after six decades of monitoring glacier mass balance we still need data but it should be richer data this paper reviews data on glacier mass balance together with extra metadata on topography and climate to put the data into context the 2007 intergovernmental panel on climate change ipcc estimates of global average glacier mass balance may not be much different from simple averages a more mathematically correct approach is to analyse long and continuous mass balance series measured in different regions but there are few long series and they do not cover the globe in any representative way however 30 year series from 30 glaciers confirm a recent 1996 2005 trend to very negative mass balance after two decades of nearly zero mass balance climate data from a global gridded climatology are applied to datasets for global glacier cover for 318 glaciers with mass balance data for at least 1 year and for 30 glaciers with 30 year series of measurements results show that mean precipitation is relatively low in the global glacier cover dataset and much higher for the observed glaciers this shows that current mass balance measurements are biased towards wetter conditions than are typical for global glacier cover we urgently need to find better ways of analysing sparse datasets with complex spatial and temporal patterns like the present mass balance dataset

tropical sst forcing on the anomalous wnp subtropical high during july august 2010 and the record high sst in the tropical atlantic in summer of 2010 the western north pacific subtropical high wnpsh was extremely strong and exhibited unusual westward extension which resulted in record breaking warmth in japan and considerably below normal and westward shifted tropical cyclone activity in the western north pacific wnp although a moderate la nina occurred the sea surface temperature sst in the northern indian ocean nio and tropical atlantic ta was considerably high in this study we argued that the la nina cold sst alone was not sufficient to maintain the strong wnpsh of 2010 and that the unusually warm ssts in the nio and ta markedly contributed to the enhancement and westward shift of the wnpsh in the boreal summer of that year we focused on the effects of sea surface temperature anomalies in the tropical atlantic ta sstas which have been seldom explored and are poorly understood compared with the effects of sstas in the tropical pacific and nio the warm ta sst forced a westward extending overturning circulation with a sinking branch over the central pacific ocean which produced a remote response similar to the la nina condition and enhanced the wnpsh the warm ta sst also induced the cyclonic anomaly in the tropical eastern north pacific a distinct phenomenon not observed in a canonical la nina event furthermore we demonstrated that the anomalous near surface circulation associated with the negative north atlantic oscillation might play a more dominant role than that of the 2009 el nino in inducing the record high sst in the ta in 2010

observations and modeling of strong ground motions for the 9 october 1995 mw 8 colima jalisco mexico earthquake abstract the colima jalisco cj region in northwestern mexico has generated large magnitude earthquakes at least since 1800 for example during the last century three large destructive shallow thrust subduction earthquakes occurred on 3 and 18 june 1932 with m s of 8 2 and 8 respectively and on 9 october 1995 m w 8 m s 7 4 this historical seismicity and the lack of seismic recordings in the cj region pose important constraints for the computation of reliable seismic hazard studies for sites in this region of mexico towards this aim we have used a hybrid method to generate broadband bb synthetics for the m w 8 cj 1995 earthquake for the recording sites of the near mz intermediate cg and far col fields the low frequency lf 0 5 hz synthetics were simulated by applying a 3d finite difference method and the high frequencies hf 0 5 hz were generated by the empirical green s function technique finally matched filters were applied to the lf and hf synthetics to obtain the bb time series the lf synthetics were computed from a finite fault description of the source with four asperities in a 2 5d model constrained by gravity and seismological data our preferred model includes an approximation of a thin accretionary prism for the hf modeling we also used the four asperity source model as well as the recordings of the foreshock and aftershock of the m w 8 1995 mainshock based on the comparisons of the bb synthetics with the observed strong ground motions for the 1995 cj earthquake at the three stations we believe that our hybrid method is a first step toward the generation of more reliable estimates of the seismic hazards in cj region further improvement in the hazard estimates depends on the urgent deployment of seismological and strong ground motion infrastructure in the cj region

measurement and parameterization of albedo variations at haut glacier d arolla switzerland spatial and temporal variations of surface albedo on haut glacier d arolla switzerland during the 1993 and 1994 ablation seasons are described correlation and regression analyses are used to explain the albedo variations in terms of independent meteorological and surface property variables parameterizations are developed which allow estimation of albedo variation in surface energy balance models snow albedo is best estimated from accumulated daily maximum temperatures since snowfall on deep snow 0 5 cm w e depth a logarithmic function is used while on shallow snow 0 5 cm w e depth an exponential function is used to enable the albedo to decay to the underlying ice or debris albedo the transition from deep to shallow snow is calculated as a function of decreasing snow depth combined r 2 0 65 this new parameterization performs better than earlier schemes because accumulated daily maximum temperatures since snowfall correlate strongly with snow grain size and impurity concentration the main physical controls on snow albedo ice albedo may be parameterized by its relationship to elevation r 2 0 28 but this approach results in only a small improvement over the assumption of a constant mean ice albedo

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

suitability of a constant air temperature lapse rate over an alpine glacier testing the greuell and bohm model as an alternative near surface air temperature typically measured at a height of 2 m is the most important control on the energy exchange and the melt rate at a snow or ice surface it is distributed in a simplistic manner in most glacier melt models by using constant linear lapse rates which poorly represent the actual spatial and temporal variability of air temperature in this paper we test a simple thermodynamic model proposed by greuell and bohm in 1998 as an alternative using a new dataset of air temperature measurements from along the flowline of haut glacier d arolla switzerland the unmodified model performs little better than assuming a constant linear lapse rate when modified to allow the ratio of the boundary layer height to the bulk heat transfer coefficient to vary along the flowline the model matches measured air temperatures better and a further reduction of the root mean square error is obtained although there is still considerable scope for improvement the modified model is shown to perform best under conditions favourable to the development of katabatic winds few clouds positive ambient air temperature limited influence of synoptic or valley winds and a long fetch but its performance is poor under cloudy conditions

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

interannual and interdecadal variability of the summertime western north pacific subtropical high 1 the western north pacific subtropical high wnpsh in summer exhibits significant 2 3 years and 3 5 years oscillations with interdecadal variability the 2 3 year oscillation is most evident after 1990 it is accompanied by anomalous meridional overturning circulation characterized by warm sst anomalies ssta and ascending motion in the maritime continent and anomalous descending motion near the philippine sea and by evolving warm to cold ssta in the central eastern pacific from the preceding winter to the summer the 3 5 year oscillation is most pronounced during the 1980s it is accompanied by anomalous descending motion over the maritime continent and warm ssta in the central eastern equatorial pacific that persists from the preceding winter to the summer the complementary cooling and descending motion in the western pacific are related to anomalous east west circulation associated with enso

transmission of solar radiation through clouds on melting glaciers a comparison of parameterizations and their impact on melt modelling we explore the robustness and transferability of parameterizations of cloud radiative forcing used in glacier melt models at two sites in the swiss alps we also look at the rationale behind some of the most commonly used approaches and explore the relationship between cloud transmittance and several standard meteorological variables the 2 m air temperature diurnal range is the best predictor of variations in cloud transmittance however linear and exponential parameterizations can only explain 30 50 of the observed variance in computed cloud transmittance factors we examine the impact of modelled cloud transmittance factors on both solar radiation and ablation rates computed with an enhanced temperature index model the melt model performance decreases when modelled radiation is used the reduction being due to an underestimation of incoming solar radiation on clear sky days the model works well under overcast conditions we also seek alternatives to the use of in situ ground data however outputs from an atmospheric model 2 2 km horizontal resolution do not seem to provide an alternative to the parameterizations of cloud radiative forcing based on observations of air temperature at glacier automatic weather stations conversely the correct definition of overcast conditions is important

