upper ocean response to typhoon choi wan as measured by the kuroshio extension observatory mooring 1 the kuroshio extension observatory keo is a highly instrumented moored reference station located at 32 3 n 144 5 e in the recirculation gyre south of the kuroshio extension on 19 september 2009 the eye of typhoon choi wan international designation 0914 passed 40 km to the southeast of the keo surface mooring hourly meteorological and physical oceanographic measurements together with 3 hourly air sea carbon dioxide observations telemetered from keo in near real time show the evolution of the upper ocean and its associated air sea fluxes during the passage of this storm and its aftermath during the approach of the storm the mixed layer freshened because of intense rainfall this was followed by a large outgassing of co2 rapid cooling and an increase in salinity although these changes in mixed layer properties imply substantial entrainment they were accompanied by upwelling and ultimately a temporary 20 m shoaling of the mixed layer this upwelling which was observed at all depths including the deepest sensor near 500 m was coincident with the onset of near inertial oscillations in the mixed layer currents after the typhoon passed inertial pumping caused 15 20 m amplitude vertical displacements throughout the top 500 m that continued for at least 6 days a large oceanic response was observed in this case even though the eye of choi wan passed to the right of keo resulting in winds rotating cyclonically with time in opposition to the anticyclonic rotating near inertial currents

air sea interactions during an arctic storm 1 the impacts of increased open water in the beaufort sea were investigated for a summer arctic storm in 2008 using a coupled atmosphere ice ocean model the storm originated in northern siberia and slowly moved into the beaufort sea along the ice edge in late july the maximum wind associated with the storm occurred when it was located over the open water near the beaufort sea coast after it had moved over the chukchi and beaufort seas the coupled model system is shown to simulate the storm track intensity maximum wind speed and the ice cover well the model simulations suggest that the lack of ice cover in the beaufort sea during the 2008 storm results in increased local surface wind and surface air temperature compared to enhanced ice cover extents such as occurred in past decades in addition due to this increase of open water the surface latent and sensible heat fluxes into the atmosphere are significantly increased however there were no significant impacts on the storm track the expanded open water and the loss of the sea ice results in increases in the surface air temperature by as much as 8 c although the atmospheric warming mostly occurs in the boundary layer there is increased atmospheric boundary turbulence and downward kinetic energy transport that reach to mid levels of the troposphere and beyond these changes result in enhanced surface winds by as much as 4 m s during the 2008 storm compared to higher ice concentration conditions typical of past decades the dominant sea surface temperature response to the storm occurs over open water storm generated mixing in the upper ocean results in sea surface cooling of up to 2 c along the southern beaufort sea coastal waters the ekman divergence associated with the storm caused a decrease in the fresh water content in the central beaufort sea by about 11 cm

analyses and simulations of the upper ocean s response to hurricane felix at the bermuda testbed mooring site 13 23 august 1995 causedalargeincreaseinkineticenergyatnear inertialfrequencies internalgravitywavesin the thermocline and inertial pumping mixed layer deepening and significant vertical redistribution of heat with cooling of the upper 30 m and warming at depths of 30 70 m the temperature evolution was simulated using four one dimensional mixed layer models price weller pinkel pwp k profile parameterization kpp mellor yamada 2 5 my and a modified version of my2 5 my2 the primary differences in the model results were in their simulations of temperature evolution in particular when forced using a drag coefficient thathadalinear dependenceonwindspeed the kppmodelpredicted seasurface cooling mixed layer currents and the maximum depth of cooling closer to the observations than any of the other models this was shown to be partly because of a special parameterization for gradient richardson number rgkpp shear instability mixing in responsetoresolvedshearintheinterior themy2modelpredictedmoreseasurfacecooling and greater depth penetration of kinetic energy than the my model in the my2 model the dissipation rate of turbulent kinetic energy is parameterized as a function of a locally defined richardson number rgmy2 allowing for a reduction in dissipation rate for stable richardsonnumbers rgmy2 wheninternalgravitywavesarelikelytobepresent sensitivity simulations with the pwp model which has specifically defined mixing procedures show that most of the heat lost from the upper layer was due to entrainment parameterized as a function of bulk richardson number rbpwp with the remainder due to local richardson number rgpwp instabilities with the exception of the my model the models predicted reasonable estimates of the north and east current components during and after the hurricane passage at 25 and 45 m although the results emphasize differences between the modeled responsestoagivenwindstress currentcontroversyovertheformulationofwindstressfrom wind speed measurements including possible sea state and wave age and sheltering effects cautions against using our results for assessing model skill in particular sensitivity studies show that my2 simulations of the temperature evolution are excellent when the wind stress is increased albeit with currents that are larger than observed sensitivity experiments also indicate that preexisting inertial motion modulated the amplitude of poststormcurrents butthattherewasprobablynotasignificantresonantresponsebecauseof clockwise wind rotation for our study site index terms 4504 oceanography physical air sea interactions 0312 4572 oceanography physical upper ocean processes 4255 oceanography general numericalmodeling 4544oceanography physical internalandinertialwaves keywords hurricane tropical cyclone mixed layer modeling upper ocean processes inertial currents ocean storms

evaluation of mining induced energy and rockburst prediction at a diamond mine in canada using a full 3d elastoplastic finite element model abstract rockburst occurs when a volume of rock is strained beyond its elastic limit this type of failure is violent and instantaneous its occurrence is a major concern for the safety of underground personnel this paper reviews the current methods of rockburst prediction then a methodology is proposed to assess the extent and magnitude of the mining induced strain energy and its accumulation in a rock mass to predict the rockburst potentials in an underground mine both conventional and numerical methods have been combined to estimate the rockburst potentials in a real case study mine a case study of canadian diamond mine has been used to implement the proposed methodology site investigations have been conducted by traveling several times to the mine site and gathering essential data such as in situ stress states mining methods the geometry of underground openings mining and stoping sequences and rock mass classification kimberlite samples from both pipes have been collected for rock mechanics laboratory tests finally using the results of the numerical model two rockburst criteria ts and bpi have been used to assess the rockburst tendency in the understudy domain utilizing the proposed methodology potentially hazardous areas can be identified

barents sea seasonal ice zone features and processes from ers 1 synthetic aperture radar seasonal ice zone experiment 1992 sea ice features and processes in the barents sea were studied during the seasonal ice zone experiment 1992 sizex92 a dedicated ers 1 satellite synthetic aperture radar sar field campaign carried out in march 1992 sizex92 was based around the research vessels polarsyssel and hakon mosby in situ oceanographic meteorological and ice measurements were made coordinated with low altitude aerial observations and ers 1 sar data acquired in near real time fifty eight low and full resolution sar scenes were obtained during sizex92 which provided a validation data set for ers 1 sar backscatter under winter conditions in the barents sea analysis of sizex92 data has provided geophysical insights including a better understanding of barents sea ice edge freezing processes and ice edge development in response to atmospheric forcings in particular areas of new ice formation were found to be related to bathymetric features through their influence on the circulation of arctic and atlantic water masses ers 1 sar image sequences revealed rapid mesoscale variations in new ice areas and the ice edge in response to wind conditions in addition to geophysical insight sizex92 demonstrated some of the technical capabilities and limitations of ers 1 sar to identify new ice areas the ice edge ice floes and ice types mapping new ice areas using satellite sar data may be considered the most promising new application the limitations of ers 1 sar derived ice classification and ice motion estimates in the marginal ice zone are identified

recent current observations in the eastern yellow sea observations of current velocity pressure and temperature in the eastern yellow sea from january 10 through april 12 1986 together with geostrophic winds calculated from surface atmospheric pressure distributions are analyzed for a study of the synoptic band response of the yellow sea to the wintertime winds north wind pulses in the winter monsoon are found to give rise to northward flow bursts in the yellow sea trough which appear to peak just as the wind relaxes and to be driven by a synoptic band north to south rise in bottom pressure synchronous with the north wind pulses the existence of a similar rise in coastal sea level indicates that the observed southward pressure rise is but an offshore extension of a setup along the west coast of south korea forced by the north wind pulses the advection by northward flow bursts of warm water from the south apparently causes the measured temperature to be substantially higher in the trough than in coastal waters at the same latitude and the observed rate of cooling in the trough to be less than half of that in coastal waters to the east a winter to spring transition is also found in the bottom pressure records obtained in the trough in which the mean north to south gradient in winter reverses suddenly in early march a similar reversal also appears in sea level records along the west coast of south korea the reversal appears to be triggered by the weakening of the north winds at the arrival of spring

coastal wave generation in the bohai bay and propagation along the chinese coast the bohai bay and yellow sea experience sea surface height ssh changes of 20 cm and larger during wintertime northerly and southerly wind bursts that have a time scale of a few days these large ssh changes give rise to coastal shelf waves that subsequently propagate southward along the chinese coast two models provide observations of these waves the first one is a statistical model based on four years of topex poseidon t p altimeter ssh observations and navy operational global atmospheric prediction system nogaps wind stress fields the second model is a numerical model forced by the wind stress the numerical model provides an objective interpretation of the wind stress response based on dynamical equations the statistical model is based on observations with a linear response to the wind forcing and thus complements the numerical model the observed waves closely resemble gravest mode shelf waves derived by analytical solutions

