Early 20th Century Arctic Warming Intensified by Pacific and Atlantic Multidecadal Variability

NASA Astrophysics Data System (ADS)

Tokinaga, H.; Xie, S. P.; Mukougawa, H.

2017-12-01

We investigate the influence of Pacific and Atlantic multidecadal variability on the Arctic temperature, with a particular focus on the early 20th century Arctic warming. Arctic surface air temperature increased rapidly over the early 20th century, at rates comparable to those of recent decades despite much weaker greenhouse gas forcing than at present. We find that the concurrent phase shift of Pacific and Atlantic multidecadal variability is the major driver for the early 20th century Arctic warming. Atmospheric model simulations reproduce the early Arctic warming when the interdecadal variability of sea surface temperature (SST) is properly prescribed. The early Arctic warming is associated with the cold-to-warm phase shifts of Atlantic and Pacific multidecadal variability modes, a SST pattern reminiscent of the positive phase of the Pacific decadal and Atlantic multidecadal oscillations. The extratropical North Atlantic and North Pacific SST warming strengthens surface westerly winds over northern Eurasia, intensifying the warming there. The equatorial Pacific warming deepens the Aleutian low, advecting warm air to the North American Arctic. Coupled ocean-atmosphere simulations support the constructive intensification of Arctic warming by a concurrent, cold-to-warm phase shift of the Pacific and Atlantic multidecadal variability. Our results aid attributing the historical Arctic warming and thereby constrain the amplified warming projected for this important region.

50 CFR Table 47a to Part 679 - Percent of the AFA Catcher/Processor Sector's Pollock Allocation, Numbers of Chinook Salmon Used...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 371 1.65 Arctic Fjord 940866 3396 4.46 293 68 361 1.60 Northern Glacier 663457 661 3.12 205 48 253 1.12 Pacific Glacier 933627 3357 5.06 332 77 409 1.82 Highland Light 577044 3348 5.14 337 79 416 1.85...

50 CFR Table 47a to Part 679 - Percent of the AFA Catcher/Processor Sector's Pollock Allocation, Numbers of Chinook Salmon Used...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 371 1.65 Arctic Fjord 940866 3396 4.46 293 68 361 1.60 Northern Glacier 663457 661 3.12 205 48 253 1.12 Pacific Glacier 933627 3357 5.06 332 77 409 1.82 Highland Light 577044 3348 5.14 337 79 416 1.85...

50 CFR Table 47a to Part 679 - Percent of the AFA Catcher/Processor Sector's Pollock Allocation, Numbers of Chinook Salmon Used...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 371 1.65 Arctic Fjord 940866 3396 4.46 293 68 361 1.60 Northern Glacier 663457 661 3.12 205 48 253 1.12 Pacific Glacier 933627 3357 5.06 332 77 409 1.82 Highland Light 577044 3348 5.14 337 79 416 1.85...

Trends and variability of cloud fraction cover in the Arctic, 1982-2009

NASA Astrophysics Data System (ADS)

Boccolari, Mauro; Parmiggiani, Flavio

2018-05-01

Climatology, trends and variability of cloud fraction cover (CFC) data over the Arctic (north of 70°N), were analysed over the 1982-2009 period. Data, available from the Climate Monitoring Satellite Application Facility (CM SAF), are derived from satellite measurements by AVHRR. Climatological means confirm permanent high CFC values over the Atlantic sector during all the year and during summer over the eastern Arctic Ocean. Lower values are found in the rest of the analysed area especially over Greenland and the Canadian Archipelago, nearly continuously during all the months. These results are confirmed by CFC trends and variability. Statistically significant trends were found during all the months over the Greenland Sea, particularly during the winter season (negative, less than -5 % dec -1) and over the Beaufort Sea in spring (positive, more than +5 % dec -1). CFC variability, investigated by the Empirical Orthogonal Functions, shows a substantial "non-variability" in the Northern Atlantic Ocean. Statistically significant correlations between CFC principal components elements and both the Pacific Decadal Oscillation index and Pacific North America patterns are found.

Early 20th-century Arctic warming intensified by Pacific and Atlantic multidecadal variability

NASA Astrophysics Data System (ADS)

Tokinaga, Hiroki; Xie, Shang-Ping; Mukougawa, Hitoshi

2017-06-01

With amplified warming and record sea ice loss, the Arctic is the canary of global warming. The historical Arctic warming is poorly understood, limiting our confidence in model projections. Specifically, Arctic surface air temperature increased rapidly over the early 20th century, at rates comparable to those of recent decades despite much weaker greenhouse gas forcing. Here, we show that the concurrent phase shift of Pacific and Atlantic interdecadal variability modes is the major driver for the rapid early 20th-century Arctic warming. Atmospheric model simulations successfully reproduce the early Arctic warming when the interdecadal variability of sea surface temperature (SST) is properly prescribed. The early 20th-century Arctic warming is associated with positive SST anomalies over the tropical and North Atlantic and a Pacific SST pattern reminiscent of the positive phase of the Pacific decadal oscillation. Atmospheric circulation changes are important for the early 20th-century Arctic warming. The equatorial Pacific warming deepens the Aleutian low, advecting warm air into the North American Arctic. The extratropical North Atlantic and North Pacific SST warming strengthens surface westerly winds over northern Eurasia, intensifying the warming there. Coupled ocean-atmosphere simulations support the constructive intensification of Arctic warming by a concurrent, negative-to-positive phase shift of the Pacific and Atlantic interdecadal modes. Our results aid attributing the historical Arctic warming and thereby constrain the amplified warming projected for this important region.

Evidence for Pacific Climate Regime Shifts as Preserved in a Southeast Alaska Ice Core

NASA Astrophysics Data System (ADS)

Porter, S. E.; Mosley-Thompson, E. S.; Thompson, L. G.

2012-12-01

Climate modes emanating from the Pacific sector have far-reaching effects across the globe. The El Niño/Southern Oscillation (ENSO) reflects anomalies in the sea surface temperature and pressure fields over the tropical Pacific, but climate implications from these anomalies extend to monsoon regions of Asia to North America and even Europe. The Pacific Decadal Oscillation (PDO) explains sea surface temperature anomalies in the North Pacific sector and influences the long-term behavior of the ENSO cycle as well as the storm track over North America expressed as the Pacific/North American Pattern (PNA). The impacts of both climate change and drastically reduced Arctic sea ice cover on these teleconnection patterns are poorly understood, and with little knowledge about their past behavior, predicting the changes in these climate modes is extremely difficult. An ice core from the col between Mt. Bona and Mt. Churchill in southeast Alaska provides an opportunity to examine the PDO prior to both the start of instrumental records and the more recent effects of anthropogenic climate change. The Bona-Churchill records of isotopic, dust, and chemical composition are compared to nearby meteorological station and 20th century reanalysis data to evaluate their strength as climate recorders. Climate indices such as the PDO and PNA, along with indices created to describe the strength and position of the Aleutian Low and Siberian High, are incorporated into the analysis to determine if proxy relationships are altered under different climate regimes. Satellite records of sea ice extent within the Sea of Okhotsk and the Bering Sea, when compared to the Bona-Churchill data, show a distinct change in behavior in the mid-1990s possibly in response to the temporary negative shift in the PDO. This behavioral shift is explored and placed into a broader climate context to determine whether similar events have occurred in the past or if this shift is unique to a rapidly warming Arctic.

Early 20th-century Arctic warming intensified by Pacific and Atlantic multidecadal variability

PubMed Central

Tokinaga, Hiroki; Xie, Shang-Ping; Mukougawa, Hitoshi

2017-01-01

With amplified warming and record sea ice loss, the Arctic is the canary of global warming. The historical Arctic warming is poorly understood, limiting our confidence in model projections. Specifically, Arctic surface air temperature increased rapidly over the early 20th century, at rates comparable to those of recent decades despite much weaker greenhouse gas forcing. Here, we show that the concurrent phase shift of Pacific and Atlantic interdecadal variability modes is the major driver for the rapid early 20th-century Arctic warming. Atmospheric model simulations successfully reproduce the early Arctic warming when the interdecadal variability of sea surface temperature (SST) is properly prescribed. The early 20th-century Arctic warming is associated with positive SST anomalies over the tropical and North Atlantic and a Pacific SST pattern reminiscent of the positive phase of the Pacific decadal oscillation. Atmospheric circulation changes are important for the early 20th-century Arctic warming. The equatorial Pacific warming deepens the Aleutian low, advecting warm air into the North American Arctic. The extratropical North Atlantic and North Pacific SST warming strengthens surface westerly winds over northern Eurasia, intensifying the warming there. Coupled ocean–atmosphere simulations support the constructive intensification of Arctic warming by a concurrent, negative-to-positive phase shift of the Pacific and Atlantic interdecadal modes. Our results aid attributing the historical Arctic warming and thereby constrain the amplified warming projected for this important region. PMID:28559341

Ecosystem dynamics of the Pacific-influenced Northern Bering and Chukchi Seas in the Amerasian Arctic

NASA Astrophysics Data System (ADS)

Grebmeier, Jacqueline M.; Cooper, Lee W.; Feder, Howard M.; Sirenko, Boris I.

2006-10-01

The shallow continental shelves and slope of the Amerasian Arctic are strongly influenced by nutrient-rich Pacific waters advected over the shelves from the northern Bering Sea into the Arctic Ocean. These high-latitude shelf systems are highly productive both as the ice melts and during the open-water period. The duration and extent of seasonal sea ice, seawater temperature and water mass structure are critical controls on water column production, organic carbon cycling and pelagic-benthic coupling. Short food chains and shallow depths are characteristic of high productivity areas in this region, so changes in lower trophic levels can impact higher trophic organisms rapidly, including pelagic- and benthic-feeding marine mammals and seabirds. Subsistence harvesting of many of these animals is locally important for human consumption. The vulnerability of the ecosystem to environmental change is thought to be high, particularly as sea ice extent declines and seawater warms. In this review, we focus on ecosystem dynamics in the northern Bering and Chukchi Seas, with a more limited discussion of the adjoining Pacific-influenced eastern section of the East Siberian Sea and the western section of the Beaufort Sea. Both primary and secondary production are enhanced in specific regions that we discuss here, with the northern Bering and Chukchi Seas sustaining some of the highest water column production and benthic faunal soft-bottom biomass in the world ocean. In addition, these organic carbon-rich Pacific waters are periodically advected into low productivity regions of the nearshore northern Bering, Chukchi and Beaufort Seas off Alaska and sometimes into the East Siberian Sea, all of which have lower productivity on an annual basis. Thus, these near shore areas are intimately tied to nutrients and advected particulate organic carbon from the Pacific influenced Bering Shelf-Anadyr water. Given the short food chains and dependence of many apex predators on sea ice, recent reductions in sea ice in the Pacific-influenced sector of the Arctic have the potential to cause an ecosystem reorganization that may alter this benthic-oriented system to one more dominated by pelagic processes.

Remarkable separability of the circulation response to Arctic sea ice loss and greenhouse gas forcing

NASA Astrophysics Data System (ADS)

McCusker, K. E.; Kushner, P. J.; Fyfe, J. C.; Sigmond, M.; Kharin, V. V.; Bitz, C. M.

2017-12-01

Arctic sea ice loss has an important effect on local climate through increases in ocean to atmosphere heat flux and associated feedbacks, and may influence midlatitude climate by changing large-scale circulation that can enhance or counter changes that are due to greenhouse gases. The extent to which climate change in a warming world can be understood as greenhouse gas-induced changes that are modulated by Arctic sea ice loss depends on how additive the responses to the separate influences are. Here we use a novel sea ice nudging methodology in the Canadian Earth System Model, which has a fully coupled ocean, to isolate the effects of Arctic sea ice loss and doubled atmospheric carbon dioxide (CO2) to determine their additivity and sensitivity to mean state. We find that the separate effects of Arctic sea ice loss and doubled CO2 are remarkably additive and relatively insensitive to mean climate state. This separability is evident in several thermodynamic and dynamic fields throughout most of the year, from hemispheric to synoptic scales. The extent to which the regional response to sea ice loss sometimes agrees with and sometimes cancels the response to CO2 is quantified. In this model, Arctic sea ice loss enhances the CO2-induced surface air temperature changes nearly everywhere and zonal wind changes over the Pacific sector, whereas sea ice loss counters CO2-induced sea level pressure changes nearly everywhere over land and zonal wind changes over the Atlantic sector. This separability of the response to Arctic sea ice loss from the response to CO2 doubling gives credence to the body of work in which Arctic sea ice loss is isolated from the forcing that modified it, and might provide a means to better interpret the diverse array of modeling and observational studies of Arctic change and influence.

Winter snow conditions on Arctic sea ice north of Svalbard during the Norwegian young sea ICE (N-ICE2015) expedition

NASA Astrophysics Data System (ADS)

Merkouriadi, Ioanna; Gallet, Jean-Charles; Graham, Robert M.; Liston, Glen E.; Polashenski, Chris; Rösel, Anja; Gerland, Sebastian

2017-10-01

Snow is a crucial component of the Arctic sea ice system. Its thickness and thermal properties control heat conduction and radiative fluxes across the ocean, ice, and atmosphere interfaces. Hence, observations of the evolution of snow depth, density, thermal conductivity, and stratigraphy are crucial for the development of detailed snow numerical models predicting energy transfer through the snow pack. Snow depth is also a major uncertainty in predicting ice thickness using remote sensing algorithms. Here we examine the winter spatial and temporal evolution of snow physical properties on first-year (FYI) and second-year ice (SYI) in the Atlantic sector of the Arctic Ocean, during the Norwegian young sea ICE (N-ICE2015) expedition (January to March 2015). During N-ICE2015, the snow pack consisted of faceted grains (47%), depth hoar (28%), and wind slab (13%), indicating very different snow stratigraphy compared to what was observed in the Pacific sector of the Arctic Ocean during the SHEBA campaign (1997-1998). Average snow bulk density was 345 kg m-3 and it varied with ice type. Snow depth was 41 ± 19 cm in January and 56 ± 17 cm in February, which is significantly greater than earlier suggestions for this region. The snow water equivalent was 14.5 ± 5.3 cm over first-year ice and 19 ± 5.4 cm over second-year ice.

Influence of ENSO on Gulf Stream cyclogenesis and the North Atlantic storm track

NASA Astrophysics Data System (ADS)

Li, C.; Schemm, S.; Ciasto, L.; Kvamsto, N. G.

2015-12-01

There is emerging evidence that climate in the North Atlantic-European sector is sensitive to vacillations of tropical Pacific sea surface temperatures, in particular, the central Pacific flavour of the El Nino Southern Oscillation (ENSO) and concomitant trends in atmospheric heating. The frequency of central Pacific ENSOs appears to have increased over the last decades and some studies suggest it may continue increasing in the future, but the precise mechanisms by which these events affect the North Atlantic synoptic scale circulation are poorly understood. Here, we show that central Pacific ENSOs influence where midlatitude cyclogenesis occurs over the Gulf Stream, producing more cyclogenesis in the jet exit region rather than in the climatologically preferred jet entrance region. The cyclones forming over the Gulf Stream in central Pacific ENSO seasons tend to veer north, penetrating deeper into the Arctic rather than into continental Europe. The shift in cyclogenesis is linked to changes in the large scale circulation, namely, the upper-level trough formed in the lee of the Rocky Mountains.

Circum-arctic plate accretion - Isolating part of a pacific plate to form the nucleus of the Arctic Basin

USGS Publications Warehouse

Churkin, M.; Trexler, J.H.

1980-01-01

A mosaic of large lithospheric plates rims the Arctic Ocean Basin, and foldbelts between these plates contain numerous allochthonous microplates. A new model for continental drift and microplate accretion proposes that prior to the late Mesozoic the Kula plate extended from the Pacific into the Arctic. By a process of circumpolar drift and microplate accretion, fragments of the Pacific basin, including parts of the Kula plate, were cut off and isolated in the Arctic Ocean, the Yukon-Koyukuk basin in Alaska, and the Bering Sea. ?? 1980.

Selected physical, biological and biogeochemical implications of a rapidly changing Arctic Marginal Ice Zone

NASA Astrophysics Data System (ADS)

Barber, David G.; Hop, Haakon; Mundy, Christopher J.; Else, Brent; Dmitrenko, Igor A.; Tremblay, Jean-Eric; Ehn, Jens K.; Assmy, Philipp; Daase, Malin; Candlish, Lauren M.; Rysgaard, Søren

2015-12-01

The Marginal Ice Zone (MIZ) of the Arctic Ocean is changing rapidly due to a warming Arctic climate with commensurate reductions in sea ice extent and thickness. This Pan-Arctic review summarizes the main changes in the Arctic ocean-sea ice-atmosphere (OSA) interface, with implications for primary- and secondary producers in the ice and the underlying water column. Changes in the Arctic MIZ were interpreted for the period 1979-2010, based on best-fit regressions for each month. Trends of increasingly open water were statistically significant for each month, with quadratic fit for August-November, illustrating particularly strong seasonal feedbacks in sea-ice formation and decay. Geographic interpretations of physical and biological changes were based on comparison of regions with significant changes in sea ice: (1) The Pacific Sector of the Arctic Ocean including the Canada Basin and the Beaufort, Chukchi and East Siberian seas; (2) The Canadian Arctic Archipelago; (3) Baffin Bay and Hudson Bay; and (4) the Barents and Kara seas. Changes in ice conditions in the Barents sea/Kara sea region appear to be primarily forced by ocean heat fluxes during winter, whereas changes in the other sectors appear to be more summer-autumn related and primarily atmospherically forced. Effects of seasonal and regional changes in OSA-system with regard to increased open water were summarized for photosynthetically available radiation, nutrient delivery to the euphotic zone, primary production of ice algae and phytoplankton, ice-associated fauna and zooplankton, and gas exchange of CO2. Changes in the physical factors varied amongst regions, and showed direct effects on organisms linked to sea ice. Zooplankton species appear to be more flexible and likely able to adapt to variability in the onset of primary production. The major changes identified for the ice-associated ecosystem are with regard to production timing and abundance or biomass of ice flora and fauna, which are related to regional changes in sea-ice conditions.

50 CFR Table 2d to Part 679 - Species Codes-Non-FMP Species

Code of Federal Regulations, 2011 CFR

2011-10-01

... description Code Arctic char, anadromous 521 Dolly varden, anadromous 531 Eels or eel-like fish 210 Eel, wolf... Arctic surf 812 Cockle 820 Eastern softshell 842 Pacific geoduck 815 Pacific littleneck 840 Pacific razor...

The Arctic Marine Pulses Model: Linking Contiguous Domains in the Pacific Arctic Region

NASA Astrophysics Data System (ADS)

Moore, S. E.; Stabeno, P. J.

2016-02-01

The Pacific Arctic marine ecosystem extends from the northern Bering Sea, across the Chukchi and into the East Siberian and Beaufort seas. Food webs in this domain are short, a simplicity that belies the biophysical complexity underlying trophic linkages from primary production to humans. Existing biophysical models, such as pelagic-benthic coupling and advective processes, provide frameworks for connecting certain aspects of the marine food web, but do not offer a full accounting of events that occur seasonally across the Pacific Arctic. In the course of the Synthesis of Arctic Research (SOAR) project, a holistic Arctic Marine Pulses (AMP) model was developed that depicts seasonal biophysical `pulses' across a latitudinal gradient, and linking four previously-described contiguous domains, including the: (i) Pacific-Arctic domain = the focal region; (ii) seasonal ice zone domain; (iii) Pacific marginal domain; and (iv) riverine coastal domain. The AMP model provides a spatial-temporal framework to guide research on dynamic ecosystem processes during this period of rapid biophysical changes in the Pacific Arctic. Some of the processes included in the model, such as pelagic-benthic coupling in the Northern Bering and Chukchi seas, and advection and upwelling along the Beaufort shelf, are already the focus of sampling via the Distributed Biological Observatory (DBO) and other research programs. Other aspects such as biological processes associated with the seasonal ice zone and trophic responses to riverine outflow have received less attention. The AMP model could be enhanced by the application of visualization tools to provide a means to watch a season unfold in space and time. The capability to track sea ice dynamics and water masses and to move nutrients, prey and upper-trophic predators in space and time would provide a strong foundation for the development of predictive human-inclusive ecosystem models for the Pacific Arctic.

Record low sea-ice concentration in the central Arctic during summer 2010

NASA Astrophysics Data System (ADS)

Zhao, Jinping; Barber, David; Zhang, Shugang; Yang, Qinghua; Wang, Xiaoyu; Xie, Hongjie

2018-01-01

The Arctic sea-ice extent has shown a declining trend over the past 30 years. Ice coverage reached historic minima in 2007 and again in 2012. This trend has recently been assessed to be unique over at least the last 1450 years. In the summer of 2010, a very low sea-ice concentration (SIC) appeared at high Arctic latitudes—even lower than that of surrounding pack ice at lower latitudes. This striking low ice concentration—referred to here as a record low ice concentration in the central Arctic (CARLIC)—is unique in our analysis period of 2003-15, and has not been previously reported in the literature. The CARLIC was not the result of ice melt, because sea ice was still quite thick based on in-situ ice thickness measurements. Instead, divergent ice drift appears to have been responsible for the CARLIC. A high correlation between SIC and wind stress curl suggests that the sea ice drift during the summer of 2010 responded strongly to the regional wind forcing. The drift trajectories of ice buoys exhibited a transpolar drift in the Atlantic sector and an eastward drift in the Pacific sector, which appeared to benefit the CARLIC in 2010. Under these conditions, more solar energy can penetrate into the open water, increasing melt through increased heat flux to the ocean. We speculate that this divergence of sea ice could occur more often in the coming decades, and impact on hemispheric SIC and feed back to the climate.

Arctic biogeography: The paradox of the marine benthic fauna and flora.

PubMed

Dunton, K

1992-06-01

The marine benthic fauna and flora that inhabit the shallow arctic sublittoral zone comprise a relatively young marine assemblage characterized by species of either Pacific or Atlantic affinity and notably few endemics. The young character of nearshore arctic communities, as well as their biogeographical composition, is largely a product of the Pleistocene glaciation. However, analysis of more recent collections and comparison between the origins of the benthic fauna and flora present some interesting paradoxes to biogeographers. One enigma is the low frequency of algal species with Pacific affinities in the Arctic, especially in the Chukchi, Beaufort and East Siberian Seas of the Eastern Arctic, which receive direct inputs of northward-flowing Pacific waters. In contrast, animal species with Pacific affinities are found throughout the nearshore regions of the Arctic, reaching their highest frequency in the marginal seas between the New Siberian Islands and the Canadian Archipelago. Organization of published and unpublished data, additional field collections, and the use of cladistics and molecular DNA techniques by systematists are a high priority for future research in reconstructing the evolution of the arctic biotic assemblage. Copyright © 1992. Published by Elsevier Ltd.

Using fluorescent dissolved organic matter to trace and distinguish the origin of Arctic surface waters

PubMed Central

Gonçalves-Araujo, Rafael; Granskog, Mats A.; Bracher, Astrid; Azetsu-Scott, Kumiko; Dodd, Paul A.; Stedmon, Colin A.

2016-01-01

Climate change affects the Arctic with regards to permafrost thaw, sea-ice melt, alterations to the freshwater budget and increased export of terrestrial material to the Arctic Ocean. The Fram and Davis Straits represent the major gateways connecting the Arctic and Atlantic. Oceanographic surveys were performed in the Fram and Davis Straits, and on the east Greenland Shelf (EGS), in late summer 2012/2013. Meteoric (fmw), sea-ice melt, Atlantic and Pacific water fractions were determined and the fluorescence properties of dissolved organic matter (FDOM) were characterized. In Fram Strait and EGS, a robust correlation between visible wavelength fluorescence and fmw was apparent, suggesting it as a reliable tracer of polar waters. However, a pattern was observed which linked the organic matter characteristics to the origin of polar waters. At depth in Davis Strait, visible wavelength FDOM was correlated to apparent oxygen utilization (AOU) and traced deep-water DOM turnover. In surface waters FDOM characteristics could distinguish between surface waters from eastern (Atlantic + modified polar waters) and western (Canada-basin polar waters) Arctic sectors. The findings highlight the potential of designing in situ multi-channel DOM fluorometers to trace the freshwater origins and decipher water mass mixing dynamics in the region without laborious samples analyses. PMID:27667721

Future Arctic temperature change resulting from a range of aerosol emissions scenarios

DOE PAGES

Wobus, Cameron; Flanner, Mark; Sarofim, Marcus C.; ...

2016-05-17

The Arctic temperature response to emissions of aerosols – specifically black carbon (BC), organic carbon (OC), and sulfate – depends on both the sector and the region where these emissions originate. Thus, the net Arctic temperature response to global aerosol emissions reductions will depend strongly on the blend of emissions sources being targeted. We use recently published equilibrium Arctic temperature response factors for BC, OC, and sulfate to estimate the range of present-day and future Arctic temperature changes from seven different aerosol emissions scenarios. Globally, Arctic temperature changes calculated from all of these emissions scenarios indicate that present-day emissions frommore » the domestic and transportation sectors generate the majority of present-day Arctic warming from BC. However, in all of these scenarios, this warming is more than offset by cooling resulting from SO 2 emissions from the energy sector. Thus, long-term climate mitigation strategies that are focused on reducing carbon dioxide (CO 2) emissions from the energy sector could generate short-term, aerosol-induced Arctic warming. As a result, a properly phased approach that targets BC-rich emissions from the transportation sector as well as the domestic sectors in key regions – while simultaneously working toward longer-term goals of CO 2 mitigation – could potentially avoid some amount of short-term Arctic warming.« less

U.S. Geological Survey offshore program of resource and geo-environmental studies and topical investigations, Pacific-Arctic region

USGS Publications Warehouse

Scholl, David William

1978-01-01

The Geological Survey 's marine geology investigations in the Pacific-Arctic area are presented in this report in the context of the underlying socio-economic problem of expanding the domestic production of oil and gas and other mineral and hard- and soft-rock resources while maintaining acceptable standards in the marine environment. The primary mission of the Survey 's Pacific-Arctic Branch of Marine Geology is to provide scientifically interpreted information about the (1) resource potential, (2) geo-environmental setting, and (3) overall geologic characteristics of the continental margins (that is, the continental shelf, slope and rise) and adjacent deeper water and shallower coastal areas off California, Oregon, Washington, Alaska and Hawaii and also, where it is of interest to the U.S. Government, more remote deep-sea areas of the Pacific-Arctic realm. (Sinha-OEIS)

Temperature-Dependent Lipid Storage of Juvenile Arctic cod (Boreogadus saida) and Co-Occurring North Pacific Gadids

NASA Astrophysics Data System (ADS)

Copeman, L.; Laurel, B.; Spencer, M. L.; Iseri, P.; Sremba, A. L.

2016-02-01

Climate change impacts on Arctic ecosystems will largely be determined by temperature-dependent bioenergetics of resident and invading forage fish species. In this study, we experimentally measured total lipids and lipid class storage in the liver and muscle of juvenile Arctic gadids (Arctic cod, Boreogadus saida and saffron cod, Eleginus gracilis) and two North Pacific gadids (walleye pollock, Gadus chalcogrammus and Pacific cod, Gadus macrocephalus). Experiments were conducted over a 6-wk period across five temperatures (0, 5, 9, 16 and 20 °C) at the Hatfield Marine Science Center in Newport, OR, USA. Results indicated clear physiological differences among species in terms of temperature-dependent growth and lipid storage. Arctic cod exhibited highest growth and lipid storage (27 mg/g WW) at the coldest temperature (0 °C) compared to the other gadids, with near maximum growth at 5 °C and onset of mortality above 9 °C. In contrast, saffron cod growth rates steadily increased at temperatures beyond 16 °C, but lipid storage was low overall with only slightly higher lipid storage at warm temperatures (10 to 17 mg/g WW). Both walleye pollock and Pacific cod showed a domed response with increased lipid storage and growth at intermediate temperatures (9 - 12°C) and reduced growth and lipid storage at cold and warm maxima. We did not observe a trade-off between growth rate and lipid accumulation in any species. These results suggest that saffron cod can thrive in a warming Arctic but will be energetically inferior as a prey item to the more temperature-sensitive Arctic cod. Alternatively, North Pacific gadids can energetically resemble Arctic cod at warmer temperatures and could theoretically be an important prey item if their range extends northward with continued climate change.

Occurrence of perfluoroalkyl compounds in surface waters from the North Pacific to the Arctic Ocean.

PubMed

Cai, Minghong; Zhao, Zhen; Yin, Zhigao; Ahrens, Lutz; Huang, Peng; Cai, Minggang; Yang, Haizhen; He, Jianfeng; Sturm, Renate; Ebinghaus, Ralf; Xie, Zhiyong

2012-01-17

Perfluoroalkyl compounds (PFCs) were determined in 22 surface water samples (39-76°N) and three sea ice core and snow samples (77-87°N) collected from North Pacific to the Arctic Ocean during the fourth Chinese Arctic Expedition in 2010. Geographically, the average concentration of ∑PFC in surface water samples were 560 ± 170 pg L(-1) for the Northwest Pacific Ocean, 500 ± 170 pg L(-1) for the Arctic Ocean, and 340 ± 130 pg L(-1) for the Bering Sea, respectively. The perfluoroalkyl carboxylates (PFCAs) were the dominant PFC class in the water samples, however, the spatial pattern of PFCs varied. The C(5), C(7) and C(8) PFCAs (i.e., perfluoropentanoate (PFPA), perfluoroheptanoate (PFHpA), and perfluorooctanoate (PFOA)) were the dominant PFCs in the Northwest Pacific Ocean while in the Bering Sea the PFPA dominated. The changing in the pattern and concentrations in Pacific Ocean indicate that the PFCs in surface water were influenced by sources from the East-Asian (such as Japan and China) and North American coast, and dilution effect during their transport to the Arctic. The presence of PFCs in the snow and ice core samples indicates an atmospheric deposition of PFCs in the Arctic. The elevated PFC concentration in the Arctic Ocean shows that the ice melting had an impact on the PFC levels and distribution. In addition, the C(4) and C(5) PFCAs (i.e., perfluorobutanoate (PFBA), PFPA) became the dominant PFCs in the Arctic Ocean indicating that PFBA is a marker for sea ice melting as the source of exposure.

Arctic-North Pacific Coupled Impacts on the Late Autumn Cold in North America

NASA Technical Reports Server (NTRS)

Sung, Mi-Kyung; Kim, Baek-Min; Baik, Eun-Hyuk; Lim, Young-Kwon; Kim, Seong-Joong

2016-01-01

The Pacific Decadal Oscillation (PDO) is known to bring an anomalously cold (warm) period to southeastern (northwestern) North America during the cold season of its positive phase through a Rossby wave linkage. This study provides evidence that the remote connection between the North Pacific and the downstream temperature over central North America is strengthened by the warm arctic conditions over the Chukchi and East Siberian Sea, especially in the late autumn season. The modulation effect of the Arctic manifests itself as an altered Rossby wave response to a transient vorticity forcing that results from an equatorward storm track shift, which is induced collaboratively by the PDO and the warm Arctic. This observational finding is supported by two independent modeling experiments: 1) an idealized coupled GCM experiment being nudged toward the warm arctic surface condition and 2) a simple stationary wave model (SWM) experiment forced by transient eddy forcing.

A Paleo Perspective on Arctic and Mid-latitude Linkages from a Southeast Alaska Ice Core

NASA Astrophysics Data System (ADS)

Porter, S. E.; Mosley-Thompson, E.; Thompson, L. G.; Bolzan, J. F.

2017-12-01

Recent extreme weather events in the Northern Hemisphere have been linked to anomalously amplified jet stream patterns, North Pacific marine heatwaves, retreating Arctic sea ice extent, and/or the combination thereof. The role of the Arctic in influencing mid-latitude weather and extreme events is a burgeoning topic of climate research that is limited primarily to the recent decades in which Arctic amplification and shrinking Arctic sea ice extent are occurring. Paleo-proxy data afford an opportunity to place the changing Arctic and its far-reaching climatic consequences in the longer context of Earth's climate history and allow identification of time periods with conditions analogous to the present. Ice core-derived annual net accumulation from the Bona-Churchill (BC) ice core, retrieved in 2002 from the Wrangell-St. Elias mountain range in southeast Alaska, is used to explore the historical characteristics of the regional North Pacific climate and the further afield teleconnections. Variability of accumulation on BC is driven primarily by shifts in the position of the Aleutian Low which influences the available moisture sources for the drill site. The accumulation record is also related to sea surface temperatures in the Gulf of Alaska, defined here by the North Pacific Mode and somewhat colloquially as the North Pacific "blob". Thus due to its connection with the Aleutian Low and North Pacific sea surface temperatures, this uniquely situated ice core record indirectly captures the phasing of troughs and ridges in the polar jet stream over North America, and thereby facilitates examination of the atmospheric wave structure prior to the instrumental record. The relationships among the ice core accumulation record and various North Pacific climate features are presented along with evidence identifying specific time periods possibly characterized by persistently amplified wave patterns.

On the Influence of North Pacific Sea Surface Temperature on the Arctic Winter Climate

NASA Technical Reports Server (NTRS)

Hurwitz, Margaret M.; Newman, P. A.; Garfinkel, C. I.

2012-01-01

Differences between two ensembles of Goddard Earth Observing System Chemistry-Climate Model simulations isolate the impact of North Pacific sea surface temperatures (SSTs) on the Arctic winter climate. One ensemble of extended winter season forecasts is forced by unusually high SSTs in the North Pacific, while in the second ensemble SSTs in the North Pacific are unusually low. High Low differences are consistent with a weakened Western Pacific atmospheric teleconnection pattern, and in particular, a weakening of the Aleutian low. This relative change in tropospheric circulation inhibits planetary wave propagation into the stratosphere, in turn reducing polar stratospheric temperature in mid- and late winter. The number of winters with sudden stratospheric warmings is approximately tripled in the Low ensemble as compared with the High ensemble. Enhanced North Pacific SSTs, and thus a more stable and persistent Arctic vortex, lead to a relative decrease in lower stratospheric ozone in late winter, affecting the April clear-sky UV index at Northern Hemisphere mid-latitudes.

Influence of climate variability on near-surface ozone depletion events in the Arctic spring

NASA Astrophysics Data System (ADS)

Koo, Ja-Ho; Wang, Yuhang; Jiang, Tianyu; Deng, Yi; Oltmans, Samuel J.; Solberg, Sverre

2014-04-01

Near-surface ozone depletion events (ODEs) generally occur in the Arctic spring, and the frequency shows large interannual variations. We use surface ozone measurements at Barrow, Alert, and Zeppelinfjellet to analyze if their variations are due to climate variability. In years with frequent ODEs at Barrow and Alert, the western Pacific (WP) teleconnection pattern is usually in its negative phase, during which the Pacific jet is strengthened but the storm track originated over the western Pacific is weakened. Both factors tend to reduce the transport of ozone-rich air mass from midlatitudes to the Arctic, creating a favorable environment for the ODEs. The correlation of ODE frequencies at Zeppelinfjellet with WP indices is higher in the 2000s, reflecting stronger influence of the WP pattern in recent decade to cover ODEs in broader Arctic regions. We find that the WP pattern can be used to diagnose ODE changes and subsequent environmental impacts in the Arctic spring.

77 FR 66564 - North Pacific Fishery Management Council; Essential Fish Habitat Amendments

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-06

...-XA500 North Pacific Fishery Management Council; Essential Fish Habitat Amendments AGENCY: National... Scallop Fishery off Alaska (Scallop FMP); and Amendment 1 to the FMP for Fish Resources of the Arctic Management Area (Arctic FMP). These amendments update the existing essential fish habitat (EFH) provisions in...

Radiocesium in the western subarctic area of the North Pacific Ocean, Bering Sea, and Arctic Ocean in 2013 and 2014.

