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1
Gamagami, Reza. "Response to Dr. Eke." American Journal of Gastroenterology 94, no. 3 (March 1999): 858–59. http://dx.doi.org/10.1111/j.1572-0241.1999.0858a.x.
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Perkinson, Eliza. "He waka eke noa!" Aotearoa New Zealand Social Work 32, no. 2 (August 5, 2020): 71–72. http://dx.doi.org/10.11157/anzswj-vol32iss2id745.
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Out of the response to Covid-19 emerged a message: he waka eke noa. This whakatauki, which directly translates to mean, “we are all in this together”, was used to unite Aotearoa New Zealand in our efforts against the virus. It refers to a waka of collective consciousness guiding us on the same journey. But were we united? Were we truly in this waka (canoe), of five million together?
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Volkov, Denis L. "Interannual Variability of the Altimetry-Derived Eddy Field and Surface Circulation in the Extratropical North Atlantic Ocean in 1993–2001." Journal of Physical Oceanography 35, no. 4 (April 1, 2005): 405–26. http://dx.doi.org/10.1175/jpo2683.1.
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Abstract The distribution of surface eddy kinetic energy (EKE) depicts main oceanic surface circulation features. The interannual variability of EKE and associated geostrophic velocity anomalies in the North Atlantic Ocean were analyzed to describe the variations in oceanic currents between 1993 and 2002. The sea level anomaly maps of the combined TOPEX/Poseidon + ERS-1/2 and TOPEX/Poseidon-alone satellite altimetry data were used to derive EKE. The study focused on the areas of the Gulf Stream extension (GS), North Atlantic Current (NAC), Azores Current (AC), and the northeastern (Rockall Channel and Iceland Basin) and northwestern (Irminger Basin and Labrador Sea) North Atlantic. The interannual variability of the altimetry-derived EKE field in the GS extension area reflected the meridional displacements of the GS core described in earlier studies. The interannual change of EKE in the AC was characterized by high values in 1993–95 followed by lower EKE in subsequent years. The interannual variability of EKE in the NAC area west of the Mid-Atlantic Ridge exhibited an out-of-phase change between the band centered at ∼47°N and two bands on either side centered at ∼43° and ∼50°N. In the Rockall Channel the geostrophic velocity anomalies indicated an intensified northeastward flow in 1993–95 followed by a relaxation in 1996–2000. The EKE band associated with the NAC branch in the Iceland Basin was found to be extended farther west after 1996, possibly following the North Atlantic Oscillation (NAO)-induced shift of the subpolar front. A rise of EKE was observed in the Irminger Basin from 1995 to 1999. This rise may have been associated with large anticyclonic geostrophic velocity anomalies, which indicated significant weakening of the cyclonic circulation in the Irminger Basin after 1996, and/or with possibly intensified eddy generation mechanisms due to the NAO-induced approach of the subpolar front. The interannual change of EKE in the Labrador Sea did not appear to always follow the atmospheric forcing expressed by NAO. Therefore other eddy generation mechanisms in the Labrador Sea can be important.
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Tallapally, Shirisha. "IMPERSONATION ATTACK ON EKE PROTOCOL." International journal of Network Security & Its Applications 2, no. 2 (April 25, 2010): 114–21. http://dx.doi.org/10.5121/ijnsa.2010.2209.
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Snook, Linda S. "From A to Z-Eke." Hospital Topics 64, no. 3 (June 1986): 38–40. http://dx.doi.org/10.1080/00185868.1986.9952442.
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VOITH, MELODY. "CHEMICAL FIRMS EKE OUT EARNINGS." Chemical & Engineering News 87, no. 30 (July 27, 2009): 11. http://dx.doi.org/10.1021/cen-v087n030.p011.
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Jung, Ji Yun, Sang Mi Park, Hae Li Ko, Jong Rok Lee, Chung A. Park, Sung Hui Byun, Sae Kwang Ku, Il Je Cho, and Sang Chan Kim. "Epimedium koreanum Ameliorates Oxidative Stress-Mediated Liver Injury by Activating Nuclear Factor Erythroid 2-Related Factor 2." American Journal of Chinese Medicine 46, no. 02 (January 2018): 469–88. http://dx.doi.org/10.1142/s0192415x18500246.
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Oxidative stress induced by reactive oxygen species is the main cause of various liver diseases. This study investigated the hepatoprotective effect of Epimedium koreanum Nakai water extract (EKE) against arachidonic acid (AA)[Formula: see text][Formula: see text][Formula: see text]iron-mediated cytotoxicity in HepG2 cells and carbon tetrachloride (CCl4-)-mediated acute liver injury in mice. Pretreatment with EKE (30 and 100[Formula: see text][Formula: see text]g/mL) significantly inhibited AA[Formula: see text][Formula: see text][Formula: see text]iron-mediated cytotoxicity in HepG2 cells by preventing changes in the expression of cleaved caspase-3 and poly(ADP-ribose) polymerase. EKE attenuated hydrogen peroxide production, glutathione depletion, and mitochondrial membrane dysfunction. EKE also increased the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2), transactivated anti-oxidant response element harboring luciferase activity, and induced the expression of anti-oxidant genes. Furthermore, the cytoprotective effect of EKE against AA[Formula: see text][Formula: see text][Formula: see text]iron was blocked in Nrf2 knockout cells. Ultra-performance liquid chromatography analysis showed that EKE contained icariin, icaritin, and quercetin; icaritin and quercetin were both found to protect HepG2 cells from AA[Formula: see text][Formula: see text][Formula: see text]iron via Nrf2 activation. In a CCl4-induced mouse model of liver injury, pretreatment with EKE (300[Formula: see text]mg/kg) for four consecutive days ameliorated CCl4-mediated increases in serum aspartate aminotransferase activity, histological activity index, hepatic parenchyma degeneration, and inflammatory cell infiltration. EKE also decreased the number of nitrotyrosine-, 4-hydroxynonenal-, cleaved caspase-3-, and cleaved poly(ADP-ribose) polymerase-positive cells in hepatic tissues. These results suggest EKE is a promising candidate for the prevention or treatment of oxidative stress-related liver diseases via Nrf2 activation.
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Guo, Yanjuan, and Edmund K. M. Chang. "Impacts of Assimilation of Satellite and Rawinsonde Observations on Southern Hemisphere Baroclinic Wave Activity in the NCEP–NCAR Reanalysis." Journal of Climate 21, no. 13 (July 1, 2008): 3290–309. http://dx.doi.org/10.1175/2007jcli2189.1.
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Abstract In this study, the impacts of the assimilation of satellite and rawinsonde observations on Southern Hemisphere (SH) baroclinic wave activity in the NCEP–NCAR reanalysis are examined by comparing analyses made with and without the assimilation of satellite data (SAT and NOSAT, respectively) for the year 1979, as well as by comparing analyses to the corresponding first guesses from 1958 to 1999. Comparing the eddy kinetic energy (EKE) computed based on the SAT and NOSAT analyses, it is found that the assimilation of satellite data generally decreases the EKE in the SH, which is the opposite of the findings for the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) in previous studies. The decrease of EKE by satellite data in the NCEP–NCAR reanalysis can be traced back to a low bias in retrieved satellite temperature (SATEMP) variance. The eddy available potential energy (EPE) is decreased even more than the EKE with the assimilation of SATEMP, making the waves more barotropic in the SAT analysis. The EKE analysis increment, that is, the difference between the EKE based on analysis and first guess, is a good quantity to indicate the impacts of all observations assimilated. In the NOSAT analysis, positive EKE analysis increments are found around the SH rawinsonde stations, indicating that the assimilation of rawinsonde data increases EKE significantly from the first guess. This also suggests that the NCEP–NCAR first guess is probably biased low. Positive analysis increments around the rawinsonde stations become even larger in the SAT analysis compared with the NOSAT, suggesting that with the assimilation of low-biased SATEMP data, the EKE in the analysis (the initial condition for next time) and hence the first guess is reduced, therefore the rawinsonde observations have to further increase the EKE from the first guess. The patterns of EKE increment from the presatellite (1958–77) and satellite (1979–99) eras show high degrees of similarities to the NOSAT and SAT reanalysis patterns, respectively, lending further support to these findings. The impact of the assimilation of satellite data on the trend of SH baroclinic wave activity is discussed. Positive trends in the SH EKE are found in both the NCEP–NCAR and ERA-40 reanalyses during 1958–99. After taking the impacts of satellite data into account, the EKE trend in the NCEP–NCAR reanalysis gets stronger, while that in the ERA-40 is largely weakened, which adds complications to assessing the real trend in SH baroclinic wave activity. Comparisons among the variances based on the two reanalyses, NCEP–NCAR first guess, SATEMP, and rawinsonde observations are presented to substantiate some of the findings discussed above, such as the low bias in energy in NCEP–NCAR first guess and SATEMP variance.
