marine air masses from the bay of bengal bob and inland moisture in the pre monsoon period as determined from backward trajectories assessed in the hysplit model meanwhile low concentrations of heavy isotopes were found to correspond with remote maritime moisture from bob the south china sea and the west pacific at three different air pressures in summer monsoon and post monsoon using hysplit and records of typhoon paths these findings suggest that stable isotope compositions in precipitation events are closely associated with the meteorological conditions and respond sensitively to moisture source in subtropical monsoon climates copyright 2013 john wiley sons ltd

changes in the glacier extent and surface elevation along the ningchan and shuiguan river source eastern qilian mountains china we investigate the changes at nine glaciers in the ningchan and shuiguan river source eastern qilian mountains between 1972 and 2010 according to analysis of topographic maps and multispectral satellite data all nine glaciers in the study area have retreated by a maximum of 250 57 4 m and a minimum of 91 57 4 m the total glacier area decreased by 1 20 km 2 corresponding to 9 9 of the glacierized area in 1972 comparing the two dems generated from the topographic maps and real time kinematic gps data the mean glacier thinning rate was 0 64 m yr 1 between 1972 and 2010 the most significant thinning generally occurred on the termini the ice volume loss was about 106 8 46 7 x 10 3 km 3 equal to 90 8 39 7 x 10 3 km 3 w e which suggested a mean water discharge of 0 1 0 05 m 3 s during 1972 2010 based on analysis of meteorological data the summer temperature june august tends to increase over a similar time period the consistency of temperature increase and glacier shrinkage allows us to suggest that air temperature plays an important role in glacier changes in this region c 2014 university of washington published by elsevier inc all rights reserved

δ18o characteristics of meteoric precipitation and its water vapor sources in the guilin area of china the stable isotopic composition of meteoric precipitation is an important component of global and regional water cycle research stable isotope data can help reconstruct paleoclimate related to ice cores lake sediments and stalagmites we investigated the daily variation in isotopic composition of meteoric precipitation from 2008 to 2012 in the guilin region of china 18o of meteoric precipitation ranged from 14 21 to 2 38 with an average value of 5 78 vienna standard mean ocean water vsmow meteoric precipitation in the summer half year may through october increased with a relatively low 18o value of 8 04 vsmow average of 261 groups and 56 03 vsmow of average d accounting for 67 6 of the total annual meteoric precipitation meteoric precipitation in the winter half year november through april decreased with a relatively high 18o value of 2 89 average of 210 groups and 9 23 of average d accounting for 32 4 of total meteoric precipitation the local meteoric water line lmwl equation in guilin area has local climate characteristics by combining environmental isotope data of precipitation using a backwards trajectory water vapor sources of the meteoric precipitation in guilin area are inferred and traced our results show that the isotopic composition of meteoric water vapor sources in guilin area are related to monsoon type source of precipitation cloud masses and precipitation properties the isotopic composition of meteoric precipitation in the summer half year may through october was mainly affected by the summer monsoon or summer typhoons namely controlled by water vapor source from the bay of bengal and the south china sea and the second the west pacific and the 18o value of meteoric precipitation was strongly negative there was a significant negative correlation between the 18o values of meteoric precipitation and the amount of precipitation and temperature in the summer half year the amount effect of the meteoric precipitation often concealed the temperature effect the isotopic composition of meteoric precipitation in the winter season or winter half year was affected by the water vapor source of the warm moist air masses from the west pacific and continental cold air masses from the siberia mongolia winter monsoon or local evaporation vapor circulation and the 18o value of meteoric precipitation was relatively positive and indicated that the water vapor of meteoric precipitation along the water vapor trajectory was affected by the evaporation as well as the local water vapor evaporation the research results have showed that different sources of water vapor has a significant influence on the 18o variation of meteoric precipitation therefore analysis of 18o in the meteoric precipitation especially its seasonal variation characteristics of analysis can conversely reveal the water vapor sources of local meteoric precipitation

k bentonites a review pyroclastic material in the form of altered volcanic ash or tephra has been reported and described from one or more stratigraphic units from the proterozoic to the tertiary this altered tephra variously called bentonite or k bentonite or tonstein depending on the degree of alteration and chemical composition is often linked to large explosive volcanic eruptions that have occurred repeatedly in the past k bentonite and bentonite layers are the key components of a larger group of altered tephras that are useful for stratigraphic correlation and for interpreting the geodynamic evolution of our planet bentonites generally form by diagenetic or hydrothermal alteration under the influence of fluids with high mg content and that leach alkali elements smectite composition is partly controlled by parent rock chemistry studies have shown that k bentonites often display variations in layer charge and mixed layer clay ratios and that these correlate with physical properties and diagenetic history the following is a review of known k bentonite and related occurrences of altered tephra throughout the timescale from precambrian to cenozoic

a new glacier inventory for the jostedalsbreen region norway from landsat tm scenes of 2006 and changes since 1966 pronounced changes in glacier mass and length were observed for the monitored glaciers in the jostedalsbreen region norway since the last glacier inventories were compiled in the 1960s and 1980s however the current overall extent of the glaciers in the region is not well known to obtain this information we have compiled a new inventory from two mosaicked landsat thematic mapper tm scenes acquired in 2006 that have excellent snow conditions for glacier mapping the first suitable scenes for this purpose after 22 years of imaging with tm drainage divides and topographic inventory parameters were derived from a 25 m national digital elevation model for 1450 glaciers by digitizing glacier outlines from 1 50 000 scale topographic maps of 1966 we calculated changes in glacier area for 300 glaciers cumulative length changes for the 1997 2006 period were derived from an additional tm scene and compared with field measurements for nine glaciers overall we find a 9 area loss since 1966 with a clear dependence on glacier size however seasonal snow in 1966 in some regions made area determination challenging the satellite derived length changes confirmed the observed high spatial variability and were in good agreement with field data 1 pixel apart from glacier tongues in cast shadow the new inventory will be freely available from the global land ice measurements from space glims glacier database

the asian monsoon over the past 640 000 years and ice age terminations oxygen isotope records from chinese caves characterize changes in both the asian monsoon and global climate here using our new speleothem data we extend the chinese record to cover the full uranium thorium dating range that is the past 640 000 years the record s length and temporal precision allow us to test the idea that insolation changes caused by the earth s precession drove the terminations of each of the last seven ice ages as well as the millennia long intervals of reduced monsoon rainfall associated with each of the terminations on the basis of our record s timing the terminations are separated by four or five precession cycles supporting the idea that the 100 000 year ice age cycle is an average of discrete numbers of precession cycles furthermore the suborbital component of monsoon rainfall variability exhibits power in both the precession and obliquity bands and is nearly in anti phase with summer boreal insolation these observations indicate that insolation in part sets the pace of the occurrence of millennial scale events including those associated with terminations and unfinished terminations records of the asian monsoon have been extended to 640 000 years ago and confirm both that the 100 000 year ice age cycle results from integral numbers of precessional cycles and that insolation influences the pacing of major millennial scale climate events prior records of the asian monsoon have revealed cyclic variations over hundreds of thousands of years probably driven by variations in insolation caused by the precession of earth s orbit hai cheng and colleagues now provide a speleothem record from chinese cave samples that extends earlier records to 640 000 years ago close to the maximum age possible with uranium thorium dating this spectacular record confirms that the characteristic 100 000 year ice age cycle corresponds to an integral number four or five of precession cycles and that insolation influences millennial scale variations in monsoon strength

