the 3d oceanic mixed layer response to hurricane gilbert upper ocean heat and mass budgets are examined from three snapshots of data acquired during and after the passage of hurricane gilbert in the western gulf of mexico measurements prior to storm passage indicated a warm core eddy in the region with velocities of o 1 m s21 based upon conservation of heat and mass the threedimensional mixed layer processes are quantified from the data during and subsequent to hurricane passage horizontal advection due to geostrophic velocities is significant in the eddy regime suggesting that prestorm oceanic variability is important when background flows have the same magnitude as the mixed layer current response storm induced near inertial currents lead to large vertical advection magnitudes as they diverge from and converge toward the storm track surface fluxes estimated by reducing flight level winds to 10 m indicate a maximum wind stress of 4 2 n m22 and a heat flux of 1200 w m 22 in the directly forced region the upward heat flux after the passage of the storm has a maximum of 200 w m22 corresponding to a less than 7 m s21 wind speed entrainment mixing across the mixed layer base is estimated using three bulk entrainment closure schemes that differ in their physical basis of parameterization entrainment remains the dominant mechanism in controlling the heat and mass budgets irrespective of the scheme depending on the magnitudes of friction velocity surface fluxes and or shear across the mixed layer base the pattern and location of maximum entrainment rates differ in the directly forced region while the general area of maximum entrainment is in the right rear quadrant of the storm shear induced entrainment scheme predicts a narrow region of cooling compared to the the stressinduced mixing scheme and observed sst decreases after the storm passage the maximum contribution to the mixed layer dynamics is associated with shear induced entrainment mixing forced by near inertial motions up to the third day as indicated by bulk richardson numbers that remained below criticality thus entrainment based on a combination of surface fluxes friction velocity and shear across the entrainment zone may be more relevant for three dimensional ocean response studies

comparison of speleothem fabrics and microstratigraphic stacking patterns in calcite stalagmites as indicators of paleoenvironmental change abstract in the necessary task of obtaining high resolution paleoclimate series from speleothems the characterization of their internal microstratigraphy is a useful tool for a improving geochronology and b reaching a more complete knowledge of the speleothem formation and evolution through time and thus obtaining additional paleoenvironmental information however the development of standardized methodologies for microstratigraphic characterization is a pending task in this paper two different approaches allow construction of microstratigraphic logs for three stalagmites retrieved from two different caves the logs correspond to vertical variations in speleothem fabrics and in microstratigraphic stacking patterns the fabrics logs essentially provide information about the drip rate sometimes used as a precipitation proxy and the regularity or irregularity of each drip in the short term the microstratigraphic stacking patterns logs can be interpreted to obtain information about the changes in drip rates in the mid and long term the results show a broad correlation between both kinds of logs that supports their validity as paleoenvironmental proxies fabrics formed under relatively constant and regular drips columnar compact open and elongated usually constitute aggradational or progradational microstratigraphic stacking patterns on the other hand retractional stacking patterns are usually related with fabrics precipitated under more irregular drips dendritic and columnar microcrystalline however this relation is not rigid and the information obtained from the logs is not equivalent but complementary the combination of both logs allows reconstruction of the hydrological history for each drip site as all the obtained information derives directly from the drip conditions drip effects result to be very important and can in some cases overwhelm the paleoclimate information recorded in each stalagmite

near inertial ocean current response to hurricane frederic abstract hurricane frederic passed with 80 to 130 km of the u s naval oceanographic office current meter arrays in water depths ranging from 100 to 470 m near the desoto canyon region and within 150 km of an ocean thermal energy conversion otec mooring in 1050 m of water excitation of near inertial waves by the moving hurricane was observed throughout the water column along the canyon walls and at the otec site the frequencies of the waves were blue shifted between 1 to 6 above the local inertial frequency the horizontal wavelength of 250 km is consistent with an energetic first baroclinic mode response but is considerably below the linear theory prediction of 550 km the inferred vertical wavelengths of the immediate response exceeded 1000 m along the northern and eastern sides of the canyon since the currents throughout the water column increased within hours of the hurricane passage later the vertical wavelengths were about equal to the water depth the vertical group velocities associated

