ground based thermal imagery as a simple practical tool for mapping saturated area connectivity and dynamics the hillslope riparian stream system is a key functional unit of catchments yet very difficult to measure and monitor due to its tremendous complexity and high spatio temporal variability here we present a simple and practical tool for imaging directly these hillslope riparian area connections we used a flir b50 infrared camera to produce thermal images at the scale of 140 140 pixels over the spectral range 7 5 13 m our ir imaging technique is sensitive to the upper 0 1 mm of the water column images were obtained from a constant position on the right bank of the weierbach catchment in luxembourg at an incidence angle of approximately 45 over a 5 week period the study site measured 5 3m our results show that ground based ir imagery can discriminate between areas with snow cover snow melt soil seepage and stream water more importantly it can detect when and where variably saturated areas are active and when connectivity exists between the hillslope riparian stream system our proof of concept suggests that this is a simple inexpensive technology for sequential mapping and characterisation of surface saturated areas and a useful complement to conventional tracer techniques copyright 2010 john wiley sons ltd

topographic controls on the surface energy balance of a high arctic valley glacier 1 this paper presents the results of a distributed two dimensional surface energy balance model used to investigate the spatial and temporal variations in the surface energy balance of midre lovenbreen a small valley glacier in northwest spitsbergen svalbard over the summer of 2000 we utilize high resolution airborne lidar data to derive a digital elevation model of the glacier and surrounding topography on which a surface energy balance is computed driven by meteorological data obtained from a meteorological station located on the glacier and a synoptic station maintained at the nearby ny alesund research base given the high resolution topographic data we focus particularly on whether the long duration of sunshine at high latitudes compensates for the higher solar zenith angles on the season long energy balance and whether shading by the surrounding topography plus glacier surface slope and aspect play an increased role in the patterns of solar radiation receipt and hence melt over the glacier surface the model results are validated using a combination of mass balance data from the glacier measured surface lowering at the glacier meteorological station and by comparing a derived energy balance component from the model with a measured energy flux overall the model performance is very good glacier topography is found to play a fundamental role in determining the surface energy balance topographic shading slope and aspect and correction of the surface albedo for high solar zenith angles are found to play a crucial role in determining spatial patterns of surface energy balance and therefore melt

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

evolution of cryoconite holes and their contribution to meltwater runoff from glaciers in the mcmurdo dry valleys antarctica cryoconite holes are water filled holes in the surface of a glacier caused by enhanced ice melt around trapped sediment measurements on the ablation zones of four glaciers intaylorvalley antarctica show that cryoconite holes cover about 4 6 of the ice surface they typically vary in diameter from 5 to 145 cm with depths ranging from 4 to 56 cm in some cases huge holes form with 5 m depths and 30 m diameters un like cryoconite holes elsewhere these have ice lids up to 36 cm thick and melt from within each spring about one half of the holes are connected to the near surface hydrologic system and the remainder are isolated the duration of isolation estimated from the chlor ide accumulation in hole waters commonly shows ages of several years with one hole of 10 years the cryoconite holes in the mcmurdo dryvalleys create a near surface hydro logic system tens of cm below the ice surface the glacier surface itself is generally frozen and dry comparison of water levels between holes a few meters apart shows independent cycles of water storage and release most likely local freeze thaw effects control water passage and therefore temporary storage rough calculations indicate that the holes gen erate at least 13 of the observed runoff on the one glacier measured this hydrologic system represents the transition between a melting ice cover with supraglacial streams and one entirely frozen and absent of water abstract cryoconite holes are water filled holes in the surface of a glacier caused by enhanced ice melt around trapped sediment measurements on the ablation zones of four glaciers intaylorvalley antarctica show that cryoconite holes cover about 4 6 of the ice surface they typically vary in diameter from 5 to 145 cm with depths ranging from 4 to 56 cm in some cases huge holes form with 5 m depths and 30 m diameters un like cryoconite holes elsewhere these have ice lids up to 36 cm thick and melt from within each spring about one half of the holes are connected to the near surface hydrologic system and the remainder are isolated the duration of isolation estimated from the chlor ide accumulation in hole waters commonly shows ages of several years with one hole of 10 years the cryoconite holes in the mcmurdo dryvalleys create a near surface hydro logic system tens of cm below the ice surface the glacier surface itself is generally frozen and dry comparison of water levels between holes a few meters apart shows independent cycles of water storage and release most likely local freeze thaw effects control water passage and therefore temporary storage rough calculations indicate that the holes gen erate at least 13 of the observed runoff on the one glacier measured this hydrologic system represents the transition between a melting ice cover with supraglacial streams and one entirely frozen and absent of water

a further study of the tropical western hemisphere warm pool abstract variability of the tropical western hemisphere warm pool whwp of water warmer than 28 5 c which extends seasonally over parts of the eastern north pacific the gulf of mexico the caribbean and the western tropical north atlantic tna was previously studied by wang and enfield using the da silva data from 1945 93 using additional datasets of the ncep ncar reanalysis field and the ncep sst from 1950 99 and the levitus climatological subsurface temperature the present paper confirms and extends the previous study of wang and enfield the whwp alternates with northern south america as the seasonal heating source for the walker and hadley circulations in the western hemisphere during the boreal winter a strong hadley cell emanates northward from the amazon heat source with subsidence over the subtropical north atlantic north of 20 n sustaining a strong north atlantic anticyclone and associated northeast ne trade winds over its southern limb in the tna this circulation including the ne

six decades of glacier mass balance observations a review of the worldwide monitoring network glacier mass balance is the direct and undelayed response to atmospheric conditions and hence is among the essential variables required for climate system monitoring it has been recognized as the largest non steric contributor to the present rise in sea level six decades of annual mass balance data have been compiled and made easily available by the world glacier monitoring service and its predecessor organizations in total there have been 3480 annual mass balance measurements reported from 228 glaciers around the globe however the present dataset is strongly biased towards the northern hemisphere and europe and there are only 30 reference glaciers that have uninterrupted series going back to 1976 the available data from the six decades indicate a strong ice loss as early as the 1940s and 1950s followed by a moderate mass loss until the end of the 1970s and a subsequent acceleration that has lasted until now culminating in a mean overall ice loss of over 20 m w e for the period 1946 2006 in view of the discrepancy between the relevance of glacier mass balance data and the shortcomings of the available dataset it is strongly recommended to 1 continue the long term measurements 2 resume interrupted long term data series 3 replace vanishing glaciers by early starting replacement observations 4 extend the monitoring network to strategically important regions 5 validate calibrate and accordingly flag field measurements with geodetic methods and 6 make systematic use of remote sensing and geo informatics for assessment of the representativeness of the available data series for their entire mountain range and for the extrapolation to regions without in situ observations and 7 make all these data and related meta information available

