on the characterization of glacier response by a single time scale glacier response to climate can be characterized by a single time scale when the glacier changes sufficiently slowly then the derivative of volume with respect to area defines a thickness scale similar to that of johannesson and others and the time scale follows from it our version of the time scale is different from theirs because it explicitly includes the effect of surface elevation on mass balance rate which can cause a major increase in the time scale or even lead to unstable response the time constant has a dual role controlling both the rate and magnitude of response to a given climate change data from south cascade glacier washington u s a illustrate the ideas some of the difficulty in obtaining accurate values for the thickness and time scales and the susceptibility of all response models to potentially large errors

stable carbon isotope variations in northwest europe during the last glacial interglacial transition stable carbon isotope data that span part of the last glacial interglacial transition ca 14 9 ka 14c bp ca 15 11 ka cal bp and which derive from organ specific plant macrofossils recovered from two lake sediment profiles in the uk and one in norway are compared the recorded temporal variations show similar trends which over a millennial time scale appear to parallel the main drift in 18o as determined for the grip ice core it is postulated that some smaller scale variations in the 13c profiles may reflect the shorter term oscillations in 18o values evident in the grip record although this is less certain overall however the results suggest that stable carbon isotope measurements based on organ specific terrestrial plant macrofossils may provide i a means for establishing correlations between terrestrial successions and ii additional paleoenvironmental information as the apparent shadowing of the grip record indicates a common forcing mechanism for both greenland 18o and northwest european 13c variations from the evidence available we suggest that the recorded 13c variations reflect fluctuations in air temperature and or changes in water vapour pressure in the atmosphere 1997 john wiley sons ltd

decadal changes in tropical cyclone activity over the western north pacific in the late 1990s a pronounced decadal change in tropical cyclone tc activity over the western north pacific wnp in the late 1990s was identified based on a comparison of the two epochs that occurred before and after the late 1990s the tc genesis number exhibited an evident decrease over the southern wnp s wnp 5 20 n 105 170 e and an increase over the northern wnp n wnp 20 25 n 115 155 e which partly corresponded to a significant northward migration in the seasonal mean latitudinal location of tc genesis i e from 17 2 n to 18 7 n after the late 1990s the northwestward moving track became the most dominant track mode accompanied by the weakening of both the westward moving track and the northeastward recurving track meanwhile the tc occurrence frequency tcf experienced evident increases over southeastern china and the okinawa islands while prominent decreases occurred over the south china sea the philippine sea japan and east of japan changes in the tcf were determined by tc genesis changes tc track shifts and variations in regional tc durations which were all ascribed to the decadal change in tropical indo pacific sea surface temperature the full picture on the decadal changes in the wnp tc activity revealed in this study may provide useful guidance for regional tc seasonal forecasts and future projections

interdecadal changes in summertime typhoon tracks abstract the present work examines interdecadal variations of typhoon tracks in the western north pacific wnp during the boreal summer june september for the period 1951 2001 typhoon tracks are expressed as percentage values of the total number of typhoon passages into a 5 5 latitude longitude grid box with respect to the total number of typhoons formed in the wnp the analysis period is divided into two interdecadal periods id1 1951 79 and id2 1980 2001 from id1 to id2 typhoon passage frequency decreased significantly in the east china sea and philippine sea but increased slightly in the south china sea the time series of typhoon passage frequency over the east china sea and south china sea further reveal a regime shift in the late 1970s while those over the philippine sea indicate a continuous downward trend of 9 decade 1 the interdecadal changes in typhoon tracks are associated with the westward expansion of the subtropical northwestern pacific high snph in the late 1970s the e

tropical indian ocean influence on northwest pacific tropical cyclones in summer following strong el nino abstract in the summer following a strong el nino tropical cyclone tc number decreases over the northwest nw pacific despite little change in local sea surface temperature the authors analysis suggests el nino induced tropical indian ocean tio warming as the cause the tio warming forces a warm tropospheric kelvin wave that propagates into the western pacific inducing surface divergence off the equator the tropospheric kelvin wave suppresses convection and induces an anomalous anticyclone over the nw pacific both anomalies unfavorable for tcs the westerly vertical shear associated with the warm kelvin wave reduces the magnitude of vertical shear in the south china sea and strengthens it in the nw pacific an east west variation that causes tc activity to increase and decrease in respective regions these results help improve seasonal tc prediction

