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Jamie Morison

Senior Principal Oceanographer

Affiliate Professor, Oceanography






Dr. Morison's main focus centers on the study of Arctic Ocean change. He has been the principal investigator for the NSF-supported North Pole Environmental Observatory since 2000. He is involved with using remote sensing, principally NASA's Gravity Recovery and Climate Experiment (GRACE), to track changes in Arctic Ocean circulation and freshwater distribution. He is also continuing a long-term interest in small-scale processes by studying interplay among Arctic change, internal waves and mixing.

Department Affiliation

Polar Science Center


B.S. Mechanical Engineering, University of California at Davis, 1969

M.S. Mechanical Engineering, University of California at Davis, 1971

Ph.D. Geophysics, University of Washington, 1980


Stratified Ocean Dynamics of the Arctic — SODA

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31 Oct 2016

Vertical and lateral water properties and density structure with the Arctic Ocean are intimately related to the ocean circulation, and have profound consequences for sea ice growth and retreat as well as for prpagation of acoustic energy at all scales. Our current understanding of the dynamics governing arctic upper ocean stratification and circulation derives largely from a period when extensive ice cover modulated the oceanic response to atmospheric forcing. Recently, however, there has been significant arctic warming, accompanied by changes in the extent, thickness distribution, and properties of the arctic sea ice cover. The need to understand these changes and their impact on arctic stratification and circulation, sea ice evolution, and the acoustic environment motivate this initiative.

North Pole Environmental Observatory

The observatory is staffed by an international research team that establishes a camp at the North Pole each spring to take the pulse of the Arctic Ocean and learn how the world's northernmost sea helps regulate global climate.


Study of Environmental Arctic Change

SEARCH is an interagency effort to understand the nature, extent, and future development of the system-scale change presently seen in the Arctic. These changes are occuring across terrestrial, oceanic, atmospheric, and human systems.



Arctic Sea Ice Extent and Volume Dip to New Lows

By mid-September, the sea ice extent in the Arctic reached the lowest level recorded since 1979 when satellite mapping began.

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15 Oct 2012

APL-UW polar oceanographers and climatologists are probing the complex ice–ocean–atmosphere system through in situ and remote sensing observations and numerical model simulations to learn how and why.

Changing Freshwater Pathways in the Arctic Ocean

Freshening in the Canada Basin of the Arctic Ocean began in the 1990s. Polar scientist Jamie Morison and colleagues report new insights on the freshening based in part on Arctic-wide views from two satellite system.

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5 Jan 2012

The Arctic Ocean is a repository for a tremendous amount of river runoff, especially from several huge Russian rivers. During the spring of 2008, APL-UW oceanographers on a hydrographic survey in the Arctic detected major shifts in the amount and distribution of fresh water. The Canada basin had freshened, but had the entire Arctic Ocean?

Analysis of satellite records shows that salinity increased on the Russian side of the Arctic and decreased in the Beaufort Sea on the Canadian side. With an Arctic-wide view of circulation from satellite sensors, researchers were able to determine that atmospheric forcing had shifted the transpolar drift counterclockwise and driven Russian runoff east to the Canada Basin.

Oceanography from Space

In the North Atlantic and Arctic oceans observations by sensors on orbiting satellites are giving oceanographers insight to ocean processes on vast spatial and temporal scales.

1 Dec 2011


2000-present and while at APL-UW

An edge-referenced surface fresh layer in the Beaufort Sea seasonal ice zone

Dewey, S.R., J.H. Morison, and J. Zhang, "An edge-referenced surface fresh layer in the Beaufort Sea seasonal ice zone," J. Phys. Oceanogr., 47, 1125-1144, doi:10.1175/JPO-D-16-0158.1, 2017.

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1 May 2017

To understand the factors causing the interannual variations in the summer retreat of the Beaufort Sea ice edge, Seasonal Ice Zone Reconnaissance Surveys (SIZRS) aboard U.S. Coast Guard Arctic Domain Awareness flights were made monthly from June to October in 2012, 2013, and 2014. The seasonal ice zone (SIZ) is where sea ice melts and reforms annually and encompasses the nominally narrower marginal ice zone (MIZ) where a mix of open-ocean and ice pack processes prevail. Thus, SIZRS provides a regional context for the smaller-scale MIZ processes. Observations with aircraft expendable conductivity–temperature–depth probes reveal a salinity pattern associated with large-scale gyre circulation and the seasonal formation of a shallow (~20 m) fresh layer moving with the ice edge position. Repeat occupations of the SIZRS lines from 72° to 76°N on 140° and 150°W allow a comparison of observed hydrography to atmospheric indices. Using this relationship, the basinwide salinity signals are separated from the fresh layer associated with the ice edge. While this layer extends northward under the ice edge as the melt season progresses, low salinities and warm temperatures appear south of the edge. Within this fresh layer, average salinity is correlated with distance from the ice edge. The salinity observations suggest that the upper-ocean freshening over the summer is dominated by local sea ice melt and vertical mixing. A Price–Weller–Pinkel model analysis reveals that observed changes in heat content and density structure are also consistent with a 1D mixing process.

Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean

Polyakov, I.V., and 15 others including M.B. Alkire, J. Guthrie, and J. Morison, "Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean," Science, doi: 10.1126/science.aai8204, 2017.

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6 Apr 2017

Arctic sea-ice loss is a leading indicator of climate change and can be attributed, in large part, to atmospheric forcing. Here, we show that recent ice reductions, weakening of the halocline, and shoaling of intermediate-depth Atlantic Water layer in the eastern Eurasian Basin have increased winter ventilation in the ocean interior, making this region structurally similar to that of the western Eurasian Basin. The associated enhanced release of oceanic heat has reduced winter sea-ice formation at a rate now comparable to losses from atmospheric thermodynamic forcing, thus explaining the recent reduction in sea-ice cover in the eastern Eurasian Basin. This encroaching “atlantification” of the Eurasian Basin represents an essential step toward a new Arctic climate state, with a substantially greater role for Atlantic inflows.

Proxy representation of Arctic Ocean bottom pressure variability: Bridging gaps in GRACE observations

Peralta-Ferriz, C., J.H. Morison, and J.M. Wallace, "Proxy representation of Arctic Ocean bottom pressure variability: Bridging gaps in GRACE observations," Geophys. Res. Lett., 43, 9183-9191, doi:10.1002/2016GL070137, 2016.

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16 Sep 2016

Using time-varying ocean bottom pressure (OBP) from the Gravity Recovery and Climate Experiment (GRACE), a 9 year in situ OBP record at the North Pole, and wind reanalysis products, we perform a linear regression analysis to identify primary predictor time series that enable us to create a proxy representation of the Arctic time-varying OBP that explains the largest fraction of the observed Arctic OBP variability. After cross validation, two predictorsםNorth Pole OBP record and wind-OBP coupling from maximum covariance analysis—explain 50% of the total variance of the Arctic OBP. This work provides a means for bridging existing short gaps in GRACE measurements and potentially longer future gaps that may result if GRACE and its follow-on mission do not overlap. The technique may be applicable to bridge gaps in GRACE measurements in other oceanic regions.

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Stratified Ocean Dynamics in the Arctic: Science and Experiment Plan

Lee, C.M., et al., "Stratified Ocean Dynamics in the Arctic: Science and Experiment Plan," APL-UW TR 1601, Technical Report, Applied Physics Laboratory, University of Washington, Seattle, September 2016, 46pp.

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15 Sep 2016

Vertical and lateral water properties and density structure within the Arctic Ocean are intimately related to the ocean circulation, and have profound consequences for sea ice growth and retreat as well as for propagation of acoustic energy at all scales. Our current understanding of the dynamics governing arctic upper ocean stratification and circulation derives largely from a period when extensive ice cover modulated the oceanic response to atmospheric forcing. Recently, however, there has been significant arctic warming, accompanied by changes in the extent, thickness distribution, and properties of the arctic sea ice cover. The need to understand these changes and their impact on arctic stratification and circulation, sea ice evolution, and the acoustic environment motivate the Office of Naval Research (ONR) Stratified Ocean Dynamics of the Arctic Departmental Research Initiative.

