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1. Author Correction: Subpolar North Atlantic western boundary density anomalies and the Meridional Overturning Circulation

Author

Li, F., Lozier, M. S., Bacon, S., Bower, A. S., Cunningham, S. A., de Jong, M. F., deYoung, B., Fraser, N., Fried, N., Han, G., Holliday, N. P., Holte, J., Houpert, L., Inall, M. E., Johns, W. E., Jones, S., Johnson, C., Karstensen, J., Le Bras, I. A., Lherminier, P., Lin, X., Mercier, H., Oltmanns, M., Pacini, A., Petit, T., Pickart, R. S., Rayner, D., Straneo, F., Thierry, V., Visbeck, M., Yashayaev, I., and Zhou, C.

Published
2022
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4. THE ICELAND GREENLAND SEAS PROJECT

Author

Renfrew, I. A., Pickart, R. S., Våge, K., Moore, G. W. K., Bracegirdle, T. J., Elvidge, A. D., Jeansson, E., Lachlan-Cope, T., McRaven, L. T., Papritz, L., Reuder, J., Sodemann, H., Terpstra, A., Waterman, S., Valdimarsson, H., Weiss, A., Almansi, M., Bahr, F., Brakstad, A., Barrell, C., Brooke, J. K., Brooks, B. J., Brooks, I. M., Brooks, M. E., Bruvik, E. M., Duscha, C., Fer, I., Golid, H. M., Hallerstig, M., Hessevik, I., Huang, J., Houghton, L., Jónsson, S., Jonassen, M., Jackson, K., Kvalsund, K., Kolstad, E. W., Konstali, K., Kristiansen, J., Ladkin, R., Lin, P., Macrander, A., Mitchell, A., Olafsson, H., Pacini, A., Payne, C., Palmason, B., Pérez-Hernández, M. D., Peterson, A. K., Petersen, G. N., Pisareva, M. N., Pope, J. O., Seidl, A., Semper, S., Sergeev, D., Skjelsvik, S., Søiland, H., Smith, D., Spall, M. A., Spengler, T., Touzeau, A., Tupper, G., Weng, Y., Williams, K. D., Yang, X., and Zhou, S.

Published
2019

5. Subpolar North Atlantic western boundary density anomalies and the Meridional Overturning Circulation

Author

Li, F., Lozier, M. S., Bacon, S., Bower, A. S., Cunningham, S. A., de Jong, M. F., deYoung, B., Fraser, N., Fried, N., Han, G., Holliday, N. P., Holte, J., Houpert, L., Inall, M. E., Johns, W. E., Jones, S., Johnson, C., Karstensen, J., Le Bras, I. A., Lherminier, P., Lin, X., Mercier, H., Oltmanns, M., Pacini, A., Petit, T., Pickart, R. S., Rayner, D., Straneo, F., Thierry, V., Visbeck, M., Yashayaev, I., and Zhou, C.

Published
2021
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7. Updating Lower North Atlantic Deep Water transports in the sub-polar North Atlantic

Author

Worthington, E., Johns, W., Bower, A., de Jong, F., Karstensen, J., Pickart, R., Dilmahamod, F., Fried, N., Koman, G., Pacini, A., and Hiang, J.

Abstract

The densest waters in the deep limb of the Atlantic meridional overturning circulation (AMOC) consist of overflow waters from the Nordic Seas: Denmark Strait Overflow Water (DSOW) and Iceland-Scotland Overflow Water (ISOW). These overflow waters are then substantially modified along their pathways by the entrainment of overlying intermediate waters and are eventually exported from the sub-polar gyre as Lower North Atlantic Deep Water. Since 2014, the OSNAP array has provided new insights into the sub-polar overturning circulation, including key boundary current arrays deployed across the Reykjanes Ridge, off East and West Greenland, and along the western side of the Labrador Sea.Here, using the OSNAP array data between 2014 and 2020, we quantify the mean transports of overflow waters along the deep boundary pathways, as well as recirculation within the Labrador Sea and Irminger Basin. Changes in the water properties of ISOW and DSOW as they advect around the deep subpolar gyre are also assessed. We further examine the traditional use of potential density of 27.88 kg/m3as the interface between ISOW and DSOW, and assess whether water mass boundary definitions need to change with increasing distance and entrainment along the deep circulation pathways., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023
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10. THE GREENLAND FLOW DISTORTION EXPERIMENT

Author

Renfrew, I. A., Moore, G. W. K., Kristjánsson, J. E., Ólafsson, H., Gray, S. L., Petersen, G. N., Bovis, K., Brown, P. R. A., Føre, I., Haine, T., Hay, C., Irvine, E. A., Lawrence, A., Ohigashi, T., Outten, S., Pickart, R. S., Shapiro, M., Sproson, D., Swinbank, R., Woolley, A., and Zhang, S.

Published
2008

11. An evaluation of surface meteorology and fluxes over the Iceland and Greenland Seas in ERA5 reanalysis: The impact of sea ice distribution

Author

Renfrew, I. A., Barrell, C., Elvidge, A. D., Brooke, J. K., Duscha, C., King, J.C., Kristiansen, J., Lachlan-Cope, T., Moore, G. W. K., Pickart, R. S., Reuder, J., Sandu, I., Sergeev, D., Terpstra, A., Våge, K., Weiss, A., Renfrew, I. A., Barrell, C., Elvidge, A. D., Brooke, J. K., Duscha, C., King, J.C., Kristiansen, J., Lachlan-Cope, T., Moore, G. W. K., Pickart, R. S., Reuder, J., Sandu, I., Sergeev, D., Terpstra, A., Våge, K., and Weiss, A.

Abstract

The Iceland and Greenland Seas are a crucial region for the climate system, being the headwaters of the lower limb of the Atlantic Meridional Overturning Circulation. Investigating the atmosphere–ocean–ice processes in this region often necessitates the use of meteorological reanalyses—a representation of the atmospheric state based on the assimilation of observations into a numerical weather prediction system. Knowing the quality of reanalysis products is vital for their proper use. Here we evaluate the surface‐layer meteorology and surface turbulent fluxes in winter and spring for the latest reanalysis from the European Centre for Medium‐Range Weather Forecasts, i.e., ERA5. In situ observations from a meteorological buoy, a research vessel, and a research aircraft during the Iceland–Greenland Seas Project provide unparalleled coverage of this climatically important region. The observations are independent of ERA5. They allow a comprehensive evaluation of the surface meteorology and fluxes of these subpolar seas and, for the first time, a specific focus on the marginal ice zone. Over the ice‐free ocean, ERA5 generally compares well to the observations of surface‐layer meteorology and turbulent fluxes. However, over the marginal ice zone, the correspondence is noticeably less accurate: for example, the root‐mean‐square errors are significantly higher for surface temperature, wind speed, and surface sensible heat flux. The primary reason for the difference in reanalysis quality is an overly smooth sea‐ice distribution in the surface boundary conditions used in ERA5. Particularly over the marginal ice zone, unrepresented variability and uncertainties in how to parameterize surface exchange compromise the quality of the reanalyses. A parallel evaluation of higher‐resolution forecast fields from the Met Office's Unified Model corroborates these findings.

Published
2021

12. Evolution of Denmark Strait overflow cyclones and their relationship to overflow surges

Author

Almansi, M., Haine, T. W. N., Gelderloos, R., Pickart, R. S., Almansi, M., Haine, T. W. N., Gelderloos, R., and Pickart, R. S.

Abstract

Mesoscale features present at the Denmark Strait sill regularly enhance the volume transport of the Denmark Strait overflow (DSO). They are important for the Atlantic Meridional Overturning Circulation and ultimately, for the global climate system. Using a realistic numerical model, we find new evidence of the causal relationship between overflow surges (i.e., mesoscale features associated with high‐transport events) and DSO cyclones observed downstream. Most of the cyclones form at the Denmark Strait sill during overflow surges and, because of potential vorticity conservation and stretching of the water column, grow as they move equatorward. A fraction of the cyclones form downstream of the sill, when anticyclonic vortices formed during high‐transport events start collapsing. Regardless of their formation mechanism, DSO cyclones weaken starting roughly 150 km downstream of the sill, and potential vorticity is only materially conserved during the growth phase.