decadal climate variability in the eastern caribbean 1 rainfall variability in the eastern caribbean during the 20th century is analyzed using principal component analysis and singular value decomposition in contrast to earlier studies that used seasonal data here we employ continuous signal processing the leading mode is a decadal oscillation related to third and fourth modes of sea level pressure slp and sea surface temperatures sst which together identify three zones of action in the atlantic 35 n 20 n 20 n 5 n and 5 n 20 s the ability of the echam4 5 model to simulate this signal is investigated its decadal variability is also represented through lower order slp and sst modes that comprise an atlantic tripole pattern with lower pressure east of the caribbean composite analysis of high and low phases of the decadal mode reflects a cool east pacific and a more active atlantic intertropical convergence zone during boreal summer conditions that favor the intensification of african easterly waves the decadal signal has strengthened since 1970 yet the three centers of action in atlantic sst are relatively unsynchronized

glacier recession and water resources in peru s cordillera blanca the tropical glaciers of the cordillera blanca peru are rapidly retreating resulting in complex impacts on the hydrology of the upper rio santa watershed the effect of this retreat on water resources is evaluated by analyzing historical and recent time series of daily discharge at nine measurement points using the mann kendall nonparametric statistical test the significance of trends in three hydrograph parameters was studied results are interpreted using synthetic time series generated from a hydrologic model that calculates hydrographs based on glacier retreat sequences the results suggest that seven of the nine study watersheds have probably crossed a critical transition point and now exhibit decreasing dry season discharge our results suggest also that once the glaciers completely melt annual discharge will be lower than present by 2 30 depending on the watershed the retreat influence on discharge will be more pronounced during the dry season than at other periods of the year at la balsa which measures discharge from the upper rio santa the glacier retreat could lead to a decrease in dry season average discharge of 30

annual cycle of subsurface thermal structure in the tropical atlantic ocean abstract the subsurface thermal structure in the tropical atlantic ocean 30 n 20 s east of 80 w is studied on the basis of an extensive data bank of subsurface soundings calendar monthly maps are presented showing mixed layer depth base of thermocline thermocline thickness and vertical temperature gradient across the thermocline these maps are complemented by vertical cross sections depicting mixed layer depth base of thermocline and selected isotherms a zonal profile along the equator 50 w 10 e a meridional transect across the eastern atlantic 4 n 18 s and a meridional section across the central atlantic 30 n 18 s the basinwide subsurface thermal structure is dominated by the annual cycle of the surface wind field with extrema around april and august the mixed layer is relatively shallow between 20 n and 10 s with overall grater depth in the western as compared to the eastern portion of the basin two systems of annual cycle variation of mixed layer depth stand out i along the eq

drought in the northern bahamas from 3300 to 2500 years ago abstract intensification and western displacement of the north atlantic subtropical high nash is projected for this century which can decrease caribbean and southeastern american rainfall on seasonal and annual timescales however additional hydroclimate records are needed from the northern caribbean to understand the long term behavior of the nash and better forecast its future behavior here we present a multi proxy sinkhole lake reconstruction from a carbonate island that is proximal to the nash abaco island the bahamas the reconstruction indicates the northern bahamas experienced a drought from 3300 to 2500 cal yrs bp which coincides with evidence from other hydroclimate and oceanographic records e g africa caribbean and south america for a synchronous southern displacement of the intertropical convergence zone and north atlantic hadley cell the specific cause of the hydroclimate change in the northeastern caribbean region from 3300 to 2500 cal yrs bp was probably coeval southern or western displacement of the nash which would have increased northeastern caribbean exposure to subsiding air from higher altitudes

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

internal accumulation on storglaciaren sweden in a multi layer snow model coupled to a distributed energy and mass balance model to investigate the internal accumulation on storglaciaren sweden we couple a multilayer snow model to a distributed energy and mass balance model the snow model describes the temperature density and water content evolution of the snow ice pack and includes the processes of percolation and refreezing of water the model is run for the period 9 may 2 september 1999 and validated against weather station and mass balance observations on the glacier the model performs reasonably well with an average summer mass balance for the location of stake observations of 1 56 m w e compared to 1 59 m w e observed however the amount of melt is overestimated in the higher parts of the accumulation area and underestimated in the lower parts of the ablation area the modelled mass balance is most sensitive to the albedo parameterization the chosen momentum and scalar roughness lengths and all parameters related to snowfall the modelled internal accumulation is 0 25 m w e which amounts to about 20 of the winter accumulation and results in a positive net balance for 1999 of 0 23 m w e the modelled internal accumulation is most sensitive to the initial subsurface temperature profile and the irreducible water content

fault damage zones of the m7 1 darfield and m6 3 christchurch earthquakes characterized by fault zone trapped waves abstract to characterize the subsurface structure of the damage zones caused by the 2010 2011 canterbury earthquake sequence in new zealand s south island we installed two short linear seismic arrays array 1 across the greendale fault gf surface rupture and array 2 over the surface projection of the blind port hills fault phf that ruptured in the 2010 m7 1 darfield and 2011 m6 3 christchurch earthquakes respectively we recorded 853 aftershocks for 4 months after the christchurch earthquake fault zone trapped waves fztws identified at array 1 for aftershocks occurring on both the gf and the phf show that the post s durations of these fztws increase as focal depths and epicentral distances from the array increase suggesting an effective low velocity waveguide formed by severely damaged rocks existing along the gf and phf at seismogenic depths locations of aftershocks generating prominent fztws delineates the subsurface gf rupture extending eastward as bifurcating blind fault segments an additional 5 8 km beyond the mapped 30 km surface rupture into a zone with comparably lower seismic moment release west of the phf rupture which extends westward to within 5 3 1 km of the subsurface gf the propagation of fztw through the intervening gap indicates moderate gf phf structural connectivity we interpret this zone as a fracture mesh reflecting the interplay between basement faults and stress aligned microcracks that enable the propagation of phf sourced fztws into the gf damage zone simulations of observed fztws suggest that the gf rupture zone is 200 250 m wide consistent with the surface deformation width velocities within the zone are reduced by 35 55 with the maximum reduction in the 100 m wide damage core zone corresponding with surface and shallow subsurface evidence for discrete fracturing the damage zone extends down to depths of 8 km or deeper consistent with hypocentral locations and geodetically derived fault models

