Division of Ocean Sciences

DIssolVeD oRgaNIc MatteR IN the oceaN a coNtRoVeRsy stIMulates New INsIghts abstR act. Containing as much carbon as the atmosphere, marine dissolved organic matter is one of Earth's major carbon reservoirs. With invigoration of scientific inquiries into the global carbon cycle, our ignorance of its role in ocean biogeochemistry became untenable. Rapid mobilization of relevant research two decades ago required the community to overcome early false leads, but subsequent progress in examining the global dynamics of this material has been steady. Continuous improvements in analytical skill coupled with global ocean hydrographic survey opportunities resulted in the generation of thousands of measurements throughout the major ocean basins. Here, observations and model results provide new insights into the large-scale variability of dissolved organic carbon, its contribution to the biological pump, and its deep ocean sinks.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolal volumes of electrolytesFrank J. MilleroCite this: Chem. Rev. 1971, 71, 2, 147–176Publication Date (Print):April 1, 1971Publication History Published online1 May 2002Published inissue 1 April 1971https://pubs.acs.org/doi/10.1021/cr60270a001https://doi.org/10.1021/cr60270a001research-articleACS PublicationsRequest reuse permissionsArticle Views2280Altmetric-Citations776LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTViscosity of water at various temperaturesLawrence Korson, Walter Drost-Hansen, and Frank J. MilleroCite this: J. Phys. Chem. 1969, 73, 1, 34–39Publication Date (Print):January 1, 1969Publication History Published online1 May 2002Published inissue 1 January 1969https://pubs.acs.org/doi/10.1021/j100721a006https://doi.org/10.1021/j100721a006research-articleACS PublicationsRequest reuse permissionsArticle Views12801Altmetric-Citations561LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe apparent molal volumes and adiabatic compressibilities of aqueous amino acids at 25.degree.CFrank J. Millero, Antonio Lo Surdo, and Charles ShinCite this: J. Phys. Chem. 1978, 82, 7, 784–792Publication Date (Print):April 1, 1978Publication History Published online1 May 2002Published inissue 1 April 1978https://pubs.acs.org/doi/10.1021/j100496a007https://doi.org/10.1021/j100496a007research-articleACS PublicationsRequest reuse permissionsArticle Views904Altmetric-Citations551LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

The Coupled Boundary Layer Air–Sea Transfer (CBLAST) field program, conducted from 2002 to 2004, has provided a wealth of new air–sea interaction observations in hurricanes. The wind speed range for which turbulent momentum and moisture exchange coefficients have been derived based upon direct flux measurements has been extended by 30% and 60%, respectively, from airborne observations in Hurricanes Fabian and Isabel in 2003. The drag coefficient (CD) values derived from CBLAST momentum flux measurements show CD becoming invariant with wind speed near a 23 m s−1 threshold rather than a hurricane-force threshold near 33 m s−1 . Values above 23 m s−1 are lower than previous open-ocean measurements. The Dalton number estimates (CE) derived from CBLAST moisture flux measurements are shown to be invariant with wind speeds up to 30 m s −1 which is in approximate agreement with previous measurements at lower winds. These observations imply a CE/CD ratio of approximately 0.7, suggesting that additional energy sources are necessary for hurricanes to achieve their maximum potential intensity. One such additional mechanism for augmented moisture flux in the boundary layer might be “roll vortex” or linear coherent features, observed by CBLAST 2002 measurements to have wavelengths of 0.9–1.2 km. Linear features of the same wavelength range were observed in nearly concurrent RADARSAT Synthetic Aperture Radar (SAR) imagery. As a complement to the aircraft measurement program, arrays of drifting buoys and subsurface floats were successfully deployed ahead of Hurricanes Fabian (2003) and Frances (2004) [16 (6) and 38 (14) drifters (floats), respectively, in the two storms]. An unprecedented set of observations was obtained, providing a four-dimensional view of the ocean response to a hurricane for the first time ever. Two types of surface drifters and three types of floats provided observations of surface and subsurface oceanic currents, temperature, salinity, gas exchange, bubble concentrations, and surface wave spectra to a depth of 200 m on a continuous basis before, during, and after storm passage, as well as surface atmospheric observations of wind speed (via acoustic hydrophone) and direction, rain rate, and pressure. Float observations in Frances (2004) indicated a deepening of the mixed layer from 40 to 120 m in approximately 8 h, with a corresponding decrease in SST in the right-rear quadrant of 3.2°C in 11 h, roughly one-third of an inertial period. Strong inertial currents with a peak amplitude of 1.5 m s−1 were observed. Vertical structure showed that the critical Richardson number was reached sporadically during the mixed-layer deepening event, suggesting shear-induced mixing as a prominent mechanism during storm passage. Peak significant waves of 11 m were observed from the floats to complement the aircraft-measured directional wave spectra.