connection between the decadal variability in the southern ocean circulation and the southern annular mode previous studies demonstrated the remarkable upward trend of the southern annular mode sam and southern ocean wind stress in association with anthropogenic forcing an oceanic reanalysis data set is used to investigate the response of the circulation in the southern ocean to the decadal variability of sam our results indicate the strengthening and the poleward shift of the northward ekman velocity as well as the ekman pumping rate which led to a corresponding strengthening trend in the deacon cell this strengthening in turn intensified the meridional density gradient and the tilting of the isopycnal surfaces on the interannual time scale the antarctic circumpolar currents acc transport exhibits a positive correlation with sam index as seen separately in observations however there is no significant trend in the total transport of acc possible reasons are discussed

wave guide effects in subduction zones evidence from three dimensional modeling we have simulated seismic wave propagation in models of the subduction zone off the pacific coast of mexico using a three dimensional finite difference method the results show that a significant part of the energy generated by earthquakes in the subduction zone can be trapped inside a wave guide generated by the low velocity material of the accretionary prism the trapped waves in the simulations appear as long duration wave trains that follow the onset of the surface waves similar to the signature of broadband seismograms recorded by stations along the pacific coast of mexico for subduction earthquakes

the a d 1567 mw 7 2 ameca jalisco earthquake western trans mexican volcanic belt surface rupture parameters seismogeological effects and macroseismic intensities from historical sources the a d 1567 ameca jalisco earthquake west central mexico is the strongest known historical crustal earthquake in the trans mexican volcanic belt an active volcanic arc being deformed by an intra arc extensional fault network the location of the surface rupture at the base of the sierra de ameca mountain range its length 13 14 leagues 54 59 km and the scarp height 1 2 estados 1 67 3 34 m are inferred from the description of this earthquake in the relacion de ameca of 1579 which contains what is probably the earliest documentation of an earthquake surface rupture in the americas from scaling relations the moment magnitude of this earthquake can be estimated as 7 2 0 3 based on the rupture length the a d 1567 ameca earthquake is likely to have ruptured to the surface along two or all three major segments of the ameca san marcos normal fault system online material excerpts from five historical documents related to the 1567 ameca earthquake

seismotectonic constraints on the convergence rate between the rivera and north american plates there are two significantly different types of models for the convergence rate between the rivera and north american plates the first type the high rate model bandy 1992 predicts convergence rates of approximately 5 0 cm yr near the southern end of the rivera north america subduction zone and between 2 0 and 3 0 cm yr at its northern end in contrast the second type the low rate model e g demets and stein 1990 predicts convergence rates of between 2 0 and 3 3 cm yr near the southern end of the rivera north america subduction zone and between 0 6 and 1 7 cm yr at its northern end seismotectonic relationships which relate seismic characteristics of subduction zones maximum magnitudes maximum seismic depths etc to plate tectonic parameters convergence rates age of the oceanic lithosphere etc provide a means of distinguishing between the two different models three such relationships suggest that the rivera north american and cocos north american convergence rates should be roughly equal across the rivera cocos plate boundary favoring the high rate model employing the high rate model one can evaluate the magnitude and distribution of the strike slip component of forearc motion vss produced by oblique convergence between the rivera and north american plates the analysis indicates both a progressive increase and clockwise reorientation of vss northwestward along the plate contact zone of the rivera north america subduction zone such a distribution in vss should produce a northwestward movement of and nw se oriented extension within the interior of the jalisco block consistent with previous proposals of jalisco block motions also such a distribution in vss should produce a slight clockwise rotation of the jalisco block in the vicinity of bahia de banderas consistent with paleomagnetic data

temperature and precipitation climate at the equilibrium line altitude of glaciers expressed by the degree day factor for melting snow several authors relate accumulation or precipitation at the glacier equilibrium line altitude ela to summer mean temperature using exponential or power law functions i analyze the accumulation temperature relation at the ela with a degree day model using data from the 1992 paper by a ohmura and others the dataset includes estimates at the ela of winter balance and of winter balance plus summer precipitation which represent respectively low and high estimates of annual accumulation which is seldom measured the ohmura dataset only lists summer mean temperature but i recover monthly temperatures for the whole year for 66 of the glaciers by assuming sinusoidal temperature variation through the year and using annual temperature range from a gridded climatology monthly degree day sums are then estimated from monthly mean temperature and summed to give annual totals so degree day factors for melting snow at the ela are obtained the degree day factors fall close to those reported in the literature for glacier snowmelt with averages of 3 5 1 4 and 4 6 1 4 mm d 1 k 1 for low and high accumulation estimates on the 66 glaciers the degree day model gives a family of accumulation temperature curves that depend upon the annual temperature range representing the contrast between maritime and continental climates

interannual and interdecadal variations of the east asian summer monsoon and tropical pacific ssts part i roles of the subtropical ridge the interannual relationship between the east asian summer monsoon and the tropical pacific ssts is studied using rainfall data in the yangtze river valley and the ncep reanalysis for 1951 96 the datasets are also partitioned into two periods 1951 77 and 1978 96 to study the interdecadal variations of this relationship a wet summer monsoon is preceded by a warm equatorial eastern pacific in the previous winter and followed by a cold equatorial eastern pacific in the following fall this relationship involves primarily the rainfall during the pre mei yu mei yu season may june but not the post mei yu season july august in a wet monsoon year the western north pacific subtropical ridge is stronger as a result of positive feedback that involves the anomalous hadley and walker circulations an atmospheric rossby wave response to the western pacific complementary cooling and the evaporation wind feedback this ridge extends farther to the west from the previous winter to the following fall resulting in an 850 hpa anomalous anticyclone near the southeast coast of china this anticyclone 1 blocks the pre mei yu and mei yu fronts from moving southward thereby extending the time that the fronts produce stationary rainfall 2 enhances the pressure gradient to its northwest resulting in a more intense front and 3 induces anomalous warming of the south china sea surface through increased downwelling which leads to a higher moisture supply to the rain area a positive feedback from the strong monsoon rainfall also appears to occur leading to an intensified anomalous anticyclone near the monsoon region this sst subtropical ridge monsoon rainfall relationship is observed in both the interannual timescale within each interdecadal period and in the interdecadal scale the sst anomalies sstas change sign in northern spring and resemble a tropospheric biennial oscillation tbo pattern during the first interdecadal period 1951 77 in the second interdecadal period 1978 96 the sign change occurs in northern fall and the tbo pattern in the equatorial eastern pacific sst is replaced by longer timescales this interdecadal variation of the monsoon sst relationship results from the interdecadal change of the background state of the coupled ocean atmosphere system this difference gives rise to the different degrees of importance of the feedback from the anomalous circulations near the monsoon region to the equatorial eastern pacific in a wet monsoon year the anomalous easterly winds south of the monsoon enhanced anomalous anticyclone start to propagate slowly eastward toward the eastern pacific in may and june apparently as a result of an atmosphere ocean coupled wave motion these anomalous easterlies carry with them a cooling effect on the ocean surface in 1951 77 this effect is insignificant as the equatorial eastern pacific sstas already change from warm to cold in northern spring probably as a result of negative feedback processes discussed in enso mechanisms in 1978 96 the equatorial eastern pacific has a warmer mean sst a stronger positive feedback between ssta and the walker circulation during a warm phase tends to keep the ssta warm until northern fall when the eastward propagating anomalous easterly winds reach the eastern pacific and reverse the ssta