Sea ice melt onset associated with lead opening during the spring/summer transition near the North Pole

Vivier, F., J.K. Hutchings, Y. Kawaguchi, T. Kikuchi, J.H. Morison, A. Lourenco, and T. Noguchi, "Sea ice melt onset associated with lead opening during the spring/summer transition near the North Pole," J. Geophys. Res., 121, 2499-2522, doi:10.1002/2015JC011588, 2016.

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13 Apr 2016

In the central Arctic Ocean, autonomous observations of the ocean mixed layer and ice documented the transition from cold spring to early summer in 2011. Ice-motion measurements using GPS drifters captured three events of lead opening and ice ridge formation in May and June. Satellite sea ice concentration observations suggest that locally observed lead openings were part of a larger-scale pattern. We clarify how these ice deformation events are linked with the onset of basal sea ice melt, which preceded surface melt by 20 days. Observed basal melt and ocean warming are consistent with the available input of solar radiation into leads, once the advent of mild atmospheric conditions prevents lead refreezing. We use a one-dimensional numerical simulation incorporating a Local Turbulence Closure scheme to investigate the mechanisms controlling basal melt and upper ocean warming. According to the simulation, a combination of rapid ice motion and increased solar energy input at leads promotes basal ice melt, through enhanced mixing in the upper mixed layer, while slow ice motion during a large lead opening in mid-June produced a thin, low-density surface layer. This enhanced stratification near the surface facilitates storage of solar radiation within the thin layer, instead of exchange with deeper layers, leading to further basal ice melt preceding the upper surface melt.

Sea surface height and dynamic topography of the ice-covered oceans from CryoSat-2, 2011–2014

Kwok, R., and J. Morison, "Sea surface height and dynamic topography of the ice-covered oceans from CryoSat-2, 2011–2014," J. Geophys. Res., 121, 674-692, doi:10.1002/2015JC011357, 2016.

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1 Jan 2016

We examine 4 years (2011–2014) of sea surface heights (SSH) from CryoSat-2 (CS-2) over the ice-covered Arctic and Southern Oceans. Results are from a procedure that identifies and determines the heights of sea surface returns. Along 25 km segments of satellite ground tracks, variability in the retrieved SSHs is between –2 and 3 cm (standard deviation) in the Arctic and is slightly higher (–3 cm) in the summer and the Southern Ocean. Average sea surface tilts (along these 25 km segments) are 0.01%u2009±%u20093.8 cm/10 km in the Arctic, and slightly lower (0.01%u2009±%u20092.0 cm/10 km) in the Southern Ocean. Intra-seasonal variability of CS-2 dynamic ocean topography (DOT) in the ice-covered Arctic is nearly twice as high as that of the Southern Ocean. In the Arctic, we find a correlation of 0.92 between 3 years of DOT and dynamic heights (DH) from hydrographic stations. Further, correlation of 4 years of area-averaged CS-2 DOT near the North Pole with time-variable ocean-bottom pressure from a pressure gauge and from GRACE, yields coefficients of 0.83 and 0.77, with corresponding differences of <3 cm (RMS). These comparisons contrast the length scale of baroclinic and barotropic features and reveal the smaller amplitude barotropic signals in the Arctic Ocean. Broadly, the mean DOT from CS-2 for both poles compares well with those from the ICESat campaigns and the DOT2008A and DTU13MDT fields. Short length scale topographic variations, due to oceanographic signals and geoid residuals, are especially prominent in the Arctic Basin but less so in the Southern Ocean.

Observational validation of the diffusive convective flux laws in the Amundsen Basin, Arctic Ocean

Guthrie, J.D., I. Fer, and J. Morison, "Observational validation of the diffusive convective flux laws in the Amundsen Basin, Arctic Ocean," J. Geophys. Res., 120, 7880-7896, doi:10.1002/2015JC010884, 2015.

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1 Dec 2015

The low levels of mechanically driven mixing in many regions of the Arctic Ocean make double diffusive convection virtually the only mechanism for moving heat up from the core of Atlantic Water towards the surface. In an attempt to quantify double diffusive heat fluxes in the Arctic Ocean, a temperature microstructure experiment was performed as a part of the North Pole Environmental Observatory (NPEO) 2013 field season from the drifting ice station Barneo located in the Amundsen Basin near the Lomonosov Ridge (89.5°N, 75°W). A diffusive convective thermohaline staircase was present between 150 and 250 m in nearly all of the profiles. Typical vertical heat fluxes across the high-gradient interfaces were consistently small, O(10-1) W m-2. Our experiment was designed to resolve the staircase and differed from earlier Arctic studies that utilized inadequate instrumentation or sampling. Our measured fluxes from temperature microstructure agree well with the laboratory derived flux laws compared to previous studies, which could find agreement only to within a factor of two to four. Correlations between measured and parameterized heat fluxes are slightly higher when using the more recent Flanagan et al. [2013] laboratory derivation than the more commonly used derivation presented in Kelley [1990]. Nusselt versus Rayleigh number scaling reveals the convective exponent to be closer to 0.29 as predicted by recent numerical simulations of single-component convection rather than the canonical 1/3 assumed for double diffusion. However, the exponent appears to be sensitive to how convective layer height is defined.

Variability in the meteoric water, sea-ice melt, and Pacific water contributions to the central Arctic Ocean, 2000–2014

Alkire, M.B., J. Morison, and R. Andersen, "Variability in the meteoric water, sea-ice melt, and Pacific water contributions to the central Arctic Ocean, 2000–2014," J. Geophys. Res., 120, 1573-1598, doi:10.1002/2014JC010023, 2015.

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12 Mar 2015

Fourteen years (2000–2014) of bottle chemistry data collected during the North Pole Environmental Observatory were compiled to examine variations in the composition of freshwater (meteoric water, net sea-ice meltwater, and Pacific water) over mixed layer of the Central Arctic Ocean. In addition to significant spatial and interannual variability, there was a general decrease in meteoric water (MW) fractions at the majority of stations reoccupied over the duration of the program that was approximately balanced by a concomitant increase in freshwater from sea-ice melt (SIM FW) between 2000 and 2012. Inventories (0–120 m) of MW and SIM FW computed using available data between 2005 and 2012 exhibited similar variations over the study area, allowing for first-order estimates of the mean annual changes in MW (–389±194 km3 yr-1) and SIM FW (292±97 km3 yr-1) for the Central Arctic region. These mean annual changes were attributed to the diversion of Siberian river runoff to the Beaufort Gyre and the overall reduction of sea ice volume across the Arctic, respectively. In addition to this lower-frequency variability, spatial gradients and interannual variations in MW, SIM FW, and Pacific water contributions to specific locations were attributed to shifts in the Transpolar Drift that advects waters of eastern and western Arctic origin through the study area.

Accuracy assessment of global barotropic ocean tide models

Stammer, D., et al., including J. Morison, "Accuracy assessment of global barotropic ocean tide models," Rev. Geophys., 52, 243-282, doi:10.1002/2014RG000450, 2014.

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7 Aug 2014

The accuracy of state-of-the-art global barotropic tide models is assessed using bottom pressure data, coastal tide gauges, satellite altimetry, various geodetic data on Antarctic ice shelves, and independent tracked satellite orbit perturbations. Tide models under review include empirical, purely hydrodynamic ("forward"), and assimilative dynamical, i.e., constrained by observations. Ten dominant tidal constituents in the diurnal, semidiurnal, and quarter-diurnal bands are considered. Since the last major model comparison project in 1997, models have improved markedly, especially in shallow-water regions and also in the deep ocean. The root-sum-square differences between tide observations and the best models for eight major constituents are approximately 0.9, 5.0, and 6.5 cm for pelagic, shelf, and coastal conditions, respectively. Large intermodel discrepancies occur in high latitudes, but testing in those regions is impeded by the paucity of high-quality in situ tide records. Long-wavelength components of models tested by analyzing satellite laser ranging measurements suggest that several models are comparably accurate for use in precise orbit determination, but analyses of GRACE intersatellite ranging data show that all models are still imperfect on basin and subbasin scales, especially near Antarctica. For the M2 constituent, errors in purely hydrodynamic models are now almost comparable to the 1980-era Schwiderski empirical solution, indicating marked advancement in dynamical modeling. Assessing model accuracy using tidal currents remains problematic owing to uncertainties in in situ current meter estimates and the inability to isolate the barotropic mode. Velocity tests against both acoustic tomography and current meters do confirm that assimilative models perform better than purely hydrodynamic models.