Published
2020

13. An evaluation of surface meteorology and fluxes over the Iceland and Greenland Seas in ERA5 reanalysis: The impact of sea ice distribution

Author

Renfrew, I. A., primary, Barrell, C., additional, Elvidge, A. D., additional, Brooke, J. K., additional, Duscha, C., additional, King, J. C., additional, Kristiansen, J., additional, Cope, T. Lachlan, additional, Moore, G. W. K., additional, Pickart, R. S., additional, Reuder, J., additional, Sandu, I., additional, Sergeev, D., additional, Terpstra, A., additional, Våge, K., additional, and Weiss, A., additional

Published
2020
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14. Along‐Stream, Seasonal, and Interannual Variability of the North Icelandic Irminger Current and East Icelandic Current Around Iceland

Author

Casanova‐Masjoan, M., primary, Pérez‐Hernández, M. D., additional, Pickart, R. S., additional, Valdimarsson, H., additional, Ólafsdóttir, S. R., additional, Macrander, A., additional, Grisolía‐Santos, D., additional, Torres, D. J., additional, Jónsson, S., additional, Våge, K., additional, Lin, P., additional, and Hernández‐Guerra, A., additional

Published
2020
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17. A sea change in our view of overturning in the subpolar North Atlantic

Author

Lozier, S., Li, F., Bacon, S., Bahr, F., Bower, A., Cunningham, S., de Jong, F., de Steur, L., de Young, B., Fischer, J., Gary, S., Greenan, B., Holliday, N., Houk, A., Houpert, L., Inall, M., Johns, W., Johnson, H., Johnson, C., Karstensen, J., Koman, G., Le Bras, I., Lin, X., Mackay, N., Marshall, D., Mercier, H., Oltmanns, M., Pickart, R., Ramsey, A., Rayner, D., Straneo, F., Thierry, V., Torres, D., Williams, R., Wilson, C., Yang, J., and Zhao, J.

Abstract

To provide an observational basis for IPCC projections of a slowing Atlantic Meridional Overturning Circulation (MOC) in the 21st century, the Overturning in the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins, is largely responsible for overturning and its variability in the subpolar basin.

Published
2019

18. A sea change in our view of overturning in the subpolar North Atlantic

Author

Lozier, M. S., Li, F., Bacon, S., Bahr, F., Bower, A. S., Cunningham, S. A., De Jong, M. F., De Steur, L., Deyoung, B., Fischer, J., Gary, S. F., Greenan, B. J. W., Holliday, N. P., Houk, A., Houpert, L., Inall, M. E., Johns, W. E., Johnson, H. L., Johnson, C., Karstensen, J., Koman, G., Le Bras, I. A., Lin, X., Mackay, N., Marshall, D. P., Mercier, Herle, Oltmanns, M., Pickart, R. S., Ramsey, A. L., Rayner, D., Straneo, F., Thierry, Virginie, Torres, D. J., Williams, R. G., Wilson, C., Yang, J., Yashayaev, I., Zhao, J., Lozier, M. S., Li, F., Bacon, S., Bahr, F., Bower, A. S., Cunningham, S. A., De Jong, M. F., De Steur, L., Deyoung, B., Fischer, J., Gary, S. F., Greenan, B. J. W., Holliday, N. P., Houk, A., Houpert, L., Inall, M. E., Johns, W. E., Johnson, H. L., Johnson, C., Karstensen, J., Koman, G., Le Bras, I. A., Lin, X., Mackay, N., Marshall, D. P., Mercier, Herle, Oltmanns, M., Pickart, R. S., Ramsey, A. L., Rayner, D., Straneo, F., Thierry, Virginie, Torres, D. J., Williams, R. G., Wilson, C., Yang, J., Yashayaev, I., and Zhao, J.

Abstract

To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st century, the Overturning in the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins is largely responsible for overturning and its variability in the subpolar basin.

Published
2019
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21. A sea change in our view of overturning in the subpolar North Atlantic

Author

Lozier, M. S., primary, Li, F., additional, Bacon, S., additional, Bahr, F., additional, Bower, A. S., additional, Cunningham, S. A., additional, de Jong, M. F., additional, de Steur, L., additional, deYoung, B., additional, Fischer, J., additional, Gary, S. F., additional, Greenan, B. J. W., additional, Holliday, N. P., additional, Houk, A., additional, Houpert, L., additional, Inall, M. E., additional, Johns, W. E., additional, Johnson, H. L., additional, Johnson, C., additional, Karstensen, J., additional, Koman, G., additional, Le Bras, I. A., additional, Lin, X., additional, Mackay, N., additional, Marshall, D. P., additional, Mercier, H., additional, Oltmanns, M., additional, Pickart, R. S., additional, Ramsey, A. L., additional, Rayner, D., additional, Straneo, F., additional, Thierry, V., additional, Torres, D. J., additional, Williams, R. G., additional, Wilson, C., additional, Yang, J., additional, Yashayaev, I., additional, and Zhao, J., additional

Published
2019
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22. Variability and Redistribution of Heat in the Atlantic Water Boundary Current North of Svalbard

Author

Renner, A. H. H., Sundfjord, A., Janout, M. A., Ingvaldsen, R. B., Beszczynska‐Möller, A., Pickart, R. S., Pérez‐Hernández, M. D., Renner, A. H. H., Sundfjord, A., Janout, M. A., Ingvaldsen, R. B., Beszczynska‐Möller, A., Pickart, R. S., and Pérez‐Hernández, M. D.

Abstract

We quantify Atlantic Water heat loss north of Svalbard using year-long hydrographic and current records from three moorings deployed across the Svalbard Branch of the Atlantic Water boundary current in 2012–2013. The boundary current loses annually on average 16W m−2 during the eastward propagation along the upper continental slope. The largest vertical fluxes of >100W m−2 occur episodically in autumn and early winter. Episodes of sea ice imported from the north in November 2012 and February 2013 coincided with large ocean-to-ice heat fluxes, which effectively melted the ice and sustained open water conditions in the middle of the Arctic winter. Between March and early July 2013, a persistent ice cover-modulated air-sea fluxes. Melting sea ice at the start of the winter initiates a cold, up to 100-m-deep halocline separating the ice cover from the warm Atlantic Water. Semidiurnal tides dominate the energy over the upper part of the slope. The vertical tidal structure depends on stratification and varies seasonally, with the potential to contribute to vertical fluxes with shear-driven mixing. Further processes impacting the heat budget include lateral heat loss due to mesoscale eddies, and modest and negligible contributions of Ekman pumping and shelf break upwelling, respectively. The continental slope north of Svalbard is a key example regarding the role of ocean heat for the sea ice cover. Our study underlines the complexity of the ocean’s heat budget that is sensitive to the balance between oceanic heat advection, vertical fluxes, air-sea interaction, and the sea ice cover.

Published
2018

23. Overturning in the subpolar North Atlantic program: A new international ocean observing system

Author

Zika, J., Inall, M., Pillar, H., Zhao, J., Li, F., Lozier, M., Bower, A., Houpert, L., Yang, J., Bacon, S., Greenan, B., Holliday, N., Thierry, V., Marshall, D., Heimbach, P., Weller, R., Pickart, R., Lin, X., Cunningham, S., Karstensen, J., Wilson, C., Johnson, H., DeYoung, B., Gary, S., Williams, R., Straneo, F., Mackay, N., Johns, W., Fischer, J., Mercier, H., De Jong, M., De Steur, L., and Myers, P.