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

strain accumulation in southern california 1973 1980 frequent surveys of seven trilateration networks in southern california over the interval 1973 1980 suggest that a regional increment in strain may have occurred in 1978 1979 prior to 1978 and after late 1979 the strain accumulation has been predominantly a uniaxial north south compression this secular trend was interrupted sometime in 1978 1979 by an increment in both north south and east west extension in five of the seven networks the onset of this change appears to have occurred first in the networks farthest south the changes occurred without any unusual seismicity within the networks but the overall seismicity in southern california was unusually low prior to and has been unusually high since the occurrence the average principal strain rates for the seven networks in the 1973 1980 interval are 0 17 mu strain yr north south contraction and 0 08 mu strain yr east west extension although the observed increment in strain could be related to unidentifed systematic error in the measuring system a careful review of the measurements and comparison with three other measuring systems reveal no appreciable cumulative systematic error

classification seasonality and persistence of low frequency atmospheric circulation patterns abstract orthogonally rotated principle component analysis rpca of northern hemisphere 1 month mean 700 mb heights is used to identify and describe the seasonality and persistence of the major modes of interannual variability the analysis is detailed and comprehensive in that 1 a high resolution approximately equal area 358 point grid is used for the virtually maximum possible 35 year period of record 2 a positive bias in the nmc data base in the early 1950s in the subtropics is largely eliminated for the first time and 3 homogeneous separate analyses of each month of the year are carried out detailing the mouth to month changes in the dominant circulation patterns winter results are similar to those of other recent rpca and teleconnection studies except that some less obvious patterns are identified and further detail of the better known patterns is provided two north south dipole patterns are found over the pacific ocean west pacific oscillation and east pacific pattern and over the atla

robustness of low frequency circulation patterns derived from eof and rotated eof analyses abstract the robustness of low frequency circulation patterns defined by unrotated and rotated empirical orthogonal functions e0fs are compared based on the northern hemisphere 10 day low pass filtered wintertime 500 hpa height field the pacific north american pattern and the north atlantic oscillation are the most prominent modes of low frequency variability in the data the reproducibility of the spatial patterns derived from eof and rotated eof analysis is assessed by repeating the analysis on 50 subsets of the data each comprised of the maps belonging to 22 randomly selected winters from the 44 winters in the total record the results indicate that rotated spatial patterns are less sensitive to sampling fluctuations than their unrotated counterparts

stress field in friuli ne italy from fault plane solutions of activity following the 1976 main shock abstract fault plane solutions of 78 earthquakes with magnitude larger than 3 2 which occurred in friuli between may 1976 and august 1979 have been used to estimate the orientations of the principal stress axes by an inversion technique the analysis of the confidence limits and the average angular misfit of the solution found when inverting the entire data set revealed that faulting was not produced by a uniform stress distribution subdivision of the study area into smaller volumes did not lead to significant improvements in terms of stress uniformity whereas temporal subdivision of the sample reduced significantly misfit and confidence areas of the solution for some data sets therefore we conclude that the stress directions changed as a function of time a nearly uniform stress direction compatible with tectonic models proposed for the study area ca n s convergence of the adriatic and south alpine units was found between the main event of 6 may 1976 m l 6 4 and the strong aftershocks of mid september 1976 5 1 m l 6 1 the analysis of the individual misfit cumulative pattern reveals that some degree of stress heterogeneity appeared in july 1976 which is explained here in terms of heterogeneous local responses of the stress field to the seismic activity superimposed to the regional compressive factor the degree of perturbation of the principal stress directions by local effects increased with time and showed in particular a clear variation after the strong earthquakes of mid september 1976 the perturbations appear to be reflected by low magnitude quakes whereas the faulting in strong events is compatible with the regional stress field

mid to late holocene changes in tropical atlantic temperature seasonality and interannual to multidecadal variability documented in southern caribbean corals proxy reconstructions of tropical atlantic sea surface temperature sst that extend beyond the period of instrumental observations have primarily focused on centennial to millennial variability rather than on seasonal to multidecadal variability here we present monthly resolved records of sr ca a proxy of sst from fossil annually banded diploria strigosa corals from bonaire southern caribbean sea the individual corals provide time windows of up to 68 years length and the total number of 295 years of record allows for assessing the natural range of seasonal to multidecadal sst variability in the western tropical atlantic during snapshots of the mid to late holocene comparable to modern climate the coral sr ca records reveal that mid to late holocene sst was characterised by clear seasonal cycles persistent quasi biennial and prominent interannual as well as inter to multidecadal scale variability however the magnitude of sst variations on these timescales has varied over the last 6 2 ka the coral records show increased seasonality during the mid holocene consistent with climatemodel simulations indicating that southern caribbean sst seasonality is induced by insolation changes on orbital timescales whereas internal dynamics of the climate system play an important role on shorter timescales interannual sst variability is linked to ocean atmosphere interactions of atlantic and pacific origin pronounced interannual variability in the western tropical atlantic is indicated by a 2 35 ka coral possibly related to a strengthening of the variability of the el nino southern oscillation throughout the holocene prominent inter to multidecadal sst variability is evident in the coral records and slightly more pronounced in the mid holocene we finally argue that our coral data provide a target for studying holocene climate variability on seasonal and interannual to multidecadal timescales when using further numerical models and high resolution proxy data

long and middle term behaviour of the tilt and strain variations in the decade following the 1976 friuli earthquake in ne italy tilt and strainmeter data collected in the friuli seismic area between 1977 and 1985 have been analyzed to study the stress strain field and or the elastic parameter variations in the area after the strong 1976 seismic event

last interglacial temperature seasonality reconstructed from tropical atlantic corals abstract reconstructions of last interglacial lig mis 5e 127 117 ka climate offer insights into the natural response and variability of the climate system during a period partially analogous to future climate change scenarios we present well preserved fossil corals diploria strigosa recovered from the southern caribbean island of bonaire caribbean netherlands these have been precisely dated by the 230 th u method to between 130 and 120 ka ago annual banding of the coral skeleton enabled construction of time windows of monthly resolved strontium calcium sr ca temperature proxy records in conjunction with a previously published 118 ka coral record our eight records of up to 37 years in length cover a total of 105 years within the lig period from these sea surface temperature sst seasonality and variability in the tropical north atlantic ocean is reconstructed we detect similar to modern sst seasonality of 2 9 c during the early 130 ka and the late lig 120 118 ka however within the mid lig a significantly higher than modern sst seasonality of 4 9 c at 126 ka and 4 1 c at 124 ka is observed these findings are supported by climate model simulations and are consistent with the evolving amplitude of orbitally induced changes in seasonality of insolation throughout the lig irrespective of wider climatic instabilities that characterised this period the climate model simulations suggest that the sst seasonality changes documented in our lig coral sr ca records are representative of larger regions within the tropical north atlantic these simulations also suggest that the reconstructed sst seasonality increase during the mid lig is caused primarily by summer warming a 124 ka old coral documents for the first time evidence of decadal sst variability in the tropical north atlantic during the lig akin to that observed in modern instrumental records

evaluating morphological estimates of the aerodynamic roughness of debris covered glacier ice aerodynamic roughness length z0 the height above the ground surface at which the extrapolated horizontal wind velocity profile drops to zero is one of the most poorly parameterised elements of the glacier surface energy balance equation microtopographic methods for estimating z0 have become prominent in the literature in recent years but are rarely validated against independent measures and are yet to be comprehensively analysed for scale or data resolution dependency here we present the results of a field investigation conducted on the debris covered khumbu glacier during the post monsoon season of 2015 we focus on two sites the first is characterised by gravels and cobbles supported by a fine sandy matrix the second comprises cobbles and boulders separated by voids vertical profiles of wind speed recorded by a tower comprising five cup anemometers and deployed over both sites enable us to derive measurements of aerodynamic roughness that reflect their observed surface characteristics 0 0184 m and 0 0243 m respectively at the second site z0 also varied through time following snowfall 0 0055 m and during its subsequent melt 0 0129 m showing the importance of fine resolution topography for near surface airflow to compare the wind profile data to microtopographic methods we conducted structure from motion multi view stereo sfm mvs surveys across each patch and calculated z0 using three previously published approaches the fully three dimensional cloud based approach is shown to be most stable across different scales and these z0 values are most correct in relative order when compared to the wind tower data popular profile based methods perform less well providing highly variable values across different scales and when using data of differing resolution these findings hold relevance for all studies using microtopographic methods to estimate aerodynamic roughness lengths including those in non glacial settings