Arctic Ocean circulation patterns revealed by GRACE

Peralta-Ferriz, C., J.H. Morison, J.H. Wallace, J.A. Bonin, and J. Zhang, "Arctic Ocean circulation patterns revealed by GRACE," J. Clim., 27, 1445-1468, doi:10.1175/JCLI-D-13-00013.1, 2014.

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1 Feb 2014

Measurements of ocean bottom pressure (OBP) anomalies from the satellite mission Gravity Recovery and Climate Experiment (GRACE), complemented by information from two ocean models, are used to investigate the variations and distribution of the Arctic Ocean mass from 2002 through 2011. The forcing and dynamics associated with the observed OBP changes are explored. Major findings are the identification of three primary temporal–spatial modes of OBP variability at monthly-to-interannual time scales with the following characteristics. Mode 1 (50% of the variance) is a wintertime basin-coherent Arctic mass change forced by southerly winds through Fram Strait, and to a lesser extent through Bering Strait. These winds generate northward geostrophic current anomalies that increase the mass in the Arctic Ocean. Mode 2 (20%) reveals a mass change along the Siberian shelves, driven by surface Ekman transport and associated with the Arctic Oscillation. Mode 3 (10%) reveals a mass dipole, with mass decreasing in the Chukchi, East Siberian, and Laptev Seas, and mass increasing in the Barents and Kara Seas. During the summer, the mass decrease on the East Siberian shelves is due to the basin-scale anticyclonic atmospheric circulation that removes mass from the shelves via Ekman transport. During the winter, the forcing mechanisms include a large-scale cyclonic atmospheric circulation in the eastern-central Arctic that produces mass divergence into the Canada Basin and the Barents Sea. In addition, strengthening of the Beaufort high tends to remove mass from the East Siberian and Chukchi Seas. Supporting previous modeling results, the month-to-month variability in OBP associated with each mode is predominantly of barotropic character.

Diffusive vertical heat flux in the Canada Basin of the Arctic Ocean inferred from moored instruments

Lique, C., J.D. Guthrie, M. Steele, A. Proshutinsky, J.H. Morison, and R. Krishfield, "Diffusive vertical heat flux in the Canada Basin of the Arctic Ocean inferred from moored instruments," J. Geophys. Res., 119, 496-508, doi:10.1002/2013JC009346, 2014.

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1 Jan 2014

Observational studies have shown that an unprecedented warm anomaly has recently affected the temperature of the Atlantic Water (AW) layer lying at intermediate depth in the Arctic Ocean. Using observations from four profiling moorings, deployed in the interior of the Canada Basin between 2003 and 2011, the upward diffusive vertical heat flux from this layer is quantified. Vertical diffusivity is first estimated from a fine-scale parameterization method based on CTD and velocity profiles. Resulting diffusive vertical heat fluxes from the AW are in the range 0.1–0.2 W m-2 on average. Although large over the period considered, the variations of the AW temperature maximum yields small variations for the temperature gradient and thus the vertical diffusive heat flux. In most areas, variations in upward diffusive vertical heat flux from the AW have only a limited effect on temperature variations of the overlying layer. However, the presence of eddies might be an effective mechanism to enhance vertical heat transfer, although the small number of eddies sampled by the moorings suggest that this mechanism remains limited and intermittent in space and time. Finally, our results suggest that computing diffusive vertical heat flux with a constant vertical diffusivity of ~2 x 10-6 m2 s-1 provides a reasonable estimate of the upward diffusive heat transfer from the AW layer, although this approximation breaks down in the presence of eddies.

Hydrographic changes in the Lincoln Sea in the Arctic Ocean with focus on an upper ocean freshwater anomaly between 2007 and 2010

De Steur, L., M. Steele, E. Hansen, J. Morison, I. Polyakov, S.M. Olsen, H. Melling, F.A. McLaughlin, R. Kwok, W.M. Smethie, and P. Schlosser, "Hydrographic changes in the Lincoln Sea in the Arctic Ocean with focus on an upper ocean freshwater anomaly between 2007 and 2010," J. Geophys. Res., 118, 4699-4715, doi:10.1002/jgrc.20341, 2013.

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1 Sep 2013

Hydrographic data from the Arctic Ocean show that freshwater content in the Lincoln Sea, north of Greenland, increased significantly from 2007 to 2010, slightly lagging changes in the eastern and central Arctic. The anomaly was primarily caused by a decrease in the upper ocean salinity. In 2011 upper ocean salinities in the Lincoln Sea returned to values similar to those prior to 2007. Throughout 2008—2010, the freshest surface waters in the western Lincoln Sea show water mass properties similar to fresh Canada Basin waters north of the Canadian Arctic Archipelago. In the northeastern Lincoln Sea fresh surface waters showed a strong link with those observed in the Makarov Basin near the North Pole. The freshening in the Lincoln Sea was associated with a return of a subsurface Pacific Water temperature signal although this was not as strong as observed in the early 1990s. Comparison of repeat stations from the 2000s with the data from the 1990s at 65°W showed an increase of the Atlantic temperature maximum which was associated with the arrival of warmer Atlantic water from the Eurasian Basin. Satellite-derived dynamic ocean topography of winter 2009 showed a ridge extending parallel to the Canadian Archipelago shelf as far as the Lincoln Sea, causing a strong flow toward Nares Strait and likely Fram Strait. The total volume of anomalous freshwater observed in the Lincoln Sea and exported by 2011 was close to 110 ± 250 km, approximately 13% of the total estimated FW increase in the Arctic in 2008.

Revisiting internal waves and mixing in the Arctic Ocean

Guthrie, J.D., J.H. Morison, and I. Fer, "Revisiting internal waves and mixing in the Arctic Ocean," J. Geophys. Res., 118, 3966-3977, doi:10.1002/jgrc.20294, 2013.

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1 Aug 2013

To determine whether deep background mixing has increased with the diminishment of the Arctic sea ice, we compare recent internal wave energy and mixing observations with historical measurements. Since 2007, the North Pole Environmental Observatory has launched expendable current probes (XCPs) as a part of annual airborne hydrographic surveys in the central Arctic Ocean. Mixing in the upper 500 m is estimated from XCP shear variance and Conductivity-Temperature-Depth (CTD) derived Brunt-Väisälä frequency. Internal wave energy levels vary by an order of magnitude between surveys, although all surveys are less energetic and show more vertical modes than typical midlatitude Garrett–Munk (GM) model spectra. Survey-averaged mixing estimates also vary by an order of magnitude among recent surveys. Comparisons between modern and historical data, reanalyzed in identical fashion, reveal no trend evident over the 30 year period in spite of drastic diminution of the sea ice. Turbulent heat fluxes are consistent with recent double-diffusive estimates. Both mixing and internal wave energy in the Beaufort Sea are lower when compared to both the central and eastern Arctic Ocean, and expanding the analysis to mooring data from the Beaufort Sea reveals little change in that area compared to historical results from Arctic Internal Wave Experiment. We hypothesize that internal wave energy remains lowest in the Beaufort Sea in spite of dramatic declines in sea ice there, because increased stratification amplifies the negative effect of boundary layer dissipation on internal wave energy.