Published
2017
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28. Late spring nitrate distributions beneath the ice-covered northeastern Chukchi Shelf

Author

Arrigo, K. R., Mills, M. M., van Dijken, G. L., Lowry, K. E., Pickart, R., Schlitzer, Reiner, Arrigo, K. R., Mills, M. M., van Dijken, G. L., Lowry, K. E., Pickart, R., and Schlitzer, Reiner

Abstract

Measurements of late springtime nutrient concentrations in Arctic waters are relatively rare due to the extensive sea ice cover that makes sampling difficult. During the SUBICE cruise in May-June 2014, an extensive survey of hydrography and pre-bloom nutrient concentrations was conducted in the Chukchi Sea. Cold (< -1.5°C) winter water was prevalent throughout the Chukchi Sea shelf, and the water column was weakly stratified. Nitrate (NO3-) concentration averaged 12.6±1.92 µM in surface waters and 14.0±1.91 µM near the bottom and was significantly correlated with salinity. The highest NO3- concentrations were associated with winter water within the Central Channel flow path. NO3- concentrations were much reduced near the northern shelfbreak within the upper halocline waters of the Canada Basin and along the eastern side of the shelf near the Alaskan coast. Net community production (NCP), estimated as the difference in depth-integrated NO3- content between spring (this study) and summer (historical), varied from 28-38 g C m-2 a-1. This is much lower than previous NCP estimates using NO3- concentrations from the southeastern Bering Sea as a baseline. These results demonstrate the importance of using local profiles of NO3- measured as close to the beginning of the spring bloom as possible when estimating NCP.

Published
2017

32. Significant Biologically Mediated CO2 Uptake in the Pacific Arctic During the Late Open Water Season.

Author

Juranek, L., Takahashi, T., Mathis, J., and Pickart, R.

Subjects
CARBON dioxide, SEA ice, OCEAN, ECOSYSTEM dynamics, BIOGEOCHEMICAL cycles, SEAWATER
Abstract

Shifting baselines in the Arctic atmosphere‐sea ice‐ocean system have significant potential to alter biogeochemical cycling and ecosystem dynamics. In particular, the impact of increased open water duration on lower trophic level productivity and biological CO2 sequestration is poorly understood. Using high‐resolution observations of surface seawater dissolved O2/Ar and pCO2 collected in the Pacific Arctic in October 2011 and 2012, we evaluate spatial variability in biological metabolic status (autotrophy vs heterotrophy) as constrained by O2/Ar saturation (∆O2/Ar) as well as the relationship between net biological production and the sea‐air gradient of pCO2 (∆pCO2). We find a robust relationship between ∆pCO2 and ∆O2/Ar (correlation coefficient of −0.74 and −0.61 for 2011 and 2012, respectively), which suggests that biological production in the late open water season is an important determinant of the air‐sea CO2 gradient at a timeframe of maximal ocean uptake for CO2 in this region. Patchiness in biological production as indicated by ∆O2/Ar suggests spatially variable nutrient supply mechanisms supporting late season growth amidst a generally strongly stratified and nutrient‐limited condition. Plain Language Summary: The Arctic is experiencing rapid change. One of the most notable changes is an increase in the length of time coastal areas of the Arctic are ice‐free in summer, which may affect the growth patterns of microscopic marine plants at the bottom of the food chain in Arctic ecosystems. We investigate how the growth at the base of the food chain is responding to these sea ice changes in the late, "open water" period. To track growth, we measure the oxygen content of the surface ocean, which constrains the balance of growth and loss as marine plants photosynthesize and then are consumed and decomposed. We also relate the spatial patterns of net growth to the amount of carbon dioxide (CO2) gas dissolved in the surface ocean to evaluate the potential impact of biological activity on the uptake of this important greenhouse gas into the surface ocean. We find a surprising relationship between growth and areas of CO2 uptake by the ocean. This finding is important because it suggests that the biological community facilitates carbon dioxide uptake during a timeframe when previously growth would be inhibited by ice cover. Key Points: We evaluate biological carbon cycling in the Pacific Arctic during the late open water season∆O2/Ar and ΔpCO2 observations suggest an important role for late season biological activity toward maintaining an ocean carbon sinkHigh mesoscale variability in biological metabolism inferred from O2/Ar suggests localized and likely episodic nutrient supply [ABSTRACT FROM AUTHOR]

Published
2019
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33. State of the Climate in 2012

