variability in sediment delivery and storage along river courses in bega catchment nsw australia implications for geomorphic river recovery in many catchments in southeastern australia alluvial stores have been the dominant source of sediments mobilised in the period since european settlement in bega catchment on the south coast of new south wales nsw this has been reflected by dramatic changes to river morphology extensive volumes of material have been released and efficiently flushed to the lowland plain with a sediment delivery ratio of almost 70 however only 16 of these alluvial sediments have been flushed through to the estuary as antecedent controls on valley width have resulted in the lowland plain acting as a large sediment sink the changing nature of sediment source transfer and accumulation zones has varied markedly from subcatchment to subcatchment the volume of material supplied to the lowland plain from differing subcatchments is not related to subcatchment area rather the pattern of river types dictates the spatial variability in storage and transfer over 67 of sediment released has been sourced from just 25 of the catchment from subcatchments characterised by large valley fills cut and fill river style that previously stored extensive volumes of material at the base of the escarpment these parts of bega catchment were especially sensitive to disturbance sediment exhaustion from these parts of the catchment and from river courses elsewhere has major implications for the geomorphic recovery potential of rivers constraining what can be realistically achieved in terms of river rehabilitation

structural organization of process zones in upland watersheds of central nevada and its influence on basin connectivity dynamics and wet meadow complexes abstract the drainage network within upland watersheds in central nevada can be subdivided into distinct zones each dominated by a unique set of processes on the basis of valley form the geological materials that comprise the valley floor and the presence or absence of surficial channels on hillslopes the type and structure frequency length and spatial arrangement of these process zones is related to the lithology and weathering characteristics of the underlying bedrock process zones dominated by sediment accumulation storage and groundwater recharge are associated with less resistant rocks that weather into abundant but relatively small particles sediment transport and runoff dominated zones are associated with resistant sparsely fractured rocks that produce limited but larger clasts the type and structure of process zones along axial valleys depend on the characteristics of the process zones on the hillslopes numerous sediment storage dominated reaches leads to a relatively high number of unincised fans located at the mouth of tributaries along the axial valleys and to frequent and lengthy unincised valley segments both of which disconnect large sections of the drainage basin from channelized flows in contrast a relatively high density of transport dominated process zones leads downstream to the incision of side valley fans and axial valley deposits as well as a high degree of basin connectivity defined by the integration of surficial channels connectivity also is related to the lithology of the underlying bedrock with higher degrees of connectivity being associated with volcanic rocks that presumably yield high rates of runoff lower levels of connectivity are associated most frequently with extensively fractured locally permeable sedimentary and metamorphic rock assemblages thus basins underlain by volcanic rocks appear to be more sensitive to incision and produce more dynamic channels in terms of the rate of channel valley modification than those underlain by other lithologies considerable attention has been devoted in recent years to the management of wet meadow ecosystems that serve as important riparian habitats within upland basins of central nevada the data presented here show that within basins characterized by a high degree of connectivity areas of wet meadow are minimal where they do exist in these basins they tend to be severely degraded by incision or gully erosion and will be difficult to manage given the dynamic nature of the axial channel processes wet meadows within basins that exhibit a low degree of connectivity and high sediment storage to transport ratios on hillslopes will likely be more responsive to management activities because of the reduced threats of channel incision and presumably a larger supply of groundwater flow to the meadows created by an extensive network of recharge sites importantly human activities that lead to an increase in basin connectivity can negatively impact downstream meadows through a decrease in groundwater recharge and an increase in stream dynamics in spite of the fact that these activities may be physically separated from the wet meadow areas

frequency wavenumber spectra of sea surface temperature and wind stress curl in the eastern north pacific abstract frequency wavenumber spectra of sea surface temperature and wind stress curl are computed from 11 years of surface marine observations taken in the eastern north pacific these data were averaged by month and 2 quadrangles to yield spectra with periods from 2 to 48 months and zonal wavelengths from 400 to 4000 km spectra were computed for all 2 zonal bands between 16 and 40 n using data from the area between 120 and 160 w missing monthly values led to the computation of these spectra using a least squares fourier expansion which eliminated the need for temporal interpolation frequency spectra computed with this technique compare well with spectra using standard fourier methods the resulting spectra were found to separate naturally into two regions one between 29 and 40 n and the second between 15 and 29 n even within these zonal bands there were some important north south changes the annual signal was found to dominate the spectra of sea surface temperature at almost all wavelengths the