Storm-induced upwelling of high pCO2 waters onto the continental shelf of the western Arctic Ocean and implications for carbonate mineral saturation states

Mathis, J.T., R.S. Pickart, R.H. Byrne, C.L. McNeil, G.W.K. Moore, L.W. Juranek, X. Liu, J. Ma, R.A. Easley, M.M. Elliot, J.N. Cross, S.C. Reisdorph, F. Bahr, J. Morison, T. Lichendorf, and R.A. Feely, "Storm-induced upwelling of high pCO2 waters onto the continental shelf of the western Arctic Ocean and implications for carbonate mineral saturation states," Geophys. Res. Lett., 39, doi:10.1029/2012GL051574, 2012.

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11 Apr 2012

The carbon system of the western Arctic Ocean is undergoing a rapid transition as sea ice extent and thickness decline. These processes are dynamically forcing the region, with unknown consequences for CO2 fluxes and carbonate mineral saturation states, particularly in the coastal regions where sensitive ecosystems are already under threat from multiple stressors. In October 2011, persistent wind-driven upwelling occurred in open water along the continental shelf of the Beaufort Sea in the western Arctic Ocean. During this time, cold (<–1.2°C), salty (>32.4) halocline water — supersaturated with respect to atmospheric CO2 (pCO2 > 550 µatm) and undersaturated in aragonite (< 1.0) was transported onto the Beaufort shelf. A single 10-day event led to the outgassing of 0.18–0.54 Tg-C and caused aragonite undersaturations throughout the water column over the shelf. If we assume a conservative estimate of four such upwelling events each year, then the annual flux to the atmosphere would be 0.72–2.16 Tg-C, which is approximately the total annual sink of CO2 in the Beaufort Sea from primary production. Although a natural process, these upwelling events have likely been exacerbated in recent years by declining sea ice cover and changing atmospheric conditions in the region, and could have significant impacts on regional carbon budgets. As sea ice retreat continues and storms increase in frequency and intensity, further outgassing events and the expansion of waters that are undersaturated in carbonate minerals over the shelf are probable.

Anomalous sea-ice reduction in the Eurasian Basin of the Arctic Ocean during summer 2010

Kawaguchi, Y., J.K. Hutchings, T. Kikuchi, J.H. Morison, and R.A. Krishfield, "Anomalous sea-ice reduction in the Eurasian Basin of the Arctic Ocean during summer 2010," Polar Sci., 6, 39-53, doi:10.1016/j.polar.2011.11.003, 2012.

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1 Apr 2012

During the summer of 2010 ice concentration in the Eurasian Basin, Arctic Ocean was unusually low. This study examines the sea-ice reduction in the Eurasian Basin using ice-based autonomous buoy systems that collect temperature and salinity of seawater under the ice along the course of buoy drift. An array of GPS drifters was deployed with 10 miles radius around an ice-based profiler, enabling the quantitative discussion for mechanical ice divergence/convergence and its contribution to the sea-ice reduction. Oceanic heat fluxes to the ice estimated using buoy motion and mixed-layer (ML) temperature suggest significant spatial difference between fluxes under first-year and multi-year ice. In the former, the ML temperature reached 0.6 K above freezing temperature, providing >60–70 W m-2 of heat flux to the overlying ice, equivalent to about 1.5 m of ice melt over three months. In contrast, the multiyear ice region indicates nearly 40 W m-2 at most and cumulatively produced 0.8 m ice melt. The ice concentration was found to be reduced in association with an extensive low pressure system that persisted over the central Eurasian Basin. SSM/I indicates that ice concentration was reduced by 30–40% while the low pressure persisted. The low ice concentration persisted for 30 days even after the low dissipated. It appears that the wind-forced ice divergence led to enhanced absorption of incident solar energy in the expanded areas of open water and thus to increased ice melt.

Changing Arctic Ocean freshwater pathways

Morison, J., R. Kwok, C. Peralta-Ferriz, M. Alkire, I. Rigor, R. Andersen, and M. Steele, "Changing Arctic Ocean freshwater pathways," Nature, 481, 66-70, doi:10.1038/nature10705, 2012.

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5 Jan 2012

Freshening in the Canada basin of the Arctic Ocean began in the 1990s and continued to at least the end of 2008. By then, the Arctic Ocean might have gained four times as much fresh water as comprised the Great Salinity Anomaly of the 1970s, raising the spectre of slowing global ocean circulation. Freshening has been attributed to increased sea ice melting and contributions from runoff, but a leading explanation has been a strengthening of the Beaufort High — a characteristic peak in sea level atmospheric pressure — which tends to accelerate an anticyclonic (clockwise) wind pattern causing convergence of fresh surface water. Limited observations have made this explanation difficult to verify, and observations of increasing freshwater content under a weakened Beaufort High suggest that other factors must be affecting freshwater content.

Here we use observations to show that during a time of record reductions in ice extent from 2005 to 2008, the dominant freshwater content changes were an increase in the Canada basin balanced by a decrease in the Eurasian basin. Observations are drawn from satellite data (sea surface height and ocean-bottom pressure) and in situ data. The freshwater changes were due to a cyclonic (anticlockwise) shift in the ocean pathway of Eurasian runoff forced by strengthening of the west-to-east Northern Hemisphere atmospheric circulation characterized by an increased Arctic Oscillation index. Our results confirm that runoff is an important influence on the Arctic Ocean and establish that the spatial and temporal manifestations of the runoff pathways are modulated by the Arctic Oscillation, rather than the strength of the wind-driven Beaufort Gyre circulation.

A basin-coherent mode of sub-monthly variability in Arctic Ocean bottom pressure

Peralta-Ferriz, C., J.H. Morison, J.M. Wallace, and J. Zhang, "A basin-coherent mode of sub-monthly variability in Arctic Ocean bottom pressure," Geophys. Res. Lett., 38, doi:10.1029/2011GL048142, 2011.

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22 Jul 2011

A sub-monthly mode of non-tidal variability of ocean bottom pressure (OBP) is observed in a 5-year record of deep-sea bottom pressure at the North Pole. OBP records from other regions in the Arctic show that the North Pole non-tidal mass fluctuation is part of a non-propagating basin-coherent variation that is well represented by the ice-ocean model PIOMAS, with a basin-averaged winter-only RMS of 3.3 cm. Wavelet analysis of the modeled OBP shows that the basin-averaged mass variations are non-stationary and only significant during the winter. The basin-averaged OBP is strongly related to the meridional wind component over the Nordic Seas. The ocean response is consistent with episodic wind forcing driving a northward geostrophic slope current. The mass transport anomaly associated with the mode is significant relative to the annual net mean flow.

Sensor-based profiles of the NO parameter in the central Arctic and southern Canada Basin: New insights regarding the cold halocline

Alkire, M.B., K.K. Falkner, J. Morison, R.W. Collier, C.K. Guay, R.A. Desiderio, I.G. Rigor, and M. McPhee, "Sensor-based profiles of the NO parameter in the central Arctic and southern Canada Basin: New insights regarding the cold halocline," Deep-Sea Res. Part I, 57, 1432-1443, doi:10.1016/j.dsr.2010.07.011, 2010.

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1 Nov 2010

Here we report the first optical, sensor-based profiles of nitrate from the central Makarov and Amundsen and southern Canada basins of the Arctic Ocean. These profiles were obtained as part of the International Polar Year program during spring 2007 and 2008 field seasons of the North Pole Environmental Observatory (NPEO) and Beaufort Gyre Exploration Program (BGEP). These nitrate data were combined with in-situ, sensor-based profiles of dissolved oxygen to derive the first high-resolution vertical NO profiles to be reported for the Arctic Ocean.

The focus of this paper is on the halocline layer that insulates sea ice from Atlantic water heat and is an important source of nutrients for marine ecosystems within and downstream of the Arctic. Previous reports based on bottle data have identified a distinct lower halocline layer associated with an NO minimum at about S=34.2 that was proposed to be formed initially in the Nansen Basin and then advected downstream. Greater resolution afforded by our data reveal an even more pronounced NO minimum within the upper, cold halocline of the Makarov Basin. Thus a distinct lower salinity source ventilated the Makarov and not the Amundsen Basin. In addition, a larger Eurasian River water influence overlies this halocline source in the Makarov. Observations in the southern Canada Basin corroborate previous studies confirming multiple lower halocline influences including diapycnal mixing between Pacific winter waters and Atlantic-derived lower halocline waters, ventilation via brine formation induced in persistent openings in the ice, and cold, O2-rich lower halocline waters originating in the Eurasian Basin. These findings demonstrate that continuous sensing of chemical properties promises to significantly advance understanding of the maintenance and circulation of the halocline.