lower continental slope cyclonic eddies in the central gulf of mexico current meters an inverted echo sounder hydrography drifters and satellite imagery are used to characterize relatively small 100 to 150 km diameter cold cyclonic eddies in the central basin and on the lower louisiana slope of the gulf of mexico these cyclones are shown to be long lived 6 months or more have limited movements when compared with loop current anticyclones and be fairly vigorous with upper layer currents of 30 50 cm s 1 they usually have only small temperature differences with surrounding water masses in the upper 50 to 100 m of the water column and are therefore not readily apparent in satellite thermal imagery the largest isotherm displacements occur over depths of 200 800 m in one case a cyclone was traced from the deep basin near 92 w to the northern slope as a major anticyclone propagated southwestward through the gulf the presence of cyclones and anticyclones on the louisiana slope is consistent with observed current meter measurements in the upper half of the water column that have long several months periods and approximately equal variances in the cross slope and along slope directions

internal inertial waves in a surgasso sea front abstract this work examines the presence of internal inertial waves in a front in the north atlantic subtropical convergence zone results of doppler shear profiler and towed thermistor chain surveys are displayed to document the position and magnitude of the front objective maps of the total measured velocity are computed and subtracted from the observed velocity fields the remaining wave signal is processed to yield horizontal towed and vertical dropped kinetic energy spectra across the front from these rotary spectra are also computed along the line of tow and in the vertical to determine the horizontal and vertical anisotropy it is found that several nearly monochromatic waves are propagating northward and southward from the front with horizontal length scales of 32 50 km it was also discovered that the region of anticyclonic frontal vorticity exhibits an excess of downgoing energy at the longest vertical wavelength thus sampled 50 m while the region of cyclonic vorticity possesses more

erratum to reply to the comment on physical and stable isotope evidence for formation of secondary calcite and silica in the unsaturated zone yucca mountain nevada by y v dublyansky s e smirnov and g p palyanova applied geochemistry 19 2004 1879 1889

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

frequency of ring separations from the loop current in the gulf of mexico a revised estimate the most energetic events in the circulation of the gulf of mexico are the separation of large anticyclonic rings from the loop current building on previous work the authors examine all the apparent rings since july 1973 this new dataset includes the satellite altimetry since 1992 providing a set of 34 consecutive ring formations the primary advantage of altimetry is that the data remain available in the summer one finding is that the ambiguity of whether or not a ring has separated is reduced but not eliminated the uncertainty with which separation events can be specified remains approximately 4 weeks even with nearly continuous data primary peaks in the distribution of separation intervals are found at 6 and 11 months with a smaller peak at 9 months if the spectrum is smoothed heavily enough a peak in the distribution can be formed nearer 12 months but this near annual peak is a result more of the smoothing than of the data

mean and near inertial ocean current response to hurricane gilbert abstract the three dimensional hurricane induced ocean response is determined from velocity and temperature profiles acquired in the western gulf of mexico between 14 and 19 september 1988 during the passage of hurricane gilbert the asymmetric wind structure of gilbert indicated a wind stress of 4 2 n m 2 at a radius of maximum winds rmax of 60 km using observed temperature profiles and climatological temperature salinity relationships the background and storm induced geostrophic currents re 750 m were 0 1 m s 1 and 0 2 m s 1 respectively a loop current warm core ring lcwcr was also located to the right of the storm track at 4 5 rmax where anticyclonically rotating near surface and 100 m currents decreased from 0 9 m s 1 to 0 6 m s 1 at depth the relative vorticity in the lcwcr was shifted below the local coriolis parameter by about 6 in a storm based coordinate system alongtrack residual velocity profiles from 0 to 4 rmax were fit to a dynamical model by least squares to isolate the near