PubMed

Kumamoto, Yuichiro; Aoyama, Michio; Hamajima, Yasunori; Nishino, Shigeto; Murata, Akihiko; Kikuchi, Takashi

2017-08-01

We measured radiocesium ( 134 Cs and 137 Cs) in seawater from the western subarctic area of the North Pacific Ocean, Bering Sea, and Arctic Ocean in 2013 and 2014. Fukushima-derived 134 Cs in surface seawater was observed in the western subarctic area and Bering Sea but not in the Arctic Ocean. Vertical profile of 134 Cs in the Canada Basin of the Arctic Ocean implies that Fukushima-derived 134 Cs intruded into the basin from the Bering Sea through subsurface (150m depth) in 2014. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distribution of Arctic and Pacific copepods and their habitat in the northern Bering and Chukchi seas

NASA Astrophysics Data System (ADS)

Sasaki, Hiroko; Matsuno, Kohei; Fujiwara, Amane; Onuka, Misaki; Yamaguchi, Atsushi; Ueno, Hiromichi; Watanuki, Yutaka; Kikuchi, Takashi

2016-08-01

The advection of warm Pacific water and the reduction in sea ice in the western Arctic Ocean may influence the abundance and distribution of copepods, a key component of food webs. To quantify the factors affecting the abundance of copepods in the northern Bering and Chukchi seas, we constructed habitat models explaining the spatial patterns of large and small Arctic and Pacific copepods separately. Copepods were sampled using NORPAC (North Pacific Standard) nets. The structures of water masses indexed by principle component analysis scores, satellite-derived timing of sea ice retreat, bottom depth and chlorophyll a concentration were integrated into generalized additive models as explanatory variables. The adequate models for all copepods exhibited clear continuous relationships between the abundance of copepods and the indexed water masses. Large Arctic copepods were abundant at stations where the bottom layer was saline; however they were scarce at stations where warm fresh water formed the upper layer. Small Arctic copepods were abundant at stations where the upper layer was warm and saline and the bottom layer was cold and highly saline. In contrast, Pacific copepods were abundant at stations where the Pacific-origin water mass was predominant (i.e. a warm, saline upper layer and saline and a highly saline bottom layer). All copepod groups showed a positive relationship with early sea ice retreat. Early sea ice retreat has been reported to initiate spring blooms in open water, allowing copepods to utilize more food while maintaining their high activity in warm water without sea ice and cold water. This finding indicates that early sea ice retreat has positive effects on the abundance of all copepod groups in the northern Bering and Chukchi seas, suggesting a change from a pelagic-benthic-type ecosystem to a pelagic-pelagic type.

Summer Sea ice in the Pacific Arctic sector from the CHINARE-2010 cruise

NASA Astrophysics Data System (ADS)

Ackley, S. F.; Xie, H.; Lei, R.; Huang, W.; Chinare 2010 Arctic Sea Ice Group

2010-12-01

The Fourth Chinese National Arctic Research Expedition (CHINARE) from July 1 to Sep. 23, 2010, the last Chinese campaign in Arctic Ocean contributing to the fourth International Polar Year (IPY), conducted comprehensive scientific studies on ocean-ice-atmosphere interaction and the marine ecosystem’s response to climatic change in Arctic. This paper presents an overview on sea ice (ice concentration, floe size, melt pond coverage, sea ice and snow thickness) of the Pacific Arctic sector, in particular between 150°W to 180°W to 86°N, based on: (1) underway visual observations of sea ice at half-hourly and automatic cameras recording (both side looking from the icebreaker R.V. Xuelong) every 10 to 15 seconds; (2) a downward-looking video mounted on the left side of the vessel at a height of 7 m above waterline recording overturning of ice floes; (3) on-site measurements of snow and ice thickness using drilling and electromagnetic instrument EM31 (9.8 kHz) at eight short-term (~3 hours each) and one 12-day ice stations; (4) six flights of aerial photogrammetry from helicopter, and (5) Satellite data (AMSE-E ice concentration and ENVISAT ASAR) and NIC ice charts) that extended the observations/measurements along beyond the ship track and airborne flights. In the northward leg, the largest ice concentration zone was in the area starting from ~75°N (July 29), with ice concentration of 60-90% (mean ~80%), ice thickness of 1.5-2m, melt ponds of 10-50% of ice, ridged ice of 10-30% of ice, and floe size of 100’s meters to kms. The 12-day ice station (from Aug 7-19), started at 86.92°N/178.88°W and moved a total of 175.7km, was on an ice floe over 100 km2 in size and ~2 m in mean thickness. There were two heavy and several slight snowfall events in the period (July 29 to Aug 19). Snow thickness varies from 5cm to 15 cm, and melted about 5cm during the 12-day ice camp. In the southward leg, the largest sea ice concentration zone was in the area between 87°N to 80°N (from August 21 to August 24). In this area, the ice concentration varied from 70-100%, melt pond varied from 20-50% of ice, ridged ice varied from 10-30% of ice, and floe size was dominated by 10’s km to several km’s in one or two dimensions. The overall ice thickness decreased southward from 1.8-2m to 0.6-1m. The ice type of the area is multiyear ice dominated, with small portion of first year ice. In the area from ~85°N to 83.5°N, we see dirty ice (brownish, rich hills and valleys, mostly multiyear ice), varying from 10-20% of ice. Similar dirty ice was only seen from 72°N-75°N in the northward leg (July 24-29), then not seen until the northern region. The ice situation in this cruise will be compared with that from the CHINARE-2008 cruise, in a similar area and season, so change of the two years for this sector of Arctic Ocean during the middle-later summer can be deduced.

Projected status of the Pacific walrus (Odobenus rosmarus divergens) in the twenty-first century

Treesearch

Chadwick V. Jay; Bruce G. Marcot; David C. Douglas

2011-01-01

Extensive and rapid losses of sea ice in the Arctic have raised conservation concerns for the Pacific walrus (Odobenus rosmarus divergens), a large pinniped inhabiting arctic and subarctic continental shelf waters of the Chukchi and Bering seas. We developed a Bayesian network model to integrate potential effects of changing environmental...

Anthropogenic 129I in the North Pacific, Bering and Chukchi Seas, and Arctic Ocean in 2012-2013

NASA Astrophysics Data System (ADS)

Nagai, H.; Hasegawa, A.; Yamagata, T.; Kumamoto, Y.; Nishino, S.; Matsuzaki, H.

2015-10-01

Most of anthropogenic 129I in marine environment are due to discharge from the nuclear fuel reprocessing facilities at Sellafield (U.K.) and La Hague (France) for past few decades. The discharge raised 129I concentration in seawaters in the North Atlantic and Arctic Oceans to more than 109 atoms L-1, which is two orders of magnitude higher than that in other region. Recently, in March 2011, a large quantity of 129I was released into the western North Pacific due to the Fukushima Daiichi Nuclear Power Plant (F1NPP) accident. To evaluate the influence of these events, we have measured 129I concentration in seawaters in the northern North Pacific Ocean, Bering and Chukchi Seas, and Arctic Ocean in 2012-2013. The 129I concentrations were 1.0-1.8 × 107 atoms L-1 in the surface waters in the vicinity of 47°N 150°E-130°W North Pacific Ocean, Bering Sea, and Chukchi Sea (<74°N), which are equal to or lower than the 129I concentration level in surface water in the North Pacific Ocean before the F1NPP accident. The vertical profiles in the North Pacific were almost same as that observed in the western North Pacific before the F1NPP accident. The 129I distribution in seawater in the North Pacific to the Chukchi Sea revealed no significant increase of 129I concentration caused by the F1NPP accident. The 129I concentrations were 13-14 × 107 atoms L-1 in surface waters and 80 × 107 atoms L-1 at depths of 300 and 800 m in the Arctic Ocean.

Earth: Physico-mathematical Meaning of "primary" and "secondary" Oceans Conception

NASA Astrophysics Data System (ADS)

Kochemasov, G.

Geologists term the Pacific ocean "primary" and Atlantic and Indian oceans "sec- ondary" meaning that the first is larger, deeper, older (?) and plays more fundamental role in the Earth's tectonics. The wave planetology as hierarchically higher than geol- ogy (Earth is only one of planets and of many celestial bodies), states that all celestial bodies are dichotomic ( "Pacific" as a tectonic feature is found in any celestial body) and sectoral (i.g., the Arctic-Antarctic symptom is also in any body) (Theorems 1, 2 [1]). The tectonic dichotomy and sectoring are related to the first and second harmon- ica (wave1 and wave2) of warping standing waves appearing in any body just because they move in non-circular (elliptic, parabolic) orbits and hence inertia forces tend to distort original shapes. This disfiguring of a rotating body is not just a superficial fea- ture, it involves fundamental changes in the entire vertical section above and below surface rises and falls (Theorem 4 [1]). Here acts the law of angular momentum equi- libration. Thus, under the Pacific basin hollow -the deepest hollow produced by wave1 - mantle is denser than under the Atlantic and Indian oceanic basins - basins produced by wave2. We know it because squeezed out of mantle tholeiites in the mid-oceanic ridges are Fe-richer in Pacific than in other oceans. The "primary" ocean is thus a fundamental or "wave1" or 2pR-structure. The "secondary" oceans are "wave2" or pR-structures. pR-structures represented by continents, secondary oceans and basins and the "superswell" (Darwin rise) in the Pacific, i.e. by most important terrestrial lithospheric tectonic blocks, are distributed on the Earth's surface not randomly. As must be expected of the standing wave interference picture, the pR-structure pattern shows regular grouping around certain centres. There are 6 centres - vertices of an oc- tahedron occurring at equator (1, 2), tropics (3, 4) and polar circles (5, 6). They are: 1. New Guinea, 2. Equatorial Atlantic, 3. Easter Isl., 4. the Pamirs-Hindukush, 5. Bering Strait, 6. Bouvet Isl. There is expected antipodality between 1-2, 3-4, 5-6. The vertices of the structural octahedron combine around them sectors by a similar algorithm: there always converge two opposite differently uplifted sectors separated by two differently 1 subsided sectors. I.g., around the Pamirs-Hindukush there are two uplifted sectors: African (++) Asian (+), and two separating them subsided ones: Eurasian (-) Indo- ceanic (- -). The cosmically oriented structural octahedron and other regularities show that the wave induced structurization is a real predominant factor in planetology. Ref. [1] Kochemasov G.G.(1999) Geophys.Res.Abstr., v.1, 3, 700. 2

Whales, Dolphins, and Porpoises of the Eastern North Pacific and Adjacent Arctic Waters: A Guide to Their Identification.

ERIC Educational Resources Information Center

Leatherwood, Stephen; And Others

This field guide is designed to permit observers to identify the cetaceans (whales, dolphins, and porpoises) they see in the waters of the eastern North Pacific, including the Gulf of California, Hawaii, and the western Arctic of North America. The animals described are grouped not by scientific relationships but by similarities in appearance in…

Is it ‘boom times’ for baleen whales in the Pacific Arctic region?

PubMed Central

2016-01-01

The marine ecosystem in the Pacific Arctic region has experienced dramatic transformation, most obvious by the loss of sea ice volume (75%), late-summer areal extent (50%) and change in phenology (four to six weeks longer open-water period). This alteration has resulted in an opening of habitat for subarctic species of baleen whales, many of which are recovering in number from severe depletions from commercial whaling in the nineteenth and twentieth centuries. Specifically, humpback, fin and minke whales (Megaptera novaeangliae, Balaenoptera physalus and Balaenoptera acutorostrata) are now regularly reported during summer and autumn in the southern Chukchi Sea. These predators of zooplankton and forage fishes join the seasonally resident grey whale (Eschrichtius robustus) and the arctic-endemic bowhead whale (Balaena mysticetus) in the expanding open-ocean habitat of the Pacific Arctic. Questions arising include: (i) what changes in whale-prey production and delivery mechanisms have accompanied the loss of sea ice, and (ii) how are these five baleen whale species partitioning the expanding ice-free habitat? While there has been no programme of research specifically focused on these questions, an examination of seasonal occurrence, foraging plasticity and (for bowhead whales) body condition suggests that the current state of Pacific Arctic marine ecosystem may be ‘boom times’ for baleen whales. These favourable conditions may be moderated, however, by future shifts in ecosystem structure and/or negative impacts to cetaceans related to increased commercial activities in the region. PMID:27601724

Is it 'boom times' for baleen whales in the Pacific Arctic region?

PubMed

Moore, Sue E

2016-09-01

The marine ecosystem in the Pacific Arctic region has experienced dramatic transformation, most obvious by the loss of sea ice volume (75%), late-summer areal extent (50%) and change in phenology (four to six weeks longer open-water period). This alteration has resulted in an opening of habitat for subarctic species of baleen whales, many of which are recovering in number from severe depletions from commercial whaling in the nineteenth and twentieth centuries. Specifically, humpback, fin and minke whales (Megaptera novaeangliae, Balaenoptera physalus and Balaenoptera acutorostrata) are now regularly reported during summer and autumn in the southern Chukchi Sea. These predators of zooplankton and forage fishes join the seasonally resident grey whale (Eschrichtius robustus) and the arctic-endemic bowhead whale (Balaena mysticetus) in the expanding open-ocean habitat of the Pacific Arctic. Questions arising include: (i) what changes in whale-prey production and delivery mechanisms have accompanied the loss of sea ice, and (ii) how are these five baleen whale species partitioning the expanding ice-free habitat? While there has been no programme of research specifically focused on these questions, an examination of seasonal occurrence, foraging plasticity and (for bowhead whales) body condition suggests that the current state of Pacific Arctic marine ecosystem may be 'boom times' for baleen whales. These favourable conditions may be moderated, however, by future shifts in ecosystem structure and/or negative impacts to cetaceans related to increased commercial activities in the region. © 2016 The Author(s).

The Deglacial to Holocene Paleoceanography of Bering Strait: Results From the SWERUS-C3 Program

NASA Astrophysics Data System (ADS)

Jakobsson, M.; Anderson, L. G.; Backman, J.; Barrientos, N.; Björk, G. M.; Coxall, H.; Cronin, T. M.; De Boer, A. M.; Gemery, L.; Jerram, K.; Johansson, C.; Kirchner, N.; Mayer, L. A.; Mörth, C. M.; Nilsson, J.; Noormets, R. R. N. N.; O'Regan, M.; Pearce, C.; Semiletov, I. P.; Stranne, C.

2017-12-01

The climate-carbon-cryosphere (C3) interactions in the East Siberian Arctic Ocean and related ocean, river and land areas of the Arctic have been the focus for the SWERUS-C3 Program (Swedish - Russian - US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions). This multi-investigator, multi-disciplinary program was carried out on a two-leg 90-day long expedition in 2014 with Swedish icebreaker Oden. One component of the expedition consisted of geophysical mapping and coring of Herald Canyon, located on the Chukchi Sea shelf north of the Bering Strait in the western Arctic Ocean. Herald Canyon is strategically placed to capture the history of the Pacific-Arctic Ocean connection and related changes in Arctic Ocean paleoceanography. Here we present a summary of key results from analyses of the marine geophysical mapping data and cores collected from Herald Canyon on the shelf and slope that proved to be particularly well suited for paleoceanographic reconstruction. For example, we provide a new age constraint of 11 cal ka BP on sediments from the uppermost slope for the initial flooding of the Bering Land Bridge and reestablishment of the Pacific-Arctic Ocean connection following the last glaciation. This age corresponds to meltwater pulse 1b (MWP1b) known as a post-Younger Dryas warming in many sea level and paleoclimate records. In addition, high late Holocene sedimentation rates that range between about 100 and 300 cm kyr-1, in Herald Canyon permitted paleoceanographic reconstructions of ocean circulation and sea ice cover at centennial scales throughout the late Holocene. Evidence suggests varying influence from inflowing Pacific water into the western Arctic Ocean including some evidence for quasi-cyclic variability in several paleoceanographic parameters, e.g. micropaleontological assemblages, isotope geochemistry and sediment physical properties.

Trends in aerosol optical depth in the Russian Arctic and their links with synoptic climatology.

PubMed

Shahgedanova, Maria; Lamakin, Mikhail

2005-04-01

Temporal and spatial variability of aerosol optical depth (AOD) are examined using observations of direct solar radiation in the Eurasian Arctic for 1940-1990. AOD is estimated using empirical methods for 14 stations located between 66.2 degrees N and 80.6 degrees N, from the Kara Sea to the Chukchi Sea. While AOD exhibits a well-known springtime maximum and summertime minimum at all stations, atmospheric turbidity is higher in spring in the western (Kara-Laptev) part of the Eurasian Arctic. Between June and August, the eastern (East Siberian-Chukchi) sector experiences higher transparency than the western part. A statistically significant positive trend in AOD was observed in the Kara-Laptev sector between the late 1950s and the early 1980s predominantly in spring when pollution-derived aerosol dominates the Arctic atmosphere but not in the eastern sector. Although all stations are remote, those with positive trends are located closer to the anthropogenic sources of air pollution. By contrast, a widespread decline in AOD was observed between 1982 and 1990 in the eastern Arctic in spring but was limited to two sites in the western Arctic. These results suggest that the post-1982 decline in anthropogenic emissions in Europe and the former Soviet Union has had a limited effect on aerosol load in the Arctic. The post-1982 negative trends in AOD in summer, when marine aerosol is present in the atmosphere, were more common in the west. The relationships between AOD and atmospheric circulation are examined using a synoptic climatology approach. In spring, AOD depends primarily on the strength and direction of air flow. Thus strong westerly and northerly flows result in low AOD values in the East Siberian-Chukchi sector. By contrast, strong southerly flow associated with the passage of depressions results in high AOD in the Kara-Laptev sector and trajectory analysis points to the contribution of industrial regions of the sub-Arctic. In summer, low pressure gradient or anticyclonic conditions result in high atmospheric turbidity. The frequency of this weather type has declined significantly since the early 1980s in the Kara-Laptev sector, which partly explains the decline in summer AOD values.

Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

NASA Astrophysics Data System (ADS)

Sasaki, H.; Matsuno, K.; Fujiwara, A.; Onuka, M.; Yamaguchi, A.; Ueno, H.; Watanuki, Y.; Kikuchi, T.

2015-11-01

The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

Late Paleozoic to Cenozoic reconstruction of the Arctic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, D.G.

1985-04-01

The plate tectonic evolution of the Arctic is reassessed in the context of the known histories of the North Atlantic and North Pacific Oceans, and of the tectono-stratigraphic development of the lands around the Arctic Ocean. Computer map-drawing facilities were used to provide geometrical constraints on the reconstructions, which are presented to in the form of eight palinispatic maps. Stratigraphic similarities among presently dispersed continental areas identify fragments of a former Barents plate. Collision of this plate with the Euramerican plate was the cause of the Late Devonian Ellesmerian orogeny. In later Paleozoic time, the Siberian continent also joined Pangeamore » by collision with the combined Barents and Euramerican plates along the Ural-Taymyr suture. The Mesozoic-Cenozoic history of the Arctic is concerned with the fragmentation and dispersal of the former Barents plate, as well as the accretion of new continental fragments from the Pacific.« less

77 FR 47356 - North Pacific Fishery Management Council; Essential Fish Habitat Amendments

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

...-XA500 North Pacific Fishery Management Council; Essential Fish Habitat Amendments AGENCY: National... Pacific Fishery Management Council submitted the following essential fish habitat (EFH) amendments to NMFS... Scallop Fishery off Alaska; and Amendment 1 to the FMP for Fish Resources of the Arctic Management Area...

The Arctic: Glacial Refugium or Area of Secondary Contact? Inference from the Population Genetic Structure of the Thick-Billed Murre (Uria lomvia), with Implications for Management.

PubMed

Tigano, Anna; Damus, Martin; Birt, Tim P; Morris-Pocock, Jamie A; Artukhin, Yuri B; Friesen, Vicki L

2015-01-01

Quaternary glaciations affected the distribution of many species. Here, we investigate whether the Arctic represented a glacial refugium during the Last Glacial Maximum or an area of secondary contact following the ice retreat, by analyzing the genetic population structure of the thick-billed murre (Uria lomvia), a seabird that breeds throughout the North Atlantic, North Pacific and Arctic Oceans. The thick-billed murre is a species of socio-economic importance and faces numerous threats including hunting, oil pollution, gill netting, and climate change. We compared variation in the mitochondrial DNA (mtDNA) control region (n = 424), supplemented by 4 microsatellite loci (n = 445), among thick-billed murres sampled throughout their range. MtDNA data indicated that colonies comprise 4 genetically differentiated groups (Φst = 0.11-0.81): 1) Atlantic Ocean plus New Siberian Islands region, 2) Cape Parry, 3) Chukchi Sea, and 4) Pacific Ocean. Microsatellite variation differed between Atlantic and Pacific populations. Otherwise, little substructure was found within either ocean. Atlantic and Pacific populations appear to have been genetically isolated since the last interglacial period and should be considered separate evolutionary significant units for management. The Chukchi Sea and Cape Parry appear to represent areas of secondary contact, rather than arctic refugial populations. © The American Genetic Association 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Quantifying Source Sector and Region Contributions of BC and Dust Deposition on the Arctic Snow and the Resulting Albedo Reduction

NASA Astrophysics Data System (ADS)

Sobhani, N.; Gregory, C.; Kulkarni, S.

2017-12-01

Long-range transport of atmospheric particulate matter (PM) from mid-latitude sources to the Arctic is the main contributor to the Arctic PM loadings and deposition. Light absorbing particles such as Black Carbon (BC) and dust are considered of great climatic importance and are the main absorbers of sunlight in the atmosphere. Wet and dry deposition of light absorbing particles (LAPs) on snow and ice cause reduction of snow and ice albedo. LAPs have significant radiative forcing and effect on snow albedo causing snow and ice to warm and melt more quickly. There are large uncertainties in estimating radiative forcing of LAPs. In this study, the potential impacts of LAPs from different emission source regions and sectors on snow albedo in the Arctic are studied. A modeling framework including Weather Research and Forecasting Model (WRF) and the University of Iowa's Sulfur Transport and dEpostion model (STEM) is used to simulate the seasonality and transport of LAPs from different geographical sources and sectors (i.e. transportation, residential, industry, biomass burning and power) to the Arctic. The main geographical source contributor to the Arctic BC annual deposition flux is China. However, there is a distinct seasonal variation for the contributions of geographical source emissions to BC deposition. During the spring, when the deposition flux is highest, the contribution of biomass burning attributes for up to 40% of total deposition at Alert and Barrow. However, during the winter, the anthropogenic sectors contribute up to 95% of total BC deposition. The simulated snow BC mixing ratios are evaluated using the observed BC snow concentration values from previous studies including Doherty et al., 2010. The simulations show the BC deposition causes 0.6% snow albedo decrease during spring 2008 over the Arctic.

Toward Evaluating the Predictability of Arctic-related Climate Variations: Initial Results from ArCS Project Theme 5

NASA Astrophysics Data System (ADS)

Hasumi, H.

2016-12-01

We present initial results from the theme 5 of the project ArCS, which is a national flagship project for Arctic research in Japan. The goal of theme 5 is to evaluate the predictability of Arctic-related climate variations, wherein we aim to: (1) establish the scientific basis of climate predictability; and (2) develop a method for predicting/projecting medium- and long-term climate variations. Variability in the Arctic environment remotely influences middle and low latitudes. Since some of the processes specific to the Arctic environment function as a long memory of the state of the climate, understanding of the process of remote connections would lead to higher-precision and longer-term prediction of global climate variations. Conventional climate models have large uncertainty in the Arctic region. By making Arctic processes in climate models more sophisticated, we aim to clarify the role of multi-sphere interaction in the Arctic environment. In this regard, our newly developed high resolution ice-ocean model has revealed the relationship between the oceanic heat transport into the Arctic Ocean and the synoptic scale atmospheric variability. We also aim to reveal the mechanism of remote connections by conducting climate simulations and analyzing various types of climate datasets. Our atmospheric model experiments under possible future situations of Arctic sea ice cover indicate that reduction of sea ice qualitatively alters the basic mechanism of remote connection. Also, our analyses of climate data have identified the cause of recent more frequent heat waves at Eurasian mid-to-high latitudes and clarified the dynamical process which forms the West Pacific pattern, a dominant mode of the atmospheric anomalous circulation in the West Pacific region which also exhibits a significant signal in the Arctic stratosphere.

Connections between the tropical Pacific Ocean, Arctic sea ice, and anomalous northeastern Pacific ridging

NASA Astrophysics Data System (ADS)

Swain, D. L.; Singh, D.; Horton, D. E.; Mankin, J. S.; Ballard, T.; Thomas, L. N.; Diffenbaugh, N. S.

2016-12-01

The ongoing and severe drought in California is linked to the multi-year persistence of anomalously strong ridging along the west coast of North America, which has deflected the Pacific storm track north of its climatological mean position. Recent work has shown that that highly amplified and strongly meridional atmospheric flow patterns in this region similar to the "Ridiculously Resilient Ridge" have become more common in recent decades. Previous investigations have suggested multiple possible contributors to this conspicuous atmospheric anomaly—including remote teleconnections to unusual tropical Pacific Ocean warmth and/or reduced Arctic sea ice, internal (natural) atmospheric variability, and anthropogenic forcing due to greenhouse gas emissions. Here, we explore observed relationships between mid-tropospheric atmospheric structure in this region and five hypothesized surface forcings: sea ice extent in the (1) Barents/Kara and (2) Beaufort/Chukchi regions, and sea surface temperatures in the (3) extratropical northeastern Pacific Ocean, (4) western tropical Pacific Ocean, and (5) eastern tropical Pacific Ocean. Using a predictive model based upon these observed relationships, we also investigate whether the failure of the powerful 2015-2016 El Niño event to bring above-average precipitation to California could have been predicted based upon these teleconnections.

Fate of polycyclic aromatic hydrocarbons from the North Pacific to the Arctic: Field measurements and fugacity model simulation.

PubMed

Ke, Hongwei; Chen, Mian; Liu, Mengyang; Chen, Meng; Duan, Mengshan; Huang, Peng; Hong, Jiajun; Lin, Yan; Cheng, Shayen; Wang, Xuran; Huang, Mengxue; Cai, Minggang

2017-10-01

Polycyclic aromatic hydrocarbons (PAHs) have accumulated ubiquitously inArctic environments, where re-volatilization of certain organic pollutants as a result of climate change has been observed. To investigate the fate of semivolatile organic compounds in the Arctic, dissolved PAHs in the surface seawaters from the temperate Pacific Ocean to the Arctic Ocean, as well as a water column in the Arctic Ocean, were collected during the 4th Chinese National Arctic Research Expedition in summer 2010. The total concentrations of seven dissolved PAHs in surface water ranged from 1.0 to 5.1 ng L -1 , decreasing with increasing latitude. The vertical profile of PAHs in the Arctic Ocean was generally characteristic of surface enrichment and depth depletion, which emphasized the role of vertical water stratification and particle settling processes. A level III fugacity model was developed in the Bering Sea under steady state assumption. Model results quantitatively simulated the transfer processes and fate of PAHs in the air and water compartments, and highlighted a summer air-to-sea flux of PAHs in the Bering Sea, which meant that the ocean served as a sink for PAHs, at least in summer. Acenaphthylene and acenaphthene reached equilibrium in air-water diffusive exchange, and any perturbation, such as a rise in temperature, might lead to disequilibrium and remobilize these compounds from their Arctic reservoirs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

NASA Astrophysics Data System (ADS)

Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert; Babb, David G.; Toudal Pedersen, Leif; Rysgaard, Søren; Kristoffersen, Yngve; Barber, David G.

2017-12-01

The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature-salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean-glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

Processes of multibathyal aragonite undersaturation in the Arctic Ocean

USGS Publications Warehouse

Wynn, J.G.; Robbins, L.L.; Anderson, L.G.

2016-01-01

During 3 years of study (2010–2012), the western Arctic Ocean was found to have unique aragonite saturation profiles with up to three distinct aragonite undersaturation zones. This complexity is produced as inflow of Atlantic-derived and Pacific-derived water masses mix with Arctic-derived waters, which are further modified by physiochemical and biological processes. The shallowest aragonite undersaturation zone, from the surface to ∼30 m depth is characterized by relatively low alkalinity and other dissolved ions. Besides local influence of biological processes on aragonite undersaturation of shallow coastal waters, the nature of this zone is consistent with dilution by sea-ice melt and invasion of anthropogenic CO2 from the atmosphere. A second undersaturated zone at ∼90–220 m depth (salinity ∼31.8–35.4) occurs within the Arctic Halocline and is characterized by elevated pCO2 and nutrients. The nature of this horizon is consistent with remineralization of organic matter on shallow continental shelves bordering the Canada Basin and the input of the nutrients and CO2 entrained by currents from the Pacific Inlet. Finally, the deepest aragonite undersaturation zone is at greater than 2000 m depth and is controlled by similar processes as deep aragonite saturation horizons in the Atlantic and Pacific Oceans. The comparatively shallow depth of this deepest aragonite saturation horizon in the Arctic is maintained by relatively low temperatures, and stable chemical composition. Understanding the mechanisms controlling the distribution of these aragonite undersaturation zones, and the time scales over which they operate will be crucial to refine predictive models.

Adaptive strategies and life history characteristics in a warming climate: salmon in the Arctic?

USGS Publications Warehouse

Nielsen, Jennifer L.; Ruggerone, Gregory T.; Zimmerman, Christian E.

2013-01-01

In the warming Arctic, aquatic habitats are in flux and salmon are exploring their options. Adult Pacific salmon, including sockeye (Oncorhynchus nerka), coho (O. kisutch), Chinook (O. tshawytscha), pink (O. gorbuscha) and chum (O. keta) have been captured throughout the Arctic. Pink and chum salmon are the most common species found in the Arctic today. These species are less dependent on freshwater habitats as juveniles and grow quickly in marine habitats. Putative spawning populations are rare in the North American Arctic and limited to pink salmon in drainages north of Point Hope, Alaska, chum salmon spawning rivers draining to the northwestern Beaufort Sea, and small populations of chum and pink salmon in Canada’s Mackenzie River. Pacific salmon have colonized several large river basins draining to the Kara, Laptev and East Siberian seas in the Russian Arctic. These populations probably developed from hatchery supplementation efforts in the 1960’s. Hundreds of populations of Arctic Atlantic salmon (Salmo salar) are found in Russia, Norway and Finland. Atlantic salmon have extended their range eastward as far as the Kara Sea in central Russian. A small native population of Atlantic salmon is found in Canada’s Ungava Bay. The northern tip of Quebec seems to be an Atlantic salmon migration barrier for other North American stocks. Compatibility between life history requirements and ecological conditions are prerequisite for salmon colonizing Arctic habitats. Broad-scale predictive models of climate change in the Arctic give little information about feedback processes contributing to local conditions, especially in freshwater systems. This paper reviews the recent history of salmon in the Arctic and explores various patterns of climate change that may influence range expansions and future sustainability of salmon in Arctic habitats. A summary of the research needs that will allow informed expectation of further Arctic colonization by salmon is given.

The phenology of Arctic Ocean surface warming.

PubMed

Steele, Michael; Dickinson, Suzanne

2016-09-01

In this work, we explore the seasonal relationships (i.e., the phenology) between sea ice retreat, sea surface temperature (SST), and atmospheric heat fluxes in the Pacific Sector of the Arctic Ocean, using satellite and reanalysis data. We find that where ice retreats early in most years, maximum summertime SSTs are usually warmer, relative to areas with later retreat. For any particular year, we find that anomalously early ice retreat generally leads to anomalously warm SSTs. However, this relationship is weak in the Chukchi Sea, where ocean advection plays a large role. It is also weak where retreat in a particular year happens earlier than usual, but still relatively late in the season, primarily because atmospheric heat fluxes are weak at that time. This result helps to explain the very different ocean warming responses found in two recent years with extreme ice retreat, 2007 and 2012. We also find that the timing of ice retreat impacts the date of maximum SST, owing to a change in the ocean surface buoyancy and momentum forcing that occurs in early August that we term the Late Summer Transition (LST). After the LST, enhanced mixing of the upper ocean leads to cooling of the ocean surface even while atmospheric heat fluxes are still weakly downward. Our results indicate that in the near-term, earlier ice retreat is likely to cause enhanced ocean surface warming in much of the Arctic Ocean, although not where ice retreat still occurs late in the season.

Composition of the summer photosynthetic pico and nanoplankton communities in the Beaufort Sea assessed by T-RFLP and sequences of the 18S rRNA gene from flow cytometry sorted samples.

PubMed

Balzano, Sergio; Marie, Dominique; Gourvil, Priscillia; Vaulot, Daniel

2012-08-01

The composition of photosynthetic pico and nanoeukaryotes was investigated in the North East Pacific and the Arctic Ocean with special emphasis on the Beaufort Sea during the MALINA cruise in summer 2009. Photosynthetic populations were sorted using flow cytometry based on their size and pigment fluorescence. Diversity of the sorted photosynthetic eukaryotes was determined using terminal-restriction fragment length polymorphism analysis and cloning/sequencing of the 18S ribosomal RNA gene. Picoplankton was dominated by Mamiellophyceae, a class of small green algae previously included in the prasinophytes: in the North East Pacific, the contribution of an Arctic Micromonas ecotype increased steadily northward becoming the only taxon occurring at most stations throughout the Beaufort Sea. In contrast, nanoplankton was more diverse: North Pacific stations were dominated by Pseudo-nitzschia sp. whereas those in the Beaufort Sea were dominated by two distinct Chaetoceros species as well as by Chrysophyceae, Pelagophyceae and Chrysochromulina spp.. This study confirms the importance of Arctic Micromonas within picoplankton throughout the Beaufort Sea and demonstrates that the photosynthetic picoeukaryote community in the Arctic is much less diverse than at lower latitudes. Moreover, in contrast to what occurs in warmer waters, most of the key pico- and nanoplankton species found in the Beaufort Sea could be successfully established in culture.

[Corynosoma hannae Zdzitowiecki, 1984--a parasite of sea leopard from the Pacific sector of Antarctic].

PubMed

Striukov, A A; Iurakhno, M V

2007-01-01

Specimens of the acanthocephalan Corynosoma hannae Zdzitowiecki, 1984 from the Pacific (Balleni islands) and Atlantic (South Shetland) sectors of Antarctic are compared with those from the Pacific sector of Subantarctic (Auckland and Campbell islands). Probably New Zealand sea lion Phocarctos hookeri (Gray, 1844) is the secondary definitive host for Corynosoma hannae. Description and figures of the specimens examined are provided.

The state of climate change adaptation in the Arctic

NASA Astrophysics Data System (ADS)

Ford, James D.; McDowell, Graham; Jones, Julie

2014-10-01

The Arctic climate is rapidly changing, with wide ranging impacts on natural and social systems. A variety of adaptation policies, programs and practices have been adopted to this end, yet our understanding of if, how, and where adaptation is occurring is limited. In response, this paper develops a systematic approach to characterize the current state of adaptation in the Arctic. Using reported adaptations in the English language peer reviewed literature as our data source, we document 157 discrete adaptation initiatives between 2003 and 2013. Results indicate large variations in adaptation by region and sector, dominated by reporting from North America, particularly with regards to subsistence harvesting by Inuit communities. Few adaptations were documented in the European and Russian Arctic, or have a focus on the business and economy, or infrastructure sectors. Adaptations are being motivated primarily by the combination of climatic and non-climatic factors, have a strong emphasis on reducing current vulnerability involving incremental changes to existing risk management processes, and are primarily initiated and led at the individual/community level. There is limited evidence of trans-boundary adaptations or initiatives considering potential cross-scale/sector impacts.

Spatial heterogeneity in zooplankton summer distribution in the eastern Chukchi Sea in 2012-2013 as a result of large-scale interactions of water masses

NASA Astrophysics Data System (ADS)

Pinchuk, Alexei I.; Eisner, Lisa B.

2017-01-01

Interest in the Arctic shelf ecosystems has increased in recent years as the climate has rapidly warmed and sea ice declined. These changing conditions prompted the broad-scale multidisciplinary Arctic Ecosystem integrated survey (Arctic Eis) aimed at systematic, comparative analyses of interannual variability of the shelf ecosystem. In this study, we compared zooplankton composition and geographical distribution in relation to water properties on the eastern Chukchi and northern Bering Sea shelves during the summers of 2012 and 2013. In 2012, waters of Pacific origin prevailed over the study area carrying expatriate oceanic species (e.g. copepods Neocalanus spp., Eucalanus bungii) from the Bering Sea outer shelf well onto the northeastern Chukchi shelf. In contrast, in 2013, zooplankton of Pacific origin was mainly distributed over the southern Chukchi shelf, suggesting a change of advection pathways into the Arctic. These changes also manifested in the emergence of large lipid-rich Arctic zooplankton (e.g. Calanus hyperboreus) on the northeastern Chukchi shelf in 2013. The predominant copepod Calanus glacialis was composed of two distinct populations originating from the Bering Sea and from the Arctic, with the Arctic population expanding over a broader range in 2013. The observed interannual variability in zooplankton distribution on the Chukchi Sea shelf may be explained by previously described systematic oceanographic patterns derived from long-term observations. Variability in oceanic circulation and related zooplankton distributions (e.g. changes in southwestward advection of C. hyperboreus) may impact keystone predators such as Arctic Cod (Boreogadus saida) that feed on energy-rich zooplankton.