importance of longwave emissions from adjacent terrain on patterns of tropical glacier melt and recession tropical glaciers constitute an important source of water for downstream populations however our understanding of glacial melt processes is still limited one observed process that has not yet been quantified for tropical glaciers is the enhanced melt caused by the longwave emission transfer here we use high resolution surface temperatures obtained from the thermal infrared imagery of the cuchillacocha glacier in the cordillera blanca peru in june 2014 to calculate a margin longwave flux this longwave flux reaching the glacier margin from the adjacent exposed rock varies between 81 and 120 w m 2 daily this flux is incorporated into a physically based melt model to assess the net radiation budget at the modeled glacier margin the simulation results show an increase in the energy available for melt by an average of 106 w m 2 during the day when compared with the simulation where the lw margin flux is not accounted for this value represents an increase in ablation of 1 7 m at the glacier margin for the duration of the dry season this study suggests that including the quantification of the glacier margin longwave flux in physically based melt models results in an improved assessment of tropical glacier energy budget and meltwater generation

on the role of subsurface heat conduction in glacier energy balance modelling we discuss the inclusion of the subsurface heat conduction flux into the calculation of the energy balance and ablation at the glacier atmosphere interface data from automatic weather stations are used to force an energy balance model at several locations on alpine glaciers and at one site in the dry andes of central chile the heat conduction flux is computed using a two layer scheme assuming that 36 of the net shortwave radiation is absorbed by the surface layer and that the rest penetrates into the snowpack we compare simulations conducted with and without subsurface heat flux results show that assuming a surface temperature of zero degrees leads to a larger overestimation of melt at the sites in the accumulation area 10 4 13 3 than in the ablation area 0 5 2 8 due to lower air temperatures and the presence of snow the difference between simulations with and without heat conduction is also high at the beginning and end of the ablation season up to 29 for the first 15 days of the season when air temperatures are lower and snow covers the glacier surface while they are of little importance during periods of sustained melt at all the locations investigated

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

measurements and interpretations of tilt strain gauges in seismically active areas abstract an overview of different aspects of deformation measurements is given an introduction to the general theory of point crustal deformations with an application to the stress strain relations at the earth surface is made the instrumentation used in crustal deformation measurements is briefly explained emphasizing different constructions of tilt and strainmeters the problems connected with the housing of the instruments i e the cavity and topography effects and with the ambient noise factors as the hydrological and pressure effects are discussed the last part of the paper is concerned with the relation between deformation measurements and seismic events both from a theoretical and observational standpoint a number of examples are shown that report on pre co and post seismic and the secular term deformation in different areas of the world

recent glacier retreat in the caucasus mountains russia and associated increase in supraglacial debris cover and supra proglacial lake development this paper reports changes in supraglacial debris cover and supra proglacial lake development associated with recent glacier retreat 1985 2000 in the central caucasus mountains russia satellite imagery landsat tm and etm was used to map the surface area and supraglacial debris cover on six neighbouring glaciers in the adylsu valley through a process of manual digitizing on a false colour composite of bands 5 4 3 red green blue the distribution and surface area of supraglacial and proglacial lakes was digitized for a larger area which extended to the whole landsat scene we also compare our satellite interpretations to field observations in the adylsu valley supraglacial debris cover ranges from 25 on individual glaciers but glacier retreat between 1985 and 2000 resulted in a 3 6 increase in the proportion of each glacier covered by debris the only exception to this trend was a very small glacier where debris cover did not change significantly and remote mapping proved more difficult the increase in debris cover is characterized by a progressive up glacier migration which we suggest is being driven by focused ablation and therefore glacier thinning at the up glacier limit of the debris cover resulting in the progressive exposure of englacial debris glacier retreat has also been accompanied by an increase in the number of proglacial and supraglacial lakes in our study area from 16 in 1985 to 24 in 2000 representing a 57 increase in their cumulative surface area these lakes appear to be impounded by relatively recently lateral and terminal moraines and by debris deposits on the surface of the glacier the changes in glacier surface characteristics reported here are likely to exert a profound influence on glacier mass balance and their future response to climate change they may also increase the likelihood of glacier related hazards lake outbursts debris slides and future monitoring is recommended

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

a physically based method for estimating supraglacial debris thickness from thermal band remote sensing data in order to account for the effects of debris cover in model scenarios of the response of glaciers to climate change and water resource planning it is important to know the distribution and thickness of supraglacial debris and to monitor its change over time previous attempts to map surface debris thickness using thermal band remote sensing have relied upon time specific empirical relationships between surface temperature and thickness limiting their general applicability in this paper we develop a physically based model that utilizes advanced spaceborne thermal emission and reflection radiometer aster thermal band remotely sensed imagery and is based on a solution of the energy balance at the debris surface the model is used to estimate debris thickness on miage glacier italy and is validated using field debris thickness measurements and a previously published debris thickness map the temporal transferability of the model is demonstrated through successful application to a separate aster image from a different year using reanalysis meteorological input data this model has the potential to be used for regional scale supraglacial debris thickness mapping and monitoring for debris up to at least 0 50 m thickness but improved understanding of the spatial patterns of air temperature aerodynamic roughness length and thermal properties across debriscovered glaciers is needed

on multidecadal variability of the atlantic meridional overturning circulation in the community climate system model version 3 abstract multidecadal variability of the atlantic meridional overturning circulation moc is investigated diagnostically in the ncar community climate system model version 3 ccsm3 present day simulations using the highest t85 1 resolution version this variability has a 21 yr period and is present in many other ocean fields in the north atlantic in moc the oscillation amplitude is about 4 5 sv 1 sv 106 m3 s 1 corresponding to 20 of the mean maximum moc transport the northward heat transport nht variability has an amplitude of about 0 12 pw representing 10 of the mean maximum nht in sea surface temperature sst and sea surface salinity sss the peak to peak changes can be as large as 6 7 c and 3 psu respectively the labrador sea region is identified as the deep water formation dwf site associated with the moc oscillations in contrast with some previous studies temperature and salinity contributions to the total density in this dwf region are almost equal and in phase the he