evaluation of aster gdem and srtm and their suitability in hydraulic modelling of a glacial lake outburst flood in southeast tibet the resolution and accuracy of digital elevation models dems can affect the hydraulic simulation results for predicting the effects of glacial lake outburst floods glofs however for the tibetan plateau high quality dem data are often not available leaving researchers with near global freely available dems such as the advanced spaceborne thermal emission and reflection radiometer global digital elevation model aster gdem and the shuttle radar topography mission data srtm for hydraulic modelling this study explores the suitability of these two freely available dems for hydraulic modelling of glofs our study focused on the flood plain of a potentially dangerous glacial lake in southeastern tibet to evaluate the elevation accuracy of aster gdem and srtm and their suitability for hydraulic modelling of glofs the elevation accuracies of aster gdem and srtm were first validated against field global position system gps survey points and then evaluated with reference to the relatively high precision of 1 50 000 scale dem dem5 constructed from aerial photography moreover the dem5 aster gdem and srtm were used as basic topographic data to simulate peak discharge propagation as well as flood inundation extent and depth in the hydrologic engineering center s river analysis system one dimensional hydraulic model results of the three dem predictions were compared to evaluate the suitability of aster gdem and srtm for glof hydraulic modelling comparisons of aster gdem and srtm each with dem5 in the flood plain area show root mean square errors between the former two as 15 4 m and between the latter two as 13 5 m although srtm overestimates and aster gdem underestimates valley floor elevations both dems can be used to extract the elevations of required geometric data i e stream centre lines bank lines and cross sections for flood modelling however small errors still exist in the cross sections that may influence the propagation of peak discharge the flood inundation extent and mean water depths derived from aster gdem predictions are only 2 2 larger and 2 3 m deeper than that of the dem5 predictions whereas the srtm yields a flood zone extent 6 8 larger than the dem5 prediction and a mean water depth 2 4 m shallower than the dem5 prediction the modelling shows that in the absence of high precision dem data aster gdem or srtm dem can be relied on for simulating extreme glofs in southeast tibet copyright 2011 john wiley sons ltd

weathering and alteration of volcanic ashes in various depositional settings during the permian triassic transition in south china mineralogical elemental and isotopic approaches to better understand the alteration of volcanic ash in different depositional environments we measured the clay mineralogy major and trace element geochemistry and sr and nd isotopic composition of altered ashes in two permian triassic boundary ptb successions in southern china the pengda and xinmin sections in guizhou province represent different depositional settings allowing us to investigate the role of the early burial environment on authigenic clay formation the ptb ash beds in both sections consist predominantly of mixed layer illite smectite clays altered ashes in the relatively shallow pengda section contain predominantly r2 and r3 i s clays with 70 to 85 illite layers whereas their stratigraphic equivalents in the deeper xinmin section contain only r3 i s clays which are of two types with 88 and 99 illite layers respectively the two studied ash beds can be stratigraphically correlated between the pengda and xinmin sections and show similar 143nd 144nd ratios 0 511991 for pd 1 and 0 511983 for xm 1 0 512073 for pd 2 and 0 512074 for xm 2 ree distributions and immobile element cross plots are consistent in suggesting that the altered ashes may have originated via felsic volcanism altered ashes in the deep sea xinmin section have notably high 87sr 86sr ratios 0 764209 and 0 795921 relative to those from equivalent horizons in shallower environments 0 728455 and 0 749953 this difference in 87sr 86sr ratios is likely attributable to different degrees of chemical weathering elemental ratios such as sio2 al2o3 k2o al2o3 y sr and zr sr all support more intensive chemical leaching in deep water environments the altered ashes at xinmin contain substantially more k2o than those at pengda suggesting greater incorporation of k into clay minerals due to lower ph during early diagenesis clay mineral assemblages and stacking structures of i s clays in the altered ashes are consistent with a general sequence of smectite illitization during diagenesis and burial metamorphism in both sections

landsat based inventory of glaciers in western canada 1985 2005 abstract we report on a glacier inventory for the canadian cordillera south of 60 n across the two western provinces of british columbia and alberta containing 30 000 km2 of glacierized terrain our semi automated method extracted glacier extents from landsat thematic mapper tm scenes for 2005 and 2000 using a band ratio tm3 tm5 we compared these extents with glacier cover for the mid 1980s from high altitude aerial photography for british columbia and from landsat tm imagery for alberta a 25 m digital elevation model dem helped to identify debris covered ice and to split the glaciers into their respective drainage basins the estimated mapping errors are 3 4 and arise primarily from seasonal snow cover glaciers in british columbia and alberta respectively lost 10 8 3 8 and 25 4 4 1 of their area over the period 1985 2005 the region wide annual shrinkage rate of 0 55 a 1 is comparable to rates reported for other mountain ranges in the late twentieth century least glacierized mountain ranges with smaller glaciers lost the largest fraction of ice cover the highest relative ice loss in british columbia 24 0 4 6 occurred in the northern interior ranges while glaciers in the northern coast mountains declined least 7 7 3 4

changes in glacial lakes and glaciers of post 1986 in the poiqu river basin nyalam xizang tibet glacial lakes and glaciers are sensitive indicators of recent climate change in the poiqu river basin of southern tibet 60 100 km nw of mt everest landsat imagery defines post 1986 changes in the size and distribution of both glacial lakes and glaciers total area of glaciers in the 229 km2 drainage area has decreased by 20 the number of glacial lakes with areas in excess of 0 020 km2 has increased by 11 and the total area of glacial lakes has increased by 47 the areas of typical large glacial lakes of the area galongco gangxico and cirenmaco have increased by 104 118 and 156 respectively and these increases are confirmed by field investigations comparing the 1986 data the area of glaciers in the basin headwaters has decreased by 46 18 km2 to a present total area of 183 12 km2 an annual rate of change of 3 30 km2 year trends indicate that the total area of glaciers will continue to decrease and that both the numbers and areas of glacial lakes will continue to increase accompanying these trends will be an increased risk of debris flows formed by entrainment of sediment in glacial outburst floods and in surges from both failure and avalanche and landslide induced overtopping of moraine dams based on both the local and world wide history of catastrophes from flows of these origins disaster mitigation must be planned and appropriate engineering countermeasures put in place as soon as possible