Author

Blunden, Jessica, Arndt, Derek S., Achberger, Christine, Ackerman, Stephen A., Albanil, Adelina, Alexander, P., Alfaro, Eric J., Allan, Rob, Alves, Lincoln M., Amador, Jorge A., Ambenje, Peter, Andrianjafinirina, Solonomenjanahary, Antonov, John, Aravequia, Jose A., Arendt, A., Arevalo, Juan, Ashik, I., Atheru, Zachary, Banzon, Viva, Baringer, Molly O., Barreira, Sandra, Barriopedro, David E., Beard, Grant, Becker, Andreas, Behrenfeld, Michael J., Bell, Gerald D., Benedetti, Angela, Bernhard, Germar, Berrisford, Paul, Berry, David I., Bhatt, U., Bidegain, Mario, Bindoff, Nathan, Bissolli, Peter, Blake, Eric S., Booneeady, Raj, Bosilovich, Michael, Box, J. E., Boyer, Tim, Braathen, Geir O., Bromwich, David H., Brown, R., Brown, L., Bruhwiler, Lori, Bulygina, Olga N., Burgess, D., Burrows, John, Calderon, Blanca, Camargo, Suzana J., Campbell, Jayaka, Cao, Y., Cappelen, J., Carrasco, Gualberto, Chambers, Don P., Chang A, L., Chappell, Petra, Chehade, Wissam, Cheliah, Muthuvel, Christiansen, Hanne H., Christy, John R., Ciais, Phillipe, Coelho, Caio A. S., Cogley, J. G., Colwell, Steve, Cross, J. N., Crouch, Jake, Cunningham, Stuart A., Dacic, Milan, Jeu, Richard A. M., Dekaa, Francis S., Demircan, Mesut, Derksen, C., Diamond, Howard J., Dlugokencky, Ed J., Dohan, Kathleen, Dolman, A. Johannes, Domingues, Catia M., Dong Shenfu, Dorigo, Wouter A., Drozdov, D. S., Duguay, Claude R., Dunn, Robert J. H., Duran-Quesada, Ana M., Dutton, Geoff S., Ehmann, Christian, Elkins, James W., Euscategui, Christian, Famiglietti, James S., Fang Fan, Fauchereau, Nicolas, Feely, Richard A., Fekete, Balazs M., Fenimore, Chris, Fioletov, Vitali E., Fogarty, Chris T., Fogt, Ryan L., Folland, Chris K., Foster, Michael J., Frajka-Williams, Eleanor, Franz, Bryan A., Frith, Stacey H., Frolov, I., Ganter, Catherine, Garzoli, Silvia, Geai, M. -L, Gerland, S., Gitau, Wilson, Gleason, Karin L., Gobron, Nadine, Goldenberg, Stanley B., Goni, Gustavo, Good, Simon A., Gottschalck, Jonathan, Gregg, Margarita C., Griffiths, Georgina, Grooss, Jens-Uwe, Guard, Charles Chip, Gupta, Shashi K., Hall, Bradley D., Halpert, Michael S., Harada, Yayoi, Hauri, C., Heidinger, Andrew K., Heikkila, Anu, Heim, Richard R., Heimbach, Patrick, Hidalgo, Hugo G., Hilburn, Kyle, Ho, Shu-Peng, Hobbs, Will R., Holgate, Simon, Hovsepyan, Anahit, Hu Zeng-Zhen, Hughes, P., Hurst, Dale F., Ingvaldsen, R., Inness, Antje, Jaimes, Ena, Jakobsson, Martin, James, Adamu I., Jeffries, Martin O., Johns, William E., Johnsen, Bjorn, Johnson, Gregory C., Johnson, Bryan, Jones, Luke T., Jumaux, Guillaume, Kabidi, Khadija, Kaiser, Johannes W., Kamga, Andre, Kang, Kyun-Kuk, Kanzow, Torsten O., Kao, Hsun-Ying, Keller, Linda M., Kennedy, John J., Key, J., Khatiwala, Samar, Pour, H. Kheyrollah, Kholodov, A. L., Khoshkam, Mahbobeh, Kijazi, Agnes, Kikuchi, T., Kim, B. -M, Kim, S. -J, Kimberlain, Todd B., Knaff, John A., Korshunova, Natalia N., Koskela, T., Kousky, Vernon E., Kramarova, Natalya, Kratz, David P., Krishfield, R., Kruger, Andries, Kruk, Michael C., Kumar, Arun, Lagerloef, Gary S. E., Lakkala, K., Lander, Mark A., Landsea, Chris W., Lankhorst, Matthias, Laurila, T., Lazzara, Matthew A., Lee, Craig, Leuliette, Eric, Levitus, Sydney, L Heureux, Michelle, Lieser, Jan, Lin, I-I, Liu, Y. Y., Liu, Y., Liu Hongxing, Liu Yanju, Lobato-Sanchez, Rene, Locarnini, Ricardo, Loeb, Norman G., Loeng, H., Long, Craig S., Lorrey, Andrew M., Luhunga, P., Lumpkin, Rick, Luo Jing-Jia, Lyman, John M., Macdonald, Alison M., Maddux, Brent C., Malekela, C., Manney, Gloria, Marchenko, S. S., Marengo, Jose A., Marotzke, Jochem, Marra, John J., Martinez-Gueingla, Rodney, Massom, Robert A., Mathis, Jeremy T., Mcbride, Charlotte, Mccarthy, Gerard, Mcvicar, Tim R., Mears, Carl, Meier, W., Meinen, Christopher S., Menendez, Melisa, Merrifield, Mark A., Mitchard, Edward, Mitchum, Gary T., Montzka, Stephen A., Morcrette, Jean-Jacques, Mote, Thomas, Muehle, Jens, Muehr, Bernhard, Mullan, A. Brett, Mueller, Rolf, Nash, Eric R., Nerem, R. Steven, Newlin, Michele L., Newman, Paul A., Ng Ongolo, H., Nieto, Juan Jose, Nishino, S., Nitsche, Helga, Noetzli, Jeannette, Oberman, N. G., Obregon, Andre, Ogallo, Laban A., Oludhe, Christopher S., Omar, Mohamed I., Overland, James, Oyunjargal, Lamjav, Parinussa, Robert M., Park, Geun-Ha, Park, E-Hyung, David Berry, Pasch, Richard J., Pascual-Ramirez, Reynaldo, Pelto, Mauri S., Penalba, Olga, Peng, L., Perovich, Don K., Pezza, Alexandre B., Phillips, David, Pickart, R., Pinty, Bernard, Pitts, Michael C., Purkey, Sarah G., Quegan, Shaun, Quintana, Juan, Rabe, B., Rahimzadeh, Fatemeh, Raholijao, Nirivololona, Raiva, I., Rajeevan, Madhavan, Ramiandrisoa, Voahanginirina, Ramos, Alexandre, Ranivoarissoa, Sahondra, Rayner, Nick A., Rayner, Darren, Razuveav, Vyacheslav N., Reagan, James, Reid, Phillip, Renwick, James, Revedekar, Jayashree, Richter-Menge, Jacqueline, Rivera, Ingrid L., Robinson, David A., Rodell, Matthew, Romanovsky, Vladimir E., Ronchail, Josyane, Rosenlof, Karen H., Sabine, Christopher L., Salvador, Mozar A., Sanchez-Lugo, Ahira, Santee, Michelle L., Sasgen, I., Sawaengphokhai, P., Sayouri, Amal, Scambos, Ted A., Schauer, U., Schemm, Jae, Schlosser, P., Schmid, Claudia, Schreck, Carl, Semiletov, Igor, Send, Uwe, Sensoy, Serhat, Setzer, Alberto, Severinghaus, Jeffrey, Shakhova, Natalia, Sharp, M., Shiklomanov, Nicolai I., Siegel, David A., Silva, Viviane B. S., Silva, Frabricio D. S., Sima, Fatou, Simeonov, Petio, Simmonds, I., Simmons, Adrian, Skansi, Maria, Smeed, David A., Smethie, W. M., Smith, Adam B., Smith, Cathy, Smith, Sharon L., Smith, Thomas M., Sokolov, V., Srivastava, A. K., Stackhouse, Paul W., Stammerjohn, Sharon, Steele, M., Steffen, Konrad, Steinbrecht, Wolfgang, Stephenson, Tannecia, Su, J., Svendby, T., Sweet, William, Takahashi, Taro, Tanabe, Raymond M., Taylor, Michael A., Tedesco, Marco, Teng, William L., Thepaut, Jean-Noel, Thiaw, Wassila M., Thoman, R., Thompson, Philip, Thorne, Peter W., Timmermans, M. -L, Tobin, Skie, Toole, J., Trewin, Blair C., Trigo, Ricardo M., Trotman, Adrian, Tschudi, M., Wal, Roderik S. W., Werf, Guido R., Vautard, Robert, Vazquez, J. L., Vieira, Goncalo, Vincent, Lucie, Vose, Russ S., Wagner, Wolfgang W., Wahr, John, Walsh, J., Wang Junhong, Wang Chunzai, Wang, M., Wang Sheng-Hung, Wang Lei, Wanninkhof, Rik, Weaver, Scott, Weber, Mark, Werdell, P. Jeremy, Whitewood, Robert, Wijffels, Susan, Wilber, Anne C., Wild, J. D., Willett, Kate M., Williams, W., Willis, Joshua K., Wolken, G., Wong, Takmeng, Woodgate, R., Worthy, D., Wouters, B., Wovrosh, Alex J., Xue Yan, Yamada, Ryuji, Yin Zungang, Yu Lisan, Zhang Liangying, Zhang Peiqun, Zhao Lin, Zhao, J., Zhong, W., Ziemke, Jerry, Zimmermann, S., ICOS-ATC (ICOS-ATC), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Repositório da Universidade de Lisboa

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, 13. Climate action, Photosynthetically active radiation, Climate, Dynamics (mechanics), Data_FILES, Environmental science, Fraction (chemistry), 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Remote sensing
Abstract