Organophosphate Ester Flame Retardants and Plasticizers in Ocean Sediments from the North Pacific to the Arctic Ocean.

PubMed

Ma, Yuxin; Xie, Zhiyong; Lohmann, Rainer; Mi, Wenying; Gao, Guoping

2017-04-04

The presence of organophosphate ester (OPE) flame retardants and plasticizers in surface sediment from the North Pacific to Arctic Ocean was observed for the first time during the fourth National Arctic Research Expedition of China in the summer of 2010. The samples were analyzed for three halogenated OPEs [tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP), and tris(dichloroisopropyl) phosphate], three alkylated OPEs [triisobutyl phosphate (TiBP), tri-n-butyl phosphate, and tripentyl phosphate], and triphenyl phosphate. Σ 7 OPEs (total concentration of the observed OPEs) was in the range of 159-4658 pg/g of dry weight. Halogenated OPEs were generally more abundant than the nonhalogenated OPEs; TCEP and TiBP dominated the overall concentrations. Except for that of the Bering Sea, Σ 7 OPEs values increased with increasing latitudes from Bering Strait to the Central Arctic Ocean, while the contributions of halogenated OPEs (typically TCEP and TCPP) to the total OPE profile also increased from the Bering Strait to the Central Arctic Ocean, indicating they are more likely to be transported to the remote Arctic. The median budget of 52 (range of 17-292) tons for Σ 7 OPEs in sediment from the Central Arctic Ocean represents only a very small amount of their total production volume, yet the amount of OPEs in Arctic Ocean sediment was significantly larger than the sum of polybrominated diphenyl ethers (PBDEs) in the sediment, indicating they are equally prone to long-range transport away from source regions. Given the increasing level of production and usage of OPEs as substitutes of PBDEs, OPEs will continue to accumulate in the remote Arctic.

78 FR 53731 - North Pacific Fishery Management Council; Notice of Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-30

... meetings. SUMMARY: The North Pacific Fishery Management Council (Council) Ecosystem Committee will meet in... agenda will be as follows: Development of Ecosystem-based management (EMB) vision statement; Operationalizing EBM in Council projects, including the Aleutian Islands Fishery Ecosystem Plan, the Arctic Fishery...

Towards understanding the role of the Bering Strait in the Plio-Pleistocene climate change

NASA Astrophysics Data System (ADS)

Okazaki, Y.; Onodera, J.; Teraishi, A.; Suto, I.

2011-12-01

The Bering Strait is the gateway between Pacific and Arctic, plays an important role in global freshwater cycle and eventually influences on climate change. The glacial Pacific Ocean had well-ventilated and nutrient-depleted glacial North Pacific Intermediate Water (GNPIW) above ~2000 m. GNPIW is a thicker and more deeply penetrating water mass than today's North Pacific Intermediate Water (NPIW). The source of GNPIW was likely in the Bering Sea based on neodymium isotope evidence. During Heinrich Event 1 in the early deglacial period, deep water extending to a depth of ~2500 m formed in the North Pacific. Modeling simulations suggest that a closed Bering Strait is essentially required for salinity built-up in the North Pacific to form the deep water. First opening of the Bering Strait was suggested to be in the latest Miocene and have repeated opening and closure by eustatic sea-level change associated with climate changes. However, our knowledge on the history about the opening/closure is limited due to lack of appropriate samples. During the IODP Expedition 323, Pliocene to Pleistocene marine sediment was continuously recovered from the Bering Sea. At the northern Bering continental slope sites (U1343 and U1344), the period with high abundance of diatom species Neodenticula seminae is terminated around 0.8-0.9 Ma, which appears to coincide with the Mid-Pleistocene Transition (MPT). While Neodenticula seminae is an endemic and predominant diatom in the modern subarctic Pacific and the Aleutian basin of the Bering Sea, the occurrence of this species is reported from the sediments between 0.84 and 1.25 Ma in the northern North Atlantic. This suggests a significantly intensified Arctic Throughflow and adaptive environment for N. seminae production from the Bering Strait to the Greenland Sea during the MPT. The observations of hydrography and the modern re-appearance of this taxon since 1999 in the Labrador Sea due to the melting of the Arctic Sea ice also suggests the specific requirements by this species: low salinity and high dissolved silicon concentrations. During the glacial cycles of the last 800 kyr, a limited input of Pacific water into the Arctic Ocean or disconnection was suggested by decreased abundances of N. seminae. Furthermore, repeated abundance peaks of radiolarian species Cycladophora davisiana, indicating cold and well ventilated intermediate water, suggest enhancement of intermediate to deep water formation in the Bering Sea during glacial periods, when the Bering Strait was closed. This research used samples and data provided by the IODP. We acknowledge the IODP Expedition 323 Shipboard Scientists.

Implications of ocean acidification in the Pacific Arctic: Experimental responses of three Arctic bivalves to decreased pH and food availability

NASA Astrophysics Data System (ADS)

Goethel, Christina L.; Grebmeier, Jacqueline M.; Cooper, Lee W.; Miller, Thomas J.

2017-10-01

Recent sea ice retreat and seawater warming in the Pacific Arctic are physical changes that are impacting arctic biological communities. Recently, ocean acidification from increases in anthropogenic CO2 has been identified as an additional stressor, particularly to calcifying organisms like bivalves. These bivalves are common prey items for benthivorous predators such as Pacific walruses (Odobenus rosmarus divergens), bearded seals (Erignathus barbatus), and diving seaducks, such as Spectacled Eiders (Somateria fischeri). We investigated the effects of decreased pH and food availability on growth (% change in length and wet weight and allometric growth characterizations) and oxygen consumption (mg/L/hour) of three common Arctic bivalves, Macoma calcarea, Astarte montagui, and Astarte borealis. Two sets of experiments were run for seven and eleven weeks, exposing the bivalves to control (8.05 ± 0.02 and 8.19 ± 0.003, respectively) and acidified (7.76 ± 0.01 and 7.86 ± 0.01, respectively) pH treatments. Length, weight, and oxygen consumption were not significantly different among the varying treatments after the seven-week exposure and only one significant effect of decreased pH and one significant effect of decreased food availability were observed after the end of the eleven-week exposure. Specifically, shells of A. borealis displayed a decrease in length in response to decreased pH and M. calcarea showed a decrease in length in response to limited food. The negative effects of pH observed in the experiments on growth and oxygen consumption were small, suggesting that at least two of these species are generally resilient to decreasing pH.

Inter-Relationship Between Subtropical Pacific Sea Surface Temperature, Arctic Sea Ice Concentration, and the North Atlantic Oscillation in Recent Summers and Winters

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon; Cullather, Richard I.; Nowicki, Sophie M.; Kim, Kyu-Myong

2017-01-01

The inter-relationship between subtropical western-central Pacific sea surface temperatures (STWCPSST), sea ice concentration in the Beaufort Sea (SICBS), and the North Atlantic Oscillation (NAO) are investigated for the last 37 summers and winters (1980-2016). Lag-correlation of the STWCPSST×(-1) in spring with the NAO phase and SICBS in summer increases over the last two decades, reaching r = 0.4-0.5 with significance at 5 percent, while winter has strong correlations in approximately 1985-2005. Observational analysis and the atmospheric general circulation model experiments both suggest that STWCPSST warming acts to increase the Arctic geopotential height and temperature in the following season. This atmospheric response extends to Greenland, providing favorable conditions for developing the negative phase of the NAO. SIC and surface albedo tend to decrease over the Beaufort Sea in summer, linked to the positive surface net shortwave flux. Energy balance considering radiative and turbulent fluxes reveal that available energy that can heat surface is larger over the Arctic and Greenland and smaller over the south of Greenland, in response to the STWCPSST warming in spring. XXXX Arctic & Atlantic: Positive upper-level height/T anomaly over the Arctic and Greenland, and a negative anomaly over the central-eastern Atlantic, resembling the (-) phase of the NAO. Pacific: The negative height/T anomaly over the mid-latitudes, along with the positive anomaly over the STWCP, where 1degC warming above climatology is prescribed. Discussion: It is likely that the Arctic gets warm and the NAO is in the negative phase in response to the STWCP warming. But, there are other factors (e.g., internal variability) that contribute to determination of the NAO phase: not always the negative phase of the NAO in the event of STWCP warming (e.g.: recent winters and near neutral NAO in 2017 summer).

Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments.

PubMed

Aksenov, Yevgeny; Karcher, Michael; Proshutinsky, Andrey; Gerdes, Rüdiger; de Cuevas, Beverly; Golubeva, Elena; Kauker, Frank; Nguyen, An T; Platov, Gennady A; Wadley, Martin; Watanabe, Eiji; Coward, Andrew C; Nurser, A J George

2016-01-01

Pacific Water (PW) enters the Arctic Ocean through Bering Strait and brings in heat, fresh water, and nutrients from the northern Bering Sea. The circulation of PW in the central Arctic Ocean is only partially understood due to the lack of observations. In this paper, pathways of PW are investigated using simulations with six state-of-the art regional and global Ocean General Circulation Models (OGCMs). In the simulations, PW is tracked by a passive tracer, released in Bering Strait. Simulated PW spreads from the Bering Strait region in three major branches. One of them starts in the Barrow Canyon, bringing PW along the continental slope of Alaska into the Canadian Straits and then into Baffin Bay. The second begins in the vicinity of the Herald Canyon and transports PW along the continental slope of the East Siberian Sea into the Transpolar Drift, and then through Fram Strait and the Greenland Sea. The third branch begins near the Herald Shoal and the central Chukchi shelf and brings PW into the Beaufort Gyre. In the models, the wind, acting via Ekman pumping, drives the seasonal and interannual variability of PW in the Canadian Basin of the Arctic Ocean. The wind affects the simulated PW pathways by changing the vertical shear of the relative vorticity of the ocean flow in the Canada Basin.

Recent Trends in the Arctic Navigable Ice Season and Links to Atmospheric Circulation

NASA Astrophysics Data System (ADS)

Maslanik, J.; Drobot, S.

2002-12-01

One of the potential effects of Arctic climate warming is an increase in the navigable ice season, perhaps resulting in development of the Arctic as a major shipping route. The distance from western North American ports to Europe through the Northwest Passage (NWP) or the Northern Sea Route (NSR) is typically 20 to 60 percent shorter than travel through the Panama Canal, while travel between Europe and the Far East may be reduced by as much as three weeks compared to transport through the Suez Canal. An increase in the navigable ice season would also improve commercial opportunities within the Arctic region, such as mineral and oil exploration and tourism, which could potentially expand the economic base of Arctic residents and companies, but which would also have negative environmental impacts. Utilizing daily passive-microwave derived sea ice concentrations, trends and variability in the Arctic navigable ice season are examined from 1979 through 2001. Trend analyses suggest large increases in the length of the navigable ice season in the Kara and Barents seas, the Sea of Okhotsk, and the Beaufort Sea, with decreases in the length of the navigable ice season in the Bering Sea. Interannual variations in the navigable ice season largely are governed by fluctuations in low-frequency atmospheric circulation, although the specific annular modes affecting the length of the navigable ice season vary by region. In the Beaufort and East Siberian seas, variations in the North Atlantic Oscillation/Arctic Oscillation control the navigable ice season, while variations in the East Pacific anomaly play an important role in controlling the navigable ice season in the Kara and Barents seas. In Hudson Bay, the Canadian Arctic Archipelago, and Baffin Bay, interannual variations in the navigable ice season are strongly related to the Pacific Decadal Oscillation.

Extensive under-ice turbulence microstructure measurements in the central Arctic Ocean in 2015

NASA Astrophysics Data System (ADS)

Rabe, Benjamin; Janout, Markus; Graupner, Rainer; Hoelemann, Jens; Hampe, Hendrik; Hoppmann, Mario; Horn, Myriel; Juhls, Bennet; Korhonen, Meri; Nikolopoulos, Anna; Pisarev, Sergey; Randelhoff, Achim; Savy, John-Philippe; Villacieros, Nicolas

2016-04-01

The Arctic Ocean is a strongly stratified low-energy environment, where tides are weak and the upper ocean is protected by an ice cover during much of the year. Interior mixing processes are dominated by double diffusion. The upper Arctic Ocean features a cold surface mixed layer, which, separated by a sharp halocline, protects the sea ice from the warmer underlying Atlantic- and Pacific-derived water masses. These water masses carry nutrients that are important for the Arctic ecosystem. Hence vertical fluxes of heat, salt, and nutrients are crucial components in understanding the Arctic ecosystem. Yet, direct flux measurements are difficult to obtain and hence sparse. In 2015, two multidisciplinary R/V Polarstern expeditions to the Arctic Ocean resulted in a series of under-ice turbulence microstructure measurements. These cover different locations across the Eurasian and Makarov Basins, during the melt season in spring and early summer as well as during freeze-up in late summer. Sampling was carried out from ice floes with repeated profiles resulting in 4-24 hour-long time series. 2015 featured anomalously warm atmospheric conditions during summer followed by unusually low temperatures in September. Our measurements show elevated dissipation rates at the base of the mixed layer throughout all stations, with significantly higher levels above the Eurasian continental slope when compared with the Arctic Basin. Additional peaks were found between the mixed layer and the halocline, in particular at stations where Pacific Summer water was present. This contribution provides first flux estimates and presents first conclusions regarding the impact of atmospheric and sea ice conditions on vertical mixing in 2015.

Melting barriers to faunal exchange across ocean basins.

PubMed

McKeon, C Seabird; Weber, Michele X; Alter, S Elizabeth; Seavy, Nathaniel E; Crandall, Eric D; Barshis, Daniel J; Fechter-Leggett, Ethan D; Oleson, Kirsten L L

2016-02-01

Accelerated loss of sea ice in the Arctic is opening routes connecting the Atlantic and Pacific Oceans for longer periods each year. These changes may increase the ease and frequency with which marine birds and mammals move between the Pacific and Atlantic Ocean basins. Indeed, recent observations of birds and mammals suggest these movements have intensified in recent decades. Reconnection of the Pacific and Atlantic Ocean basins will present both challenges to marine ecosystem conservation and an unprecedented opportunity to examine the ecological and evolutionary consequences of interoceanic faunal exchange in real time. To understand these changes and implement effective conservation of marine ecosystems, we need to further develop modeling efforts to predict the rate of dispersal and consequences of faunal exchange. These predictions can be tested by closely monitoring wildlife dispersal through the Arctic Ocean and using modern methods to explore the ecological and evolutionary consequences of these movements. © 2015 John Wiley & Sons Ltd.

Arctic warming will promote Atlantic-Pacific fish interchange

NASA Astrophysics Data System (ADS)

Wisz, M. S.; Broennimann, O.; Grønkjær, P.; Møller, P. R.; Olsen, S. M.; Swingedouw, D.; Hedeholm, R. B.; Nielsen, E. E.; Guisan, A.; Pellissier, L.

2015-03-01

Throughout much of the Quaternary Period, inhospitable environmental conditions above the Arctic Circle have been a formidable barrier separating most marine organisms in the North Atlantic from those in the North Pacific. Rapid warming has begun to lift this barrier, potentially facilitating the interchange of marine biota between the two seas. Here, we forecast the potential northward progression of 515 fish species following climate change, and report the rate of potential species interchange between the Atlantic and the Pacific via the Northwest Passage and the Northeast Passage. For this, we projected niche-based models under climate change scenarios and simulated the spread of species through the passages when climatic conditions became suitable. Results reveal a complex range of responses during this century, and accelerated interchange after 2050. By 2100 up to 41 species could enter the Pacific and 44 species could enter the Atlantic, via one or both passages. Consistent with historical and recent biodiversity interchanges, this exchange of fish species may trigger changes for biodiversity and food webs in the North Atlantic and North Pacific, with ecological and economic consequences to ecosystems that at present contribute 39% to global marine fish landings.

Atmospheric teleconnections between the Arctic and the Baltic Sea regions

NASA Astrophysics Data System (ADS)

Jakobson, L.; Jakobson, E.

2017-12-01

The observed enhanced warming of the Arctic, referred to as the AA, is expected to be related to further changes that impact mid-latitudes and the rest of the world. Our aim is to clarify how the climatic parameters in the Baltic Sea and Arctic regions are associated. Knowledge of such connections helps to define regions in the Arctic that could be with higher extent associated with the Baltic Sea region climate change. We used monthly mean reanalysis data from NCEP-CFSR and ERA-Interim. The strongest teleconnections between the same parameter (temperature, SLP, specific humidity, wind speed) at the Baltic Sea region and the Arctic are found in winter, but they are clearly affected by the Arctic Oscillation (AO) index. After removal of the AO index variability, correlations in winter were everywhere below ±0.5, while in other seasons there remained regions with strong (|R|>0.5, p<0.002) correlations. Strong correlations are also present between different climate variables at the Baltic Sea region and different regions of the Arctic. Temperature from 1000 to 500 hPa level at the Baltic Sea region have a strong negative correlation with the Greenland sector (the region between 20 - 80W and 55 - 80N) during all seasons except summer. The positive temperature anomaly of mild winter at the Greenland sector shifts towards east during the next seasons, reaching to Scandinavia/Baltic Sea region in summer. The Greenland sector is the region which gives the most significant correlations with the climatic parameters (temperature, wind speed, specific humidity, SLP) of the Baltic Sea region. These relationships can be explained by the AO index variability only in winter. In other seasons there has to be other influencing factors. The results of this study are valuable for selecting regions in the Arctic that have statistically the largest effect on climate in the Baltic Sea region.

Amplified North Atlantic warming in the late Pliocene by changes in Arctic gateways

DOE PAGES

Otto-Bliesner, Bette L.; Jahn, Alexandra; Feng, Ran; ...

2016-12-26

Under previous reconstructions of late Pliocene boundary conditions, climate models have failed to reproduce the warm sea surface temperatures reconstructed in the North Atlantic. Using a reconstruction of mid-Piacenzian paleogeography that has the Bering Strait and Canadian Arctic Archipelago Straits closed, however, improves the simulation of the proxy-indicated warm sea surface temperatures in the North Atlantic in the Community Climate System Model. We find that the closure of these small Arctic gateways strengthens the Atlantic Meridional Overturning Circulation, by inhibiting freshwater transport from the Pacific to the Arctic Ocean and from the Arctic Ocean to the Labrador Sea, leading tomore » warmer sea surface temperatures in the North Atlantic. In conclusion, this indicates that the state of the Arctic gateways may influence the sensitivity of the North Atlantic climate in complex ways, and better understanding of the state of these Arctic gateways for past time periods is needed.« less

Energy Content of Arctic Forage Fish

NASA Astrophysics Data System (ADS)

Vollenweider, J.; Heintz, R.; Callahan, M.; Robertson, A.; Barton, M. B.; Sousa, L.; Mueter, F. J.; Mosher, S.; Moran, J.; Logerwell, E.; Boswell, K. M.; Sformo, T.; Farley, E.

2016-02-01

Global changes in climate conditions are most extreme in high latitudes and have the potential to restructure Arctic marine fish assemblages. Of concern is the ability for fish to adapt to changing habitats, the potential for range expansion from lower latitudes, and resultant introduction of competitors and/or predators. Bioenergetic models are useful tools to understand potential cascading trophic effects, and fish energy density is a key parameter in these models. We present energy density (kJ/g dry mass) values for 28 Arctic fish species collected in the Chukchi and Beaufort Seas between 2005 and 2014. Pacific herring (Clupea pallasii) was the most energy-rich species (25.0 kJ/g), followed by two species of primary importance to subsistence people, Arctic cisco (Coregonus autumnalis) and Bering cisco (Coregonus laurettae) (24.9 kJ/g and 23.5 kJ/g, respectively). The abundant and ecologically important Arctic cod (Boreogadus saida) was the most energy-rich gadid, averaging 22.7 kJ/g and having 6% more energy than walleye pollock (Theragra chalcogramma) (21.5 kJ/g) and 11% more energy than saffron cod (Eleginus gracilis) (20.5 kJ/g). In general, pelagic species such as juvenile Pacific salmon (Oncorhynchus sp) had the highest energy content, whereas benthic species such as sculpin (Cottidae), flatfish (Pleuronectidae), eelblennies (Stichaeidae) and eelpouts (Zoarcidae) were amongst the lowest. The high energy content of Arctic cod and their ubiquitous distribution in the water column makes them valuable prey for both demersal and pelagic predators.

Trans-Alaska Crustal Transect and continental evolution involving subduction underplating and synchronous foreland thrusting

USGS Publications Warehouse

Fuis, G.S.; Moore, Thomas E.; Plafker, G.; Brocher, T.M.; Fisher, M.A.; Mooney, W.D.; Nokleberg, W.J.; Page, R.A.; Beaudoin, B.C.; Christensen, N.I.; Levander, A.R.; Lutter, W.J.; Saltus, R.W.; Ruppert, N.A.

2008-01-01

We investigate the crustal structure and tectonic evolution of the North American continent in Alaska, where the continent has grown through magmatism, accretion, and tectonic underplating. In the 1980s and early 1990s, we conducted a geological and geophysical investigation, known as the Trans-Alaska Crustal Transect (TACT), along a 1350-km-long corridor from the Aleutian Trench to the Arctic coast. The most distinctive crustal structures and the deepest Moho along the transect are located near the Pacific and Arctic margins. Near the Pacific margin, we infer a stack of tectonically underplated oceanic layers interpreted as remnants of the extinct Kula (or Resurrection) plate. Continental Moho just north of this underplated stack is more than 55 km deep. Near the Arctic margin, the Brooks Range is underlain by large-scale duplex structures that overlie a tectonic wedge of North Slope crust and mantle. There, the Moho has been depressed to nearly 50 km depth. In contrast, the Moho of central Alaska is on average 32 km deep. In the Paleogene, tectonic underplating of Kula (or Resurrection) plate fragments overlapped in time with duplexing in the Brooks Range. Possible tectonic models linking these two regions include flat-slab subduction and an orogenic-float model. In the Neogene, the tectonics of the accreting Yakutat terrane have differed across a newly interpreted tear in the subducting Pacific oceanic lithosphere. East of the tear, Pacific oceanic lithosphere subducts steeply and alone beneath the Wrangell volcanoes, because the overlying Yakutat terrane has been left behind as underplated rocks beneath the rising St. Elias Range, in the coastal region. West of the tear, the Yakutat terrane and Pacific oceanic lithosphere subduct together at a gentle angle, and this thickened package inhibits volcanism. ?? 2008 The Geological Society of America.

Risk of predation and weather events affect nest site selection by sympatric Pacific (Gavia pacifica) and Yellow-billed (Gavia adamsii) loons in Arctic habitats

USGS Publications Warehouse

Haynes, Trevor B.; Schmutz, Joel A.; Lindberg, Mark S.; Rosenberger, Amanda E.

2014-01-01

Pacific (Gavia pacifica) and Yellow-billed (G. adamsii) loons nest sympatrically in Arctic regions. These related species likely face similar constraints and requirements for nesting success; therefore, use of similar habitats and direct competition for nesting habitat is likely. Both of these loon species must select a breeding lake that provides suitable habitat for nesting and raising chicks; however, characteristics of nest site selection by either species on interior Arctic lakes remains poorly understood. Here, logistic regression was used to compare structural and habitat characteristics of all loon nest locations with random points from lakes on the interior Arctic Coastal Plain, Alaska. Results suggest that both loon species select nest sites to avoid predation and exposure to waves and shifting ice. Loon nest sites were more likely to be on islands and peninsulas (odds ratio = 16.13, 95% CI = 4.64–56.16) than mainland shoreline, which may help loons avoid terrestrial predators. Further, nest sites had a higher degree of visibility (mean degrees of visibility to 100 and 200 m) of approaching predators than random points (odds ratio = 2.57, 95% CI = 1.22–5.39). Nests were sheltered from exposure, having lower odds of being exposed to prevailing winds (odds ratio = 0.34, 95% CI = 0.13–0.92) and lower odds of having high fetch values (odds ratio = 0.46, 95% CI = 0.22–0.96). Differences between Pacific and Yellow-billed loon nesting sites were subtle, suggesting that both species have similar general nest site requirements. However, Yellow-billed Loons nested at slightly higher elevations and were more likely to nest on peninsulas than Pacific Loons. Pacific Loons constructed built up nests from mud and vegetation, potentially in response to limited access to suitable shoreline due to other territorial loons. Results suggest that land managers wishing to protect habitats for these species should focus on lakes with islands as well as shorelines sheltered from exposure to prevailing wind and ice patterns.

Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments

PubMed Central

Karcher, Michael; Proshutinsky, Andrey; Gerdes, Rüdiger; de Cuevas, Beverly; Golubeva, Elena; Kauker, Frank; Nguyen, An T.; Platov, Gennady A.; Wadley, Martin; Watanabe, Eiji; Coward, Andrew C.; Nurser, A. J. George

2016-01-01

Abstract Pacific Water (PW) enters the Arctic Ocean through Bering Strait and brings in heat, fresh water, and nutrients from the northern Bering Sea. The circulation of PW in the central Arctic Ocean is only partially understood due to the lack of observations. In this paper, pathways of PW are investigated using simulations with six state‐of‐the art regional and global Ocean General Circulation Models (OGCMs). In the simulations, PW is tracked by a passive tracer, released in Bering Strait. Simulated PW spreads from the Bering Strait region in three major branches. One of them starts in the Barrow Canyon, bringing PW along the continental slope of Alaska into the Canadian Straits and then into Baffin Bay. The second begins in the vicinity of the Herald Canyon and transports PW along the continental slope of the East Siberian Sea into the Transpolar Drift, and then through Fram Strait and the Greenland Sea. The third branch begins near the Herald Shoal and the central Chukchi shelf and brings PW into the Beaufort Gyre. In the models, the wind, acting via Ekman pumping, drives the seasonal and interannual variability of PW in the Canadian Basin of the Arctic Ocean. The wind affects the simulated PW pathways by changing the vertical shear of the relative vorticity of the ocean flow in the Canada Basin. PMID:27818853

It's in Their Bones: 2000 Years of Pacific Walrus Adaptability and Resilience

NASA Astrophysics Data System (ADS)

Misarti, N.; Horstmann, L.; Clark, C. T.; Charapata, P.; Olson, L.; Fulton, T. L.; Jensen, A. M.

2016-02-01

One of the many species affected by climate change in the Arctic, and receiving attention from the general public, is the Pacific walrus (Odobenus rosmarus divergens). Walruses are of critical importance to subsistence consumers in Alaska (and other Arctic regions) both for practical, financial reasons as well as cultural ones. Despite the quality data from in-depth studies of Pacific walruses over the last 40-50 years, it is difficult to implement proposed co-management and conservation plans based on data from such a relatively short time span; much less to project the impact of further changes to the Arctic ecosystem on both walruses and humans subsisting on them. We are presenting the first data from our project, integrating several disciplines including archaeology, ethnology, biology, and ecology utilizing proxy data, such as DNA, stable isotope (SI), steroid hormones, and trace element analysis as well as ascertain long-term trends of walrus feeding ecology, foraging location, and stock genetics over the last 2000 years. Each set of proxy data acts as a building block to better understand walruses, and how they adapt to change in the Arctic ecosystem. Our preliminary data show that steroid hormone levels change during some decades, including most recently, compared with prehistoric levels and might be associated with walrus population size. SI has revealed several shifts in feeding habits; the last 5 years are significantly different from the historic time periods as well as the prehistoric time frame. Both SI and hormone data are corroborated by traditional ecological knowledge.

Variability of the extent of the Hadley circulation in the southern hemisphere: a regional perspective

NASA Astrophysics Data System (ADS)

Nguyen, H.; Hendon, H. H.; Lim, E.-P.; Boschat, G.; Maloney, E.; Timbal, B.

2018-01-01

In order to understand the regional impacts of variations in the extent of the Hadley circulation in the Southern Hemisphere, regional Hadley circulations are defined in three sectors centered on the main tropical heat sources over Africa, Asia-Pacific (Maritime Continent) and the Americas. These regional circulations are defined by computing a streamfunction from the divergent component of the meridional wind. A major finding from this study is that year-to-year variability in the extent of the hemispheric Hadley circulation in the Southern Hemisphere is primarily governed by variations of the extent of the Hadley circulation in the Asia-Pacific sector, especially during austral spring and summer when there is little co-variability with the African sector, and the American sector exhibits an out of phase behavior. An expanded Hadley circulation in the Southern Hemisphere (both hemispherically and in the Asia-Pacific sector) is associated with La Niña conditions and a poleward expansion of the tropical wet zone in the Asia-Pacific sector. While La Niña also promotes expansion in the American and African sectors during austral winter, these tropical conditions tend to promote contraction in the two sectors during austral summer as a result of compensating convergence over the Americas and Africa sectors: a process driven by variations in the Walker circulation and Rossby wave trains emanating from the tropical Indian Ocean.

Future change in ocean productivity: Is the Arctic the new Atlantic?

NASA Astrophysics Data System (ADS)

Yool, A.; Popova, E. E.; Coward, A. C.

2015-12-01

One of the most characteristic features in ocean productivity is the North Atlantic spring bloom. Responding to seasonal increases in irradiance and stratification, surface phytopopulations rise significantly, a pattern that visibly tracks poleward into summer. While blooms also occur in the Arctic Ocean, they are constrained by the sea-ice and strong vertical stratification that characterize this region. However, Arctic sea-ice is currently declining, and forecasts suggest this may lead to completely ice-free summers by the mid-21st century. Such change may open the Arctic up to Atlantic-style spring blooms, and do so at the same time as Atlantic productivity is threatened by climate change-driven ocean stratification. Here we use low and high-resolution instances of a coupled ocean-biogeochemistry model, NEMO-MEDUSA, to investigate productivity. Drivers of present-day patterns are identified, and changes in these across a climate change scenario (IPCC RCP 8.5) are analyzed. We find a globally significant decline in North Atlantic productivity (> -20%) by 2100, and a correspondingly significant rise in the Arctic (> +50%). However, rather than the future Arctic coming to resemble the current Atlantic, both regions are instead transitioning to a common, low nutrient regime. The North Pacific provides a counterexample where nutrients remain high and productivity increases with elevated temperature. These responses to climate change in the Atlantic and Arctic are common between model resolutions, suggesting an independence from resolution for key impacts. However, some responses, such as those in the North Pacific, differ between the simulations, suggesting the reverse and supporting the drive to more fine-scale resolutions. This article was corrected on 5 JAN 2016. See the end of the full text for details.

A Decade of Shear-Wave Splitting Observations in Alaska

NASA Astrophysics Data System (ADS)

Bellesiles, A. K.; Christensen, D. H.; Abers, G. A.; Hansen, R. A.; Pavlis, G. L.; Song, X.

2010-12-01

Over the last decade four PASSCAL experiments have been conducted in different regions of Alaska. ARCTIC, BEAAR and MOOS form a north-south transect across the state, from the Arctic Ocean to Price Williams Sound, while the STEEP experiment is currently deployed to the east of that line in the St Elias Mountains of Southeastern Alaska. Shear-wave splitting observations from these networks in addition to several permanent stations of the Alaska Earthquake Information Center were determined in an attempt to understand mantle flow under Alaska in a variety of different geologic settings. Results show two dominant splitting patterns in Alaska, separated by the subducted Pacific Plate. North of the subducted Pacific Plate fast directions are parallel to the trench (along strike of the subducted Pacific Plate) indicating large scale mantle flow in the northeast-southwest direction with higher anisotropy (splitting times) within the mantle wedge. Within or below the Pacific Plate fast directions are normal to the trench in the direction of Pacific Plate convergence. In addition to these two prominent splitting patterns there are several regions that do not match either of these trends. These more complex regions which include the results from STEEP could be due to several factors including effects from the edge of the Pacific Plate. The increase of station coverage that Earthscope will bring to Alaska will aid in developing a more complete model for anisotropy and mantle flow in Alaska.

Enhanced role of eddies in the Arctic marine biological pump

PubMed Central

Watanabe, Eiji; Onodera, Jonaotaro; Harada, Naomi; Honda, Makio C.; Kimoto, Katsunori; Kikuchi, Takashi; Nishino, Shigeto; Matsuno, Kohei; Yamaguchi, Atsushi; Ishida, Akio; Kishi, Michio J.

2014-01-01

The future conditions of Arctic sea ice and marine ecosystems are of interest not only to climate scientists, but also to economic and governmental bodies. However, the lack of widespread, year-long biogeochemical observations remains an obstacle to understanding the complicated variability of the Arctic marine biological pump. Here we show an early winter maximum of sinking biogenic flux in the western Arctic Ocean and illustrate the importance of shelf-break eddies to biological pumping from wide shelves to adjacent deep basins using a combination of year-long mooring observations and three-dimensional numerical modelling. The sinking flux trapped in the present study included considerable fresh organic material with soft tissues and was an order of magnitude larger than previous estimates. We predict that further reductions in sea ice will promote the entry of Pacific-origin biological species into the Arctic basin and accelerate biogeochemical cycles connecting the Arctic and subarctic oceans. PMID:24862402

DOE Office of Scientific and Technical Information (OSTI.GOV)

Otto-Bliesner, Bette L.; Jahn, Alexandra; Feng, Ran

Under previous reconstructions of late Pliocene boundary conditions, climate models have failed to reproduce the warm sea surface temperatures reconstructed in the North Atlantic. Using a reconstruction of mid-Piacenzian paleogeography that has the Bering Strait and Canadian Arctic Archipelago Straits closed, however, improves the simulation of the proxy-indicated warm sea surface temperatures in the North Atlantic in the Community Climate System Model. We find that the closure of these small Arctic gateways strengthens the Atlantic Meridional Overturning Circulation, by inhibiting freshwater transport from the Pacific to the Arctic Ocean and from the Arctic Ocean to the Labrador Sea, leading tomore » warmer sea surface temperatures in the North Atlantic. In conclusion, this indicates that the state of the Arctic gateways may influence the sensitivity of the North Atlantic climate in complex ways, and better understanding of the state of these Arctic gateways for past time periods is needed.« less

Icthyoplankton Assemblages and Distribution in the Chukchi Sea 2012-2013

NASA Astrophysics Data System (ADS)

Busby, M. S.; Duffy-Anderson, J. T.; Mier, K. L.; Tabisola, H. M.

2016-02-01

There is significant interest in the effects of climate change on the Pacific arctic ecosystem, and in determining relationships between physical drivers and biological response. Ichthyoplankton surveys have become an integral component of ecosystem studies in the Pacific arctic over the past decade. In summer 2012 and 2013, large scale fisheries oceanographic surveys that included ichthyoplankton tows were conducted in the northern Bering and eastern Chukchi Seas as part of the Arctic Ecosystem Integrated Survey (Arctic Eis). Spatial and temporal analyses of fish larvae collected determined that yellowfin sole (Limanda aspera) was the most abundant larval fish caught followed by Arctic cod (Boreogadus saida). Cluster analyses showed L. aspera to be the dominant component of a southern, nearshore assemblage strongly associated with the northward moving Alaska Coastal Current (ACC) characterized by relatively warm-low salinity water. Boreogadus saida larvae dominated a more northern assemblage in close proximity to the ice edge and were more abundant in 2013 than 2012. Collections of pelagic fish eggs determined locations of spawning centers for L. aspera nearshore of the Seward Peninsula and Bering flounder (Hippoglossoides robustus) to the west and offshore from Point Barrow in 2012. Similar but less pronounced trends in egg distribution were observed in 2013. Larvae of the forage fish species capelin (Mallotus villosus) and Arctic sand lance (Ammodytes hexapterus) were important assemblage components in 2012 and 2013 respectively. These patterns in the distribution of eggs and larvae are similar to those observed in other studies. The influence of circulation patterns on the distributions of fish in the Chukchi Sea is being investigated and will be discussed.