a gis based method for evaluating sediment storage and transport in large mining affected river systems currently the evaluation of sediment storage and transport for large river systems with variable flow has proven to be a challenge that often requires complex numerical models to be applied and sometimes costly direct data acquisition to be made the present study proposes a low cost widely available gis based method through which an initial assessment can be made on areas of sediment storage transport and deposition as well as possible environmental risks that the accumulation of contaminated material may pose to riverine communities along the rivers channel the method mainly relies on satellite imagery and elevation data to devise a quick model of the channel the model has been successfully applied to study the bolivian sector of the well known mining contaminated rio pilcomayo the analysis shows that the portion of the channel from villamontes to d orbigny accounts for more than half of the total c 314 km2 sedimentation area of the pilcomayo in bolivia and that the most environmentally problematic area is centreed around puente sucre where agriculture is practiced on the contaminated floodplain combined with supplementary bathymetric data on the depth of the river in various points around the channel the method could offer further insight into the sediment fluxes and transport capacity of the pilcomayo in various sectors and could thus be successfully used to assess other large mining contaminated river channels around the world

a new troodontid dinosauria theropoda braincase from the dinosaur park formation campanian of alberta a new well preserved specimen of troodon formosus is the first to reveal the internal anatomy of the lower part of the braincase in addition to providing new information on the brain of this high

coarse sediment connectivity in river channel systems a conceptual framework and methodology identification of coarse sediment connectivity down river channel systems is important for understanding the linkages between river reaches the influence of sediment sources on channel morphology and the mechanisms and liability to propagation of morphological change a conceptual framework is developed in which several types and degrees of connectivity are proposed it is hypothesised that sediment connectivity varies with sediment sources and with stream competence to transport the coarse fractions a method of identifying the status of reaches is developed based on field mapping of morphology and sedimentology the analysis is exemplified by two channels one an ephemeral channel in se spain the other a perennial channel in nw england questions arise over whether reaches that lack channel stores transfer coarse sediment three scenarios are suggested 1 lack of flux due to lack of competence of the reach 2 flushing through of sediment due to high competence and 3 potential transport of coarse sediment but exhaustion or lack of availability changes in connectivity will take place over different time scales depending on the nature of exchange and time scales of storage short term variations in connectivity can be identified by repeated mapping

spectral and empirical orthogonal function analysis of four years of european center for medium range weather forecast wind stress curl over the north atlantic ocean the wind stress curl is calculated from a 4 year european center for medium range forecast ecmwf data set over the north atlantic the mean wind stress curl appears as a northern positive cell of high amplitude and a large southern negative cell of lower amplitude the separating zero contour shows large scale meanders and is highly variable at the seasonal and annual cycles the rms of the wind stress curl is zonal and mainly contained in the short period band less than 10 days the frequency spectrum is nearly white north of 35 n in the south because of the lack of synoptic scale atmospheric storms the spectrum shows a f 0 6 dependency at frequencies higher than 1 20 cpd wave number spectra are white for wavelengths larger than 1200 km and decay like k 4 at shorter wavelengths the large scale variability is investigated by means of the empirical orthogonal function eof analysis for the nonsynoptic time scales periods of 10 days the most significant eofs display basin size oscillations with higher amplitude north of 35 n the associated time series present high variability at the seasonal cycle and a larger amplitude in winter these eofs are related to important features of the north atlantic climatology like the seasonal variability of the position of the icelandic low and the annual oscillation in intensity of the subpolar low and the subtropical high the first 10 eofs are above the noise level they are combined and compared to the initial data in order to produce realistic forcings for process studies in ocean modeling