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

mass balance estimates for haut glacier d arolla switzerland from 2000 to 2006 using dems and distributed mass balance modeling a distributed mass balance modeling approach is required to assess the impact of future climate scenarios on water availability in glaciated basins accurate estimation of water stored within the snow firn and ice of such basins requires knowledge of the distributed snow and ice mass balance throughout the year in this study we estimate the annual mass balance and runoff for haut glacier darolla switzerland from 2000 to 2006 our estimations are based on observed elevation changes from three digital elevation models dems derived from aerial photographs in september 1999 and 2005 and october 2006 in addition to these estimations we implement a combined field observation and a distributed mass balance modeling approach an energy balance model driven by meteorologi cal variables from automatic weather stations inside the catchment area including gravitational snow transport is run for the period 2005 06 the model results are validated with direct snow water equiv alent measurements as well as with runoff measurements combining the mass balance measurements energy balance calculations and measured runoff we estimate the contribution from ice melt to the runoff for this period to be 25 30 the contribution from snowmelt 50 60 and the contribution from rain 15 25 our model results also show that the snow distribution affects both snow and ice melt it is therefore important for water resources management to understand the distribution of snow in alpine catchments as it seems to be the controlling factor for the timing of streamflow throughout the year as well as for the total availability of water

a distributed surface energy balance model for a small valley glacier i development and testing for haut glacier d arolla valais switzerland this paper describes the development and testing of a distributed surface energy balance model used to calculate rates of surface melting at haut glacier d arolla valais switzerland the model uses a digital elevation model dem of the glacier surface and surrounding topography together with meteorological data collected at a site in front of the glacier to determine hourly or daily totals of the energy balance components and hence of melting over the entire surface of the glacier with a spatial resolutio of 20 m the model can also be used to determine temporal and spatial variations in snow depth snow line position and glacier surface albedo calculations from the model are compared with observations made along the glacier centre line in 1990 and in general the model performs very well the correlation coefficients between calculated and measured snow line elevation albedo and ablation are 0 99 0 85 and 0 81 respectively the main source of error between modelled and measured values of these variables is probably inadequacies in the parameterization of albedo used in the model

the temporal significance of transitions from melting to calving termini at glaciers in the central southern alps of new zealand termini of valley glaciers in the central southern alps are undergoing a three phase sequence of retreat that began in the 1950s an initial phase of melting and slow downwasting under thickening supraglacial debris mantles is associated with stationary or slowly retreating termini this is followed by a transitional phase of disruption of insulating debris mantles allowing the rapid growth of shallow thermokarst lakes the shape and location of which vary according to glacier gradient and marginal topography a third phase of rapid calving retreat of ice cliffs into deepening proglacial lakes develops from the transitional phase at no stage are terminal responses simply related to climate present transitions to calving retreat are related to the morphology of glacier termini particularly to large outwash heads landform evidence indicates that similar calving phases do not appear to have occurred since late pleistocene deglaciation so that present changes to glacier termini are of great significance

including debris cover effects in a distributed model of glacier ablation 1 distributed glacier melt models generally assume that the glacier surface consists of bare exposed ice and snow in reality many glaciers are wholly or partially covered in layers of debris that tend to suppress ablation rates in this paper an existing physically based point model for the ablation of debris covered ice is incorporated in a distributed melt model and applied to haut glacier d arolla switzerland which has three large patches of debris cover on its surface the model is based on a 10 m resolution digital elevation model dem of the area each glacier pixel in the dem is defined as either bare or debris covered ice and may be covered in snow that must be melted off before ice ablation is assumed to occur each debris covered pixel is assigned a debris thickness value using probability distributions based on over 1000 manual thickness measurements locally observed meteorological data are used to run energy balance calculations in every pixel using an approach suitable for snow bare ice or debris covered ice as appropriate the use of the debris model significantly reduces the total ablation in the debris covered areas however the precise reduction is sensitive to the temperature extrapolation used in the model distribution because air near the debris surface tends to be slightly warmer than over bare ice overall results suggest that the debris patches which cover 10 of the glacierized area reduce total runoff from the glacierized part of the basin by up to 7

spells of low frequency oscillations and weather regimes in the northern hemisphere abstract the low frequency variability in the midlatitudes is described through an analysis of the oscillatory phenomena in order to isolate nearly periodic components of the atmospheric flow the multichannel version of the singular spectrum analysis m ssa is developed and applied to an nmc 32 year long set of 700 hpa geopotential heights in the same way that principal component analysis identifies the spatial patterns dominating the variability m ssa identifies dynamically relevant space time patterns and provides an adaptive filtering technique three major low frequency oscillations lfos are found with periods of 70 days 40 45 days and 30 35 days the 70 day oscillation consists of fluctuations in both position and amplitude of the atlantic jet with a poleward propagating anomaly pattern the 40 45 day oscillation is specific to the pacific sector and has a pronounced pacific north american pna structure in its high amplitude phase the 30 35 day mode is confined over the atlantic region

georeferenced thermal infrared images from uav surveys as a potential tool to detect and characterize shallow cave ducts abstract caves are buried geological features of great scientific and engineering interest based on the well known thermal inertia of cave settings with respect to the surface we have tested the use of thermal infrared tir cameras carried by unmanned aerial vehicles uavs to identify and characterize shallow karstic conduits a pilot area was selected in a limestone rock massif from the betic cordillera southern spain at surface this area appears as a doline field with several explored shaft entrances the main and deepest shaft was thermally monitored at different depths showing two well defined seasonal stages i air and temperature stratification in summer and ii upward air flow and temperature homogenization in winter we carried out uav surveys at the expected maximum thermal contrast hours finding out that winter dawns yielded the most distinctive images these images show new warm air exits warm spots apart from the known cave entrances and emphasize some of the main entrances depicting large warmed areas around them which in turn can be related to shallow voids and conduits in the cave system furthermore tir images have been georeferenced using a network of identifiable points that can be transferred from visible orthoimages the resulting tir orthoimage mosaics have allowed us to define a number of quantitative parameters to characterize the warm spots the most important of these parameters are i the characteristic temperature which is the maximum significant temperature of the air escaping from cave openings ii the warmed area which is the area that appears on the tir orthoimage with a temperature greater than the surface temperature mode and iii the average temperature weighted to the affected area the georeferenced tir orthoimages and the derived parameters are a new and very valuable tool for both speleological exploration and engineering purposes

estimation of debris cover and its temporal variation using optical satellite sensor data a case study in chenab basin himalaya debris cover over glaciers greatly affects their rate of ablation and is a sensitive indicator of glacier health this study focuses on estimation of debris cover over samudratapu glacier chenab basin himalaya using optical remote sensing data remote sensing image data of irs 1c liss iii september 2001 irs p6 awifs september 2004 and terra aster september 2004 along with survey of india topographical maps 1963 were used in the study supervised classification of topographically corrected reflectance image data was systematically conducted to map six land cover classes in the glacier terrain snow ice mixed ice and debris debris valley rock and water an accuracy assessment of the classification was conducted using the aster visible near infrared data as the reference the overall accuracies of the glacier cover maps were found to range from 83 7 to 89 1 whereas the individual class accuracy of debris cover mapping was found to range from 82 to 95 this shows that supervised classification of topographically corrected reflectance data is effective for the extraction of debris cover in addition a comparative study of glacier cover maps generated from remote sensing data supervised classification of september 2001 and september 2004 and survey of india topographical maps 1963 has highlighted the trends of glacier depletion and recession the glacier snout receded by about 756 m from 1963 to 2004 and the total glacier area was reduced by 13 7 km 2 from 110 km 2 in 1963 further glacier retreat is found to be accompanied by a decrease in mixed ice and debris and a marked increase in debris cover area the area covered by valley rock is found to increase confirming an overall decrease in the glacier area the results from this study demonstrate the applicability of optical remote sensing data in monitoring glacier terrain and particularly mapping debris cover area