The National Oceanic and Atmospheric Administration (NOAA)/NASA Oceans Pathfinder sea surface temperature (SST) data are derived from measurements made by the advanced very high resolution radiometers (AVHRRs) on board the NOAA 7, 9, 11, and 14 polar orbiting satellites. All versions of the Pathfinder SST algorithm are based on the NOAA/National Environmental Satellite Data and Information Service nonlinear SST operational algorithm (NLSST). Improvements to the NLSST operational algorithm developed by the Pathfinder program include the use of monthly calibration coefficients selected on the basis of channel brightness temperature difference ( T 4 – T 5 ). This channel difference is used as a proxy for water vapor regime. The latest version (version 4.2) of the Pathfinder processing includes the use of decision trees to determine objectively pixel cloud contamination and quality level (0–7) of the SST retrieval. The 1985–1998 series of AVHRR global measurements has been reprocessed using the Pathfinder version 4.2 processing protocol and is available at various temporal and spatial resolutions from NASA's Jet Propulsion Laboratory Distributed Active Archive Center. One of the highlights of the Pathfinder program is that in addition to the daily global area coverage fields, a matchup database of coincident in situ buoy and satellite SST observations also is made available for independent algorithm development and validation.

The speed of sound in standard seawater (diluted with pure water and evaporated) have been measured relative to pure water with a Nusonics single-transducer sound velocimeter as a function of salinity (5–40°/00), temperature 0°–40°C, and applied pressure (0–1000 bars). The effect of pressure on the relative speeds of sound, (UP−UPH2O) -UO−UOH2O), have been fitted to an equation of the form (with a standard deviation of 0.19 msec−1) (UP−UPH2O) - (UO−UOH2O) =AS (°/oo)+BS (°/oo)3/2 +CS (°/oo)2, where U and UH20 are the speeds of sound in seawater and pure water, respectively; superscripts P and O are used to denote applied pressure P and O (1 atm); A, B, and C are temperature- and pressure-dependent parameters; S (o/oo) is the salinity in parts per thousand. This equation has been combined with the refitted high-pressure pure-water sound-speed equation of Wilson [Naval Ordnance Lab. Rep.(1959)], Chen and Millero [J. Acoust. Soc. Am. 60, 1270–1273 (1976)], and the 1-atm seawater sound-speed data of Millero and Kubinski [J. Acoust. Soc. Am. 57, 312–319 (1975)] to calculate the speeds of sound for seawater at various salinities, temperatures, and pressures. Our results agree with the work of Wilson on the average to 0.36 msec−1 over the range of 5 to 40o/oo salinity, 0° to 30°C, and 0 to 1000 bars. Over the oceanic range our results agree on the average with the work of Wilson to 0.3 msec−1 (maximum deviation 0.6 msec−1), and with the work of Del Grosso to 0.5 msec−1 (maximum deviation 0.9 msec−1). The better agreement of our results with those of Wilson may be fortuitous since our measurements were made relative to his pure-water data.

The isothermal compressibility of water from 0 to 100 °C and 0 to 1000 bar has been determined from Wilson's sound velocity measurements which have been normalized to Kell's 1 atm values. The isothermal compressibilities determined from the sound velocities have been fit, with a maximum deviation in compressibility of ± 0.016 × 10−6 bar−1, to an extended bulk modulus equation V 0P/(V0-VP) = B + A1P + A2P2, where V0 and VP are the specific volume at an applied pressure of zero and P; and B, A1, and A2 are temperature dependent constants. Our specific volume results are in reasonable agreement with the work of Kell and Whalley at low pressures; however, our results at high pressures (1000 bar) disagree by as much as 169 ppm (the average deviation is approximately 115 ppm). A comparison of the compressibilities indicates a parabolic shift in Kell and Whalley's work with a maximum of approximately 0.205 × 10−6 bar−1 at 400 bar and 5 °C. Since the velocity of sound data is extremely reliable (± 0.2 m/sec) and the maximum error in the compressibilities derived from the sound data is within ± 0.016 × 10−6 bar−1, our PVT results based upon the sound data are more accurate than any direct measurements made to date.