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Penduff, Thierry, Bernard Barnier, W. K. Dewar, and James J. O'Brien. "Dynamical Response of the Oceanic Eddy Field to the North Atlantic Oscillation: A Model–Data Comparison." Journal of Physical Oceanography 34, no. 12 (December 1, 2004): 2615–29. http://dx.doi.org/10.1175/jpo2618.1.
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Abstract Observational studies have shown that in many regions of the World Ocean the eddy kinetic energy (EKE) significantly varies on interannual time scales. Comparing altimeter-derived EKE maps for 1993 and 1996, Stammer and Wunsch have mentioned a significant meridional redistribution of EKE in the North Atlantic Ocean and suggested the possible influence of the North Atlantic Oscillation (NAO) cycle. This hypothesis is examined using 7 yr of Ocean Topography Experiment (TOPEX)/Poseidon altimeter data and three ⅙°-resolution Atlantic Ocean model simulations performed over the period 1979–2000 during the French “CLIPPER” experiment. The subpolar–subtropical meridional contrast of EKE in the real ocean appears to vary on interannual time scales, and the model reproduces it realistically. The NAO cycle forces the meridional contrast of energy input by the wind. The analysis in this paper suggests that after 1993 the large amplitude of the NAO cycle induces changes in the transport of the baroclinically unstable large-scale circulation (Gulf Stream/North Atlantic Current) and, thus, changes in the EKE distribution. Model results suggest that NAO-like fluctuations were not followed by EKE redistributions before 1994, probably because NAO oscillations were weaker. Strong NAO events after 1994 were followed by gyre-scale EKE fluctuations with a 4–12-month lag, suggesting that complex, nonlinear adjustment processes are involved in this oceanic adjustment.
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Yang, Yang, X. San Liang, Bo Qiu, and Shuiming Chen. "On the Decadal Variability of the Eddy Kinetic Energy in the Kuroshio Extension." Journal of Physical Oceanography 47, no. 5 (May 2017): 1169–87. http://dx.doi.org/10.1175/jpo-d-16-0201.1.
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AbstractPrevious studies have found that the decadal variability of eddy kinetic energy (EKE) in the upstream Kuroshio Extension is negatively correlated with the jet strength, which seems counterintuitive at first glance because linear stability analysis usually suggests that a stronger jet would favor baroclinic instability and thus lead to stronger eddy activities. Using a time-varying energetics diagnostic methodology, namely, the localized multiscale energy and vorticity analysis (MS-EVA), and the MS-EVA-based nonlinear instability theory, this study investigates the physical mechanism responsible for such variations with the state estimate from the Estimating the Circulation and Climate of the Ocean (ECCO), Phase II. For the first time, it is found that the decadal modulation of EKE is mainly controlled by the barotropic instability of the background flow. During the high-EKE state, violent meanderings efficiently induce strong barotropic energy transfer from mean kinetic energy (MKE) to EKE despite the rather weak jet strength. The reverse is true in the low-EKE state. Although the enhanced meander in the high-EKE state also transfers a significant portion of energy from mean available potential energy (MAPE) to eddy available potential energy (EAPE) through baroclinic instability, the EAPE is not efficiently converted to EKE as the two processes are not well correlated at low frequencies revealed in the time-varying energetics. The decadal modulation of barotropic instability is found to be in pace with the North Pacific Gyre Oscillation but with a time lag of approximately 2 years.
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Hsu, Pang-chi, Tim Li, and Chih-Hua Tsou. "Interactions between Boreal Summer Intraseasonal Oscillations and Synoptic-Scale Disturbances over the Western North Pacific. Part I: Energetics Diagnosis*." Journal of Climate 24, no. 3 (February 1, 2011): 927–41. http://dx.doi.org/10.1175/2010jcli3833.1.
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Abstract The role of scale interactions in the maintenance of eddy kinetic energy (EKE) during the extreme phases of the intraseasonal oscillation (ISO) is examined through the construction of a new eddy energetics diagnostic tool that separates the effects of ISO and a low-frequency background state (LFBS; with periods longer than 90 days). The LFBS always contributes positively toward the EKE in the boreal summer, regardless of the ISO phases. The synoptic eddies extract energy from the ISO during the ISO active phase. This positive barotropic energy conversion occurs when the synoptic eddies interact with low-level cyclonic and convergent–confluent ISO flows. This contrasts with the ISO suppressed phase during which the synoptic eddies lose kinetic energy to the ISO flow. The anticyclonic and divergent–diffluent ISO flows during the suppressed phase are responsible for the negative barotropic energy conversion. A positive (negative) EKE tendency occurs during the ISO suppressed-to-active (active-to-suppressed) transitional phase. The cause of this asymmetric EKE tendency is attributed to the spatial phase relation among the ISO vorticity, eddy structure, and EKE. The southwest–northeast-tilted synoptic disturbances interacting with cyclonic (anticyclonic) vorticity of ISO lead to a positive (negative) EKE tendency in the northwest region of the maximum EKE center. The genesis number and location and intensification rate of tropical cyclones in the western North Pacific are closely related to the barotropic energy conversion. The enhanced barotropic energy conversion favors the generation and development of synoptic seed disturbances, some of which eventually grow into tropical cyclones.
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Zhai, Xiaoming. "The annual cycle of surface eddy kinetic energy and its influence on eddy momentum fluxes as inferred from altimeter data." Satellite Oceanography and Meteorology 2, no. 2 (October 19, 2017): 299. http://dx.doi.org/10.18063/som.v2i2.299.
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The annual cycle of surface eddy kinetic energy (EKE) and its influence on eddy momentum fluxes are investigated using an updated record of satellite altimeter data. It is found that there is a phase difference between the annual cycles of EKE in the western boundary current regions and EKE in the interior of the subtropical gyres, suggesting that different mechanisms may be at work in different parts of the subtropical gyres. The annual cycles of EKE averaged in the two hemispheres are found to be of similar magnitude but in opposite phase. As a result, the globally-averaged EKE shows little seasonal variability. The longer record of altimeter data used in this study has brought out a clearer and simpler picture of eddy momentum fluxes in the Gulf Stream and Kuroshio Extension. Considerable seasonal variations in eddy momentum fluxes are found in the western boundary current regions, which potentially play an important role in modulating the strength of the western boundary currents and their associated recirculation gyres on the seasonal time scale.
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Wang, Shengpeng, Zhao Jing, Qiuying Zhang, Ping Chang, Zhaohui Chen, Hailong Liu, and Lixin Wu. "Ocean Eddy Energetics in the Spectral Space as Revealed by High-Resolution General Circulation Models." Journal of Physical Oceanography 49, no. 11 (November 2019): 2815–27. http://dx.doi.org/10.1175/jpo-d-19-0034.1.
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AbstractIn this study, the global eddy kinetic energy (EKE) budget in horizontal wavenumber space is analyzed based on 1/10° ocean general circulation model simulations. In both the tropical and midlatitude regions, the barotropic energy conversion from background flow to eddies is positive throughout the wavenumber space and generally peaks at the scale (Le) where EKE reaches its maximum. The baroclinic energy conversion is more pronounced at midlatitudes. It exhibits a dipolar structure with positive and negative values at scales smaller and larger than Le, respectively. Surface wind power on geostrophic flow results in a significant EKE loss around Le but deposits energy at larger scales. The interior viscous dissipation and bottom drag inferred from the pressure flux convergence act as EKE sink terms. The latter is most efficient at Le while the former is more dominant at smaller scales. There is an evident mismatch between EKE generation and dissipation in the spectral space especially at the midlatitudes. This is reconciled by a dominant forward energy cascade on the equator and a dominant inverse energy cascade at the midlatitudes.
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Decker, Steven G., and Jonathan E. Martin. "A Local Energetics Analysis of the Life Cycle Differences between Consecutive, Explosively Deepening, Continental Cyclones." Monthly Weather Review 133, no. 1 (January 1, 2005): 295–316. http://dx.doi.org/10.1175/mwr-2860.1.