measuring the sea ice floe size distribution sea ice is broken into floes whose diameters range from meters to a hundred kilometers this fragmentation affects the resistance of the ice cover to deformation and the melting at floe sidewalls in summer floes are broken by waves and swell near the ice edge and throughout the pack by isostatic imbalances thermal cracking winds and currents in winter they are welded together by freezing floe size can be measured by several properties p for instance area or mean caliper diameter two definitions of floe size distribution seem useful f p the fraction of area covered by floes no smaller than p and n p the number of floes per unit area no smaller than p f p can be measured by sets other than areas such as the fraction of a line or of a point set covered by floes no smaller than p if n behaves like for small where is mean caliper diameter must be greater than 2 so that the small floes occupy finite area if 2 1 the perimeter of small floes is infinite several summertime distributions have been measured on a log log graph their slopes local values of range from 1 7 to 2 5 one distribution follows a power law the others have steeper slopes for larger floes and more gradual slopes for smaller floes another sampling strategy is to measure the lengths of line segments on floes the distribution of these chord lengths is equivalent to the distribution of floe diameters the variance of an estimate of the fraction g of area covered by floes in any size range is g 1 g k 1 where k is the equivalent number of independent samples k can be found from the autocovariance of the indicator function for the chosen size range for line sampling of a narrow range of floe diameters k is the ratio of the sample length to the floe diameter

wind and wave influences on sea ice floe size and leads in the beaufort and chukchi seas during the summer fall transition 2014 sea ice floe size distribution and lead properties in the beaufort and chukchi seas are studied in the summer fall transition 2014 to examine the impact on the sea ice cover from storms and surface waves floe size distributions are analyzed from medea landsat8 and radarsat 2 imagery with a resolution span of 1 100 m landsat8 imagery is also used to identify the orientation and spacing of leads the study period centers around three large wave events during august september 2014 identified by swift buoys and wavewatch iii model data the range of floe sizes from different resolutions provides the overall distribution across a wide range of ice properties and estimated thickness all cumulative floe size distribution curves show a gradual bending toward shallower slopes for smaller floe sizes the overall slopes in the cumulative floe size distribution curves from landsat8 images are lower than while those from radarsat 2 are similar to previously reported results in the same region and seasonal period the medea floe size distributions appeared to be sensitive to the passage of storms lead orientations regardless of length correlate slightly better with the peak wave direction than with the mean wave direction their correlation with the geostrophic wind is stronger than with the surface wind the spacing between shorter leads correlates well with the local incoming surface wavelengths obtained from the model peak wave frequency the information derived shows promise for a coordinated multisensor study of storm effects in the arctic marginal ice zone

ice floe distribution in the sea of okhotsk in the period when sea ice extent is advancing 1 ice floe distribution in the sea of okhotsk during a cold air outbreak was investigated by analyzing several thousand of sea ice images obtained by the aircraft observation on 18 february in 2000 the effective floe size became small from 10 m to 2 m within the marginal ice zone miz the scaling properties of floe distribution are demonstrated by a cumulative number frequency which follows a power law scaling with an exponent the value of increased from 1 5 within the internal ice zone to 2 1 within the miz which means that relatively small ice floes dominate in the miz the effective width of the miz estimated by a wave attenuation theory agreed with the observed width suggesting that the flexural stress of waves penetrating into the ice is one of the possible mechanisms which cause the difference in the scaling property

summer transport through the tsushima korea strait transport variations through the korea tsushima strait are examined from two lines of bottom moored acoustic doppler current profilers adcps deployed southwest and northeast of tsushima island in may 1999 almost full depth velocity profiles are measured an optimal interpolation oi scheme is used to interpolate the data spatially and to provide error estimates along each section the strong northeastward current core through the southern section lies approximately in the center of the strait and small southwestward flows occur sporadically near both the korea and japan coasts much of the flow through the northern line occurs near the korea and japan coasts with a weak southwestward mean flow and large variability in the strait center on the leeside of tsushima island the estimated mean transport is 2 9 sverdrups sv through the southern line and 2 5 sv through the northern line the northern line does not extend close to the korea coast where there is significant flow expected errors in the transport estimates at any time are about 0 5 sv rms for each mooring line the gradual transport increase through the summer is carried through the center of the southern line and on the korea side of the strait through the northern line

upper ocean temperature response to hurricane felix as measured by the bermuda testbed mooring hurricane felix passed over the bermuda testbed mooring on 15 august 1995 providing a unique opportunity to observe the response of the upper ocean to a hurricane in the vicinity of bermuda felix was a particularly large hurricane with hurricane force winds over a diameter of about 300 400 km and tropical storm force winds over a diameter of about 650 800 km felix moved northwestward at about 25 km h21 with the eye passing about 65 km southwest of the mooring on 15 august peak winds reached about 135 km h21 at the mooring complementary satellite sea surface temperature maps show that a swath of cooler water by about 3 58 4 08c was left in the wake of felix with the mooring in the center of the wake prior to the passage of felix the mooring site was undergoing strong heating and stratification however this trend was dramatically interrupted by the passage of the hurricane as felix passed the mooring large inertial currents speeds of 100 cm s 21 at 25 m were generated within the upper layer the e folding decay timescale of the inertial currents was about 9 days the mixed layer depth was about 15 m before the arrival of felix and deepened to about 45 m within three days after felix s passage the temperature at 25 m decreased by approximately 3 5 8 4 08c large amplitude temperature oscillations 1 58c near the inertial period inertial pumping effect were set up by the hurricane in the seasonal thermocline resulting in vertical displacements of isotherms of approximately 15 m at 60 70 m comparative scale analyses of the upper ocean responses to hurricane felix and hurricane gloria 1985 indicate that they have several similarities

observations of the response of thermocline currents to a hurricane abstract in september 1985 the eye of hurricane gloria passed within about 100 km of a current meter mooring in the western north atlantic data from this mooring provide a clear view of the vertical structure of the near inertial wake in the main thermocline the response at 159 m was strong 25 cm s 1 amplitude and lasted about 18 days at greater depths the response was weaker and more irregular the phase of the near inertial currents increased with depth consistent with the downward spreading of enemy the total phase change across the thermocline reached about a half cycle seven days after the hurricane s passage indicating a large vertical scale of the response the observations are briefly compared with other time series measurements on the continental margin and with models

observations of strong inertial oscillations after the passage of tropical cyclone ofa one week after tropical cyclone ofa passed near samoa near inertial oscillations of almost 1 m s 1 in amplitude were observed with a shipboard acoustic doppler current profiler adcp the velocity was nearly uniform with depth in the upper 80 m the strongest currents in this layer were found about 300 km from ofa s track farther than expected from previous observations and models below 80 m was a layer 50 100 m thick in which the shear exceeded 0 01 s 1 strong near inertial oscillations with currents over 0 6 m s 1 from 130 to 200 m extended through the shear layer to at least 300 m the limit of the adcp measurements the phase of the oscillations propagated upward consistent with downward propagation of energy a simple slab model driven by an idealized wind field approximately matches the observed amplitude and phase of the oscillations in the surface layer within 150 km of ofa s track but not the stronger current 300 km from the track

advective spreading of storm induced inertial oscillations in a model of the northwest atlantic ocean the spreading of inertial oscillations induced by the passage of hurricane juan 2003 across the gulf stream and the scotian shelf is examined using a regional model of the northwest atlantic ocean it is found that surface intensified inertial oscillations develop at locations remote from the storm track after a period of 5 10 days a diagnostic technique reveals the importance of advection by the background geostrophic flow for explaining this effect the results suggest that advection by mean circulation can play a role in redistributing near inertial energy in the ocean we argue that advective redistribution could have important consequences for understanding diapycnal mixing in the ocean

observed changes in sea ice floe size distribution during early summer in the western weddell sea abstract digital aerial photographs are used to measure the change in floe size distribution over an area of the western weddell sea during the ice station polarstern ispol program the results show a significant increase in the number of small floes and brash ice over a 23 day period from 9 december 2004 to 1 january 2005 this is attributed to a net divergence of the pack ice coupled with ice melt that caused ridges to relax and break into their component parts the net effect is a significant increase in total floe perimeter that is important for lateral melt and primary production near floe edges

size distribution and shape properties of relatively small sea ice floes in the antarctic marginal ice zone in late winter in the marginal sea ice zone miz where relatively small ice floes are dominant the floe size distribution is an important parameter affecting melt processes given the larger cumulative perimeter of multiple small floes compared with a single ice floe of the same area smaller ice floes are therefore subject to increased lateral melt however the available data have been very limited so far analysis of sea ice in the sea of okhotsk revealed that while floe size distribution is basically scale invariant a regime shift occurs at a size of about 40 m in order to extend this preliminary result to the antarctic miz and further examine the controlling factors the first concurrent ice floe size and ice thickness measurements were conducted in the northwestern weddell sea and off wilkes land around 64 s 117 e with a heli borne digital video camera in the late winter of 2006 and 2007 respectively the floe sizes ranged from 2 to 100 m our analysis shows 1 the scale invariance and regime shift are confirmed in both regions 2 the floe size at which regime shift occurs slightly increases from 20 to 40 m with ice thickness consistent with the theory of the flexural failure of sea ice and 3 the aspect ratio is 1 6 1 9 on average close to the previous results based on these results the processes affecting the floe size distribution and the subsequent implications on melt processes are discussed by applying a renormalization group method to interpret the scale invariance in floe size distribution the fractal dimension is related to the fragility of sea ice these results indicate the importance of wave ice interaction in determining the floe size distribution