An extreme Arctic cyclone in August 2016 and its predictability on medium-range timescales

NASA Astrophysics Data System (ADS)

Yamagami, Akio; Matsueda, Mio; Tanaka, Hiroshi

2017-04-01

An extremely strong Arctic cyclone (AC) developed in August 2016. The AC exhibited a minimum sea level pressure (SLP) of 967.2 hPa and covered the entire Pacific sector of the Arctic Ocean at 0000UTC on 16 August. At this time the AC was comparable to the strong AC observed in August 2012, in terms of horizontal extent, position, and intensity as measured by SLP. Two processes contributed to the explosive development of the AC: growth due to baroclinic instability, similar to extratropical cyclones, during the early part of the development stage, and later nonlinear development via the merging of upper warm cores. The AC was maintained for more than one month through multiple mergings with cyclones both generated in the Arctic and migrating northward from lower latitudes, as a result of the high cyclone activity in summer 2016. This study also investigated the predictability of the AC using operational medium-range ensemble forecasts: CMC (Canada), ECMWF (EU), JMA (Japan), NCEP (USA), and UKMO (UK), available at the The Interactive Grand Global Ensemble (TIGGE) database. The minimum SLP of the AC at 0000UTC on 16 August was well predicted by ECMWF 6-day, NCEP and UKMO 5-day, CMC 4-day, and JMA 3-day in advance. The predictability of the minimum SLP of the AC in August 2016 was much higher than that of the AC in 2012 August. Whereas most of the members well predicted the cyclogenesis of the AC, the growth due to baroclinic instability was weaker in some members. Even if the baroclinic growth was predicted well, predicted AC did not develop when the nonlinear development via the merging was not predict accurately. The accurate prediction of the processes in both early and later parts of the development stage was important for the accurate prediction of the development of the AC.

Key Findings of the AMAP 2015 Assessment on Black Carbon and Tropospheric Ozone as Arctic Climate Forcers

NASA Astrophysics Data System (ADS)

Quinn, P.

2015-12-01

The Arctic Monitoring and Assessment Programme (AMAP) established an Expert Group on Short-Lived Climate Forcers (SLCFs) in 2009 with the goal of reviewing the state of science surrounding SLCFs in the Arctic and recommending science tasks to improve the state of knowledge and its application to policy-making. In 2011, the result of the Expert Group's work was published in a technical report entitled The Impact of Black Carbon on Arctic Climate (AMAP, 2011). That report focused entirely on black carbon (BC) and co-emitted organic carbon (OC). The SLCFs Expert Group then expanded its scope to include all species co-emitted with BC as well as tropospheric ozone. An assessment report, entitled Black Carbon and Tropospheric Ozone as Arctic Climate Forcers, was published in 2015. The assessment includes summaries of measurement methods and emissions inventories of SLCFs, atmospheric transport of SLCFs to and within the Arctic, modeling methods for estimating the impact of SLCFs on Arctic climate, model-measurement inter-comparisons, trends in concentrations of SLCFs in the Arctic, and a literature review of Arctic radiative forcing and climate response. In addition, three Chemistry Climate Models and five Chemistry Transport Models were used to calculate Arctic burdens of SLCFs and precursors species, radiative forcing, and Arctic temperature response to the forcing. Radiative forcing was calculated for the direct atmospheric effect of BC, BC-snow/ice effect, and cloud indirect effects. Forcing and temperature response associated with different source sectors (Domestic, Energy+Industry+Waste, Transport, Agricultural waste burning, Forest fires, and Flaring) and source regions (United States, Canada, Russia, Nordic Countries, Rest of Europe, East and South Asia, Arctic, mid-latitudes, tropics, southern hemisphere) were calculated. To enable an evaluation of the cost-effectiveness of regional emission mitigation options, the normalized impacts (i.e., impacts per unit emission from each sector and region) were also calculated. Key findings from the 2015 assessment will be presented.

The great 2012 Arctic Ocean summer cyclone enhanced biological productivity on the shelves

PubMed Central

Zhang, Jinlun; Ashjian, Carin; Campbell, Robert; Hill, Victoria; Spitz, Yvette H; Steele, Michael

2014-01-01

[1] A coupled biophysical model is used to examine the impact of the great Arctic cyclone of early August 2012 on the marine planktonic ecosystem in the Pacific sector of the Arctic Ocean (PSA). Model results indicate that the cyclone influences the marine planktonic ecosystem by enhancing productivity on the shelves of the Chukchi, East Siberian, and Laptev seas during the storm. Although the cyclone's passage in the PSA lasted only a few days, the simulated biological effects on the shelves last 1 month or longer. At some locations on the shelves, primary productivity (PP) increases by up to 90% and phytoplankton biomass by up to 40% in the wake of the cyclone. The increase in zooplankton biomass is up to 18% on 31 August and remains 10% on 15 September, more than 1 month after the storm. In the central PSA, however, model simulations indicate a decrease in PP and plankton biomass. The biological gain on the shelves and loss in the central PSA are linked to two factors. (1) The cyclone enhances mixing in the upper ocean, which increases nutrient availability in the surface waters of the shelves; enhanced mixing in the central PSA does not increase productivity because nutrients there are mostly depleted through summer draw down by the time of the cyclone's passage. (2) The cyclone also induces divergence, resulting from the cyclone's low-pressure system that drives cyclonic sea ice and upper ocean circulation, which transports more plankton biomass onto the shelves from the central PSA. The simulated biological gain on the shelves is greater than the loss in the central PSA, and therefore, the production on average over the entire PSA is increased by the cyclone. Because the gain on the shelves is offset by the loss in the central PSA, the average increase over the entire PSA is moderate and lasts only about 10 days. The generally positive impact of cyclones on the marine ecosystem in the Arctic, particularly on the shelves, is likely to grow with increasing summer cyclone activity if the Arctic continues to warm and the ice cover continues to shrink. PMID:26213671

The great 2012 Arctic Ocean summer cyclone enhanced biological productivity on the shelves.

PubMed

Zhang, Jinlun; Ashjian, Carin; Campbell, Robert; Hill, Victoria; Spitz, Yvette H; Steele, Michael

2014-01-01

[1] A coupled biophysical model is used to examine the impact of the great Arctic cyclone of early August 2012 on the marine planktonic ecosystem in the Pacific sector of the Arctic Ocean (PSA). Model results indicate that the cyclone influences the marine planktonic ecosystem by enhancing productivity on the shelves of the Chukchi, East Siberian, and Laptev seas during the storm. Although the cyclone's passage in the PSA lasted only a few days, the simulated biological effects on the shelves last 1 month or longer. At some locations on the shelves, primary productivity (PP) increases by up to 90% and phytoplankton biomass by up to 40% in the wake of the cyclone. The increase in zooplankton biomass is up to 18% on 31 August and remains 10% on 15 September, more than 1 month after the storm. In the central PSA, however, model simulations indicate a decrease in PP and plankton biomass. The biological gain on the shelves and loss in the central PSA are linked to two factors. (1) The cyclone enhances mixing in the upper ocean, which increases nutrient availability in the surface waters of the shelves; enhanced mixing in the central PSA does not increase productivity because nutrients there are mostly depleted through summer draw down by the time of the cyclone's passage. (2) The cyclone also induces divergence, resulting from the cyclone's low-pressure system that drives cyclonic sea ice and upper ocean circulation, which transports more plankton biomass onto the shelves from the central PSA. The simulated biological gain on the shelves is greater than the loss in the central PSA, and therefore, the production on average over the entire PSA is increased by the cyclone. Because the gain on the shelves is offset by the loss in the central PSA, the average increase over the entire PSA is moderate and lasts only about 10 days. The generally positive impact of cyclones on the marine ecosystem in the Arctic, particularly on the shelves, is likely to grow with increasing summer cyclone activity if the Arctic continues to warm and the ice cover continues to shrink.

Future loss of Arctic sea-ice cover could drive a substantial decrease in California's rainfall.

PubMed

Cvijanovic, Ivana; Santer, Benjamin D; Bonfils, Céline; Lucas, Donald D; Chiang, John C H; Zimmerman, Susan

2017-12-05

From 2012 to 2016, California experienced one of the worst droughts since the start of observational records. As in previous dry periods, precipitation-inducing winter storms were steered away from California by a persistent atmospheric ridging system in the North Pacific. Here we identify a new link between Arctic sea-ice loss and the North Pacific geopotential ridge development. In a two-step teleconnection, sea-ice changes lead to reorganization of tropical convection that in turn triggers an anticyclonic response over the North Pacific, resulting in significant drying over California. These findings suggest that the ability of climate models to accurately estimate future precipitation changes over California is also linked to the fidelity with which future sea-ice changes are simulated. We conclude that sea-ice loss of the magnitude expected in the next decades could substantially impact California's precipitation, thus highlighting another mechanism by which human-caused climate change could exacerbate future California droughts.

76 FR 74670 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod Allocations in the Gulf of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-01

... GOA Pacific cod TACs among gear and operation type, based primarily on historical dependency and catch... 83 sector allocations are based on historical dependency, each sector's retained catch history of the...

Parasites as biological tags of marine, freshwater and anadromous fishes in North America from the Tropics to the Arctic.

PubMed

Marcogliese, David J; Jacobson, Kym C

2015-01-01

Parasites have been considered as natural biological tags of marine fish populations in North America for almost 75 years. In the Northwest Atlantic, the most studied species include Atlantic cod (Gadus morhua), Atlantic herring (Clupea harengus) and the redfishes (Sebastes spp.). In the North Pacific, research has centred primarily on salmonids (Oncorhynchus spp.). However, parasites have been applied as tags for numerous other pelagic and demersal species on both the Atlantic and Pacific coasts. Relatively few studies have been undertaken in the Arctic, and these were designed to discriminate anadromous and resident salmonids (Salvelinus spp.). Although rarely applied in fresh waters, parasites have been used to delineate certain fish stocks within the Great Lakes-St Lawrence River basin. Anisakid nematodes and the copepod Sphyrion lumpi frequently prove useful indicators in the Northwest Atlantic, while myxozoan parasites prove very effective on the coast and open seas of the Pacific Ocean. Relative differences in the ability of parasites to discriminate between fish stocks on the Pacific and Atlantic coasts may be due to oceanographic and bathymetric differences between regions. Molecular techniques used to differentiate populations and species of parasites show promise in future applications in the field.

Post-glacial flooding of the Bering Land Bridge dated to 11 cal ka BP based on new geophysical and sediment records

NASA Astrophysics Data System (ADS)

Jakobsson, Martin; Pearce, Christof; Cronin, Thomas M.; Backman, Jan; Anderson, Leif G.; Barrientos, Natalia; Björk, Göran; Coxall, Helen; de Boer, Agatha; Mayer, Larry A.; Mörth, Carl-Magnus; Nilsson, Johan; Rattray, Jayne E.; Stranne, Christian; Semiletov, Igor; O'Regan, Matt

2017-08-01

The Bering Strait connects the Arctic and Pacific oceans and separates the North American and Asian landmasses. The presently shallow ( ˜ 53 m) strait was exposed during the sea level lowstand of the last glacial period, which permitted human migration across a land bridge today referred to as the Bering Land Bridge. Proxy studies (stable isotope composition of foraminifera, whale migration into the Arctic Ocean, mollusc and insect fossils and paleobotanical data) have suggested a range of ages for the Bering Strait reopening, mainly falling within the Younger Dryas stadial (12.9-11.7 cal ka BP). Here we provide new information on the deglacial and post-glacial evolution of the Arctic-Pacific connection through the Bering Strait based on analyses of geological and geophysical data from Herald Canyon, located north of the Bering Strait on the Chukchi Sea shelf region in the western Arctic Ocean. Our results suggest an initial opening at about 11 cal ka BP in the earliest Holocene, which is later than in several previous studies. Our key evidence is based on a well-dated core from Herald Canyon, in which a shift from a near-shore environment to a Pacific-influenced open marine setting at around 11 cal ka BP is observed. The shift corresponds to meltwater pulse 1b (MWP1b) and is interpreted to signify relatively rapid breaching of the Bering Strait and the submergence of the large Bering Land Bridge. Although the precise rates of sea level rise cannot be quantified, our new results suggest that the late deglacial sea level rise was rapid and occurred after the end of the Younger Dryas stadial.

Measurement of Ice-nucleating Particles over the Western North Pacific, Bering Sea, and Arctic Ocean during a R/V Mirai Cruise in 2016

NASA Astrophysics Data System (ADS)

Murata, K.; Tobo, Y.; Taketani, F.; Miyakawa, T.; Kanaya, Y.

2017-12-01

Measurement of ice-nucleating particles (INPs) was performed using aerosol samples collected during a cruise of R/V Mirai across the western North Pacific, Bering Sea, and Arctic Ocean from August to October, 2016. We used the National Institute of Polar Research Cryogenic Refrigerator Applied to Freezing Test (NIPR-CRAFT) device to examine the immersion freezing efficiency of the collected aerosols in the temperature range of -25°C to 0°C and measured the number concentration of atmospheric INPs. The INP concentrations varied over about three orders of magnitude during the cruise. Over the Arctic Ocean (i.e., >70°N), the INPs were <0.08 L-1. In comparison with the Arctic Ocean, INPs were abundant over the Bering Sea and western North Pacific; 0.03-5.5 L-1 during the first half leg and 0.3-41 L-1 during the returning leg. According to on-board measurement of black carbon concentrations and model simulations, extremely high concentrations of INPs during the returning leg would be attributed to transport of smoke from fires in Siberia. Different INP concentrations during the cruise indicates that INPs in marine air can vary dramatically in response to long-range transport of continental aerosols, such as smoke, in addition to local emissions from the sea surface. The observed concentrations of INPs were reasonably well expressed by power law fits with the number concentration of fluorescent biological aerosol particles simultaneously measured with a Waveband Integrated Bioaerosol Sensor (WIBS-4) during the cruise, which suggests that biological aerosol particles may play a role in determining INP populations in the marine air of this case.

Object-based Image Classification of Arctic Sea Ice and Melt Ponds through Aerial Photos

NASA Astrophysics Data System (ADS)

Miao, X.; Xie, H.; Li, Z.; Lei, R.

2013-12-01

The last six years have marked the lowest Arctic summer sea ice extents in the modern era, with a new record summer minimum (3.4 million km2) set on 13 September 2012. It has been predicted that the Arctic could be free of summer ice within the next 25-30. The loss of Arctic summer ice could have serious consequences, such as higher water temperature due to the positive feedback of albedo, more powerful and frequent storms, rising sea levels, diminished habitats for polar animals, and more pollution due to fossil fuel exploitation and/ or increased traffic through the Northwest/ Northeast Passage. In these processes, melt ponds play an important role in Earth's radiation balance since they strongly absorb solar radiation rather than reflecting it as snow and ice do. Therefore, it is necessary to develop the ability of predicting the sea ice/ melt pond extents and space-time evolution, which is pivotal to prepare for the variation and uncertainty of the future environment, political, economic, and military needs. A lot of efforts have been put into Arctic sea ice modeling to simulate sea ice processes. However, these sea ice models were initiated and developed based on limited field surveys, aircraft or satellite image data. Therefore, it is necessary to collect high resolution sea ice aerial photo in a systematic way to tune up, validate, and improve models. Currently there are many sea ice aerial photos available, such as Chinese Arctic Exploration (CHINARE 2008, 2010, 2012), SHEBA 1998 and HOTRAX 2005. However, manually delineating of sea ice and melt pond from these images is time-consuming and labor-intensive. In this study, we use the object-based remote sensing classification scheme to extract sea ice and melt ponds efficiently from 1,727 aerial photos taken during the CHINARE 2010. The algorithm includes three major steps as follows. (1) Image segmentation groups the neighboring pixels into objects according to the similarity of spectral and texture information; (2) random forest ensemble classifier can distinguish the following objects: water, submerged ice, shadow, and ice/snow; and (3) polygon neighbor analysis can further separate melt ponds from submerged ice according to the spatial neighboring relationship. Our results illustrate the spatial distribution and morphological characters of melt ponds in different latitudes of the Arctic Pacific sector. This method can be applied to massive photos and images taken in past years and future years, in deriving the detailed sea ice and melt pond distribution and changes through years.

Evolution of the Northern Rockweed, Fucus distichus, in a Regime of Glacial Cycling: Implications for Benthic Algal Phylogenetics.

PubMed

Laughinghouse, Haywood Dail; Müller, Kirsten M; Adey, Walter H; Lara, Yannick; Young, Robert; Johnson, Gabriel

2015-01-01

Northern hemisphere rockweeds (Fucus) are thought to have evolved in the North Pacific and then spread to the North Atlantic following the opening of the Bering Strait. They have dispersed and widely speciated in the North Atlantic and its tributary seas. Fucus distichus is likely near the ancestral member of this genus, and studies have shown that there are several species/subspecies in this complex (i.e. F. evanescens and F. gardneri). We used phylogenetic and haplotype analyses to test the phylogenetic relationships and biogeography of F. distichus. Our data and subsequent analyses demonstrate that, unlike previous studies that lacked samples from an extensive geographical area of the Arctic and Subarctic, there is a distinct Arctic haplotype that is the source of subspecies in both the North Pacific and North Atlantic. Fucus distichus occupies a low tide zone habitat, and in Arctic/Subarctic regions it is adapted to the severe stress of sea ice coverage and disturbance during many months per year. We hypothesize that the very large geographic area of Arctic and Subarctic rocky shores available to this species during interglacials, supported by large Arctic/Subarctic fringe areas as well as unglaciated refugia during glacial cycles, provided a robust population and gene pool (described by the Thermogeographic Model). This gene pool dilutes that of the more fragmented and area-limited Temperate/Boreal area populations when they are brought together during glacial cycles. We suggest that similar subspecies complexes for a variety of Arctic/Subarctic shore biota should be examined further in this context, rather than arbitrarily being split up into numerous species.

Arctic Ocean Pathways in the 21st century

NASA Astrophysics Data System (ADS)

Aksenov, Yevgeny; van Gennip, Simon J.; Kelly, Stephen J.; Popova, Ekaterina E.; Yool, Andrew

2017-04-01

In the last three decades, changes in the Arctic environment have been occurring at an increasing rate. The opening up of large areas of previously sea ice-covered ocean affects the marine environment with potential impacts on Arctic ecosystems, including through changes in Arctic access, industries and societies. Changes to sea ice and surface winds result in large-scale shifts in ocean circulation and oceanic pathways. This study presents a high-resolution analysis of the projected ocean circulation and pathways of the Arctic water masses across the 21st century. The analysis is based on an eddy-permitting high-resolution global simulation of the ocean general circulation model NEMO (Nucleus for European Modelling of the Ocean) at the 1/4-degree horizontal resolution. The atmospheric forcing is from HadGEM2-ES model output from IPCC Assessment Report 5 (AR5) simulations performed for Coupled Model Intercomparison Project 5 (CMIP5), and follow the Representative Concentration Pathway 8.5 (RCP8.5) scenario. During the 21st century the AO experiences a significant warming, with sea surface temperature increased by in excess of 4 deg. C. Annual mean Arctic sea ice thickness drops to less than 0.5m, and the Arctic Ocean is ice-free in summer from the mid-century. We use an off-line tracer technique to investigate Arctic pathways of the Atlantic and Pacific waters (AW and PW respectively) under this future climate. The AW tracers have been released in the eastern Fram Strait and in the western Barents Sea, whereas the PW tracer has been seeded in the Bering Strait. In the second half of the century the upper 1000 m ocean circulation shows a reduction in the eastward AW flow along the continental slopes towards the Makarov and Canada basins and a deviation of the PW flow away from the Beaufort Sea towards the Siberian coast. Strengthening of Arctic boundary current and intensification of the cyclonic gyre in the Nansen basin of the Arctic Ocean is accompanied by weakening of the current and an anti-cyclonic gyre spin-up in the Makarov Basin. This presents a shift of the Arctic circulation "dipole" and of the Transpolar Drift, with the consequence that the PW flow towards Fram Strait is significantly reduced by the end of the century, weakening the Pacific-Atlantic connection via the Arctic Ocean, and reducing the Arctic freshwater outflow into the North Atlantic. Examination of the simulations suggests that these circulation changes are primarily due to the shift in the wind.

Loss of sea ice in the Arctic.

PubMed

Perovich, Donald K; Richter-Menge, Jacqueline A

2009-01-01

The Arctic sea ice cover is in decline. The areal extent of the ice cover has been decreasing for the past few decades at an accelerating rate. Evidence also points to a decrease in sea ice thickness and a reduction in the amount of thicker perennial sea ice. A general global warming trend has made the ice cover more vulnerable to natural fluctuations in atmospheric and oceanic forcing. The observed reduction in Arctic sea ice is a consequence of both thermodynamic and dynamic processes, including such factors as preconditioning of the ice cover, overall warming trends, changes in cloud coverage, shifts in atmospheric circulation patterns, increased export of older ice out of the Arctic, advection of ocean heat from the Pacific and North Atlantic, enhanced solar heating of the ocean, and the ice-albedo feedback. The diminishing Arctic sea ice is creating social, political, economic, and ecological challenges.

Geology and physiography of the continental margin north of Alaska and implications for the origin of the Canada Basin

USGS Publications Warehouse

Grantz, Arthur; Eittreim, Stephen L.; Whitney, O.T.

1979-01-01

The continental margin north of Alaska is of Atlantic type. It began to form probably in Early Jurassic time but possibly in middle Early Cretaceous time, when the oceanic Canada Basin of the Arctic Ocean is thought to have opened by rifting about a pole of rotation near the Mackenzie Delta. Offsets of the rift along two fracture zones are thought to have divided the Alaskan margin into three sectors of contrasting structure and stratigraphy. In the Barter Island sector on the east and the Chukchi sector on the west the rift was closer to the present northern Alaska mainland than in the Barrow sector, which lies between them. In the Barter Island and Chukchi sectors the continental shelf is underlain by prisms of clastic sedimentary rocks that are inferred to include thick sections of Jurassic and Neocomian (lower Lower Cretaceous) strata of southern provenance. In the intervening Barrow sector the shelf is underlain by relatively thin sections of Jurassic and Neocomian strata derived from northern sources that now lie beneath the outer continental shelf. The rifted continental margin is overlain by a prograded prism of Albian (upper Lower Cretaceous) to Tertiary clastic sedimentary rocks that comprises the continental terrace of the western Beaufort and northern Chukchi Seas. On the south the prism is bounded by Barrow arch, which is a hingeline between the northward-tilted basement surface beneath the continental shelf of the western Beaufort Sea and the southward-tilted Arctic Platform of northern Alaska. The Arctic platform is overlain by shelf clastic and carbonate strata of Mississippian to Cretaceous age, and by Jurassic and Cretaceous clastic strata of the Colville foredeep. Both the Arctic platform and Colville foredeep sequences extend from northern Alaska beneath the northern Chukchi Sea. At Herald fault zone in the central Chukchi Sea they are overthrust by more strongly deformed Cretaceous to Paleozoic sedimentary rocks of Herald arch, which trends northwest from Cape Lisburne. Hope basin, an extensional intracontinental sedimentary basin of Tertiary age, underlies the Chukchi Sea south of Herald arch.

The Arctic sea ice cover of 2016: a year of record-low highs and higher-than-expected lows

NASA Astrophysics Data System (ADS)

Petty, Alek A.; Stroeve, Julienne C.; Holland, Paul R.; Boisvert, Linette N.; Bliss, Angela C.; Kimura, Noriaki; Meier, Walter N.

2018-02-01

The Arctic sea ice cover of 2016 was highly noteworthy, as it featured record low monthly sea ice extents at the start of the year but a summer (September) extent that was higher than expected by most seasonal forecasts. Here we explore the 2016 Arctic sea ice state in terms of its monthly sea ice cover, placing this in the context of the sea ice conditions observed since 2000. We demonstrate the sensitivity of monthly Arctic sea ice extent and area estimates, in terms of their magnitude and annual rankings, to the ice concentration input data (using two widely used datasets) and to the averaging methodology used to convert concentration to extent (daily or monthly extent calculations). We use estimates of sea ice area over sea ice extent to analyse the relative "compactness" of the Arctic sea ice cover, highlighting anomalously low compactness in the summer of 2016 which contributed to the higher-than-expected September ice extent. Two cyclones that entered the Arctic Ocean during August appear to have driven this low-concentration/compactness ice cover but were not sufficient to cause more widespread melt-out and a new record-low September ice extent. We use concentration budgets to explore the regions and processes (thermodynamics/dynamics) contributing to the monthly 2016 extent/area estimates highlighting, amongst other things, rapid ice intensification across the central eastern Arctic through September. Two different products show significant early melt onset across the Arctic Ocean in 2016, including record-early melt onset in the North Atlantic sector of the Arctic. Our results also show record-late 2016 freeze-up in the central Arctic, North Atlantic and the Alaskan Arctic sector in particular, associated with strong sea surface temperature anomalies that appeared shortly after the 2016 minimum (October onwards). We explore the implications of this low summer ice compactness for seasonal forecasting, suggesting that sea ice area could be a more reliable metric to forecast in this more seasonal, "New Arctic", sea ice regime.

Aerosol remote sensing in polar regions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomasi, Claudio; Kokhanovsky, Alexander A.; Lupi, Angelo

Multi-year sets of ground-based sun-photometer measurements conducted at 12 Arctic sites and 9 Antarctic sites were examined to determine daily mean values of aerosol optical thickness τ(λ) at visible and near-infrared wavelengths, from which best-fit values of Ångström's exponent α were calculated. Analysing these data, the monthly mean values of τ(0.50 μm) and α and the relative frequency histograms of the daily mean values of both parameters were determined for winter–spring and summer–autumn in the Arctic and for austral summer in Antarctica. The Arctic and Antarctic covariance plots of the seasonal median values of α versus τ(0.50 μm) showed: (i)more » a considerable increase in τ(0.50 μm) for the Arctic aerosol from summer to winter–spring, without marked changes in α; and (ii) a marked increase in τ(0.50 μm) passing from the Antarctic Plateau to coastal sites, whereas α decreased considerably due to the larger fraction of sea-salt aerosol. Good agreement was found when comparing ground-based sun-photometer measurements of τ(λ) and α at Arctic and Antarctic coastal sites with Microtops measurements conducted during numerous AERONET/MAN cruises from 2006 to 2013 in three Arctic Ocean sectors and in coastal and off-shore regions of the Southern Atlantic, Pacific, and Indian Oceans, and the Antarctic Peninsula. Lidar measurements were also examined to characterise vertical profiles of the aerosol backscattering coefficient measured throughout the year at Ny-Ålesund. Satellite-based MODIS, MISR, and AATSR retrievals of τ(λ) over large parts of the oceanic polar regions during spring and summer were in close agreement with ship-borne and coastal ground-based sun-photometer measurements. An overview of the chemical composition of mode particles is also presented, based on in-situ measurements at Arctic and Antarctic sites. Fourteen log-normal aerosol number size-distributions were defined to represent the average features of nuclei, accumulation and coarse mode particles for Arctic haze, summer background aerosol, Asian dust and boreal forest fire smoke, and for various background austral summer aerosol types at coastal and high-altitude Antarctic sites. The main columnar aerosol optical characteristics were determined for all 14 particle modes, based on in-situ measurements of the scattering and absorption coefficients. Diurnally averaged direct aerosol-induced radiative forcing and efficiency were calculated for a set of multimodal aerosol extinction models, using various Bidirectional Reflectance Distribution Function models over vegetation-covered, oceanic and snow-covered surfaces. These gave a reliable measure of the pronounced effects of aerosols on the radiation balance of the surface–atmosphere system over polar regions.« less

Aerosol Remote Sensing in Polar Regions

NASA Technical Reports Server (NTRS)

Tomasi, Claudio; Kokhanovsky, Alexander A.; Lupi, Angelo; Ritter, Christoph; Smirnov, Alexander; O'Neill, Norman T.; Stone, Robert S.; Holben, Brent N.; Nyeki, Stephan; Wehrli, Christoph

2014-01-01

Multi-year sets of ground-based sun-photometer measurements conducted at 12 Arctic sites and 9 Antarctic sites were examined to determine daily mean values of aerosol optical thickness tau(lambda) at visible and near-infrared wavelengths, from which best-fit values of Ångström's exponent alpha were calculated. Analyzing these data, the monthly mean values of tau(0.50 micrometers) and alpha and the relative frequency histograms of the daily mean values of both parameters were determined for winter-spring and summer-autumn in the Arctic and for austral summer in Antarctica. The Arctic and Antarctic covariance plots of the seasonal median values of alpha versus tau(0.50 micrometers) showed: (i) a considerable increase in tau(0.50 micrometers) for the Arctic aerosol from summer to winter-spring, without marked changes in alpha; and (ii) a marked increase in tau(0.50 micrometer) passing from the Antarctic Plateau to coastal sites, whereas alpha decreased considerably due to the larger fraction of sea-salt aerosol. Good agreement was found when comparing ground-based sun-photometer measurements of tau(lambda) and alpha at Arctic and Antarctic coastal sites with Microtops measurements conducted during numerous AERONET/MAN cruises from 2006 to 2013 in three Arctic Ocean sectors and in coastal and off-shore regions of the Southern Atlantic, Pacific, and Indian Oceans, and the Antarctic Peninsula. Lidar measurements were also examined to characterize vertical profiles of the aerosol backscattering coefficient measured throughout the year at Ny-Ålesund. Satellite-based MODIS, MISR, and AATSR retrievals of tau(lambda) over large parts of the oceanic polar regions during spring and summer were in close agreement with ship-borne and coastal ground-based sun-photometer measurements. An overview of the chemical composition of mode particles is also presented, based on in-situ measurements at Arctic and Antarctic sites. Fourteen log-normal aerosol number size-distributions were defined to represent the average features of nuclei, accumulation and coarse mode particles for Arctic haze, summer background aerosol, Asian dust and boreal forest fire smoke, and for various background austral summer aerosol types at coastal and high-altitude Antarctic sites. The main columnar aerosol optical characteristics were determined for all 14 particle modes, based on in-situ measurements of the scattering and absorption coefficients. Diurnally averaged direct aerosol-induced radiative forcing and efficiency were calculated for a set of multimodal aerosol extinction models, using various Bidirectional Reflectance Distribution Function models over vegetation-covered, oceanic and snow-covered surfaces. These gave a reliable measure of the pronounced effects of aerosols on the radiation balance of the surface-atmosphere system over polar regions.

Aerosol remote sensing in polar regions

DOE PAGES

Tomasi, Claudio; Kokhanovsky, Alexander A.; Lupi, Angelo; ...

2015-01-01

Multi-year sets of ground-based sun-photometer measurements conducted at 12 Arctic sites and 9 Antarctic sites were examined to determine daily mean values of aerosol optical thickness τ(λ) at visible and near-infrared wavelengths, from which best-fit values of Ångström's exponent α were calculated. Analysing these data, the monthly mean values of τ(0.50 μm) and α and the relative frequency histograms of the daily mean values of both parameters were determined for winter–spring and summer–autumn in the Arctic and for austral summer in Antarctica. The Arctic and Antarctic covariance plots of the seasonal median values of α versus τ(0.50 μm) showed: (i)more » a considerable increase in τ(0.50 μm) for the Arctic aerosol from summer to winter–spring, without marked changes in α; and (ii) a marked increase in τ(0.50 μm) passing from the Antarctic Plateau to coastal sites, whereas α decreased considerably due to the larger fraction of sea-salt aerosol. Good agreement was found when comparing ground-based sun-photometer measurements of τ(λ) and α at Arctic and Antarctic coastal sites with Microtops measurements conducted during numerous AERONET/MAN cruises from 2006 to 2013 in three Arctic Ocean sectors and in coastal and off-shore regions of the Southern Atlantic, Pacific, and Indian Oceans, and the Antarctic Peninsula. Lidar measurements were also examined to characterise vertical profiles of the aerosol backscattering coefficient measured throughout the year at Ny-Ålesund. Satellite-based MODIS, MISR, and AATSR retrievals of τ(λ) over large parts of the oceanic polar regions during spring and summer were in close agreement with ship-borne and coastal ground-based sun-photometer measurements. An overview of the chemical composition of mode particles is also presented, based on in-situ measurements at Arctic and Antarctic sites. Fourteen log-normal aerosol number size-distributions were defined to represent the average features of nuclei, accumulation and coarse mode particles for Arctic haze, summer background aerosol, Asian dust and boreal forest fire smoke, and for various background austral summer aerosol types at coastal and high-altitude Antarctic sites. The main columnar aerosol optical characteristics were determined for all 14 particle modes, based on in-situ measurements of the scattering and absorption coefficients. Diurnally averaged direct aerosol-induced radiative forcing and efficiency were calculated for a set of multimodal aerosol extinction models, using various Bidirectional Reflectance Distribution Function models over vegetation-covered, oceanic and snow-covered surfaces. These gave a reliable measure of the pronounced effects of aerosols on the radiation balance of the surface–atmosphere system over polar regions.« less

Microbial Biogeography on the Legacies of Historical Events in the Arctic Subsurface Sediments

NASA Astrophysics Data System (ADS)

Han, Dukki; Nam, Seung-Il; Hur, Hor-Gil

2017-04-01

The Arctic marine environment consists of various microbial habitats. The niche preference of microbial assemblages in the Arctic Ocean has been surveyed with the modern environmental change by oceanographic traits such as sea-ice dynamics, current circulation, and sedimentation. The North Pacific inflow from the shallow and narrow Bering Strait is highly susceptible to sea-level fluctuations, and thus the water mass exchange mediated by the history of sea-ice between the North Pacific and the Chukchi Sea in the Arctic Ocean. Over geological timescale, the climate change may provide putative evidences for ecological niche for the Arctic microbial assemblages as well as geological records in response to the paleoclimate change. In the present study, the multidisciplinary approach, based on microbiology, geology, and geochemistry, was applied to survey the microbial assemblages in the Arctic subsurface sediments and help further integrate the microbial biogeography and biogeochemical patterns in the Arctic subsurface biosphere. Our results describe microbial assemblages with high-resolution paleoceanographic records in the Chukchi Sea sediment core (ARA02B/01A-GC; 5.4 mbsf) to show the processes that drive microbial biogeographic patterns in the Arctic subsurface sediments. We found microbial habitat preferences closely linked to Holocene paleoclimate records as well as geological, geochemical, and microbiological evidence for the inference of the sulphate-methane transition zone (SMTZ) in the Chukchi Sea. Especially, the vertically distributed predominant populations of Gammaproteobacteria and Marine Group II Euryarchaeota in the ARA02B/01A-GC consistent with the patterns of the known global SMTZs and Holocene sedimentary records, suggesting that in-depth microbiological profiles integrated with geological records may be indirectly useful for reconstructing Arctic paleoclimate changes. In the earliest phase of Mid Holocene in the ARA02B/01A-GC with concentrated crenarchaeol (a unique biomarker for Marine Group I Thaumarchaea), the most abundant archaeal population was Marine Group II Euryarchaeota rather than Marine Group I Thaumarchaea, suggesting that the interpretation of archaeal tetraether lipids in subsurface sediments needs careful consideration for paleoceanography. In conclusion, our findings have important implications for the availability of microbial biogeography in the sedimentary record. The present study offers a deeper understanding of the legacies of historical events during the Holocene and implies that the survey of microbial biogeography may be an appropriate tool to monitor potential effects from the climate change in the Arctic Ocean.

Arctic Research Plan: FY2017-2021

USGS Publications Warehouse

Starkweather, Sandy; Jeffries, Martin O; Stephenson, Simon; Anderson, Rebecca D.; Jones, Benjamin M.; Loehman, Rachel A.; von Biela, Vanessa R.

2016-01-01

The United States is an Arctic nation—Americans depend on the Arctic for biodiversity and climate regulation and for natural resources. America’s Arctic—Alaska—is at the forefront of rapid climate, environmental, and socio-economic changes that are testing the resilience and sustainability of communities and ecosystems. Research to increase fundamental understanding of these changes is needed to inform sound, science-based decision- and policy-making and to develop appropriate solutions for Alaska and the Arctic region as a whole. Created by an Act of Congress in 1984, and since 2010 a subcommittee of the National Science and Technology Council (NSTC) in the Executive Office of the President, the Interagency Arctic Research Policy Committee (IARPC) plays a critical role in advancing scientific knowledge and understanding of the changing Arctic and its impacts far beyond the boundaries of the Arctic. Comprising 14 Federal agencies, offices, and departments, IARPC is responsible for the implementation of a 5-year Arctic Research Plan in consultation with the U.S. Arctic Research Commission, the Governor of the State of Alaska, residents of the Arctic, the private sector, and public interest groups.

Polycyclic aromatic hydrocarbons in ocean sediments from the North Pacific to the Arctic Ocean.