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Abstract Local energetics diagnostics of the life cycles of consecutive, explosively deepening, extratropical cyclones that migrated across central North America in April 2001 are presented. Both storms developed rapidly and followed nearly identical tracks through the region. Despite similar mature-stage intensities, the two storms underwent vastly different evolutions during cyclolysis; the first decayed as rapidly as it had developed, and the second decayed very slowly. Examination of the volume-integrated eddy kinetic energy (EKE) budget for each storm reveals that the sea level pressure minimum associated with the first cyclone developed well after its associated EKE center had reached its maximum intensity. In contrast, the second cyclone’s sea level pressure minimum developed much more in concert with the development of its associated EKE center. As a consequence, the first cyclone began losing EKE through downstream energy fluxes even as it was developing at the surface, whereas the second cyclone did not disperse EKE downstream until later in its life cycle. Consideration of the EKE budget results in terms of baroclinic wave packets demonstrates that the first cyclone developed and decayed on the upstream edge of a wave packet, whereas the second cyclone developed in the midst of a wave packet, only decaying once it had reached the upstream edge. Thus, it is suggested that postmature phase decay is dynamically linked to a cyclone’s position in a given wave packet.
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Kawashima, Masayuki, and Yasushi Fujiyoshi. "Shear Instability Wave along a Snowband: Instability Structure, Evolution, and Energetics Derived from Dual-Doppler Radar Data." Journal of the Atmospheric Sciences 62, no. 2 (February 1, 2005): 351–70. http://dx.doi.org/10.1175/jas-3392.1.
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Abstract This article presents a detailed analysis of a meso-γ-scale (∼17 km wavelength) shear instability wave along a snowband using a series of dual-Doppler radar data. The wave developed along a low-level shear line that formed under the strain wind field caused by an adjacent mesoscale vortex. The horizontal wind shear across the line was largest at lower levels, and the eddy-component horizontal winds and the retrieved pressure anomaly showed a bottom-intensified structure as well. The resultant vertical pressure gradient force was found to be responsible for the enhancement of alternating updrafts and downdrafts that were subsequently related to the formation of the reflectivity core/gap structure of the wave. Eddy kinetic energy (EKE) budgets of the evolving disturbance were investigated using time series of retrieved kinematic and thermodynamic data. The wave grew at an approximately constant growth rate for about 40 min from its onset. The EKE in this quasi-linear growth period was primarily generated by the horizontal shear that decreased with height. The pressure work was found to remove about two-thirds of this generation in the layer below 1 km, while in the upper layer it was constructive to EKE generation and comparable to the generation of EKE by horizontal shear. These results indicate that the source of EKE was basically located at low levels and the energy was transported upward mainly by the pressure work. After the quasi-linear growth period, horizontal shear generation rapidly decreased and EKE peaked. The buoyancy generation of EKE was small but positive in the quasi-linear growth period, then became negative because of the development of thermally indirect circulations.
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THAYER, ANN M. "MAJOR DRUG FIRMS EKE OUT INCREASES." Chemical & Engineering News 81, no. 11 (March 17, 2003): 13–14. http://dx.doi.org/10.1021/cen-v081n011.p013.
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Barthel, Alice, Andrew McC. Hogg, Stephanie Waterman, and Shane Keating. "Jet–Topography Interactions Affect Energy Pathways to the Deep Southern Ocean." Journal of Physical Oceanography 47, no. 7 (July 2017): 1799–816. http://dx.doi.org/10.1175/jpo-d-16-0220.1.
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AbstractIn the Southern Ocean, strong eastward ocean jets interact with large topographic features, generating eddies that feed back onto the mean flow. Deep-reaching eddies interact with topography, where turbulent dissipation and generation of internal lee waves play an important role in the ocean’s energy budget. However, eddy effects in the deep ocean are difficult to observe and poorly characterized. This study investigates the energy contained in eddies at depth, when an ocean jet encounters topography. This study uses a two-layer ocean model in which an imposed unstable jet encounters a topographic obstacle (either a seamount or a meridional ridge) in a configuration relevant to an Antarctic Circumpolar Current frontal jet. The authors find that the presence of topography increases the eddy kinetic energy (EKE) at depth but that the dominant processes generating this deep EKE depend on the shape and height of the obstacle as well as on the baroclinicity of the jet before it encounters topography. In cases with high topography, horizontal shear instability is the dominant source of deep EKE, while a flat bottom or a strongly sheared inflow leads to deep EKE being generated primarily through baroclinic instability. These results suggest that the deep EKE is set by an interplay between the inflowing jet properties and topography and imply that the response of deep EKE to changes in the Southern Ocean circulation is likely to vary across locations depending on the topography characteristics.
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Rieck, Jan K., Claus W. Böning, and Richard J. Greatbatch. "Decadal Variability of Eddy Kinetic Energy in the South Pacific Subtropical Countercurrent in an Ocean General Circulation Model." Journal of Physical Oceanography 48, no. 4 (April 2018): 757–71. http://dx.doi.org/10.1175/jpo-d-17-0173.1.
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AbstractThe eddy kinetic energy (EKE) associated with the Subtropical Countercurrent (STCC) in the western subtropical South Pacific is known to exhibit substantial seasonal and decadal variability. Using an eddy-permitting ocean general circulation model, which is able to reproduce the observed, salient features of the seasonal cycles of shear, stratification, baroclinic production, and the associated EKE, the authors investigate the decadal changes of EKE. The authors show that the STCC region exhibits, uniquely among the subtropical gyres of the world’s oceans, significant, atmospherically forced, decadal EKE variability. The decadal variations are driven by changing vertical shear between the STCC in the upper 300 m and the South Equatorial Current below, predominantly caused by variations in STCC strength associated with a changing meridional density gradient. In the 1970s, an increased meridional density gradient results in EKE twice as large as in later decades in the model. Utilizing sensitivity experiments, decadal variations in the wind field are shown to be the essential driver. Local wind stress curl anomalies associated with the interdecadal Pacific oscillation (IPO) lead to upwelling and downwelling of the thermocline, inducing strengthening or weakening of the STCC and the associated EKE. Additionally, remote wind stress curl anomalies in the eastern subtropical South Pacific, which are not related to the IPO, generate density anomalies that propagate westward as Rossby waves and can account for up to 30%–40% of the density anomalies in the investigated region.
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Hadorn, David, Giorgi Kvizhinadze, Lucie Collinson, and Tony Blakely. "USEOF EXPERT KNOWLEDGE ELICITATION TO ESTIMATE PARAMETERS IN HEALTH ECONOMIC DECISION MODELS." International Journal of Technology Assessment in Health Care 30, no. 4 (October 2014): 461–68. http://dx.doi.org/10.1017/s0266462314000427.
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Objectives: The aim of this study was to determine the prevalence and methods of expert knowledge elicitation (EKE) for specifying input parameters in health economic decision models (HEDM).Methods: We created two samples using the National Health System Economic Evaluations Database: (1) 100 randomly selected HEDM studies to determine prevalence of EKE and (2) sixty studies using a formal EKE process to determine methods used.Results: Fifty-seven (57 percent) of the random sample included at least one EKE-derived parameter. Of these, six (10 percent) used a formal expert process. Thirty-four studies from our second sample of sixty studies (57 percent) described at least one aspect of the process (e.g., elicitation method) with reasonable clarity. In approximately two-thirds of studies the external experts estimated parameters de novo; the remainder confirmed or modified initial estimates provided by authors, or the method was unclear. The majority of elicitations obtained point estimates only, although a few studies asked experts to estimate ranges of parameter values.Conclusions: The use of EKE for parameter estimation is common in HEDMs, although there is room for improvement in the methods used.
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Yang, Yang, and X. San Liang. "On the Seasonal Eddy Variability in the Kuroshio Extension." Journal of Physical Oceanography 48, no. 8 (August 2018): 1675–89. http://dx.doi.org/10.1175/jpo-d-18-0058.1.
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AbstractUsing a recently developed tool, multiscale window transform (MWT), and the MWT-based canonical energy transfer theory, this study investigates the seasonal eddy variability in the Kuroshio Extension. Distinct seasonal cycles of eddy kinetic energy (EKE) are observed in the upstream and downstream regions of the Kuroshio Extension. In the upstream Kuroshio Extension, the EKE peaks in summer and reaches its minimum in winter over an annual cycle. By diagnosing the spatiotemporal structures of the canonical barotropic and baroclinic energy transfers, we found that internal processes due to mixed instabilities (i.e., both barotropic and baroclinic instabilities) are responsible for the seasonal eddy variability in this region. In the downstream Kuroshio Extension, the EKE exhibits a different annual cycle, peaking in spring and gradually decaying from summer to winter. Significant inverse barotropic energy transfer is found in this region throughout the year, leaving baroclinic instability the primary energy source for the regional seasonal eddy variability. Besides the internal redistribution, it is also evident that the external forcing may influence the Kuroshio Extension EKE seasonality—the EKE is found to be more damped by winds during winter than summer.