The carbon isotopic fractionation accompanying formation of biomass by alkenone‐producing algae in natural marine environments varies systematically with the concentration of dissolved phosphate. Specifically, if the fractionation is expressed by є P ≈ δ e − δ p , where δ e and δ p are the δ 13 C values for dissolved CO 2 and for algal biomass (determined by isotopic analysis of C 37 alkadienones), respectively, and if C e is the concentration of dissolved CO 2 , μmol kg −1 , then b = 38 + 160*[PO 4 ], where [PO 4 ] is the concentration of dissolved phosphate, μM, and b = (25 − є p ) C e . The correlation found between b and [PO 4 ] is due to effects linking nutrient levels to growth rates and cellular carbon budgets for alkenone‐containing algae, most likely by trace‐metal limitations on algal growth. The relationship reported here is characteristic of 39 samples (r 2 = 0.95) from the Santa Monica Basin (six different times during the annual cycle), the equatorial Pacific (boreal spring and fall cruises as well as during an iron‐enrichment experiment), and the Peru upwelling zone. Points representative of samples from the Sargasso Sea ([PO 4 ] ≤ 0.1 μM) fall above the b = f [PO 4 ] line. Analysis of correlations expected between μ (growth rate), є p , and C e shows that, for our entire data set, most variations in є p result from variations in μ rather than C e . Accordingly, before concentrations of dissolved CO 2 can be estimated from isotopic fractionations, some means of accounting for variations in growth rate must be found, perhaps by drawing on relationships between [PO 4 ] and Cd/Ca ratios in shells of planktonic foraminifera.

We present intriguing evidence that the majority of El Niño events over the past four decades are preceded by a distinctive sea‐surface warming and southwesterly wind anomaly in the vicinity of the Intertropical Convergence Zone (ITCZ) during the boreal spring. This phenomenon, known as the Meridional Mode (MM), is shown to be intrinsic to the thermodynamic coupling between the atmosphere and ocean. The MM effectively acts as a conduit through which the extratropical atmosphere influences ENSO. Modeling results further suggest that the MM plays a vital role in the seasonal phase‐locking behavior of ENSO. The findings provide a new perspective for understanding the important role of thermodynamic ocean‐atmosphere feedback in ENSO and may have profound implications for ENSO prediction, particularly the unresolved issue of the spring predictability barrier.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRates and Mechanism of Fe(II) Oxidation at Nanomolar Total Iron ConcentrationsD. Whitney. King, Heather A. Lounsbury, and Frank J. MilleroCite this: Environ. Sci. Technol. 1995, 29, 3, 818–824Publication Date (Print):March 1, 1995Publication History Published online1 May 2002Published inissue 1 March 1995https://pubs.acs.org/doi/10.1021/es00003a033https://doi.org/10.1021/es00003a033research-articleACS PublicationsRequest reuse permissionsArticle Views1923Altmetric-Citations301LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

he record-setting 2005 hurricane season has highlighted the urgent need for a better understanding of the factors that contribute to hurricane intensity, and for the development of corresponding advanced hurricane prediction models to improve intensity forecasts. The lack of skill in present forecasts of hurricane intensity may be attributed, in part, to deficiencies in the current prediction models-insufficient grid resolution, inadequate surface and boundary-layer formulations, and the lack of full coupling to a dynamic ocean. The extreme high winds, intense rainfall, large ocean waves, and copious sea spray in hurricanes push the surface-exchange parameters for temperature, water vapor, and momentum into untested regimes.