east asian monsoon variability since the mid holocene recorded in a high resolution absolute dated aragonite speleothem from eastern china abstract paleoclimatic conditions associated with the east asian monsoon are reconstructed for the mid to late holocene using 18o values 819 measurements from a precisely dated 10 230th dates aragonite stalagmite from lianhua cave hunan province china 18o values 1 6 to 7 0 are interpreted to reflect the precipitation amount effect related to the strength of summer monsoonal circulation throughout this period the intensity of east asian summer monsoonal circulation declined in response to changes in insolation and a southward shift in the intertropical convergence zone itcz punctuating this first order trend are abrupt millennial to decadal scale fluctuations the most prominent of which occurred around 3337 5 yr bp and records a dramatic weakening in summer monsoonal circulation that coincides with the beginning of neoglacial conditions comparisons between the 18o values of stalagmite a1 and previously published data from stalagmite hs 4 from heshang cave and stalagmites d4 and da from dongge cave china demonstrate a similar regional response to changes in east asian monsoonal circulation several spectral analysis techniques and wavelet analysis were applied to these stalagmite records to evaluate the nature and character of cyclicity in the east asian monsoon during the holocene multi taper method mtm lomb scargle and single spectrum analysis ssa results reveal common periodicities that are unlikely to be artifacts of any single technique the periodicities expressed in the stalagmite 18o records occur at both solar and non solar frequencies and support previous interpretations that variability in monsoonal circulation responds to both solar forcing and internal climatic mechanisms wavelet analysis demonstrates that some of these frequencies are intermittent and recur at semi regular intervals which may indicate long term cyclicity that is unconstrained by the chronology of the record

a reconciled estimate of glacier contributions to sea level rise 2003 to 2009 glaciers distinct from the greenland and antarctic ice sheets are losing large amounts of water to the world s oceans however estimates of their contribution to sea level rise disagree we provide a consensus estimate by standardizing existing and creating new mass budget estimates from satellite gravimetry and altimetry and from local glaciological records in many regions local measurements are more negative than satellite based estimates all regions lost mass during 2003 2009 with the largest losses from arctic canada alaska coastal greenland the southern andes and high mountain asia but there was little loss from glaciers in antarctica over this period the global mass budget was 259 28 gigatons per year equivalent to the combined loss from both ice sheets and accounting for 29 13 of the observed sea level rise

pacific east asian teleconnection how does enso affect east asian climate observational evidence is presented to show a teleconnection between the central pacific and east asia during the extreme phases of enso cycles this pacific east asian teleconnection is confined to the lower troposphere the key system that bridges the warm cold events in the eastern pacific and the weak strong east asian winter monsoons is an anomalous lower tropospheric anticyclone cyclone located in the western north pacific the western north pacific wind anomalies develop rapidly in late fall of the year when a strong warm or cold event matures the anomalies persist until the following spring or early summer causing anomalously wet dry conditions along the east asian polar front stretching from southern china northeastward to the east of japan kuroshio extension using atmospheric general circulation and intermediate models the authors show that the anomalous philippine sea anticyclone results from a rossby wave response to suppressed convective heating which is induced by both the in situ ocean surface cooling and the subsidence forced remotely by the central pacific warming the development of the anticyclone is nearly concurrent with the enhancement of the local sea surface cooling both the anticyclone and the cooling region propagate slowly eastward the development and persistence of the teleconnection is primarily attributed to a positive thermodynamic feedback between the anticyclone and the sea surface cooling in the presence of mean northeasterly trades the rapid establishment of the philippine sea wind and sst anomalies implies the occurrence of extratropical tropical interactions through cold surge induced exchanges of surface buoyancy flux the central pacific warming plays an essential role in the development of the western pacific cooling and the wind anomalies by setting up a favorable environment for the anticyclone sst interaction and midlatitude tropical interaction in the western north pacific

a detailed comparison of asian monsoon intensity and greenland temperature during the allerod and younger dryas events abstract an annual layer counted and 230th dated stalagmite oxygen isotope record from qingtian cave in hubei province central china provides an asian monsoon am history across the allerod to younger dryas yd transition with an average 2 5 year resolution seasonal 18o profiles indicate that the calcite 18o is a sensitive proxy for am changes and the close similarity between the qingtian and other cave records from eastern china suggests a large scale regional coherence of monsoonal precipitation 18o variations associated with the temperature changes in high northern latitudes the annually resolved chronology with a u th age uncertainty of less than 100 yr defines the timing duration and transition of the early allerod the intra allerod cold period iacp the late allerod and the start of the yd the 160 yr long iacp with two brief reversals is clearly shown in both 18o and lamina thickness records the early and late allerod separated by the iacp are characterized by several decadal to centennial cycles of 18o variations each punctuated by sub cycles these decadal to centennial monsoon variations correlate with the greenland temperature changes supporting a model simulation that the decadal north atlantic oscillation nao and north pacific oscillation npo are coupled via atmospheric circulation under glacial boundary conditions perhaps affecting tropical subtropical monsoon changes however the monsoon transition between the late allerod and yd lasted 380 yr longer than the analogous greenland temperature shift by at least 130 yr stuiver m grootes p m gisp2 oxygen isotope ratios quat res 53 2000 277 284 this implicates other links besides the direct link between greenland and the am which is now well documented one possibility is the influence by southern hemisphere climate via cross equatorial air flow an z s the history and variability of the east asian paleomonsoon climate quat sci rev 19 2000 171 187

changes in glacier extent and surface elevations in the depuchangdake region of northwestern tibet china abstract remote sensing data including those from landsat thematic mapper enhanced thematic mapper plus tm etm the shuttle radar topography mission digital elevation model srtm4 1 dem and the geoscience laser altimeter system ice cloud and land elevation satellite glas icesat show that from 1991 to 2013 the glacier area in the depuchangdake region of northwestern tibet decreased from 409 to 393 km 2 an overall loss of 16 km 2 or 3 9 of the entire 1991 glacial area the mean glacier thinning rate was 0 40 0 16 m equivalent height of water per year w e yr equating to a glacier mass balance of 0 16 0 07 km 3 w e yr total mass loss from 2003 to 2009 was 1 13 0 46 km 3 glacier retreat likely reflects increases in annual total radiation annual positive degree days and maximum temperature with concurrent increases in precipitation insufficient to replenish glacial mass loss the rate of glacier retreat in depuchangdake is less than that for himalayan glaciers in indian monsoon dominated areas but greater than that for karakoram glaciers in mid latitude westerly dominated areas glacier type climate zone and climate change all impact on the differing degrees of long term regional glacial change rate however special glacier distribution forms can sometimes lead to exceptional circumstances