variability of the wind stress curl over the north pacific implications for the oceanic response the subinertial frequency wavenumber structure and spatial coherence of wind stress curl and their spatial and temporal variability are described with the emphasis on characteristics which affect the ocean s response to the wind stress curl forcing function wind stress curl over the north pacific between 25 o and 60on was computed for 3 years 1985 1988 from the fleet numerical oceanography center wind product the range from winter peak to summer trough for the mean and variance are typically a factor of 3 4 and 10 respectively with superimposed interannual changes of up to a factor of 2 power spectra vary seasonally and interannually in an essentially frequency independent manner that is consistent with the curl variance however the spectrum over the period band 5 100 days often fails a statistical test for whiteness at the 95 level zonal and meridional wavenumber spectra were estimated for 13 sites distributed around the central eastern north pacific using the maximum likelihood method directional trends with frequency are comparable to those from earlier studies if 3 year long data segments are analyzed with approximate wavenumber symmetry except for the zonal term at mid latitudes for periods shorter than 10 days where eastward propagation is dominant however spectra for shorter data sections sometimes display eastward and westward excursions which are only weakly similar over distances of 1000 km and essentially dissimilar over longer separations the spatial correlation structure of wind stress curl is shown typically to have a main lobe of 1000 km and multiple intercorrelation lobes separated by 2000 km the strength and location of the intercorrelation peaks vary slowly with time these results suggest that curl behavior is more complex than was previously believed that the use of long term averages of or simple parameterizations for the frequency wavenumber spectrum of wind stress curl in model studies may be unrealistic and that more attention to actual curl characteristics at the time oceanic measurements are collected will be required to reconcile models with observations

the barotropic electromagnetic and pressure experiment 1 barotropic current response to atmospheric forcing during 1986 1987 an array of horizontal electrometers which measure the subinertial barotropic velocity was deployed for 11 months in the central north pacific to study atmospherically forced motions in a low eddy kinetic energy region significant coherence is found to be ubiquitous between the barotropic velocity and one or more surface atmospheric variables over the north pacific the maximum squared coherence between currents and wind stress curl at all periods greater than 3 days is typically 0 6 rarely below 0 4 and occasionally above 0 8 and is dominantly nonlocal although local coherence is seen at some sites especially at the shorter periods both the coherence and the intersite pattern similarity are strongest at the periods of relative maxima in the barotropic current autospectra e g at 6 8 10 14 and 20 50 days the locations at which the wind stress curl forces the motions at each site and for each period have been determined while there is substantial intersite variability some of the observed patterns of squared coherence over the north pacific are very similar to those predicted by simple linear smooth bottomed quasi geostrophic models of atmospherically forced barotropic currents the forcing location is occasionally found to be the same spot for all oceanic instruments especially at the autospectral maxima in barotropic current more commonly distinct forcing locations are found for each instrument even when closely spaced suggesting topographic influence in other cases multiple forcing locations are implicated for the motions at a single station all of this site and period dependent variability of the forcing location is incompatible with the simple models and is due either to the known spatial inhomogeneity of the curl forcing field or to topographic effects the importance of the former is emphasized using simple arguments based on analytic transfer functions between the atmospheric and oceanic variables and on observed wavenumber spectra for wind stress curl quantitative assessment of topographic effects must await suitable numerical models in addition maximum likelihood wavenumber spectra of the barotropic currents have been estimated in those bands with an adequate number of coherent sensors the wavenumbers at the spectral peaks are compatible with the dispersion relation for rossby waves modified by the observed large scale linearly sloping topography which shoals to the northeast the observed group velocities are in general quite consistent with the inferred forcing locations based on the ocean atmosphere coherences

channel reach morphology in mountain drainage basins a classification of channel reach morphology in mountain drainage basins synthesizes stream morphologies into seven distinct reach types colluvial bedrock and five alluvial channel types cascade step pool plane bed pool rime and dune ripple coupling reach level channel processes with the spatial arrangement of reach morphologies their links to hillslope processes and external forcing by confinement ripar ian vegetation and woody debris defines a process based framework within which to assess channel condition and response potential in mountain drainage basins field investigations demonstrate character istic slope grain size shear stress and roughness ranges for different reach types observations consistent with our hypothesis that alluvial channel morphologies reflect specific roughness configurations ad justed to the relative magnitudes of sediment supply and transport ca pacity steep alluvial channels cascade and step pool have high ratios of transport capacity to sediment supply and are resilient to changes in discharge and sediment supply whereas low gradient alluvial channels pool rime and dune ripple have lower transport capacity to supply ra tios and thus exhibit significant and prolonged response to changes in sediment supply and discharge general differences in the ratio of transport capacity to supply between channel types allow aggregation of reaches into source transport and response segments the spatial distribution of which provides a watershed level conceptual model linking reach morphology and channel processes these two scales of channel network classification define a framework within which to in vestigate spatial and temporal patterns of channel response in moun tain drainage basins