distributed mass balance modelling on two neighbouring glaciers in ortles cevedale italy from 2004 to 2009 a 6 year application of an enhanced temperature index mass balance model to careser and la mare glaciers eastern italian alps is presented the two glaciers exhibit very different characteristics and a comprehensive dataset of distributed mass balance measurements was used to test the model performance the model was run using meteorological data acquired outside the glaciers the work was focused on two main aspects 1 the development of a morphological redistribution procedure for snow and 2 the comparison of three different melt algorithms proposed in the literature the results show that the simple method proposed for snow redistribution can greatly improve simulation of winter balance and further improvements would be achievable by collecting data on inaccessible and high altitude areas all three melt formulations displayed a good skill level and very similar results in modelling the mass balance distribution over glacier areas with slightly better results from a multiplicative algorithm in capturing the vertical balance gradient the simulation errors are related to aspect and elevation and tend to be spatially aggregated some assumptions concerning the spatial and temporal distribution of air temperature and incoming solar radiation although reasonable and widely used in the literature may be responsible for this aggregation hence there is a need to further investigate the processes that regulate the distribution of melt energy and that appear to control the current deglaciation phase in this area

northern east pacific rise magnetic anomaly and bathymetric framework the oceanic crust in the eastern pacific between 7on and 30on and east of 127ow contains a fairly complete history of the spreading centers associated with the east pacific rise since 25 m y b p late oligocene in this paper we have summarized the seafloor spreading magnetic anomaly data and the bathymetric data that reflect the record of this tectonic history the well defined magnetic lineations north of the clarion fracture zone in the mouth of the gulf of california and on the east flank of the east pacific rise epr are carefully examined and used to provide a guide for interpreting the spreading pattern between the clarion and clipperton fracture zones southward of the rivera fracture zone over the mathematician ridge and over the entire epr east of the mathematician ridge between the rivera and siqueiros fracture zones the bathymetric data provide a trace of the fracture zone pattern in each of the above mentioned areas the fracture zone bathymetry and the seafloor spreading magnetic lineations on the epr south of the rivera fracture zone have a distinctive fanning pattern caused by close poles of rotation and plate boundary reorganizations all these data provide a good record of the plate reorganizations in the middle miocene at magnetic anomaly 5a time 12 5 to 11 m y b p in the late miocene at magnetic anomaly 3 4 time 6 5 m y b p and in the pliocene at magnetic anomaly 2 3 time 3 5 m y b p several abandoned spreading centers including the mathematician ridge were left behind as a result of these reorganizations the mathematician ridge is shown to be a set of ridges and trough whose origin is related to the tectonic activity associated with each of the above mentioned reorganizations since anomaly 5a

re emerging ocean temperature anomalies in late 2010 associated with a repeat negative nao northern europe was influenced by consecutive episodes of extreme winter weather at the start and end of the 2010 calendar year a tripole pattern in north atlantic sea surface temperature anomalies sstas associated with an exceptionally negative phase of the north atlantic oscillation nao characterized both winter periods this pattern was largely absent at the surface during the 2010 summer season however equivalent sub surface temperature anomalies were preserved within the seasonal thermocline throughout the year here we present evidence for the re emergence of late winter 2009 10 sstas during the following early winter season of 2010 11 the observed re emergence contributes toward the winter to winter persistence of the anomalous tripole pattern considering the active influence of the oceans upon leading modes of atmospheric circulation over seasonal timescales associated with the memory of large scale sea surface temperature anomaly patterns the re emergence of remnant temperature anomalies may have also contributed toward the persistence of a negative winter nao and the recurrence of extreme wintry conditions over the initial 2010 11 winter season

three dimensional simulation of a magnitude 7 75 earthquake on the san andreas fault simulation of 2 minutes of long period ground motion in the los angeles area with the use of a three dimensional finite difference method on a parallel supercomputer provides an estimate of the seismic hazard from a magnitude 7 75 earthquake along the 170 kilometer section of the san andreas fault between tejon pass and san bernardino maximum ground velocities are predicted to occur near the fault 2 5 meters per second and in the los angeles basin 1 4 meters per second where large amplitude surface waves prolong shaking for more than 60 seconds simulated spectral amplitudes for some regions within the los angeles basin are up to 10 times larger than those at sites outside the basin at similar distances from the san andreas fault

simulating strong motions of large earthquakes using recordings of small earthquakes the loma prieta mainshock as a test case abstract a simple method is developed for predicting ground motions for future large earthquakes for specific sites by summing and filtering recordings of adjacent small earthquakes this method is tested by simulating strong motion records for the loma prieta earthquake m 7 0 using aftershocks m 3 7 to 4 0 recorded at the same sites i use an asperity rupture model where the rms stress drop averaged over the fault plane is constant with moment the observed spectra indicate that stress drop remains constant from the m 3 aftershocks up to the m 7 mainshock about six orders of magnitude in seismic moment each simulation sums the seismogram of one aftershock with time delays appropriate for propagating rupture and incorporates directivity and site response the simulation scales the spectrum in accordance with a constant stress drop 2 source model in this procedure the high frequency energy of the aftershock sum above the corner frequency of the aftershock is not reduced when it is convolved with the mainshock slip velocity function unlike most previous methods of summation for most cases the spectra 0 6 to 20 hz peak accelerations and durations of the simulated mainshock records are in good agreement with the observed strong motion records even though only one aftershock waveform was used in each simulation this agreement indicates that the response of these soil sites is essentially linear for accelerations up to about 0 3 g the summed aftershock records display the same site dependent values of f max as the mainshock records implying that f max is a site effect rather than a property of the mainshock rupture process

sensitivity of net mass balance estimates to near surface temperature lapse rates when employing the degree day method to estimate glacier melt glacier mass balance models that employ the degree day method of melt modeling are most commonly driven by surface air temperatures that have been downscaled over the area of interest using digital elevation models and assuming a constant free air lapse rate that is often taken to be the moist adiabatic lapse rate malr 6 58 ck m 1 air temperature lapse rates measured over melting glacier surface are however consistently less steep than free air values and have been shown to vary systematically with lower tropospheric temperatures in this study the implications of including a variable near surface lapse rate in a 26 year 1980 2006 degree day model simulation of the surface mass balance of devon ice cap nunavut canada are examined and compared with estimates derived from surface air temperatures downscaled using a constant near surface lapse rate equal to the measured summer mean 4 98 ck m 1 and the malr our results show that degree day models are highly sensitive to the choice of lapse rate when compared with 23 years of surface mass balance measurements from the northwest sector of the ice cap model estimates are significantly better when surface air temperatures are downscaled using a modeled daily lapse rate rather than a constant lapse equal to either the summer mean or the malr