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Qiu, Bo, Robert B. Scott, and Shuiming Chen. "Length Scales of Eddy Generation and Nonlinear Evolution of the Seasonally Modulated South Pacific Subtropical Countercurrent." Journal of Physical Oceanography 38, no. 7 (July 1, 2008): 1515–28. http://dx.doi.org/10.1175/2007jpo3856.1.
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Abstract The dynamical processes behind the seasonal modulation of the two-dimensional eddy kinetic energy (EKE) wavenumber spectrum in the Subtropical Countercurrent region of the South Pacific are investigated with 14 yr of satellite altimeter data and climatological hydrographic data. The authors find a seasonally modulated generation of EKE via baroclinic instability in modes with larger meridional length scales. Subsequent nonlinear eddy–eddy interactions redistribute the EKE to larger total horizontal length scales, and larger zonal scales in particular. This is confirmed by diagnosing the spectral transfer of EKE in the surface geostrophic flow, which is found to drive an anisotropic inverse cascade, being redirected in the sense consistent with the β effect, as predicted by geostrophic turbulence theory on the β plane. Because of the seasonal renewal of meridionally elongated anomalies by baroclinic instability and possibly because of the barotropization process, however, the net outcome for the formation of surface zonal flows is observed to be limited.
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Fischer, Jürgen, Johannes Karstensen, Marilena Oltmanns, and Sunke Schmidtko. "Mean circulation and EKE distribution in the Labrador Sea Water level of the subpolar North Atlantic." Ocean Science 14, no. 5 (October 5, 2018): 1167–83. http://dx.doi.org/10.5194/os-14-1167-2018.
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Abstract. A long-term mean flow field for the subpolar North Atlantic region with a horizontal resolution of approximately 25 km is created by gridding Argo-derived velocity vectors using two different topography-following interpolation schemes. The 10-day float displacements in the typical drift depths of 1000 to 1500 m represent the flow in the Labrador Sea Water density range. Both mapping algorithms separate the flow field into potential vorticity (PV) conserving, i.e., topography-following contribution and a deviating part, which we define as the eddy contribution. To verify the significance of the separation, we compare the mean flow and the eddy kinetic energy (EKE), derived from both mapping algorithms, with those obtained from multiyear mooring observations. The PV-conserving mean flow is characterized by stable boundary currents along all major topographic features including shelf breaks and basin-interior topographic ridges such as the Reykjanes Ridge or the Rockall Plateau. Mid-basin northward advection pathways from the northeastern Labrador Sea into the Irminger Sea and from the Mid-Atlantic Ridge region into the Iceland Basin are well-resolved. An eastward flow is present across the southern boundary of the subpolar gyre near 52∘ N, the latitude of the Charlie Gibbs Fracture Zone (CGFZ). The mid-depth EKE field resembles most of the satellite-derived surface EKE field. However, noticeable differences exist along the northward advection pathways in the Irminger Sea and the Iceland Basin, where the deep EKE exceeds the surface EKE field. Further, the ratio between mean flow and the square root of the EKE, the Peclet number, reveals distinct advection-dominated regions as well as basin-interior regimes in which mixing is prevailing.
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Appen, Wilken-Jon von, Ursula Schauer, Tore Hattermann, and Agnieszka Beszczynska-Möller. "Seasonal Cycle of Mesoscale Instability of the West Spitsbergen Current." Journal of Physical Oceanography 46, no. 4 (April 2016): 1231–54. http://dx.doi.org/10.1175/jpo-d-15-0184.1.
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AbstractThe West Spitsbergen Current (WSC) is a topographically steered boundary current that transports warm Atlantic Water northward in Fram Strait. The 16 yr (1997–2012) current and temperature–salinity measurements from moorings in the WSC at 78°50′N reveal the dynamics of mesoscale variability in the WSC and the central Fram Strait. A strong seasonality of the fluctuations and the proposed driving mechanisms is described. In winter, water is advected in the WSC that has been subjected to strong atmospheric cooling in the Nordic Seas, and as a result the stratification in the top 250 m is weak. The current is also stronger than in summer and has a greater vertical shear. This results in an e-folding growth period for baroclinic instabilities of about half a day in winter, indicating that the current has the ability to rapidly grow unstable and form eddies. In summer, the WSC is significantly less unstable with an e-folding growth period of 2 days. Observations of the eddy kinetic energy (EKE) show a peak in the boundary current in January–February when it is most unstable. Eddies are then likely advected westward, and the EKE peak is observed 1–2 months later in the central Fram Strait. Conversely, the EKE in the WSC as well as in the central Fram Strait is reduced by a factor of more than 3 in late summer. Parameterizations for the expected EKE resulting from baroclinic instability can account for the observed EKE values. Hence, mesoscale instability can generate the observed variability, and high-frequency wind forcing is not required to explain the observed EKE.
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Biton, Eli, and Hezi Gildor. "On the Origin of a Chain of Eddies in the Gulf of Eilat/Aqaba." Journal of Physical Oceanography 46, no. 8 (August 2016): 2269–84. http://dx.doi.org/10.1175/jpo-d-15-0208.1.
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AbstractThe Gulf of Eilat/Aqaba is a terminal, elongated basin that exchanges water with the northern Red Sea via the Straits of Tiran. This study used energy budgets of mean kinetic energy (MKE) and eddy kinetic energy (EKE; differentiated by a simple horizontal averaging filter), instability analysis, and numerical simulations to study the horizontal circulation of the gulf, which is characterized by the existence of a chain of eddies along its main axis. The kinetic energy is predominantly in the form of EKE. Energy conversion between MKE and EKE is negligible where the main sources for both energy reservoirs are the conversions from the available potential energy (APE). This term is balanced by the work done by pressure at the straits in case of MKE and by dissipation in the case of EKE. The MKE balance represents the coupling between the exchange flow at the straits and the wintertime dense water formation. The dense water exits through the straits while sinking adiabatically along the gulf. The strong variation in the shoreline/bathymetry triggers a baroclinic instability that enhances the eddy activity in the gulf. Thus, the baroclinic instability is an effective mechanism that transfers energy from the APE to the EKE. The EKE–APE conversion term involves vertical adiabatic motions that occur through the upwelling of relatively warm water in anticyclonic circulation regions and downwelling of colder water in adjacent regions with cyclonic circulation. Through these processes, the horizontal circulation is powered by the energy transferred from the APE. This explains the coupling between the temperature gradient and the eddy formation along the gulf.
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Kang, Dujuan, Enrique N. Curchitser, and Anthony Rosati. "Seasonal Variability of the Gulf Stream Kinetic Energy." Journal of Physical Oceanography 46, no. 4 (April 2016): 1189–207. http://dx.doi.org/10.1175/jpo-d-15-0235.1.
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AbstractThe seasonal variability of the mean kinetic energy (MKE) and eddy kinetic energy (EKE) of the Gulf Stream (GS) is examined using high-resolution regional ocean model simulations. A set of three numerical experiments with different surface wind and buoyancy forcing is analyzed to investigate the mechanisms governing the seasonal cycle of upper ocean energetics. In the GS along-coast region, MKE has a significant seasonal cycle that peaks in summer, while EKE has two comparable peaks in May and September near the surface; the May peak decays rapidly with depth. In the off-coast region, MKE has a weak seasonal cycle that peaks in summer, while EKE has a dominant peak in May and a secondary peak in September near the surface. The May peak also decays with depth leaving the September peak as the only seasonal signal below 100 m. An analysis of the three numerical experiments suggests that the seasonal variability in the local wind forcing significantly impacts the September peak of the along-coast EKE through a local-flow barotropic instability process. Alternatively, the seasonal buoyancy forcing primarily impacts the flow baroclinic instability and is consequently related to the May peak of the upper ocean EKE in both regions. The analysis results indicate that the seasonal cycle of the along-coast MKE is influenced by both local energy generation by wind and the advection of energy from upstream regions. Finally, the MKE cycle and the September peak of EKE in the off-coast region are mainly affected by advection of energy from remote regions, giving rise to correlations with the seasonal cycle of remote winds.