The Arctic: Ocean [in State of the Climate in 2009]

Proshutinsky, A., et al., including J. Morison, M. Steele, and R. Woodgate, "The Arctic: Ocean [in State of the Climate in 2009]," Bull. Amer. Meteor. Soc., 91, S85-87, 2010.

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1 Jul 2010

This 20th annual State of the Climate report highlights the climate conditions that characterized 2009, including notable extreme events. In total, 37 Essential Climate Variables are reported to more completely characterize the State of the Climate in 2009.

Understanding the annual cycle of the Arctic Ocean bottom pressure

Peralta-Ferriz, C., and J. Morison, "Understanding the annual cycle of the Arctic Ocean bottom pressure," Geophys. Res. Lett, 37, doi:10.1029/2010GL042827, 2010.

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22 May 2010

Ocean bottom pressure (OBP) observations in the Arctic from in situ pressure recorders and the Gravity Recovery and Climate Experiment (GRACE) satellite mission, averaged over the basin, reveal annual oscillations of about 2 cm. The maximum occurs in late summer to early fall and the minimum in late winter to early spring. We derive a simple model of OBP response to runoff and precipitation minus evaporation (P-E) that agrees in phase with the observations and is 10% larger.

Combining satellite altimetry, time-variable gravity, and bottom pressure observations to understand the Arctic Ocean: A transformative opportunity

Kwok, R., et al., including J. Morison, C. Peralta-Ferriz, and M. Steele, "Combining satellite altimetry, time-variable gravity, and bottom pressure observations to understand the Arctic Ocean: A transformative opportunity," In Proceedings, OceanObs'09: Sustained Ocean Observations and Information for Society (Vol. 2), Venice, Italy, 21-25 September 2009, J. Hall, et al., eds. (ESA Publication WPP-306, doi:10.5270/OceanObs09.cwp.58, 2010).

15 Feb 2010

Wintertime mixed layer measurements at Maud Rise, Weddell Sea

Sirevaag, A., M.G. McPhee, J.H. Morison, W.J. Shaw, and T.P. Stanton, "Wintertime mixed layer measurements at Maud Rise, Weddell Sea," J. Geophys. Res., 115, doi:10.1029/2008JC005141, 2010.

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12 Feb 2010

Sea ice plays a crucial role in the exchange of heat between the ocean and the atmosphere, and areas of intense air-sea-ice interaction are important sites for water mass modification. The Weddell Sea is one of these sites where a relatively thin first-year ice cover is constantly being changed by mixing of heat from below and stress exerted from the rapidly changing and intense winds.

This study presents mixed layer turbulence measurements obtained during two wintertime drift stations in August 2005 in the eastern Weddell Sea, close to the Maud Rise seamount. Turbulence in the boundary layer is found to be controlled by the drifting ice. Directly measured heat fluxes compare well with previous studies and are well estimated from the mixed layer temperatures and mixing. Heat fluxes are also found to roughly balance the conductive heat flux in the ice; hence, little freezing/melting was observed. The under-ice topography is estimated to be hydraulically very smooth; comparison with a steady 1-D model shows that these estimates are made too close to the ice-ocean interface to be representative for the entire ice floe. The main source and sink of turbulent kinetic energy are shear production and dissipation. Observations indicate that the dynamics of the under-ice boundary layer are influenced by a horizontal variability in mixed layer density and an increasing amount of open leads in the area.

Role of the upper ocean in the energy budget of Arctic sea ice during SHEBA

Shaw, W.J., T.P. Stanton, M.G. McPhee, J.H. Morison, and D.G. Martinson, "Role of the upper ocean in the energy budget of Arctic sea ice during SHEBA," J. Geophys. Res., 114, doi:10.1029/2008JC004991, 2009.

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12 Jun 2009

As part of the 1997–1998 Surface Heat Budget of the Arctic Experiment (SHEBA), a nearly yearlong record of upper ocean observations was obtained below a drifting ice camp in the Beaufort Gyre. A combination of observational and numerical modeling techniques are used to estimate heat fluxes across the under-ice ocean boundary layer. Over the Canada Basin, the upper pycnocline contained moderate heat, but strong stratification effectively insulated it from mixed layer turbulence.

Average resulting heat fluxes at the base of the mixed layer (Fpyc) and at the ocean-ice interface (F0) were small (0.3–1.2 and 0.2 W m-2, respectively). Over the Chukchi Borderlands, the presence of relatively warm and salty Pacific origin water increased upper pycnocline heat content and reduced stratification, which permitted moderate Fpyc and F0 (2.1–3.7 and 3.5 W m-2, respectively). Solar insolation was the dominant heat source during the final, summertime portion of the drift. During the heating period, Fpyc was relatively small (0.4–1.5 W m-2) while F0 was large (16.3 W m-2). The drift-averaged value of F0 was 7.6 W m-2. Energy budgets for the ice cover were constructed. The oceanic contribution to the budget during the portion of the drift over the Chukchi Borderlands, supported by entrainment of heat stored in the upper pycnocline, was responsible for a 15% reduction in ice growth. During the summer heating season, the F0 estimates were larger than the latent energy changes associated with basal melting.

Rapid change in freshwater content of the Arctic Ocean

McPhee, M.G., A. Proshutinsky, J.H. Morison, M. Steele, and M.B. Alkire, "Rapid change in freshwater content of the Arctic Ocean," Geophys. Res. Lett., 36, doi:10.1029/2009GL037525, 2009.

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21 May 2009

The dramatic reduction in minimum Arctic sea ice extent in recent years has been accompanied by surprising changes in the thermohaline structure of the Arctic Ocean, with potentially important impact on convection in the North Atlantic and the meridional overturning circulation of the world ocean. Extensive aerial hydrographic surveys carried out in March–April, 2008, indicate major shifts in the amount and distribution of fresh-water content (FWC) when compared with winter climatological values, including substantial freshening on the Pacific side of the Lomonosov Ridge. Measurements in the Canada and Makarov Basins suggest that total FWC there has increased by as much as 8,500 cubic kilometers in the area surveyed, effecting significant changes in the sea-surface dynamic topography, with an increase of about 75% in steric level difference from the Canada to Eurasian Basins, and a major shift in both surface geostrophic currents and freshwater transport in the Beaufort Gyre.

Ice-ocean turbulent exchange in the Arctic summer measured by an autonomous underwater vehicle

Hayes, D.R., and J. Morison, "Ice-ocean turbulent exchange in the Arctic summer measured by an autonomous underwater vehicle," Limnol. Oceanogr., 5, 2287-2308, doi:10.4319/lo.2008.53.5_part_2.2287, 2008.

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1 Dec 2008

The first-ever observed horizontal profiles of summertime ice–ocean boundary layer fluxes were obtained using vertical water velocity, temperature, and salinity collected by an Autonomous Underwater Vehicle during the Surface Heat Balance of the Arctic Ocean (SHEBA) experiment of 1998. Scalars and their vertical fluxes, as well as vertical stability, varied in the horizontal direction with correspondence to changes in the overlying surface. In early summer, fresh meltwater was trapped at the upper ice surface and only entered the ocean through leads. A highly stable fresh layer was formed in the SHEBA lead, which eventually grew to depths greater than the mean draft of the local first-year ice. Near the end of July, a storm removed this layer via shear-generated turbulence, supercritical hydraulic flow speeds, and ice divergence. The mixed layer freshened and deepened at this time. Particularly strong fluxes were observed under and downstream of rough, ridged ice, and properties changed rapidly with distance downstream of leads. The location and signs of the fluxes are suggestive of a mechanism of instability in which fresh surface water is forced under salty water downstream of leads and/or ridges. Simulations from a two-dimensional unsteady model suggest that both mechanical forcing from ice topography and a dynamic instability near downstream lead edges may enhance vertical mixing, particularly when ice velocity is large. The horizontal variability in interfacial fluxes observed at SHEBA may explain the difference between the observed melt rates and those calculated using a bulk relationship because this relationship may not adequately parameterize the large lateral heat fluxes at lead edges and basal heat fluxes under ridge keels.