influence of late holocene hillslope processes and landforms on modern channel dynamics in upland watersheds of central nevada stratigraphic geomorphic and paleoecological data were collected from upland watersheds in the great basin of central nevada to assess the relationships between late holocene climate change hillslope processes and landforms and modern channel dynamics these data indicate that a shift to drier warmer climatic conditions from approximately 2500 to 1300 ypb led to a complex set of geomorphic responses the initial response was massive hillslope erosion and the simultaneous aggradation of both side valley alluvial fans and the axial valley system the final response was fan stabilization and axial channel incision as fine grained sediments were winnowed from the hillslope sediment reservoirs and sediment yield and runoff processes were altered the primary geomorphic response to disturbance for approximately the past 1900 years has been channel entrenchment suggesting that the evolutionary history of hillslopes has produced watersheds that are prone to incision the magnitude of the most recent phase of channel entrenchment varies along the valley floor as a function of geomorphic position relative to side valley alluvial fans radial fan profiles suggest that during fan building fan deposits temporarily blocked the flow of sediment down the main stem of the valley commonly creating a stepped longitudinal valley profile stream reaches located immediately upvalley of these fans are characterized by low gradients and alternating episodes of erosion and deposition in contrast reaches coincident with or immediately downstream of the fans exhibit higher gradients and limited valley floor deposition thus modern channel dynamics and associated riparian ecosystems are strongly influenced by landforms created by depositional events that occurred approximately 2000 years ago

a local time dependent sverdrup balance in the eastern north pacific ocean direct observations of the dynamic balance between time dependent winds and deep ocean currents are described for the eastern north pacific ocean at 42 n 152 w currents from 150 to 4000 meters below the surface at frequencies from 0 01 to 0 1 cycle per day are significantly correlated with the wind stress curl derived from u s navy operational wind fields the horizontal currents are depth independent below 300 meters and they flow parallel to the potential vorticity gradient derived from the earth9s rotation and the large scale bottom topography these characteristics are expected for such periodic motions with horizontal scales larger than 500 kilometers and represent a generalized sverdrup balance between the atmospheric forcing and the oceanic response

the influence of landscape connectivity and landslide dynamics upon channel adjustments and sediment flux in the liwu basin taiwan catchment scale analyzes of spatial and temporal variability in landscape connectivity are critical considerations in appraisals of landscape evolution and disaster mitigation in tectonically active mountain belts such as taiwan this study uses historical aerial photographs flow discharge and seismic data to analyze landslide changes and channel adjustments over a 30 year period in the liwu basin recurrent earthquakes and typhoon events trigger frequent landslide activity channel adjustment and sediment reworking in this system spatial variability in magnitude frequency relations of hillslope valley floor lateral and upstream downstream longitudinal connectivity during the study period are shown to reflect annual reworking in source and accumulation zones while partly confined valleys in the mid catchment area trap sediment behind landslide induced dams that are formed and breached on an approximately decadal basis this promotes partial longitudinal connectivity in these areas landscape responses to disturbance events were especially pronounced following combinations of seismic and typhoon events prior to the 1998 and 2005 images although single high magnitude events and series of moderate events affect patterns of landscape connectivity in the liwu basin residence times for sediment storage are very short in this highly connected river system where confined valley settings extend virtually to the coast copyright 2014 john wiley sons ltd