indian ocean capacitor effect on indo western pacific climate during the summer following el nino significant climate anomalies persist through the summer june august after el nino dissipates in spring over the equatorial pacific they include the tropical indian ocean tio sea surface temperature sst warming increased tropical tropospheric temperature an anomalous anticyclone over the subtropical northwest pacific and increased mei yu baiu rainfall over east asia the cause of these lingering el nino effects during summer is investigated using observations and an atmospheric general circulation model gcm the results herein indicate that the tio warming acts like a capacitor anchoring atmospheric anomalies over the indo western pacific oceans it causes tropospheric temperature to increase by a moist adiabatic adjustment in deep convection emanating a baroclinic kelvin wave into the pacific in the northwest pacific this equatorial kelvin wave induces northeasterly surface wind anomalies and the resultant divergence in the subtropics triggers suppressed convection and the anomalous anticyclone the gcm results support this kelvin wave induced ekman divergence mechanism in response to a prescribed sst increase over the tio the model simulates the kelvin wave with low pressure on the equator as well as suppressed convection and the anomalous anticyclone over the subtropical northwest pacific an additional experiment further indicates that the north indian ocean warming is most important for the kelvin wave and northwest pacific anticyclone a result corroborated by observations these results have important implications for the predictability of indo western pacific summer climate the spatial distribution and magnitude of the tio warming rather than simply whether there is an el nino in the preceding winter affect summer climate anomalies over the indo western pacific and east asia

the use of stable oxygen and carbon isotope stratigraphy as a dating tool abstract oxygen isotope stratigraphy in foraminifera from deep sea sediments provides a time series record of globally synchronous events with a resolution of a few thousand years for the quaternary despite deficiencies from problems of discerning local from global effects and from isotopic disequilibria and ecological effects oxygen isotope stratigraphy remains a highly powerful tool for dating and correlating deep sea sediments as well as for paleoclimatology in general oxygen isotope records per se do not provide absolute age control although carbon isotope records in some respects are more difficult to interpret than oxygen isotopes and are influenced by local factors such as biological productivity ocean ventilation rates and foraminiferal ecological factors carbon isotope records also reflect global phenomena they can therefore be utilized for correlation and dating purposes in a manner similar to oxygen isotope records and provide additional age control especially in areas where the oxygen isotope records may be influenced by temperature and low salinity overprints

glacier mass balance fluctuations in the pacific northwest and alaska usa the more than 40 year record of net and seasonal mass balance records from measurements made by the u s geological survey on south cascade glacier washington and wolverine and gulkana glaciers alaska show annual and interannual fluctuations that reflect changes in the controlling climatic conditions at regional and global scales as the mass balance record grows in length it is revealing significant changes in previously described glacier mass balance behavior and both inter glacier and glacier climate relationships south cascade and wolverine glaciers are strongly affected by the warm and wet maritime climate of the northeast pacific ocean their net balances have generally been controlled by winter accumulation with fluctuations that are strongly related to the pacific decadal oscillations pdo recently warm dry summers have begun to dominate the net balance of the two maritime glaciers with a weakening of the correlation between the winter balance fluctuations and the pdo non synchronous periods of positive and negative net balance for each glacier prior to 1989 were followed by a 1989 to 2004 period of synchronous and almost exclusively negative net balances that averaged 0 8 m for the three glaciers

interdecadal variability in tropical cyclone frequency over the south china sea and its association with the indian ocean sea surface temperature 1 during the period 1958 2001 the frequency of tropical cyclone tc genesis over the south china sea scs experienced an obvious interdecadal change around the mid 1970s compared to the period from late 1950s to early 1970s the number of tcs is significantly reduced during mid 1970s through late 1990s this interdecadal change in the tc frequency appears to relate to the increase in sea surface temperature sst of the tropical indian ocean the difference of the circulation between the warm phase and the cold phase of the tropical indian ocean sst provides support for the influence of the tropical indian ocean warming on the variability of the tc frequency over the scs in the warm phase lower level convergent and ascending flows over the tropical indian ocean are accompanied by upper level divergent flows part of which go toward the scs leading to upper level convergence and descent there consequently two lower level anticyclones develop and the tc genesis is suppressed over the scs