PubMed

Ma, Yuxin; Halsall, Crispin J; Xie, Zhiyong; Koetke, Danijela; Mi, Wenying; Ebinghaus, Ralf; Gao, Guoping

2017-08-01

Eighteen polycyclic aromatic hydrocarbons (PAHs) were measured in surficial sediments along a marine transect from the North Pacific into the Arctic Ocean. The highest average Σ 18 PAHs concentrations were observed along the continental slope of the Canada Basin in the Arctic (68.3 ± 8.5 ng g -1 dw), followed by sediments in the Chukchi Sea shelf (49.7 ± 21.2 ng g -1 dw) and Bering Sea (39.5 ± 11.3 ng g -1 dw), while the Bering Strait (16.8 ± 7.1 ng g -1 dw) and Central Arctic Ocean sediments (13.1 ± 9.6 ng g -1 dw) had relatively lower average concentrations. The use of principal components analysis with multiple linear regression (PCA/MLR) indicated that on average oil related or petrogenic sources contributed ∼42% of the measured PAHs in the sediments and marked by higher concentrations of two methylnaphthalenes over the non-alkylated parent PAH, naphthalene. Wood and coal combustion contributed ∼32%, and high temperature pyrogenic sources contributing ∼26%. Petrogenic sources, such as oil seeps, allochthonous coal and coastally eroded material such as terrigenous sediments particularly affected the Chukchi Sea shelf and slope of the Canada Basin, while biomass and coal combustion sources appeared to have greater influence in the central Arctic Ocean, possibly due to the effects of episodic summertime forest fires. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial variation and low diversity in the major histocompatibility complex in walrus (Odobenus rosmarus)

USGS Publications Warehouse

Sonsthagen, Sarah A.; Fales, Krystal R.; Jay, Chadwick V.; Sage, George K.; Talbot, Sandra L.

2014-01-01

Increased global temperature and associated changes to Arctic habitats will likely result in the northward advance of species, including an influx of pathogens novel to the Arctic. How species respond to these immunological challenges will depend in part on the adaptive potential of their immune response system. We compared levels of genetic diversity at a gene associated with adaptive immune response [Class II major histocompatibility complex (MHC), DQB exon 2] between populations of walrus (Odobenus rosmarus), a sea ice-dependent Arctic species. Walrus was represented by only five MHC DQB alleles, with frequency differences observed between Pacific and Atlantic populations. MHC DQB alleles appear to be under balancing selection, and most (80 %; n = 4/5) of the alleles were observed in walruses from both oceans, suggesting broad scale differences in the frequency of exposure and diversity of pathogens may be influencing levels of heterozygosity at DQB in walruses. Limited genetic diversity at MHC, however, suggests that walrus may have a reduced capacity to respond to novel immunological challenges associated with shifts in ecological communities and environmental stressors predicted for changing climates. This is particularly pertinent for walrus, since reductions in summer sea ice may facilitate both northward expansion of marine species and associated pathogens from more temperate regions, and exchange of marine mammals and associated pathogens through the recently opened Northwest Passage between the Atlantic and Pacific Oceans in the Canadian high Arctic.

The Impact of Transported Pollution on Arctic Climate

NASA Astrophysics Data System (ADS)

Quinn, P.; Stohl, A.; Arneth, A.; Berntsen, T.; Burkhart, J. F.; Flanner, M. G.; Kupiainen, K.; Shepherd, M.; Shevchenko, V. P.; Skov, H.; Vestreng, V.

2011-12-01

Arctic temperatures have increased at almost twice the global average rate over the past 100 years. Warming in the Arctic has been accompanied by an earlier onset of spring melt, a lengthening of the melt season, changes in the mass balance of the Greenland ice sheet, and a decrease in sea ice extent. Short-lived, climate warming pollutants such as black carbon (BC) have recently gained attention as a target for immediate mitigation of Arctic warming in addition to reductions in long lived greenhouse gases. Model calculations indicate that BC increases surface temperatures within the Arctic primarily through deposition on snow and ice surfaces with a resulting decrease in surface albedo and increase in absorbed solar radiation. In 2009, the Arctic Monitoring and Assessment Program (AMAP) established an Expert Group on BC with the goal of identifying source regions and energy sectors that have the largest impact on Arctic climate. Here we present the results of this work and investigate links between mid-latitude pollutants and Arctic climate.

Late Quaternary Variability of Arctic Sea Ice: Insights From Biomarker Proxy Records and Model Simulations

NASA Astrophysics Data System (ADS)

Stein, R. H.; Fahl, K.; Gierz, P.; Niessen, F.; Lohmann, G.

2017-12-01

Over the last about four decades, coinciding with global warming and atmospheric CO2increase, the extent and thickness of Arctic sea ice has decreased dramatically, a decrease much more rapid than predicted by climate models. The driving forces of this change are still not fully understood. In this context, detailed paleoclimatic records going back beyond the timescale of direct observations, i.e., high-resolution Holocene records but also records representing more distant warm periods, may help to to distinguish and quantify more precisely the natural and anthropogenic greenhouse gas forcing of global climate change and related sea ice decrease. Here, we concentrate on sea ice biomarker records representing the penultimate glacial/last interglacial (MIS 6/MIS 5e) and the Holocene time intervals. Our proxy records are compared with climate model simulations using a coupled atmosphere-ocean general circulation model (AOGCM). Based on our data, polynya-type sea ice conditions probably occurred off the major ice sheets along the northern Barents and East Siberian continental margins during late MIS 6. Furthermore, we demonstrate that even during MIS 5e, i.e., a time interval when the high latitudes have been significantly warmer than today, sea ice existed in the central Arctic Ocean during summer, whereas sea ice was significantly reduced along the Barents Sea continental margin influenced by Atlantic Water inflow. Assuming a closed Bering Strait (no Pacific Water inflow) during early MIS 5, model simulations point to a significantly reduced sea ice cover in the central Arctic Ocean, a scenario that is however not supported by the proxy record and thus seems to be less realistic. Our Holocene biomarker proxy records from the Chukchi Sea indicate that main factors controlling the millennial Holocene variability in sea ice are probably changes in surface water and heat flow from the Pacific into the Arctic Ocean as well as the long-term decrease in summer insolation. Here, increased Pacific Water inflow (and heat flux) may have triggered the contemporaneous decrease in sea ice and maximum surface-water productivity during mid-Holocene times.

First oceanographic observations on the Wandel Sea shelf in Northeast Greenland: Tracing the Arctic Ocean outflow through the western Fram Strait

NASA Astrophysics Data System (ADS)

Dmitrenko, Igor A.; Kirillov, Sergei A.; Rudels, Bert; Babb, David G.; Pedersen, Leif T.; Rysgaard, Soeren; Kristoffersen, Yngve; Barber, David G.

2016-04-01

The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in North Eastern Greenland were collected from the land-fast ice in April-May 2015 as a part of the Arctic Science Partnership collaboration during the first research campaign at the Villum Research Station. They were complemented by (i) the ice-tethered profiler (ITP) and Acoustic Dopler Current Profiler (ADCP) mooring observations in ~300 m of the tidewater glacier outlet from the Flade Isblink Ice Cap and (ii) CTDs taken in June-July 2015 along the Wandel Sea continental slope during the Norwegian FRAM 2014-15 sea ice drift. The CTD profiles deeper than 100 m are used to reveal the origin of water masses and determine the extent to which these water masses have interacted with ambient water from the continental slope. The subsurface water layer from ~20-70 m depth is comprised of freshened water (30-32 psu) that is likely associated with the Pacific Water outflow from the Arctic Ocean through the western Fram Strait. The underlying halocline layer centered at ~80 m (~33 psu) separates the Pacific Water layer from a deeper (<140 m) layer of modified Polar Water that has interacted with the warm Atlantic Water outflow through Fram Strait. The Atlantic Water layer with temperature above 0°C is recorded below 140 m. Over the outer shelf, the halocline layer shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient Polar Water mass across the continental slope. Mooring data shows an enhanced shelf-slope interaction responding the storm event in 23-24 April 2015 with northerly winds exceeding 10 m/s. The on-shelf transport of a cold and turbid water from the upper continental slope results in enhanced interleaving within the depth range of the halocline layer (~70-100 m). Our observations of Pacific Water in the Wandel Sea subsurface layer are set in the context of upstream observations in the Beaufort Sea for 2002-2011 and downstream observations from the Northeast Water Polynya (1992-1993), and clearly show the modification of Pacific Water during its advection across the Arctic Ocean from the Bering Strait to Fram Strait. Moreover, the Wandel Sea shelf and continental slope water shows a different water mass structure indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the Western Fram Strait.

Creating collaboration opportunities for marine research across the Arctic: The SEARCH-ACCESS partnership and an emerging sea ice prediction research network

NASA Astrophysics Data System (ADS)

Eicken, H.; Bitz, C. M.; Gascard, J.; Kaminski, T.; Karcher, M. J.; Kauker, F.; Overland, J. E.; Stroeve, J. C.; Wiggins, H. V.

2013-12-01

Rapid Arctic environmental and socio-economic change presents major challenges and opportunities to Arctic residents, government agencies and the private sector. The Arctic Ocean and its ice cover, in particular, are in the midst of transformative change, ranging from declines in sea-ice thickness and summer ice extent to threats to coastal communities and increases in maritime traffic and offshore resource development. The US interagency Study of Environmental Arctic Change (SEARCH) and the European Arctic Climate Change, Economy and Society (ACCESS) project are addressing both scientific research needs and stakeholder information priorities to improve understanding and responses to Arctic change. Capacity building, coordination and integration of activities at the international level and across sectors and stakeholder groups are major challenges that have to be met. ACCESS and SEARCH build on long-standing collaborations with a focus on environmental change in the Arctic ocean-ice-atmosphere system and the most pressing research needs to inform marine policy, resource management and threats to Arctic coastal communities. To illustrate the approach, key results and major conclusions from this international coordination and collaboration effort, we focus on a nascent sea-ice prediction research network. This activity builds on the Arctic Sea Ice Outlook that was initiated by SEARCH and the European DAMOCLES project (a precursor to ACCESS) and has now grown into an international community of practice that synthesizes, evaluates and discusses sea-ice predictions on seasonal to interannual scales. Key goals of the effort which is now entering into a new phase include the comparative evaluation of different prediction approaches, including the combination of different techniques, the compilation of reference datasets and model output, guidance on the design and implementation of observing system efforts to improve predictions and information transfer into private industry and the broader public. The latter relies on informal focus groups convened by ACCESS that help identify stakeholder priorities and provide feedback on science and policy documents resulting from this work. Most important, the research network effort explores the nature and ramifications of sea ice in an ice-diminished Arctic.

Collaborations for Arctic Sea Ice Information and Tools

NASA Astrophysics Data System (ADS)

Sheffield Guy, L.; Wiggins, H. V.; Turner-Bogren, E. J.; Rich, R. H.

2017-12-01

The dramatic and rapid changes in Arctic sea ice require collaboration across boundaries, including between disciplines, sectors, institutions, and between scientists and decision-makers. This poster will highlight several projects that provide knowledge to advance the development and use of sea ice knowledge. Sea Ice for Walrus Outlook (SIWO: https://www.arcus.org/search-program/siwo) - SIWO is a resource for Alaskan Native subsistence hunters and other interested stakeholders. SIWO provides weekly reports, during April-June, of sea ice conditions relevant to walrus in the northern Bering and southern Chukchi seas. Collaboration among scientists, Alaskan Native sea-ice experts, and the Eskimo Walrus Commission is fundamental to this project's success. Sea Ice Prediction Network (SIPN: https://www.arcus.org/sipn) - A collaborative, multi-agency-funded project focused on seasonal Arctic sea ice predictions. The goals of SIPN include: coordinate and evaluate Arctic sea ice predictions; integrate, assess, and guide observations; synthesize predictions and observations; and disseminate predictions and engage key stakeholders. The Sea Ice Outlook—a key activity of SIPN—is an open process to share and synthesize predictions of the September minimum Arctic sea ice extent and other variables. Other SIPN activities include workshops, webinars, and communications across the network. Directory of Sea Ice Experts (https://www.arcus.org/researchers) - ARCUS has undertaken a pilot project to develop a web-based directory of sea ice experts across institutions, countries, and sectors. The goal of the project is to catalyze networking between individual investigators, institutions, funding agencies, and other stakeholders interested in Arctic sea ice. Study of Environmental Arctic Change (SEARCH: https://www.arcus.org/search-program) - SEARCH is a collaborative program that advances research, synthesizes research findings, and broadly communicates the results to support informed decision-making. One of SEARCH's primary science topics is focused on Arctic sea ice; the SEARCH Sea Ice Action Team is leading efforts to advance understanding and awareness of the impacts of Arctic sea-ice loss.

A Review of Pacific Interdecadal Climate Variability: Possible Mechanisms and Surface Climate Signatures in the Pacific Sector

NASA Astrophysics Data System (ADS)

Mantua, N. J.

2004-12-01

Many investigators have examined historical surface climate records from the Pacific sector and identified a relatively small number of spatial patterns varying at decadal to interdecadal time scales. "Pacific Decadal Variability" (PDV) is a label that has been used to describe this family of climate variations. Some patterns of PDV are contained completely within the northern extratropics, while others have signatures throughout the Pacific hemisphere on both sides of the equator. Mechanisms for observed patterns of PDV are not yet known, though a wide variety of hypotheses have been proposed. Various ocean-atmosphere mechanisms for PDV are contained within the extratropics, others within the tropics, while others involve tropical-extratropical interactions. Some investigators have proposed external forcing (solar, lunar, or volcanic) as potentially important for driving PDV. A relatively simple hypothesis couples ENSO forcing with upper ocean heat storage for extratropical PDV, and it suggests PDV predictability may be limited to ~2 year lead times. Paleo-PDV reconstructions have been based on materials throughout the Pacific sector using such things as extratropical tree-rings, tropical corals, extratropical clam shell growth rings, and ice cores. These different proxy records have generally provided different perspectives on paleo-PDV behavior.

The Arctic Vortex in March 2011: A Dynamical Perspective

NASA Technical Reports Server (NTRS)

Hurwitz, Margaret M.; Newman, Paul A.; Garfinkel,Chaim I.

2011-01-01

Despite the record ozone loss observed in March 2011, dynamical conditions in the Arctic stratosphere were unusual but not unprecedented. Weak planetary wave driving in February preceded cold anomalies in t he polar lower stratosphere in March and a relatively late breakup of the Arctic vortex in April. La Nina conditions and the westerly phas e of the quasi-biennial oscillation (QBO) were observed in March 201 1. Though these conditions are generally associated with a stronger vortex in mid-winter, the respective cold anomalies do not persist t hrough March. Therefore, the La Nina and QBO-westerly conditions cannot explain the observed cold anomalies in March 2011. In contrast, po sitive sea surface temperature anomalies in the North Pacific may ha ve contributed to the unusually weak tropospheric wave driving and s trong Arctic vortex in late winter 2011.

Drake passage and central american seaway controls on the distribution of the oceanic carbon reservoir

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fyke, Jeremy G.; D'Orgeville, Marc; Weaver, Andrew J.

2015-05-01

A coupled carbon/climate model is used to explore the impact of Drake Passage opening and Central American Seaway closure on the distribution of carbon in the global oceans. We find that gateway evolution likely played an important role in setting the modern day distribution of oceanic dissolved inorganic carbon (DIC), which is currently characterized by relatively low concentrations in the Atlantic ocean, and high concentrations in the Southern, Indian, and Pacific oceans. In agreement with previous studies, we find a closed Drake Passage in the presence of an open Central American Seaway results in suppressed Atlantic meridional overturning and enhancedmore » southern hemispheric deep convection. Opening of the Drake Passage triggers Antarctic Circumpolar Current flow and a weak Atlantic meridional overturning circulation (AMOC). Subsequent Central American Seaway closure reinforces the AMOC while also stagnating equatorial Pacific subsurface waters. These gateway-derived oceanographic changes are reflected in large shifts to the global distribution of DIC. An initially closed Drake Passage results in high DIC concentrations in the Atlantic and Arctic oceans, and lower DIC concentrations in the Pacific/Indian/Southern oceans. Opening Drake Passage reverses this gradient by lowering mid-depth Atlantic and Arctic DIC concentrations and raising deep Pacific/Indian/Southern Ocean DIC concentrations. Central American Seaway closure further reinforces this trend through additional Atlantic mid-depth DIC decreases, as well as Pacific mid-depth DIC concentration increases, with the net effect being a transition to a modern distribution of oceanic DIC.« less

Interannual Variability of the Atlantic Water in the Arctic Basin

DTIC Science & Technology

1996-01-01

3778-3784, 1987. 4. Anderson L.G., Bjork G., Holby 0., Jones E.P., Kattner G., Kolterman K.P., Liljebad B ., Lindegren R., Rudels B ., Swift J. Water...Res., part A, 36, pp. 475 - 482 , 1989. 6. Antonov J. Recent climatic changes of the vertical thermal structure of the North Atlantic Ocean and the...North Pacific Ocean. - J. of Climate, v.6, pp.1928-1942, 1993. 7. Blinov N.I. and Popkov S.N. About the heat exchange of Atlantic Waters in the Arctic

75 FR 39892 - Fisheries of the Exclusive Economic Zone Off Alaska; Community Development Quota Program

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-13

... Fisheries Act (AFA) trawl catcher/processor sector (otherwise known as the Amendment 80 sector... catcher/processors. Hook-and-line catcher/processors are allocated 48.7 percent of the annual BSAI Pacific... harvest of Pacific cod by hook-and-line catcher/processors, although this is one of the major groundfish...

33 CFR 165.T13-221 - Safety Zone; Arctic Drilling and Support Vessels, Puget Sound, Washington.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Support Vessels, Puget Sound, Washington. 165.T13-221 Section 165.T13-221 Navigation and Navigable Waters... Coast Guard District § 165.T13-221 Safety Zone; Arctic Drilling and Support Vessels, Puget Sound... Sector Puget Sound Captain Of The Port (COTP) Zone as defined in 33 CFR 3.65-10. (b) Regulations. In...

50 CFR Table 47c to Part 679 - Percent of the AFA Inshore Sector's Pollock Allocation, Numbers of Chinook Salmon Used To...

Code of Federal Regulations, 2011 CFR

2011-10-01

... 0.48 Anita J 560532 1913 0.4999 50 30 80 0.22 Arctic Explorer 936302 3388 1.6236 161 96 257 0.73 Arctic Wind 608216 5137 1.1034 110 65 175 0.50 Arcturus 655328 533 1.5450 153 91 244 0.70 Argosy 611365...

Oceanographic Aspects of Recent Changes in the Arctic

NASA Astrophysics Data System (ADS)

Morison, J. H.

2002-12-01

In the Arctic recent decadal-scale changes have marked the atmosphere, ocean, and land. Connections between the oceanographic changes and large-scale atmospheric circulation changes are emerging. Surface atmospheric pressure has shown a declining trend over the Arctic. In the 1990s, the Arctic Ocean circulation took on a more cyclonic character, and the front separating Atlantic-derived waters of the Eurasian Basin and the Pacific-derived waters of the Canadian Basin shifted counterclockwise. The temperature of Atlantic water in the Arctic Ocean reached record levels. The cold halocline, which isolates the surface from the warm Atlantic water, grew thinner disappearing entirely from the Amundsen Basin at one point [Steele and Boyd, 1998]. Arctic sea ice extent has decreased 3% per decade since the 1970s [Parkinson et al., 1999]. Sea ice thickness over much of the Arctic decreased 43% between 1958-1976 and 1993-1997 [Rothrock et al., 1999]. Arctic ecosystems have responded to these changes. Sea ice studies in the late 1990s indicate that the sea ice algal species composition changed from decades before, with the species recently being characterized by more brackish and freshwater forms. Barents Sea fisheries have shifted north following reductions in ice extent. Pacific salmon species have been found entering rivers in the Arctic. There is evidence that this complex of pan-Arctic changes is connected with the rising trend in the Arctic Oscillation (AO) or Northern Hemisphere atmospheric polar vortex in the 1990s. Theoretical evidence that a positive trend in the AO index might be indicative of greenhouse warming raises the possibility that the recent complex of changes is an Arctic characteristic of global climate change. Also, the changes in ice cover manifest a connection between the complex of change and global climate through ice-albedo feedback, by which reductions in ice cover reduce the amount of sunlight reflected from the earth's surface. Another important climate feedback is that the changes in ocean circulation and ice production have increased the amount of relatively fresh surface water exported to the sub-Arctic Seas, increasing stratification there, and arguably reducing the strength of the global thermohaline circulation. Since the mid-1990s the strength of the Polar Vortex (AO) has relaxed partially toward earlier levels. Recent observations show that Arctic Ocean water mass structure has relaxed somewhat towards climatology near the surface but is still changing at depth. The cold halocline has recovered in some areas. This reinforces the notion that the changes in the Arctic are tied to the atmospheric circulation of the whole northern hemisphere. The events of the last 10-15 years suggest ways the Arctic environment may be an indicator and agent of climate change and highlight the importance of a systematic program to observe the changing Arctic. References Parkinson C. L., D. J. Cavalieri, P. Gloersen, H. J. Zwally, and J. C. Comiso, 1999, Arctic sea ice extents, areas, and trends, 1978-1996, J. Geophys. Res., 104, 20,387-20,856. Rothrock, D. A., Y. Yu, and G. A. Maykut, 1999, Thinning of the Arctic sea-ice cover, Geophys. Res. Lett., 26(23), 3469-3472. Steele, M., and T. Boyd, 1998, Retreat of the cold halocline layer in the Arctic Ocean, J. Geophys. Res., 103, 10,419-10,435.

Using NWP to assess the influence of the Arctic atmosphere on midlatitude weather and climate

NASA Astrophysics Data System (ADS)

Semmler, Tido; Jung, Thomas; Kasper, Marta A.; Serrar, Soumia

2018-01-01

The influence of the Arctic atmosphere on Northern Hemisphere midlatitude tropospheric weather and climate is explored by comparing the skill of two sets of 14-day weather forecast experiments using the ECMWF model with and without relaxation of the Arctic atmosphere towards ERA-Interim reanalysis data during the integration. Two pathways are identified along which the Arctic influences midlatitude weather: a pronounced one over Asia and Eastern Europe, and a secondary one over North America. In general, linkages are found to be strongest (weakest) during boreal winter (summer) when the amplitude of stationary planetary waves over the Northern Hemisphere is strongest (weakest). No discernible Arctic impact is found over the North Atlantic and North Pacific region, which is consistent with predominantly southwesterly flow. An analysis of the flow-dependence of the linkages shows that anomalous northerly flow conditions increase the Arctic influence on midlatitude weather over the continents. Specifically, an anomalous northerly flow from the Kara Sea towards West Asia leads to cold surface temperature anomalies not only over West Asia but also over Eastern and Central Europe. Finally, the results of this study are discussed in the light of potential midlatitude benefits of improved Arctic prediction capabilities.

Decadal shifts in autumn migration timing by Pacific Arctic beluga whales are related to delayed annual sea ice formation.

PubMed

Hauser, Donna D W; Laidre, Kristin L; Stafford, Kathleen M; Stern, Harry L; Suydam, Robert S; Richard, Pierre R

2017-06-01

Migrations are often influenced by seasonal environmental gradients that are increasingly being altered by climate change. The consequences of rapid changes in Arctic sea ice have the potential to affect migrations of a number of marine species whose timing is temporally matched to seasonal sea ice cover. This topic has not been investigated for Pacific Arctic beluga whales (Delphinapterus leucas) that follow matrilineally maintained autumn migrations in the waters around Alaska and Russia. For the sympatric Eastern Chukchi Sea ('Chukchi') and Eastern Beaufort Sea ('Beaufort') beluga populations, we examined changes in autumn migration timing as related to delayed regional sea ice freeze-up since the 1990s, using two independent data sources (satellite telemetry data and passive acoustics) for both populations. We compared dates of migration between 'early' (1993-2002) and 'late' (2004-2012) tagging periods. During the late tagging period, Chukchi belugas had significantly delayed migrations (by 2 to >4 weeks, depending on location) from the Beaufort and Chukchi seas. Spatial analyses also revealed that departure from Beaufort Sea foraging regions by Chukchi whales was postponed in the late period. Chukchi beluga autumn migration timing occurred significantly later as regional sea ice freeze-up timing became later in the Beaufort, Chukchi, and Bering seas. In contrast, Beaufort belugas did not shift migration timing between periods, nor was migration timing related to freeze-up timing, other than for southward migration at the Bering Strait. Passive acoustic data from 2008 to 2014 provided independent and supplementary support for delayed migration from the Beaufort Sea (4 day yr -1 ) by Chukchi belugas. Here, we report the first phenological study examining beluga whale migrations within the context of their rapidly transforming Pacific Arctic ecosystem, suggesting flexible responses that may enable their persistence yet also complicate predictions of how belugas may fare in the future. © 2016 John Wiley & Sons Ltd.

Shear-wave splitting observations of mantle anisotropy beneath Alaska

NASA Astrophysics Data System (ADS)

Bellesiles, A. K.; Christensen, D. H.; Entwistle, E.; Litherland, M.; Abers, G. A.; Song, X.

2009-12-01

Observations of seismic anisotropy were obtained from three different PASSCAL broadband experiments throughout Alaska, using shear-wave splitting from teleseismic SKS phases. The MOOS (Multidisciplinary Observations Of Subduction), BEAAR (Broadband Experiment Across the Alaska Range), and ARCTIC (Alaska Receiving Cross-Transects for the Inner Core) networks were used along with selected permanent broadband stations operated by AEIC (Alaska Earthquake Information Center) to produce seismic anisotropy results for the state of Alaska along a north south transect from the active subduction zone in the south, through continental Alaska, to the passive margin in the north. The BEAAR network is in-between the ARCTIC and MOOS networks above the subducting Pacific Plate and mantle wedge and shows a tight ~90 degree rotation of anisotropy above the 70km contour of the subducting plate. The southern stations in BEAAR yield anisotropy results that are subparallel to the Pacific Plate motion as it subducts under North America. These stations have an average fast direction of -45 degrees and 1.03 seconds of delay on average. The MOOS network in south central Alaska yielded similar results with an average fast direction of -30 degrees and delay times of .9 seconds. In the north portion of the BEAAR network the anisotropy is along strike of the subduction zone and has an average fast direction of 27 degrees with an average delay time of 1.4 seconds, although the delay times above the mantle wedge range from 1 to 2.5 seconds and are directly correlated to the length of ray path in the mantle wedge. This general trend NE/SW is seen in the ARCTIC stations to the north although the furthest north stations are oriented more NNE compared to those in BEAAR. The average fast direction for the ARCTIC network is 40 degrees with an average delay time of 1.05 seconds. These results show two distinct orientations of anisotropy in Alaska separated by the subducting Pacific Plate.

A Tri-Oceanic Perspective: DNA Barcoding Reveals Geographic Structure and Cryptic Diversity in Canadian Polychaetes

PubMed Central

Carr, Christina M.; Hardy, Sarah M.; Brown, Tanya M.; Macdonald, Tara A.; Hebert, Paul D. N.

2011-01-01

Background Although polychaetes are one of the dominant taxa in marine communities, their distributions and taxonomic diversity are poorly understood. Recent studies have shown that many species thought to have broad distributions are actually a complex of allied species. In Canada, 12% of polychaete species are thought to occur in Atlantic, Arctic, and Pacific Oceans, but the extent of gene flow among their populations has not been tested. Methodology/Principal Findings Sequence variation in a segment of the mitochondrial cytochrome c oxidase I (COI) gene was employed to compare morphological versus molecular diversity estimates, to examine gene flow among populations of widespread species, and to explore connectivity patterns among Canada's three oceans. Analysis of 1876 specimens, representing 333 provisional species, revealed 40 times more sequence divergence between than within species (16.5% versus 0.38%). Genetic data suggest that one quarter of previously recognized species actually include two or more divergent lineages, indicating that richness in this region is currently underestimated. Few species with a tri-oceanic distribution showed genetic cohesion. Instead, large genetic breaks occur between Pacific and Atlantic-Arctic lineages, suggesting their long-term separation. High connectivity among Arctic and Atlantic regions and low connectivity with the Pacific further supports the conclusion that Canadian polychaetes are partitioned into two distinct faunas. Conclusions/Significance Results of this study confirm that COI sequences are an effective tool for species identification in polychaetes, and suggest that DNA barcoding will aid the recognition of species overlooked by the current taxonomic system. The consistent geographic structuring within presumed widespread species suggests that historical range fragmentation during the Pleistocene ultimately increased Canadian polychaete diversity and that the coastal British Columbia fauna played a minor role in Arctic recolonization following deglaciation. This study highlights the value of DNA barcoding for providing rapid insights into species distributions and biogeographic patterns in understudied groups. PMID:21829451

The emergence of modern sea ice cover in the Arctic Ocean.

PubMed

Knies, Jochen; Cabedo-Sanz, Patricia; Belt, Simon T; Baranwal, Soma; Fietz, Susanne; Rosell-Melé, Antoni

2014-11-28

Arctic sea ice coverage is shrinking in response to global climate change and summer ice-free conditions in the Arctic Ocean are predicted by the end of the century. The validity of this prediction could potentially be tested through the reconstruction of the climate of the Pliocene epoch (5.33-2.58 million years ago), an analogue of a future warmer Earth. Here we show that, in the Eurasian sector of the Arctic Ocean, ice-free conditions prevailed in the early Pliocene until sea ice expanded from the central Arctic Ocean for the first time ca. 4 million years ago. Amplified by a rise in topography in several regions of the Arctic and enhanced freshening of the Arctic Ocean, sea ice expanded progressively in response to positive ice-albedo feedback mechanisms. Sea ice reached its modern winter maximum extension for the first time during the culmination of the Northern Hemisphere glaciation, ca. 2.6 million years ago.

A Connection from Arctic Stratospheric Ozone to El Niño-Southern Oscillation

NASA Astrophysics Data System (ADS)

Xie, F.

2017-12-01

Antarctic stratospheric ozone depletion is thought to influence the Southern Hemisphere tropospheric climate. Recently, Arctic stratospheric ozone (ASO) variations have been found to affect the middle-high latitude tropospheric climate in the Northern Hemisphere. This paper demonstrates that the impact of ASO can extend to the tropics, with the ASO variations leading El Niño-Southern Oscillation (ENSO) events by about 20 months. Using observations, analysis, and simulations, the connection between ASO and ENSO is established by combining the high-latitude stratosphere to troposphere pathway with the extratropical to tropical climate teleconnection. This shows that the ASO radiative anomalies influence the North Pacific Oscillation (NPO), and the anomalous NPO and induced Victoria Mode anomalies link to the North Pacific circulation that then influences ENSO. Our results imply that incorporating realistic and time-varying ASO into climate system models may help to improve ENSO predictions.

Freshwater and polynya components of the shelf-derived Arctic Ocean halocline in summer 2007 identified by stable oxygen isotopes

NASA Astrophysics Data System (ADS)

Bauch, D.; Rutgers van der Loeff, M.; Andersen, N.; Torres-Valdes, S.; Bakker, K.; Abrahamsen, E.

2011-12-01

With the aim of determining the origin of freshwater in the halocline, fractions of river water and sea-ice meltwater (or brine influence from sea-ice formation) in the upper 150 m were quantified by a combination of salinity and δ18O and nutrients in the Eurasian basins and the Makarov Basin. Our study indicates which layers of the Arctic Ocean halocline are primarily influenced by sea-ice formation in coastal polynyas and which are primarily influenced by sea-ice formation over the open ocean. With the ongoing changes in sea-ice coverage in the Arctic Ocean it can be expected that these processes will change in the immediate future and that the relative contributions to the halocline will change accordingly. Within the Eurasian Basin a west to east oriented front between net melting and production of sea-ice is observed. Outside the Atlantic regime dominated by net sea-ice melting, a pronounced layer influenced by brines released during sea-ice formation is present at about 30 to 50 m water depth with a maximum over the Lomonosov Ridge. The geographically distinct definition of this maximum demonstrates the rapid release and transport of signals from the shelf regions in discrete pulses within the Transpolar Drift. We use the ratio of sea-ice derived brine influence and river water to link the maximum in brine influence within the Transpolar Drift with a pulse of shelf waters from the Laptev Sea likely released in summer 2005. For a distinction of Atlantic and Pacific-derived contributions the initial phosphate corrected for mineralization with oxygen (PO*) and alternatively the nitrate to phosphate ratio (N/P) in each sample were used. While PO*-based assessments systematically underestimate the contribution of Pacific-derived waters, N/P-based calculations overestimate Pacific-derived waters within the Transpolar Drift due to denitrification in bottom sediments of the Laptev Sea. The extent of Pacific-derived water in the Arctic Ocean was approximately limited by the position of the Lomonosov Ridge in 2007. The ratio of sea-ice derived brine influence and river water is roughly constant within each layer of the Arctic Ocean halocline. The correlation between brine influence and river water reveals two clusters that can be assigned to the two main mechanisms of sea-ice formation within the Arctic Ocean. Over the open ocean or in polynyas at the continental slope sea-ice formation results in a linear correlation between brine influence and river water at salinities of ~ 32 to 34. In coastal polynyas in the shallow regions of the Laptev Sea and southern Kara Sea, sea-ice formation transports river water into the shelf's bottom layer due to the close proximity to the river mouths. This process results in a second linear correlation between brine influence and river water at salinities of ~ 30 to 32.

Diversity of cultured photosynthetic flagellates in the northeast Pacific and Arctic Oceans in summer

NASA Astrophysics Data System (ADS)

Balzano, S.; Gourvil, P.; Siano, R.; Chanoine, M.; Marie, D.; Lessard, S.; Sarno, D.; Vaulot, D.

2012-11-01

During the MALINA cruise (summer 2009), an extensive effort was undertaken to isolate phytoplankton strains from the northeast (NE) Pacific Ocean, the Bering Strait, the Chukchi Sea, and the Beaufort Sea. In order to characterise the main photosynthetic microorganisms occurring in the Arctic during the summer season, strains were isolated by flow cytometry sorting (FCS) and single cell pipetting before or after phytoplankton enrichment of seawater samples. Strains were isolated both onboard and back in the laboratory and cultured at 4 °C under light/dark conditions. Overall, we isolated and characterised by light microscopy and 18 S rRNA gene sequencing 104 strains of photosynthetic flagellates which grouped into 21 genotypes (defined by 99.5% 18 S rRNA gene sequence similarity), mainly affiliated to Chlorophyta and Heterokontophyta. The taxon most frequently isolated was an Arctic ecotype of the green algal genus Micromonas (Arctic Micromonas), which was nearly the only phytoplankter recovered within the picoplankton (< 2 μm) size range. Strains of Arctic Micromonas as well as other strains from the same class (Mamiellophyceae) were identified in further detail by sequencing the internal transcribed spacer (ITS) region of the rRNA operon. The MALINA Micromonas strains share identical 18 S rRNA and ITS sequences suggesting high genetic homogeneity within Arctic Micromonas. Three other Mamiellophyceae strains likely belong to a new genus. Other green algae from the genera Nephroselmis, Chlamydomonas, and Pyramimonas were also isolated, whereas Heterokontophyta included some unidentified Pelagophyceae, Dictyochophyceae (Pedinellales), and Chrysophyceae (Dinobryon faculiferum). Moreover, we isolated some Cryptophyceae (Rhodomonas sp.) as well as a few Prymnesiophyceae and dinoflagellates. We identified the dinoflagellate Woloszynskia cincta by scanning electron microscopy (SEM) and 28 S rRNA gene sequencing. Our morphological analyses show that this species possess the diagnostic features of the genus Biecheleria, and the 28 S rRNA gene topology corroborates this affiliation. We thus propose the transfer of W. cincta to the genus Biecheleria and its recombination as Biecheleria cincta.

Adjustments of a global Finite-Element Sea Ice Ocean Model configuration to improve the general ocean circulation in the North Pacific and its marginal seas.