enso variability reflected in precipitation oxygen isotopes across the asian summer monsoon region abstract oxygen isotope signals 18 o from paleo archives are important proxies for past asian summer monsoon asm climate reconstruction however causes of interannual variation in the 18 o values of modern precipitation across the asm region remain in argument we report interannual 18 o variation in southern tibetan plateau precipitation based on long term observations at lhasa these data together with precipitation 18 o records from five global network of isotopes in precipitation gnip stations and two ice core 18 o records were used to define a regional metric of asm precipitation 18 o asmoi back trajectory analyses for rainy season precipitation events indicate that moisture sources vary little between years with relatively high and low 18 o values a result that is consistent for the south lhasa southeast bangkok and east asm regions hong kong in contrast 18 o values at these three locations are significantly correlated with convection in the estimated source regions and along transport paths these results suggest that upstream convection rather than moisture source change causes interannual variation in asm precipitation 18 o values contrasting values of the asmoi in el nino and la nina years reveal a positive isotope el nino southern oscillation enso response e g high values corresponding to warm phases which we interpret as a response to changes in regional convection we show that the isotope enso response is amplified at high elevation sites and during la nina years these findings should improve interpretations of paleo 18 o data as a proxy for past asm variation and provide new opportunities to use data from this region to study paleo enso activity

variations of glacial lakes and glaciers in the boshula mountain range southeast tibet from the 1970s to 2009 catastrophic floods originating from glacial lake outbursts have recently become one of the primary natural hazards in the southeastern tibetan plateau here we report observations of glacial lake expansions and glacier recessions in the boshula mountain range southeast tibet derived from multitemporal remote sensing images and digital elevation models during the period from the 1970s to 2009 the area of glacial lakes has expanded from 9 24 0 1 km 2 in the 1970s to 10 96 0 1 km 2 in 2009 specifically the area of moraine dammed lakes has increased by 26 8 from the 1970s to 2009 the glacierized area in the boshula mountain range shrank by 12 7 21 2 km 2 increasing mean summer air temperature was the main cause for the glacier recession and lake expansion from the 1970s to 2001 while the combination of increased summer temperature and decreased summer precipitation led to accelerated glacier recession after 2001 climate warming and ongoing deglaciation play important roles in the expansion of moraine dammed lakes calling for intensified monitoring to properly address the hazard potential in the study area

the glacier inventory of china following recommendations from the international commission on snow and ice for a world glacier inventory an inventory of glaciers in china was carried out by chinese glaciologists from 1978 to 2002 each glacier was measured from aerial photographs and topographical maps and 34 parameters recorded these parameters were then analyzed statistically for the various river systems in china twelve volumes of the glacier inventory of china gic have been published consisting of 22 parts in 21 books the data were subsequently abridged into a concise gic published in chinese 2005 and in english 2008 to make the glacier inventory more accessible and better adapted for assessing glacier response to climate change after the gic was completed new aerial photographs became available and remote sensing techniques became more common to investigate glacier changes since completion of the first gic a second glacier inventory of china was initiated in 2007 this 5 year project supported by the ministry of science and technology will be undertaken mainly using remote sensing techniques

analysis and characterization of the vertical accuracy of digital elevation models from the shuttle radar topography mission 1 the first near global high resolution digital elevation model dem of the earth has recently been released following the successful shuttle radar topography mission srtm of 2000 this data set will have applications in a wide range of fields and will be especially valuable in the earth sciences prior to widespread dissemination and use it is important to acquire knowledge regarding the accuracy characteristics in this work a comprehensive analysis of the vertical errors present in the data set and the assessment of their effects on different hydrogeomorphic products is performed in particular the work consisted of 1 measuring the vertical accuracy of the data set in two areas with different topographic characteristics 2 characterizing the error structure by comparing elevation residuals with terrain attributes 3 assessing a wavelet based filter for removing speckle and 4 assessing the effects of vertical errors on hydrogeomorphic products and on slope stability modeling the results indicate that in the two sites relief has a strong effect on the vertical accuracy of the srtm dem in the high relief terrain large errors and data voids are frequent and their location is strongly influenced by topography while in the low to medium relief site errors are smaller although the hilly terrain still produces an effect on the sign of the errors speckling generates deviations in the drainage network in one of the investigated areas but the application of a wavelet filter proved to be an effective tool for removing vertical noise although further fine tuning is necessary vertical errors cause differences in automatically extracted hydrogeomorphic products that range between 4 and 1090

contrasting the indian and east asian monsoons implications on geologic timescales the surface winds over the arabian sea and south china sea are meaningful indicators for the strength of the indian monsoon and east asian monsoon respectively paleo monsoon variability has been studied through analysis of sediment records from these two monsoon regions to facilitate interpretation of these records we focus on the impacts of internal and external forcing of the monsoon system by contrasting the annual cycle and interannual variability of two subsystems the monsoon over the indian sector 40 105 e and over the east asian sector 105 160 e differences in the annual cycle within these subsystems arise primarily from the different land ocean configurations that determines atmospheric response to the solar forcing thus factors that drive intensities of the monsoonal annual cycle share common features with the external geographic and orbital forcing that controls paleomonsoon variability we show that the differences in interannual variations between the two monsoon subsystems are primarily due to internal factors of the coupled atmosphere ocean land system such as remote impacts of el nin o la nin a and local monsoon ocean interactions the mechanisms that operate on interannual to interdecadal timescales may differ fundamentally from that on geologic orbital timescales the low level flows over the east asia and australia are essentially established by geographic forcing the amplification of the australia summer monsoon during increased solar precession is likely caused by an enhanced east asian winter monsoon rather than following an enhanced indian summer monsoon as on the interannual timescale it is also found that el nin o influences the low level flow moderately over the arabian sea but to a greater extent over the south china sea as such large changes in the pacific thermal conditions may significantly alter the intensity of the east asian monsoon but not the indian monsoon