south cascade glacier mass balance 1935 2006 a simple model uses daily observations of precipitation and temperature at a nearby weather station to estimate glacier average seasonal mass balance components at south cascade glacier washington usa from 1935 24 years before measurements began at the glacier this is 13 years earlier than measurements that can be derived using the ncep ncar reanalysis database begins 1 january 1948 although the model s error in estimating winter balance and summer balance over 1959 2006 is greater than that of a model using the reanalysis database its error in estimating net balance is comparable the model uses an empirically determined precipita tion ratio between the station and the glacier and a seasonally varying temperature lapse rate de termined from 9 years of measurements at the glacier temperature is used with a degree day for mulation to estimate ablation and to partition precipitation between rain and snow for estimating accumulation both processes are assumed to exist throughout the year and model results are compared seasonally with adjusted observations of winter and summer balances the published mass balance series is adjusted to a constant topography 1970 series in an attempt to remove the influence of changing topography on the glacier s response to climate the reconstructed values prior to 1959 are also with respect to the 1970 glacier topography because precipitation is measured at the weather station rather than being inferred from other meteorological variables it enables us to distinguish more accurately between wet day and dry day conditions including vertical lapse rates of temperature

influence of upper air conditions on glaciers in scandinavia a simple model using once daily us national centers for environmental prediction us national center for atmospheric research ncep ncar re analysis upper air values estimates winter balance summer balance and net balance at ten glaciers in norway and two in sweden with 0 37 r 2 0 90 the october may arctic oscillation ao an index of sea level pressure slp in the northern hemisphere correlates with winter balance and net balance with 0 09 r 2 0 82 lower than the model in all but 3 of the 24 cases the october may north atlantic oscillation nao an slp gradient in the north atlantic has lower correlations than the ao for all but 5 of the 24 cases at all ten glaciers with records beginning before 1987 net balance became more positive after 1988 owing mainly to increased winter balance with summer balance changing little although winter temperatures increased they were still well below freezing so the rain snow division of the precipitation was only slightly affected increase in winter balance was due to increased precipitation caused by a change in atmospheric circulation resulting in more frequent westerly flow concurrent with the warming at 850 hpa westerly flow is 2 5 c warmer than easterly flow westerly flow warmed by 0 3 c easterly by 0 7 c both the ao and nao with which winter balance is positively correlated at all 12 glaciers were more positive after 1988

using upper air conditions to estimate south cascade glacier washington u s a summer balance asimplemodelusesonce dailymeteorologicalvaluesintheu s national centers for environmental predictionand u s national center foratmospheric research ncep ncar re analysis databaseto estimate summerbalanceof south cascade glacier washington u s a each year over1959 99 the rms error 0 30mw e r 2 0 71 is com parable to measurement error the model relates summer balance linearly to temperature t 0 c at 2000m and to snow flux at1650m the altitudes in recent years of the equilib rium line and terminus the snow flux is the product of the humidity and westerly wind component at 850hpa when temperature t 2 c at 1650m temperatures are inter polated linearly betweenthe 850 and 700hpa levels boththe positive 2000mtemperature andthe snow flux are summedfrom 26 aprilto 4 october whenthe summerestimatesare combinedwiththosefromawinterbalancemodelusingthesamedatabase thermserrorin estimating netbalance is 0 40m r 2 0 81 the indicated sensitivities of balance to warm ing of 1 c are 0 51m for summerand 0 24m for winter onthe assumptionthatthetotal 0 75m c 1 sensitivityexists atall altitudes awarmingof only 0 7 c wouldbe sufficientto overcome the1986 98 averagenetbalance 0 5matthe top of theglacier