modelling seasonal and spatial variations in the surface energy balance of haut glacier d arolla switzerland the impact of spatial and temporal variations in the surface albedo and aerodynamic roughness length on the surface energy balance of haut glacier d arolla switzerland was examined using a semi distributed surface energy balance model arnold and others 1996 the model was updated to incorporate the glacier wide effects of albedo and aerodynamic roughness length variations using parameterizations following brock 1997 after the model s performance was validated the glacier wide patterns of the net shortwave turbulent and melt energy fluxes were examined on four days representative of surface conditions in late may june july and august in the model meteorological conditions were held constant on each day in order that the impact of albedo and aerodynamic roughness length variations could be assessed independently a late summer snowfall event was also simulated albedo and aerodynamic roughness length variations particularly those associated with the migration of the transient snowline and the decay of the winter snowpack were found to exert a strong influence on the magnitude of the surface energy fluxes the importance of meteorological conditions in suppressing the surface energy fluxes and melt rate following a fresh snowfall was highlighted

long term crustal deformations in ne italy revealed by tilt strain gauges abstract tilt and strain gauge records are analysed to determine the long term variations in space and time of the strain field in the friuli area ne italy located at the eastern boundary of the adria plate for such long term variations a deep crustal origin is supposed spectral and cross correlation analyses show that the strain energy involving a large area is polarized in two main directions n20w and n70e the first one characterized by aperiodic or very long period undetectable by the present analysis variations the second one by a period of about 8 years the direction of the aperiodic motion n20w is normal to the alpine chain and parallel to the maximum horizontal compression acting in the alpine area whereas the direction of the 8 year period motion n70e is normal to the dinaric alps chain and coincident with the maximum horizontal compression acting on the eastern boundary of the adria plate in the balkans region to explain such results and particularly those related to the n70e direction slow travelling stress strain waves are hypothesized

measuring glacier surface temperatures with ground based thermal infrared imaging spatially distributed surface temperature is an important yet difficult to observe variable for physical glacier melt models we utilize ground based thermal infrared imagery to obtain spatially distributed surface temperature data for alpine glaciers the infrared images are used to investigate thermal microscale processes at the glacier surface such as the effect of surface cover type and the temperature gradient at the glacier margins on the glacier s temperature dynamics infrared images were collected at cuchillacocha glacier cordillera blanca peru on 23 25 june 2014 the infrared images were corrected based on ground truth points and local meteorological data for the control points the pearson s correlation coefficient between infrared and station temperatures was 0 95 the ground based infrared camera has the potential for greatly improving glacier energy budget studies and our research shows that it is critical to properly correct the thermal images to produce robust quantifiable data

evidence for variations of mechanical properties in the friuli seismic area abstract tidal strains of the earth were extracted from three horizontal strainmeter records 1979 1986 in the friuli seismic area by the filter method the areal strain factor ignoring the tidal loading effects shows that its time variation is significant their amplitudes in 1986 are about 50 of those in 1979 the modifications of mechanical properties estimated in terms of the local shear and bulk modulus variations were obtained considering the envelope of the tidal strain signals the seismic wave velocity determined by the simultaneous inversion of the arrival time data of the local seismometric network displayed comparable changes a major change both in the seismic velocities and the elastic parameters started in march 1982 which was about 11 months before an earthquake of magnitude 4 1 the largest event from 1979 to 1986 which occurred within the seismic network on feb 10 1983

spatial and temporal melt variability at helheim glacier east greenland and its effect on ice dynamics this is the publisher s version also available electronically from http onlinelibrary wiley com

a quasi decadal cycle in caribbean climate 1 climatic variables in the period from 1951 to 2000 are analyzed across the tropics from the east pacific to africa a quasi decadal mode is isolated using singular value decomposition svd applied to monthly smoothed and detrended rainfall sea surface temperature sst sea level pressure slp and 200 hpa zonal u wind anomalies seven to 10 year cycles in caribbean rainfall are revealed as the dominant mode 50 variance and are found to be related to a mode of tropical variability that is distinct from previously known global signals sources of this signal include east atlantic sst and the northern subtropical ridge which modulate upwelling off venezuela svd analysis of daily rainfall suggests interaction between annual and quasi decadal signals with northern summer convection as a driver the second mode of caribbean rainfall variability derives from the east pacific el nino southern oscillation enso 21 variance that is expressed as an east west dipole of convection across the caribbean composite analysis of rainfall for high and low phases of the quasi decadal cycle reveals a corresponding signal that extends from the eastern pacific ocean across the caribbean and west africa to india the southern hadley cell spins up during wet phase and the itcz migrates northward this hemispheric scale anomaly brings pulses of convection to the caribbean impacts of the quasi decadal cycle on socioeconomic resources are investigated

interannual and intra annual variability of rainfall in haiti 1905 2005 the interannual variability of annual and monthly rainfall in haiti is examined from a database of 78 rain gauges in 1905 2005 the spatial coherence of annual rainfall is rather low which is partly due to haiti s rugged landscape complex shoreline and surrounding warm waters mean sea surface temperatures 27 c from may to december the interannual variation of monthly rainfall is mostly shaped by the intensity of the low level winds across the caribbean sea leading to a drier or wetter than average rainy season associated with easterly or westerly anomalies increasing or decreasing winds the varying speed of low level easterlies across the caribbean basin may reflect at least four different processes during the year 1 an anomalous trough ridge over the western edge of the azores high from december to february peaking in january 2 a zonal pressure gradient between eastern pacific and the tropical northern atlantic from may june to september with a peak in august i e lower than average rainfall in haiti is associated with positive sea level pressure anomalies over the tropical north atlantic and negative sea level pressure anomalies over the eastern pacific 3 a local ocean atmosphere coupling between the speed of the caribbean low level jet and the meridional sea surface temperature sst gradient across the caribbean basin i e colder than average sst in the southern caribbean sea is associated with increased easterlies and below average rainfall in haiti this coupling is triggered when the warmest caribbean waters move northward toward the gulf of mexico 4 in october november a drier or wetter than usual rainy season is related to an almost closed anticyclonic or cyclonic anomaly located ene of haiti on the sw edge of the azores high this suggests a main control of the interannual variations of rainfall by intensity track and or recurrence of tropical depressions traveling northeast of haiti during this period the teleconnection of haitian rainfall with synchronous atlantic and eastern pacific sst is at a minimum