holocene east asian summer monsoon records in northern china and their inconsistency with chinese stalagmite δ18o records abstract monsoon precipitation over china exhibits large spatial differences it has been found that a significantly enhanced east asian summer monsoon easm is characterized by increased rainfall in northern china and by reduced rainfall in southern china and this relationship occurs on different time scales during the holocene this study presents results from a diverse range of proxy paleoclimatic records from northern china where precipitation variability is traditionally considered as an easm proxy our aim is to evaluate the evolution of the easm during the holocene and to compare it with all of the published stalagmite 18 o records from the asian monsoon region in order to explore the potential mechanism s controlling the chinese stalagmite 18 o we found that the intensity of the easm during the holocene recorded by the traditional easm proxy of moisture or precipitation records from northern china is significantly different from the chinese stalagmite 18 o records the easm maximum occurred during the mid holocene challenging the prevailing view of an early holocene easm maximum mainly inferred from stalagmite 18 o records in eastern china in addition all of the well dated holocene stalagmite 18 o records covering a broad geographical region exhibit a remarkably similar trend of variation and are statistically well correlated on different time scales thus indicating a common signal however in contrast with the clear consistency in the 18 o values in all of the cave records both instrumental and paleoclimatic records exhibit significant spatial variations in rainfall on decadal to centennial time scales over eastern china in addition both paleoclimatic records and modeling results suggest that holocene east asian summer monsoon precipitation reached a maximum at different periods in different regions of china thus the stalagmite 18 o records from the easm region should not be regarded as a reliable indicator of the strength of the east asian summer monsoon furthermore modern observations indicate that the moisture for precipitation in the east asian monsoon region is mainly derived from the indian ocean the moisture transport route from the indian ocean to the east asian monsoon region during the holocene is almost identical to that of modern precipitation therefore the strong correlation of 18 o records in the easm and indian summer monsoon ism regions and the similarity of the pattern of latitudinal changes in 18 o values in stalagmites and in modern meteoric precipitation along the water vapor transport route further suggests that the stalagmite 18 o records from the easm region are essentially a signal of the isotopic composition of precipitation which is determined mainly by changes in the 18 o of atmospheric vapor in the upstream source region over the indian ocean and indian monsoon region via the upstream depletion mechanism finally the main trends of the stalagmite 18 o records are strongly correlated with the known evolution of the ism and therefore these records reflect the history of the ism rather than that of the easm our findings support the conclusion that easm variability is mainly controlled by northern hemisphere summer insolation and was strongly modulated by ice volume during the last deglaciation and early holocene which delayed the response of the easm maximum to peak insolation forcing

glacial evolution in the ayilariju region western himalaya china 1980 2011 changes in glacial geometries extent and surface elevations in the ayilariju region of western himalaya china were investigated using topographical maps and data from the landsat thematic mapper enhanced thematic mapper plus the satellite pour l observation de la terre spot4 the shuttle radar topography mission 4 1 digital elevation model and geographical information system techniques the results showed that the total glaciated area decreased from 190 37 to 162 52 km2 14 6 of the 1980 glaciated area from 1980 to 2011 furthermore total glacial mass loss of studied region was estimated to be 2 570 0 327 km3 between 1980 and 2000 further investigation on meteorological data indicated that increases of temperature and total radiation were the primary causes of accelerated glacial melting reduced wind speed and slight decreases in precipitation triggered by weakening of the south asian summer monsoon due to warming may also have contributed to glacial shrinkage the rate of glacial retreat in the studied region is lower than that in the southern himalayan region but larger than that in the karakoram primarily because ayilariju glaciers were located on the margin of the indian monsoon dominated region

holocene moisture evolution in arid central asia and its out of phase relationship with asian monsoon history we synthesize palaeoclimate records from the mid latitude arid asian region dominated today by the westerlies arid central asia aca to evaluate spatial and temporal patterns of moisture changes during the holocene sediment records from i i takes with reliable chronologies and robust proxies were selected to reconstruct moisture histories based on a five class ordinal wetness index with assigned scores from the driest to wettest periods at individual sites for 200 year time slices the proxies used in these records include pollen and diatom assemblages sediment lithology lake levels and geochemistry mainly isotope data the results of our synthesis show that aca as a whole experienced synchronous and coherent moisture changes during the holocene namely a dry early holocene a wetter less dry early to mid holocene and a moderately wet late holocene during the early holocene most of the lakes experienced very low water levels and even dried out before ca 8 ka 1 ka 1000cal a bp hence the effective moisture history in aca is out of phase with that in monsoonal asia as documented by numerous palaeoclimate records in monsoonal asia a strong summer monsoon and humid climate characterized the early holocene and a weakened summer monsoon and drier climate prevailed during the late holocene which were mainly controlled by changes in low latitude summer insolation in contrast we propose that the pattern of holocene effective moisture evolution in the westerly dominated aca was mainly determined by north atlantic sea surface temperatures ssts and high latitude air temperatures that affect the availability amount and transport of water vapor also topography of the tibetan plateau and adjacent asian highlands could have contributed to the intensification of dry climate in aca during the early holocene as a result of strengthening the subsidence of dry air masses associated with stronger uplift motion on the plateau by intense heating under a stronger summer insolation summer insolation might have played a key role in directly controlling moisture conditions in aca but only after the northern hemisphere ice sheets had disappeared in the mid and late holocene c 2007 elsevier ltd all rights reserved

comparison of satellite derived with ground based measurements of the fluctuations of the margins of vatnajokull iceland 1973 92 vatnajokull iceland is the earth s most studied ice cap and represents a classical glaciological field site on the basis of s palsson s seminal glaciological field research in the late 18th century since the 19th century vatnajokull has been the focus of an array of glaciological studies by scientists from many nations including many remote sensing investigations since 1951 landsat derived positions of the termini of 11 outlet glaciers of vatnajokull were compared with frontal positions of six of these 11 outlet glaciers determined by field observations during the period 1973 92 the largest changes during the 19 year period 1973 92 occurred in the large lobate surge type outlet glaciers along the southwestern western and northern margins of vatnajokull tungnaarjokull receded 1413 112 m 1380 1 m from ground observations and bruarjokull receded 1975 191 m 2096 5 m from extrapolated ground observations between 1973 and 1992 satellite images can be used to delineate glacier margin changes on a time lapse basis if the glacier margin can be spectrally discriminated from terminal moraines and sandur deposits and if the advance recession is larger than maximum image pixel size local knowledge of glaciers is critically important however in the accurate delineation of glacier margins on landsat images

illite smectite structural changes during metamorphism in black cambrian alum shales from the baltic area illite smectite i s from cambrian black shale of both early diagenetic and anchimetamorphic grade was investigated to determine the mechanism of the clay transformation the layer sequences the distribution of thicknesses of coherent scattering domains csds and the three dimensional ordering were determined by x ray diffraction xrd the proportions of cis vacant cv and transvacant tv 2 1 layers were determined by thermal analysis and the proportion and distribution of interlayer ammonium by xrd and by infared spectroscopy ir the structural formulae were determined from total chemical analysis and mossbauer and 27al nmr spectroscopies and the particle shape and size investigated by atomic force microscopy afm in the early diagenetic samples the i s is composed of two phases one of which contains 0 05 and the other 0 25 smectite s interlayers the first phase does not change during metamorphism in the second phase 0 20 s are converted to tobelite t layers through fixation of formula 1 but the i layers are not changed simultaneously the proportion of cv layers changes from 0 18 to 0 02 and the tetrahedral substitution of al for si is parallel to the increase in t layers all i interlayers contain 0 75k per o10 oh 2 further more the metamorphism results in increasing mean thickness of csds from 5 1 6 8 nm for the low diagenetic samples to 6 7 8 4 nm for the anchimetamorphic samples we conclude that the tobelitization was accompanied by transformation of cv to tv 2 1 layers adjacent to the smectite interlayers and formation of tv layers adjacent to the newformed tobelite interlayers in otherwise intact crystallites this mechanism only partly resembles the tobelitization previously observed in the upper jurassic north sea oil source rocks i s in these rocks contained tv 2 1 layers and t interlayers formed through solid state al for si substitution in the tetrahedral sheet and by ammonium fixation in the corresponding interlayers these different mechanisms are probably because the north sea i s originated from weathered illite like the cambrian high illitic phase whereas the cambrian low illitic phase undergoing the transformation originated from cv smectite of volcanic origin the results indicate that the illitization in oil source rocks is linked to oil generation and that it deviates from the illitization in other rocks because of the supply of ammonium formed during oil generation and the fixation of this ammonium in the former smectite interlayers 1 embed tex math 1 gif