static mass balance sensitivity of arctic glaciers and ice caps using a degree day approach the purpose of this study is to enhance our understanding of the response of glaciers to climate change global sea level is affected by changes in glacier ice volume and melt water from glaciers is a principal water source in many regions this study applies glacier mass balance modelling with varying complexity and spatial resolution ranging from individual glaciers to regional and global assessments of glacier mass losses glaciers located in maritime environments generally show considerably higher mass balance sensitivities than those in continental settings on average an assumed increase in annual precipitation of 10 tends to offset the effect of an annual temperature change of 1 k by roughly 20 two case studies at storglaciaren sweden and hofsjokull iceland involve model results of future mass balance change and glacier melt induced changes in runoff applying a temperature and precipitation scenario for iceland in 2050 results in increased total runoff from hofsjokull by roughly one third and results emphasize the role of the firn layer in delaying water flow through glaciers yielding a redistribution of discharge within the year based on a global gridded data set of glacierized area the sea level equivalent from all mountain glaciers and ice caps outside the ice sheets in greenland and antarctica during 1961 2004 caused by changes in temperature and precipitation is estimated to be 0 58 0 34 mm a 1 the mountain glaciers and ice caps around antarctica alone contribute almost 40 of the global estimate and hence their contribution is considerably larger than previously assumed

interpreting paleoclimate from l8o and 2h in plant cellulose comparison with evidence from fossil insects and relict permafrost in southwestern ontario the oxygen isotope content of terrestrial plant cellulose is related to that of the source waters by a two step process involving evapotranspirative leaf water enrichment and equilibrium isotopic exchange between leaf water and atmospheric carbon dioxide a combination of two models that describe these steps yields consistent agreement between measured and predicted climatic and isotopic data humidity is the dominant influence on variations in the cellulose 18o enrichment relative to the source water a good first order approximation of the average daytime relative humidity during the growth season at a site can be based on the linear correlation that exists between humidity and cellulose enrichment without explicit consideration of factors such as temperature 18o of atmospheric vapour and leaf boundary layer dynamics the value of the combined model for paleoclimatic reconstruction has been tested using fossil wood from a late glacial site at brampton ontario estimates of the past relative humidity

surface temperature lapse rates over complex terrain lessons from the cascade mountains lapse rates of 3 9 5 2 c km 1 substantially smaller than the often assumed 6 5 c km 1 the data sets show similar seasonal and diurnal variability with lapse rates smallest 2 5 3 5 c km 1 in late summer minimum temperatures and largest 6 5 7 5 c km 1 in spring maximum temperatures geographic windward versus lee side differences in lapse rates are found to be substantial using a simple runoff model we show the appreciable implications of these results for hydrological modeling

paleoclimate reconstruction of the prince creek formation arctic alaska during maastrichtian global warming abstract the upper cretaceous maastrichtian prince creek formation of arctic alaska 82 85 n paleolatitude preserves successions of alluvial paleosols that are used to estimate mean annual precipitation map mean annual temperature mat and meteoric water oxygen isotope composition for the prince creek formation the highest map estimates range between 1000 and 3900 mm yr and the lowest range between 350 and 1200 mm yr the precipitation variability derived from stable carbon isotope analysis occurs on a time scale of 104 years map values agree with previous interpretations from fossil pollen pedological features soil types vegetation composition sedimentological indicators and clamp estimates that suggest high precipitation amounts and high humidity despite the considerable uncertainty with mat proxies our values are consistent with warm month mean temperatures obtained previously from paleobotanical data the 18o of smectite from bentonite beds clusters around 5 0 vsmow the 18o of meteoric water calculated from bentonitic smectite is 23 vsmow assuming a mean annual temperature of 6 3 c which is slightly more 18o depleted than meteoric water calculated from pedogenic siderite in stratigraphically younger beds closer to the brooks range chronostratigraphic correlation with the lower cantwell formation denali national park alaska 64 n paleolatitude suggests higher precipitation rates and highly 18o depleted precipitation in the late cretaceous paleo arctic compared to central alaska these data are consistent with previous studies that suggest a warmer and moister greenhouse earth and an intensified hydrological cycle that enhanced latent heat transport resulting in increased rainout effects