Ensemble 1-year predictions of Arctic sea ice for the spring and summer of 2008

Zhang, J., M. Steele, R. Lindsay, A. Schweiger, J. Morison, "Ensemble 1-year predictions of Arctic sea ice for the spring and summer of 2008," Geophys. Res. Lett., 35, doi:10.1029/2008GL033244, 2008.

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22 Apr 2008

Ensemble predictions of arctic sea ice in spring and summer 2008 have been carried out using an ice-ocean model. The ensemble is constructed by using atmospheric forcing from 2001 to 2007 and the September 2007 ice and ocean conditions estimated by the model. The prediction results show that the record low ice cover and the unusually warm ocean surface waters in summer 2007 lead to a substantial reduction in ice thickness in 2008. Up to 1.2 m ice thickness reduction is predicted in a large area of the Canada Basin in both spring and summer of 2008, leading to extraordinarily thin ice in summer 2008. There is a 50% chance that both the Northern Sea Route and the Northwest Passage will be nearly ice free in September 2008. It is not likely there will be another precipitous decline in arctic sea ice extent such as seen in 2007, unless a new atmospheric forcing regime, significantly different from the recent past, occurs.

The return of Pacific waters to the upper layers of the central Arctic Ocean

Alkire, M.B., and K.K. Falkner, I. Rigor, M. Steele, and J. Morison, "The return of Pacific waters to the upper layers of the central Arctic Ocean," Deep-Sea Res. I, 54, 1509-1529, doi:10.1016/j.dsr.2007.06.004, 2007.

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1 Sep 2007

Temperature, salinity, and chemical measurements, including the nutrients silicic acid, nitrate, nitrite, ammonium, and phosphate, the oxygen isotopic composition of seawater, and barium concentrations were obtained from the central Arctic Ocean along transects radiating from the North Pole in early spring, 2000–2006. Stations that were reoccupied over this time period were grouped into five regions: from Ellesmere Island, (1) north along 70°W and (2) northwest along 90°W; near the North Pole, (3) on the Amundsen Basin flank and (4) directly over the Lomonosov Ridge; (5) through the Makarov Basin along 170–180°W. These regions had been shown by others to have undergone marked changes in water-mass assemblies in the early 1990s, but our time series tracer hydrographic data indicate a partial return of Pacific origin water within the mixed layer and the upper halocline layers beginning in 2003–2004. Back-trajectories derived from satellite-tracked ice buoys for these stations indicate that the upper levels of Pacific water in the central Arctic in 2004–2006 transited westward from the Bering Strait along the Siberian continental slope into the East Siberian Sea before entering the Transpolar Drift Stream (TPD). By 2004, the TPD shifted back from an alignment over the Alpha-Mendeleev Ridge toward the Lomonosov Ridge, as was characteristic prior to the early 1990s. At most stations occupied in 2006, a decrease in the Pacific influence was observed, both in the mixed layer and in the upper halocline, which suggests the Canadian branch of the TPD was shifting back toward North America. Clearly the system is more variable than has been previously appreciated.

Recent trends in Arctic Ocean mass distribution revealed by GRACE

Morison, J., J. Wahr, R. Kwok, and C. Peralta-Ferriz, "Recent trends in Arctic Ocean mass distribution revealed by GRACE," Geophys. Res. Lett., 34, doi:10.1029/2006GL029016, 2007.

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4 Apr 2007

Measurements of ocean bottom pressure by the Gravity Recovery and Climate Experiment (GRACE) and new in situ bottom pressure measurements confirm the accuracy and utility of GRACE measurements in the Arctic Ocean. They reveal a declining trend in bottom pressure that corresponds to mass changes due to decreasing upper ocean salinities near the North Pole and in the Makarov Basin. The spatial distribution and magnitude of these trends suggest the Arctic Ocean is reverting from the cyclonic state characterizing the 1990s to the anticyclonic state that was prevalent prior to the 1990s.

Relaxation of central Arctic Ocean hydrography to pre-1990s climatology

Morison, J., M. Steele, T. Kikuchi, K. Falkner, and W. Smethie, "Relaxation of central Arctic Ocean hydrography to pre-1990s climatology," Geophys. Res. Lett., 33, 10.1029/2006GL026826, 2006.

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8 Sep 2006

Upper ocean hydrography in the central Arctic Ocean has relaxed since 2000 to near-climatological conditions that pertained before the dramatic changes of the 1990s. The behavior of the anomalies of temperature and salinity in the central Arctic Ocean follow a first-order linear response to the AO with time constant of 5 years and a delay of 3 years.

One more step toward a warmer Arctic

Polyakov, I.V., A. Beszczynska, E.C. Carmack, I.A. Dmitrenko, E. Fahrbach, I.E. Frolov, R. Gerdes, E. Hansen, J. Holfort, V.V. Ivanov, M.A. Johnson, M. Karcher, F. Kauker, J. Morison, K.A. Orvik, U. Schauer, H.L. Simmons, O. Skagseth, V.T. Sokolov, M. Steele, L.A. Timokhov, D. Walsh, and J.E. Walsh, "One more step toward a warmer Arctic," Geophys. Res. Lett., 32, doi:10.1029/2005GL023740, 2005

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9 Sep 2005

This study was motivated by a strong warming signal seen in mooring-based and oceanographic survey data collected in 2004 in the Eurasian Basin of the Arctic Ocean. The source of this and earlier Arctic Ocean changes lies in interactions between polar and sub-polar basins. Evidence suggests such changes are abrupt, or pulse-like, taking the form of propagating anomalies that can be traced to higher-latitudes. For example, an anomaly found in 2004 in the eastern Eurasian Basin took ~1.5 years to propagate from the Norwegian Sea to the Fram Strait region, and additional ~4.5–5 years to reach the Laptev Sea slope. While the causes of the observed changes will require further investigation, our conclusions are consistent with prevailing ideas suggesting the Arctic Ocean is in transition towards a new, warmer state.

Dissolved oxygen extrema in the Arctic Ocean halocline from the North Pole to the Lincoln Sea

Falkner, K.K., M. Steele, R.A. Woodgate, J.H. Swift, K. Aagaard, and J. Morison, "Dissolved oxygen extrema in the Arctic Ocean halocline from the North Pole to the Lincoln Sea," Deep Sea Res. I, 52, 1138-1154, doi:10.1016/j.dsr.2005.01.007, 2005

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30 Jul 2005

Dissolved oxygen (O2) profiling by new generation sensors was conducted in the Arctic Ocean via aircraft during May 2003 as part of the North Pole Environmental Observatory (NPEO) and Freshwater Switchyard (SWYD) projects. At stations extending from the North Pole to the shelf off Ellesmere Island, such profiles display what appear to be various O2 maxima (with concentrations 70% of saturation or less) over depths of 70–110 m in the halocline, corresponding to salinity and temperature ranges of 33.3–33.9 and ~1.7 to ~1.5°C. The features appear to be widely distributed: Similar features based on bottle data were recently reported for a subset of the 1997–1998 SHEBA stations in the southern Canada Basin and in recent Beaufort Sea sensor profiles. Oxygen sensor data from August 2002 Chukchi Borderlands (CBL) and 1994 Arctic Ocean Section (AOS) projects suggest that such features arise from interleaving of shelf-derived, O2-depleted waters. This generates apparent oxygen maxima in Arctic Basin profiles that would otherwise trend more smoothly from near-saturation at the surface to lower concentrations at depth. For example, in the Eurasian Basin, relatively low O2 concentrations are observed at salinities of about 34.2 and 34.7. The less saline variant is identified as part of the lower halocline, a layer originally identified by a Eurasian Basin minimum in "NO," which, in the Canadian Basin, is reinforced by additional inputs. The more saline and thus denser variant appears to arise from transformations of Atlantic source waters over the Barents and/or Kara shelves. Additional low-oxygen waters are generated in the vicinity of the Chukchi Borderlands, from Pacific shelf water outflows that interleave with Eurasian waters that flow over the Lomonosov Ridge into the Makarov Basin and then into the Canada Basin. One such input is associated with the well-known silicate maximum that historically has been associated with a salinity of %u224833.1. Above that (322-depleted.