consideration of the errors inherent in mapping historical glacier positions in austria from the ground and space 1893 2001 the historical record of in situ measurements of the terminus positions of the pasterze and kleines fleiskees glaciers in the eastern alps of austria is used to assess uncertainties in the measurement of decadal scale changes using satellite data topographic maps beginning in 1893 and satellite data from 1976 to 2001 were studied in concert with ground measurements to measure glacier changes ground measurements show that the tongue of the pasterze glacier receded f1150 m from 1893 to 2001 while satellite derived measurements using august 2001 landsat enhanced thematic mapper plus etm data registered to an 1893 topographic map show a recession of 1300 1800 m with an unknown error the measurement accuracy depends on the registration technique and the pixel resolution of the sensor when two satellite images are used when using topographic maps an additional source of error is the accuracy of the glacier position shown on the map between 1976 and 2001 landsat derived measurements show a recession of the terminus of the pasterze glacier of 479f136 m at an average rate of 19 1 m a 1 while measurements from the ground showed a recession of 428 m at an average rate of 17 1 ma 1 four meter resolution ikonos satellite images from 2000 and 2001 reveal a shrinkage of 22 096f46 m 2 in the pasterze tongue the nearby kleines fleiskees glacier lost 30 of its area between 1984 and 2001 and the area of exposed ice increased by 0 44f0 0023 km 2 according to landsat satellite measurements as more recent satellite images are utilized especially data that are geocoded the uncertainty associated with measuring glacier changes has decreased it is not possible to assess the uncertainty when an old topographic map and a satellite image are coregistered

interpreting rock eval pyrolysis data using graphs of pyrolizable hydrocarbons vs total organic carbon kerogen the major organic component of sedimentary rocks is commonly analyzed by rock eval pyrolysis plotting the data on a graph of s 2 vs total organic carbon toc and determining the regression equation is the best method for determining the true average hydrogen index and measuring the adsorption of hydrocarbon by the rock matrix such a plot also indicates the type of kerogen present and avoids the problem of increasing hydrogen index with total organic carbon content with the s 2 vs toc diagram the organic component of different suites of samples may be compared and their petroleum generation potentials established as an example the diagrams are used to evaluate the sedimentary environments and petroleum potential of the paleogene evaporitic sediments of the mulhouse basin alsace france

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

holocene variability of the east asian summer monsoon from chinese cave records a re assessment oxygen isotope records from stalagmites in caves in southern china interpreted as proxy rainfall records reflecting the intensity of the east asian summer monsoon indicate gradual monsoon weakening for the last 9000 years as also documented for the indian monsoon coupled with high precision dating the speleothem proxy records have been used to test monsoon links with orbital forcing solar changes iceberg discharges in the north atlantic ocean currents and atmospheric methane however these benchmark cave records do not match other published dated e asian proxy rainfall record specifically here independently calibrated rainfall records from loess palaeosol magnetic properties and cave oxygen isotope intercomparisons which show variable e asian monsoon intensity through the entire holocene the strong correlation of the cave records with the extraregional indian monsoon record yet their mismatch with these other dated chinese rainfall records might be reconciled if the speleothem isotope variations reflect not changes in holocene rainfall amount but in rainfall source declining holocene influence of isotopically lighter indian monsoon sourced moisture over china would have resulted in increasing proportions of isotopically heavier rainfall sourced from the more oceanic e asian monsoon individual speleothems may thus regionally record holocene changes in indian monsoon intensity and isotopic influence conversely the other chinese proxy records described here reflect changes in rainfall amount and thus in e asian summer monsoon intensity for the holocene the e asian and the indian monsoon responses to orbital forcing are likely to have differed specifically due to e asian internal feedbacks and the seasonal contrasts between the two monsoon systems

ice wastage on the kerguelen islands 49 s 69 e between 1963 and 2006 1 we observed the wastage of ice masses on the kerguelen islands indian ocean 49 s 69 e using historical information and recent satellite data overall the total ice covered area on the islands declined from 703 to 552 km2 between 1963 and 2001 a reduction of 21 the area of cook ice cap the main ice body decreased asymmetrically from 501 to 403 km2 west flowing glaciers lost 11 of their area while east flowing glaciers lost 28 after 1991 the retreat rate accelerated from 1 9 km2 a 1963 1991 to 3 8 km2 a 1991 2003 between 1963 and 2000 the ice volume loss was 25 30 km3 equivalent to an area average ice thinning rate of 1 4 1 7 m a the glacial retreat took place in the climatic context of a relatively low level of precipitation compared to the 1950s and a 1 c warming that occurred between 1964 and 1982 the acceleration of the ice losses since at least the 1990s indicates that the state of the ice bodies on the kerguelen islands is still far from balanced together with other studies in patagonia south georgia and heard island our analysis is consistent with a pattern of strong and accelerated wastage of ice masses influenced by the southern ocean

the origin of tonsteins an overview and links with seatearths fireclays and fragmental clay rocks abstract tonsteins are volcanic ash falls in coal bearing sequences that have altered to kaolinite only in the last twenty years or so has the volcanic origin become firmly established the evidence for the volcanic origin encompasses bed form including lateral extent structures textures volcanogenic mineralogy and geochemistry the lines of evidence are reviewed from a historical perspective tonsteins came to prominence over a hundred years ago because of their stratigraphic value tonsteins continue to be of value in coalfield exploration but their stratigraphic value has been enhanced in recent years with the ability to determine radiometric ages with a high level of accuracy the geochemistry not only provides good evidence for the volcanic origin but also enables tectomagmatic deductions to be made for areas external to the coal basin in addition some tonsteins are the indicators for the discovering of rare metal ore deposits nb rees and ga there is also the potential to use the geochemistry to identify specific tonsteins essentially a chemostratigraphic approach tonsteins are seen as one class of bentonites others include k bentonites metatonsteins and possibly illitic bentonites tonsteins have been linked to seatearths fireclays and fragmental clay rocks although all such rocks contain kaolinite the origins differ the seatearths contain rootlets and were subjected to pedogenic activity alteration of the silicate minerals is limited under conditions of a high water table and in the presence of organic matter reducing conditions prevailed leading to gleization on the other hand the fireclays show extensive alteration to kaolinite there is a link with the major marine bands and this has implications in terms of sequence stratigraphy the fragmental clayrocks have also been linked to soil forming processes but in this case possibly the reworked soil was the product of an open system containing free alumina minerals that reacted with silica in solution during diagenesis