upper air model of summer balance on mount rainier usa in 2003 07 summer balance was measured at altitudes between 1700 and 3382 m a s l on two glaciers on mount rainier washington state usa 46 85 n 121 72 w 4400 m a s l south facing nisqually glacier and east northeast facing emmons glacier upper air temperatures at the nearest gridpoint in the ncep ncar reanalysis database are used in a distributed over altitude positive degree day pdd model for each glacier the model used the same coefficients at all altitudes for all years the rms model error was 0 65 r 2 0 87 and 0 78 m a 1 w e r 2 0 93 for nisqually and emmons glaciers respectively although pdd work generally uses different coefficients for snow and ice surfaces and the duration of exposure of those surfaces varies with altitude error in this single coefficient model is nearly uncorrelated with altitude values of coefficients obtained are within the range of those found in other pdd work the degree day coefficient however differs markedly between the two glaciers and is shown to be controlled by the difference between them in vertical gradient of measured summer balance it is smaller for nisqually glacier where solar radiation is a stronger contributor to melt and larger for emmons glacier where it is a weaker contributor over 1948 2007 when the model calibrated over 2003 07 was applied to the upper air temperatures estimated summer balance was 0 4 m a 1 less negative over 1962 83 than before and 0 6 m a 1 less negative than after corresponding roughly with changes of the northeast pacific sea surface temperatures

the little ice age as recorded in the stratigraphy of the tropical quelccaya ice cap the analyses of two ice cores from a southern tropical ice cap provide a record of climatic conditions over 1000 years for a region where other proxy records are nearly absent annual variations in visible dust layers oxygen isotopes microparticle concentrations conductivity and identification of the historical a d 1600 huaynaputina ash permit accurate dating and time scale verification the fact that the little ice age about a d 1500 to 1900 stands out as a significant climatic event in the oxygen isotope and electrical conductivity records confirms the worldwide character of this event

sensitivity of mass balance of five swiss glaciers to temperature changes assessed by tuning a degree day model a degree day model is used to assess the sensitivity of the mass balance of five swiss glaciers to temperature changes the model uses temperature data extrapolated from nearby climate stations and is tuned by varying precipitation to make the model fit the observed distribution of mass balance with altitude once the model is tuned the effect of temperature change is simulated by recalculating the mass balance with the same parameters as before but with a temperature increase of 1 c throughout the year the largest mass balance changes involving increased ablation of 1 m w e a 1 c 1 occur at the snout with a progressively smaller increase with altitude the area averaged sensitivities for the five glaciers are 0 7 to 0 9 m w e a 1 c 1 if annual precipitation also increased by 20 it would partly offset the effect of the 1 c higher temperatures but could not compensate for it

quantifying the effects of climate and surface change on glacier mass balance when a mass balance is computed using an outdated map that computation does not reveal the actual mass change but older maps often must be used for practical reasons we present a method by which with a few additional measurements each year a mass balance computed with an outdated map can be transformed into an actual mass change this is done by taking into account the influence of changes in areal extent and changes in the surface elevation of the glacier since the map was made this method is applied to south cascade glacier washington u s a as an example the computed cumulative mass balance from 1970 to 1997 would have been 16 too negative if the 1970 map had not been updated while the actual volume change of a glacier is relevant to hydrological studies the change that would have occurred on a constant or static surface is more relevant to certain glacier dynamics problems and most climate problems we term this the reference surface balance and propose that such a balance which deliberately omits the influence of changes in area and surface elevation is better correlated to climatic variations than the conventional one which incorporates those influences

preparation of pollen for stable carbon isotope analyses abstract differential diagenesis of the chemical components of pollen in sub fossil records necessitates the isolation of a single resistant chemical component of pollen prior to its isotopic analysis as sporopollenin is particularly resistant to diagenesis and comprises typically 65 80 of the pollen grain it is a suitable component for this purpose conventional acetylation methods of pollen preparation for palynological studies are reliant on the use of carbon bearing compounds which introduce large errors to the pollen carbon isotopic composition 13 c we present results from a novel non carbon containing acid extraction technique to isolate sporopollenin using this technique we demonstrate that the 13 c signals in raw and processed pollen are highly correlated but display an offset associated with the non sporopollenin components