We propose that these low O2 waters influence the NPEO and SWYD profiles to varying extents in a manner reflective of the large-scale circulation. The patterns of halocline circulation we infer from the intrusive features defy a simple boundary-following cyclonic flow. These results demonstrate the value of the improved resolution made feasible with continuous O2 profiling. In the drive to better understand variability and change in the Arctic Ocean, deployment of appropriately calibrated CTD-O2 packages offers the promise of important new insights into circulation and ecosystem function.

Dissolved oxygen extrema in the Arctic Ocean halocline from the North Pole to the Lincoln Sea

Falkner, K.K., M. Steele, R.A. Woodgate, J.H. Swift, K. Aagaard, and J. Morison, "Dissolved oxygen extrema in the Arctic Ocean halocline from the North Pole to the Lincoln Sea," Eos Trans. AGU, 85(47), Abstract OS41A-0465, 2004.

15 Dec 2004

Circulation of summer Pacific halocline water in the Arctic Ocean

Steele, M., J. Morison, W. Ermold, M. Ortmeyer, and K. Shimada, "Circulation of summer Pacific halocline water in the Arctic Ocean," J. Geophys. Res., 109, C02027, doi:10.1029/2003JC002009, 2004.

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26 Feb 2004

We present an analysis of Arctic Ocean hydrographic and sea ice observations from the 1990s, with a focus on the circulation of water that originates in the North Pacific Ocean. Previous studies have shown the presence of two varieties of relatively warm "summer halocline water" in the vicinity of the Chukchi Sea, i.e., the relatively fresh Alaskan Coastal Water (ACW) and the relatively saltier summer Bering Sea Water (sBSW). Here we extend these studies by tracing the circulation of these waters downstream into the Arctic Ocean. We find that ACW is generally most evident in the southern Beaufort Gyre, while sBSW is strongest in the northern portion of the Beaufort Gyre and along the Transpolar Drift Stream. We find that this separation is most extreme during the early mid-1990s, when the Arctic Oscillation was at historically high index values. This leads us to speculate that the outflow to the North Atlantic Ocean (through the Canadian Archipelago and Fram Strait) may be similarly separated. As Arctic Oscillation index values fell during the later 1990s, ACW and sBSW began to overlap in their regions of influence. These changes are evident in the area north of Ellesmere Island, where the influence of sBSW is highly correlated, with a 3-year lag, with the Arctic Oscillation index. We also note the presence of winter Bering Sea Water (wBSW), which underlies the summer varieties. All together, this brings the number of distinct Pacific water types in our Arctic Ocean inventory to three: ACW, sBSW, and wBSW.

Ocean-to-ice heat flux at the North Pole environmental observatory

McPhee, M.G., T. Kikuchi, J.H. Morison, and T.P. Stanton, "Ocean-to-ice heat flux at the North Pole environmental observatory," Geophys. Res. Lett., 30, 10.1029/2003GL018580, 2003.

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24 Dec 2003

Data from drifting buoys deployed in April, 2002, as part of the North Pole Environmental Observatory project have been analysed to estimate ocean heat flux in the time period from 1 May 2002 to 11 Mar 2003. Prior to late January, the observatory remained in deep water, but subsequently drifted directly over the Yermak Plateau, a relatively shallow feature north of Svalbard. While over deep water, heat flux was dominated by storage and release of solar energy in the ocean boundary layer during summer. The most likely annual average value for 2002 was 2.6 W m-2, less than previous determinations in the western Arctic. Over Yermak Plateau, heat flux at the interface came from mixing of warmer water into the boundary layer from below. When the observatory was in water with depths less than 1200 m, the average heat flux was around 22 W m-2.

North Pole Environmental Observatory delivers early results

Morison, J.H., K. Aagaard, K.K. Falkner, K. Hatakeyama, R. Mortiz, J.E. Overland, D. Perovich, K. Shimada, M. Steele, T. Takizawa, and R. Woodgate, "North Pole Environmental Observatory delivers early results," Eos Trans. AGU, 83, 357-361, 2002.

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1 Aug 2002

Scientists have argued for a number of years that the Arctic may be a sensitive indicator of global change, but prior to the 1990s, conditions there were believed to be largely static. This has changed in the last 10 years. Decadal-scale changes have occurred in the atmosphere, in the ocean, and on land [Serreze et al., 2000]. Surface atmospheric pressure has shown a declining trend over the Arctic, resulting in a clockwise spin-up of the atmospheric polar vortex. In the 1990s, the Arctic Ocean circulation took on a more cyclonic character, and the temperature of Atlantic water in the Arctic Ocean was found to be the highest in 50 years of observation [Morison et al., 2000]. Sea-ice thickness over much of the Arctic decreased 43% in 1958–1976 and 1993–1997 [Rothrock et al., 1999].

Determining turbulent, vertical velocity, and fluxes of heat and salt with an autonomous underwater vehicle

Hayes, D.R., and J.H. Morison, "Determining turbulent, vertical velocity, and fluxes of heat and salt with an autonomous underwater vehicle," J. Atmos. Ocean. Techol., 19, 759-779, doi:10.1175/1520-0426(2002)019, 2002.

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1 May 2002

The authors show that vertical turbulent fluxes in the upper ocean can be measured directly with an autonomous underwater vehicle (AUV). A horizontal profile of vertical water velocity is obtained by applying a Kalman smoother to AUV motion data. The smoother uses a linearized model for vehicle motion and vehicle data such as depth, pitch, and pitch rate to produce an optimal estimate of the state of the system, which includes other vehicle variables and the vertical water velocity. Vertical water velocity estimated by applying the smoother to data from the autonomous microconductivity temperature vehicle (AMTV) is accurate at horizontal scales from three to several hundred meters, encompassing the energy-containing scales of most oceanic turbulence. The zero-lag covariances between vertical water velocity and concurrent measurements of temperature or salinity represent the heat and salt fluxes, respectively. The authors have measured horizontal profiles of turbulent fluxes with two different AUVs in three separate polar ocean experiments using this technique. Flux magnitudes and directions are reasonable and in general agreement with fixed turbulence sensors. With this technique, one can gather boundary layer data in inaccessible regions without disturbing or affecting the surface.

Surface heat budget of the Arctic Ocean

Uttal, T., and 27 others including R.E. Moritz, H.L. Stern, A. Heiberg, J.H. Morison, and R.W. Lindsay, "Surface heat budget of the Arctic Ocean," Bull. Amer. Meteor. Soc., 83, 255-275, 2002.

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1 Feb 2002

A summary is presented of the Surface Heat Budget of the Arctic Ocean (SHEBA) project, with a focus on the field experiment that was conducted from October 1997 to October 1998. The primary objective of the field work was to collect ocean, ice, and atmospheric datasets over a full annual cycle that could be used to understand the processes controlling surface heat exchanges—in particular, the ice-albedo feedback and cloud-radiation feedback. This information is being used to improve formulations of arctic ice-ocean-atmosphere processes in climate models and thereby improve simulations of present and future arctic climate. The experiment was deployed from an ice breaker that was frozen into the ice pack and allowed to drift for the duration of the experiment. This research platform allowed the use of an extensive suite of instruments that directly measured ocean, atmosphere, and ice properties from both the ship and the ice pack in the immediate vicinity of the ship. This summary describes the project goals, experimental design, instrumentation, and the resulting datasets. Examples of various data products available from the SHEBA project are presented.