how to measure the strength of the east asian summer monsoon defining the intensity of the east asian summer monsoon easm has been extremely controversial this paper elaborates on the meanings of 25 existing easm indices in terms of two observed major modes of interannual variation in the precipitation and circulation anomalies for the 1979 2006 period the existing indices can be classified into five categories the east west thermal contrast north south thermal contrast shear vorticity of zonal winds southwesterly monsoon and south china sea monsoon the last four types of indices reflect various aspects of the leading mode of interannual variability of the easm rainfall and circulations which correspond to the decaying el nino while the first category reflects the second mode that corresponds to the developing el nino the authors recommend that the easm strength can be represented by the principal component of the leading mode of the interannual variability which provides a unified index for the majority of the existing indices this new index is extremely robust captures a large portion 50 of the total variance of the precipitation and three dimensional circulation and has unique advantages over all the existing indices the authors also recommend a simple index the reversed wang and fan index which is nearly identical to the leading principal component of the easm and greatly facilitates real time monitoring the proposed index highlights the significance of the mei yu baiu changma rainfall in gauging the strength of the easm the mei yu which is produced in the primary rain bearing system the east asian ea subtropical front better represents the variability of the easm circulation system this new index reverses the traditional chinese meaning of a strong easm which corresponds to a deficient mei yu that is associated with an abnormal northward extension of southerly over northern china the new definition is consistent with the meaning used in other monsoon regions worldwide where abundant rainfall within the major local rain bearing monsoon system is considered to be a strong monsoon

a high resolved record of the asian summer monsoon from dongge cave china for the past 1200 years abstract two annually laminated and 230th dated stalagmite oxygen isotope 18o records from dongge cave china provided a high resolution asian summer monsoon asm history for the past 1200 years a close similarity between annual band thickness and stable isotope analyses 13c and 18o suggests the calcite 18o is most likely a proxy associated with asm precipitation the two duplicated stalagmite 18o records show that the asm varies at a periodicity of 220 years concordant with a dominant cycle of solar activity a period of strong asm activity occurred during the sporer minimum 1450 1550 a d followed by a striking drop circa 1580 a d potentially consistent with the social unrest in the final decades of china s ming dynasty 1368 1644 a d centennial scale changes in asm precipitation over the last millennium match well with changes in tropical atlantic sea surface temperatures ssts and south american summer monsoon precipitation our findings suggest that variations in low latitude monsoon precipitation are probably driven by shifts in the mean position of the intertropical convergence zone itcz which is further mediated by solar activity and tropical ssts

reconstruction of little ice age glacier area and equilibrium line attitudes in the central and western himalaya abstract glacial changes during the little ice age lia in the himalayan mountains are important for understanding changes in the monsoonal and westerly climate of the so called the third pole however knowledge of these changes and their dynamics remains limited because of the region s geographical inaccessibility in addition to geopolitical reasons in this study we used high resolution three dimensional images from google earth to identify lateral and terminal moraines as delineators of paleoglacier boundaries and mapped the boundaries of both modern and lia glaciers arcgis 9 3 software was applied to map data and to calculate glacier lengths and areas modern glacier surface elevation data were derived from srtm shuttle radar topography mission records three methods the toe to headwall altitude ratio thar the toe to summit altitude method tsam and the toe to ridge altitude method tram were used to estimate equilibrium line altitude ela the transient snowlines tsl of ninety one modern glaciers were acquired using landsat 8 oli images in late summer to evaluate the reliability of the calculated elas our results showed that the total length and total area of two hundred and twenty glaciers in the central and western himalaya cwh had decreased respectively by 35 and 31 since the lia the tram method was the preferred method for the reconstruction of elas the mean depression of elas from the lia to the first decade of the 21st century as reconstructed using the tram method was 123 m the ela depression and rate of change of glacier length and glacier area displayed generally increasing trends from west to east along the central and western himalaya suggesting that the moisture was most likely transported from an easterly direction these changes were more intensive on southern than northern slopes suggesting that southerly and westerly precipitation likely increased over the same period we speculated that the cwh had been influenced by both the indian summer monsoon ism and westerlies since the lia ism moisture as in modern times was the main factor controlling the distribution of glaciers during the lia further precipitation carried by the westerlies likely intensified along southerly pathways along the cwh during the lia

integrated monitoring of mountain glaciers as key indicators of global climate change the european alps the internationally recommended multi level strategy for monitoring mountain glaciers is illustrated using the example of the european alps where especially dense information has been available through historical times this strategy combines in situ measurements mass balance length change with remote sensing inventories and numerical modelling it helps to bridge the gap between detailed local process oriented studies and global coverage since the 1980s mass balances have become increasingly negative with values close to 1 m w e a 1 during the first 5 years of the 21st century the hot dry summer of 2003 alone caused a record mean loss of 2 45 m w e roughly 50 above the previous record loss in 1998 more than three times the average between 1980 and 2000 and an order of magnitude more than characteristic long term averages since the end of the little ice age and other extended periods of glacier shrinkage during the past 2000 years it can be estimated that glaciers in the european alps lost about half their total volume roughly 0 5 a 1 between 1850 and around 1975 another 25 or 1 a 1 of the remaining amount between 1975 and 2000 and an additional 10 15 or 2 3 a 1 in the first 5 years of this century

orbital scale timing and mechanisms driving late pleistocene indo asian summer monsoons reinterpreting cave speleothem δ18o 1 southeast china cave 18o often interpreted as a pure east asian summer monsoon proxy lags maximum northern hemisphere summer insolation by 2 9 0 3 kyrs at the precession cycle the arabian sea summer monsoon stack lags by 8 1 kyr consistent with 13 other indian and east asian summer monsoon proxies from marine lake and terrestrial archives this 5 kyr phase difference cannot be attributed to age control inadequacies in the marine chronology it requires reconciliation in the context of proxy interpretation both of these lags are incompatible with a direct response to northern hemisphere summer insolation implicating additional forcing mechanisms analysis of heterodynes in the cave 18o spectrum demonstrates that variance contained in the arabian sea summer monsoon proxies also resides in the cave 18o record this variance is subtracted from the cave 18o record yielding a residual that is highly coherent and in phase with precession minima reflecting the impact of winter temperature change on cave 18o meteorological precipitation under cold conditions thus we argue that the timing of light cave 18o peaks cannot be interpreted as reflecting the timing of strong summer monsoons alone the 2 9 kyr precession band phase lag of cave 18o reflects the combined influence of summer monsoon forcing with a phase lag of 8 kyrs relative to precession minima and winter temperature forcing that is in phase with precession minima this interpretation is consistent with modern seasonality in the amount and isotopic composition of rainfall in southeast china