an interdecadal change in southern china summer rainfall around 1992 93 the present study documents a pronounced interdecadal change in summer rainfall over southern china around 1992 93 and explores the plausible reasons for this change the summer rainfall is persistently below normal during 1980 92 and above normal during 1993 2002 coherent changes in atmospheric circulation are identified over east asia and the south china sea scs western north pacific wnp the increase in rainfall is accompanied by an increase in lower level convergence midtropospheric ascent and upperlevel divergence over southern china the changes in lower level winds feature two anomalous anticyclones one over the scs subtropical wnp and the other over north china mongolia the outflows from the two anomalous anticyclones converge over southern china leading to anomalous moisture convergence enhanced ascent and increased rainfall the development of the northern anticyclone is related to an increase in the tibetan plateau snow cover in the preceding winter spring that leads to a contrast in temperature change between the plateau and the surrounding regions the relatively small temperature change over the plateau coupled with increases in temperature to the west and the east leads to an increase in surface pressure extending northward from the plateau the development of the southern anticyclone is related to an increase in sea surface temperature in the equatorial indian ocean that enhances lower level convergence and ascent the accompanying upper level divergent flows from the tropical indian ocean to the scs wnp lead to the development of anomalous descent and lower level anomalous anticyclone over the scs wnp

surface mass balance thinning and iceberg production columbia glacier alaska 1948 2007 a mass balance model using upper air meteorological data for input was calibrated with surface mass balance measured mainly during 1977 78 at 67 sites on columbia glacier alaska between 135 and 2645 m a s l root mean square error model vs measured is 1 0 m w e a 1 w ithr 2 0 88 a remarkable result of the analysis was that both precipitation and the factor in the positive degree day model used to estimate surface ablation were constant with altitude the model was applied to reconstruct glacier wide components of surface mass balance over 1948 2007 surface ablation 4k m 3 ice eq a 1 ice equivalent has changed little throughout the period from 1948 until about 1981 when drastic retreat began the surface mass balance was positive but changes in glacier geometry were small so the positive balance was offset by calving 0 9 km 3 ice eq a 1 during retreat volume loss of the glacier accounted for 92 of the iceberg production calving increased to 4 3 km 3 ice eq a 1 from 1982 to 1995 and after that until 2007 to 8 0 km 3 ice eq a 1 which was about twice the loss by surface ablation whereas prior to retreat it was only about a quarter as much calving is calculated as the difference between glacier wide surface mass balance and geodetically determined volume change

in phase transition from the winter monsoon to the summer monsoon over east asia role of the indian ocean 1 analysis of observations shows that the weak east asian winter monsoon eawm to weak east asian summer monsoon easm transitions mainly occur in el nino decaying years whereas strong eawm denoting stronger northerly winds along east asian coast to strong easm denoting less precipitation along the meiyu baiu rainband transitions all occur in non el nino southern oscillation enso years during the period 1979 2009 this new finding implies that enso is not indispensable to the in phase eawm to the easm transitions the present study reveals an important role of the indian ocean in the strong eawm to strong easm transitions and proposes a possible mechanism for these transitions a strong eawm induces more precipitation over the maritime continent and the associated anomalous heating excites a gill matsuno type pattern in the tropics the resultant wind and cloud changes enhance latent heat flux and reduce downward shortwave radiation over the northwestern indian ocean in winter which leads to sst cooling the cold sst anomalies persist to summer and excite an anomalous cyclone over the subtropical western north pacific leading to a strong easm the above processes also operate in the weak eawm to weak easm transitions during which el nino impacts dominate but with additional contributions from the eawm the results of observational analysis are confirmed by numerical experiments with a coupled model

the abrupt shift of typhoon activity in the vicinity of taiwan and its association with western north pacific east asian climate change bayesian analysis is applied to detect changepoints in the time series of seasonal typhoon counts in the vicinity of taiwan an abrupt shift in the typhoon count series occurs in 2000 on average 3 3 typhoons per year have been noted before 2000 1970 99 with the rate increasing to 5 7 typhoons per year since 2000 2000 06 this abrupt change is consistent with a northward shift of the typhoon track over the western north pacific east asian region and an increase of typhoon frequency over the taiwan east china sea region the northward shift of the typhoon track tends to be associated with typhoon enhancing environmental conditions over the western north pacific namely the weakening of the western north pacific subtropical high the strengthening of the asian summer monsoon trough and the enhanced positive vorticity anomalies in the lower troposphere based on observational analysis and model simulations warm sea surface temperature anomalies over the equatorial western and central pacific appear to be a major factor contributing to a northward shifted typhoon track