experimental study on progressive failure process and permeability characteristics of red sandstone under seepage pressure abstract rock masses in underground spaces often experience in situ stress field and seepage field coupling which gives them complex mechanical behavioural and permeability characteristics in this study a high pressure triaxial automated system for rock hptas is employed in triaxial compression testing of red sandstone under different seepage pressures and the variation laws of strength deformation axial strain stiffness and permeability during rock failure are analysed the results show that with changes in the seepage pressure there are also changes in the rock s strength and ability to resist deformation and the stress threshold decreases with an increase in the seepage pressure in addition seepage pressure does not affect the strain stiffness trend but it affects the value throughout the process of stress and strain the permeability curve firstly decreases and then increases rapidly before finally stabilizing and the peak value of the permeability curve lags behind that of the stress strain curve according to the law of permeability evolution during the pre peak progressive failure process a piecewise functional relationship model between permeability and stress is established in this study and theoretical values agree well with experimental results these experimental results can be used as a reference for monitoring and controlling rock stability during geological engineering when a seepage stress coupling action is applied

forced stage response to a moving hurricane abstract the upper ocean s response to three hurricanes norbert 1984 josephine 1984 and gloria 1985 is examined using field observations and a numerical ocean model our goal is to describe the physical processes that determine the structure and amplitude of hurricane driven upper ocean currents all three of these northern hemisphere hurricanes produced a rightward biased response of the mixed layer current and transport this asymmetry arises because the wind stress vector rotates clockwise on the right side of the track and remains nearly parallel with the inertially rotating mixed layer current during most of the hurricane passage the maximum observed mixed layer current varied from 0 8 m s 1 in response to josephine which was a large but comparatively weak hurricane to 1 7 m s 1 in response to gloria which was very large and also intense these cases have been simulated with a three dimensional numerical model that includes a treatment of wind driven vertical mixing within the primitive

the generation of internal waves on the continental shelf by hurricane andrew observed currents temperature and salinity from moored instruments on the louisiana continental slope and shelf reveal multiple baroclinic oscillations during hurricane andrew in august 1992 these measurements are supplemented by numerical models in order to identify possible internal wave generation mechanisms the princeton ocean model is run with realistic topography stratification and wind forcing to extend the observations to mississippi canyon and other areas on the shelf a two layer isopycnal model is used with idealized topography and spatially uniform winds to isolate internal waves generated in and around the canyon the combination of the observations and the results from the numerical models indicates several possible mechanisms for generating long internal waves 1 near inertial internal waves were generated across the slope and shelf by dislocation of the thermocline by the wind stress 2 interaction of inertial flow with topography generated internal waves along the shelf break which bifurcated into landward and seaward propagating phases 3 downwelling along the coast depressed the thermocline after downwelling relaxes an internal wave front propagates as a kelvin wave and 4 poincare waves generated within mississippi canyon propagate seaward while being advected westward over the continental slope these processes interact to produce a three dimensional internal wave field which was only partly captured by the observations

satellite measurements of sea surface cooling during hurricane gloria hurricanes and other strong storms can cause important decreases in sea surface temperature by means of vertical mixing within the upper ocean and by air sea heat exchange here we use satellite derived infrared images of the western north atlantic to study sea surface cooling caused by hurricane gloria 1985 significant regional variations in sea surface cooling are well correlated with hydrographic conditions the greatest cooling up to 5 c occurred in slope waters north of the gulf stream where the seasonal thermocline is shallowest and most compressed moderate cooling up to 3 c occurred in the open sargasso sea where the thermocline is deeper and more diffused little or no cooling occurred in shallow coastal waters bottom depth less than 20 m which were isothermal before the passage of hurricane gloria there is a pronounced right side asymmetry of sea surface cooling with stronger by a factor of 4 and more extensive by a factor of 3 cooling found on the right side of the hurricane track these qualitative results are consistent with the notion that vertical mixing within the upper ocean is the dominant sea surface cooling mechanism of hurricanes

observations of the cold wake of typhoon fanapi 2010 1 several tens of thousands of temperature profiles are used to investigate the thermal evolution of the cold wake of typhoon fanapi 2010 typhoon fanapi formed a cold wake in the western north pacific ocean on 18 september characterized by a mixed layer that was 2 5 c cooler than the surrounding water and extending to 80 m twice as deep as the preexisting mixed layer the initial cold wake became capped after 4 days as a warm thin surface layer formed the thickness of the capped wake defined as the 26 c 27 c layer decreased approaching the background thickness of this layer with an e folding time of 23 days almost twice the e folding lifetime of the sea surface temperature sst cold wake 12 days the wake was advected several hundreds of kilometers from the storm track by a preexisting mesoscale eddy the observations reveal new intricacies of cold wake evolution and demonstrate the challenges of describing the thermal structure of the upper ocean using sea surface information alone

sea ice melting and floe geometry in a simple ice ocean model a coupled sea ice ocean numerical model has been developed that addresses the role of floe geometry during summertime melting the model contains a diagnostic equation for average floe diameter in addition to the usual prognostic equations for ice volume per unit area and ice concentration the partition between melting on the top bottom and lateral side surfaces of floes is examined using time dependent simulations with differing initial average floe diameters the different parameterizations for bottom and lateral melting in the literature are also compared and found to vary significantly the results show that lateral melting is important only for floes with diameters less than o 30 m given atmospheric thermal forcing typical of the central arctic in summer this means that the decrease in ice concentration over the summer is a strong function of floe diameter in keeping with simple geometrical arguments in all cases about 80 of the net thermal energy that enters the ocean through leads goes toward melting ice while the rest warms the ocean

the energy flux from the wind to near inertial motions in the surface mixed layer abstract time series of wind stress computed from long term meteorological buoy data off north america are used to examine the forcing of surface inertial currents by the wind a simple damped slab model of the mixed layer is used to compute h the average flux of energy from the wind to mixed layer inertial currents in a mixed layer of fixed depth h the forcing of mixed layer inertial motions is highly intermittent most of the forcing occurs during the winter months with a few dozen events accounting for typically over half the total energy flux major forcing events are usually associated with translating cold fronts or small lows with scales of about 100 km the larger synoptic scale features have little energy at the inertial frequency and thus result in only weak forcing of inertial currents a strong seasonal signal exists in the inertial forcing at ows p 50 n 145 w 50 m is largest from october to february and is a factor of 12 above the june and july values if seasonally varying

the effect of a storm on the 1992 summer sea ice cover of the beaufort chukchi and east siberian seas for the summer beaufort chukchi and east siberian seas a variety of active and passive microwave satellite data are used to determine the response of the ice edge and interior to a storm specifically the study concentrates on a low pressure system that passed over the region between august 14 and 20 1992 with peak geostrophic winds of about 18 m s 1 through the use of the ers 1 imaging radar and the special sensor microwave imager the ice response is examined at two locations at the ice edge for a nearly stationary location in the chukchi sea and in the ice interior along three swaths in the beaufort chukchi and east siberian seas the ice edge observations show that the storm fractures the large floes into small floes some of which are advected into the adjacent warm water the ice interior observations show that the storm caused an increase in the open water amount and a shift in the floe size distribution toward smaller floes in the ice interior application of the cumulative number distribution n d where n is the number of floes per unit area that are no smaller than some floe diameter d shows that for d 1 km n behaves like d where lies in the range 1 8 2 9 our analysis also shows that this slope is not affected by the storm and is slightly larger near the ice edge

power scaling and seasonal changes of floe areas in the arctic east siberian sea the cumulative number versus floe area distribution of seasonal sea floes from six satellite images of the arctic ocean during the summer breakup and melting is fit by two scale invariant power law scaling regimes for floe areas ranging from 30 to 28 400 000 m2 scaling exponents for larger floe areas range from 0 6 to 1 0 with an average of 0 8 scaling exponents for smaller floe areas range from 0 3 to 0 6 with an average of 0 5 the inflection point between the two scaling regimes ranges from 283 102 to 4850 102 m2 and generally moves from larger to smaller floe areas through the summer melting season the stability of the power scaling results is demonstrated for two of the images by dividing each in half and analyzing each half separately with the result that the scaling exponents and the size of the inflection points are nearly the same for each half as for the whole image we propose that the two scaling regimes and the inflection between them are established during the initial breakup of sea ice solely by the process of fracture the distributions of floe size regimes retain their scaling exponents as the floe pack evolves from larger to smaller floe areas from the initial breakup through the summer season due to grinding crushing fracture and melting the scaling exponents for floe area distribution are in the same range as those reported in previous studies of arctic floes and for the single scaling exponents found for crushed and ground geologic materials including streambed gravel lunar debris and artificially crushed quartz the single scaling exponent found for fault gouge falls below the range for floes possibly because the fracturing and grinding process in fault gouge takes place under high confining pressure a probabilistic model of fragmentation is proposed that generates a single power law scaling distribution of fragment size

characteristics of sea ice floe size distribution in the seasonal ice zone 1 the size distribution of sea ice floes was observed by coordinated landsat imagery and video monitoring conducted from an icebreaker and a helicopter for an area 38 km 26 km in seasonal sea ice in the southern sea of okhotsk in february 2003 the combination of imagery on several scales allowed measurements of ice floes over three orders of magnitude from 1 m to 1 5 km two different regimes were observed floes larger than about 40 m have a power law number density with an exponent of 1 87 in the lower range of earlier results below 40 m the power law exponent is 1 15 the cause of these two different regimes is hypothesized to lie in the effects of swell on floes of different sizes and thicknesses the importance of the floe size distribution for lateral melting is elucidated