For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Nevertheless, other large-scale climate patterns and extreme weather events impacted various regions during the year. A negative phase of the Arctic Oscillation from mid-January to early February contributed to frigid conditions in parts of northern Africa, eastern Europe, and western Asia. A lack of rain during the 2012 wet season led to the worst drought in at least the past three decades for northeastern Brazil. Central North America also experienced one of its most severe droughts on record. The Caribbean observed a very wet dry season and it was the Sahel's wettest rainy season in 50 years. Overall, the 2012 average temperature across global land and ocean surfaces ranked among the 10 warmest years on record. The global land surface temperature alone was also among the 10 warmest on record. In the upper atmosphere, the average stratospheric temperature was record or near-record cold, depending on the dataset. After a 30-year warming trend from 1970 to 1999 for global sea surface temperatures, the period 2000-12 had little further trend. This may be linked to the prevalence of La Ni a-like conditions during the 21st century. Heat content in the upper 700 m of the ocean remained near record high levels in 2012. Net increases from 2011 to 2012 were observed at 700-m to 2000-m depth and even in the abyssal ocean below. Following sharp decreases in to the effects of La Ni a, sea levels rebounded to reach records highs in 2012. The increased hydrological cycle seen in recent years continued, with more evaporation in drier locations and more precipitation in rainy areas. In a pattern that has held since 2004, salty areas of the ocean surfaces and subsurfaces were anomalously salty on average, while fresher areas were anomalously fresh. Global tropical cyclone activity during 2012 was near average, with a total of 84 storms compared with the 1981-2010 average of 89. Similar to 2010 and 2011, the North Atlantic was the only hurricane basin that experienced above-normal activity. In this basin, Sandy brought devastation to Cuba and parts of the eastern North American seaboard. All other basins experienced either near-or below-normal tropical cyclone activity. Only three tropical cyclones reached Category 5 intensity-all in Bopha became the only storm in the historical record to produce winds greater than 130 kt south of 7 N. It was also the costliest storm to affect the Philippines and killed more than 1000 residents. Minimum Arctic sea ice extent in September and Northern Hemisphere snow cover extent in June both reached new record lows. June snow cover extent is now declining at a faster rate (-17.6% per decade) than September sea ice extent (-13.0% per decade). Permafrost temperatures reached record high values in northernmost Alaska. A new melt extent record occurred on 11-12 July on the Greenland ice sheet; 97% of the ice sheet showed some form of melt, four times greater than the average melt for this time of year. The climate in Antarctica was relatively stable overall. The largest maximum sea ice extent since records begain in 1978 was observed in September 2012. In the stratosphere, warm air led to the second smallest ozone hole in the past two decades. Even so, the springtime ozone layer above Antarctica likely will not return to its early 1980s state until about 2060. Following a slight decline associated with the global 2 emissions from fossil fuel combustion and cement production reached a record 9.5 +/- 0.5 Pg C in 2011 and a new record of 9.7 +/- 0.5 Pg C is estimated for 2012. Atmospheric CO2 concentrations increased by 2.1 ppm in 2012, to 392.6 ppm. In spring 2012, 2 concentration exceeded 400 ppm at 7 of the 13 Arctic observation sites. Globally, other greenhouse gases including methane and nitrous oxide also continued to rise in concentration and the combined effect now represents a 32% increase in radiative forcing over a 1990 baseline. Concentrations of most ozone depleting substances continued to fall.

Published
2013

34. Toward Improved Observing of the Rapidly Changing Arctic Ocean

Author

Proshutinsky, A., Toole, J., Krishfield, R., Plueddemann, A., Pickart, R., Ashijan, C., Timmermans, M-L., Perovich, D., Richer-Menge, J., Stanton, Timothy P.., Matrai, P., Lee, C., Morison, J., Steele, M., and Rigor, I.

Abstract

Arctic Observing Summit (April 30 – May 2, 2013, Vancouver, Canada); AON statement In order to observe and understand the Arctic Ocean and its response to climate change, the traditional approach of acquiring observations when and where the Arctic is accessible has to be enhanced with multi-faceted measurement systems operating autonomously to provide year-round information in real time. The major goal of such a network of autonomous sensors is to measure and monitor physical, chemical and biological parameters in the atmosphere, sea ice and ocean on at least daily intervals.

Published
2013

35. Significant Biologically Mediated CO2Uptake in the Pacific Arctic During the Late Open Water Season

Author

Juranek, L., Takahashi, T., Mathis, J., and Pickart, R.

Abstract

Shifting baselines in the Arctic atmosphere‐sea ice‐ocean system have significant potential to alter biogeochemical cycling and ecosystem dynamics. In particular, the impact of increased open water duration on lower trophic level productivity and biological CO2sequestration is poorly understood. Using high‐resolution observations of surface seawater dissolved O2/Ar and pCO2collected in the Pacific Arctic in October 2011 and 2012, we evaluate spatial variability in biological metabolic status (autotrophy vs heterotrophy) as constrained by O2/Ar saturation (∆O2/Ar) as well as the relationship between net biological production and the sea‐air gradient of pCO2(∆pCO2). We find a robust relationship between ∆pCO2and ∆O2/Ar(correlation coefficient of −0.74 and −0.61 for 2011 and 2012, respectively), which suggests that biological production in the late open water season is an important determinant of the air‐sea CO2gradient at a timeframe of maximal ocean uptake for CO2in this region. Patchiness in biological production as indicated by ∆O2/Arsuggests spatially variable nutrient supply mechanisms supporting late season growth amidst a generally strongly stratified and nutrient‐limited condition. The Arctic is experiencing rapid change. One of the most notable changes is an increase in the length of time coastal areas of the Arctic are ice‐free in summer, which may affect the growth patterns of microscopic marine plants at the bottom of the food chain in Arctic ecosystems. We investigate how the growth at the base of the food chain is responding to these sea ice changes in the late, “open water” period. To track growth, we measure the oxygen content of the surface ocean, which constrains the balance of growth and loss as marine plants photosynthesize and then are consumed and decomposed. We also relate the spatial patterns of net growth to the amount of carbon dioxide (CO2) gas dissolved in the surface ocean to evaluate the potential impact of biological activity on the uptake of this important greenhouse gas into the surface ocean. We find a surprising relationship between growth and areas of CO2uptake by the ocean. This finding is important because it suggests that the biological community facilitates carbon dioxide uptake during a timeframe when previously growth would be inhibited by ice cover. We evaluate biological carbon cycling in the Pacific Arctic during the late open water season∆O2/Arand ΔpCO2observations suggest an important role for late season biological activity toward maintaining an ocean carbon sinkHigh mesoscale variability in biological metabolism inferred from O2/Ar suggests localized and likely episodic nutrient supply

Published
2019
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36. Spatial distribution of air-sea heat fluxes over the sub-polar North Atlantic Ocean

Author

Moore, G. W. K., Renfrew, IA, and Pickart, R. S.

Abstract

On a variety of spatial and temporal scales, the energy transferred by air-sea heat and moisture fluxes plays an important role in both atmospheric and oceanic circulations. This is particularly true in the sub-polar North Atlantic Ocean, where these fluxes drive water-mass transformations that are an integral component of the Atlantic Meridional Overturning Circulation (AMOC). Here we use the ECMWF Interim Reanalysis to provide a high-resolution view of the spatial structure of the air-sea turbulent heat fluxes over the sub-polar North Atlantic Ocean. As has been previously recognized, the Labrador and Greenland Seas are areas where these fluxes are large during the winter months. Our particular focus is on the Iceland Sea region where, despite the fact that water-mass transformation occurs, the winter-time air-sea heat fluxes are smaller than anywhere else in the sub-polar domain. We attribute this minimum to a saddle point in the sea-level pressure field, that results in a reduction in mean surface wind speed, as well as colder sea surface temperatures associated with the regional ocean circulation. The magnitude of the heat fluxes in this region are modulated by the relative strength of the Icelandic and Lofoten Lows, and this leads to periods of ocean cooling and even ocean warming when, intriguingly, the sensible and latent heat fluxes are of opposite sign. This suggests that the air-sea forcing in this area has large-scale impacts for climate, and that even modest shifts in the atmospheric circulation could potentially impact the AMOC.

Published
2012

37. STATE OF THE CLIMATE IN 2011 Special Supplement to the Bulletin of the American Meteorological Society Vol. 93, No. 7, July 2012