Coral reef fish have considerable larval behavioral capabilities that can lead to successful completion of the early pelagic life phase. In particular, vertical migration during ontogeny increases retention near natal reefs and decreases losses due to transport by currents. For those larvae that are not returning home, the relative influence of behavior (biology) and currents (physics) on their arrival pattern among adjacent and distant reefs is not known. Moreover, interactions of the naturally small-scale larval movements with those of larger-scale currents need to be evaluated with regard to the spatial patterns of recruitment. We used an offline Lagrangian stochastic modeling approach to explore the relative influence of physical (i.e. eddy perturbation, diffusion) and biological processes (i.e. vertical movement, mortality) on the connectivity of the coral reef fish population in the western Caribbean, a region with complex geomorphology and circulation. This study revealed that the impact of larval behavior extends beyond enhancing the process of self-recruitment by changing population connectivity patterns. Connectivity was significantly influenced by larval vertical movement, survival, and by the eddy field, all controlling arrival patterns near reefs. A sensitivity analysis was done to gauge the robustness of the results by varying the model parameters. We found that particle-tracking models with homogeneous parameterization of the sub-grid motion tended to bias dispersal from and along the reef track, which can be mitigated by using spatially explicit parameters calculated from the Eulerian velocity fields. Finally, larval survival emerged as a key component for connectivity estimates, the study of which poses a great challenge in tropical ecosystems.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxidation of H2S in seawater as a function of temperature, pH, and ionic strengthFrank J. Millero, Scott. Hubinger, Marino. Fernandez, and Stephen. GarnettCite this: Environ. Sci. Technol. 1987, 21, 5, 439–443Publication Date (Print):May 1, 1987Publication History Published online1 May 2002Published inissue 1 May 1987https://pubs.acs.org/doi/10.1021/es00159a003https://doi.org/10.1021/es00159a003research-articleACS PublicationsRequest reuse permissionsArticle Views1450Altmetric-Citations196LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Bacterial abundance, DOC concentrations, and bacterioplankton community structure (using PCR-based techniques) were measured in 5 seawater culture experiments conducted near the Bermuda Atlantic Time-series Study (BATS) site in the northwestern Sargasso Sea.Cultures were amended with inorganic and organic nutrients, alone or in combination, to test the existence of the 'malfunctioning microbial loop' during late spring and summer at BATS.Objectives of the study were to determine whether (1) alleviating grazing pressure and inorganic nutrient limitation stimulated DOC remineralization by bacterioplankton; (2) a combination of organic and inorganic nutrients affect bacterial production and utilization of seasonally accumulated DOC; and (3) shifts in bacterioplankton community structure are associated with nutrient amendment and DOC utilization.In unamended cultures natural assemblages of surface bacterioplankton did not utilize detectable amounts of naturally occurring 'semi-labile' DOC over time-scales of days to weeks.Neither bacterial production nor utilization of DOC was enhanced with the addition of inorganic N or P (alone or in combination).Labile DOC amendments stimulated bacterial production and DOC utilization, even in the absence of measurable inorganic nutrients, indicating that the bacterioplankton assemblage was initially energy limited, but did not stimulate utilization of seasonally accumulated DOC.The combination of inorganic N and P with labile DOC enhanced both bacterial production and utilization of 'semi-labile' DOC.Changes in bacterioplankton community rDNA gene profiles were minor in the control and inorganic treatments; however, utilization of 'semi-labile' DOC in the organic plus inorganic nutrient treatments coincided with significant changes in bacterioplankton community structure.These data suggest that bacterioplankton community structure, as well as nutrient regime, may be important factors governing the utilization of recalcitrant DOC substrates in the northwestern Sargasso Sea.

This study presents basin‐wide anthropogenic CO 2 inventory estimates for the Indian Ocean based on measurements from the World Ocean Circulation Experiment/Joint Global Ocean Flux Study global survey. These estimates employed slightly modified ΔC* and time series techniques originally proposed by Gruber et al. [1996] and Wallace [1995], respectively. Together, the two methods yield the total oceanic anthropogenic CO 2 and the carbon increase over the past 2 decades. The highest concentrations and the deepest penetrations of anthropogenic carbon are associated with the Subtropical Convergence at around 30° to 40°S. With both techniques, the lowest anthropogenic CO 2 column inventories are observed south of 50°S. The total anthropogenic CO 2 inventory north of 35°S was 13.6±2 Pg C in 1995. The inventory increase since GEOSECS (Geochemical Ocean Sections Program) was 4.1±1 Pg C for the same area. Approximately 6.7±1 Pg C are stored in the Indian sector of the Southern Ocean, giving a total Indian Ocean inventory of 20.3 ±3 Pg C for 1995. These estimates are compared to anthropogenic CO 2 inventories estimated by the Princeton ocean biogeochemistry model. The model predicts an Indian Ocean sink north of 35°S that is only 0.61–0.68 times the results presented here; while the Southern Ocean sink is nearly 2.6 times higher than the measurement‐based estimate. These results clearly identify areas in the models that need further examination and provide a good baseline for future studies of the anthropogenic inventory.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe apparent and partial molal volume of aqueous sodium chloride solutions at various temperaturesFrank J. MilleroCite this: J. Phys. Chem. 1970, 74, 2, 356–362Publication Date (Print):January 1, 1970Publication History Published online1 May 2002Published inissue 1 January 1970https://pubs.acs.org/doi/10.1021/j100697a022https://doi.org/10.1021/j100697a022research-articleACS PublicationsRequest reuse permissionsArticle Views3476Altmetric-Citations175LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