the wake of hurricane allen in the western gulf of mexico abstract in august 1980 hurricane allen passed over a moored array of instruments recording current temperature and conductivity in the western gulf of mexico an alongshore surge occurred during the storm passage with the horizontal current speed reaching 91 cm s 1 in the thermocline 200 m and diminishing to 15 cm s 1 32 m above the bottom 732 m a wake of near inertial frequency internal waves commenced after the storm passed the array the alongshore current oscillation reached a maximum range of 50 cm s 1 within 3 days and decayed thereafter with a time scale of about 5 days the current oscillations were clockwise polarized and slightly elliptical with a period of 22 23 h or about 85 of the local inertial period near uniform upwelling of 20 m occurred in the thermocline region 200 300 m during the most intense part of the wake depth leading phases of the horizontal current and temperature oscillations indicated downward radiation of wake energy the wake oscillations were highly coheren

near inertial internal waves observed on the outer shelf in the middle atlantic bight in the wake of hurricane belle abstract on 10 august 1976 hurricane belle passed rapidly over the highly stratified shelf of the new york bight records from aanderaa current meter moorings show that the response to the hurricane depended strongly on bathymetry at deeper stations 70 m depth intense first mode internal near inertial oscillations were generated at frequencies 1 less than the local inertial frequency at shallower stations 50 m depth only weak heavily damped second mode oscillations were observed in the current records with no corresponding inertial signals in temperature in the hudson shelf valley inertial motion occurred only near the surface this was probably due to topographic effects the divergence and curl of the wind stress contributed equally to the forcing the response at the deeper stations is consistent with geisler s 1970 theory for the open ocean in which a hurricane leaves a wake of internal inertial oscillations if it travels faster than the internal phase speed and if its horizontal s

climatology of ocean features in the gulf of mexico using satellite remote sensing data a climatology of various ocean features in the gulf of mexico gom was developed using the combination of satellite remote sensing and in situ data that spanned periods as long as 32 years twelve separate statistics were created some of which described characteristics of the loop current while others are involved with warm core rings that separate from the loop current and cold core rings these statistics examined the frequency with which the loop current was found in the gom the orientation of the loop current the frequency of intrusion of loop current water onto the west florida shelf and into the gom common water region ring separation period from the loop current ring dissipation ring speed ring path frequency of ring water in the western gom and the frequency of warm and cold core rings wcrs and ccrs respectively in the gom the results indicate that ccrs were principally responsible for mass and heat redistribution in the eastern gom egom and wcrs are responsible for mass and heat redistribution in the western gom wgom the average period for wcr separation from the loop current was 11 months and the range from 5 to 19 months wcrs moved through the wgom most often using the central path i e their trajectory was found between 24 and 26 n latitude and they decreased to about 55 of their initial size when they reach the western wall of the gom ccrs were most often found in the egom and their frequency of occurrence in the egom surpassed that of wcrs anywhere in the gom

on the response of the ocean to a moving storm parameters and scales abstract this paper has two purposes one is to present a new and efficient multilevel numerical model for calculating the response of the ocean to a moving storm the second is to show how on a time scale of a few inertial periods following the arrival of the storm the maximum horizontal and vertical velocities found in the wake can be calculated using a linear ekman model and a knowledge of that part of the change in the depth of the wind mixed layer due to entrainment this is demonstrated over a range of experiments with the multilevel numerical model these integrate the full nonlinear equations of motion with realistic ocean stratification and involve substantial entrainment of water into the wind mixed layer it is also shown that on this time scale the horizontal currents are confined near the surface but that the vertical velocity field extends throughout the depth of the ocean it is shown in appendix b that the wind forcing need only be large or fast for the forced response not to feel t

energy flux from traveling hurricanes to the oceanic internal wave field abstract the generation of long interval waves by traveling hurricanes on an f plane is studied within the context of linear theory the emphasis of the present work is on the interval wave power that is the fraction of the energy input from the hurricane that is absorbed by the internal wave field in the ocean particular attention is paid to the dependence of the interval wave power on the hurricane speed the oceanic stratification and the coriolis parameter a formula for the wave power expressed in terms of the wind forcing spectrum is derived the wave power can be divided in two parts one part generated by the divergence of the wind stress and one part generated by the curl of the wind stress the latter part which is dominating for hurricanes is always decreased when the strength of the stratification is increased while the former part may either increase or decrease depending on the speed of the hurricane it is shown that for a specified stratification and a fixed latitude the wave po