Author

Arndt, D. S., Blunden, J., Willett, K. M., Dolman, A. J., Hall, B. D., Thorne, P. W., Gregg, M. C., Newlin, M. L., Xue, Y., Hu, Z., Kumar, A., Banzon, V., Smith, T. M., Rayner, N. A., Jeffries, M. O., Richter-Menge, J., Overland, J., Bhatt, U., Key, J., Liu, Y., Walsh, J., Wang, M., Fogt, R. L., Scambos, T. A., Wovrosh, A. J., Barreira, S., Sanchez-Lugo, A., Renwick, J. A., Thiaw, W. M., Weaver, S. J., Whitewood, R., Phillips, D., Achberger, C., Ackerman, S. A., Ahmed, F. H., Albanil-Encarnacion, A., Alfaro, E. J., Alves, L. M., Allan, R., Amador, J. A., Ambenje, P., Antoine, M. D., Antonov, J., Arevalo, J., Ashik, I., Atheru, Z., Baccini, A., Baez, J., Baringer, M. O., Barriopedro, D. E., Bates, J. J., Becker, A., Behrenfeld, M. J., Bell, G. D., Benedetti, A., Bernhard, G., Berrisford, P., Berry, D. I., Beszczynska-Moeller, A., Bhatt, U. S., Bidegain, M., Bieniek, P., Birkett, C., Bissolli, P., Blake, E. S., Boudet-Rouco, D., Box, J. E., Boyer, T., Braathen, G. O., Brackenridge, G. R., Brohan, P., Bromwich, D. H., Brown, L., Brown, R., Bruhwiler, L., Bulygina, O. N., Burrows, J., Calderon, B., Camargo, S. J., Cappellen, J., Carmack, E., Carrasco, G., Chambers, D. P., Christiansen, H. H., Christy, J., Chung, D., Ciais, P., Coehlo, C. A. S., Colwell, S., Comiso, J., Cretaux, J. F., Crouch, J., Cunningham, S. A., Jeu, R. A. M., Demircan, M., Derksen, C., Diamond, H. J., Dlugokencky, E. J., Dohan, K., Dorigo, W. A., Drozdov, D. S., Duguay, C., Dutton, E., Dutton, G. S., Elkins, J. W., Epstein, H. E., Famiglietti, J. S., Fanton D Andon, O. H., Feely, R. A., Fekete, B. M., Fenimore, C., Fernandez-Prieto, D., Fields, E., Fioletov, V., Folland, C., Foster, M. J., Frajka-Williams, E., Franz, B. A., Frey, K., Frith, S. H., Frolov, I., Frost, G. V., Ganter, C., Garzoli, S., Gitau, W., Gleason, K. L., Gobron, N., Goldenberg, S. B., Goni, G., Gonzalez-Garcia, I., Gonzalez-Rodriguez, N., Good, S. A., Goryl, P., Gottschalck, J., Gouveia, C. M., Griffiths, G. M., Grigoryan, V., Grooss, J. U., Guard, C., Guglielmin, M., Halpert, M. S., Heidinger, A. K., Heikkila, A., Heim, R. R., Hennon, P. A., Hidalgo, H. G., Hilburn, K., Ho, S. P., Hobbs, W. R., Holgate, S., Hook, S. J., Hovsepyan, A., Hu, Z. Z., Hugony, S., Hurst, D. F., Ingvaldsen, R., Itoh, M., Jaimes, E., Jeffries, M., Johns, W. E., Johnsen, B., Johnson, B., Johnson, G. C., Jones, L. T., Jumaux, G., Kabidi, K., Kaiser, J. W., Kang, K. K., Kanzow, T. O., Kao, H. Y., Keller, L. M., Kendon, M., Kennedy, J. J., Kervankiran, S., Khatiwala, S., Kholodov, A. L., Khoshkam, M., Kikuchi, T., Kimberlain, T. B., King, D., Knaff, J. A., Korshunova, N. N., Koskela, T., Kratz, D. P., Krishfield, R., Kruger, A., Kruk, M. C., Lagerloef, G., Lakkala, K., Lammers, R. B., Lander, M. A., Landsea, C. W., Lankhorst, M., Lapinel-Pedroso, B., Lazzara, M. A., Leduc, S., Lefale, P., Leon, G., Leon-Lee, A., Leuliette, E., Levitus, S., L Heureux, M., Lin, II, Liu, H. X., Liu, Y. J., Lobato-Sanchez, R., Locarnini, R., Loeb, N. G., Loeng, H., Long, C. S., Lorrey, A. M., Lumpkin, R., Myhre, C. L., Jing-Jia Luo, Lyman, J. M., Maccallum, S., Macdonald, A. M., Maddux, B. C., Manney, G., Marchenko, S. S., Marengo, J. A., Maritorena, S., Marotzke, J., Marra, J. J., Martinez-Sanchez, O., Maslanik, J., Massom, R. A., Mathis, J. T., Mcbride, C., Mcclain, C. R., Mcgrath, D., Mcgree, S., Mclaughlin, F., Mcvicar, T. R., Mears, C., Meier, W., Meinen, C. S., Menendez, M., Merchant, C., Merrifield, M. A., Miller, L., Mitchum, G. T., Montzka, S. A., Moore, S., Mora, N. P., Morcrette, J. J., Mote, T., Muhle, J., Mullan, A. B., Muller, R., Myhre, C., Nash, E. R., Nerem, R. S., Newman, P. A., Ngari, A., Nishino, S., Njau, L. N., Noetzli, J., Oberman, N. G., Obregon, A., Ogallo, L., Oludhe, C., Oyunjargal, L., Parinussa, R. M., Park, G. H., Parker, D. E., Pasch, R. J., Pascual-Ramirez, R., Pelto, M. S., Penalba, O., Perez-Suarez, R., Perovich, D., Pezza, A. B., Pickart, R., Pinty, B., Pinzon, J., Pitts, M. C., Pour, H. K., Prior, J., Privette, J. L., Proshutinsky, A., Quegan, S., Quintana, J., Rabe, B., Rahimzadeh, F., Rajeevan, M., Rayner, D., Raynolds, M. K., Razuvaev, V. N., Reagan, J., Reid, P., Revadekar, J., Rex, M., Rivera, I. L., Robinson, D. A., Rodell, M., Roderick, M. L., Romanovsky, V. E., Ronchail, J., Rosenlof, K. H., Rudels, B., Sabine, C. L., Santee, M. L., Sawaengphokhai, P., Sayouri, A., Schauer, U., Schemm, J., Schmid, C., Schreck, C., Semiletov, I., Send, U., Sensoy, S., Shakhova, N., Sharp, M., Shiklomanov, N. I., Shimada, K., Shin, J., Siegel, D. A., Simmons, A., Skansi, M., Sokolov, V., Spence, J., Srivastava, A. K., Stackhouse, P. W., Stammerjohn, S., Steele, M., Steffen, K., Steinbrecht, W., Stephenson, T., Stolarski, R. S., Sweet, W., Takahashi, T., Taylor, M. A., Tedesco, M., Thepaut, J. N., Thompson, P., Timmermans, M. L., Tobin, S., Toole, J., Trachte, K., Trewin, B. C., Trigo, R. M., Trotman, A., Tucker, C. J., Ulupinar, Y., Wal, R. S. W., Werf, G. R., Vautard, R., Votaw, G., Wagner, W. W., Wahr, J., Walker, D. A., Wang, C. Z., Wang, J. H., Wang, L., Wang, M. H., Wang, S. H., Wanninkhof, R., Weaver, S., Weber, M., Weingartner, T., Weller, R. A., Wentz, F., Wilber, A. C., Williams, W., Willis, J. K., Wilson, R. C., Wolken, G., Wong, T. M., Woodgate, R., Yamada, R., Yamamoto-Kawai, M., Yoder, J. A., Yu, L. S., Yueh, S., Zhang, L. Y., Zhang, P. Q., Zhao, L., Zhou, X. J., Zimmermann, S., Zubair, L., Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), National Oceanic and Atmospheric Administration (NOAA), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Space Technology Center, European Centre for Medium-Range Weather Forecasts (ECMWF), Climate Research Division [Toronto], Environment and Climate Change Canada, Earth and Space Research Institute [Seattle] (ESR), Department of Hydrology and Geo-Environmental Sciences [Amsterdam], Vrije Universiteit Amsterdam [Amsterdam] (VU), Vienna University of Technology (TU Wien), Instituto Dom Luiz, Universidade de Lisboa = University of Lisbon (ULISBOA), NOAA Earth System Research Laboratory (ESRL), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), Department of Earth System Science [Irvine] (ESS), University of California [Irvine] (UC Irvine), University of California (UC)-University of California (UC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), University of California Center for Hydrologic Modeling [Irvine] (UCCHM), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Boulder], University of Colorado [Boulder], Istituto Nazionale di Fisica Nucleare [Pisa] (INFN), Istituto Nazionale di Fisica Nucleare (INFN), NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML), University at Albany [SUNY], State University of New York (SUNY), Cooperative Institute for Meteorological Satellite Studies (CIMSS), University of Wisconsin-Madison-NASA-National Oceanic and Atmospheric Administration (NOAA), Peking University [Beijing], National Oceanography Centre [Southampton] (NOC), University of Southampton, NOAA National Environmental Satellite, Data, and Information Service (NESDIS), The University of Texas Medical Branch (UTMB), Institut für Umweltphysik [Bremen] (IUP), Universität Bremen, Department of Meteorology, University of Nairobi (UoN), Climate Prediction and Applications Centre (ICPAC), IGAD, Institute for Environment and Sustainability of the JRC, Partenaires INRAE, Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], Agricultural Information Institute (AII), Chinese Academy of Agricultural Sciences (CAAS), Woods Hole Oceanographic Institution (WHOI), Universitá degli Studi dell’Insubria = University of Insubria [Varese] (Uninsubria), Heilongjiang Institute of Science and Technology, Finnish Meteorological Institute (FMI), Universidad de Costa Rica (UCR), University Corporation for Atmospheric Research (UCAR), NOAA Center for Satellite Applications and Research (STAR), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA), ESRL Global Monitoring Laboratory [Boulder] (GML), Materials and structures Laboratory, Tokyo Institute of Technology [Tokyo] (TITECH), Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami [Coral Gables], Norwegian Radiation and Nuclear Safety Authority, Direction Interrégionale de Météo-France pour l'océan Indien (DIROI), Météo-France, Department of Earth Sciences [Oxford], University of Oxford, NASA Langley Research Center [Hampton] (LaRC), University of Hawai‘i [Mānoa] (UHM), Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Scripps Institution of Oceanography (SIO - UC San Diego), University of California [San Diego] (UC San Diego), Agroécologie [Dijon], Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Huazhong Agricultural University [Wuhan] (HZAU), NOAA National Weather Service (NWS), Department of Oceanography, Florida State University [Tallahassee] (FSU), Norwegian Institute for Air Research (NILU), Research Institute for Global Change (RIGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), NorthWest Research Associates (NWRA), Department of Physics [Socorro], New Mexico Institute of Mining and Technology [New Mexico Tech] (NMT), Ocean and Earth Science [Southampton], University of Southampton-National Oceanography Centre (NOC), Australian Antarctic Division (AAD), Australian Government, Department of the Environment and Energy, Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Massachusetts General Hospital [Boston], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Australian Research Council (ARC), Remote Sensing Systems [Santa Rosa] (RSS), Développement, institutions et analyses de long terme (DIAL), Université Paris Dauphine-PSL, Université Paris sciences et lettres (PSL), NOAA National Marine Fisheries Service (NMFS), University of California (UC), NMR Laboratory, Université de Mons, Université de Mons (UMons), NASA Goddard Space Flight Center (GSFC), Glaciology, Geomorphodynamics and Geochronology, Department of Geography [Zürich], Universität Zürich [Zürich] = University of Zurich (UZH)-Universität Zürich [Zürich] = University of Zurich (UZH), Chemistry Department [Massachusetts Institute of Technology], Massachusetts Institute of Technology (MIT), Nichols College Dudley, ERDC Cold Regions Research and Engineering Laboratory (CRREL), USACE Engineer Research and Development Center (ERDC), European Commission, Space Science and Engineering Center [Madison] (SSEC), University of Wisconsin-Madison, Lausanne University Hospital, Centro de Ciencias do Sistema Terrestre, Instituto Nacional de Pesquisas Espaciais (INPE), University of Sheffield, Hochschule Mannheim - University of Applied Sciences, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Indian Institute of Tropical Meteorology (IITM), Ministry of Earth Sciences [India], Woods Hole Research Center, Department of Earth and Environment [Boston], Boston University [Boston] (BU), Centre for Australian Weather and Climate Research (CAWCR), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Génétique et Ecologie des Virus, Génétique des Virus et Pathogénèse des Maladies Virales, Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), Department of Botany and Plant Pathology, Oregon State University (OSU), Ctr Ecol & Hydrol, Bangor, Environm Ctr Wales, Biospherical Instruments Inc., Processus de la variabilité climatique tropicale et impacts (PARVATI), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7), Instituto Uruguayo de Meteorología, Javier Barrios Amorín 1488, CP 11200, Montevideo, Uruguay, Science Systems and Applications, Inc. [Hampton] (SSAI), National Snow and Ice Data Center (NSIDC), Naval Postgraduate School (NPS), University of California [Berkeley] (UC Berkeley), Centre de physique moléculaire optique et hertzienne (CPMOH), Université Sciences et Technologies - Bordeaux 1 (UB)-Centre National de la Recherche Scientifique (CNRS), CYRIC, Tohoku University [Sendai], The University of Tennessee [Knoxville], Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, The University Centre in Svalbard (UNIS), Institute of Arctic Alpine Research [University of Colorado Boulder] (INSTAAR), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Meteorologisches Observatorium Hohenpeißenberg (MOHp), Deutscher Wetterdienst [Offenbach] (DWD), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Universidade de Lisboa (ULISBOA), University of California [Irvine] (UCI), University of California-University of California, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Universitá degli Studi dell’Insubria, University of Costa Rica, Météo France [Sainte-Clotilde], Météo France, University of Oxford [Oxford], Scripps Institution of Oceanography (SIO), Huazhong Agricultural University, University of California, NMR and Molecular Imaging Laboratory [Mons], University of Mons [Belgium] (UMONS), Lausanne University Hospital [Switzerland], Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris Diderot - Paris 7 (UPD7), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Berkeley University of California (UC BERKELEY), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, and Institute of Arctic and Alpine Research (INSTAAR)