stochastically forced current fluctuations in vertical shear and over topography the effects of constant vertical shear of zonal velocity uniform meridional bottom slope and a deep meridional wall representing the mid atlantic ridge on the response of a linear two layer quasi geostrophic ocean to stochastic wind stress curl forcing are investigated the model is motivated by discrepancies in energy levels and distributions between recent observations and a similar model without shear or topography that predicted remote coherences relatively well the results indicate that the presence of mean shear can significantly enhance the wind generation of surface intensified oceanic kinetic energy at frequencies above the zero shear cutoff for free baroclinic waves the primary effect of the sloping topography is enhanced barotropic response near the barotropic topographic sverdrup resonance where topographic and planetary potential vorticity gradients cancel the wall inhibits the barotropic response and increases coherences on the mooring side of the wall remote coherences for 49 day period fluctuations are due to long barotropic waves as in the previous model so the present model only partially reconciles the previous discrepancies

observations of wind forced deep ocean currents in the north pacific this study examines the atmospheric response of the deep ocean using 200 instrument years of moored current measurements from across the breadth of the mid latitude north pacific we have found evidence of a seasonal modulation in the ocean eddy kinetic energy beneath the thermocline at several locations north of 35 n this modulation is often in phase with the local atmospheric forcing function at frequencies between 0 1 and 0 01 cpd correlations between the local wind stress curl and the deep currents have been found for a few locations the local forced response is parallel to the potential vorticity gradient f h and consistent in amplitude with a local topographic sverdrup balance nonlocal forcing in the form of flow along isolines of potential vorticity has been estimated and it is comparable to the observed flow at some locations but the modeled flow is not correlated with the observations throughout the mid latitude north pacific the bottom slope tends to enhance the effect this suggests that topography narrows the available bandwidth for forced barotropic rossby waves facilitating a quasi steady topographic sverdrup response over most of the basin however the enhanced effect reduces the magnitude of the ocean s response to wind forcing nonlocally forced sverdrup currents flow along isolines of f h are the dominant component but are only of the order of 1 cm s 1 locally forced sverdrup currents flow across isolines of f h are typically of the order of 0 1 cm s 1 rms and are not commonly measured hence these wind forced variations are a background level signal in the mid latitude eddy kinetic energy in a few isolated areas the bottom slope reduces the effect in these regions the local sverdrup response is amplified and has been observed

interdecadal variations in the alaska gyre abstract climatic dynamic topography variations in the alaska gyre during the period 1968 1990 are described with an objective analysis of more than 12000 std and xbt stations and coads wind stress data interannual dynamic height and sst variations were correlated and were consistent with recently described large scale climatic shifts in the north pacific the gyre was cantered more to the east circulation appeared stronger and sst was lower during the early to mid 1970s than during the 1980s the aleutian low np and pna indices intensified during the interim but the response did not appear as a gyre spinup instead the associated wind stress anomalies forced a slowly varying dynamic height anomaly across the eastern and northern part of the gyre through ekman convergence which had the effect of displacing the gyre s low somewhat to the wsw in the 1980s the wind curl spectrum was white and the slow oceanic response was modelled as stochastic forced climate variability with a simple first order m

a seasonal signal in ocean currents to abyssal depths long term 9 32 month current meter records from the eastern north atlantic 41 n 59 n suggest that remote from the influence of the western boundary current eddy kinetic energy ke at all depths is principally a function of wind stress and stratification generated during the winter and early spring propagating to abyssal depths and decaying to a minimum in late summer although this seasonal variation in ke has not previously been described from the midlatitude ocean some theoretical basis for it is presented