estimating south cascade glacier washington u s a mass balance from a distant radiosonde and comparison with blue glacier a simple flux model using twice daily measurements of wind humid ity and temperature from standard upper air levels in a distant radiosonde estimated winter balance of south cascade glacier over 1959 98 with error 0 24 m w e correla tion between net and winter balance is strong the model estimates net balance with error 0 53 m w e over the past 40 years average net balance of south cascade glacier has been strongly negative 0 46 m w e and it has been shrinking steadily in com parison 200 km wsw at blue glacier the average balance has been less negative 0 13 m w e that glacier has undergone little change over the 40 years balance histories of the two glaciers are positively correlated r 0 54 and south cascade has been more out of balance than blue presumably because it is still adjusting to climate change since the little ice age recent warming and drying has made the net balance of both glaciers strongly negative since 1976 0 84 m w e at south cascade 0 56 m w e at blue if south cascade glacier were in balance with the 1986 1998 climate it would be about 1 4 of its present area if conditions persist retreat of both glaciers is inevitable

kinetic energy budget during the genesis period of tropical cyclone durian 2001 in the south china sea abstracta set of kinetic energy ke budget equations associated with four horizontal flow components was derived to study the ke characteristics during the genesis of tropical cyclone tc durian 2001 in the south china sea using numerical simulation data the genesis process was divided into three stages the monsoon trough stage stage 1 the midlevel mesoscale convective vortex mcv stage stage 2 and the establishment stage of the tc vortex stage 3 analysis showed that the ke of the symmetric rotational flow srf was the largest and kept increasing especially in stages 2 and 3 representing the symmetrization process during tc genesis the ke of the srf was mainly converted from the ke of the symmetric divergent flow sdf largely transformed from the available potential energy ape it was found that vortical hot towers vhts emerged abundantly aggregated and merged within the mcv region in stages 1 and 2 from the energy budget perspective massive moist convection produced latent h

a new approach for reconstruction of the holocene climate in the mongolian altai the high resolution δ13c records of toc and pollen complexes in hoton nur lake sediments abstract 13 c of total organic carbon toc and pollen grain toc c n ratio and 15 n of total organic nitrogen ton in a 2 57 m long core from hoton nur lake in mongolian altai have been measured for reconstruction of the holocene climates the 13 c values of toc and pollen carbon have similar average values but different ranges pollen 13 c has negative correlation with ap arboreal taxa pollen and positive correlation with nap herbaceous pollen and spores that are connected with conditions of humidity in the area taiga biome has lighter 13 c than steppe biome hence pollen 13 c composition is more sensitive to changes of humidity in the analogous spectra than palynotaxonomical structure and 13 c of toc based on our results the holocene climates in mongolian altai are 1 dry conditions prior to 11 5 kyr bp 2 wet conditions between 11 5 and 6 0 kyr bp 3 a relatively dry cool episode during 6 4 kyr bp 4 stable cool and semiarid conditions with moderately effective moisture during the past 4000 years two abrupt climatic changes occurred at 7 45 kyr bp and 11 5 kyr bp might be related to glacial activities the holocene climatic trend in mongolian altai which is controlled by the westerlies is similar to the trend of monsoonal climate shown by the chinese speleothem records as well as the lake sand dune evidence in the deserts of nw china the contact of the two climatic systems and shift of the monsoonal boundary during the past need to be further studied

impact of the indian ocean sst basin mode on the asian summer monsoon 1 following an el nino event a basin wide warming takes place over the tropical indian ocean peaks in late boreal winter and early spring and persists through boreal summer our observational analysis suggests that this indian ocean warming induces robust climatic anomalies in the summer indo west pacific region prolonging the el nino s influence after tropical east pacific sea surface temperature has returned to normal in response to the indian ocean warming precipitation increases over most of the basin forcing a matsuno gill pattern in the upper troposphere with a strengthened south asian high near the ground the southwest monsoon intensifies over the arabian sea and weakens over the south china and philippine seas an anomalous anticyclonic circulation forms over the subtropical northwest pacific collocated with negative precipitation anomalies all these anomaly patterns are reproduced in a coupled model simulation initialized with a warming in the tropical indian ocean mixed layer indicating that the indian ocean warming is not just a passive response to el nino but important for summer climate variability in the indo west pacific region the implications for seasonal prediction are discussed