Subjects
[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

International audience; Large-scale climate patterns influenced temperature and weather patterns around the globe in 2011. In particular, a moderate-to-strong La Nina at the beginning of the year dissipated during boreal spring but reemerged during fall. The phenomenon contributed to historical droughts in East Africa, the southern United States, and northern Mexico, as well the wettest two-year period (2010-11) on record for Australia, particularly remarkable as this follows a decade-long dry period. Precipitation patterns in South America were also influenced by La Nina. Heavy rain in Rio de Janeiro in January triggered the country's worst floods and landslides in Brazil's history. The 2011 combined average temperature across global land and ocean surfaces was the coolest since 2008, but was also among the 15 warmest years on record and above the 1981-2010 average. The global sea surface temperature cooled by 0.1 degrees C from 2010 to 2011, associated with cooling influences of La Nina. Global integrals of upper ocean heat content for 2011 were higher than for all prior years, demonstrating the Earth's dominant role of the oceans in the Earth's energy budget. In the upper atmosphere, tropical stratospheric temperatures were anomalously warm, while polar temperatures were anomalously cold. This led to large springtime stratospheric ozone reductions in polar latitudes in both hemispheres. Ozone concentrations in the Arctic stratosphere during March were the lowest for that period since satellite records began in 1979. An extensive, deep, and persistent ozone hole over the Antarctic in September indicates that the recovery to pre-1980 conditions is proceeding very slowly. Atmospheric carbon dioxide concentrations increased by 2.10 ppm in 2011, and exceeded 390 ppm for the first time since instrumental records began. Other greenhouse gases also continued to rise in concentration and the combined effect now represents a 30% increase in radiative forcing over a 1990 baseline. Most ozone depleting substances continued to fall. The global net ocean carbon dioxide uptake for the 2010 transition period from El Nino to La Nina, the most recent period for which analyzed data are available, was estimated to be 1.30 Pg C yr(-1), almost 12% below the 29-year long-term average. Relative to the long-term trend, global sea level dropped noticeably in mid-2010 and reached a local minimum in 2011. The drop has been linked to the La Nina conditions that prevailed throughout much of 2010-11. Global sea level increased sharply during the second half of 2011. Global tropical cyclone activity during 2011 was well-below average, with a total of 74 storms compared with the 1981-2010 average of 89. Similar to 2010, the North Atlantic was the only basin that experienced above-normal activity. For the first year since the widespread introduction of the Dvorak intensity-estimation method in the 1980s, only three tropical cyclones reached Category 5 intensity level-all in the Northwest Pacific basin. The Arctic continued to warm at about twice the rate compared with lower latitudes. Below-normal summer snowfall, a decreasing trend in surface albedo, and above-average surface and upper air temperatures resulted in a continued pattern of extreme surface melting, and net snow and ice loss on the Greenland ice sheet. Warmer-than-normal temperatures over the Eurasian Arctic in spring resulted in a new record-low June snow cover extent and spring snow cover duration in this region. In the Canadian Arctic, the mass loss from glaciers and ice caps was the greatest since GRACE measurements began in 2002, continuing a negative trend that began in 1987. New record high temperatures occurred at 20 m below the land surface at all permafrost observatories on the North Slope of Alaska, where measurements began in the late 1970s. Arctic sea ice extent in September 2011 was the second-lowest on record, while the extent of old ice (four and five years) reached a new record minimum that was just 19% of normal. On the opposite pole, austral winter and spring temperatures were more than 3 degrees C above normal over much of the Antarctic continent. However, winter temperatures were below normal in the northern Antarctic Peninsula, which continued the downward trend there during the last 15 years. In summer, an all-time record high temperature of -12.3 degrees C was set at the South Pole station on 25 December, exceeding the previous record by more than a full degree. Antarctic sea ice extent anomalies increased steadily through much of the year, from briefly setting a record low in April, to well above average in December. The latter trend reflects the dispersive effects of low pressure on sea ice and the generally cool conditions around the Antarctic perimeter.