on the behavior of internal waves in the wakes of storms abstract the rossby adjustment process in the wake of a storm is studied with a view to finding within the context of linear theory how wave dispersion in both the vertical and meridional directions spreads energy which is initially confined entirely to the mixed layer comparisons are made between three cases 1 a periodic storm on the f plane where dispersion is purely vertical 2 a bounded storm on the f plane and 3 a bounded storm centered 2700 km from the equator on an equatorial beta plane particular attention is paid to the initial rate of loss of energy from the mixed layer and some simple formulas which work very well in the cases studied are derived these show that the rate of loss goes up when the mixed layer depth is increased and also that the rate scales as the square of the wavenumber values of the rates are sufficient to provide a major source of energy for internal waves below the mixed layer the often observed tendency for phase lines to propagate upward is found in all case

inertial wave dynamics in the north atlantic subtropical zone doppler current profiler observations of an inertial wave packet are presented from a region where a cold core ring impinges on a front in this intense current a drogue is deployed to mark one region of the fluid as the drogue is advected by the current the ship follows it zigzagging across the drogue s trajectory along this ship track vertical rotary velocity spectra indicate the presence of a downgoing intertial wave with a vertical wavelength which slowly changes from 50 to 100 m as time progresses the wave s intrinsic frequency was measured for the first time ever a horizontally synoptic data set is obtained at the drogue depth by correcting for frontal advection and the temporal rotation of the wave velocity examination of these synoptic data indicates the presence of a southgoing near inertial wave with horizontal wavelength 20 km the wave is confined to a 25 km region supplementary ray tracing calculations through objective maps of the ring flow field indicate that the wave is strongly influenced by doppler shifting this is accompanied by a slow counterclockwise turning of the horizontal wave number vector a decrease in the intrinsic frequency and an increase in the vertical wavelength in qualitative agreement with the data a companion paper marmorino et al this issue details the effect of this inertial wave upon the small scale temperature activity with horizontal length scales of 1 3 m

entrainment results including advection and case studies from the flatland boundary layer experiments boundary layer top entrainment measurements from the 1996 flatland boundary layer experiment flatland96 were presented by angevine et al 1998a at that time no reliable estimates of temperature advection which could affect the heat budget approach used were available this paper presents the entrainment results recalculated with advection estimated from the national centers for environmental prediction mesoscale eta numerical model estimates of the contribution to entrainment by mechanical turbulence shear and of the shear free entrainment ratio are also calculated a number of case study examples are also presented to elucidate further the complex interactions that govern entrainment accounting for advection in the budgets results in a slightly smaller estimate of the entrainment ratio a r the mean a r is 0 47 0 11 and the median is 0 40 these results are still somewhat larger than long accepted values and comparable to results from some other studies in comparable conditions the experiments took place in the area near the flatland atmospheric observatory near champaign urbana illinois in june august 1996 the site is interesting because it is extraordinarily flat has uniform land use and is situated in a prime agricultural area

near inertial wave wake of hurricanes katrina and rita over mesoscale oceanic eddies abstract tropical cyclones tcs katrina and rita moved as major hurricanes over energetic geostrophic ocean features in the gulf of mexico increased and reduced oceanic mixed layer oml cooling was measured following the passage of both storms over cyclonic and anticyclonic geostrophic relative vorticity g respectively this contrasting thermal response is investigated here in terms of the evolution of the storms near inertial wave wake in geostrophic eddies observational data and ray tracing techniques in realistic geostrophic flow indicate that tc forced oml near inertial waves are trapped in regions of negative g where they rapidly propagate into the thermocline these anticyclonic rotating regimes coincided with the distribution of reduced oml cooling because rapid downward dispersion of near inertial energy reduced the amount of kinetic energy available to increase vertical shears at the oml base by contrast tc forced oml near inertial waves were stalled in upper layers of cyclonic circula