High‐frequency (HF) radar systems can provide periodic, two‐dimensional, vector current estimates over an area approaching 1000 km 2 . As the use of these HF systems has gained wider acceptance, a number of attempts have been made to estimate the accuracy of such systems. However, comparisons of HF radar current estimates with in situ sensors are difficult to interpret since HF systems measure currents averaged over an area of ∼1 km 2 and to a depth of only ∼50 cm while in situ sensors measure currents at a point and somewhat greater depths (∼1 to 10 m). Previous studies of the accuracy of HF radar technology have thus attributed the differences observed between HF radar and in situ sensors to an unknown combination of vertical shear, horizontal inhomogeneity, in situ instrument errors, and HF radar system errors. This study examines the accuracy of HF radar current measurements using data from the 1993 High Resolution Remote Sensing Experiment, conducted off Cape Hatteras, North Carolina. Data from four shipborne in situ current meters are compared with data from an Ocean Surface Current Radar (OSCR), a commercial current‐measuring radar. We attempt to discern the predominant sources of error in these data by using multiple simultaneous measurements from different sensors and by examining the variation of observed current differences as a function of location. The results suggest an upper bound on the accuracy of the OSCR‐derived radial currents of 7 to 8 cm/s.

In 2005, NOAA's Hurricane Research Division (HRD), part of the Atlantic Oceanographic and Meteorological Laboratory, began a multiyear experiment called the Intensity Forecasting Experiment (IFEX). By emphasizing a partnership among NOAA's HRD, Environmental Modeling Center (EMC), National Hurricane Center (NHC), Aircraft Operations Center (AOC), and National Environmental Satellite Data Information Service (NESDIS), IFEX represents a new approach for conducting hurricane field program operations. IFEX is intended to improve the prediction of tropical cyclone (TC) intensity change by 1) collecting observations that span the TC life cycle in a variety of environments; 2) developing and refining measurement technologies that provide improved real-time monitoring of TC intensity, structure, and environment; and 3) improving the understanding of the physical processes important in intensity change for a TC at all stages of its life cycle. This paper presents a summary of the accomplishments of IFEX during the 2005 hurricane season. New and refined technologies for measuring such fields as surface and three-dimensional wind fields, and the use of unmanned aerial vehicles, were achieved in a variety of field experiments that spanned the life cycle of several tropical cyclones, from formation and early organization to peak intensity and subsequent landfall or extratropical transition. Partnerships with other experiments during 2005 also expanded the spatial and temporal coverage of the data collected in 2005. A brief discussion of the plans for IFEX in 2006 is also provided.

During the summer Marginal Ice Zone Experiment in Fram Strait in 1983 and 1984, fourteen mesoscale eddies, in both deep and shallow water, were studied between 78° and 81°N. Sampling combined satellite and aircraft remote sensing observations, conductivity‐temperature‐depth observations, drift of surface and subsurface floats and current meter measurements. Typical scales of these eddies were 20–40 km. Rotation was mainly cyclonic with a maximum speed, in several cases subsurface of up to 40 cm s −1 . Observations further suggest that the eddy lifetime was at least 20 to 30 days. Five generation sources are suggested for these eddies. Several of the eddies were topographically trapped, while others, primarily formed by combined baroclinic and barotropic instability, moved as much as 10–15 km d −1 with the mean current. The vorticity balance in the nontrapped eddies is dominated by the stretching of isopycnals accompanied by a change in the radial shear. In the most completely observed eddy south of 79°N the available potential energy exceeded the kinetic energy by a factor of 2. Quantitative estimates suggest that the abundance of these eddies enhances the ice edge melt up to 1–2 km d −1 .