near bottom currents at station m in the abyssal northeast pacific abstract deep sea currents in the northeast pacific ocean are examined using observations at station m located on the abyssal plain 220 km offshore of central california collected near the seabed at 4000 m depth from october 2014 october 2018 the current meter observations supplement long term investigations of deep sea benthic ecology at this site to investigate mechanisms for variability at different time scales the observed currents are separated into low frequency fluctuations with periods of 1 4 60 days fluctuations that are coherent with astronomical tidal forcing and other high frequency fluctuations these motions contribute similarly to the overall variability at this location low frequency currents exhibit elevated energy at periods of 30 days consistent with previous observations elsewhere in the abyssal north pacific however unlike some other observations in the deep ocean there is no consistent seasonal cycle in the variability of low frequency motion the theoretical prediction of sverdrup balance between transport and local wind stress curl does not explain the timing or the magnitude of low frequency currents suggesting that they are driven by remote winds or eddy dynamics the non tidal high frequency fluctuations show evidence of a near inertial peak and clockwise rotary motion consistent with theoretical expectations for the internal gravity wave spectrum like the low frequency currents interannual variability of internal wave energy appears to be stronger than seasonal variability observations of the vertical structure 2 5 17 5 m above bottom are used to characterize the interactions between currents and the seabed observational estimates of diurnal and semidiurnal tidal ellipses are consistent with results from an analytical model that incorporates the effects of the earth s rotation and tidal acceleration a numerical model of the time dependent boundary layer provides estimates of bottom roughness and friction velocity that are consistent with previous observations at this site this study shows that the strength time scale and polarization of the near bottom currents at station m vary significantly between years demonstrating the value of multi year records in studies of the lateral transport of organic matter sediment and organisms at this abyssal site

large scale sst variability in the western north atlantic subtropical convergence zone during fasinex part i description of sst and wind stress fields abstract we describe properties of large scale fluctuations in the wind field represented by two analyses fnoc and noaa atoll and in the sst field represented by maps derived from 5 day composite avhrr images within an 11 longitude by 10 latitude domain during fasinex january through june 1986 fnoc and atoll wind and wind stress time series were highly correlated with each other 0 8 over the entire domain and they were also highly correlated with time series measured at the fasinex site 0 89 at periods of 2 13 days clockwise energy exceeded anticlockwise energy by an order of magnitude while the energy was nearly partitioned equally at periods of 13 40 days mean atoll winds were everywhere more eastward than mean fnoc winds probably in part because the atoll fnoc analyses are intended to represent 850 mb 19 5 m winds the 850 mb winds are expected to be more eastward due to the thermal wind balance with the mean southward air temperature gradient the sst maps represented large s

wind forced variability of the deep eastern north pacific observations of seafloor pressure and abyssal currents data from an array of bottom pressure gauges and a string of current meters in the vicinity of 47on 139ow are used to examine the deep ocean variability forced by ocean surface wind stress curl from august 1987 to june 1988 bottom geostrophic currents are computed from the pressure gauge array and these correspond well to the long period directly measured currents at 3000 m the supratidalperiod bottom pressure variations are coherent at 95 confidence with the wind stress curl in period bands of 3 4 days and 15 60 days but removed in distances of 400 and 700 km to the northwest and the southeast respectively a linear two layer hydrodynamic model is used to examine the theoretical forcing produced by random phased surface wind fields for the conditions of the eastern north pacific and the 15 to 60 day period observed response is reproduced credibly to model 3 to 15 day variations more realistic models are required currents are related to surface winds were derived from yearlong current meter records in a cluster of moorings north and east of barbados koblinsky and niiler 1982 showed that significant coherences existed between the 4 to 40 dayperiod east west pulsations of the trade winds r x above barbados and the north south currents v at all depths in the ocean at 15on 54ow the response amplitude of v to r x was depth and period dependent it decreased by a factor of 3 from 150 to 4000 m depths and increased by a factor of 5 from 8 to 40 day periods the interpretation of these data was that the deep ocean forcing was produced by large horizontal scale wind stress curl hereinafter referred to simply as curl due to westward propagating pulses in the trade winds with larger east west than north south scale the amplitude of the deep wind related currents was 1 3 cm s thus deep ocean forcing should be observable in many places where the mesoscale eddy energy is low theoretically wind forced deep ocean motions should depend upon wind stress curl mt iller and frankignoul 1981 using a model of randomly forced linear motions in a stratified infinite flat bottom beta plane ocean computed local coherences and showed that motions across the planetary vorticity gradient should exhibit the strongest coherence with the local wind stress curl niiler and koblinsky 1985 using current meter data demonstrated that such a dynamical link does in fact exist locally at 42on 152ow although at a shorter period than was predicted by milller and frankignoul both the amplitude and the phase of the currents that were forced across the planetary potential vorticity field orf h contours on a 150 km horizontal scale were predicted from the local surface wind stress computed from a similar 150 km scale wind field the 4000 m oscilla