Published
2012

40. [the Arctic] Ocean temperature and salinity [in: State of the Climate in 2013]

Author

Timmermans, M.-L., Ashik, I., Frolov, I., Ha, H. K., Ingvaldsen, R., Kikuchi, T., Kim, T. W., Krishfield, R., Loeng, H., Nishino, S., Pickart, R., Polyakov, I., Rabe, Benjamin, Schauer, Ursula, Schlosser, P., Smethie, W. M., Sokolov, V., Steele, M., Toole, J., Williams, W., Woodgate, R., Zimmerman, S., Timmermans, M.-L., Ashik, I., Frolov, I., Ha, H. K., Ingvaldsen, R., Kikuchi, T., Kim, T. W., Krishfield, R., Loeng, H., Nishino, S., Pickart, R., Polyakov, I., Rabe, Benjamin, Schauer, Ursula, Schlosser, P., Smethie, W. M., Sokolov, V., Steele, M., Toole, J., Williams, W., Woodgate, R., and Zimmerman, S.

Published
2014

42. The Labrador Sea Deep Convection Experiment data collection

Author

Krahmann, Gerd, Visbeck, Martin, Smethie, W., D'Asaro, E. A., Rhines, P. B., Clarke, R. A., Lazier, J., Davis, R. E., Niiler, P. P., Guest, P. S., Meincke, J., Moore, K. G. W., Pickart, R. S., Brechner Owens, W., Prater, M. D., Renfrew, I. A., and Schott, Friedrich

Abstract

Between 1996 and 1998, a concerted effort was made to study the deep open ocean convection in the Labrador Sea. Both in situ observations and numerical models were employed with close collaboration between the researchers in the fields of physical oceanography, boundary layer meteorology, and climate. A multitude of different methods were used to observe the state of ocean and atmosphere and determine the exchange between them over the experiment's period. The Labrador Sea Deep Convection Experiment data collection aims to assemble the observational data sets in order to facilitate the exchange and collaboration between the various projects and new projects for an overall synthesis. A common file format and a browsable inventory have been used so as to simplify the access to the data.

Published
2003

43. [the Arctic] Ocean temperature and salinity [in: State of the Climate in 2012]

Author

Timmermans, M.-L., Ashik, I., Cao, Y., Frolov, I., Ingvaldsen, R., Kikuchi, T., Krishfield, R., Loeng, H., Nishino, S., Pickart, R., Rabe, Benjamin, Semiletov, I., Schauer, Ursula, Schlosser, P., Shakhova, N., Smethie, W. M., Sokolov, V., Steele, M., Su, J., Toole, J., Williams, W., Woodgate, R., Zhao, J., Zhong, W., Zimmerman, S., Timmermans, M.-L., Ashik, I., Cao, Y., Frolov, I., Ingvaldsen, R., Kikuchi, T., Krishfield, R., Loeng, H., Nishino, S., Pickart, R., Rabe, Benjamin, Semiletov, I., Schauer, Ursula, Schlosser, P., Shakhova, N., Smethie, W. M., Sokolov, V., Steele, M., Su, J., Toole, J., Williams, W., Woodgate, R., Zhao, J., Zhong, W., and Zimmerman, S.

Published
2013

44. Mean structure and dynamics of the shelfbreak jet in the Middle Atlantic Bight during fall and winter

Author

Fratantoni, P. S., Pickart, R. S., Torres, D. J., and Alberto Scotti

Abstract

Using a collection of high-resolution shipboard acoustic Doppler current profiler (ADCP) velocity sections that cross the Middle Atlantic Bight shelfbreak jet near 70°W, the mean structure of the frontal jet is described and the dominant modes of variability of the jet are examined. A mean section is constructed in a translating coordinate frame whose origin tracks the instantaneous position of the core of the jet, thereby minimizing variability associated with the lateral meandering of the current. The mean jet so constructed extends to the bottom, tilting onshore with depth, with near-bottom flow exceeding 0.10 m s-1. The corresponding cross-stream flow reveals a clear pattern of convergence that extends along the tilted axis of the jet, with enhanced convergence both near the surface and near the bottom. This convergence is largely attributed to the locally convergent topography and is shown to drive an ageostrophic circulation dominated by downwelling at, and offshore of, the jet core. The collection of ADCP sections also suggests a previously undetedted mode of variability, whereby the jet systematically fluctuates between a convergent, bottom-reaching state and a surface-trapped state with weaker cross-stream velocities. This variability is associated with significant variations in the southwestward transport of the jet and does not seem to be related to simple meandering of the current.

Published
2001
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45. Observational program tracks Arctic Ocean transition to a warmer state

Author

Polyakov, I., Timokhov, L., Dmitrenko, I., Ivanov, V., Simmons, H., Beszcynska-Moeller, A., Dickson, R., Fahrbach, E., Fortier, L., Gascard, J., Hoeleman, J., Holliday, N.P., Hansen, E., Mauritzen, C., Piechura, J., Pickart, R., Schauer, U., Steele, M., Walczowski, W., Polyakov, I., Timokhov, L., Dmitrenko, I., Ivanov, V., Simmons, H., Beszcynska-Moeller, A., Dickson, R., Fahrbach, E., Fortier, L., Gascard, J., Hoeleman, J., Holliday, N.P., Hansen, E., Mauritzen, C., Piechura, J., Pickart, R., Schauer, U., Steele, M., and Walczowski, W.

Published
2007

46. Observational program tracks Arctic Ocean transition to a warmer state

Author

Polyakov, I. R., Timokhov, L., Dmitrenko, I., Ivanov, V., Simmons, H., Beszczynska-Möller, Agnieszka, Dickson, R., Fahrbach, Eberhard, Fortier, L., Gascard, J.-C., Hölemann, Jens, Holliday, N. P., Hansen, E., Mauritzen, C., Piechura, J., Pickart, R., Schauer, Ursula, Steele, M., Walczowski, W., Polyakov, I. R., Timokhov, L., Dmitrenko, I., Ivanov, V., Simmons, H., Beszczynska-Möller, Agnieszka, Dickson, R., Fahrbach, Eberhard, Fortier, L., Gascard, J.-C., Hölemann, Jens, Holliday, N. P., Hansen, E., Mauritzen, C., Piechura, J., Pickart, R., Schauer, Ursula, Steele, M., and Walczowski, W.

Published
2007

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