experimental investigation on hydraulic fracturing of granite specimens with double flaws based on dic abstract hydraulic fracturing is a crucial technology for shale gas exploitation and enhanced geothermal systems however the fundamental mechanisms of hydraulic fracturing such as the mechanism tensile or shear of cracks physical process of crack initiation propagation and coalescence are not comprehensively understood therefore further direct observations and quantitative investigations are required accordingly an experiment of hydraulic fracturing on double flaw granite specimens was performed the fracturing processes were captured using a high speed camera and a quantitatively study based on digital image correlation dic was achieved dic was proved to be a powerful analysis tool especially for visualising the crack evolution process results show that the crack types in the hydraulic fracturing tests were primarily type i or type ib tensile cracks the process of strain localisation zones slzs revealed the physical process of the hydraulic fracturing slzs initiated at or near pre existing flaw tips before fracturing and then cracks initiated and propagated along the slzs some cracks initiated previously may close with the decrease in fluid pressure after fracturing and evolved into closure cracks the bridging angle was the main factor determining the coalescence patterns and the specimens exhibited direct coalescence category 6 or 7 when 90 slzs were initiated at both inner tips in category 6 while slzs could only be observed at one inner tip in category 7 the ultimate fracturing pressure first decreased then increased as the bridging angle increased

the relation of near inertial motions observed in the mixed layer during the jasin 1978 experiment to the local wind stress and to the quasi geostrophic flow field abstract oscillations with near inertial frequencies were an energetic component of the upper ocean velocity field observed at each of two moorings separated by 44 km during the joint air sea interaction jasin experiment during the late summer of 1978 at each mooring the amplitude of the inertial motion was highest in the mixed layer where it was nearly depth independent previous work pollard and millard 1970 pollard 1980 had found that the amplitude and phase of inertial motion in the mixed layer was related to the local wind stress in this case the loacal winds measured at each mooring were coherent but the time series of mixed layer near inertial motion at one mooring bore little resemblance to that at the other mooring during jasin 1978 the differences in the inertial response at the two moorings coincided with differences in the quasi geostrophic flow field in the vicinity of the two moorings inclusion of the horizontal gradients of the quasi geostrophic flow in model equations prov

effect of typhoon kalmaegi 2014 on northern south china sea explored using muti platform satellite and buoy observations data abstract based on observational data from a buoy mooring array and satellite remote sensing data for sea surface winds temperature and height during the passage of typhoon kalmaegi 2014 a systematic analysis is performed on the atmospheric and oceanic variables of winds sea level air pressure surface air temperature sensible and latent heat fluxes rainfall water temperature salinity and ocean currents kalmaegi passed through the south china sea scs with a mean non dimensional speed of 2 87 typical of a fast moving storm with a predominantly baroclinic oceanic response in addition to some well documented response features such as rightward biased intensifications in sea surface cooling and currents a much deeper mixed layer to the right side of the storm and a strong near inertial oscillation in the thermocline we here identify several new features as follows 1 the current velocity to the right side of the track decays faster than that to the left side 2 on the right side of the track the typhoon induced water temperature anomaly exhibits a three layered cooling warming cooling structure in the vertical with salinity and density anomaly profiles sharing a similar pattern 3 on the left side of the track the whole upper ocean is cooled whereas salinity shows no variation in the uppermost 20 m layer with a negative anomaly for water at depths from 20 to 50 m and a positive anomaly below 50 m the associated mechanisms are discussed in the text 4 the storm induced maximum cooling is not unique to kalmaegi 2014 in fact storms with tracks similar to that of kalmaegi 2014 may induce similar maximum cooling in the northern scs which may be useful in predictions of where such storms would induce the maximum cooling

photogrammetric observations of the lateral melt of sea ice floes melting of the sidewalls of ice floes affects the ice concentration and subsequently the heat and mass balance of the ice cover lateral melt was measured photogrammetrically during marginal ice zone experiments in the greenland sea in june and july 1983 and 1984 a medium format metric camera was used in the second year geometric control was established by surveying a set of targets on each measured floe floe perimeters were measured from sequential photographs and mean lateral melt was estimated to an accuracy of about 6 cm in 1984 melt rates increased from 3 cm d 1 on day 179 to 10 cm d 1 on day 193 the increase precedes the increase of water temperature noted by others on day 191

mechanical behavior of structurally reconstructed irregular columnar jointed rock mass using 3d printing abstract baihetan hydropower station is one the most famous hydroelectric projects in china the columnar jointed rock mass cjrm is widely distributed in this area such as at the dam site and drainage tunnel the rocks surrounding cjrm are usually unstable due to its discontinuity therefore the investigation of mechanical properties of cjrm is essential to designing relevant structures in recent years several previous studies have been conducted to determine the mechanical properties of regular cjrm reconstructed using the mixture of water cement and sand however few studies have been conducted on the irregular cjrms formed in nature because of their structural uniqueness in this study the mechanical properties of irregular cjrms reconstructed using 3d printing technology was investigated and verified through laboratory test first the sampling window method was adopted to obtain the structural characteristics of columnar jointed basalts cjbs after this the mechanical properties i e uniaxial compressive strength ucs uniaxial tensile strength uts peak shear strength residual shear strength failure mode and acoustic emission ae characteristics of the reconstructed and natural cjbs in the laboratory tests were compared based on the similarity constant the results show that the mechanical properties of irregular cjrm reconstructed using 3d printing are consistent with the in situ specimens when considering the similarity constant finally based on a detailed discussion of the reconstructed and original irregular cjrm a new method to accurately reconstruct the structure of irregular cjrms using 3d printing is suggested and verified this method could be used to design irregular cjrms in rock engineering

near inertial motion on the south australian shelf abstract inertial oscillations in current and temperature records collected at two moorings on the south australian continental shelf during february to may 1983 have been examined a strong response to the eastward passage of cold fronts was observed at the well stratified outer shelf site with much of the energy going into first baroclinic mode internal waves surface mixed layer inertial currents attained speeds of 25 30 cm s 1 and were associated with vertical thermocline movements of 10 15 m it is suggested that the inertial currents beneath the mixed layer were the result of pumping of the thermocline due to divergence in the mixed layer inertial motion the phase relationships between the mixed layer currents and thermocline movements were consistent with plane waves propagating in the same direction as the cold fronts typically in the onshore direction the inertial current signal midshelf was generally incoherent with that at the outer shelf 22 km away due to the presence of strong horizontal

satellite observations of asymmetrical physical and biological responses to hurricane earl 1 asymmetrical physical and biological responses to hurricane earl in 2010 are revealed with a combined data set of the moderate resolution imaging spectroradiometer modis ocean color and advanced microwave scanning radiometer eos amsr e sst observations onboard the satellite aqua hurricane earl induced broad sst drops and elevated chlorophyll a concentrations along its track the ocean s physical and biological responses are notably right biased when the hurricane passed along the u s east coast in the ranges within 100 km off the track the sst dropped 1 85 c and 1 23 c on the right and left sides respectively on the other hand the ratios of the chlorophyll a concentration before and after the passage of hurricane earl are 2 04 on the right side and 1 33 on the left in addition to the satellite observed sea surface changes temperature and salinity profiles of an argo float on earl s track show the ocean s physical response occurred mostly within the mixed layer and thermocline in the upper 70 m water column

declassified high resolution visible imagery for arctic sea ice investigations an overview abstract since 2009 subsets of declassified satellite images of arctic sea ice have been released as literal image derived products lidps with one meter resolution for scientific use the collections include imagery acquired over six fixed locations in the arctic basin since 1999 targeted acquisitions over drifting ice parcels from 2009 on provide an added dimension to the lidp archive this mode of acquisition is especially useful for capturing time varying processes during the melt season in this paper we describe the characteristics of lidps the extent of the current archive and highlight their uses for arctic sea ice science at this writing the archive of lidps is still quite limited and thus this paper illustrates the potential utility of the imagery we provide an overview of the retrieval of five sea ice parameters that would benefit significantly from the surface details afforded by the higher resolution lidps they include melt pond coverage open water fraction ridge height floe size and openings and closings two other uses are suggested measurement of lateral melt and the interpretation of radar backscatter the intent is to motivate geophysical uses of the lidp and future acquisitions results here suggest that the effective observations of sea ice parameters and especially their changes require more focused sampling strategies to address specific spatial and temporal sampling needs presently acquisitions of this type of imagery at fixed locations and drifting sites are being continued and lidps are added to the archive as they are released

observed oceanic response over the upper continental slope and outer shelf during hurricane ivan abstract hurricane ivan passed directly over an array of 14 acoustic doppler current profilers deployed along the outer continental shelf and upper slope in the northeastern gulf of mexico currents in excess of 200 cm s 1 were generated during this hurricane shelf currents followed ekman dynamics with overlapping surface and bottom layers during ivan s approach and transitioned to a dominant surface boundary layer as the wind stress peaked slope currents at the onset of ivan were wind driven near the surface but deeper in the water column they were dominated during and after the passage of ivan by subinertial waves with a period of 2 5 days that had several characteristics of topographic rossby waves currents on the slope at 50 m and greater depths commonly exceeded 50 cm s 1 surprisingly the strongest currents were present to the left of the storm track on the shelf while more energetic currents were to the right of the hurricane path on the slope during the forced stage near inertial motion last

horizontal variability of near inertial oscillations associated with the passage of a typhoon 1 surface currents to the east of okinawa island were observed by using hf high frequency ocean radars in august september 1995 during that period a typhoon passed near the observation area and the horizontal variability of near inertial oscillations associated with the typhoon passage was estimated in addition the near inertial amplitudes and horizontal wave number vectors were estimated these estimations showed that the near inertial amplitude was large in the offshore area and small near the coast the maximum near inertial wavelength was estimated to be in the order of 1000 km and the near inertial wave direction was southward and changed to northwestward on 23 august in 1995 a slab model incorporating low frequency currents was used to calculate near inertial currents it was found that the amplitude of calculated near inertial oscillations was also large in the offshore area moreover the phase propagation direction of the near inertial waves was southward and changed to northwestward or westward on 22 august the growth rate obtained from the dispersion relation was large in the offshore area where the near inertial amplitude was large