Recent environmental changes in the Arctic: A review

Morison, J., K. Aagaard, and M. Steele, "Recent environmental changes in the Arctic: A review," Arctic, 53, 359-371, 2000.

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1 Dec 2000

Numerous recent observations indicate that the Arctic is undergoing a significant change. In the last decade, the hydrography of the Arctic Ocean has shifted, and the atmospheric circulation has undergone a change from the lower stratosphere to the surface. Typically the eastern Arctic Ocean, on the European side of the Lomonosov Ridge, is dominated by water of Atlantic origin. A cold halocline of varying thickness overlies the warmer Atlantic water and isolates it from the sea ice and surface mixed layer. The western Arctic Ocean, on the North American side of the Lomonosov Ridge, is characterized by an added layer of water from the Pacific immediately below the surface mixed layer. Data collected during several cruises from 1991 to 1995 indicate that in the 1990s the boundary between these eastern and western halocline types shifted from a position roughly parallel to the Lomonosov Ridge to near alignment with the Alpha and Mendeleyev Ridges. The Atlantic Water temperature has also increased, and the cold halocline has become thinner. The change has resulted in increased surface salinity in the Makarov Basin. Recent results suggest that the change also includes decreased surface salinity and greater summer ice melt in the Beaufort Sea. Atmospheric pressure fields and ice drift data show that the whole patterns of atmospheric pressure and ice drift for the early 1990s were shifted counterclockwise 40°-60° from earlier patterns. The shift in atmospheric circulation seems related to the Arctic Oscillation in the Northern Hemisphere atmospheric pressure pattern. The changes in the ocean circulation, ice drift, air temperatures, and permafrost can be explained as responses to the Arctic Oscillation, as can changes in air temperatures over the Russian Arctic.

Observational evidence of recent change in the northern high-latitude environment

Serreze, M.C., J.E. Walsh, F.S. Chapin III, T. Osterkamp, M. Dyurgerov, V. Romanovsky, W.C. Oechel, J.H. Morison, T. Zhang, and R.G. Barry, "Observational evidence of recent change in the northern high-latitude environment," Climatic Change, 46, 159-207, 2000.

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1 Mar 2000

Studies from a variety of disciplines document recent change in the northern high-latitude environment. Prompted by predictions of an amplified response of the Arctic to enhanced greenhouse forcing, we present asynthesis of these observations. Pronounced winter and spring warming over northern continents since about 1970 is partly compensated by cooling over the northern North Atlantic. Warming is also evident over the central Arctic Ocean. There is a downward tendency in sea ice extent, attended by warming and increased areal extent of the Arctic Ocean's Atlantic layer. Negative snow cover anomalies have dominated over both continents since the late 1980s and terrestrial precipitation has increased since 1900. Small Arctic glaciers have exhibited generally negative mass balances. While permafrost has warmed in Alaska and Russia, it has cooled in eastern Canada. There is evidence of increased plant growth, attended by greater shrub abundance and northward migration of the tree line. Evidence also suggests that the tundra has changed from a net sink to a net source of atmospheric carbon dioxide.Taken together, these results paint a reasonably coherent picture of change, but their interpretation as signals of enhanced greenhouse warming is open to debate. Many of the environmental records are either short, are of uncertain quality, or provide limited spatial coverage. The recent high-latitude warming is also no larger than the interdecadal temperature range during this century. Nevertheless, the general patterns of change broadly agree with model predictions. Roughly half of the pronounced recent rise in Northern Hemisphere winter temperatures reflects shifts in atmospheric circulation. However, such changes are not inconsistent with anthropogenic forcing and include generally positive phases of the North Atlantic and Arctic Oscillations and extratropical responses to the El-Nino Southern Oscillation. An anthropogenic effect is also suggested from interpretation of the paleoclimate record, which indicates that the 20th century Arctic is the warmest of the past 400 years.

Ocean heat flux in the central Weddell Sea during winter

McPhee, M.G., C. Kottmeier, and J.H. Morison, "Ocean heat flux in the central Weddell Sea during winter," J. Phys. Oceangr., 29, 1166-1179, 1999.

1 Jun 1999

In The News

Post-shutdown, UW Arctic research flights resume

UW News and Information, Hannah Hickey

After a couple of stressful weeks during the federal government shutdown, University of Washington researchers are back at work monitoring conditions near the North Pole. November has been busy for UW scientists studying winter storms, glacier melt and floating sea ice.

18 Nov 2013

Santa's workshop not flooded – but lots of melting in the Arctic

UW News and Information, Hannah Hickey

A dramatic image captured by a University of Washington monitoring buoy reportedly shows a lake at the North Pole. Researchers estimate the melt pond in the picture was just over 2 feet deep and a few hundred feet wide, which is not unusual to find on an Arctic ice floe in late July.

30 Jul 2013

Scientist on visible thinning of Arctic ice

ITV News

Dr. Jamie Morison has been visiting the North Pole for decades. He tells ITV News that Arctic ice is becoming noticeably thinner. (video interview)

11 Apr 2013

More News Items

Working in the world's most northerly science lab

ITV News, Lawrence McGinty

Scientist, equipment, and a news crew all boarded a helicopter for the flight between Camp Barneo on the arctic sea ice to the North Pole Environmental Observatory site some 40 miles away. Since 2000 APL-UW scientists have been deploying instruments into the Arctic Ocean beneath the ice to monitor as much as they can — water temperature, density and pressure.

11 Apr 2013

Scientists chuck instruments off planes into cracks in Arctic sea ice

NBCNews.com, Charles Q. Choi

As sea ice disappears in the Arctic Ocean, the U.S. Coast Guard is teaming with scientists to explore this new frontier by deploying scientific equipment through cracks in the ice from airplanes hundreds of feet in the air.

10 Oct 2012

UW scientists team with Coast Guard to explore ice-free Arctic Ocean

UW New and Information, Nancy Gohring

A new partnership has evolved for the Coast Guard and University of Washington scientists since disappearing Arctic ice has opened vast new frontiers.

2 Oct 2012

On Arctic ice and warmth, past and future

The New York Times, Andrew Revkin

Blogger Andrew Revkin writes about the resilience of the Arctic ecosystem. He cites work by APL-UW's James Morison and the North Pole Environmental Observatory project.

8 Aug 2011

Local scientist a global expert on air-sea-ice interaction

Yakima Herald-Republic, Mike Faulk

Polar scientist Jamie Morison comments on the work of his colleague Miles McPhee, who is regarded for his hard work developing models of Arctic climate and his initiative when performing research at ice camps in the Arctic region.

25 Jun 2011

Ten climate indicators in new report point to marked warming in last 30 years

UW Today, Sandra Hines

A NOAA climate report just out, that's different from other climate publications because it's based on observed data and not computer models, says 10 climate indicators all point to marked warming during the past three decades.

5 Aug 2010

Seattle icebreaker recommissioned by U.S. Coast Guard

KUOW Radio, Seattle, Josh Platis

The U.S. Coast Guard is beefing up its presence in the Arctic by reactivating the ice breaker Polar Star. She has been and will be used to carry polar researchers to the Arctic, and her role may be expanding.

19 Mar 2010

North Pole ever closer to having no ice

The Seattle Post-Intelligencer, Lisa Stiffler

For Arctic expert Ignatius Rigor, this is one bet he'd rather lose. He figured he was safe in his wager with fellow polar gurus that the area of ice would have shrunk to a record low this summer, beating last year's astonishing disappearing act.

16 Sep 2008

Cold reality: Polar bears on threatened list

The Seattle Post-Intelligencer, Jane Kay, San Francisco Chronicle

The No. 1 threat to polar bear survival is the growing disappearance of sea ice -- triggered in large part by climate change -- but the Bush administration wouldn't use the act to limit emissions on industrial sources such as coal plants or otherwise regulate greenhouse gases.

15 May 2008

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