spatial and temporal variability of air temperature on a melting glacier atmospheric controls extrapolation methods and their effect on melt modeling juncal norte glacier chile 1 temperature data from three automatic weather stations and twelve temperature loggers are used to investigate the spatiotemporal variability of temperature over a glacier its main atmospheric controls the suitability of extrapolation techniques and their effect on melt modeling we use data collected on juncal norte glacier central chile during one ablation season we examine temporal and spatial variability in lapse rates lrs together with alternative statistical interpolation methods the main control over the glacier thermal regime is the development of a katabatic boundary layer kbl katabatic wind occurs at night and in the morning and is eroded in the afternoon lrs reveal strong diurnal variability with steeper lrs during the day when the katabatic wind weakens and shallower lrs during the night and morning we suggest that temporally variable lrs should be used to account for the observed change they tend to be steeper than equivalent constant lrs and therefore result in a reduction in simulated melt compared to use of constant lrs when extrapolating from lower to higher elevations in addition to the temporal variability the temperature elevation relationship varies also in space differences are evident between local lrs and including such variability in melt modeling affects melt simulations extrapolation methods based on the spatial variability of the observations after removal of the elevation trend such as inverse distance weighting or kriging do not seem necessary for simulations of gridded temperature data over a glacier

model study of the spatial distribution of the energy and mass balance of morteratschgletscher switzerland to investigate the spatial distribution of the energy and mass balance fluxes of a glacier a two dimensional mass balance model was developed and applied to morteratschgletscher switzerland the model is driven by meteorological input from four synoptic weather stations located in the vicinity of morteratschgletscher the model results were compared to observations made on the glacier the calculated mean specific mass balance is 0 47 m w e for 1999 and 0 23 m w e for 2000 net shortwave radiation shows a minimum at around 3350 m a s l due to the effects of shading slope aspect reflection from the slopes and obstruction of the sky ignoring these effects results in a 37 increase in the annual incoming shortwave radiation on the glacier causing 0 34 m w e more ablation a 1 c change in the air temperature results in a shift of 0 67 m w e in the mean specific mass balance while altering the precipitation by 10 causes a change of 0 17 m w e

site effects and peak ground accelerations observed in guadalajara mexico for the 9 october 1995 mw 8 colima jalisco earthquake on 3 june 1932 an m s 8 2 shallow thrust subduction earthquake struck the colima jalisco cj region of mexico at an epicentral distance of 250 km from guadalajara the second largest town in mexico the return period of these cj earthquakes has been estimated from 77 to 126 years which suggests the next is likely to occur between 2009 and 2058 as a step toward estimating the seismic hazard posed by potential m s 8 2 events on guadalajara we present a study consisting of the following 1 the analysis of the strong ground motions recorded at guadalajara on 11 free field accelerographs for the cj 9 october 1995 m w 8 earthquake 2 the analysis of the site effects in guadalajara observed for this earthquake and 3 the estimation of the spatial distribution of peak ground acceleration pga in guadalajara for this event we propose validate and apply a recurrent neural network rnn technique to the recorded pga important site effects were identified using the horizontal to vertical and h hrocksite techniques on guadalajara s sandy soil layers with thicknesses h 20 m to the basaltic rock basement the estimated pgas in guadalajara for the cj 1995 earthquake varied from 2 to 27 cm s2 for soil layers with h 5 m and h 50 m respectively we expect the hybrid technique to obtain broadband synthetics chavez et al 2011 and the proposed rnn methodology can be used to estimate guadalajara s seismic hazard for m w 8 cj scenario earthquakes online material figures of fourier amplitude spectra h v and h h spectral ratios and signal to noise spectral ratios

influence of el nino on the upper ocean circulation in the tropical atlantic ocean abstract this study investigates the influence of el nino on the upper ocean circulation in the tropical atlantic ocean via changes in the atlantic trade winds by analyzing observed sea surface temperature sst together with an ocean general circulation model integration forced by the ncep ncar reanalysis during periods with anomalously warm cold eastern equatorial pacific sst the southern atlantic tropical cell is strengthened weakened the difference of the cell strength between el nino and la nina years is about 20 of the mean cell strength however the variability of the cell is not dominated by the remote forcing from the eastern equatorial pacific but seems to be caused by intrinsic tropical atlantic variability a strengthening weakening for periods with anomalously warm cold eastern equatorial pacific sst is also found for the zonal surface and subsurface currents topex poseidon altimetry data are used to validate the results based on the ogcm integration

tropical atlantic sea surface temperature variability and its relation to el nino southern oscillation past analyses of tropical atlantic sea surface temperature variability have suggested a dipole behavior between the northern and southern tropics across the intertropical convergence zone itcz by analyzing an improved 43 year 1950 1992 record of sst smith et al 1996 and other data derived from the comprehensive ocean atmosphere data set coads it is shown that the regions north and south of the itcz are statistically independent of each other at the seasonal to interannual timescales dominating the data confirming the conclusions of houghton and tourre 1992 some dipole behavior does develop weakly during the boreal spring season when there is a tendency for sst anomaly west of angola to be opposite of that in the tropical north atlantic it is further shown that tropical atlantic sst variability is corre lated with pacific e1 nifio southern oscillation enso variability in several regions the ma jor region affected is the north atlantic area of ne trades west of 40ow along 10on 20on and extending into the caribbean there about 50 80 of the anomalous sst variability is associ ated with the pacific enso with atlantic warmings occurring 4 5 months after the mature phases of pacific warm events an analysis of local surface flux fields derived from coads data shows that the enso related atlantic warmings occur as a result of reductions in the surface ne trade wind speeds which in turn reduce latent and sensible heat losses over the region in ques tion as well as cooling due to entrainment this enso connection is best developed during the boreal spring following the most frequent season of maximum enso anomalies in the pacific a region of secondary covariability with enso occurs along the northern edge of the mean itcz position and appears to be associated with northward migrations of the itcz when the north at lantic warmings occur although easterly winds are intensified in the western equatorial atlantic in response to pacific warm events they do not produce strong local changes in sst contrary to expectations from studies based on equatorial dynamics these teleconnected wind anomalies do not give rise to significant correlations of sst in the gulf of guinea with the pacific enso as the teleconnection sequence matures strong se trades at low southern latitudes follow the de velopment of the north atlantic sst anomaly and precede by several months the appearance of weak negative sst anomalies off angola and stronger positive anomalies extending eastward from southern brazil along 15o 30os

identification of the eurasian north pacific multidecadal oscillation and its relationship to the amo abstracta multidecadal geopotential height pattern in the upper troposphere of the extratropical northern hemisphere nh is identified in this study this pattern is characterized by the nearly zonal symmetry of geopotential height and temperature between 35 and 65 n and the equivalent barotropic vertical structure with the largest amplitude in the upper troposphere this pattern is named the eurasian pacific multidecadal oscillation eapmo to describe its multidecadal time scale and the largest amplitudes over eurasia and the north pacific although nearly extending over the entire extratropics the eapmo exhibits larger amplitudes over western europe east asia and the north pacific with a zonal scale equivalent to zonal wavenumbers 4 and 5 the zonally asymmetric perturbation tends to amplify over the major mountain ranges in the region suggesting a significant topographic influence the eapmo has fluctuated concurrently with the atlantic multidecadal oscillation amo at least since the beginning