NASA Astrophysics Data System (ADS)

Scholz, Patrick; Lohmann, Gerrit

2017-04-01

The sub-Arctic oceans like the Sea of Okhotsk, the Bering Sea, the Labrador Sea or the Greenland- Irminger-Norwegian (GIN) Sea react particularly sensitive to global climate changes and have the potential to reversely regulate climate change by CO2 uptake in the other areas of the world. So far, the natural processes in the Arctic and Subarctic system, especially over the Pacific realm, remain poorly understood in terms of numerical modeling. As such, in this study we focus on the North Pacific and its adjacent marginal seas (e.g. the Sea of Okhotsk, the Bering Sea and the Sea of Japan), which have nowadays a significant role in the climate system of the Northwest Pacific by influencing the atmospheric and oceanic circulation as well as the hydrology of the Pacific water masses. The Sea of Okhotsk, in particular, is characterized by a highly dynamical sea-ice coverage, where, in autumn and winter, due to massive sea ice formation and brine rejection, the Sea of Okhotsk Intermediate Water (SOIW) is formed which contributes to the mid-depth (500-1000m) water layer of the North Pacific known as newly formed North Pacific Intermediate Water (NPIW). By employing a Finite-Element Sea-Ice Ocean Model (FESOM), in a global configuration, but with high resolution over the marginal seas of the Northwest Pacific Ocean ( 7 km), we tested different meshes and forcing improvements to correct the general ocean circulation in the North Pacific realm towards a more realistic pattern. By using different forcing data (e.g. CORE2, ERA-40/interim, CCMP-correction), adapting the mesh resolutions in the tropical and subtropical North Pacific and changing the bathymetry over important inflow straits (e.g. Amukta Passage, Kruzenstern Strait), we show that the better results are obtained (when compared with observational data) via a combination of CCMP corrected COREv2 forcing with increased resolution in the pathway of the Kuroshio Extension Current and Northern Equatorial Current.

The Best Modern Analog for Eocene Arctic Forests is within Today's Korean Peninsula

NASA Astrophysics Data System (ADS)

Schubert, B.; Jahren, H.; Eberle, J.; Sternberg, L. O.; Ellsworth, P.; Eberth, D.; Sweet, A.

2011-12-01

In the 25 years that have passed since the first extensive descriptions of the Fossil Forests that persisted above the Arctic Circle during the Eocene (~45-54 Ma), no less than four locations have been suggested as modern analogs. These locations represent a diverse collection of biomes and temperature/precipitation environments, and include the southeastern Unites States and southeastern Asia (based on flora and fauna assemblages), southern Chile and the U.S. Pacific Northwest (based on biomass and productivity estimates), and Pacific Northwestern U.S. and Canada (based on mean annual temperature and mean annual precipitation). Here we report on new isotope datasets that allow for a prediction of best modern analog based on a quantitative characterization of paleoseasonality. First, we report high-resolution carbon isotope data from fossil tree rings that record the ratio of summer to winter precipitation. Second, we report analyses of the oxygen isotope composition of phenylglucosazone, a compound isolated from fossil cellulose that straightforwardly records the oxygen isotope composition of meteoric water available to the tree. Together, our analyses indicate that the fossil forests of the Eocene Arctic thrived under a summer-dominated, high-intensity, seasonal precipitation regime, with at least 279 mm of rainfall during the wettest month. A quantitative comparison of mean-annual temperature and precipitation, fossil and modern plant communities, and the seasonality indices, highlights the Korean peninsula as the most appropriate modern analog for the Arctic Eocene forests, in preference to the North and South American analogs previously proposed.

Provenance of Holocene sediment on the Chukchi-Alaskan margin based on combined diffuse spectral reflectance and quantitative X-Ray Diffraction analysis

USGS Publications Warehouse

Ortiz, J.D.; Polyak, L.; Grebmeier, J.M.; Darby, D.; Eberl, D.D.; Naidu, S.; Nof, D.

2009-01-01

Sediment clay and silt mineral assemblages provide an excellent means of assessing the provenance of fine-grained Arctic sediment especially when a unique mineral assemblage can be tied to specific source areas. The diffuse spectral reflectance (DSR) first derivative measurements and quantitative X-Ray Diffraction (qXRD) on a high-resolution sediment core from the continental slope north of Alaska constrain the sediment mineralogy. DSR results are augmented by measurements on several adjacent cores and compared to surface sediment samples from the northern Alaskan shelf and slope. Using Principal Component Analysis (PCA), we infer that the three leading DSR modes relate to mixtures of smectite + dolomite, illite + goethite, and chlorite + muscovite. This interpretation is consistent with the down core qXRD results. While the smectite + dolomite, and illite + goethite factors show increased variability down core, the chlorite + muscovite factor had highest positive loadings in the middle Holocene, between ca. 6.0 and 3.6??ka. Because the most likely source of the chlorite + muscovite suite in this vicinity lies in the North Pacific, we argue that the oscillations in chlorite + muscovite values likely reflect an increase in the inflow of Pacific water to the Arctic through the Bering Strait. The time interval of this event is associated in other parts of the globe with a non-linear response of the climate system to the decrease in insolation, which may be related to changes in water exchange between the Pacific and Arctic Ocean. ?? 2009 Elsevier B.V.

Synoptic Drivers of Precipitation in the Atlantic Sector of the Arctic

NASA Astrophysics Data System (ADS)

Cohen, L.; Hudson, S.; Graham, R.; Renwick, J. A.

2017-12-01

Precipitation in the Arctic has been shown to be increasing in recent decades, from both observational and modelling studies, with largest trends seen in autumn and winter. This trend is attributed to a combination of the warming atmosphere and reduced sea ice extent. The seasonality of precipitation in the Arctic is important as it largely determines whether the precipitation falls as snow or rain. This study assesses the spatial and temporal variability of the synoptic drivers of precipitation in the Atlantic (European) sector of the Arctic. This region of the Arctic is of particular interest as it has the largest inter-annual variability in sea ice extent and is the primary pathway for moisture transport into the Arctic from lower latitudes. This study uses the ECMWF ERA-I reanalysis total precipitation to compare to long-term precipitation observations from Ny Ålesund, Svalbard to show that the reanalysis captures the synoptic variability of precipitation well and that most precipitation in this region is synoptically driven. The annual variability of precipitation in the Atlantic Arctic shows strong regionality. In the Svalbard and Barents Sea region, most of the annual total precipitation occurs during autumn and winter (Oct-Mar) (>60% of annual total), while the high-Arctic (> 80N) and Kara Sea receives most of the annual precipitation ( 60% of annual total) during summer (July-Sept). Using a synoptic classification developed for this region, this study shows that winter precipitation is driven by winter cyclone occurrence, with strong correlations to the AO and NAO indices. High precipitation over Svalbard is also strongly correlated with the Scandinavian blocking pattern, which produces a southerly flow in the Greenland Sea/Svalbard area. An increasing occurrence of these synoptic patterns are seen for winter months (Nov and Jan), which may explain much of the observed winter increase in precipitation.

Water runoff vs modern climatic warming in mountainous cryolithic zone in North-East Russia

NASA Astrophysics Data System (ADS)

Glotov, V. E.; Glotova, L. P.

2018-01-01

The article presents the results of studying the effects of current climatic warming for both surface and subsurface water runoffs in North-East Russia, where the Main Watershed of the Earth separates it into the Arctic and Pacific continental slopes. The process of climatic warming is testified by continuous weather records during 80-100 years and longer periods. Over the Arctic slope and in the northern areas of the Pacific slope, climatic warming results in a decline in a total runoff of rivers whereas the ground-water recharge becomes greater in winter low-level conditions. In the southern Pacific slope and in the Sea of Okhotsk basin, the effect of climatic warming is an overall increase in total runoff including its subsurface constituents. We believe these peculiar characters of river runoff there to be related to the cryolithic zone environments. Over the Arctic slope and the northern Pacific slope, where cryolithic zone is continuous, the total runoff has its subsurface constituent as basically resulting from discharge of ground waters hosted in seasonally thawing rocks. Warmer climatic conditions favor growth of vegetation that needs more water for the processes of evapotranspiration and evaporation from rocky surfaces in summer seasons. In the Sea of Okhotsk basin, where the cryolithic zone is discontinuous, not only ground waters in seasonally thawing layers, but also continuous taliks and subpermafrost waters participate in processes of river recharges. As a result, a greater biological productivity of vegetation cover does not have any effect on ground-water supply and river recharge processes. If a steady climate warming is provided, a continuous cryolithic zone can presumably degrade into a discontinuous and then into an island-type permafrost layer. Under such a scenario, there will be a general increase in the total runoff and its subsurface constituent. From geoecological viewpoints, a greater runoff will have quite positive effects, whereas some minor negative consequences of it can be successfully prevented.

Remote Linkages to Anomalous Winter Atmospheric Ridging over the Northeastern Pacific

NASA Technical Reports Server (NTRS)

Swain, Daniel L.; Singh, Deepti; Horton, Daniel E.; Mankin, Justin S.; Ballard, Tristan C.; Diffenbaugh, Noah S.

2017-01-01

Severe drought in California between 2013 and 2016 has been linked to the multiyear persistence of anomalously high atmospheric pressure over the northeastern Pacific Ocean, which deflected the Pacific storm track northward and suppressed regional precipitation during California's winter 'rainy season.' Multiple hypotheses have emerged regarding why this high pressure ridge near the west coast of North America was so resilient-including unusual sea surface temperature patterns in the Pacific Ocean, reductions in Arctic sea ice, random atmospheric variability, or some combination thereof. Here we explore relationships between previously documented atmospheric conditions over the North Pacific and several potential remote oceanic and cryospheric influences using both observational data and a large ensemble of climate model simulations. Our results suggest that persistent wintertime atmospheric ridging similar to that implicated in California's 2013-2016 drought can at least partially be linked to unusual Pacific sea surface temperatures, and that Pacific Ocean conditions may offer some degree of cool-season foresight in this region despite the presence of substantial internal variability.

Remote Linkages to Anomalous Winter Atmospheric Ridging Over the Northeastern Pacific

NASA Astrophysics Data System (ADS)

Swain, Daniel L.; Singh, Deepti; Horton, Daniel E.; Mankin, Justin S.; Ballard, Tristan C.; Diffenbaugh, Noah S.

2017-11-01

Severe drought in California between 2013 and 2016 has been linked to the multiyear persistence of anomalously high atmospheric pressure over the northeastern Pacific Ocean, which deflected the Pacific storm track northward and suppressed regional precipitation during California's winter "rainy season." Multiple hypotheses have emerged regarding why this high pressure ridge near the west coast of North America was so resilient—including unusual sea surface temperature patterns in the Pacific Ocean, reductions in Arctic sea ice, random atmospheric variability, or some combination thereof. Here we explore relationships between previously documented atmospheric conditions over the North Pacific and several potential remote oceanic and cryospheric influences using both observational data and a large ensemble of climate model simulations. Our results suggest that persistent wintertime atmospheric ridging similar to that implicated in California's 2013-2016 drought can at least partially be linked to unusual Pacific sea surface temperatures and that Pacific Ocean conditions may offer some degree of cool-season foresight in this region despite the presence of substantial internal variability.

ICESCAPE Mission

NASA Image and Video Library

2010-07-03

Benny Hopson from the Barrow (Alaska) Arctic Science Consortium drills a core sample from sea ice in the Chukchi Sea on July 4, 2010. The core is sliced up into puck-sized sections and stored onboard the U.S. Coast Guard Healy for analysis in the ship's lab. Impacts of Climate change on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) is a multi-year NASA shipborne project. The bulk of the research will take place in the Beaufort and Chukchi Sea’s in summer of 2010 and fall of 2011. Photo Credit: (NASA/Kathryn Hansen)

ICESCAPE Mission

NASA Image and Video Library

2010-07-03

The terrain for the scientific work conducted by ICESCAPE scientists on July 4, 2010, is Arctic sea ice and melt ponds in the Chukchi Sea. The five-week field mission is dedicated to sampling the physical, chemical and biological characteristics of the ocean and sea ice. Impacts of Climate change on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) is a multi-year NASA shipborne project. The bulk of the research will take place in the Beaufort and Chukchi Sea’s in summer of 2010 and fall of 2011. Photo Credit: (NASA/Kathryn Hansen)

The Distributed Biological Observatory (DBO): A Change Detection Array in the Pacific Arctic Region

NASA Astrophysics Data System (ADS)

Grebmeier, J. M.; Moore, S. E.; Cooper, L. W.; Frey, K. E.; Pickart, R. S.

2012-12-01

The Pacific region of the Arctic Ocean is experiencing major reductions in seasonal sea ice extent and increases in sea surface temperatures. One of the key uncertainties in this region is how the marine ecosystem will respond to seasonal shifts in the timing of spring sea ice retreat and/or delays in fall sea ice formation. Climate changes are likely to result in shifts in species composition and abundance, northward range expansions, and changes in lower trophic level productivity that can directly cascade and affect the life cycles of higher trophic level organisms. The developing Distributed Biological Observatory (DBO) is composed of focused biological and oceanographic sampling at biological "hot spot" sites for lower and higher trophic organisms on a latitudinal S-to-N array. The DBO is being developed by an international consortium of scientists in the Pacific Arctic as a change detection array to systematically track the broad biological response to sea ice retreat and associated environmental change. Coordinated ship-based observations over various seasons, together with satellite and mooring data collections at the designated sites, can provide an early detection system for biological and ecosystem response to climate warming. The data documenting the importance of these ecosystem "hotspots" provide a growing marine time-series from the northern Bering Sea to Barrow Canyon at the boundary of the Chukchi and Beaufort seas. Results from these studies show spatial changes in carbon production and export to the sediments as indicated by infaunal community composition and biomass, shifts in sediment grain size on a S-to-N latitudinal gradient, and range extensions for lower trophic levels and further northward migration of higher trophic organisms, such as gray whales. There is also direct evidence of negative impacts on ice dependent species, such as walrus and polar bears. As a ramp up to a fully operational observatory, hydrographic transects and select biological stations have been occupied from spring to fall from 2010-2012 at two DBO locations in the SE Chukchi Sea and Barrow Canyon, providing repeat collections of water column and benthic parameters over the seasons that are unavailable from single cruises. The DBO format is facilitating coordinated efforts for opportunistic, international sampling by ships transiting to the US northern Chukchi Sea in order to develop seasonal time slices of physical, hydrographic, and sentinel plankton, benthos, and higher trophic level measurements. Some example results to be discussed include the freshening and warming as Pacific seawater transits northward over the spring to fall season, with modifications to both plankton and benthic prey bases used by large marine mammals and seabirds. The intent of the DBO is to serve as a change detection array for the identification and consistent monitoring of biophysical responses. Six Pacific countries agreed to participate and share data sets, both real-time and post-cruise, through the Pacific Arctic Group as part of the pilot program and results for this effort will be presented and future plans discussed.

Coal burning leaves toxic heavy metal legacy in the Arctic

DOE Office of Scientific and Technical Information (OSTI.GOV)

McConnell, J.R.; Edwards, R.

2008-08-26

Toxic heavy metals emitted by industrial activities in the midlatitudes are transported through the atmosphere and deposited in the polar regions; bioconcentration and biomagnification in the food chain mean that even low levels of atmospheric deposition may threaten human health and Arctic ecosystems. Little is known about sources and long-term trends of most heavy metals before approximate to 1980, when modern measurements began, although heavy-metal pollution in the Arctic was widespread during recent decades. Lacking detailed, long-term measurements until now, ecologists, health researchers, and policy makers generally have assumed that contamination was highest during the 1960s and 1970s peak ofmore » industrial activity in North America and Europe. We present continuous 1772-2003 monthly and annually averaged deposition records for highly toxic thallium, cadmium, and lead from a Greenland ice core showing that atmospheric deposition was much higher than expected in the early 20th century, with tenfold increases from preindustrial levels by the early 1900s that were two to five times higher than during recent decades. Tracer measurements indicate that coal burning in North America and Europe was the likely source of these metals in the Arctic after 1860. Although these results show that heavy-metal pollution in the North Atlantic sector of the Arctic is substantially lower today than a century ago, contamination of other sectors may be increasing because of the rapid coal-driven growth of Asian economies.« less

Arctic reconstruction from an Alaskan viewpoint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crane, R.C.

1985-04-01

Field, seismic, structural, and stratigraphic data were used to reconstruct the geologic history of the Arctic in 10-m.y. time slices from the present to mid-Jurassic - the initial opening of the Arctic Ocean. A basic assumption is that Lomonosov Ridge, Alpha Ridge, Mendeleyev Ridge, and Chukchi Plateau are all foundered continental plates. Opening of the Arctic occurs in two stages: Late Jurassic - Cretaceous for the Canada basin and Neogene for the Eurasian basin. Opening is facilitated by two subparallel transform shears - the Arctic (Kaltag-Porcupine) on the east and the Chukchi on the west. Deformation is essentially tensional onmore » the Barents side of the Arctic and shear-compressional on the Alaska side. The development of Chutkoya, North Slope, Brooks Range, north-west Canada, Seward Peninsula, and central Alaska can be sequentially related to Arctic opening, modified by impingement on the northern terrane of allochthonous terranes arriving from the south - the Pacific plates of Tintina, Denali, Orca (Prince William-Chugach-Yakutat), Anadyr, Khatyrka, Kolyman, and other minor terranes. The North Slope of Alaska, a passive, rifted, subsided margin, is restored to line up with a similar margin on Alpha Ridge. Northeastern Alaska (the Romanzof Mountain area) lines up opposite the north end of the Sverdrup Rim, near Prince Patrick and Borden Islands.« less

Measurements of the dissolved inorganic carbon system and associated biogeochemical parameters in the Canadian Arctic, 1974-2009

NASA Astrophysics Data System (ADS)

Giesbrecht, K. E.; Miller, L. A.; Davelaar, M.; Zimmermann, S.; Carmack, E.; Johnson, W. K.; Macdonald, R. W.; McLaughlin, F.; Mucci, A.; Williams, W. J.; Wong, C. S.; Yamamoto-Kawai, M.

2014-03-01

We have assembled and conducted primary quality control on previously publicly unavailable water column measurements of the dissolved inorganic carbon system and associated biogeochemical parameters (oxygen, nutrients, etc.) made on 26 cruises in the subarctic and Arctic regions dating back to 1974. The measurements are primarily from the western side of the Canadian Arctic, but also include data that cover an area ranging from the North Pacific to the Gulf of St. Lawrence. The data were subjected to primary quality control (QC) to identify outliers and obvious errors. This data set incorporates over four thousand individual measurements of total inorganic carbon (TIC), alkalinity, and pH from the Canadian Arctic over a period of more than 30 years and provides an opportunity to increase our understanding of temporal changes in the inorganic carbon system in northern waters and the Arctic Ocean. The data set is available for download on the CDIAC (Carbon Dioxide Information Analysis Center) website: http://cdiac.ornl.gov/ftp/oceans/IOS_Arctic_Database/ (doi:10.3334/CDIAC/OTG.IOS_ARCT_CARBN).

Spatial distribution of aquatic marine fungi across the western Arctic and sub-arctic.

PubMed

Hassett, Brandon T; Ducluzeau, Anne-Lise L; Collins, Roy E; Gradinger, Rolf

2017-02-01

Fungi are important parasites of primary producers and nutrient cyclers in aquatic ecosystems. In the Pacific-Arctic domain, fungal parasitism is linked to light intensities and algal stress that can elevate disease incidence on algae and reduce diatom concentrations. Fungi are vastly understudied in the marine realm and knowledge of their function is constrained by the current understanding of fungal distribution and drivers on global scales. To investigate the spatial distribution of fungi in the western Arctic and sub-Arctic, we used high throughput methods to sequence 18S rRNA, cloned and sequenced 28S rRNA and microscopically counted chytrid-infected diatoms. We identified a broad distribution of fungal taxa predominated by Chytridiomycota and Dikarya. Phylogenetic analysis of our Chytridiomycota clones placed Arctic marine fungi sister to the order Lobulomycetales. This clade of fungi predominated in fungal communities under ice with low snowpack. Microscopic examination of fixed seawater and sea ice samples revealed chytrids parasitizing diatoms collected across the Arctic that notably infected 25% of a single diatom species in the Bering Sea. The Pezizomycotina comprised > 95% of eukaryotic sequence reads in Greenland, providing preliminary evidence for osmotrophs being a substitute for algae as the base of food webs. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Air Mass Origin in the Arctic and its Response to Future Warming

NASA Technical Reports Server (NTRS)

Orbe, Clara; Newman, Paul A.; Waugh, Darryn W.; Holzer, Mark; Oman, Luke; Polvani, Lorenzo M.; Li, Feng

2014-01-01

We present the first climatology of air mass origin in the Arctic in terms of rigorously defined air mass fractions that partition air according to where it last contacted the planetary boundary layer (PBL). Results from a present-day climate integration of the GEOSCCM general circulation model reveal that the Arctic lower troposphere below 700 mb is dominated year round by air whose last PBL contact occurred poleward of 60degN, (Arctic air, or air of Arctic origin). By comparison, approx. 63% of the Arctic troposphere above 700 mb originates in the NH midlatitude PBL, (midlatitude air). Although seasonal changes in the total fraction of midlatitude air are small, there are dramatic changes in where that air last contacted the PBL, especially above 700 mb. Specifically, during winter air in the Arctic originates preferentially over the oceans, approx. 26% in the East Pacific, and approx. 20% in the Atlantic PBL. By comparison, during summer air in the Arctic last contacted the midlatitude PBL primarily over land, overwhelmingly so in Asia (approx. 40 %) and, to a lesser extent, in North America (approx. 24%). Seasonal changes in air-mass origin are interpreted in terms of seasonal variations in the large-scale ventilation of the midlatitude boundary layer and lower troposphere, namely changes in the midlatitude tropospheric jet and associated transient eddies during winter and large scale convective motions over midlatitudes during summer.

Effect of Recent Sea Surface Temperature Trends on the Arctic Stratospheric Vortex

NASA Technical Reports Server (NTRS)

Garfinkel, Chaim I.; Oman, Luke; Hurwitz, Margaret

2015-01-01

The springtime Arctic polar vortex has cooled significantly over the satellite era, with consequences for ozone concentrations in the springtime transition season. The causes of this cooling trend are deduced by using comprehensive chemistry-climate model experiments. Approximately half of the satellite era early springtime cooling trend in the Arctic lower stratosphere was caused by changing sea surface temperatures (SSTs). An ensemble of experiments forced only by changing SSTs is compared to an ensemble of experiments in which both the observed SSTs and chemically- and radiatively-active trace species are changing. By comparing the two ensembles, it is shown that warming of Indian Ocean, North Pacific, and North Atlantic SSTs, and cooling of the tropical Pacific, have strongly contributed to recent polar stratospheric cooling in late winter and early spring, and to a weak polar stratospheric warming in early winter. When concentrations of ozone-depleting substances and greenhouse gases are fixed, polar ozone concentrations show a small but robust decline due to changing SSTs. Ozone changes are magnified in the presence of changing gas concentrations. The stratospheric changes can be understood by examining the tropospheric height and heat flux anomalies generated by the anomalous SSTs. Finally, recent SST changes have contributed to a decrease in the frequency of late winter stratospheric sudden warmings.

Variability of Antarctic Sea Ice 1979-1998

NASA Technical Reports Server (NTRS)

Zwally, H. Jay; Comiso, Josefino C.; Parkinson, Claire L.; Cavalieri, Donald J.; Gloersen, Per; Koblinsky, Chester J. (Technical Monitor)

2001-01-01

The principal characteristics of the variability of Antarctic sea ice cover as previously described from satellite passive-microwave observations are also evident in a systematically-calibrated and analyzed data set for 20.2 years (1979-1998). The total Antarctic sea ice extent (concentration > 15 %) increased by 13,440 +/- 4180 sq km/year (+1.18 +/- 0.37%/decade). The area of sea ice within the extent boundary increased by 16,960 +/- 3,840 sq km/year (+1.96 +/- 0.44%/decade). Regionally, the trends in extent are positive in the Weddell Sea (1.5 +/- 0.9%/decade), Pacific Ocean (2.4 +/- 1.4%/decade), and Ross (6.9 +/- 1.1 %/decade) sectors, slightly negative in the Indian Ocean (-1.5 +/- 1.8%/decade, and strongly negative in the Bellingshausen-Amundsen Seas sector (-9.5 +/- 1.5%/decade). For the entire ice pack, small ice increases occur in all seasons with the largest increase during autumn. On a regional basis, the trends differ season to season. During summer and fall, the trends are positive or near zero in all sectors except the Bellingshausen-Amundsen Seas sector. During winter and spring, the trends are negative or near zero in all sectors except the Ross Sea, which has positive trends in all seasons. Components of interannual variability with periods of about 3 to 5 years are regionally large, but tend to counterbalance each other in the total ice pack. The interannual variability of the annual mean sea-ice extent is only 1.6% overall, compared to 5% to 9% in each of five regional sectors. Analysis of the relation between regional sea ice extents and spatially-averaged surface temperatures over the ice pack gives an overall sensitivity between winter ice cover and temperature of -0.7% change in sea ice extent per K. For summer, some regional ice extents vary positively with temperature and others negatively. The observed increase in Antarctic sea ice cover is counter to the observed decreases in the Arctic. It is also qualitatively consistent with the counterintuitive prediction of a global atmospheric-ocean model of increasing sea ice around Antarctica with climate warming due to the stabilizing effects of increased snowfall on the Southern Ocean.

76 FR 74784 - Minto Explorations Ltd. v. Pacific and Arctic Railway and Navigation Company; Notice of Filing of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-01

... Capstone Mining Corp.'' Complainant alleges that Respondent is an Alaska corporation which operates as a... full text of the complaint can be found in the Commission's Electronic Reading Room at http://www.fmc...

Does Funding for Arctic Research Align with Research Priorities and Policy Needs? Trends in the USA, Canada and Europe

NASA Astrophysics Data System (ADS)

Murray, M. S.; Ibarguchi, G.; Rajdev, V.

2015-12-01

Over the past twenty years, increasing awareness and understanding of changes in the Arctic system, the stated desires of Arctic Peoples to be engaged in the research process, and a growing international interest in the region's resources have informed various stakeholders to undertake many Arctic science planning activities. Some examples of science planning include priority-setting for research, knowledge translation, stakeholder engagement, improved coordination, and international collaboration. The International Study of Arctic Change recently initiated an analysis of the extent to which alignment exists among stated science priorities, recognized societal needs, and funding patterns of the major North American and European agencies. In this paper, we present a decade of data on international funding patterns and data on two decades of science planning. We discuss whether funding patterns reflect the priority research questions and identified needs for information that are articulated in a myriad of Arctic research planning documents. The alignment in many areas remains poor, bringing into question the purpose of large-scale science planning if it does not lead to funding of those priorities identified by Arctic stakeholder communities (scientists, Arctic Peoples, planners, policy makers, the private sector, and others).

Seasonal differences in the response of Arctic cyclones to climate change in CESM1

NASA Astrophysics Data System (ADS)

Day, Jonathan J.; Holland, Marika M.; Hodges, Kevin I.

2017-06-01

The dramatic warming of the Arctic over the last three decades has reduced both the thickness and extent of sea ice, opening opportunities for business in diverse sectors and increasing human exposure to meteorological hazards in the Arctic. It has been suggested that these changes in environmental conditions have led to an increase in extreme cyclones in the region, therefore increasing this hazard. In this study, we investigate the response of Arctic synoptic scale cyclones to climate change in a large initial value ensemble of future climate projections with the CESM1-CAM5 climate model (CESM-LE). We find that the response of Arctic cyclones in these simulations varies with season, with significant reductions in cyclone dynamic intensity across the Arctic basin in winter, but with contrasting increases in summer intensity within the region known as the Arctic Ocean cyclone maximum. There is also a significant reduction in winter cyclogenesis events within the Greenland-Iceland-Norwegian sea region. We conclude that these differences in the response of cyclone intensity and cyclogenesis, with season, appear to be closely linked to changes in surface temperature gradients in the high latitudes, with Arctic poleward temperature gradients increasing in summer, but decreasing in winter.

50 CFR 660.323 - Pacific whiting allocations, allocation attainment, and inseason allocation reapportionment.

Code of Federal Regulations, 2010 CFR

2010-10-01

... whiting is allocated among three sectors, as follows:34 percent for the catcher/processor sector; 24 percent for the mothership sector; and 42 percent for the shore-based sector. No more than 5 percent of... primary whiting season north of 42° N. lat.Specific sector allocations for a given calendar year are found...

Exploring the combined effects of the Arctic Oscillation and ENSO on the wintertime climate over East Asia using self-organizing maps

NASA Astrophysics Data System (ADS)

Huang, Wenyu; Chen, Ruyan; Yang, Zifan; Wang, Bin; Ma, Wenqian

2017-09-01

To examine the combined effects of the different spatial patterns of the Arctic Oscillation (AO)-related sea level pressure (SLP) anomalies and the El Niño-Southern Oscillation (ENSO)-related sea surface temperature (SST) anomalies on the wintertime surface temperature anomalies over East Asia, a nonlinear method based on self-organizing maps is employed. Investigation of identified regimes reveals that the AO can affect East Asian temperature anomalies when there are significant SLP anomalies over the Arctic Ocean and northern parts of Eurasian continent. Analogously, ENSO is found to affect East Asian temperature anomalies when significant SST anomalies are present over the tropical central Pacific. The regimes with the warmest and coldest temperature anomalies over East Asia are both associated with the negative phase of the AO. The ENSO-activated, Pacific-East Asian teleconnection pattern could affect the higher latitude continental regions when the impact of the AO is switched off. When the spatial patterns of the AO and ENSO have significant, but opposite, impacts on the coastal winds, no obvious temperature anomalies can be observed over south China. Further, the circulation state with nearly the same AO and Niño3 indices may drive rather different responses in surface temperature over East Asia. The well-known continuous weakening (recovery) of the East Asian winter monsoon that occurred around 1988 (2009) can be attributed to the transitions of the spatial patterns of the SLP anomalies over the Arctic Ocean and Eurasian continent, through their modulation on the occurrences of the Ural and central Siberian blocking events.

Post-glacial flooding of the Bering Land Bridge dated to 11 cal ka BP based on new geophysical and sediment records

USGS Publications Warehouse

Jakobsson, Martin; Pearce, Christof; Cronin, Thomas M.; Backman, Jan; Anderson, Leif G.; Barrientos, Natalia; Bjork, Goran; Coxhall, Helen; de Boer, Agatha; Mayer, Larry; Morth, Carl-Magnus; Nilsson, Johan; Rattray, Jayne; Sranne, Christian; Semiletov, Igor; O'Regan, Matt

2017-01-01

The Bering Strait connects the Arctic and Pacific oceans and separates the North American and Asian landmasses. The presently shallow ( ∼  53 m) strait was exposed during the sea level lowstand of the last glacial period, which permitted human migration across a land bridge today referred to as the Bering Land Bridge. Proxy studies (stable isotope composition of foraminifera, whale migration into the Arctic Ocean, mollusc and insect fossils and paleobotanical data) have suggested a range of ages for the Bering Strait reopening, mainly falling within the Younger Dryas stadial (12.9–11.7 cal ka BP). Here we provide new information on the deglacial and post-glacial evolution of the Arctic–Pacific connection through the Bering Strait based on analyses of geological and geophysical data from Herald Canyon, located north of the Bering Strait on the Chukchi Sea shelf region in the western Arctic Ocean. Our results suggest an initial opening at about 11 cal ka BP in the earliest Holocene, which is later than in several previous studies. Our key evidence is based on a well-dated core from Herald Canyon, in which a shift from a near-shore environment to a Pacific-influenced open marine setting at around 11 cal ka BP is observed. The shift corresponds to meltwater pulse 1b (MWP1b) and is interpreted to signify relatively rapid breaching of the Bering Strait and the submergence of the large Bering Land Bridge. Although the precise rates of sea level rise cannot be quantified, our new results suggest that the late deglacial sea level rise was rapid and occurred after the end of the Younger Dryas stadial.

AMS measurements of 14C and 129I in seawater around radioactive waste dump sites

NASA Astrophysics Data System (ADS)

Povinec, P. P.; Oregioni, B.; Jull, A. J. T.; Kieser, W. E.; Zhao, X.-L.

2000-10-01

According to a recent IAEA compilation of inventories of radioactive wastes dumped in the world ocean, a total of 85 PBq of radioactive wastes were dumped, in the Atlantic (45 PBq), the Pacific (1.4 PBq) and the Arctic (38 PBq) Oceans and their marginal seas between 1946 and 1993, mostly in the form of low-level wastes. 3H, and 14C formed an important part of the beta-activity of these dumped wastes. Because of its long half-life, 14C will be the main constituent in possible leakages from the wastes in the future. On the other hand, 14C and 129I are important radioactive tracers which have been artificially introduced into the oceans. Small amounts of 14C and 129I can be easily measured by accelerator mass spectrometry (AMS) on mg-size samples of carbon and iodine extracted from 500 ml seawater samples. The high analytical sensitivity enables one therefore to find even trace amounts of 14C and 129I which could be released from radioactive wastes, and to compare the measured levels with the global distribution of these radionuclides. The IAEAs Marine Environment Laboratory (IAEA-MEL) has been engaged in an assessment program related to radioactive waste dumping in the oceans since 1992 and has participated in several expeditions to the Atlantic, Arctic, Indian and Pacific Oceans to sample seawater, biota and sediment for radiological assessment studies. In the present paper, we report on methods of 14C and 129I measurements in seawater by AMS and present data on the NE Atlantic, the Arctic and the NW Pacific Ocean dumping sites. A small increase of 14C was observed at the NE Atlantic dumping site.

Chromophoric Dissolved Organic Matter across a Marine Distributed Biological Observatory in the Pacific Arctic Region

NASA Astrophysics Data System (ADS)

Berman, S. L.; Frey, K. E.; Shake, K. L.; Cooper, L. W.; Grebmeier, J. M.

2014-12-01

Dissolved organic matter (DOM) plays an important role in marine ecosystems as both a carbon source for the microbial food web (and thus a source of CO2 to the atmosphere) and as a light inhibitor in marine environments. The presence of chromophoric dissolved organic matter (CDOM; the optically active portion of total DOM) can have significant controlling effects on transmittance of sunlight through the water column and therefore on primary production as well as the heat balance of the upper ocean. However, CDOM is also susceptible to photochemical degradation, which decreases the flux of solar radiation that is absorbed. Knowledge of the current spatial and temporal distribution of CDOM in marine environments is thus critical for understanding how ongoing and future changes in climate may impact these biological, biogeochemical, and physical processes. We describe the quantity and quality of CDOM along five key productive transects across a developing Distributed Biological Observatory (DBO) in the Pacific Arctic region. The samples were collected onboard the CCGS Sir Wilfred Laurier in July 2013 and 2014. Monitoring of the variability of CDOM along transects of high productivity can provide important insights into biological and biogeochemical cycling across the region. Our analyses include overall concentrations of CDOM, as well as proxy information such as molecular weight, lability, and source (i.e., autochthonous vs. allochthonous) of organic matter. We utilize these field observations to compare with satellite-derived CDOM concentrations determined from the Aqua MODIS satellite platform, which ultimately provides a spatially and temporally continuous synoptic view of CDOM concentrations throughout the region. Examining the current relationships among CDOM, sea ice variability, biological productivity, and biogeochemical cycling in the Pacific Arctic region will likely provide key insights for how ecosystems throughout the region will respond in future scenarios of climate change.

Change in abundance of pacific brant wintering in alaska: evidence of a climate warming effect?

USGS Publications Warehouse

Ward, David H.; Dau, Christian P.; Tibbitts, T. Lee; Sedinger, James S.; Anderson, Betty A.; Hines, James E.

2009-01-01

Winter distribution of Pacific Flyway brant (Branta bernicla nigricans) has shifted northward from lowtemperate areas to sub-Arctic areas over the last 42 years. We assessed the winter abundance and distribution of brant in Alaska to evaluate whether climate warming may be contributing to positive trends in the most northern of the wintering populations. Mean surface air temperatures during winter at the end of the Alaska Peninsula increased about 1??C between 1963 and 2004, resulting in a 23% reduction in freezing degree days and a 34% decline in the number of days when ice cover prevents birds from accessing food resources. Trends in the wintering population fluctuated with states of the Pacific Decadal Oscillation, increasing during positive (warm) phases and decreasing during negative (cold) phases, and this correlation provides support for the hypothesis that growth in the wintering population of brant in Alaska is linked to climate warming. The size of the wintering population was negatively correlated with the number of days of strong northwesterly winds in November, which suggests that the occurrence of tailwinds favorable for migration before the onset of winter was a key factor in whether brant migrated from Alaska or remained there during winter. Winter distribution of brant on the Alaska Peninsula was highly variable and influenced by ice cover, particularly at the heavily used Izembek Lagoon. Observations of previously marked brant indicated that the Alaska wintering population was composed primarily of birds originating from Arctic breeding colonies that appear to be growing. Numbers of brant in Alaska during winter will likely increase as temperatures rise and ice cover decreases at high latitudes in response to climate warming. ?? The Arctic Institute of North America.