climatic and environmental controls on speleothem oxygen isotope values variations in speleothem oxygen isotope values d 18 o result from a complicated interplay of environmental controls and processes in the ocean atmosphere soil zone epikarst and cave system as such the controls on speleothem d 18 o values are extremely complex an understanding of the processes that control equilibrium and kinetic fractionation of oxygen isotopes in water and carbonate species is essential for the proper interpretation of speleothem d 18 o as paleoclimate and paleoenvironmental proxies and is best complemented by study of site specific cave processes such as infiltration flow routing drip seasonality and saturation state and cave microclimate among others this review is a process based summary of the multiple controls on d 18 o in the atmosphere soil epikarst and speleothem calcite illustrated with case studies primary controls of d 18 o in the atmosphere include temperature and relative humidity through their role in the multiple isotope effects variability and modifications of water d 18 o values in the soil and epikarst zones are dominated by evaporation mixing and infiltration of source waters the isotopically effective recharge into a cave system consists of those waters that participate in precipitation of caco3 resulting in calcite deposition rates which may be biased to time periods with optimal dripwater saturation state recent modeling experimental and observational data yield insight into the significance of kinetic fractionation between dissolved carbonate phases and solid caco3 and have implications for the hendy test to assist interpretation of speleothem d 18 o time series quantitative and semi quantitative d 18 o climate calibrations are discussed with an emphasis on some of the difficulties inherent in using modern spatial and temporal isotope gradients to interpret speleothems as paleoclimate proxy records finally several case studies of globally significant speleothem paleoclimate records are discussed that show the utility of d 18 o to reconstruct past climate

black shales and carbon isotopes in pelagic sediments from the tethyan lower jurassic detailed sampling and analysis of jurassic pelagic limestones and marls from italy hungary and switzerland have enabled construction of an isotope stratigraphy across the pliensbachian toarcian boundary with resolution to the zonal level the oxygen isotope record is unremarkable the carbon isotopes however show two positive excursions one relatively minor during the pliensbachian margaritatus zone subnodosus subzone the other more major during the toarcian early falciferum zone where a maximum 13c value of 4 52 pdb is attained these intervals are known to be favoured periods of organic rich sedimentation in diverse parts of the globe and the isotopic excursions are interpreted as a response to abnormally high rates of storage of organic carbon in the sedimentary record a comparable phenomenon has been documented from the cenomanian turonian boundary in the cretaceous where it has been referred to the influence of an oceanic anoxic event some italian sections spanning this lower jurassic interval contain organic rich shales in the falciferum zone the isotopic signatures from their included locally manganiferous carbonate betray a considerable diagenetic overprint and they cannot therefore be incorporated in a composite isotopic curve carbon isotopes from the organic carbon itself are extremely negative falling to 33 pdb and in one section examined in detail correlate with the calcium carbonate content of the shales they may reflect a partial change to a non calcified planktonic biota during deposition of this lime poor interval possibly responding to upwelling and increased fertility of near surface waters the onset of upwelling may have been as early as spinatum tenuicostatum zone time that is at the pliensbachian toarcian boundary

timing duration and transitions of the last interglacial asian monsoon thorium 230 ages and oxygen isotope ratios of stalagmites from dongge cave china characterize the asian monsoon and low latitude precipitation over the past 160 000 years numerous abrupt changes in 18o 16o values result from changes in tropical and subtropical precipitation driven by insolation and millennial scale circulation shifts the last interglacial monsoon lasted 9 7 1 1 thousand years beginning with an abrupt less than 200 years drop in 18o 16o values 129 3 0 9 thousand years ago and ending with an abrupt less than 300 years rise in 18o 16o values 119 6 0 6 thousand years ago the start coincides with insolation rise and measures of full interglacial conditions indicating that insolation triggered the final rise to full interglacial conditions

changes in the glacier extent and surface elevation in xiongcaigangri region southern karakoram mountains china the recent evolution of the karakoram glaciers widely acknowledged as peculiar remains poorly understood the xiongcaigangri region is in the south of karakoram and its glacial melt water has a significant impact on the local water supply and ecosystem in this work glacial changes in the xiongcaigangri region were detected based on topographic maps and landsat mss tm etm oli srtm4 1 dem and glas icesat remote sensing data and gis techniques the results show that from 1968 to 2013 the total glacier area decreased from 181 10 km 2 to 178 47 km 2 an overall loss of 2 63 km 2 or 1 45 of the entire 1968 glacial area the inverse relationship between the retreating area and the change rate indicates that small glaciers may be retreating faster the main glacial melting occurred below 6500 m a s l and the reduction of 2 62 km 2 accounts for 99 62 of the total glacial retreat in the area studied the very slight reduction of 0 01 km 2 over 6500 m a s l accounts for only for 0 38 of the total glacial retreat in the area studied the results also show that the glacier areas are decreasing on all slopes and larger area losses have been observed on smaller slopes whereas smaller area losses have been observed on the larger slopes the different aspects of the study all showed glacier retreat taking place between the period from 1968 to 2013 the largest area decrease is in west and the area lost in the other aspect was comparatively small total glacier mass loss in the xiongcaigangri region is estimated to be 10 97 22 39 10 8 m 3 w e between 1968 and 2000 the average elevation loss estimated from the icesat and 2000 srtm difference was from 4 69 3 40 m per year and the average elevation loss between srtm and 1968dem was from 0 92 to 0 66 m per year increasing temperatures along with decreasing precipitation was determined to be the primary factor driving the glacier retreat in the xiongcaigangri region c 2014 elsevier ltd and inqua all rights reserved

chinese stalagmite δ 18 o controlled by changes in the indian monsoon during a simulated heinrich event carbonate cave deposits in india and china are assumed to record the intensity of monsoon precipitation because the 18 o of the carbonate tracks the isotopic signature of precipitation these records show spatially coherent variability throughout the last ice age and suggest that monsoon strength was altered during the millennial scale climate variations known as dansgaard oeschger events and during the heinrich cooling events here we use a numerical climate model with an embedded oxygen isotope model to assess what caused the shifts in the oxygen isotope signature of precipitation during a climate perturbation designed to mimic a heinrich event our simulations show that a sudden increase in north atlantic sea ice extent during the last glacial period leads to cooling in the northern hemisphere reduced precipitation over the indian basin and weakening of the indian monsoon the precipitation is isotopically heavier over india and the water vapour exported to china is isotopically enriched our model broadly reproduces the enrichment of 18 o over northern india and east asia evident in speleothem records during heinrich events we therefore conclude that changes in the 18 o of cave carbonates associated with heinrich events reflect changes in the intensity of indian rather than east asian monsoon precipitation