melt and surface sublimation across a glacier in a dry environment distributed energy balance modelling of juncal norte glacier chile previous estimates of melt and surface sublimation on glaciers of the subtropical semiarid andes 29 34 s have been obtained at few specific locations but it is not clear how ablation components vary across the entire extent of a glacier in this dry environment here we simulate the distributed energy and mass balance of juncal norte glacier 33 s during a 2 month summer period forcing fields of near surface air temperature and wind speed are generated using two methods accounting for the main physical processes that shape their spatial variations simulated meteorological variables and ablation agree well with observations on the glacier tongue and reveal complex patterns of energy and mass fluxes ablation decreases from 70 mm w e d 1 at the low albedo glacier terminus 3000 m where almost 100 of total ablation corresponds to melt to 75 of total ablation our simulations provide the first glacier scale estimates of ablation components on a glacier in the study region and better reproduce the observed and expected spatial variations of melt and surface sublimation in comparison with more simple assumptions such as linear gradients and uniform wind speeds

hintereisferner austria mass balance reconstruction and numerical modelling of the historical length variations in this study an attempt is made to simulate the historical length variations of hintereisferner austria key elements in the model are 1 reconstruction of the local climate vent 2 multiple linear regression analysis between measured climate and mass balance variations 3 reconstruction of the mass balance with 1 and 2 4 a one dimensional numerical ice flow model forced by the mass balance history

degree day glacier mass balance modelling with applications to glaciers in iceland norway and greenland a degree day glacier mass balance model is applied to three glaciers in iceland norway and greenland for which detailed mass balance measurements are available over a period of several years model results are in good agreement with measured variations in the mass balance with elevation over the time periods considered for each glacier in addition the model explains 60 80 of the year to year variance in the elevation averaged summer season mass balance measurements on the glaciers using a single parameter set for each glacier the increase in ablation on the glaciers due to a warming of 2 c is predicted to range from about 1 m w e year 1 at the highest elevations to about 2 5 m w e year 1 at the lowest elevations predicted changes in the winter balance measured between fixed date are relatively small except at the lowest elevations on the icelandic and norwegian glaciers where the winter balance is significantly reduced equilibrium line altitudes are raised by 200 300 m on the icelandic and norwegian glaciers except at the highest elevations the winter balance of the icelandic and norwegian glaciers is predicted to decrease even if the warming is accompanied by a 10 increase in the precipitation no firm evidence of a climate related variation in the degree day factors or in the temperature lapse rate on the same glacier could be found the model furthermore reproduces large variations in the mass balance with elevation and from year to year on each glacier using the same parameter set we assume therefore that these parameters will not change significantly for the climate scenarios considered here

enhanced relationship between the tropical atlantic sst and the summertime western north pacific subtropical high after the early 1980s the western north pacific subtropical high wnpsh in boreal summer shows a remarkable enhancement after the early 1980s whereas the sea surface temperature sst in the north indian ocean nio and the equatorial eastern pacific had been noted to have remarkable local or remote effects on enhancing the wnpsh the influence of the atlantic sst so far is hardly explored this article reports a new finding enhanced relationship between the tropical atlantic ta sst and the wnpsh after the early 1980s regression study suggests that the warm ta sst produced a zonally overturning circulation anomaly with descending over the equatorial central pacific and ascending over the tropical atlantic eastern pacific the anomalous descending over the equatorial central pacific likely induced low level anticyclonic anomaly to the west and therefore enhanced the wnpsh one implication of this new finding is for predictability the well known spring predictability barrier i e the influence of el nino southern oscillation enso falls dramatically during boreal spring does not apply to the ta sst wnpsh relationship the ta sst shows consistently high correlation starting from boreal spring when the enso influence continues declining the ta sst extends the predictability of the wnpsh in boreal summer approximately one season earlier to boreal spring

conditional probabilities for the recurrence of large and great interplate earthquakes along the mexican subduction zone abstract time dependent conditional probabilities for the recurrence of large and great interplate earthquakes along the mexican subduction zone are presented for time intervals of 5 10 and 20 yr duration i e 1986 1991 1986 1996 and 1986 2006 at present the central oaxaca 97 3 to 97 7 w ometepec san marcos 98 2 to 99 5 w and central guerrero 100 to 101 w segments stand out as having the highest probability for the recurrence of large and great earthquakes in the near future segmentation of the margin is delineated by the rupture zones of the most recent earthquakes occurring in each area for segments of the mexican margin with one or more known recurrence intervals probability estimates are based on the observed average recurrence time for each segment and the lognormal probability distribution function use of a generic distribution function nishenko and buland 1987 allows a more stable estimate of average recurrence times than are available from a few observations a long term prediction time window is also defined based on the 90 per cent confidence interval for our estimates of the recurrence time use of a predetermined confidence interval conveys valuable additional information as to the precision and information content of the forecast for those segments of the margin with only one prior event and hence no historically observed recurrence times repeat times are estimated by extrapolating the observed recurrence time behavior in oaxaca subject to the assumptions that recurrence time scales only as a function of the ratio of seismic displacement and convergence rate and that all events are characterized as simple sources i e involve the rupture of a single asperity

air temperature distribution and energy balance modelling of a debris covered glacier near surface air temperature is an important determinant of the surface energy balance of glaciers and is often represented by a constant linear temperature gradients tgs in models spatiotemporal variability in 2 m air temperature was measured across the debris covered miage glacier italy over an 89 d period during the 2014 ablation season using a network of 19 stations air temperature was found to be strongly dependent upon elevation for most stations even under varying meteorological conditions and at different times of day and its spatial variability was well explained by a locally derived mean linear tg mg tg of 0 0088 c m 1 however local temperature depressions occurred over areas of very thin or patchy debris cover the mg tg together with other air tgs extrapolated from both on and off glacier sites were applied in a distributed energy balance model compared with piecewise air temperature extrapolation from all on glacier stations modelled ablation using the mg tg increased by 4 using the environmental lapse rate ice melt under thick debris was relatively insensitive to air temperature while the effects of different temperature extrapolation methods were strongest at high elevation sites of thin and patchy debris cover

the signature of the annular modes in the tropical troposphere the extratropical annular modes are coupled with a distinct pattern of climate anomalies that spans the circulation of the tropical troposphere the signature of the annular modes in the tropical troposphere exhibits a high degree of equatorial symmetry it is associated with upper tropospheric zonal wind anomalies centered about the equator midtropospheric temperature anomalies located 208n and 208s and opposing mean meridional circulation anomalies that span the subtropics of both hemispheres the linkages between the annular modes and the tropical circulation are only evident during the cold season months and are most robust in association with the northern hemisphere annular mode nam the coupling between the annular modes and the circulation of the tropical troposphere is consistent with forcing by waves originating at extratropical latitudes both annular modes are characterized by anomalies in the eddy momentum flux convergence at tropical latitudes that act to reinforce the changes in the tropical wind and temperature fields the most pronounced tropical anomalies lag indices of the annular modes by 2 weeks and are found over the eastern tropical pacific where climatological westerlies permit extratropical waves to propagate into the deep tropics the linkages between the nam and the tropical tropospheric circulation are

surface mass balance of glaciers in the french alps distributed modeling and sensitivity to climate change a new physically based distributed surface mass balance model is presented for alpine glaciers based on the crocus prognostic snow model it resolves both the temporal 1 hour time step and spatial 200 m grid step variability of the energy and mass balance of glaciers mass balance reconstructions for the period 1981 2004 are produced using meteorological reconstruction from the safran meteorological model for glacier de saint sorlin and glacier d argentiere french alps both glaciers lost mass at an accelerated rate in the last 23 years the spatial distribution of precipitation within the model grid is adjusted using field mass balance measurements this is the only correction made to the safran meteorological input to the glacier model which also includes surface atmospheric temperature moisture wind and all components of downward radiation independent data from satellite imagery and geodetic measurements are used for model validation with this model glacier sensitivity to climate change can be separately evaluated with respect to a full range of meteorological parameters whereas simpler models such as degree day models only account for temperature and precipitation we provide results for both mass balance and equilibrium line altitude ela using a generic alpine glacier the sensitivity of the ela to air temperature alone is found to be 125 m c 1 or 160 m c 1 if concurrent stefan boltzmann longwave radiation change is taken into account