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Puača, Gorana, Nemanja Todorović, Jelena Čanji, Dejana Bajić, Dunja Vesković, Nebojša Pavlović, Snježana Ilić, and Mladena Lalić-Popović. "Exposure of children in Serbia to potentially harmful excipients when treated with approved antibiotics." Hospital Pharmacology - International Multidisciplinary Journal 8, no. 1 (2021): 1014–25. http://dx.doi.org/10.5937/hpimj2101014p.
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Introduction: According to current understanding of the role of excipient in medicines, they could not be considered as completely pharmacologically inert substances. Although excipients do not have the potential to cause adverse drug reactions (ADRs) in most patients, some of their negative effects have been established. Special caution regarding excipients intake is advised, especially in vulnerable populations such as pediatric one. Aim: The aim of this paper was to investigate the exposure of children on antibiotic therapy to excipients with known effects (EKE). Methods: During a one-month period antibiotic prescriptions data were taken from community pharmacies in Novi Sad, Serbia. Age, diagnosis and prescribed therapy were observed. Data about qualitative content of prescribed medicines were taken from Summaries of Product Characteristics (SmPC) available at the official website of Medicines and medical devices agency of Serbia (ALIMS). Excipients were considered to be potentially harmful if they were listed in European Medicines Agency (EMA) guidelines. Results: The most commonly observed diagnosis was a respiratory infection, which affected more than 88% of children prescribed with an antibiotic. Only 5 out of 33 prescribed antibiotic formulations did not contain at least one EKE. Prescribed medicines mostly contained sodium compounds (77.78%), sucrose (34.07%) and sodium benzoate (31.11%). In addition, the following EKE were detected: propylene glycol, aspartame, sorbitol, lactose, potassium, mannitol, benzalkonium chloride, azorubine, parabens, sodium metabisulfite and sunset yellow. Around 75% of prescribed antibiotic formulations contained inappropriately labeled EKE (sodium and potassium compounds, sodium benzoate and propylene glycol). Additionally, inappropriately labeled information leaflets did not include possible adverse effects caused by the EKE. Conclusions: This paper indicates high exposure of patients to EKE, where almost all children treated with antibiotics (96.3%) were simultaneously administered at least one EKE. We confirmed that approved medicines cannot meet the treatment needs of all patients, and that inappropriately labeled medicines carry a risk of ADRs, especially in newborns. Personalized treatment is especially important in children, as the appropriate dosage forms and diversity in formulation ingredients is lacking. Knowing the type and roles of each ingredient of the medicines it is possible to formulate a preparation that will meet all the individual children's needs.
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Waugh, Darryn W., Edward R. Abraham, and Melissa M. Bowen. "Spatial Variations of Stirring in the Surface Ocean: A Case Study of the Tasman Sea." Journal of Physical Oceanography 36, no. 3 (March 1, 2006): 526–42. http://dx.doi.org/10.1175/jpo2865.1.
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Abstract Stirring in the Tasman Sea is examined using surface geostrophic currents derived from satellite altimeter measurements. Calculations of the distribution of finite-time Lyapunov exponents (FTLEs) indicate that the stirring in this region is not uniform and stretching rates over 15 days vary from less than 0.02 day−1 to over 0.3 day−1. These variations occur at both small (∼10 km) and large (∼1000 km) scales and in both cases are linked to dynamical features of the flow. The small-scale variations are related to the characteristics of coherent vortex structures, and there are low FTLEs inside vortices and filaments of high FTLEs in strain-dominated regions surrounding these vortices. Regional variations in the stirring are closely related to variations in mesoscale activity and eddy kinetic energy (EKE). High values of mean FTLE occur in regions of high EKE (highest mean values of around 0.2 day−1 occur in the East Australia Current separation region) whereas small values occur in regions with low EKE (mean values around 0.03 day−1 in the east Tasman Sea). There is a compact relationship between the mean FTLEs and EKE, raising the possibility of using the easily calculated EKE to estimate the stirring. This possibility is even more intriguing because the FTLE distributions can be approximated, for the time scales considered here, by Weibull distributions with shape parameter equal to 1.6, which can be defined from the mean value alone.
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Kang, Dujuan, and Enrique N. Curchitser. "On the Evaluation of Seasonal Variability of the Ocean Kinetic Energy." Journal of Physical Oceanography 47, no. 7 (July 2017): 1675–83. http://dx.doi.org/10.1175/jpo-d-17-0063.1.
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AbstractThe seasonal cycles of the mean kinetic energy (MKE) and eddy kinetic energy (EKE) are compared in an idealized flow as well as in a realistic simulation of the Gulf Stream (GS) region based on three commonly used definitions: orthogonal, nonorthogonal, and moving-average filtered decompositions of the kinetic energy (KE). It is shown that only the orthogonal KE decomposition can define the physically consistent MKE and EKE that precisely represents the KEs of the mean flow and eddies, respectively. The nonorthogonal KE decomposition gives rise to a residual term that contributes to the seasonal variability of the eddies, and therefore the obtained EKE is not precisely defined. The residual term is shown to exhibit more significant seasonal variability than EKE in both idealized and realistic GS flows. Neglecting its influence leads to an inaccurate evaluation of the seasonal variability of both the eddies and the total flow. The decomposition using a moving-average filter also results in a nonnegligible residual term in both idealized and realistic GS flows. This type of definition does not ensure conservation of the total KE, even if taking into account the residual term. Moreover, it is shown that the annual cycles of the three types of EKEs or MKEs have different phases and amplitudes. The local differences of the EKE cycles are very prominent in the GS off-coast domain; however, because of the spatial inhomogeneity, the area-mean differences may not be significant.
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Cai, Zhongya, and Jianping Gan. "Dynamics of the Layered Circulation Inferred from Kinetic Energy Pathway in the South China Sea." Journal of Physical Oceanography 51, no. 5 (May 2021): 1671–85. http://dx.doi.org/10.1175/jpo-d-20-0226.1.
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AbstractWe investigated the mean kinetic energy (MKE) and eddy kinetic energy (EKE) in the South China Sea to illustrate the dynamics of the vertically rotating cyclonic–anticyclonic–cyclonic (CAC) circulation in the upper, middle, and deep layers. We found that strong MKE along the basin slope and the associated EKE arising from the vertical shear and stratification of the mean current characterize the circulation. In the upper layer, the external MKE input from the Kuroshio intrusion and wind forcing drive the cyclonic circulation, with the wind forcing providing most of the EKE. External forcing, however, does not directly provide the MKE and EKE of the CAC circulation in the semi-enclosed middle and deep layers, where the internal pressure work near Luzon Strait and the vertical buoyancy flux (VBF) in the southern basin and along the western slope maintain the MKE and EKE. The internal pressure work is formed by ageostrophic motion and pressure gradient field associated with circulation. The VBF is generated by vertical motion induced by the geostrophic cross-isobath transport along the slope where variable density field is maintained by the external flow and the internal mixing. The kinetic energy pathway in the CAC circulation indicates that the external forcing dominates upper-layer circulation and the coupling between internal and external dynamics is crucial for maintaining the circulation in the middle and deep layers. This study provides a new interpretation to the maintenance of CAC circulation from energy prospect.
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Klausnitzer, Ralf. "Alo Allkemper / Norbert Otto Eke, Literaturwissenschaft. 2004." Arbitrium 24, no. 1 (January 4, 2006): 1–7. http://dx.doi.org/10.1515/arbi.2006.1.
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Allen, Pam. "Norbert Eke: Heiner Müller. Apokalypse und Utopie." GDR Bulletin 16, no. 2 (October 17, 1990): 32. http://dx.doi.org/10.4148/gdrb.v16i2.968.
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Peng, Shiqiu, Yu-Kun Qian, Rick Lumpkin, Yan Du, Dongxiao Wang, and Ping Li. "Characteristics of the Near-Surface Currents in the Indian Ocean as Deduced from Satellite-Tracked Surface Drifters. Part I: Pseudo-Eulerian Statistics." Journal of Physical Oceanography 45, no. 2 (February 2015): 441–58. http://dx.doi.org/10.1175/jpo-d-14-0050.1.