the 1986 87 pacific warm episode evolution of oceanic and atmospheric anomaly fields abstract the evolution of oceanic and atmospheric anomaly fields for the period prior to and during the 1986 87 el nino southem oscillation enso is presented a comparison is made between the 1986 87 enso and other warm episodes that occurred during the last 20 yr in addition for the first time an ocean general circulation model was run in a real time diagnostic mode the model output provided detailed information about the evolution of subsurface features throughout the pacific basin a slow trend towards warm episode enso conditions in the pacific was evident throughout the period 1985 86 in certain atmospheric and oceanic variables atmospheric and oceanic fields changed much more rapidly during late 1986 as enhanced atmospheric convection developed in the equatorial pacific near the date line thermocline depths rapidly increased decreased in the eastern western equatorial pacific as low level westerlies developed in the western portion of the basin a remote response to those westerlies wa

on climatological monthly mean wind stress and wind stress curl fields over the world ocean abstract using a version of the global surface marine observation historical data set a new 1 spatial resolution global ocean surface wind stress climatology has been evaluated using the large and pond surface drag coefficient formulation these new results are compared after spatial smoothing with those of hellerman and rosenstein who used a different drag coefficient form it is found that the new stresses are almost everywhere smaller than those of hellerman and rosenstein often by 20 30 which is greater than the formal error estimates from their calculations the stress differences show large scale spatial structure as would he expected given the spatial variation of the surface stability parameter and the known different wind variability regions basin zonally averaged ekman transports are computed to provide perspective on the significance of the stress differences annual mean differences can exceed 10 sv sv 106 m3 s 1 equatorward of 20 lat but are smaller poleward wind stress curl

evidence for wind driven current fluctuations in the western north atlantic two subsurface current meter moorings were deployed for 20 months along 70 w in a low energy portion of the western north atlantic the resulting data were compared with estimates of the wind stress curl in an attempt to seek a relationship between currents below the mixed layer and meteorological forcing at subinertial frequencies currents and temperature tend to be significantly coherent with the curl and are most coherent with the curl at remote locations usually more than 500 km away from the mooring and generally to the east coherences generally decrease with increasing frequency the current response is surface intensified a linear stratified model for stochastically wind forced rossby waves in a flat bottomed ocean is presented as an attempt to rationalize the results the effort was not entirely successful so that it appears that a more realistic model perhaps including bottom topography and mean currents will be needed to rationalize these observations fully

spatial and temporal characteristics of the wind forcing of the bering sea abstract the surface wind stress over the bering sea is estimated for the period 1946 90 from sea level pressure analyses empirical relationships between the geostrophic wind and the surface wind and a bulk aerodynamic formula the focus is on the propagation and variability of the stress and the curl of the stress as a function of frequency the stress at high frequencies 0 1 cpd is dominated by northward and eastward propagating disturbances with mean wavelengths of 2500 and 10 000 km respectively at periods of 10 100 days the mean propagation is near zero there are however significant interannual variations in the zonal propagation wind driven ocean transports estimated by the sverdrup method for the deep bering basin account for 6 sv or roughly one half of the observed transport within the western boundary current along the kamchatka peninsula a low pass filtered retaining periods greater than 18 months time series of the sverdrup transport exhibits a standard deviation of 25 of th

stochastic forcing of the north atlantic wind driven ocean circulation part i a diagnostic analysis of the ocean response to stochastic forcing abstract at midlatitudes the magnitude of stochastic wind stress forcing due to atmospheric weather is comparable to that associated with the seasonal cycle stochastic forcing is therefore likely to have a significant influence on the ocean circulation in this work the influence of the stochastic component of the wind stress forcing on the large scale wind driven circulation of the north atlantic ocean is examined to this end a quasigeostrophic model of the north atlantic was forced with estimates of the stochastic component of wind stress curl obtained from the ncar community climate model analysis reveals that much of the stochastically induced variability in the ocean circulation occurs in the vicinity of the western boundary and some major bathymetric features thus the response is localized even though the stochastic forcing occurs over most of the ocean basin using the ideas of generalized stability theory the stochastically induced response in the ocean circulation can be interpreted as