2 m temperatures along melting mid latitude glaciers and implications for the sensitivity of the mass balance to variations in temperature in calculations of the variation in the 2 m temperature along glaciers the lapse rate is generally assumed to be constant this implies that the ratio of changes in the 2 m temperature above a glacier to changes in the temperature outside the thermal regime of that glacier climate sensitivity is equal to 1 however data collected during the ablation season on several mid latitude glaciers show that this sensitivity is smaller than 1 the lowest measured value 0 3 was obtained on the tongue of the pasterze a glacier in austria the measured temperature distribution along the pasterze cannot be described by a constant lapse rate either however there is almost a linear relationship between potential temperature and the distance along die glacier this paper introduces a simple analytical thermodynamic glacier wind model which can be applied to melting glaciers and which explains the observed climate sensitivities and temperature distributions much better than calculations based on a constant lapse rate this way of modelling the 2 m temperatures has implications for the sensitivity of the surface mass balance to atmospheric warming outside the thermal regime of the glacier the magnitude of this sensitivity is computed with a surface energy balance model applied to the pasterze when a constant lapse rate is used instead of the proposed glacier wind model to compute changes in the 2 m temperature along the glacier the negative change in mass balance due to 1 c warming is overestimated by 22

teleseismic body wave analysis of the 9 october 1995 mw 8 0 colima jalisco mexico earthquake and its largest foreshock and aftershock the source process of the october 9 1995 colima jalisco mexico earthquake mw 8 0 and its largest foreshock and aftershock were determined from teleseismic body waves using a least squares inversion scheme the three events are shallow dipping thrust fault earthquakes in agreement with the relative plate motions for rivera north america and cocos north america plate boundaries neither the foreshock nor the largest aftershock show significant differences in focal mechanism nor centroidal depth with respect to the average mechanism of the mainshock the rupture of the mainshock began near the foreshock hypocenter and propagated with a variable rupture velocity towards the nw the source time function for this event shows four distinct episodes of energy release about 50 of the moment was released at the northern end of the rupture between 90 and 110 km from the epicenter this rupture geometry is in agreement with crustal deformation observed inland using gps measurements however the scalar seismic moment of the main shock obtained in this study mo 1 84 1020 is smaller with respect to the lower frequency cmt results reported by harvard mo 1 15 1021

baffin island snow extent sensitivity insights from a regional climate model 1 recent modeling efforts suggest that the little ice age lia onset could be explained by a series of four large decadally spaced volcanic eruptions at that time glaciers on baffin island advanced and did not retreat until the past century perhaps due to arctic and north atlantic ocean sea ice feedbacks to try to determine what parameters sustain snow cover we investigate the relative impacts of changes in radiation and advection on minimum summer snow extent over baffin island we used the weather research and forecasting wrf model to run eight 6 month long april september 10 km resolution simulations in which we varied boundary condition temperatures solar radiation and sea ice cover although the control run underestimated cloud cover and thus produced an exaggerated diurnal 2 m temperature cycle the relative changes of snow extent show that wrf accurately simulates snow expansion into the same regions as during the lia with an average temperature decrease from current temperatures by 3 9 1 1 k it only requires one season for the model to lower the snowline by comparable elevation changes seen during the descent into the lia wrf s maximum snow line sensitivity is 7 k km within the range of the typically assumed lapse rate of 5 7 k km in the canadian arctic thus if a shift in the arctic climate greatly expanded sea ice coverage following large volcanic eruptions this would have been enough to perpetuate an ice sheet on baffin island throughout the lia

spring arctic oscillation east asian summer monsoon connection through circulation changes over the western north pacific in the present study the links between spring arctic oscillation ao and east asian summer monsoon easm was investigated with focus on the importance of the north pacific atmospheric circulation and sea surface temperature sst to reduce the statistical uncertainty we analyzed high pass filtered data with the inter annual time scales and excluded the el nino southern oscillation signals in the climate fields using a linear fitting method the significant relationship between spring ao and easm are supported by the changes of multi monsoon components including monsoon indices precipitation and three dimensional atmospheric circulations following a stronger positive spring ao an anomalous cyclonic circulation at 850 hpa appears in southeastern asia and the western north pacific in summer with the easterly anomalies spanning from the pacific to asian continent along 25 n 30 n and the westerly anomalies south of 15 n at the same time the summer western north pacific subtropical high becomes weaker consistently the positive precipitation anomalies are developed over a broad region south of 30 n stretching from southern china to the western pacific and the negative precipitation anomalies appear in the lower valley of the yangtze river and southern japan the anomalous cyclone in the western north pacific persisting from spring to summer plays a key role in modulating easm and monsoon precipitation by a positive air sea feedback mechanism during spring the ao associated atmospheric circulation change produces warmer ssts between 150 e 180 near the equator the anomalous sensible and latent heating in turn intensifies the cyclone through a gill type response of the atmosphere through this positive feedback the tropical atmosphere and sst patterns sustain their strength from spring to summer that consequently modifies the monsoon trough and the western north pacific subtropical high and eventually the easm precipitation moreover the sst response to ao circulation is supported by the numerical simulations of an ocean model and the anomalous atmospheric circulation over the western north pacific is also reproduced by the dedicated numerical simulations using the coupled atmosphere ocean model the observation evidence and numerical simulations suggest the spring ao can impact the easm via triggering tropical air sea feedback over the western north pacific

centreline and cross glacier air temperature variability on an alpine glacier assessing temperature distribution methods and their influence on melt model calculations the spatio temporal distribution of air temperature over mountain glaciers can demonstrate complex patterns yet it is often represented simplistically using linear vertical temperature gradients vtgs extrapolated from off glacier locations we analyse a network of centreline and lateral air temperature observations at tsanteleina glacier italy during summer 2015 on average vtgs are steep 1 but they are shallow under warm ambient conditions when the correlation between air temperature and elevation becomes weaker published along flowline temperature distribution methods explain centreline observations well including warming on the lower glacier tongue but cannot estimate lateral temperature variability application of temperature distribution methods improves simulation of melt rates rmse in an energy balance model by up to 36 compared to the environmental lapse rate extrapolated from an off glacier station however results suggest that model parameters are not easily transferable to glaciers with a small fetch without recalibration such methods have potential to improve estimates of temperature across a glacier but their parameter transferability should be further linked to the glacier and atmospheric characteristics furthermore cold spots which can be 2 c cooler than expected for their elevation whose occurrence is not predicted by the temperature distribution models are identified at one quarter of the measurement sites