first estimates of the principal directions of strains compared to those of stresses in seismic friuli ne italy three cambridge wire strainmeters and a pair of horizontal pendulum tiltmeters operate since 1978 in a cave in the northern friuli seismic area straightforward considerations based on the principles of continuum mechanics permit a first estimate of the secular and seasonal variations of the cave strain rate tensor under the assumption of homogeneous constant volume strain together with an analysis of the effects on the tensor components of particular tiltmeter installation sites with respect to the orientation of both the strainmeters plane and the principal axes

comparison of a three dimensional model for glacier flow with field data from haut glacier d arolla switzerland a three dimensional finite difference model based on a first order solution of the ice flow equations is applied to haut glacier d arolla switzerland the numerical model successfully converges at horizontal resolutions down to 70 m so a number of detailed comparisons with field data can be made modelled surface velocities with no basal sliding component are compared with surface velocities observed on the glacier over four different time periods the best fit is achieved with over winter surface velocities r 2 0 75 using a rate factor a in glen s flow law of 0 063 a 1 bar 3 surface zones of maximum computed effective stress display a high level of coincidence with observed crevassing the orientation of which is successfully predicted by the direction of the tensile component of the computed principal surface stress comparison of the relative magnitude and direction of computed principal stresses with principal strains measured at the ice surface also correspond closely in an attempt to simulate the observed annual velocity distribution within a cross section of the glacier tongue we incorporate two basal motion patterns into the model by treating net annual ice motion as a time weighted composite of three separate flow situations normal sliding enhanced sliding and no sliding we are able to reproduce the key features of the observed cross sectional ice and basal slip velocity distributions these experiments indicate there may be substantial decoupling taking place along an elongated narrow zone at the bed of haut glacier d arolla and that this decoupling interacts in a complex manner with the englacial stress and strain field

precise emissivity of rock samples to differentiate among geological materials and vegetation using thermal infrared spectra radiometric measurements require corrections for local temperature variations and reflected radiation a laboratory technique is described for the determination of spectral emissivity signatures for natural geological samples using a fourier transform infrared spectrometer and the self emission of the scene the approach described does not require control of the sample temperature a quantitative assessment of uncertainties is presented comparison of the emissivity measurements from natural geological specimens with hemispherical reflectance data gave an average difference of about 0 01 in emissivity except near strong features of the spectra the technique is applicable to field measurements of high emissivity objects

spatial and temporal transferability of a distributed energy balance glacier melt model abstract modeling melt from glaciers is crucial to assessing regional hydrology and eustatic sea level rise the transferability of such models in space and time has been widely assumed but rarely tested to investigate melt model transferability a distributed energy balance melt model debm is applied to two small glaciers of opposing aspects that are 10 km apart in the donjek range of the st elias mountains yukon territory canada an analysis is conducted in four stages to assess the transferability of the debm in space and time 1 locally derived model parameter values and meteorological forcing variables are used to assess model skill 2 model parameter values are transferred between glacier sites and between years of study 3 measured meteorological forcing variables are transferred between glaciers using locally derived parameter values 4 both model parameter values and measured meteorological forcing variables are transferred from one glacier site to the other treating the second glacier

climate sensitivity of a high precipitation glacier in new zealand the sensitivity of glaciers to climatic change is key information in assessing the response and sea level implications of projected future warming new zealand glaciers are important globally as an example of how maritime glaciers will contribute to sea level rise a spatially distributed energy balance model is applied to brewster glacier new zealand in order to calculate glacier mass balance run off and sensitivity to climate change the model successfully simulates four annual mass balance cycles close to half 52 of the energy available for melt on the glacier is supplied by turbulent heat fluxes with radiation less important except during the winter model sensitivity to temperature change is one of the largest reported on earth at 2 0 m w e a 1 8c 1 in contrast a 50 change in precipitation is required to offset the mass balance change resulting from a 18c temperature change meltwater run off sensitivity is also very high increasing 60 with a 18c warming the extreme sensitivity of mass balance to temperature change suggests that significant ice loss will occur with even moderate climate warming

the dependence of caribbean rainfall on the interaction of the tropical atlantic and pacific oceans abstract seasonally stratified analyses of rainfall anomalies over the intra americas sea and surrounding land areas and of onset and end dates of the central american rainy season show that the variability of the tropical atlantic sea surface temperature anomaly ssta is more strongly associated with rainfall over the caribbean and central america than is tropical eastern pacific ssta seasonal differences include the importance of antisymmetric configurations of tropical atlantic ssta in the dry season but not in the rainy season both oceans are related to rainfall but the strength of the rainfall response appears to depend on how ssta in the tropical atlantic and eastern pacific combine the strongest response occurs when the tropical atlantic is in the configuration of a meridional dipole antisymmetric across the itcz and the eastern tropical pacific is of opposite sign to the tropical north atlantic when the tropical north atlantic and tropical pacific are of the same sign the rainfall respons

planimetric and volumetric glacier changes in the khumbu himal nepal since 1962 using corona landsat tm and aster data multitemporal space imagery from 1962 corona kh 4 1992 landsat tm 2001 and 2005 terra aster was used to investigate the glacier changes in the khumbu himal nepal the ice coverage in the investigation area decreased by about 5 between 1962 and 2005 with the highest retreat rates occurring between 1992 and 2001 the debris coverage increased concomitantly with the decrease in total glacier area the clean ice area decreased by 10 digital terrain model dtm generation from the early corona kh 4 stereo data in this high relief terrain is time consuming and the results still contain some elevation errors however these are minor in the snow free areas with gentle slopes thus comparison of the surfaces of the debris covered glacier tongues based on the corona dtm and an aster dtm is feasible and shows the downwasting of the debris covered glaciers the highest downwasting rates more than 20 m 0 5 m a 1 can be found near the transition zone between the active and the stagnant glacier parts of the debris covered glacier tongues the downwasting is lower but still evident in the active ice areas and at the snout with thick debris cover all investigated debris covered glaciers in the study area show similar behaviour the estimated volume loss for the investigated debris covered glacier tongues is 0 19 km 3

an enhanced temperature index glacier melt model including the shortwave radiation balance development and testing for haut glacier d arolla switzerland an enhanced temperature index glacier melt model incorporating incoming shortwave radiation and albedo is presented the model is an attempt to combine the high temporal resolution and accuracy of physically based melt models with the lower data requirements and computational simplicity of empirical melt models represented by the degree day method and its variants the model is run with both measured and modelled radiation data to test its applicability to glaciers with differing data availability five automatic weather stations were established on haut glacier d arolla switzerland between may and september 2001 reference surface melt rates were calculated using a physically based energy balance melt model the performance of the enhanced temperature index model was tested at each of the four validation stations by comparing predicted hourly melt rates with reference melt rates predictions made with three other temperature index models were evaluated in the same way for comparison the enhanced temperature index model offers significant improvements over the other temperature index models and accounts for 90 95 of the variation in the reference melt rate the improvement is lower but still significant when the model is forced by modelled shortwave radiation data thus offering a better alternative to existing models that require only temperature data input