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AbstractUsing the 1985–2013 record of near-surface currents from satellite-tracked drifters, the pseudo-Eulerian statistics of the near-surface circulation in the Indian Ocean (IO) are analyzed. It is found that the distributions of the current velocities and mean kinetic energy (MKE) in the IO are extremely inhomogeneous in space and nonstationary in time. The most energetic regions with climatologic mean velocity over 50 cm s−1 and MKE over 500 cm2 s−2 are found off the eastern coast of Somalia (with maxima of over 100 cm s−1 and 1500 cm2 s−2) and the equatorial IO, associated with the strong, annually reversing Somalia Current and the twice-a-year eastward equatorial jets. High eddy kinetic energy (EKE) is found in regions of the equatorial IO, western boundary currents, and Agulhas Return Current, with a maximum of over 3000 cm2 s−2 off the eastern coast of Somalia. The lowest EKE (<500 cm2 s−2) occurs in the south subtropical gyre between 30° and 40°S and the central-eastern Arabian Sea. Annual and semiannual variability is a significant fraction of the total EKE off the eastern coast of Somalia and in the central-eastern equatorial IO. In general, both the MKE and EKE estimated in the present study are qualitatively in agreement with, but quantitatively larger than, estimates from previous studies. These pseudo-Eulerian MKE and EKE fields, based on the most extensive drifter dataset to date, are the most precise in situ estimates to date and can be used to validate satellite and numerical results.
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Jouanno, Julien, Julio Sheinbaum, Bernard Barnier, Jean Marc Molines, and Julio Candela. "Seasonal and Interannual Modulation of the Eddy Kinetic Energy in the Caribbean Sea." Journal of Physical Oceanography 42, no. 11 (November 1, 2012): 2041–55. http://dx.doi.org/10.1175/jpo-d-12-048.1.
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Abstract Variability of the mesoscale eddy field in the Caribbean Sea is analyzed over the period 1993–2009 using geostrophic anomalies derived from altimeter data and a high-resolution regional model. The Colombia Basin presents the largest values of eddy kinetic energy (EKE) and its semiannual cycle, with a main peak in August–October and a secondary peak in February–March, is the dominant feature in the whole Caribbean EKE cycle. The analysis of energy conversion terms between low-frequency currents and eddies explains these peaks by enhanced baroclinic and barotropic instabilities, in response to seasonally varying currents in the region of the Guajira Peninsula. The semiannual acceleration of the atmospheric Caribbean low-level jet intensifies the southern Caribbean Current (sCC) twice a year in this region, together with its vertical and horizontal velocity shears. The asymmetry of the EKE seasonal cycle in the Colombia Basin is explained by a summer peak in the annual cycle of the whole sCC. Numerical results suggest that the arrival of more energetic North Brazil Current rings during part of the year have almost no impact on the seasonal cycle of EKE in the Colombia Basin. Instead, they are shown to contribute, together with the annual cycle of the Caribbean inflow through the southern passages of the Lesser Antilles, to an annual peak of EKE in the Venezuela Basin between May and August. At the interannual scale the mechanism is similar: interannual variability of the alongshore wind stress controls the speed of the southern Caribbean Current and the energy of the eddies in the Colombia Basin through instability.
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Shang, Xiao-dong, Hai-bin Zhu, Gui-ying Chen, Chi Xu, and Qi Yang. "Research on Cold Core Eddy Change and Phytoplankton Bloom Induced by Typhoons: Case Studies in the South China Sea." Advances in Meteorology 2015 (2015): 1–19. http://dx.doi.org/10.1155/2015/340432.
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The effects of 8 typhoons which passed by coldcore eddy (CCE) areas in the South China Sea (SCS) from 1997 to 2009 were observed and evaluated. The changes in the preexisting CCE acted upon by typhoons were described by eddy kinetic energy (EKE) and eddy available gravitational potential energy (EAGPE). The mechanical energy of CCE was estimated from a two-layer reduced gravity model. Comparing with the scenario that typhoon passes by the region without CCEs, the preexisting CCE area plays an important role in the increase of chlorophyll-a (chl-a) concentration in the CCEs impacted by the typhoons. The preexisting chl-a in CCE is about 25%~45% (8%~25%) of postexisting chl-a in CCE for higher (slower) transit speed typhoons. If the EAGPE of CCE increases greatly after typhoon passing by with slow transit speed, so does the chl-a in the CCE area. The EKE (EAGPE) changes of the preexisting CCE are in the order of O(1014~1015 J). EKE and EAGPE of CCE are dominantly enhanced by typhoon with slow transit speed (<3 m/s) and the posttyphoon EAGPE is always larger than posttyphoon EKE for 8 cases. The maximum EAGPE change of the preexisting CCE reaches5.11×1015 J, which was induced by typhoon Hagibis.
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Chang, Y. L., and L. Y. Oey. "Instability of the North Pacific Subtropical Countercurrent." Journal of Physical Oceanography 44, no. 3 (March 1, 2014): 818–33. http://dx.doi.org/10.1175/jpo-d-13-0162.1.
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Abstract The North Pacific Subtropical Countercurrent (STCC) has a weak eastward velocity near the surface, but the region is populated with eddies. Studies have shown that the STCC is baroclinically unstable with a peak growth rate of 0.015 day−1 in March, and the ~60-day growth time has been used to explain the peak eddy kinetic energy (EKE) in May observed from satellites. It is argued here that this growth time from previously published normal-mode instability analyses is too slow. Growth rates calculated from an initial-value problem without the normal-mode assumption are found to be 1.5 to 2 times faster and at shorter wavelengths, due to the existence of (i) nonmodal solutions and (ii) sea surface temperature front in the mixed layer in winter. At interannual time scales it is shown that because of rapid surface adjustments, the STCC geostrophic shear, hence also the instability growth, is approximately in phase with surface forcing, leading to EKE modulation that peaks approximately 10 months later. However, the EKE can only be partially explained by this mechanism of modulation by baroclinic instability. It is suggested that the unexplained variance may be caused additionally by modulation of the EKE by dissipation.
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Jia, Fan, Lixin Wu, and Bo Qiu. "Seasonal Modulation of Eddy Kinetic Energy and Its Formation Mechanism in the Southeast Indian Ocean." Journal of Physical Oceanography 41, no. 4 (April 1, 2011): 657–65. http://dx.doi.org/10.1175/2010jpo4436.1.
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Abstract Mesoscale eddy activity in the southeast Indian Ocean (15°–30°S, 60°–110°E) is investigated based on available satellite altimetry observations. The observed sea level anomaly data show that this region is the only eastern basin among the global oceans where strong eddy activity exists. Furthermore, the eddy kinetic energy (EKE) level in this region displays a distinct seasonal cycle with the maximum in austral summer and minimum in austral winter. It is found that this seasonal modulation of EKE is mediated by baroclinic instability associated with the surface-intensified South Indian Countercurrent (SICC) and the underlying South Equatorial Current (SEC) system. In austral spring and summer the enhanced flux forcing of combined meridional Ekman and geostrophic convergence strengthens the upper-ocean meridional temperature gradient, intensifying the SICC front and its vertical velocity shear. Modulation of the vertical velocity shear results in the seasonal changes in the strength of baroclinic instability, leading to the seasonal EKE variations in the southeast Indian Ocean.
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Hamilton, Peter, Amy Bower, Heather Furey, Robert Leben, and Paula Pérez-Brunius. "The Loop Current: Observations of Deep Eddies and Topographic Waves." Journal of Physical Oceanography 49, no. 6 (June 2019): 1463–83. http://dx.doi.org/10.1175/jpo-d-18-0213.1.
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AbstractA set of float trajectories, deployed at 1500- and 2500-m depths throughout the deep Gulf of Mexico from 2011 to 2015, are analyzed for mesoscale processes under the Loop Current (LC). In the eastern basin, December 2012–June 2014 had >40 floats per month, which was of sufficient density to allow capturing detailed flow patterns of deep eddies and topographic Rossby waves (TRWs), while two LC eddies formed and separated. A northward advance of the LC front compresses the lower water column and generates an anticyclone. For an extended LC, baroclinic instability eddies (of both signs) develop under the southward-propagating large-scale meanders of the upper-layer jet, resulting in a transfer of eddy kinetic energy (EKE) to the lower layer. The increase in lower-layer EKE occurs only over a few months during meander activity and LC eddy detachment events, a relatively short interval compared with the LC intrusion cycle. Deep EKE of these eddies is dispersed to the west and northwest through radiating TRWs, of which examples were found to the west of the LC. Because of this radiation of EKE, the lower layer of the eastern basin becomes relatively quiescent, particularly in the northeastern basin, when the LC is retracted and a LC eddy has departed. A mean west-to-east, anticyclone–cyclone dipole flow under a mean LC was directly comparable to similar results from a previous moored LC array and also showed connections to an anticlockwise boundary current in the southeastern basin.