climate variability and glacier reaction in the austrian eastern alps a carefully homogenized climate dataset is used to interpret glacier behaviour in the austrian alps periods of glacier advance are generally more maritime and cooler with reduced sunshine duration and increased precipitation sum during the ablation period periods of retreat are associated with a more continental warmer climate with increased sunshine duration and reduced precipitation sum three recent sub periods of austrian glacier behaviour are documented by direct measurement of glacier mass balance before 1965 more negative 1965 81 more positive since 1982 more negative a long term mass balance series in the eastern part of the austrian alps parameterized by snow depth measurements indicates very clearly that periods of more negative mass balance have a higher correlation to summer air temperature and a lower correlation to winter accumulation periods of more positive mass balance are highly correlated to winter accumulation and only slightly correlated to summer temperature the positive mass balance period 1965 81 is also characterized by negative north atlantic oscillation index values which caused an increased meridional circulation mode resulting in a northwesterly to northerly precipitation regime during winter

comparison of the meteorology and surface energy fluxes of debris free and debris covered glaciers in the southeastern tibetan plateau knowledge of debris free and debris covered glaciers is important for understanding the varying response of glaciers to climate change measurements at the debris free parlung no 4 glacier and the debris covered 24 k glacier in the southeastern tibetan plateau were carried out to compare the meteorology and surface energy fluxes and to understand the factors controlling the melting process the meteorological comparisons displayed temporally synchronous fluctuations in air temperature relative humidity and incoming longwave radiation l in but notable differences in precipitation incoming shortwave radiation s in and wind speed under the prevailing regional precipitation and debris conditions more l in 42 w m 2 was supplied from warmer and more humid air and more s in 58 w m 2 was absorbed at the 24 k glacier the relatively high energy supply led mainly to an increased energy output via turbulent heat fluxes and outgoing longwave radiation rather than glacier melting beneath the thick debris the sensitivity experiment showed that melt rates were sensitive to energy supply at debris thicknesses similar to 10 cm in contrast energy supply to the parlung no 4 glacier mainly resulted in snow ice melting the magnitude of which was significantly influenced by energy supplied by s in and the sensible heat flux

modeling 2 m air temperatures over mountain glaciers exploring the influence of katabatic cooling and external warming air temperature is one of the most relevant input variables for snow and ice melt calculations however local meteorological conditions complex topography and logistical concerns in glacierized regions make the measuring and modeling of air temperature a difficult task in this study we investigate the spatial distribution of 2 m air temperature over mountain glaciers and propose a modification to an existing model to improve its representation spatially distributed meteorological data from haut glacier d arolla switzerland place canada and juncal norte chile glaciers are used to examine approximate flow line temperatures during their respective ablation seasons during warm conditions off glacier temperatures well above 0 c observed air temperatures in the upper reaches of place glacier and haut glacier d arolla decrease down glacier along the approximate flow line at juncal norte and haut glacier d arolla an increase in air temperature is observed over the glacier tongue while the temperature behavior over the upper part can be explained by the cooling effect of the glacier surface the temperature increase over the glacier tongue may be caused by several processes induced by the surrounding warm atmosphere in order to capture the latter effect we add an additional term to the greuell and bohm gb thermodynamic glacier wind model for high off glacier temperatures the modified gb model reduces root mean square error up to 32 and provides a new approach for distributing air temperature over mountain glaciers as a function of off glacier temperatures and approximate glacier flow lines

enhanced influences of tropical atlantic sst on wnp nio atmosphere ocean coupling since the early 1980s abstractthis paper reports a new finding and related mechanism the forcing effect of the tropical atlantic ta sea surface temperature sst on the atmosphere ocean coupling in the western north pacific wnp and northern indian ocean nio since the early 1980s the ta sst has increased and notably exhibited an enhanced interannual statistical relationship with the wnp subtropical high and nio sst in boreal summer empirical diagnostics reveal the following spatial pattern linking the ta sst and the atmosphere ocean coupling in the pacific and indian ocean 1 a cyclonic anticyclonic circulation pair straddling the equator over the eastern pacific 2 an anticyclonic cyclonic circulation pair straddling the equator in the wnp and indian ocean 3 overturning circulation with ascending descending and descending ascending anomalies over the ta and tropical western pacific respectively and 4 positive negative sst anomaly in the ta and nio the characteristics of this pattern are consistent

remote forcing of the northern tropical atlantic sst anomalies on the western north pacific anomalous anticyclone this study uses both observations and numerical modeling experiments to investigate the lead lag relationship and the associated physical mechanism of the western north pacific anomalous anticyclone wnpac with sea surface temperature sst anomalies over the northern tropical atlantic nta the results show that the wnpac from late spring to the middle of autumn has a significant in phase relationship with the nta sst anomalies up to two seasons ahead this relationship reaches a peak when the nta sst leads by approximately 1 2 months and is nearly independent of the el nino southern oscillation variability diagnosis based on observations and numerical experiments using the community atmospheric model version 5 3 reveals that the nta warming favors intensified local convection activity during the spring autumn seasons causing enhanced low level convergence and upper level divergence i e ascending motion over the nta and opposite flow anomalies over the central tropical pacific the enhanced subsidence over the central tropical pacific in turn triggers an anomalous low level anticyclone over the western north pacific moreover the intensity of the anomalous local convection activity that is associated with the nta sst is closely related to the seasonal migration of the atlantic intertropical convergence zone itcz as the atlantic itcz migrates northward the nta sst induced local convection activity extends northward from a narrow band near the equator during early spring to nearly the entire nta region during the middle of summer leading to the strongest remote effect of the nta sst anomalies on the wnpac during late summer and early autumn

pakistan s two stage monsoon and links with the recent climate change 1 meteorological conditions related to the pakistan floods of 2010 were examined in the context of monsoon dynamics and large scale circulations case and climatological analyses suggest that summer precipitation in northern pakistan comprises two distinct phases 1 a premonsoon trough phase july whose rainfall is more episodic and intense occurring prior to arrival of the monsoon trough and 2 a monsoon trough phase august whose rainfall is persistent yet less episodic driven by northward migration of the monsoon trough analyses of conditional instability moisture flux and circulation features support a persistent increase in conditional instability during the july premonsoon trough phase accompanied by increased frequency of heavy rainfall events conversely evidence does not support intensification of the august monsoon trough phase the increased convective activity during the premonsoon trough phase agrees with the projected increase in the intensity of heavy rainfall events over northern pakistan large scale circulation analysis reveals an upper level cyclonic anomaly over and to the west of pakistan a feature empirically associated with weak monsoon the analysis also suggests that the anomalous circulation in 2010 is not sporadic but rather is part of a long term trend that defies the typical linkage of strong monsoons with an anomalous anticyclone in the upper troposphere