Modulation of the Aleutian-Icelandic Low Seesaw and Its Surface Impacts by the Atlantic Multidecadal Oscillation

NASA Astrophysics Data System (ADS)

Li, F.; Orsolini, Y. J.

2017-12-01

Early studies suggested that the Aleutian-Icelandic low seesaw (AIS) features multidecadal variation. In this study, the multidecadal modulation of the AIS and associated surface climate by the Atlantic Multidecadal Oscillation (AMO) during late winter (February-March) is explored with observational data. It is shown that, in the cold phase of the AMO (AMO|-), a clear AIS is established, while this is not the case in the warm phase of the AMO (AMO|+). The surface climate over Eurasia is significantly influenced by the AMO's modulation of the Aleutian low (AL). For example, the weak AL in AMO|- displays warmer surface temperatures over the entire Far East and along the Russian Arctic coast and into Northern Europe, but only over the Russian Far East in AMO|+. Similarly, precipitation decreases over central Europe with the weak AL in AMO|-, but decreases over northern Europe and increases over southern Europe in AMO|+. The mechanism underlying the influence of AMO|- on the AIS can be described as follows: AMO|- weakens the upward component of the Eliassen-Palm flux along the polar waveguide by reducing atmospheric blocking occurrence over the Euro-Atlantic sector, and hence drives an enhanced stratospheric polar vortex. With the intensified polar night jet, the wave trains originating over the central North Pacific can propagate horizontally through North America and extend into the North Atlantic, favoring an eastward-extended Pacific-North America-Atlantic pattern, and resulting in a significant AIS at the surface during late winter.

Modulation of the Aleutian-Icelandic low seesaw and its surface impacts by the Atlantic Multidecadal Oscillation

NASA Astrophysics Data System (ADS)

Li, Fei; Orsolini, Yvan J.; Wang, Huijun; Gao, Yongqi; He, Shengping

2018-01-01

Early studies suggested that the Aleutian-Icelandic low seesaw (AIS) features multidecadal variation. In this study, the multidecadal modulation of the AIS and associated surface climate by the Atlantic Multidecadal Oscillation (AMO) during late winter (February-March) is explored with observational data. It is shown that, in the cold phase of the AMO (AMO|-), a clear AIS is established, while this is not the case in the warm phase of the AMO (AMO|+). The surface climate over Eurasia is significantly influenced by the AMO's modulation of the Aleutian low (AL). For example, the weak AL in AMO|- displays warmer surface temperatures over the entire Far East and along the Russian Arctic coast and into Northern Europe, but only over the Russian Far East in AMO|+. Similarly, precipitation decreases over central Europe with the weak AL in AMO|-, but decreases over northern Europe and increases over southern Europe in AMO|+. The mechanism underlying the influence of AMO|- on the AIS can be described as follows: AMO|- weakens the upward component of the Eliassen-Palm flux along the polar waveguide by reducing atmospheric blocking occurrence over the Euro-Atlantic sector, and hence drives an enhanced stratospheric polar vortex. With the intensified polar night jet, the wave trains originating over the central North Pacific can propagate horizontally through North America and extend into the North Atlantic, favoring an eastward-extended Pacific-North America-Atlantic pattern, and resulting in a significant AIS at the surface during late winter.

Climate of the Arctic marine environment.

PubMed

Walsh, John E

2008-03-01

The climate of the Arctic marine environment is characterized by strong seasonality in the incoming solar radiation and by tremendous spatial variations arising from a variety of surface types, including open ocean, sea ice, large islands, and proximity to major landmasses. Interannual and decadal-scale variations are prominent features of Arctic climate, complicating the distinction between natural and anthropogenically driven variations. Nevertheless, climate models consistently indicate that the Arctic is the most climatically sensitive region of the Northern Hemisphere, especially near the sea ice margins. The Arctic marine environment has shown changes over the past several decades, and these changes are part of a broader global warming that exceeds the range of natural variability over the past 1000 years. Record minima of sea ice coverage during the past few summers and increased melt from Greenland have important implications for the hydrographic regime of the Arctic marine environment. The recent changes in the atmosphere (temperature, precipitation, pressure), sea ice, and ocean appear to be a coordinated response to systematic variations of the large-scale atmospheric circulation, superimposed on a general warming that is likely associated with increasing greenhouse gases. The changes have been sufficiently large in some sectors (e.g., the Bering/Chukchi Seas) that consequences for marine ecosystems appear to be underway. Global climate models indicate an additional warming of several degrees Celsius in much of the Arctic marine environment by 2050. However, the warming is seasonal (largest in autumn and winter), spatially variable, and closely associated with further retreat of sea ice. Additional changes predicted for 2050 are a general decrease of sea level pressure (largest in the Bering sector) and an increase of precipitation. While predictions of changes in storminess cannot be made with confidence, the predicted reduction of sea ice cover will almost certainly lead to increased oceanic mixing, ocean wave generation, and coastal flooding.

Towards effective prevention and control of helminth neglected tropical diseases in the Western Pacific Region through multi-disease and multi-sectoral interventions.

PubMed

Nakagawa, Jun; Ehrenberg, John P; Nealon, Joshua; Fürst, Thomas; Aratchige, Padmasiri; Gonzales, Glenda; Chanthavisouk, Chitsavang; Hernandez, Leda M; Fengthong, Tayphasavanh; Utzinger, Jürg; Steinmann, Peter

2015-01-01

Neglected tropical diseases (NTDs) cause serious health, social and economic burdens in the countries of the World Health Organization Western Pacific Region. Among the NTDs, helminth infections are particularly prominent with regard to the number of infected individuals and health impact. Co-endemicity is common among impoverished and marginalized populations. To achieve effective and sustainable control of helminth NTDs, a deeper understanding of the social-ecological systems governing their endemicity and strategies beyond preventive chemotherapy are required to tackle the multiple causes of infection and re-infection. We discuss the feasibility of implementing multi-disease, multi-sectoral intervention packages for helminth NTDs in the Western Pacific Region. After reviewing the main determinants for helminth NTD endemicity and current control strategies, key control activities that involve or concern other programmes within and beyond the health sector are discussed. A considerable number of activities that have an impact on more than one helminth NTD are identified in a variety of sectors, suggesting an untapped potential for synergies. We also highlight the challenges of multi-sectoral collaboration, particularly of involving non-health sectors. We conclude that multi-sectoral collaboration for helminth NTD control is feasible if the target diseases and sectors are carefully selected. To do so, an incentive analysis covering key stakeholders in the sectors is crucial, and the disease-control strategies need to be well understood. The benefits of multi-disease, multi-sectoral approaches could go beyond immediate health impacts by contributing to sustainable development, raising educational attainment, increasing productivity and reducing health inequities. Copyright © 2013 Elsevier B.V. All rights reserved.

Sea Ice Patterns

NASA Image and Video Library

2017-12-08

On July 20, the U.S. Coast Guard Cutter Healy steamed south in the Arctic Ocean toward the edge of the sea ice. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Sipping From a Melt Pond

NASA Image and Video Library

2017-12-08

On July 19, 2011, Zachary Brown of Stanford University sipped freshwater from a melt pond on sea ice in the Arctic ocean. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The Immediacy of Arctic Change

NASA Astrophysics Data System (ADS)

Overland, J. E.; Wang, M.; Soreide, N. N.

2015-12-01

Ongoing temperature changes in the Arctic are large relative to lower latitudes; a process known as Arctic Amplification. Arctic temperatures have increased at least 3 times the rate of mid-latitude temperatures relative to the late 20th century, due to multiple interacting feedbacks driven by modest global change. Even if global temperature increases are contained to +2° C by 2040, Arctic (North of 60° N) monthly mean temperatures in fall will increase by +5° C. The Arctic is very likely to be sea ice free during summer before 2040, with the sea ice free duration limited to <5 months. Snow cover will be absent in May and June on most land masses. Whether these changes impact mid-latitude weather events is complex and controversial, as the time period for observing such linkages is short [<10 years] and involves understanding direct forcing by Arctic changes on a chaotic climatic system. Although chaotic internal variability dominates the dynamics of atmospheric circulation, Arctic thermodynamic influences can reinforce regional weather patterns. Extreme Arctic temperature events, as a combination of mean temperature increases combined with natural variability, will become common, nearing and exceeding previous thresholds. Such an event as an analog for the future was the +4° C anomalies for Alaska in November-December 2014 related to recent warm Pacific sea surface temperatures. Thus for the next few decades out to 2040, continuing rapid environmental changes in the Arctic are very likely, despite any mitigation activities, and the appropriate response is to plan for adaptation to meet these mean and extreme event changes. Mitigation is essential to forestall further disasters in the second half of the century. It is important to note such future rapid Arctic amplification, and the potential for environmental surprises, to support those making planning decisions and encourage action.

Defining and Responding to Issues of Canada's Coastal Zones.

ERIC Educational Resources Information Center

Diamond, Lawrence

1984-01-01

Defines and discusses critical issues for each of Canada's coastal regions (Pacific, Arctic, Atlantic, and Great Lakes) in environmental, technological, social, and political contexts; reviews recent efforts to obtain and use environmental information; and highlights alternative ways of achieving better stewardship. (Author/DH)

50 CFR Table 37 to Part 679 - GOA Amendment 80 Sideboard Limit for Groundfish for the Amendment 80 Sector

Code of Federal Regulations, 2014 CFR

2014-10-01

...% of the TAC. Pacific ocean perch 96.1% of the TAC. Pelagic shelf rockfish 89.6% of the TAC. Central GOA Pacific cod 4.4% of the TAC. Pacific ocean perch Subject to regulations in subpart G to this part... regulations in subpart G to this part. Western GOA Pacific cod 2.0% of the TAC. Pacific ocean perch 99.4% of...

50 CFR Table 37 to Part 679 - GOA Amendment 80 Sideboard Limit for Groundfish for the Amendment 80 Sector

Code of Federal Regulations, 2011 CFR

2011-10-01

...% of the TAC. Pacific ocean perch 96.1% of the TAC. Pelagic shelf rockfish 89.6% of the TAC. Central GOA Pacific cod 4.4% of the TAC. Pacific ocean perch Subject to regulations in subpart G to this part... regulations in subpart G to this part. Western GOA Pacific cod 2.0% of the TAC. Pacific ocean perch 99.4% of...

50 CFR Table 37 to Part 679 - GOA Amendment 80 Sideboard Limit for Groundfish for the Amendment 80 Sector

Code of Federal Regulations, 2010 CFR

2010-10-01

...% of the TAC. Pacific ocean perch 96.1% of the TAC. Pelagic shelf rockfish 89.6% of the TAC. Central GOA Pacific cod 4.4% of the TAC. Pacific ocean perch Subject to regulations in subpart G to this part... regulations in subpart G to this part. Western GOA Pacific cod 2.0% of the TAC. Pacific ocean perch 99.4% of...

50 CFR Table 37 to Part 679 - GOA Amendment 80 Sideboard Limit for Groundfish for the Amendment 80 Sector

Code of Federal Regulations, 2012 CFR

2012-10-01

...% of the TAC. Pacific ocean perch 96.1% of the TAC. Pelagic shelf rockfish 89.6% of the TAC. Central GOA Pacific cod 4.4% of the TAC. Pacific ocean perch Subject to regulations in subpart G to this part... regulations in subpart G to this part. Western GOA Pacific cod 2.0% of the TAC. Pacific ocean perch 99.4% of...

50 CFR Table 37 to Part 679 - GOA Amendment 80 Sideboard Limit for Groundfish for the Amendment 80 Sector

Code of Federal Regulations, 2013 CFR

2013-10-01

...% of the TAC. Pacific ocean perch 96.1% of the TAC. Pelagic shelf rockfish 89.6% of the TAC. Central GOA Pacific cod 4.4% of the TAC. Pacific ocean perch Subject to regulations in subpart G to this part... regulations in subpart G to this part. Western GOA Pacific cod 2.0% of the TAC. Pacific ocean perch 99.4% of...

78 FR 38690 - Aerospace Executive Service Trade Mission at the Singapore Airshow 2014

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-27

... world, serving as an international marketplace and networking platform for the global aerospace... the aerospace industry worldwide. As a leading global aviation hub in Asia Pacific, Singapore (the...-Pacific economies are leading the pace of recovery in the global aviation sector: The Asia-Pacific region...

Bio-optical characteristics along the Straits of Magallanes

NASA Astrophysics Data System (ADS)

Lutz, Vivian; Frouin, Robert; Negri, Rubén; Silva, Ricardo; Pompeu, Mayza; Rudorff, Natalia; Cabral, Anderson; Dogliotti, Ana; Martinez, Gustavo

2016-05-01

The Straits of Magallanes at the tip of South America connects the Atlantic and Pacific Oceans. The variability in the absorption characteristics by phytoplankton (aph(440)), non-pigmented particles, NPP (aNPP(440)), and chromophoric dissolved organic matter, CDOM (ay(440)), measured along the Straits in late summer 2011 (R/V Melville MV1102 cruise), was analyzed. Satellite-derived monthly PAR data showed that at the time of the cruise the western sector was exposed to a low-light environment (~ 16 mol quanta m-2d-1) while the eastern sector received higher irradiance (~ 28 mol quanta m-2d-1). In the Patagonian Shelf total absorption was dominated by phytoplankton (up to 76%; aph(440)=0.265 m-1), while in the Atlantic Sector of the Straits, the major contributor was NPP (up to 42%; aNPP(440)=0.138 m-1), and in the Pacific Sector of the Straits CDOM contributed up to 80% of the total absorption (ay(440)=0.232 m-1). These changes could be related in part to the input of fresh water from glacier melting and rain in the Pacific Sector (ay(440) vs salinity rs=-0.98). The carbon biomass (C) was composed in its majority by pico-phytoplankton and secondly by nano-phytoplankton, with exception of the Atlantic Sector where the micro-phytoplankton dominated. Carbon to chlorophyll-a ratios (C:Chla) were very low throughout the Straits (average of ~ 6) because of photoacclimation to the extremely low light. Complementary pigments data obtained in spring 2003 by the BEAGLE expedition indicated the predominance of diatoms all along the Straits, but the bio-optical trend resembled the one found in late summer 2011, i.e., NPP dominated the absorption in the well mixed Atlantic Sector, phytoplankton in the Middle Sector, and CDOM in the Pacific Sector. These results emphasize that underwater light is the major factor affecting phytoplankton growth and physiology, and that prevalent physical and geochemical conditions play an important role regulating the bio-optical properties in this heterogeneous area. These effects should be considered to adjust parameters (such as C:Chla) when running biogeochemical models for this region.

Geology and tectonic development of the continental margin north of Alaska

USGS Publications Warehouse

Grantz, A.; Eittreim, S.; Dinter, D.A.

1979-01-01

The continental margin north of Alaska, as interpreted from seismic reflection profiles, is of the Atlantic type and consists of three sectors of contrasting structure and stratigraphy. The Chukchi sector, on the west, is characterized by the deep late Mesozoic and Tertiary North Chukchi basin and the Chukchi Continental Borderland. The Barrow sector of central northern Alaska is characterized by the Barrow arch and a moderately thick continental terrace build of Albian to Tertiary clastic sediment. The terrace sedimentary prism is underlain by lower Paleozoic metasedimentary rocks. The Barter Island sector of northeastern Alaska and Yukon Territory is inferred to contain a very thick prism of Jurassic, Cretaceous and Tertiary marine and nonmarine clastic sediment. Its structure is dominated by a local deep Tertiary depocenter and two regional structural arches. We postulate that the distinguishing characteristics of the three sectors are inherited from the configuration of the rift that separated arctic Alaska from the Canadian Arctic Archipelago relative to old pre-rift highlands, which were clastic sediment sources. Where the rift lay relatively close to northern Alaska, in the Chukchi and Barter Island sectors, and locally separated Alaska from the old source terranes, thick late Mesozoic and Tertiary sedimentary prisms extend farther south beneath the continental shelf than in the intervening Barrow sector. The boundary between the Chukchi and Barrow sectors is relatively well defined by geophysical data, but the boundary between the Barrow and Barter Island sectors can only be inferred from the distribution and thickness of Jurassic and Cretaceous sedimentary rocks. These boundaries may be extensions of oceanic fracture zones related to the rifting that is postulated to have opened the Canada Basin, probably beginning during the Early Jurassic. ?? 1979.

Polar bear and walrus response to the rapid decline in Arctic sea ice

USGS Publications Warehouse

Oakley, K.; Whalen, M.; Douglas, David C.; Udevitz, Mark S.; Atwood, Todd C.; Jay, C.

2012-01-01

The Arctic is warming faster than other regions of the world due to positive climate feedbacks associated with loss of snow and ice. One highly visible consequence has been a rapid decline in Arctic sea ice over the past 3 decades - a decline projected to continue and result in ice-free summers likely as soon as 2030. The polar bear (Ursus maritimus) and the Pacific walrus (Odobenus rosmarus divergens) are dependent on sea ice over the continental shelves of the Arctic Ocean's marginal seas. The continental shelves are shallow regions with high biological productivity, supporting abundant marine life within the water column and on the sea floor. Polar bears use sea ice as a platform for hunting ice seals; walruses use sea ice as a resting platform between dives to forage for clams and other bottom-dwelling invertebrates. How have sea ice changes affected polar bears and walruses? How will anticipated changes affect them in the future?

ICESCAPE Mission

NASA Image and Video Library

2010-07-03

Clark University student Christie Wood lowers a water sampler into a borehole on July 4, 2010, to collect water samples from below the Arctic sea ice off the north coast of Alaska. The research is part of NASA's ICESCAPE oceanographic mission to sample the physical, chemical and biological characteristics of the ocean and sea ice. Impacts of Climate change on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) is a multi-year NASA shipborne project. The bulk of the research will take place in the Beaufort and Chukchi Sea’s in summer of 2010 and fall of 2011. Photo Credit: (NASA/Kathryn Hansen)

Diversity of cultured photosynthetic flagellates in the North East Pacific and Arctic Oceans in summer

NASA Astrophysics Data System (ADS)

Balzano, S.; Gourvil, P.; Siano, R.; Chanoine, M.; Marie, D.; Lessard, S.; Sarno, D.; Vaulot, D.

2012-06-01

During the MALINA cruise (summer 2009) an extensive effort was undertaken to isolate phytoplankton strains from the North East (NE) Pacific Ocean, the Bering Strait, and the Beaufort Sea. Strains were isolated by flow cytometry sorting (FCS) and pipetting before or after phytoplankton enrichment of seawater samples. Strains were isolated both onboard and back in the laboratory and cultured at 4 °C under light/dark conditions. Overall, we isolated and characterised by light microscopy and 18S rRNA gene sequencing 104 strains of photosynthetic flagellates which grouped into 21 genotypes (defined by 99.5% 18S rRNA gene sequence similarity) mainly affiliated to Chlorophyta and Heterokontophyta. The taxon most frequently isolated was an Arctic ecotype of the green algal genus Micromonas (Arctic Micromonas) which was almost the only phytoplankter recovered within picoplankton (≤ 2 μm) size range. Strains of Arctic Micromonas as well as three unidentified strains related to the same genus were identified in further details by sequencing the Internal Transcribed Spacer (ITS) region of the rRNA operon. The MALINA Micromonas strains share identical 18S rRNA and ITS sequences suggesting high genetic homogeneity within Arctic Micromonas. The unidentified strains form a genotype likely belonging to a new genus within the family Mamiellaceae to which Micromonas belongs. Other green algae genotypes from the genera Nephroselmis, Chlamydomonas, Pyramimonas were also isolated whereas Heterokontophyta included Pelagophyceae, Dictyochophyceae and Chrysophyceae. Dictyochophyceae included Pedinellales which could not be identified to the genus level whereas Chrysophyceae comprised Dinobryon faculiferum. Moreover, we isolated Rhodomonas sp. as well as a few Haptophyta and dinoflagellates. We identified the dinoflagellate Woloszynskia cincta by Scanning Electron Microscopy (SEM) and 28S rRNA gene sequencing. Our morphological analyses show that this species possess the diagnostic features of the genus Biecheleria, and the 28S rRNA gene topology corroborates this affiliation. We thus propose the transfer of W. cincta to the genus Biecheleria and its recombination as Biecheleria cincta.

76 FR 72681 - Marine Mammals

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-25

.... 15126, issued on May 7, 2010 (75 FR 27300), authorizes the permit holder to take ribbon seals (Phoca fasciata), spotted seals (P. largha), ringed seals (P. hispida), harbor seals (P. vitulina), and bearded seals (Erignathus barbatus) in the North Pacific Ocean, Bering Sea, Arctic Ocean and coastal regions of...

Impacts of ocean albedo alteration on Arctic sea ice restoration and Northern Hemisphere climate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cvijanovic, Ivana; Caldeira, Ken; MacMartin, Douglas G.

The Arctic Ocean is expected to transition into a seasonally ice-free state by mid-century, enhancing Arctic warming and leading to substantial ecological and socio-economic challenges across the Arctic region. It has been proposed that artificially increasing high latitude ocean albedo could restore sea ice, but the climate impacts of such a strategy have not been previously explored. Motivated by this, we investigate the impacts of idealized high latitude ocean albedo changes on Arctic sea ice restoration and climate. In our simulated 4xCO₂ climate, imposing surface albedo alterations over the Arctic Ocean leads to partial sea ice recovery and a modestmore » reduction in Arctic warming. With the most extreme ocean albedo changes, imposed over the area 70°–90°N, September sea ice cover stabilizes at ~40% of its preindustrial value (compared to ~3% without imposed albedo modifications). This is accompanied by an annual mean Arctic surface temperature decrease of ~2 °C but no substantial global mean temperature decrease. Imposed albedo changes and sea ice recovery alter climate outside the Arctic region too, affecting precipitation distribution over parts of the continental United States and Northeastern Pacific. For example, following sea ice recovery, wetter and milder winter conditions are present in the Southwest United States while the East Coast experiences cooling. We conclude that although ocean albedo alteration could lead to some sea ice recovery, it does not appear to be an effective way of offsetting the overall effects of CO₂ induced global warming.« less

Impacts of ocean albedo alteration on Arctic sea ice restoration and Northern Hemisphere climate

DOE PAGES

Cvijanovic, Ivana; Caldeira, Ken; MacMartin, Douglas G.

2015-04-01

The Arctic Ocean is expected to transition into a seasonally ice-free state by mid-century, enhancing Arctic warming and leading to substantial ecological and socio-economic challenges across the Arctic region. It has been proposed that artificially increasing high latitude ocean albedo could restore sea ice, but the climate impacts of such a strategy have not been previously explored. Motivated by this, we investigate the impacts of idealized high latitude ocean albedo changes on Arctic sea ice restoration and climate. In our simulated 4xCO₂ climate, imposing surface albedo alterations over the Arctic Ocean leads to partial sea ice recovery and a modestmore » reduction in Arctic warming. With the most extreme ocean albedo changes, imposed over the area 70°–90°N, September sea ice cover stabilizes at ~40% of its preindustrial value (compared to ~3% without imposed albedo modifications). This is accompanied by an annual mean Arctic surface temperature decrease of ~2 °C but no substantial global mean temperature decrease. Imposed albedo changes and sea ice recovery alter climate outside the Arctic region too, affecting precipitation distribution over parts of the continental United States and Northeastern Pacific. For example, following sea ice recovery, wetter and milder winter conditions are present in the Southwest United States while the East Coast experiences cooling. We conclude that although ocean albedo alteration could lead to some sea ice recovery, it does not appear to be an effective way of offsetting the overall effects of CO₂ induced global warming.« less

Short-cut transport path for Asian dust directly to the Arctic: a case study

NASA Astrophysics Data System (ADS)

Huang, Zhongwei; Huang, Jianping; Hayasaka, Tadahiro; Wang, Shanshan; Zhou, Tian; Jin, Hongchun

2015-11-01

Asian dust can be transported long distances from the Taklimakan or Gobi desert to North America across the Pacific Ocean, and it has been found to have a significant impact on ecosystems, climate, and human health. Although it is well known that Asian dust is transported all over the globe, there are limited observations reporting Asian dust transported to the Arctic. We report a case study of a large-scale heavy dust storm over East Asia on 19 March 2010, as shown by ground-based and space-borne multi-sensor observations, as well as NCEP/NCAR reanalysis data and HYSPLIT trajectories. Our analysis suggests that Asian dust aerosols were transported from northwest China to the Arctic within 5 days, crossing eastern China, Japan and Siberia before reaching the Arctic. The results indicate that Asian dust can be transported for long distances along a previously unreported transport path. Evidence from other dust events over the past decade (2001-2010) also supports our results, indicating that dust from 25.2% of Asian dust events has potentially been transported directly to the Arctic. The transport of Asian dust to the Arctic is due to cyclones and the enhanced East Asia Trough (EAT), which are very common synoptic systems over East Asia. This suggests that many other large dust events would have generated long-range transport of dust to the Arctic along this path in the past. Thus, Asian dust potentially affects the Arctic climate and ecosystem, making climate change in the Arctic much more complex to be fully understood.

Postgraduate Research in Pacific Education: Interpretivism and Other Trends

ERIC Educational Resources Information Center

Burnett, Greg; Lingam, Govinda Ishwar

2012-01-01

This article examines research by postgraduate students in education at the University of the South Pacific (USP) between 1968 and 2009. These experienced educators, who later return to their original education sector to influence policy and practice in some way, are producing new knowledge intimately connected to Pacific education systems. The…

Ice Station Diagrams

NASA Image and Video Library

2017-12-08

On July 18, 2011, Melinda Webster of University of Washington, calculated distances between sampling locations during the 2011 ICESCAPE mission's eighth sea ice station in the Arctic Ocean. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Siberian Arctic black carbon sources constrained by model and observation

PubMed Central

Andersson, August; Eckhardt, Sabine; Stohl, Andreas; Semiletov, Igor P.; Dudarev, Oleg V.; Charkin, Alexander; Shakhova, Natalia; Klimont, Zbigniew; Heyes, Chris; Gustafsson, Örjan

2017-01-01

Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ng⋅m−3 to 302 ng⋅m−3) and dual-isotope–constrained sources (19 to 73% contribution from biomass burning). Comparisons between observations and a dispersion model, coupled to an anthropogenic emissions inventory and a fire emissions inventory, give mixed results. In the European Arctic, this model has proven to simulate BC concentrations and source contributions well. However, the model is less successful in reproducing BC concentrations and sources for the Russian Arctic. Using a Bayesian approach, we show that, in contrast to earlier studies, contributions from gas flaring (6%), power plants (9%), and open fires (12%) are relatively small, with the major sources instead being domestic (35%) and transport (38%). The observation-based evaluation of reported emissions identifies errors in spatial allocation of BC sources in the inventory and highlights the importance of improving emission distribution and source attribution, to develop reliable mitigation strategies for efficient reduction of BC impact on the Russian Arctic, one of the fastest-warming regions on Earth. PMID:28137854

North American Biome

USDA-ARS?s Scientific Manuscript database

The North America biome includes the major ecoregions that make up the land area of Canada, the United States, Mexico, and countries in Central America. The biome is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the s...

Gene flow on ice: the role of sea ice and whaling in shaping Holarctic genetic diversity and population differentiation in bowhead whales (Balaena mysticetus)

PubMed Central

Elizabeth Alter, S; Rosenbaum, Howard C; Postma, Lianne D; Whitridge, Peter; Gaines, Cork; Weber, Diana; Egan, Mary G; Lindsay, Melissa; Amato, George; Dueck, Larry; Brownell, Robert L; Heide-Jørgensen, Mads-Peter; Laidre, Kristin L; Caccone, Gisella; Hancock, Brittany L

2012-01-01

Sea ice is believed to be a major factor shaping gene flow for polar marine organisms, but it remains unclear to what extent it represents a true barrier to dispersal for arctic cetaceans. Bowhead whales are highly adapted to polar sea ice and were targeted by commercial whalers throughout Arctic and subarctic seas for at least four centuries, resulting in severe reductions in most areas. Both changing ice conditions and reductions due to whaling may have affected geographic distribution and genetic diversity throughout their range, but little is known about range-wide genetic structure or whether it differed in the past. This study represents the first examination of genetic diversity and differentiation across all five putative stocks, including Baffin Bay-Davis Strait, Hudson Bay-Foxe Basin, Bering-Beaufort-Chukchi, Okhotsk, and Spitsbergen. We also utilized ancient specimens from Prince Regent Inlet (PRI) in the Canadian Arctic and compared them with modern stocks. Results from analysis of molecular variance and demographic simulations are consistent with recent and high gene flow between Atlantic and Pacific stocks in the recent past. Significant genetic differences between ancient and modern populations suggest PRI harbored unique maternal lineages in the past that have been recently lost, possibly due to loss of habitat during the Little Ice Age and/or whaling. Unexpectedly, samples from this location show a closer genetic relationship with modern Pacific stocks than Atlantic, supporting high gene flow between the central Canadian Arctic and Beaufort Sea over the past millennium despite extremely heavy ice cover over much of this period. PMID:23170222

Late Pliocene paleoeco­logic reconstructions based on ostracode assemblages from the Sagavanirktok and Gubik formations, Alaskan North Slope

USGS Publications Warehouse

Brouwers, Elisabeth M.

1994-01-01

Shallow-marine ostracode assemblages from upper Pliocene sediments of the upper part of the Sagavanirktok Formation and lower part of the Gubik Formation record the last warm period that occurred before the onset of significant cooling of the Arctic Ocean and the initiation of Northern Hemisphere continental glaciation. The informally named Colvillian and Bigbendian transgressions represent the oldest deposits of the Gubik Formation and are dated, based on various lines of evidence, between 2.48 and 3 Ma. Ostracode faunas from the lower part of the Gubik Formation indicate a cold-temperate to subfrigid marine climate with summer bottom temperatures 1-4 C warmer than today. Deposits of the upper part of the Sagavanirktok Formation at Manning Point and Barter Island are older than Colvillian sediments but are believed to be late Pliocene in age and contain an ostracode fauna that has many species in common with the lower part of the Gubik Formation. The Sagavanirktok ostracode faunas indicate a cold-temperature to subfrigid marine climate, similar to that inferred for the lower part of the Gubik Formation, with summer bottom temperatures 1-3 C warmer than today. The opening of Bering Strait at about 3 Ma altered Arctic Ocean assemblage composition as Pacific species migrated into the Arctic and North Atlantic oceans. The admixture of evolutionarily distinct faunas from the Atlantic and Pacific oceans identifies Colvillian (and younger) faunas and provides a convenient reference horizon in the Alaskan fossil record. The marine climatic deterioration that followed the Bigbendian appears to have been abrupt and is documented by biotic turnover, with large numbers of species extinctions and first appearances of new species. The change in species composition can be attributed to the cooling of the Arctic Ocean during the late Pliocene.

The Stress-Strain State of Recent Structures in the Northeastern Sector of the Russian Arctic Region

NASA Astrophysics Data System (ADS)

Imaeva, L. P.; Imaev, V. S.; Mel'nikova, V. I.

2018-03-01

Complex research to determine the stress-strain state of the Earth's crust and the types of seismotectonic destruction for the northeastern sector of the Russian Arctic was conducted. The principles of regional ranking of neotectonic structures were developed according to the activity of geodynamic processes, and argumentation for their class differentiation is presented. The structural-tectonic position, the parameters of the deep structure, the system of active faults, and the tectonic stress fields, calculated on the basis of both tectonophysical analysis of discontinuous and folded late Cenozoic deformations and seismological data, were analyzed. This complex of investigations made it possible to determine the directions of the main axes of deformations of the stress-strain state of the Earth's crust and to reveal the regularity in the change of tectonic regimes.

Arctic Amplification and Potential Mid-Latitude Weather Linkages

NASA Astrophysics Data System (ADS)

Overland, J. E.

2014-12-01

Increasing temperatures and other changes continued in the Arctic over the last decade, even though the rate of global warming has decreased in part due to a cool Pacific Ocean. Thus Arctic temperatures have increased at least 3 times the rate of mid-latitude temperatures. Credibility for persistent Arctic change comes from multiple indicators which are now available for multiple decades. Further, the spatial pattern of Arctic Amplification differs from patterns of natural variability. The role of the Arctic in the global climate system is based on multiple interacting feedbacks represented by these indicators as a causal basis for Arctic Amplification driven by modest global change. Many of these processes act on a regional basis and their non-linear interactions are not well captured by climate models. For example, future loss of sea ice due to increases in CO2 are demonstrated by these models but the rates of loss appear slow. It is reasonable to suspect that Arctic change which can produce the largest temperature anomalies on the planet and demonstrate recent extremes in the polar vortex could be linked to mid-latitude weather, especially as Arctic change will continue over the next decades. The meteorological community remains skeptical, however, in the sense of "not proven." Natural variability in chaotic atmospheric flow remains the main dynamic process, and it is difficult to determine whether Arctic forcing of a north-south linkage is emerging from the most recent period of Arctic change since 2007. Nonetheless, such a hypothesis is worthy of investigation, given the need to further understand Arctic dynamic atmospheric processes, and the potential for improving mid-latitude seasonal forecasts base on high-latitude forcing. Several AGU sessions and other forums over the next year (WWRP, IASC,CliC) address this issue, but the topic is not ready for a firm answer. The very level of controversy indicates the state of the science.

Linear and nonlinear winter atmospheric responses to extreme phases of low frequency Pacific sea surface temperature variability

NASA Astrophysics Data System (ADS)

Cao, Dandan; Wu, Qigang; Hu, Aixue; Yao, Yonghong; Liu, Shizuo; Schroeder, Steven R.; Yang, Fucheng

2018-02-01

This study examines Northern Hemisphere winter (DJFM) atmospheric responses to opposite strong phases of interdecadal (low frequency, LF) Pacific sea surface temperature (SST) forcing, which resembles El Niño-Southern Oscillation (ENSO) on a longer time scale, in observations and GFDL and CAM4 model simulations. Over the Pacific-North America (PNA) sector, linear observed responses of 500-hPa height (Z500) anomalies resemble the PNA teleconnection pattern, but show a PNA-like nonlinear response because of a westward Z500 shift in the negative (LF-) relative to the positive LF (LF+) phase. Significant extratropical linear responses include a North Atlantic Oscillation (NAO)-like Z500 anomaly, a dipole-like Z500 anomaly over northern Eurasia associated with warming over mid-high latitude Eurasia, and a Southern Annular anomaly pattern associated with warming in southern land areas. Significant nonlinear Z500 responses also include a NAO-like anomaly pattern. Models forced by LF+ and LF- SST anomalies reproduce many aspects of observed linear and nonlinear responses over the Pacific-North America sector, and linear responses over southern land, but not in the North Atlantic-European sector and Eurasia. Both models simulate PNA-like linear responses in the North Pacific-North America region similar to observed, but show larger PNA-like LF+ responses, resulting in a PNA nonlinear response. The nonlinear PNA responses result from both nonlinear western tropical Pacific rainfall changes and extratropical transient eddy feedbacks. With LF tropical Pacific forcing only (LFTP+ and LFTP-, climatological SST elsewhere), CAM4 simulates a significant NAO response to LFTP-, including a linear negative and nonlinear positive NAO response.

76 FR 37763 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod Allocations in the Gulf of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-28

...-AY53 Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod Allocations in the Gulf of Alaska... the uncertainty regarding the distribution of Pacific cod catch, enhance stability among the sectors... available for public review and comment. The groundfish fisheries in the exclusive economic zone of the Gulf...

78 FR 43125 - Fisheries off West Coast States; Pacific Coast Groundfish Fishery Management Plan; Commercial...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-19

.../processor trawl fleets (whiting only). Since that time, the Pacific Fishery Management Council (Council) and.... Clarify that the processor obligation may be to more than one MS permit, 10. Revise the mothership catcher... (MS) and Catcher/Processor (C/P) sectors of the Pacific Coast Groundfish fishery. This item was...

Tropical Sectors - NOAA GOES Geostationary Satellite Server

Science.gov Websites

Hurricane IR Image (Pacific) Loop Visible Full Size Hurricane VIS Image (Pacific) Loop Water Vapor Full Size purposes only, they are not considered "operational". This web site should not be used to support

The role of policy in improving diets: experiences from the Pacific Obesity Prevention in Communities food policy project.