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Schemm, Sebastian, and Tapio Schneider. "Eddy Lifetime, Number, and Diffusivity and the Suppression of Eddy Kinetic Energy in Midwinter." Journal of Climate 31, no. 14 (June 22, 2018): 5649–65. http://dx.doi.org/10.1175/jcli-d-17-0644.1.
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Abstract The wintertime evolution of the North Pacific storm track appears to challenge classical theories of baroclinic instability, which predict deeper extratropical cyclones when baroclinicity is highest. Although the surface baroclinicity peaks during midwinter, and the jet is strongest, eddy kinetic energy (EKE) and baroclinic conversion rates have a midwinter minimum over the North Pacific. This study investigates how the reduction in EKE translates into a reduction in eddy potential vorticity (PV) and heat fluxes via changes in eddy diffusivity. Additionally, it augments previous observations of the midwinter storm-track evolution in both hemispheres using climatologies of tracked surface cyclones. In the North Pacific, the number of surface cyclones is highest during midwinter, while the mean EKE per cyclone and the eddy lifetime are reduced. The midwinter reduction in upper-level eddy activity hence is not associated with a reduction in surface cyclone numbers. North Pacific eddy diffusivities exhibit a midwinter reduction at upper levels, where the Lagrangian decorrelation time is shortest (consistent with reduced eddy lifetimes) and the meridional parcel velocity variance is reduced (consistent with reduced EKE). The resulting midwinter reduction in North Pacific eddy diffusivities translates into an eddy PV flux suppression. In contrast, in the North Atlantic, a milder reduction in the decorrelation time is offset by a maximum in velocity variance, preventing a midwinter diffusivity minimum. The results suggest that a focus on causes of the wintertime evolution of Lagrangian decorrelation times and parcel velocity variance will be fruitful for understanding causes of seasonal storm-track variations.
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Barkan, Roy, Kraig B. Winters, and Stefan G. Llewellyn Smith. "Energy Cascades and Loss of Balance in a Reentrant Channel Forced by Wind Stress and Buoyancy Fluxes." Journal of Physical Oceanography 45, no. 1 (January 2015): 272–93. http://dx.doi.org/10.1175/jpo-d-14-0068.1.
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AbstractA large fraction of the kinetic energy in the ocean is stored in the “quasigeostrophic” eddy field. This “balanced” eddy field is expected, according to geostrophic turbulence theory, to transfer energy to larger scales. In order for the general circulation to remain approximately steady, instability mechanisms leading to loss of balance (LOB) have been hypothesized to take place so that the eddy kinetic energy (EKE) may be transferred to small scales where it can be dissipated. This study examines the kinetic energy pathways in fully resolved direct numerical simulations of flow in a flat-bottomed reentrant channel, externally forced by surface buoyancy fluxes and wind stress in a configuration that resembles the Antarctic Circumpolar Current. The flow is allowed to reach a statistical steady state at which point it exhibits both a forward and an inverse energy cascade. Flow interactions with irregular bathymetry are excluded so that bottom drag is the sole mechanism available to dissipate the upscale EKE transfer. The authors show that EKE is dissipated preferentially at small scales near the surface via frontal instabilities associated with LOB and a forward energy cascade rather than by bottom drag after an inverse energy cascade. This is true both with and without forcing by the wind. These results suggest that LOB caused by frontal instabilities near the ocean surface could provide an efficient mechanism, independent of boundary effects, by which EKE is dissipated. Ageostrophic anticyclonic instability is the dominant frontal instability mechanism in these simulations. Symmetric instability is also important in a “deep convection” region, where it can be sustained by buoyancy loss.
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Sinha, Anirban, and Ryan P. Abernathey. "Time Scales of Southern Ocean Eddy Equilibration." Journal of Physical Oceanography 46, no. 9 (September 2016): 2785–805. http://dx.doi.org/10.1175/jpo-d-16-0041.1.
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AbstractStratification in the Southern Ocean is determined primarily by a competition between westerly wind-driven upwelling and baroclinic eddy transport. This study investigates the time scales of equilibration of the Southern Ocean in response to changing winds through an idealized channel model. An analytical framework describing the energetic pathways between wind input, available potential energy (APE), eddy kinetic energy (EKE), and dissipation provides a simple theory of the phase and amplitude response to oscillating wind stress. The transient ocean response to variable winds lies between the two limits of Ekman response (high frequency), characterized by the isopycnal slope responding directly to wind stress, and “eddy saturation” (low frequency), wherein a large fraction of the anomalous wind work goes into mesoscale eddies. The crossover time scale is the time scale of meridional eddy diffusive transport across the Antarctic Circumpolar Current (ACC) front. For wind variability with a period of 3 months (high-frequency forcing), the relative conversion of wind work to APE/EKE is 11, while for a period of 16 years (low-frequency forcing), the relative conversion to APE/EKE reduces to 3. The system’s frequency response is characterized by a complex transfer function. Both the phase and amplitude response of EKE and APE predicted by the linear analytic framework are verified using multiple ensemble experiments in an eddy-resolving (4-km horizontal resolution) isopycnal coordinate model. The results from the numerical experiments show agreement with the linear theory and can be used to explain certain features observed in previous modeling studies and observations.
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Rivière, Gwendal, Jean-Baptiste Gilet, and Ludivine Oruba. "Understanding the Regeneration Stage Undergone by Surface Cyclones Crossing a Midlatitude Jet in a Two-Layer Model." Journal of the Atmospheric Sciences 70, no. 9 (September 1, 2013): 2832–53. http://dx.doi.org/10.1175/jas-d-12-0345.1.
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Abstract The present paper provides a rationale for the regeneration stage undergone by surface cyclones when they cross a baroclinic jet from its anticyclonic-shear (warm) side to its cyclonic-shear (cold) side in a two-layer quasigeostrophic model. To do so, the evolution of finite-amplitude synoptic cyclones in various baroclinic zonal flows is analyzed. Baroclinic zonal flows with uniform horizontal shears are first considered. While the anticyclonic shear allows a much more efficient and sustainable extraction of potential energy than the cyclonic shear, the growth of the lower-layer eddy kinetic energy (EKE) is shown to be highly dependent on the choice of the parameter values. An increased vertical shear leads to a more rapid EKE increase in the anticyclonic shear than in the cyclonic shear whereas increasing the vertically averaged potential vorticity gradient or the barotropic shear stabilizes the EKE more in the former shear than in the latter. Finally, vertical velocities arising from the nonlinear interaction between synoptic cyclones are shown to favor EKE growth in the cyclonic shear rather than in the anticyclonic one. The evolution of cyclones initialized on the warm side of a meridionally confined baroclinic jet is then investigated. The lower-layer cyclone crosses the jet axis and undergoes two distinct growth stages. The first growth stage results from the classical baroclinic interaction and is mainly driven by linear interaction between the cyclones and the jet. The second growth stage is mainly a nonlinear process. It is triggered by the vertical velocities created by the three-dimensional structure of the cyclonic disturbances when they reach the cyclonic side of the jet.
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Nino, Valentina, David Claudio, Leonardo Valladares, and Sean Harris. "An Enhanced Kaizen Event in a Sterile Processing Department of a Rural Hospital: A Case Study." International Journal of Environmental Research and Public Health 17, no. 23 (November 25, 2020): 8748. http://dx.doi.org/10.3390/ijerph17238748.
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Operating Rooms (ORs) generate the largest revenues and losses in a hospital. Without the prompt supply of sterile surgical trays from the Sterile Processing Department (SPD), the OR would not be able to perform surgeries to its busy schedule. Nevertheless, little emphasis has been brought in the medical literature to research on surgical instrument processing in the medical literature. The present study was done applies an Enhanced Kaizen Event (EKE) in the SPD of a rural hospital to identify sources of waste and minimize non-value-added steps in the SPD processes. The EKE consisted of three successive Plan-Do-Check-Act (PDCA) cycles, which focused on improvements at the departmental level first, then at an area level, and finally at the station level. The EKE yielded an improved streamlined workflow and a new design for the SPD layout, one of its areas, and a workstation. This paper aims at building a methodology, including identified steps. Results exhibited a 35% reduction in travel distance by the staff, eliminating non-value-added processes, reducing errors in the sterilization process, and eliminating cross-contamination for sterilized materials.
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Bischoff, Tobias, and Andrew F. Thompson. "Configuration of a Southern Ocean Storm Track." Journal of Physical Oceanography 44, no. 12 (November 26, 2014): 3072–78. http://dx.doi.org/10.1175/jpo-d-14-0062.1.