upper ocean inertial currents forced by a strong storm part i data and comparisons with linear theory abstract a strong isolated october storm generated 0 35 0 7 m s 1 inertia frequency currents in the 40 m deep mixed layer of a 300 km 300 km region of the northeast pacific ocean the authors describe the evolution of these currents and the background flow in which they evolve for nearly a month following the storm instruments included ctd profilers 36 surface drifters an array of 7 moorings and air deployed velocity profilers the authors then test whether the theory of linear internal waves propagating in a homogeneous ocean can explain the observed evolution of the inertial frequency currents the subinertial frequency flow is weak with typical currents of 5 cm s 1 and steady over the period of interest the storm generates inertial frequency currents in and somewhat below the mixed layer with a horizontal scale much larger than the rossby radius of deformation reflecting the large scale and rapid translation speed of the storm this scale is too large for significant linear propagation of the

low frequency current observations in the korea tsushima strait abstract high resolution continuous current measurements made in the korea tsushima strait between may 1999 and march 2000 are used to examine current variations having time periods longer than 2 days twelve bottom mounted acoustic doppler current profilers provide velocity profiles along two sections one section at the strait entrance southwest of tsushima island and the second section at the strait exit northeast of tsushima island additional measurements are provided by single moorings located between korea and tsushima island and just north of cheju island in cheju strait the two sections contain markedly different mean flow regimes a high velocity current core exists at the southwestern section along the western slope of the strait for the entire recording period the flow directly downstream of tsushima island contains large variability and the flow is disrupted to such an extent by the island that a countercurrent commonly exists in the lee of the island the northeastern section is marked b

a report on failures of current meter moorings set east of tsushima island from 1983 to 1987 abstract on the basis of field records we describe failures of current meter moorings deployed in the tsushima strait from 1983 to 1987 in order to avoid future failures of current meter moorings we should communicate frequently with the fishermen s union and deploy the moorings with reserve flotation and acoustic release

upper ocean response to hurricane gilbert the evolving upper ocean response excited by the passage of hurricane gilbert september 14 19 1988 was investigated using current and temperature observations acquired from the deployment of 79 airborne expendable current profilers axcps and 51 airborne expendable bathythermographs from the national oceanic and atmospheric administration wp 3d aircraft in the western gulf of mexico the sea surface temperatures ssts mixed layer depths and bulk richardson numbers were objectively analyzed to examine the spatial variability of the upper ocean response to gilbert net decreases of the ssts of 3o 4oc were observed by the profilers as well as by the airborne infrared thermometer airt along the flight tracks and advanced very high resolution radiometer avhrr imagery the axcps indicated a marked cooling from 29oc to about 25 5oc on september 17 1988 which was about 1 2 inertial periods ip following storm passage this pool of cooler water 3 5 o was located further downstream in the hurricane wake by september 19 2 7 ip following the storm as a result of the near inertial currents in the mixed layer while there was a bias of about 0 6oc and 1 7oc between the in situ and avhrr derived ssts respectively both the avhrr images and the objectively analyzed fields indicated a rightward bias in the upper ocean cooling that extended from the storm track to about 4rmax where rmax the radius of maximum winds is equal to 50 km the larger sst offset of 1 7oc was due to the difference between the time of the avhrr image and the time of the aircraft experiment on september 19 the ssts derived from the avhrr images and the airt also indicated large gradients between the cold wake and the warm eddy in the central gulf of mexico the mixed layer deepened by about 30 35 m on the right side of the track during the storm and 1 2 ip later with little evidence of continued deepening afterward the mixed layer current vectors demonstrate that a strong near inertially rotating current was excited by the passage of gilbert with maxima of about 1 1 4 m s 1 the currents observed during and subsequent to 1 2 ip the storm diverged from the storm track whereas the mixed layer current vectors 2 7 ip after storm passage converged toward the track with relative maxima of 0 8 1 m s 1 this alternating pattern of convergence and divergence of the mixed layer current was associated with the upwelling and downwelling cycles of the baroclinic response considerable current shear existed between the mixed layer and the thermocline currents in the cool wake between the storm track and the 4rmax estimates of the bulk richardson numbers ranged between 0 2 and 1 0 during gilbert and at 1 2 ip which suggests that enhanced current shears were responsible for some of the mixed layer deepening

imaging the active faults with ambient noise passive seismics and its application to characterize the huangzhuang gaoliying fault in beijing area northern china abstract most serious geotechnical problems related to rock engineering are generated by the existence of faults detection of fault especially active faults is the first step to conduct any further in depth studies in faulted rock mass or rock blocks in this paper we investigated the plausibility to image fault zones by passive seismic surveys using recorded ambient noise the test site is in the north suburb of beijing northern china along the south bank of the northwest southeast running wenyuhe river where the nne striking huangzhuang gaoliying fault hgf active in the holocene is crossing in general the results are in good agreement with previous studies using active source seismics conducted in this area along the hgf and existing borehole drillings in the vicinity undoubtedly active source seismic reflection technique is the best technique to image fault in depth with high resolution the drawback is its high cost and the necessity of using explosives a practice usually prohibited in urban settings in contrast passive seismic surveys take the advantage of the ever existing ambient noise source and provide a low cost technique and fast deployment that can locate the fault effectively though the imaging resolution is lower compared to those obtained by active source seismic surveys our passive seismic experiment at the wenyuhe river site demonstrated that this approach is effective especially for those faults with significant normal faulting component and the stratigraphy is significantly different on the two sides crossing the fault line

observations of the summer breakup of an arctic sea ice cover the arctic sea ice cover evolves dramatically through the summer melt season floe size distribution fsd is a critical parameter used to examine this change as the ice cover transitions from large rectilinear plates in spring to an ensemble of discrete rounded floes by midsummer the fsd at a given time impacts the dynamic and thermodynamic behavior of the ice cover focusing on the seasonal marginal ice zone in the beaufort and chukchi seas from may to september 2014 we present qualitative and quantitative results derived from national technical means high resolution imagery and supported by ice mass balance buoy data results indicate that as melt accelerates floe breaking pattern and therefore fsd is heavily influenced by the distribution of melt ponds discrete element model results using morphological conditions derived from analyzed satellite imagery confirmed that breaking occurs along ponds and perpendicular to applied stress

observed near surface flows under all tropical cyclone intensity levels using drifters in the northwestern pacific 1 data from drifters of the surface velocity program and tropical cyclones tcs of the joint typhoon warning center during 1985 2009 were analyzed to demonstrate strong currents under various storm intensities such as category 4 to 5 category 2 to 3 and tropical storm to category 1 tcs in the northwestern pacific current speeds over 2 0 m s 1 are observed under major tcs with the strongest mean currents to the right of the storm track this study provides the characterization of the near surface velocity response to all recorded tcs and agrees roughly with geisler s theory 1970 our observations also verify earlier modeling results of price 1983

study on deformation failure mechanism and support technology of deep soft rock roadway abstract the roadway support has always been a difficult problem in the mining engineering especially in the deep soft rock roadway whether it can provide endurable and effective support directly affects the safety production and sustainable development of the mine in order to solve the supporting issues it is necessary to make the deformation failure mechanism of deep soft rock roadway clear this paper describes a case study of the deformation failure mechanism and support technology of deep roadway with soft rock mass in no 2 mine zone of jinchuan mine that is located in gansu province china based on a detailed field investigation and previous research experience the modes influencing factors laws and mechanisms of deformation failure in the roadway are summarized then the primary combined supporting scheme double layer bolt mesh shotcrete and u shaped steel is evaluated through numerical simulation calculation and onsite experiments to make up for the shortcomings of the primary support an improved combined supporting scheme double layer long bolt mesh shotcrete and cfst concrete filled steel tube is proposed the results of numerical simulation field monitoring and economic analysis show that the new support can control the deformation of the roadway effectively and has a high cost performance finally several suggestions for supporting in deep soft rock roadway are put forward aiming at serve as a reference for other engineering

an application of csamt for detecting weak geological structures near the deeply buried long tunnel of the shijiazhuang taiyuan passenger railway line in the taihang mountains abstract the shijiazhuang taiyuan shitai high speed railway line is designed to cross the taihang mountains the line will include the construction of a 27 85 km long tunnel with a maximum depth of 450 m the taihang mountain tunnel is the key to the successful construction of the railway the geological structure of the tunnel is highly complex and the lithology changes dramatically throughout fault zones karst and groundwater ingress are the main geological engineering problems for the tunnel construction however conventional geophysical methods are not effective for detecting these geological structures in a region with such a complex terrain therefore the controlled source audio frequency magnetotellurics csamt method was used to effectively characterize the resistivity distribution of the underground rock this technique is highly sensitive to low resistivity geological structures such as fault zones and it is effective for studying the geological engineering conditions of the tunnel various corrections designed denoising and inversion methods are used in csamt data processing to obtain the resistivity profile of the entire tunnel based on the resistivity results and existing core information the underground lithological distribution is inferred the location of the fault zone is determined and the distribution of dangerous geological bodies is delineated the interpretation of the csamt results is verified by boreholes and related geological information these results are important for understanding the subsurface geological engineering conditions and have provided stability safety and cost evaluation support for the construction of a long deeply buried tunnel in taihang mountains