mass balance gradients and climatic change it is generally assumed that the mass balance gradient on glaciers is more or less conserved under climatic change in studies of the dynamic response of glaciers to climatic change one of the following assumptions is normally made i the mass balance perturbation is independent of altitude or ii the mass balance profile does not change it simply shifts up and down observational evidence for such an approach is not convincing on some glaciers the inter annual changes in mass balance seem to be independent of altitude on others not at all moreover it is questionable whether inter annual variation can be projected on different climatic states to see what a physical approach might contribute we developed an altitude dependent mass balance model it is based on the energy balance of the ice snow surface where precipitation is included in a parameterized form and numerical integrations are done through an entire balance year with a 30 min time step atmospheric temperature snowfall and atmospheric transmissivity for solar radiation are all dependent on altitude so a mass balance profile can be calculated slope and exposure of the ice snow surface are taken into account and the effects of these parameters studied in general the calculations were done for 100 m elevation intervals climatological data from the sonnblick observatory austria 3106 m a s l and from vent 2000 m a s l oetztal alps austria served as input for a number of runs simulation of the mass balance profiles for hinterseisferner north easterly exposure and kesselwandferner southeasterly exposure yields reasonable results the larger balance gradient on kesselwandferner is produced by the model so exposure appears to be an important factor here sensitivity of mass balance profiles to shading effects different slope and exposure are systematically studied another section deals with the sensitivity to climatic change perturbations of air temperature cloudiness albedo and precipitation are imposed to see their effects on the mass balance profiles the results clearly show that in general mass balance perturbations depend strongly on altitude they generally increase down glacier and are not always symmetric about the reference state for typical climatic conditions in the alps we found that a 1 k temperature change leads to a change in equilibrium line altitude of 130 m three factors contribute to this large value turbulent heat flux longwave radiation from the atmosphere and fraction of precipitation falling as snow here the albedo feed back increases the sensitivity in a significant way

interannual relationships between the tropical sea surface temperature and summertime subtropical anticyclone over the western north pacific 1 the interannual variability of the western north pacific subtropical high wnpsh in boreal summer is investigated with the use of the ncep ncar reanalysis data the most significant change of the 500 hpa geopotential height field appears at the western edge of the wnpsh with dominant 2 3 year and 3 5 year power spectrum peaks the 2 3 year oscillation of the wnpsh and associated circulation and sea surface temperature sst patterns possess a coherent eastward propagating feature with a warm sst anomaly ssta and anomalous ascending motion migrating from the tropical indian ocean in the preceding autumn to the maritime continent in the concurrent summer of a strong wnpsh a strong wnpsh is characterized by anomalous anticyclonic circulation and maximum subsidence in the western north pacific wnp the anomalous wnpsh circulation has an equivalent barotropic vertical structure and resides in the sinking branch of the local hadley circulation triggered by enhanced convection over the maritime continent a heat budget analysis reveals that the wnpsh is maintained by radiative cooling the 3 5 year oscillation of the wnpsh exhibits a quasi stationary feature with a warm ssta anomalous ascending motion located in the equatorial central eastern pacific and indian ocean and a cold ssta anomalous descending motion located in the western pacific the anomaly pattern persists from the preceding winter to the concurrent summer of a high wnpsh the greatest descent is located to the southeast of the anomalous anticyclone center where a baroclinic vertical structure is identified the zonal phase difference and the baroclinic vertical structure suggest that the anomalous anticyclone on this timescale is a rossby wave response to a negative latent heating associated with the persistent local cold ssta echam4 model experiments further confirm that the 2 3 year mode is driven by the ssta forcing over the maritime continent while the 3 5 year mode is driven by the local ssta in the wnp

derivation of melt factors from glacier mass balance records in western canada melt factors for snow k s and ice k i were derived from specific mass balance data and regionally interpolated daily air temperature series at nine glaciers in the western cordillera of canada fitted k s and k i were relatively consistent across the region with mean values standard deviations of 3 04 0 38 and 4 59 0 59 mm d 1 c 1 respectively the interannual variability of melt factors was investigated for two long term datasets calculated annually snow and ice melt factors were relatively stable from year to year standard deviations for snowmelt factors were 0 48 17 and 0 42 18 at peyto and place glaciers respectively while standard deviations of ice melt factors were 1 17 25 and 0 81 14 while fitted values of k s are comparable to those presented in previous observational and modeling studies fitted k i are substantially and consistently lower across the region fitted melt factors were sensitive to the choice of lapse rate used in the air temperature interpolation melt factors fitted to mass balance data from a single site place glacier provided reasonable summer balance predictions at most other sites representing both maritime and continental climates although there was a tendency for under prediction at several sites the combination of regionally interpolated air temperatures and a degree day model appears capable of generating first order estimates of regional summer balance which can provide a benchmark against which to judge the predictive ability of more complex e g energy balance models applied at a regional scale mass balance sensitivity analyses indicate that a temperature increase of 1 k will increase summer ablation in the region by 0 51 m w e a 1 on average

source characteristics of hypothetical subduction earthquakes in the northwestern united states historic earthquake sequences on subduction zones that are similar to the cascadia subduction zone are used to hypothesize the nature of shallow subduction earthquakes that might occur in the northwestern united states based on systematic comparisons of several physical characteristics including physiography and seismicity subduction zones that are deemed most similar to the cascadia subduction zone are those in southern chile southwestern japan and colombia these zones have all experienced very large earthquake sequences and if the cascadia subduction zone is also capable of storing elastic strain energy along its greater than 1000 km length then earthquakes of very large size m w 8 1 2 must be considered circumstantial evidence is presented that suggests but does not prove that large subduction earthquakes along the cascadia subduction zone may have an average repeat time of 400 to 500 yr

variability of air temperature over a debris covered glacier in the nepalese himalaya estimates of melt from debris covered glaciers require distributed estimates of meteorological variables and air temperature in particular meteorological data are scarce for this environment and spatial variability of temperature over debris is poorly understood based on multiple measurements of air and surface temperature from three ablation seasons 2012 14 we investigate the variability of temperature over lirung glacier nepal in order to reveal how air temperature is affected by the debris cover and improve ways to extrapolate it we investigate how much on glacier temperature deviates from that predicted from a valley lapse rate lr analyse on glacier lrs and test regression models of air temperature and surface temperature air temperature over the debris covered glacier tongue is much higher than what a valley lr would prescribe so an extrapolation from off glacier stations is not applicable an on glacier lr is clearly defined at night with strong correlation but not during the day when the warming debris disrupts the elevation control an alternative to derive daytime air temperature is to use a relationship between air and surface temperature as previously suggested we find strong variability during daytime that should be accounted for if these regressions are used for temperature extrapolation

air temperature variability in a high elevation himalayan catchment air temperature is a key control of processes affecting snow and glaciers in high elevation catchments including melt snowfall and sublimation it is therefore a key input variable to models of land surface atmosphere interaction despite this importance its spatial variability is poorly understood and simple assumptions are made to extrapolate it from point observations to the catchment scale we use a dataset of 2 75 years of air temperature measurements from may 2012 to november 2014 at a network of up to 27 locations in the langtang river nepal catchment to investigate air temperature seasonality and consistency between years we use observations from high elevations and from the easternmost section of the basin to corroborate previous findings of shallow lapse rates seasonal variability is strong with shallowest lapse rates during the monsoon season diurnal variability is also strong and should be taken into account since processes such as melt have a pronounced diurnal variability use of seasonal lapse rates seems crucial for glacio hydrological modelling but seasonal lapse rates seem stable over the 2 3 years investigated lateral variability at transects across valley is high and dominated by aspect with south facing sites being warmer than north facing sites and deviations from the fitted lapse rates of up to several degrees local factors e g topographic shading can reduce or enhance this effect the interplay of radiation aspect and elevation should be further investigated with high elevation transects

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