cyclonic eddies northeast of the campeche bank from altimetry data eight cyclonic eddies were identified near the western edge of the loop current at the northeast shelf break of the campeche bank through topex poseidon sea surface height anomaly data from january 1993 through march 2000 the eddies migration and their lifecycle are described the formation of the eddies appears to be related to the dynamics of the loop current because the timing of their generation corresponds to the last stage of the anticyclone shedding from the loop current the cyclones intensify while moving slightly to the northwest along the shelf break of the campeche bank later some cyclones are observed to move northward toward the mississippi shelf break the cyclones remain next to the campeche bank south of 268n from 1 3 to 9 6 months later some of them move northward and strengthen by merging with other eddies extending their life span the eddies vertical structure is analyzed with hydrographic data and the connection between the formation of the cyclones and the evolution of the loop current is further described using sea surface temperature images

hurricane forced upwelling and chlorophyll a enhancement within cold core cyclones in the gulf of mexico 1 clear skies subsequent to hurricane ivan s passage across the gulf of mexico in september 2004 provided a unique opportunity to investigate upper ocean responses to a major hurricane oceanic cyclonic circulation was rapidly intensified by the hurricane s wind field 59 62 m s 1 maximizing upwelling and surface cooling 3 7 c in two large areas along ivan s track upward isothermal displacements of 50 65 m computed from wind stress and sea surface height changes caused rapid ventilation of thermoclines and nutriclines leading to phytoplankton blooms with peak concentrations 3 4 days later wind speed changes along ivan s track demonstrated that the cool waters 20 26 c provided immediate negative feedback to the hurricane s intensity although our study focused on a relatively small ocean area it revealed that mesoscale cyclones in addition to warm anticyclones may play an important role in producing along track hurricane intensity changes

the inertial chimney the near inertial energy drainage from the ocean surface to the deep layer a three dimensional primitive equation numerical model is used to study the behavior of near inertial waves generated by surface wind stress on an plane the model is fixed depth with a rigid lid on the surface and is horizontally periodic this study shows the behaviors of the wind generated near inertial waves for four different eddies 1 a subtropical cold core eddy 2 a subtropical warm core eddy 3 a california subsurface warm core eddy and 4 the gulf stream warm core ring the mean secondary circulation generated by the wind eddy interaction has magnitude to comparable to that of the ekman current and its characteristics are determined by the relative angle between wind and current the propagation characteristics of near inertial waves are quite different depending upon the sign of the relative vorticity in a cyclonic eddy near inertial wave propagation is outward from the core of the eddy the propagation direction in an anticyclonic eddy is downward and toward the core vertically propagating waves inside the eddy are trapped above a critical layer and slowly dissipated by parameterized viscous effects the model shows that anticyclones efficiently drain near inertial energy from the surface to the deep layer below the thermocline

vertical structure of the ocean current response to a hurricane abstract during the passage of hurricane norbert in 1984 the hurricane research division of noaa conducted a planetary boundary layer experiment that included the deployment of airborne expendable current profilers axcp a total of 16 axcps provided for the fist time high resolution vertical profiles of currents and temperatures in hurricane wind conditions this study focuses on the vertical structure of the near inertial baroclinic current excited by the passage of this hurricane the transient hurricane induced currents are isolated from the axcp profiles in norbert by subtracting a spatially averaged current near the center of hurricane norbert the wkbj scaled vertical wavenumber spectra are a decade greater than the garrett munk spectra gm75 the fist ten linear baroclinic free modes are calculated from the spatially averaged brunt vaisala frequency to allow a more direct comparison with the axcp observations in the current wind regime the near inertial response for the three dimensional v

reply to the comment on physical and stable isotope evidence for formation of secondary calcite and silica in the unsaturated zone yucca mountain nevada by y v dublyansky s e smirnov and g p palyanova

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