mechanism of deep cracks in the left bank slope of jinping first stage hydropower station abstract the proposed jinping first stage hydropower station is located on the middle reach of the yalongjiang river sichuan province pr china it consists of a double curvature arch dam with a maximum height of 305 m which will be the highest in the world cracks are well developed in the left bank slope of the pusiluogou the dam site of jinping first stage hydropower station some cracks are even developed at the horizontal distance into rock face in this paper the term horizontal depth was used to describe the horizontal distance into face of the slope beyond 200 m and these cracks are here referred to as deep cracks the distribution of these deep cracks is far beyond people s experiences in common unloading zones so the mechanism of the deep cracks is put forward as a new subject since these cracks are significant for the stability of the slope their mechanism becomes one of the key engineering geology problems a comprehensive study is made in this paper on the distribution characteristics of the cracks as well as their deformation features the factors that influence their distribution and deformation feature are also analyzed by means of geology mechanics and numerical simulation an important conclusion is consequently reached that deep cracks occurred as a result of release of high ground stress including gravitational stress and tectonic stress the formation of the deep cracks in the slope is a result of unloading process under favorable geology conditions fast crust uplift and quick river cutting and high tectonic stress are indispensable regional geological condition steep and high geometry condition provides favorable geometry condition hard at the lower part and soft at the upper part of the slope offers suitable rock combination condition and back facing bending planes and consequent discontinuities supply suitable structure of the slope

response of subsurface waters in the eastern arabian sea to tropical cyclones abstract thermister chain data at different depths for june 1998 cyclone in the arabian sea at a location 69 2 e 15 5 n which is about 60 km to the left of the cyclone track indicates subsurface warming below 60 m and inertial oscillations of temperature with a periodicity of about 2 days the oscillations continued for 15 days even after the cyclone crossed the coast the analysis of the buoy ds1 located at the same position also suggests a stabilized southward flow after about two weeks of the cyclone crossed the coast analysis of the buoy data for may 1999 cyclone in the same region also indicates similar pattern in order to investigate the effect of cyclone ocean interaction and primarily to understand the process for the subsurface warming 3 dimensional princeton ocean model is configured for the eastern part of the arabian sea the model uses high horizontal resolution of about 6 km near the coast and a terrain following sigma coordinate in the vertical with 26 levels the study focuses on surface cooling and temperature rise in the underlying waters and explains its mechanism through upwelling and downwelling respectively the simulations in concurrence with the observations suggest that the occurrence of subsurface warming precedes the surface cooling with a lag of a day as the cyclone advances ds1 the simulations also demonstrate local temperature stratification plays an important role for cooling of the upper ocean and warming of the subsurface waters and extent of warming is directly related to the depth of the thermocline

inertial oscillations on the continental shelf of the gulf of lions observations and theory abstract observations in the gulf of lions northwestern mediterranean sea in summer have shown that gusts of wind lasting a few days generate transient upwellings and inertial motions oscillations at the inertial frequency were observed in current meter data near the shore and at a frequency 10 greater in the temperature data vertical coherences in current meter data show a strong baroclinic mode at frequencies greater than inertial frequency a simple one dimensional two layer transient model suggests that these motions are associated with two different physical processes the first process describes the local response of the ocean to meteorological forcing the second is associated with the propagation of long internal waves generated in the transient phase of the geostrophic adjustment process as suggested by the model the direction of propagation of the internal waves is computed from current and temperature data measured at one point and it is found that the shore is the source zone

new chemical bio optical and physical observations of upper ocean response to the passage of a mesoscale eddy off bermuda a mesoscale eddy advected across the bermuda testbed mooring site over a 30 day period centered on july 14 1995 temperature and current measurements along with biogeochemical measurements were used to characterize the biological response of the upper ocean associated with the introduction of nitrate into the euphotic layer due to the doming of isotherms associated with the eddy complementary shipboard data showed an anomalous water mass which extended from a depth of 50 to 1000 m manifesting as a cold surface expression and warm anomaly at depth although mesoscale eddies are frequently observed in the sargasso sea the present observations are particularly unique because of the high temporal resolution measurements of the new instrumentation deployed on the mooring analyzers that measure nitrate plus nitrite were placed at depths of 80 and 200 m and bio optical sensors were located at depths of 20 35 45 71 and 86 m peak nitrate values of nearly 3 0 mm at 80 m and chlorophyll a values of 1 4 mg m 23 at 71 m were observed as well as a 25 to 30 meter shoaling of the 1 light level depth a doppler shift from the inertial period 22 8 hours to 25 2 hours was observed in several time series records due to the movement of the eddy across the mooring inertial pumping brought cold nutrient rich waters farther into the euphotic zone than would occur solely by isothermal lifting silicic acid was depleted to undetectable levels owing to the growth of diatoms within the eddy the chlorophyll a values associated with the eddy appear to be the largest recorded during the 8 years of the ongoing u s jgofs bermuda atlantic time series study bats program

model studies of near inertial waves in flow over the oregon continental shelf abstract two dimensional primitive equation model studies of wind forced flow over a continental shelf show that under upwelling conditions high levels of near inertial wave energy are found in the interior over the shelf the regions of elevated wave energy with maximum wave amplitudes of around 0 2 m s 1 persist for up to two weeks and have spatial scales of 20 40 m vertically and 5 20 km horizontally relatively high dissipation levels are associated with these concentrations of wave energy when forced with downwelling favorable winds model results show very little subsurface inertial energy on the shelf a comparison of inertial wave propagation using the primitive equation model and a linearized version of the model demonstrates strong dependence on the background flow field the behavior of inertial waves using the linearized model is completely different very little subsurface inertial energy is seen on the shelf in either upwelling or downwelling conditions except where the bottom slope

experimental investigation and failure mechanism analysis for dacite under true triaxial unloading conditions abstract strong unloading damaged zones at both slopes of the dam of a hydropower station in southwest china have been attributed to the stress release to study the deformation and failure mechanism of dacite dam site material under unloading conditions three groups of true triaxial unloading tests were conducted on the rock sample with an initial minimum principal stress 30 5 mpa and initial intermediate principal stresses 20 10 15 and 20 mpa the experimental results indicate that the strain in the direction of 3 is the most sensitive to the unloading of 3 whereas the three principal strains are further suppressed with increasing 2 ductile deformation is a failure precursor of dacite under unloading conditions based on the analysis of the failure mode and acoustic emission monitoring data it has been concluded that the unloading failure of dacite is caused by the initiation propagation and coalescence of microcracks which form localized tension macrocracks the observed anisotropic damage evolution is found to be determined by stiffness degradation and quantified the degree of fracture during the final unloading stage the results indicate that damage is anisotropic under the true triaxial unloading conditions and that the damage 3 is the most sensitive to the unloading stress 3 therefore the deformation or damage in the direction of 3 can be used as a guide in the design of engineering excavation plans

dust and pollution a recipe for enhanced ocean fertilization 1 for fe contained in aeolian dust to act as a micronutrient for oceanic phytoplankton some fraction of it must first be transformed mobilized into a form soluble in ocean water fe solubilization in deliquesced mineral dust aerosols emanating from east asia during the springtime outflow conditions is investigated here with a lagrangian box model of the gas and aqueous phase chemistry the model simulates the scavenging of soluble and reactive gaseous species by mineral dust aerosols chemical reactions of these species and mineral dust ions in deliquesced solution and dissolution of fe iii oxides that occurs as a result of the acid mobilization the calculations indicate that mineral calcite caco3 strongly buffers deliquesced dust aerosols with a ph that remains close to 8 until the amount of acid added to the aerosol solution exceeds caco3 alkalinity so2 pollutant emissions are a potential source of acidity to advecting dust from east asia the model is used to simulate the chemical evolution of dust plumes formed from two contrasting documented gobi desert storms that advected dust to fe limited regions of the north pacific ocean npo these calculations indicate that only plumes with relatively high initial so2 to dust ratios are capable of delivering significant amounts of bioavailable fe to the npo the estimated change in phytoplankton population inferred from the model calculated inputs of bioavailable fe for these two episodes is consistent with the satellite measured chlorophyll a concentrations in the npo model simulations indicate that 1 large dust advection episodes that can export vast amounts of mineral dust to the open ocean should have insignificant dissolved iron fraction dif as the amount of so2 required to acidify such dust plumes is about an order of magnitude higher than what can typically be entrained in the plume during its advection 2 smaller dust plumes will generally have higher difs because they require lower amounts of so2 and even if such small plumes may not cause algae blooms they could still be important sources of dissolved fe to the npo the calculations suggest that future changes in so2 pollutant emissions from east asia either up or down may affect the productivity of the npo

observation of autumn freeze up in the beaufort and chukchi seas using the ers 1 synthetic aperture radar we present observations of the transition in sea ice backscattering signatures from late summer into early winter in the beaufort and chukchi seas during 1991 and 1992 using data from the ers 1 synthetic aperture radar sar we employ both analyzed surface temperature fields and direct observations of near surface temperature from drifting buoys consistent with previous surface based observations backscattering from sea ice surviving at the end of summer increases strongly and rapidly when temperatures fall below freezing for the final time in the autumn apparently because of increased volume scattering from bubbles in the upper part of the ice areally averaged backscattering sometimes overshoots typical winter multiyear ice values by 1 2 db before settling back over a period of approximately a week the backscattering temperature link forms a sufficient basis for an algorithm to estimate retrospectively from time series of sar images the date of freeze up defined here to be the date on which all liquid water in the bubbly upper layer of surviving sea ice freezes and remains frozen for the duration of the ensuing autumn and winter we present a prototype algorithm and use it to estimate freeze up dates in nine lagrangian cells in the beaufort sea during the autumn of 1992 we observe a 12 day spread in freeze up dates between latitudes of approximately 73 n and 82 n with dates in the northernmost cells of august 29 30 and those in the southernmost cells of september 7 two cells at latitudes of 75 n 77 n appear to freeze up earlier than cells further north but present uncertainties limit the significance of this observation