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Abstract Diagnostics of ocean variability that reflect and influence local transport properties of heat and chemical species vary by an order of magnitude along the Southern Ocean’s Antarctic Circumpolar Current (ACC). Topographic “hotspots” are important regions of localized transport anomalies. This study uses a primitive equation channel model to investigate the structure of eddy kinetic energy (EKE), one measure of variability, in an oceanic regime. A storm-track approach emphasizes the importance of stationary eddies, which result from flow interactions with topography, on setting EKE distributions. The influence of these interactions extends far downstream of the topography and impacts EKE patterns through localized convergence and divergence of heat. Unlike for zonal averages, local contributions to the stationary fluxes from terms that integrate to zero in a zonal average are important. The simulations show a strong sensitivity of the zonal structure as well as the distribution and amplitude of stationary eddy fluxes to the surface wind forcing. By focusing on local, time-averaged stationary eddy fluxes, insight into the dynamical structure of the ACC can be gained that is concealed in the averaging procedure associated with traditional zonal or along-stream analyses.
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Catak, Muammer. "Car license plate recognition based on EKE-poisson transform." Journal of Intelligent & Fuzzy Systems 27, no. 4 (2014): 2023–28. http://dx.doi.org/10.3233/ifs-141168.
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Qian, Pengjiang, Chen Xi, Min Xu, Yizhang Jiang, Kuan-Hao Su, Shitong Wang, and Raymond F. Muzic. "SSC-EKE: Semi-supervised classification with extensive knowledge exploitation." Information Sciences 422 (January 2018): 51–76. http://dx.doi.org/10.1016/j.ins.2017.08.093.
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Brophy, James M. "Norbert Otto Eke (Hrsg.), Vormärz-Handbuch. Bielefeld, Aisthesis 2020." Historische Zeitschrift 313, no. 1 (August 1, 2021): 242–44. http://dx.doi.org/10.1515/hzhz-2021-1268.
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Seiki, Ayako, and Yukari N. Takayabu. "Westerly Wind Bursts and Their Relationship with Intraseasonal Variations and ENSO. Part II: Energetics over the Western and Central Pacific." Monthly Weather Review 135, no. 10 (October 1, 2007): 3346–61. http://dx.doi.org/10.1175/mwr3503.1.
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Abstract The mechanism of synoptic-scale eddy development in the generation of westerly wind bursts (WWBs) over the western–central Pacific, and their relationship with the El Niño–Southern Oscillation (ENSO) and the Madden–Julian oscillation (MJO), were examined. In the WWB occurrences, barotropic structures of equatorial eddy westerlies with cyclonic disturbances were found from the surface to the upper troposphere. The dominant contributions to substantial eddy kinetic energy (EKE) were the barotropic energy conversion (KmKe) in the lower and middle tropospheres and the conversion from eddy available potential energy (PeKe) in the upper troposphere. Low-frequency environmental westerlies centered near the equator preceded strong zonal convergence and meridional shear, resulting in the substantial KmKe. The activation of synoptic convection also contributed to an increase in EKE through PeKe. These energies were redistributed to the lower-equatorial troposphere through energy flux convergence (GKe). These results showed that environmental fields contribute to the EKE increase near the equator and are important factors in WWB occurrences. Next, eddy growth was compared under different phases of MJO and ENSO. The MJO westerly phases of strong MJO events were classified into two groups, in terms of ENSO phases. Higher EKE values were found over the equatorial central Pacific in the WWB–ENSO correlated (pre–El Niño) periods. The energetics during these periods comported with those of the WWB generations. In the uncorrelated periods, the enhancement of eddy disturbances occurred far from the equator near the Philippines, where the activities of the easterly wave disturbances are well known. It is noteworthy that the enhanced region of the disturbances in the pre–El Niño periods coincided with the vicinity of large-scale MJO convection. It is suggested that coincidence corresponds with an enhancement of the internal disturbances embedded in the MJO, which is found only when the environmental conditions are favorable in association with ENSO.
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He, Chunbo, Junbin Gong, Lixia Yang, Hongwei Zhang, Shouliang Dong, and Lanxia Zhou. "Pain regulation of endokinin A/B or endokinin C/D on chimeric peptide MCRT in mice." Canadian Journal of Physiology and Pharmacology 94, no. 9 (September 2016): 955–60. http://dx.doi.org/10.1139/cjpp-2015-0554.
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The present study focused on the interactive pain regulation of endokinin A/B (EKA/B, the common C-terminal decapeptide in EKA and EKB) or endokinin C/D (EKC/D, the common C-terminal duodecapeptide in EKC and EKD) on chimeric peptide MCRT (YPFPFRTic-NH2, based on YPFP-NH2 and PFRTic-NH2) at the supraspinal level in mice. Results demonstrated that the co-injection of nanomolar EKA/B and MCRT showed moderate regulation, whereas 30 pmol EKA/B had no effect on MCRT. The combination of EKC/D and MCRT produced enhanced antinociception, which was nearly equal to the sum of the mathematical values of single EKC/D and MCRT. Mechanism studies revealed that pre-injected naloxone attenuated the combination significantly compared with the equivalent analgesic effects of EKC/D alone, suggesting that EKC/D and MCRT might act on two totally independent pathways. Moreover, based on the above results and previous reports, we made two reasonable hypotheses to explain the cocktail-induced analgesia, which may potentially pave the way to explore the respective regulatory mechanisms of EKA/B, EKC/D, and MCRT and to better understand the complicated pain regulation of NK1 and μ opioid receptors, as follows: (1) MCRT and endomorphin-1 possibly activated different μ subtypes; and (2) picomolar EKA/B might motivate the endogenous NPFF system after NK1 activation.
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Wang, Minyang, Yan Du, Bo Qiu, Shang-Ping Xie, and Ming Feng. "Dynamics on Seasonal Variability of EKE Associated with TIWs in the Eastern Equatorial Pacific Ocean." Journal of Physical Oceanography 49, no. 6 (June 2019): 1503–19. http://dx.doi.org/10.1175/jpo-d-18-0163.1.
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AbstractEnergetic mesoscale eddies (vortices) associated with tropical instability waves (TIWs) exist in the eastern equatorial Pacific Ocean between 0° and 8°N. This study examines the seasonal variations in eddy kinetic energy (EKE) of TIWs using in situ and satellite observations and elucidates the underlying dynamical mechanisms. The results reveal that the cross-equatorial southerly winds are key to sustaining the high-level EKE (up to ~600 cm2 s−2) from boreal summer to winter in 0°–6°N and 155°–110°W. Because of the β effect and the surface wind divergence, the southerly winds generate anticyclonic wind curls north of the equator that intensify the sea surface temperature (SST) fronts and force the downwelling annual Rossby waves. The resultant sea surface height ridge induces strong horizontal current shears between 0° and 5°N. The intensified current shears and SST fronts generate EKE via barotropic and baroclinic instabilities, respectively. To the extent that the seasonal migration of a northward-displaced intertropical convergence zone intensifies the southerly winds north of, but not south of, the equator, our study suggests that the climatic asymmetry is important for the oceanic eddy generations in the eastern equatorial Pacific Ocean—a result with important implications for coupled climate simulation/prediction.
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Sasaki, Hideharu, and Patrice Klein. "SSH Wavenumber Spectra in the North Pacific from a High-Resolution Realistic Simulation." Journal of Physical Oceanography 42, no. 7 (July 1, 2012): 1233–41. http://dx.doi.org/10.1175/jpo-d-11-0180.1.
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Abstract Following recent studies based on altimetric data, this paper analyses the spectral characteristics of the sea surface height (SSH) using a new realistic simulation of the North Pacific Ocean with high resolution ( in the horizontal and 100 vertical levels). This simulation resolves smaller scales (down to ≈10 km) than altimetric data (limited to 70 km because of the noise level). In high eddy kinetic energy (EKE) regions (as in the western part), SSH spectral slope almost follows a k−4 (with k the wavenumber) or slightly steeper law in agreement with altimeter studies. The new result is that, unlike altimeter studies, such a k−4 slope is also observed in low EKE regions (as in the eastern part). In these regions, this slope mostly concerns scales not well resolved by altimetric data. Such k−4 SSH spectral slopes are weaker from what is expected from quasigeostrophic turbulence theory but closer to surface quasigeostrophic (SQG) turbulence theory. The consequence is that the small scales concerned by these spectral slopes, in particular in low EKE regions, may significantly affect the larger ones because of the inverse kinetic energy cascade. These results need to be confirmed using a longer numerical integration. They also need to be corroborated by high-resolution observations.