an energy balance model for debris covered glaciers including heat conduction through the debris layer extensive covers of supraglacial debris are often present in glacier ablation areas and it is essential to assess exactly how the debris affects glacier melt rates this paper presents a physically based energy balance model for the surface of a debris covered glacier the model is driven by meteorological variables and was developed using data collected at miage glacier italy during the ablation seasons of 2005 2006 and 2007 the debris surface temperature is numerically estimated by considering the balance of heat fluxes at the air debris interface and heat conduction through the debris is calculated in order to estimate melt rates at the debris ice interface the predicted hourly debris surface temperatures and debris internal temperatures provide a good fit to temperatures measured on rock covered miage glacier r 2 0 94 and the tephra covered glacier on villarrica volcano chile r 2 0 82 the model can also be used to reproduce observed changes in melt rates below debris layers of varying types and thicknesses an important consideration for the overall mass balance of debris covered glaciers

boundary layer integration approach to advection of sensible heat to a patchy snow cover in the calculation of the melting of a patchy snow cover the energy advected from the adjacent bare soil to the snow surface is an important consideration the quantity or rate of energy advected depends on the fetches and sizes of snow and bare ground patches any successful method to estimate advection will necessarily require the incorporation of relationships describing the same complex boundary layer methods require detailed spatial knowledge of the patch sizes wind direction and fetch distances and are computationally intensive a physically based approach that can be spatially applied using distributions of snow patch geometry is required this paper presents a new approach in which boundary layer integration is used to provide a means of calculating the amount of energy removed by the snow patch surface as warmer air moves over it the method is reduced to a simple parametric form and the relationships describing the coefficients required for its application are developed the applicability of this new approach is discussed in light of the fractal nature of snow patches the relationship between the individual patch length and area and the distribution of patch sizes as they develop and disappear on the landscape

a distributed energy balance melt model of an alpine debris covered glacier distributed energy balance melt models have rarely been applied to glaciers with extensive supraglacial debris cover this paper describes the development of a distributed melt model and its application to the debris covered miage glacier western italian alps over two summer seasons sub debris melt rates are calculated using an existing debris energy balance model deb model and melt rates for clean ice snow and partially debris covered ice are calculated using standard energy balance equations simulated sub debris melt rates compare well to ablation stake observations melt rates are highest and most sensitive to air temperature on areas of dirty crevassed ice on the middle glacier here melt rates are highly spatially variable because the debris thickness and surface type varies markedly melt rates are lowest and least sensitive to air temperature beneath the thickest debris on the lower glacier debris delays and attenuates the melt signal compared to clean ice with peak melt occurring later in the day with increasing debris thickness the continuously debris covered zone consistently provides 30 of total melt throughout the ablation season with the proportion increasing during cold weather sensitivity experiments show that an increase in debris thickness of 0 035 m would offset 1 c of atmospheric warming

calculating ice melt beneath a debris layer using meteorological data generalized numerical models of sub debris ice ablation are preferable to empirical approaches for predicting runoff and glacier response to climate change as empirical methods are site specific and strongly dependent upon the conditions prevailing during the measurement period we present a modified surface energy balance model to calculate melt beneath a surface debris layer from daily mean meteorological variables despite numerous simplifications the model performs well and modelled melt rates give a good match to observed melt rates suggesting that this model can produce reliable estimates of ablation rate beneath debris layers several decimetres thick this is a useful improvement on previous models which are inappropriate for thick debris cover

on the evolution of the thermocline and subthermocline eastward currents in the equatorial atlantic 1 eastward currents in the thermocline and subthermocline layers of the tropical atlantic ocean are described using observations obtained during two boreal summer cruises covering the whole equatorial basin the analysis focuses on the eastward evolution of zonal currents in the thermocline and sub thermocline the equatorial undercurrent is not found close to the african coast in boreal summer 2000 maybe because of interannual variability as observed in the pacific the south and north equatorial undercurrents are shown to shift poleward from west to east and the two cruises indicate that the north equatorial undercurrent does not enter the gulf of guinea the south and north intermediate countercurrents are variable with longitude and contrarily to the observations in the eastern equatorial pacific are not found in the east of the guinea basin

the midsummer drought over mexico and central america abstract the annual cycle of precipitation over the southern part of mexico and central america exhibits a bimodal distribution with maxima during june and september october and a relative minimum during july and august known as the midsummer drought msd the msd is not associated with the meridional migration of the intertropical convergence zone itcz and its double crossing over central america but rather with fluctuations in the intensity and location of the eastern pacific itcz during the transition from intense to weak weak to intense convective activity the trade winds over the caribbean strengthen weaken such acceleration in the trade winds is part of the dynamic response of the low level atmosphere to the magnitude of the convective forcing in the itcz the intensification of the trade winds during july and august and the orographic forcing of the mountains over most of central america result in maximum precipitation along the caribbean coast and minimum precipitation along the pacific

environmental patterns associated with active and inactive caribbean hurricane seasons this study of hurricanes passing through the caribbean in the 1950 2005 period reveals that seasons with more intense hurricanes occur with the onset of pacific la nina events and when atlantic ssts west of africa are above normal composites of ncep reanalysis fields with regard to caribbean hurricanes reveal de velopment of an anomalous equatorial atlantic zonal overturning circulation upper easterly lower westerly that shifts toward the caribbean coincident with a westward spread of the cold tongue in the east pacific ocean atmosphere coupling is promoted through interaction of the southern hadley cell and the atlantic itcz a heat budget analysis suggests that evaporation governs ssts in the major development region mdr and near venezuela but the signal is weak prior to may using the knowledge gained statistical algorithms are developed to predict caribbean hurricanes at seasonal lead times these make use of equa torial pacific sst subtropical atlantic sst and the zonal walker cell over the atlantic

toward hydro social modeling merging human variables and the social sciences with climate glacier runoff models santa river peru summary glacier shrinkage caused by climate change is likely to trigger diminished and less consistent stream flow in glacier fed watersheds worldwide to understand model and adapt to these climate glacier water changes it is vital to integrate the analysis of both water availability the domain of hydrologists and water use the focus for social scientists drawn from a case study of the santa river watershed below peru s glaciated cordillera blanca mountain range this paper provides a holistic hydro social framework that identifies five major human variables critical to hydrological modeling because these forces have profoundly influenced water use over the last 60 years 1 political agendas and economic development 2 governance laws and institutions 3 technology and engineering 4 land and resource use and 5 societal responses notable shifts in santa river water use including major expansions in hydroelectricity generation large scale irrigation projects and other land and resource use practices did not necessarily stem from changing glacier runoff or hydrologic shifts but rather from these human variables ultimately then water usage is not predictable based on water availability alone glacier runoff conforms to certain expected trends predicted by models of progressively reduced glacier storage however societal forces establish the legal economic political cultural and social drivers that actually shape water usage patterns via human modification of watershed dynamics this hydro social framework has widespread implications for hydrological modeling in glaciated watersheds from the andes and alps to the himalaya and tien shan as well as for the development of climate change adaptation plans