inertial oscillations in the korea strait inertial oscillations io are examined in the korea strait based on measurements from 13 acoustic doppler current profilers covering the time period may 1999 through march 2000 strong io responses to wind stress occur during summer a simple linear model predicts that winter wind stress is expected to generate inertial responses of the same order of magnitude as those in summer however the observed winter io response is much weaker than predicted during summer the currents within the mixed layer and below the mixed layer are of comparable amplitude but in opposite directions the depth at which the currents reverse directions varies throughout the year as the mixed layer deepens from about 40 m during summer to the bottom of the water column in november during winter the velocity structure is more uniform in depth with currents in the same direction throughout the water column one possible explanation for these phenomena is related to the combined effect of the strait boundaries and the strong summer stratification the stratification prevents the wind stress momentum flux from mixing downward below the thermocline and thus allows the development of a bottom current separate from the surface current such a velocity structure is necessary to satisfy the no flow condition through the land boundaries

seasonal and interannual variability in deep ocean particle fluxes at the oceanic flux program ofp bermuda atlantic time series bats site in the western sargasso sea near bermuda abstract since 1978 the oceanic flux program ofp time series sediment traps have measured particle fluxes in the deep sargasso sea near bermuda there is currently a 20 yr flux record at 3200 m depth a 12 yr flux at 1500 m depth and a 9 yr record at 500 m depth strong seasonality is observed in mass flux at all depths with a flux maximum in february march and a smaller maximum in december january there is also significant interannual variability in the flux especially with respect to the presence absence of the december january flux maximum and in the duration of the high flux period in the spring the flux records at the three depths are surprisingly coherent with no statistically significant temporal lag between 500 and 3200 m fluxes at our biweekly sample resolution bulk compositional data indicate an extremely rapid decrease in the flux of organic constituents with depth between 500 and 1500 m and a smaller decrease with depth between 1500 and 3200 m depth in contrast carbonate flux is uniform or increases slightly between 500 and 1500 m possibly reflecting deep secondary calcification by foraminifera the lithogenic flux increases by over 50 between 500 and 3200 m depth indicating strong deep water scavenging repackaging of suspended lithogenic material concurrent with the rapid changes in flux composition there is a marked reduction in the heterogeneity of the sinking particle pool with depth especially within the mesopelagic zone by 3200 m depth the bulk composition of the sinking particle pool is strikingly uniform both seasonally and over variations in mass flux of more than an order of magnitude these ofp results provide strong indirect evidence for the intensity of reprocessing of the particle pool by resident zooplankton within mesopelagic and bathypelagic waters the rapid loss of organic components the marked reduction in the heterogeneity of the bulk composition of the flux and the increase in terrigenous fluxes with depth are most consistent with a model of rapid particle turnover and material scavenging from the suspended pool during new particle formation we suggest that much of the deep mass flux is generated in situ by deep dwelling zooplankton and that mass flux as well as scavenging of suspended materials from the deep water column varies in proportion to changes in grazer activity labile very rapidly sinking aggregates e g salp fecal material arriving in the bathypelagic zone within days of their upper ocean production may act to stimulate zooplankton grazing rates and increase large particle production and deep mass flux days to weeks in advance of the arrival of bulk of surface produced material this process could reconcile mean particle sinking rate estimates with the phase coherence observed between upper and deep ocean mass fluxes

upper ocean response to hurricane gonzalo 2014 salinity effects revealed by targeted and sustained underwater glider observations during october 2014 hurricane gonzalo traveled within 85 km from the location of an underwater glider situated north of puerto rico observations collected before during and after the passage of this hurricane were analyzed to improve our understanding of the upper ocean response to hurricane winds the main finding in this study is that salinity potentially played an important role on changes observed in the upper ocean a near surface barrier layer likely suppressed the hurricane induced upper ocean cooling leading to smaller than expected temperature changes poststorm observations also revealed a partial recovery of the ocean to prestorm conditions 11 days after the hurricane comparison with a coupled ocean atmosphere hurricane model indicates that model observations discrepancies are largely linked to salinity effects described results presented in this study emphasize the value of underwater glider observations for improving our knowledge of how the ocean responds to tropical cyclone winds and for tropical cyclone intensification studies and forecasts

determining the applicability of the barotropic approximation to the mean seasonal flow through the tsushima korean strait using variational assimilation abstract variational assimilation is used to combine velocity and sea surface height anomaly ssha measurements with a system of dynamics to estimate the seasonal flow through the tsushima korean strait for the summer autumn and winter seasons of 1999 2000 the velocity measurements are from two lines of moored acoustic doppler current profilers adcps spanning the tsushima korean strait just north and south of tsushima island and the ssha measurements are from the topex altimeter the dynamics are the linear time independent shallow water equations and are forced by winds from the navy global ocean and atmospheric prediction system a weighted least squares technique is used to determine the seasonal flow fields that simultaneously minimize the weighted residuals of the two data sets and the system of dynamics the weights are based on expected errors allowing the assimilation system to put more emphasis on the components of data and dynamics that are known more accurately earlier studies show that the flow through the tsushima strait is barotropic throughout most of the year the region just offshore of the southeast coast of south korea however has been identified as being subject to strong baroclinic processes during autumn in an attempt to verify this observation best estimates of the seasonal flow fields are computed by assimilating the two data sets with both a single layered barotropic system of equations and a 2 5 layered baroclinic system of equations the minimized residuals of the barotropic system of equations reveal that the solutions satisfy these equations within expected errors throughout most of the domain just offshore of the southeast coast of south korea however the barotropic momentum equation residuals exceed 3 times the expected error during autumn therefore implying that the barotropic approximation is not valid at this location the 2 5 layered baroclinic momentum equation residuals within this region are smaller than the barotropic residuals suggesting the existence of baroclinic processes

free surface effects on the near inertial ocean current response to a hurricane abstract during the passage of hurricane frederic in 1979 four ocean current meter arrays in water depths of 100 950 m detected both a baroclinic and a depth independent response in the near inertial frequency band although the oceanic response was predominately baroclinic the hurricane excited a depth independent component of 5 11 cm s 1 the origin and role of the depth independent component of velocity is investigated using a linear analytical model and numerical simulations from a 17 level primitive equation model with a free surface both models are forced with an idealized wind stress pattern based on the observed storm parameters in hurricane frederic in an analytical model the green s function k0 is convolved with the wind stress curl to predict a sea surface depression of approximately 20 cm from the equilibrium position the near inertial velocities are simulated by convolving the slope of the sea surface depression with a second green s function the barotropic current velocities rotate

an examination of the thermodynamic impacts of western north pacific tropical cyclones on their tropical tropospheric environment abstractthe present study examines the tropospheric thermodynamic anomalies induced by western north pacific tropical cyclone tc passage using storm relative composites negative moist static energy mse anomalies containing embedded westward propagating anomalies generally occur only following larger tcs for two months following tc passage in a region extending from the domain center to 3000 km to its west larger tcs force negative mse anomalies likely because of feedbacks from stronger broader tc induced negative sea surface temperature sst anomalies and the excitation of tc induced rossby waves to the southeast of the tc the negative mse anomalies are composed of lower and midtropospheric negative latent energy anomalies with smaller contributions from boundary layer and upper tropospheric negative sensible heat anomalies the lower and midtropospheric negative mse anomalies are forced by the tc whereas the upper tropospheric negative mse anomalies are forced by the madden julian oscillatio

the role of shortwave radiation in the summer decay of a sea ice cover heat balance models of ice leads and the underlying water column were used to investigate the role of shortwave radiation in the summer decay of a sea ice cover because of the potential importance of positive feedback between decreasing ice concentration and increasing solar input to the ocean particular emphasis was given to the treatment of heat transfer and lateral melting in leads the rate of heat loss to floe edges was calculated from lead temperatures using an empirical boundary layer parameterization coefficients for this parameterization were obtained from field measurements in the dynamically active ice cover of the greenland sea during the 1984 marginal ice zone experiment and in the static ice of mould bay northwest territories field coefficients were found to be considerably larger than those previously obtained in the laboratory suggesting that heat transfer rates near floe edges were controlled more by winds and currents than by local density differences model studies of individual leads indicate that heat losses to the atmosphere cause lateral melt rates to asymptotically approach a constant value as lead size increases thus although very wide leads transmit considerable energy to the underlying ocean they have relatively little effect on lateral melting other results provide information on the relative importance of horizontal heat transfer rates ice thickness floe perimeter atmospheric forcing and oceanic heat flux in general the calculations indicate that much of the shortwave radiation entering the ocean is absorbed below the ice where it contributes to bottom ablation rather than lateral melting this suggests that previous work has seriously overestimated the magnitude of the feedback between ice concentration and incident shortwave radiation

observations and analyses of upper ocean responses to tropical storms and hurricanes in the vicinity of bermuda 1 a circular region within a radius of 400 km of bermuda has been struck by 188 tropical storms or hurricanes from 1851 through 2005 and by 20 since 1995 here we describe new direct and remote sensing observations and analyses of recent events near the bermuda testbed mooring including hurricane fabian 2003 tropical storm harvey 2005 and hurricane nate 2005 the most impressive upper ocean response of the recent events was produced by hurricane fabian when sst cooling exceeded 3 5 c vertical mixing occurred to a depth of greater than 130 m and upper ocean currents reached 100 cm s 1 fabian also triggered an ocean color event visible in seawifs satellite images related implications include improved estimates of the roles of tropical cyclones in driving meridional overturning circulation moc and testing of hypotheses concerning warming of the tropical oceans which could cause more intense tropical storms and hurricanes

uncertainty propagation in coupled atmosphere wave ocean prediction system a study of hurricane earl 2010 abstractthis study focuses on understanding the evolution of hurricane earl 2010 with respect to random perturbations in the storm s initial strength size and asymmetry in wind distribution we

the ocean boundary layer below hurricane dennis abstract three neutrally buoyant floats were air deployed ahead of hurricane dennis on 28 august 1999 these floats were designed to accurately follow three dimensional water trajectories and measure pressure i e their own depth and temperature the hurricane eye passed between two of the floats both measured the properties of the ocean boundary layer beneath sustained 30 m s 1 winds the floats repeatedly moved through a mixed layer 30 70 m deep at average vertical speeds of 0 03 0 06 m s 1 the speed was roughly proportional to the friction velocity mixed layer temperature cooled about 2 8 and 0 75 c at the floats on the east and west sides of the northward going storm respectively much of the cooling occurred before the eye passage the remaining terms in the horizontally averaged mixed layer heat budget the vertical velocity temperature covariance and the lagrangian heating rate were computed from the float data surface heat fluxes accounted for only a small part of the cooling most of th

numerical study of the storm induced circulation on the scotian shelf during hurricane juan using a nested grid ocean model a nested grid ocean circulation modelling system is used to assess the upper ocean response of the scotian shelf and adjacent slope to hurricane juan in september 2003 the nested grid system consists of a fine grid inner model covering the scotian shelf slope and a coarse grid outer model covering the northwest atlantic ocean the model calculated upper ocean response to hurricane juan is characterized by large divergent surface currents forced by the local wind forcing under the storm and intense near inertial currents in the wake of the storm the sea surface temperature sst cooling produced by the model is biased to the right of the storm track and agrees well with a satellite derived analysis over the deep water off the scotian shelf some of the near inertial energy input by the storm is advected eastward by the gulf stream away from the storm track the hurricane also generates shelf waves that propagate equatorward with the coastline on their right in comparison with the outer model results the inner model captures more meso scale structures greater sst cooling and stronger near inertial currents in the study region

the sensitivity of upper ocean structure to time varying wind direction observations and models show that sudden changes in the magnitude of the wind stress which occur within a time interval of one half inertial period are most effective in increasing surface current speeds and mixing the upper layers of the ocean the purpose of the present study is to quantify the effects of concurrent time dependent wind direction the mellor yamada level 2 1 2 turbulence closure model is used a series of model runs was executed in order to determine the relative sensitivity of mixed layer depth and sea surface temperature to wind speed as compared with the rate of change of wind direction the results indicate that the accuracy and time resolution of wind direction should be given special consideration in the design and interpretation of field experiments which will be used for testing prognostic mixed layer models

response of upper ocean currents to typhoon fanapi the response of upper ocean currents to typhoon fanapi in fall 2010 was studied using an extensive air deployed drifter array separation of the observations into near inertial and sub inertial motions quantified the importance of strong advection by the sub inertial circulation for the evolution of the cold wake formed by typhoon fanapi the near inertial currents generated during the storm showed the expected rightward bias with peak magnitudes of up to 0 6 m s and an e folding time of about 4 days for the strong currents within the cold wake the shear of the near inertial currents is crucial for the storm induced cooling and deepening of the mixed layer and such instabilities were here directly observed across the base of the mixed layer in typhoon fanapi s cold wake during the recovery the diurnal cycle a dominant process for the wake warming was found to be noticeably reduced when the near inertial motions were strongest

the effect of possible taylor columns on the summer ice retreat in the chukchi sea the chukchi sea topography consists of a broad flat 50 m deep plain with two prominent shoals herald and hanna which have horizontal dimensions of about 100 km and rise to depths of about 30 m herald shoal in particular is a prominent isolated seamount which because of the warm water flux in summer through bering strait has a warm 0 1 m s 1 flow incident upon it examination of active and passive microwave imagery of the region for 1992 1994 shows that as the general ice cover recedes the ice remains preferentially over herald shoal for 3 4 weeks after the surrounding ice has melted a scale analysis suggests that the cause of the ice persistence is the formation of a taylor column over the shoal which traps cold water and ice above it a similar trapping of ice occurs over hanna shoal and on its eastern slope but the response is complicated by a very different topography and the northward flow down barrow canyon

the seasonal evolution of sea ice floe size distribution the arctic sea ice cover undergoes large changes over an annual cycle in winter and spring the ice cover consists of large snow covered plate like ice floes with very little open water by the end of summer the snow cover is gone and the large floes have broken into a complex mosaic of smaller rounded floes surrounded by a lace of open water this evolution strongly affects the distribution and fate of the solar radiation deposited in the ice ocean system and consequently the heat budget of the ice cover in particular increased floe perimeter can result in enhanced lateral melting we attempt to quantify the floe evolution process through the concept of a floe size distribution that is modified by lateral melting and floe breaking a time series of aerial photographic surveys made during the sheba field experiment is analyzed to determine evolution of the floe size distribution from spring through summer based on earlier studies we assume the floe size cumulative distribution could be represented by a power law d where d is the floe diameter the exponent as well as the number density of floes ntot are estimated from measurements of total ice area and perimeter as summer progressed there was an increase in as the size distribution shifted toward smaller floes and the number of floes increased lateral melting causes the distribution to deviate from a power law for small floe sizes

highly resolved observations and simulations of the ocean response to a hurricane 1 an autonomous profiling float called em apex was developed to provide a quantitative and comprehensive description of the ocean side of hurricane ocean interaction em apex measures temperature salinity and pressure to ctd quality and relative horizontal velocity with an electric field sensor three prototype floats were air deployed into the upper ocean ahead of hurricane frances 2004 all worked properly and returned a highly resolved description of the upper ocean response to a category 4 hurricane at a float launched 55 km to the right of the track the hurricane generated large amplitude inertially rotating velocity in the upper 120 m of the water column coincident with the hurricane passage there was intense vertical mixing that cooled the near surface layer by about 2 2 c we find consistent model simulations of this event provided the wind stress is computed from the observed winds using a high wind speed saturated drag coefficient

automatic identification and characterization of discontinuities in rock masses from 3d point clouds abstract the routine application of remote surveying techniques which can quickly acquire 3d digital data with high resolution in particular digital photogrammetry light detection and ranging lidar and unmanned aerial vehicle uav for rock mass characterization has rapidly grown over the past decade in this paper a new method for automatic identification and interpretation of rock mass discontinuities clustering of discontinuity sets and characterization of discontinuity orientation persistence and spacing using 3d point clouds is presented the proposed method is based on a four stage procedure consisting of 1 normal vector calculation using the iterative reweighted plane fitting irpf method 2 discontinuity sets clustering by fast search and find of density peaks cfsfdp algorithm and fisher s k value iterative calculation to eliminate noise points 3 discontinuity segmentation using density ratio based method and discontinuity plane fitting using the random sample consensus ransac algorithm 4 persistence and spacing calculation using the theory of analytic geometry the method is applied to two case studies i e rock slopes and compared with the results from previous studies and from manual survey it is concluded that the proposed method is reliable and yields a great accuracy for automatic identification of discontinuities in rock masses

a reassessment of the integrated impact of tropical cyclones on surface chlorophyll in the western subtropical north atlantic the impact of tropical cyclones on surface chlorophyll concentration is assessed in the western subtropical north atlantic ocean during 1998 2011 previous studies in this area focused on individual cyclones and gave mixed results regarding the importance of tropical cyclone induced mixing for changes in surface chlorophyll using a more integrated and comprehensive approach that includes quantification of cyclone induced changes in mixed layer depth here it is shown that accumulated cyclone energy explains 22 of the interannual variability in seasonally averaged june november chlorophyll concentration in the western subtropical north atlantic after removing the influence of the north atlantic oscillation nao the variance explained by tropical cyclones is thus about 70 of that explained by the nao which has well known impacts in this region it is therefore likely that tropical cyclones contribute significantly to interannual variations of primary productivity in the western subtropical north atlantic during the hurricane season

large eddy simulations of upper ocean response to a midlatitude storm and comparison with observations abstract a large eddy simulation les model is used to investigate an upper ocean response to a fall storm in the open ocean of the north pacific ocean the storm is characterized by rapid increases in wind speed and surface heat loss but a relatively steady wave field the les model shows that surface convergence zones or windrows organize into line patterns aligned with the wind direction evolving from nearly parallel lines to irregular structures featuring y junctions as the wind speed increases the downwelling to upwelling velocity ratio ranges between 1 2 and 1 6 indicating a moderate level of asymmetry between the downwelling and upwelling plumes in langmuir circulation during the storm the turbulent langmuir number lat increases from 0 2 to 0 5 while the vertical turbulence intensity w2 decreases from 1 4 to 0 7 u 2 where u is the friction velocity the order of turbulence intensities in three directions switches from crosswind vertical downwind directions to downwind crosswind ver