PubMed

Thow, A M; Snowdon, W; Schultz, J T; Leeder, S; Vivili, P; Swinburn, B A

2011-11-01

There is global interest in using multisectoral policy approaches to improve diets, and reduce obesity and non-communicable disease. However, there has been ad hoc implementation, which in some sectors such as the economic sector has been very limited, because of the lack of quality evidence on potential costs and impacts, and the inherent challenges associated with cross-sectoral policy development and implementation. The Pacific Obesity Prevention in Communities food policy project aimed to inform relevant policy development and implementation in Pacific Island countries. The project developed an innovative participatory approach to identifying and assessing potential policy options in terms of their effectiveness and feasibility. It also used policy analysis methodology to assess three policy initiatives to reduce fatty meat availability and four soft drink taxes in the region, in order to identify strategies for supporting effective policy implementation. © 2011 The Authors. obesity reviews © 2011 International Association for the Study of Obesity.

Large and giant hydrocarbon accumulations in the transitional continent-ocean zone

NASA Astrophysics Data System (ADS)

Khain, V. E.; Polyakova, I. D.

2008-05-01

The petroleum resource potential is considered for the Atlantic, West Pacific, and East Pacific types of deepwater continental margins. The most considerable energy resources are concentrated at the Atlantic-type passive margins in the zone transitional to the ocean. The less studied continental slope of backarc seas of the generally active margins of the West Pacific type is currently not so rich in discoveries as the Atlantic-type margin, but is not devoid of certain expectations. In some of their parameters, the margins bounded by continental slopes may be regarded as analogs of classical passive margins. At the margins of the East Pacific type, the petroleum potential is solely confined to transform segments. In the shelf-continental-slope basins of the rift and pull-apart nature, petroleum fields occur largely in the upper fan complex, and to a lesser extent in the lower graben (rift) complex. In light of world experience, the shelf-continental-slope basins of the Arctic and Pacific margins of Russia are evaluated as highly promising.

The oceanic biological pump modulates the atmospheric transport of persistent organic pollutants to the Arctic.

PubMed

Galbán-Malagón, Cristóbal; Berrojalbiz, Naiara; Ojeda, María-José; Dachs, Jordi

2012-05-29

Semivolatile persistent organic pollutants have the potential to reach remote environments, such as the Arctic Ocean, through atmospheric transport and deposition. Here we show that this transport of polychlorinated biphenyls to the Arctic Ocean is strongly retarded by the oceanic biological pump. A simultaneous sampling of atmospheric, seawater and plankton samples was performed in July 2007 in the Greenland Current and Atlantic sector of the Arctic Ocean. The atmospheric concentrations declined during atmospheric transport over the Greenland Current with estimated half-lives of 1-4 days. These short half-lives can be explained by the high air-to-water net diffusive flux, which is similar in magnitude to the estimated settling fluxes in the water column. Therefore, the decrease of atmospheric concentrations is due to sequestration of atmospheric polychlorinated biphenyls by enhanced air-water diffusive fluxes driven by phytoplankton uptake and organic carbon settling fluxes (biological pump).

Summers with low Arctic sea ice linked to persistence of spring atmospheric circulation patterns

NASA Astrophysics Data System (ADS)

Kapsch, Marie-Luise; Skific, Natasa; Graversen, Rune G.; Tjernström, Michael; Francis, Jennifer A.

2018-05-01

The declining trend of Arctic September sea ice constitutes a significant change in the Arctic climate system. Large year-to-year variations are superimposed on this sea-ice trend, with the largest variability observed in the eastern Arctic Ocean. Knowledge of the processes important for this variability may lead to an improved understanding of seasonal and long-term changes. Previous studies suggest that transport of heat and moisture into the Arctic during spring enhances downward surface longwave radiation, thereby controlling the annual melt onset, setting the stage for the September ice minimum. In agreement with these studies, we find that years with a low September sea-ice concentration (SIC) are characterized by more persistent periods in spring with enhanced energy flux to the surface in forms of net longwave radiation plus turbulent fluxes, compared to years with a high SIC. Two main atmospheric circulation patterns related to these episodes are identified: one resembles the so-called Arctic dipole anomaly that promotes transport of heat and moisture from the North Pacific, whereas the other is characterized by negative geopotential height anomalies over the Arctic, favoring cyclonic flow from Siberia and the Kara Sea into the eastern Arctic Ocean. However, differences between years with low and high September SIC appear not to be due to different spring circulation patterns; instead it is the persistence and intensity of processes associated with these patterns that distinguish the two groups of anomalous years: Years with low September SIC feature episodes that are consistently stronger and more persistent than years with high SIC.

A Meteoric Water Budget for the Arctic Ocean

NASA Astrophysics Data System (ADS)

Alkire, Matthew B.; Morison, James; Schweiger, Axel; Zhang, Jinlun; Steele, Michael; Peralta-Ferriz, Cecilia; Dickinson, Suzanne

2017-12-01

A budget of meteoric water (MW = river runoff, net precipitation minus evaporation, and glacial meltwater) over four regions of the Arctic Ocean is constructed using a simple box model, regional precipitation-evaporation estimates from reanalysis data sets, and estimates of import and export fluxes derived from the literature with a focus on the 2003-2008 period. The budget indicates an approximate/slightly positive balance between MW imports and exports (i.e., no change in storage); thus, the observed total freshwater increase observed during this time period likely resulted primarily from changes in non-MW freshwater components (i.e., increases in sea ice melt or Pacific water and/or a decrease in ice export). Further, our analysis indicates that the MW increase observed in the Canada Basin resulted from a spatial redistribution of MW over the Arctic Ocean. Mean residence times for MW were estimated for the Western Arctic (5-7 years), Eastern Arctic (3-4 years), and Lincoln Sea (1-2 years). The MW content over the Siberian shelves was estimated (˜14,000 km3) based on a residence time of 3.5 years. The MW content over the entire Arctic Ocean was estimated to be ≥44,000 km3. The MW export through Fram Strait consisted mostly of water from the Eastern Arctic (3,237 ± 1,370 km3 yr-1) whereas the export through the Canadian Archipelago was nearly equally derived from both the Western Arctic (1,182 ± 534 km3 yr-1) and Lincoln Sea (972 ± 391 km3 yr-1).

Acoustic detections of summer and winter whales at Arctic gateways in the Atlantic and Pacific Oceans

NASA Astrophysics Data System (ADS)

Stafford, K.; Laidre, K. L.; Moore, S. E.

2016-02-01

Changes in sea ice phenology have been profound in regions north of arctic gateways, where the seasonal open-water period has increased by 1.5-3 months over the past 30 years. This has resulted in changes to the Arctic ecosystem, including increased primary productivity, changing food web structure, and opening of new habitat. In the "new normal" Arctic, ice obligate species such as ice seals and polar bears may fare poorly under reduced sea ice while sub-arctic "summer" whales (fin and humpback) are poised to inhabit new seasonal ice-free habitats in the Arctic. We examined the spatial and seasonal occurrence of summer and "winter" (bowhead) whales from September through December by deploying hydrophones in three Arctic gateways: Bering, Davis and Fram Straits. Acoustic occurrence of the three species was compared with decadal-scale changes in seasonal sea ice. In all three Straits, fin whale acoustic detections extended from summer to late autumn. Humpback whales showed the same pattern in Bering and Davis Straits, singing into November and December, respectively. Bowhead whale detections generally began after the departure of the summer whales and continued through the winter. In all three straits, summer whales occurred in seasons and regions that used to be ice-covered. This is likely due to both increased available habitat from sea ice reductions and post-whaling population recoveries. At present, in the straits examined here, there is spatial, but not temporal, overlap between summer and winter whales. In a future with further seasonal sea ice reductions, however, increased competition for resources between sub-Arctic and Arctic species may arise to the detriment of winter whales.

Modelling the impacts of a dipole-like climatic state over the Arctic

NASA Astrophysics Data System (ADS)

Pasha Karami, Mehdi; de Vernal, Anne; Hu, Xianmin; Myers, Paul G.

2015-04-01

The Arctic dipole anomaly (ADA) features a pattern with opposite sea-level pressure anomalies over the Canadian Archipelago and the Barents Sea. Changes in the predominance of Arctic atmospheric circulation modes and the shift towards a dipole mode in the past decade played a role in the summer sea ice loss and sea ice-freshwater export from the Arctic to the North Atlantic. Reconstruction of sea ice cover variations during Holocene also suggests opposite anomalies in the Barents Sea versus either the western Arctic or the Fram Strait area similar to the ADA pattern. It is vital to study such physical processes that cause dramatic changes in the Arctic sea ice recalling the link between the ADA and the current climate change. Here we focus on the question of how a persistent ADA-like state affects the Arctic sea ice distribution and its outflow to the Atlantic Ocean. For this purpose, an eddy-permitting regional configuration of the NEMO coupled ocean/sea-ice model is used. The regional domain covers the Arctic Ocean and the Northern-Hemisphere Atlantic, with a horizontal resolution of 1/4 degree at the equator (ANHA4). For the present-day simulations, boundary conditions are obtained by taking the average over the years with a positive ADA and those with a negative ADA. In the Holocene scenario, global climate model data are used to force our regional model. To exclude the role of Bering Strait and the heat flux from the Pacific Ocean, we repeat the experiments with a closed Bering Strait since a nearly closed Bering configuration was possible for the Early Holocene. The model results are compared with the paleoclimate data from Arctic and subarctic seas.

Atmospheric moisture transport: the bridge between ocean evaporation and Arctic ice melting

NASA Astrophysics Data System (ADS)

Gimeno, L.; Vázquez, M.; Nieto, R.; Trigo, R. M.

2015-09-01

Changes in the atmospheric moisture transport have been proposed as a vehicle for interpreting some of the most significant changes in the Arctic region. The increasing moisture over the Arctic during the last decades is not strongly associated with the evaporation that takes place within the Arctic area itself, despite the fact that the sea ice cover is decreasing. Such an increment is consistent and is more dependent on the transport of moisture from the extratropical regions to the Arctic that has increased in recent decades and is expected to increase within a warming climate. This increase could be due either to changes in circulation patterns which have altered the moisture sources, or to changes in the intensity of the moisture sources because of enhanced evaporation, or a combination of these two mechanisms. In this short communication we focus on the more objective assessment of the strong link between ocean evaporation trends and Arctic Sea ice melting. We will critically analyse several recent results suggesting links between moisture transport and the extent of sea ice in the Arctic, this being one of the most distinct indicators of continuous climate change both in the Arctic and on a global scale. To do this we will use a sophisticated Lagrangian approach to develop a more robust framework on some of these previous disconnecting results, using new information and insights. Results reached in this study stress the connection between two climate change indicators, namely an increase in evaporation over source regions (mainly the Mediterranean Sea, the North Atlantic Ocean and the North Pacific Ocean in the paths of the global western boundary currents and their extensions) and Arctic ice melting precursors.

Freshwater and its role in the Arctic Marine System: Sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans

NASA Astrophysics Data System (ADS)

Carmack, E. C.; Yamamoto-Kawai, M.; Haine, T. W. N.; Bacon, S.; Bluhm, B. A.; Lique, C.; Melling, H.; Polyakov, I. V.; Straneo, F.; Timmermans, M.-L.; Williams, W. J.

2016-03-01

The Arctic Ocean is a fundamental node in the global hydrological cycle and the ocean's thermohaline circulation. We here assess the system's key functions and processes: (1) the delivery of fresh and low-salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle, and Pacific Ocean inflows; (2) the disposition (e.g., sources, pathways, and storage) of freshwater components within the Arctic Ocean; and (3) the release and export of freshwater components into the bordering convective domains of the North Atlantic. We then examine physical, chemical, or biological processes which are influenced or constrained by the local quantities and geochemical qualities of freshwater; these include stratification and vertical mixing, ocean heat flux, nutrient supply, primary production, ocean acidification, and biogeochemical cycling. Internal to the Arctic the joint effects of sea ice decline and hydrological cycle intensification have strengthened coupling between the ocean and the atmosphere (e.g., wind and ice drift stresses, solar radiation, and heat and moisture exchange), the bordering drainage basins (e.g., river discharge, sediment transport, and erosion), and terrestrial ecosystems (e.g., Arctic greening, dissolved and particulate carbon loading, and altered phenology of biotic components). External to the Arctic freshwater export acts as both a constraint to and a necessary ingredient for deep convection in the bordering subarctic gyres and thus affects the global thermohaline circulation. Geochemical fingerprints attained within the Arctic Ocean are likewise exported into the neighboring subarctic systems and beyond. Finally, we discuss observed and modeled functions and changes in this system on seasonal, annual, and decadal time scales and discuss mechanisms that link the marine system to atmospheric, terrestrial, and cryospheric systems.

Late Cretaceous seasonal ocean variability from the Arctic.

PubMed

Davies, Andrew; Kemp, Alan E S; Pike, Jennifer

2009-07-09

The modern Arctic Ocean is regarded as a barometer of global change and amplifier of global warming and therefore records of past Arctic change are critical for palaeoclimate reconstruction. Little is known of the state of the Arctic Ocean in the greenhouse period of the Late Cretaceous epoch (65-99 million years ago), yet records from such times may yield important clues to Arctic Ocean behaviour in near-future warmer climates. Here we present a seasonally resolved Cretaceous sedimentary record from the Alpha ridge of the Arctic Ocean. This palaeo-sediment trap provides new insight into the workings of the Cretaceous marine biological carbon pump. Seasonal primary production was dominated by diatom algae but was not related to upwelling as was previously hypothesized. Rather, production occurred within a stratified water column, involving specially adapted species in blooms resembling those of the modern North Pacific subtropical gyre, or those indicated for the Mediterranean sapropels. With increased CO(2) levels and warming currently driving increased stratification in the global ocean, this style of production that is adapted to stratification may become more widespread. Our evidence for seasonal diatom production and flux testify to an ice-free summer, but thin accumulations of terrigenous sediment within the diatom ooze are consistent with the presence of intermittent sea ice in the winter, supporting a wide body of evidence for low temperatures in the Late Cretaceous Arctic Ocean, rather than recent suggestions of a 15 degrees C mean annual temperature at this time.

Sea Ice Patterns

NASA Image and Video Library

2017-12-08

On July 20, the U.S. Coast Guard Cutter Healy steamed south in the Arctic Ocean toward the edge of the sea ice. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is NASA's two-year shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research takes place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen For updates on the five-week ICESCAPE voyage, visit the mission blog at: go.usa.gov/WwU NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Arctic Sea Ice

NASA Image and Video Library

2017-12-08

On July 12, 2011, crew from the U.S. Coast Guard Cutter Healy retrieved a canister dropped by parachute from a C-130, which brought supplies for some mid-mission fixes. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is NASA's two-year shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research takes place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen For updates on the five-week ICESCAPE voyage, visit the mission blog at: go.usa.gov/WwU NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Changes in summer sea ice, albedo, and portioning of surface solar radiation in the Pacific sector of Arctic Ocean during 1982-2009

NASA Astrophysics Data System (ADS)

Lei, Ruibo; Tian-Kunze, Xiangshan; Leppäranta, Matti; Wang, Jia; Kaleschke, Lars; Zhang, Zhanhai

2016-08-01

SSM/I sea ice concentration and CLARA black-sky composite albedo were used to estimate sea ice albedo in the region 70°N-82°N, 130°W-180°W. The long-term trends and seasonal evolutions of ice concentration, composite albedo, and ice albedo were then obtained. In July-August 1982-2009, the linear trend of the composite albedo and the ice albedo was -0.069 and -0.046 units per decade, respectively. During 1 June to 19 August, melting of sea ice resulted in an increase of solar heat input to the ice-ocean system by 282 MJ·m-2 from 1982 to 2009. However, because of the counter-balancing effects of the loss of sea ice area and the enhanced ice surface melting, the trend of solar heat input to the ice was insignificant. The summer evolution of ice albedo matched the ice surface melting and ponding well at basin scale. The ice albedo showed a large difference between the multiyear and first-year ice because the latter melted completely by the end of a melt season. At the SHEBA geolocations, a distinct change in the ice albedo has occurred since 2007, because most of the multiyear ice has been replaced by first-year ice. A positive polarity in the Arctic Dipole Anomaly could be partly responsible for the rapid loss of summer ice within the study region in the recent years by bringing warmer air masses from the south and advecting more ice toward the north. Both these effects would enhance ice-albedo feedback.

Advection in polar and sub-polar environments: Impacts on high latitude marine ecosystems

NASA Astrophysics Data System (ADS)

Hunt, George L.; Drinkwater, Kenneth F.; Arrigo, Kevin; Berge, Jørgen; Daly, Kendra L.; Danielson, Seth; Daase, Malin; Hop, Haakon; Isla, Enrique; Karnovsky, Nina; Laidre, Kristin; Mueter, Franz J.; Murphy, Eugene J.; Renaud, Paul E.; Smith, Walker O.; Trathan, Philip; Turner, John; Wolf-Gladrow, Dieter

2016-12-01

We compare and contrast the ecological impacts of atmospheric and oceanic circulation patterns on polar and sub-polar marine ecosystems. Circulation patterns differ strikingly between the north and south. Meridional circulation in the north provides connections between the sub-Arctic and Arctic despite the presence of encircling continental landmasses, whereas annular circulation patterns in the south tend to isolate Antarctic surface waters from those in the north. These differences influence fundamental aspects of the polar ecosystems from the amount, thickness and duration of sea ice, to the types of organisms, and the ecology of zooplankton, fish, seabirds and marine mammals. Meridional flows in both the North Pacific and the North Atlantic oceans transport heat, nutrients, and plankton northward into the Chukchi Sea, the Barents Sea, and the seas off the west coast of Greenland. In the North Atlantic, the advected heat warms the waters of the southern Barents Sea and, with advected nutrients and plankton, supports immense biomasses of fish, seabirds and marine mammals. On the Pacific side of the Arctic, cold waters flowing northward across the northern Bering and Chukchi seas during winter and spring limit the ability of boreal fish species to take advantage of high seasonal production there. Southward flow of cold Arctic waters into sub-Arctic regions of the North Atlantic occurs mainly through Fram Strait with less through the Barents Sea and the Canadian Archipelago. In the Pacific, the transport of Arctic waters and plankton southward through Bering Strait is minimal. In the Southern Ocean, the Antarctic Circumpolar Current and its associated fronts are barriers to the southward dispersal of plankton and pelagic fishes from sub-Antarctic waters, with the consequent evolution of Antarctic zooplankton and fish species largely occurring in isolation from those to the north. The Antarctic Circumpolar Current also disperses biota throughout the Southern Ocean, and as a result, the biota tends to be similar within a given broad latitudinal band. South of the Southern Boundary of the ACC, there is a large-scale divergence that brings nutrient-rich water to the surface. This divergence, along with more localized upwelling regions and deep vertical convection in winter, generates elevated nutrient levels throughout the Antarctic at the end of austral winter. However, such elevated nutrient levels do not support elevated phytoplankton productivity through the entire Southern Ocean, as iron concentrations are rapidly removed to limiting levels by spring blooms in deep waters. However, coastal regions, with the upward mixing of iron, maintain greatly enhanced rates of production, especially in coastal polynyas. In these coastal areas, elevated primary production supports large biomasses of zooplankton, fish, seabirds, and mammals. As climate warming affects these advective processes and their heat content, there will likely be major changes in the distribution and abundance of polar biota, in particular the biota dependent on sea ice.

Squaring the Arctic Circle: connecting Arctic knowledge with societal needs

NASA Astrophysics Data System (ADS)

Wilkinson, J.

2017-12-01

Over the coming years the landscape of the Arctic will change substantially- environmentally, politically, and economically. Furthermore, Arctic change has the potential to significantly impact Arctic and non-Arctic countries alike. Thus, our science is in-demand by local communities, politicians, industry leaders and the public. During these times of transition it is essential that the links between science and society be strengthened further. Strong links between science and society is exactly what is needed for the development of better decision-making tools to support sustainable development, enable adaptation to climate change, provide the information necessary for improved management of assets and operations in the Arctic region, and and to inform scientific, economic, environmental and societal policies. By doing so tangible benefits will flow to Arctic societies, as well as for non-Arctic countries that will be significantly affected by climate change. Past experience has shown that the engagement with a broad range of stakeholders is not always an easy process. Consequently, we need to improve collaborative opportunities between scientists, indigenous/local communities, private sector, policy makers, NGOs, and other relevant stakeholders. The development of best practices in this area must build on the collective experiences of successful cross-sectorial programmes. Within this session we present some of the outreach work we have performed within the EU programme ICE-ARC, from community meetings in NW Greenland through to sessions at the United Nations Framework Convention on Climate Change COP Conferences, industry round tables, and an Arctic side event at the World Economic Forum in Davos.

Bryophytes from Simeonof Island in the Shumagin Islands, southwestern Alaska

USGS Publications Warehouse

Schofield, W.B.; Talbot, S. S.; Talbot, S.L.

2004-01-01

Simeonof Island is located south of the Alaska Peninsula in the hyperoceanic sector of the middle boreal subzone. We examined the bryoflora of Simeonof Island to determine species composition in an area where no previous collections had been reported. This field study was conducted in sites selected to represent the spectrum of environmental variation within Simeonof Island. Data were analyzed using published reports to compare bryophyte distribution patterns at three levels, the Northern Hemisphere, North America, and Alaska. A total of 271 bryophytes were identified: 202 mosses and 69 liverworts. The annotated list of species for Simeonof Island expands the known range for many species and fills distribution gaps within Hulte??n's Western Pacific Coast district. Maps and notes on the distribution of 14 significant distribution records are presented. Compared with bryophyte distribution in the Northern Hemisphere, the bryoflora of Simeonof Island primarily includes taxa of boreal (55%), temperate (20%), arctic (10%), and cosmopolitan (8%) distribution; 6% of the moss flora are western North America endemics. A description of the bryophytes present in the vegetation and habitat types is provided as is a quantitative analysis of the most frequently occurring bryophytes in crowberry heath.

Holocene Ostracoda from the Herald Canyon, Eastern Siberian Sea from the SWERUS-C3 Expedition 2014

NASA Astrophysics Data System (ADS)

Gemery, L.; Cronin, T. M.; Jakobsson, M.; Barrientos, N.; O'Regan, M.; Muschitiello, F.; Koshurnikov, A.; Gukov, A.

2015-12-01

We analyzed Arctic benthic ostracode assemblages from two piston cores (PC) and their complementary multicores from Herald Canyon in the Eastern Siberian Sea. The cores (SWERUS-L2-2-PC1 [8.1 m], 2-MUC4, 71.7 m water depth, and SWERUS-L2-4-PC1 [6.2 m], 4-MUC4, 119.7 m water depth) were collected during Leg 2 of the 2014 SWERUS-C3 Expedition. Radiocarbon dates on mollusks indicate that sediments from 2-PC1 and 4-PC1 were deposited over the last 5,000 and 10,000 years respectively. The dominant ostracode species include: Acanthocythereis dunelmensis, Cytheropteron elaeni, Elofsonella concinna, Kotoracythere janae, Normanicythere leioderma, Semicytherura complanata. Based on species' distributions obtained from a 1,200-sample modern ostracode database, these species are known to be typical of shallow mid- to outer-continental shelf environments in the modern Arctic Ocean. The abundant and diverse benthic ostracode assemblages found in these cores suggest the influence of nutrient-rich Pacific water flowing in through the Bering Strait. The faunal assemblages are fairly uniform throughout 2-PC1, suggesting minimal variability in Pacific water inflow since at least 5 ka. In the lower section of 4-PC1, there is a major change to ostracode assemblages containing typical inner shelf, often brackish-water species, such as Cytheromorpha macchesneyi, and associated shallow Arctic shelf species (Sarsicytheridea punctillata and several Cytheropteron species), reflecting a period of lower, deglacial sea level.

Oceanographic structure drives the assembly processes of microbial eukaryotic communities.

PubMed

Monier, Adam; Comte, Jérôme; Babin, Marcel; Forest, Alexandre; Matsuoka, Atsushi; Lovejoy, Connie

2015-03-17

Arctic Ocean microbial eukaryote phytoplankton form subsurface chlorophyll maximum (SCM), where much of the annual summer production occurs. This SCM is particularly persistent in the Western Arctic Ocean, which is strongly salinity stratified. The recent loss of multiyear sea ice and increased particulate-rich river discharge in the Arctic Ocean results in a greater volume of fresher water that may displace nutrient-rich saltier waters to deeper depths and decrease light penetration in areas affected by river discharge. Here, we surveyed microbial eukaryotic assemblages in the surface waters, and within and below the SCM. In most samples, we detected the pronounced SCM that usually occurs at the interface of the upper mixed layer and Pacific Summer Water (PSW). Poorly developed SCM was seen under two conditions, one above PSW and associated with a downwelling eddy, and the second in a region influenced by the Mackenzie River plume. Four phylogenetically distinct communities were identified: surface, pronounced SCM, weak SCM and a deeper community just below the SCM. Distance-decay relationships and phylogenetic structure suggested distinct ecological processes operating within these communities. In the pronounced SCM, picophytoplanktons were prevalent and community assembly was attributed to water mass history. In contrast, environmental filtering impacted the composition of the weak SCM communities, where heterotrophic Picozoa were more numerous. These results imply that displacement of Pacific waters to greater depth and increased terrigenous input may act as a control on SCM development and result in lower net summer primary production with a more heterotroph dominated eukaryotic microbial community.

A Review of Magnetic Anomaly Field Data for the Arctic Region: Geological Implications

NASA Technical Reports Server (NTRS)

Taylor, Patrick T.; vonFrese, Ralph; Roman, Daniel; Frawley, James J.

1999-01-01

Due to its inaccessibility and hostile physical environment remote sensing data, both airborne and satellite measurements, has been the main source of geopotential data over the entire Arctic region. Ubiquitous and significant external fields, however, hinder crustal magnetic field studies These potential field data have been used to derive tectonic models for the two major tectonic sectors of this region, the Amerasian and Eurasian Basins. The latter is dominated by the Nansen-Gakkel or Mid-Arctic Ocean Ridge and is relatively well known. The origin and nature of the Alpha and Mendeleev Ridges, Chukchi Borderland and Canada Basin of the former are less well known and a subject of controversy. The Lomonosov Ridge divides these large provinces. In this report we will present a summary of the Arctic geopotential anomaly data derived from various sources by various groups in North America and Europe and show how these data help us unravel the last remaining major puzzle of the global plate tectonic framework. While magnetic anomaly data represent the main focus of this study recently derived satellite gravity data are playing a major role in Arctic studies.

Spatial and vertical gradients in the stable carbon isotope composition of Lower Circumpolar Deep Water over the last 900 thousand years

NASA Astrophysics Data System (ADS)

Williams, T.; Hillenbrand, C. D.; Piotrowski, A. M.; Smith, J.; Hodell, D. A.; Frederichs, T.; Allen, C. S.

2014-12-01

Changes in stable carbon isotopes (δ13C) recorded in benthic foraminiferal calcite reflect that of the dissolved inorganic carbon (DIC) of ambient seawater, and thus are used to reconstruct past changes in water mass mixing. Records of benthic foraminiferal δ13C from the Atlantic Ocean have revealed the development of a sharp vertical δ13C gradient between 2300-2500m water depth during successive glacial periods throughout the Late Quaternary, with extremely negative δ13C values recorded below this depth. It had been hypothesised that this gradient resulted from an increased stratification of water masses within the glacial Atlantic Ocean, and that these extreme δ13C values originated in the Southern Ocean. However the mechanisms behind the formation of this gradient and extreme δ13C depletion have remained unclear. This is in part due to the poor preservation of calcareous microfossils in the corrosive waters below 2500-3000m found in the Southern Ocean, which hampers our understanding of this key region. Here we present a unique new δ13C deep water record measured on benthic foraminifera (Cibicidoides spp.) from a sediment core recovered from 2100m water depth in the Amundsen Sea, south-eastern Pacific sector of the Southern Ocean. The site is bathed in Lower Circumpolar Deep Water (LCDW) today, and combined palaeomagnetic and oxygen isotope stratigraphy show that the sediments continuously span at least the last 890 ka. A comparison of this new δ13C data with other LCDW records from ODP Sites 1089/1090 in the South Atlantic and ODP Site 1123 in the Southwest Pacific demonstrate a clear spatial gradient in circum-Antarctic LCDW during glacial periods. The pool of extremely depleted glacial deep marine δ13C is restricted to the Atlantic Sector of the Southern Ocean, with increasingly positive δ13C values found in the Southwest Pacific and the south-eastern Pacific sector of the Southern Ocean. This implies that the δ13C depletion in the deep glacial Atlantic was sourced in the Atlantic sector of the Southern Ocean, and remained limited to this sector. This finding indicates either increased supply of relatively more positive δ13C deep waters or increased vertical mixing in the Indian and Pacific sectors of the glacial Southern Ocean.

Predictable climate dynamics of abnormal East Asian winter monsoon: once-in-a-century snowstorms in 2007/2008 winter

NASA Astrophysics Data System (ADS)

Wu, Zhiwei; Li, Jianping; Jiang, Zhihong; He, Jinhai

2011-10-01

In 2008 (January-February), East Asia (EA) experiences the most severe and long-persisting snowstorm in the past 100 years. Results in this study show that 2007/2008 winter is dominant by the third principal mode of the East Asian winter monsoon (EAWM) which explains 8.7% of the total surface air temperature variance over EA. Significantly distinguished from the first two leading modes, the third mode positive phase features an increased surface pressure over the northwestern EA, an enhanced central Siberian high (CSH), a strengthened and northwestward extended western Pacific subtropical high (WPSH) and anomalously strong moisture transport from western Pacific, Arabian Sea and Bay of Bengal to EA. It also exhibits an intimate linkage with the sea surface temperature anomalies (SSTAs) in the Arctic Ocean areas adjacent to northern Eurasian continent, central North Pacific and northeastern Pacific. Such SSTAs emerge in prior autumn and persist through ensuing winter, signifying precursory conditions for the anomalous third EAWM mode. Numerical experiments with a simple general circulation model demonstrate that the Arctic SSTAs excite geo-potential height anomalies over northern Eurasian continent and impacts on the CSH, while the extra-tropical Pacific SSTAs deform the WPSH. Co-effects of them play crucial roles on origins of the third EAWM mode. Based on these results, an empirical model is established to predict the third mode of the EAWM. Hindcast is performed for the 1957-2008 period, which shows a quite realistic prediction skill in general and good prediction ability in the extreme phase of the third mode of the EAWM such as 2007/2008 winter. Since all these predictors can be readily monitored in real time, this empirical model provides a real time forecast tool and may facilitate the seasonal prediction of high-impact weather associated with the abnormal EAWM.

Moisture sources and pathways associated with the spatial variability of seasonal extreme precipitation over Canada

NASA Astrophysics Data System (ADS)

Tan, Xuezhi; Gan, Thian Yew; Chen, Yongqin David

2018-01-01

Nine regions with spatially coherent seasonal 3-day total precipitation extremes across Canada were identified using a clustering method that is compliant to the extreme value theory. Using storm back-trajectory analyses, we then identified possible moisture sources and pathways that are conducive to occurrences of seasonal extreme precipitation events in four seasons for the nine regions identified. Moisture pathways for all extreme precipitation events were clustered to nine dominant moisture pathway patterns using the self-organizing map method. Results show that horizontal moisture pathway patterns and their occurrences were not evidently different between seasons. However, warm (summer and fall) and cold (winter and spring) seasons show considerable differences in the spreading of moisture sources in all nine regions, even though many sources do not frequently contribute to extreme precipitation events. In all four seasons, terrestrial evapotranspiration had provided major moisture sources to many extreme precipitation events occurred in inland regions. Central Canada had received more widespread moisture sources over surrounding oceans of North America than western and eastern Canada, because of more diverse moisture pathway patterns for central Canada that transport moisture from all surrounding oceans to central Canada. Extreme precipitation in southwestern Canada mainly resulted from atmospheric rivers over the North Pacific Ocean. For northwestern Canada, moisture pathway patterns were from the northern Pacific, Arctic and northern Atlantic oceans, even though more than 78% of trajectories for northwestern Canada were from the North Pacific. Westerlies from the North Pacific Ocean and northern polar jet streams controlled dominant pathways to central and eastern Canada. More extreme precipitation events over Canada were fed by the Arctic Ocean in warm than in cold seasons.

Moisture sources and pathways associated with the spatial variability of seasonal extreme precipitation over Canada

NASA Astrophysics Data System (ADS)

Gan, T. Y. Y.; Tan, X.; Chen, Y. D.

2017-12-01

Nine regions with spatially coherent seasonal 3-day total precipitation extremes across Canada were identified using a clustering method that is compliant to the extreme value theory. Using storm back-trajectory analyses, we then identified possible moisture sources and pathways that are conducive to occurrences of seasonal extreme precipitation events in four seasons for the nine regions identified.Moisture pathways for all extreme precipitation events were clustered to nine dominant moisture pathway patterns using the self-organizing map method. Results show that horizontal moisture pathway patterns and their occurrences were not evidently different between seasons. However, warm (summer and fall) and cold (winter and spring) seasons show considerable differences in the spreading ofmoisture sources in all nine regions, even though many sources do not frequently contribute to extreme precipitation events. In all four seasons, terrestrial evapotranspiration had provided major moisture sources to many extreme precipitation events occurred in inland regions. Central Canada had received more widespread moisture sources over surrounding oceans of North America than western and eastern Canada, because of more diverse moisture pathway patterns for central Canada that transport moisture from all surrounding oceans to central Canada. Extreme precipitation in southwestern Canada mainly resulted from atmospheric rivers over the North Pacific Ocean. For northwestern Canada, moisture pathway patterns were from the northern Pacific, Arctic and northern Atlantic oceans, even though more than 78% of trajectories for northwestern Canada were from the North Pacific. Westerlies from the North Pacific Ocean and northern polar jet streams controlled dominant pathways to central and eastern Canada. More extreme precipitation events over Canada were fed by the Arctic Ocean in warm than in cold seasons.

Increasing frequency and duration of Arctic winter warming events

NASA Astrophysics Data System (ADS)

Graham, R. M.; Cohen, L.; Petty, A.; Boisvert, L.; Rinke, A.; Hudson, S. R.; Nicolaus, M.; Granskog, M. A.

2017-12-01

Record low Arctic sea ice extents were observed during the last three winter seasons (March). During each of these winters, near-surface air temperatures close to 0°C were observed, in situ, over sea ice in the central Arctic. Recent media reports and scientific studies suggest that such winter warming events were unprecedented for the Arctic. Here we use in situ winter (December-March) temperature observations, such as those from Soviet North Pole drifting stations and ocean buoys, to determine how common Arctic winter warming events are. The earliest record we find of a winter warming event was in March 1896, where a temperature of -3.7˚C was observed at 84˚N during the Fram expedition. Observations of winter warming events exist over most of the Arctic Basin. Despite a limited observational network, temperatures exceeding -5°C were measured in situ during more than 30% of winters from 1954 to 2010, by either North Pole drifting stations or ocean buoys. Correlation coefficients between the atmospheric reanalysis, ERA-Interim, and these in-situ temperature records are shown to be on the order of 0.90. This suggests that ERA-Interim is a suitable tool for studying Arctic winter warming events. Using the ERA-Interim record (1979-2016), we show that the North Pole (NP) region typically experiences 10 warming events (T2m > -10°C) per winter, compared with only five in the Pacific Central Arctic (PCA). We find a positive trend in the overall duration of winter warming events for both the NP region (4.25 days/decade) and PCA (1.16 days/decade), due to an increased number of events of longer duration.

The late Wisconsinan and Holocene record of Walrus (Odobenus rosmarus) from North America: A review with new data from Arctic and Atlantic Canada

USGS Publications Warehouse

Dyke, A.S.; Hooper, J.; Harington, C.R.; Savelle, J.M.

1999-01-01

The Late Wisconsinan and Holocene record of the Atlantic walrus is known from numerous collections of bones and tusks from Arctic Canada and south to North Carolina, as well as from many archaeological sites in the Arctic and Subarctic. In contrast, the Pacific walrus has no dated Late Wisconsinan or early Holocene record in North America, and it may have been displaced into the northwest Pacific at Last Glacial Maximum (LGM). The Atlantic walrus rapidly exploited newly deglaciated territory, moving northward from its LGM refugium and reaching the Bay of Fundy by 12800 B.P., the Grand Banks by 12500 B.P., southern Labrador by 11500 B.P., and the central Canadian Arctic Archipelago (CAA) by 9700 B.P. Its southern range limit may have retracted to the Bay of Fundy by ca. 7500 B.P. Within the CAA, walrus remains cluster in two main age groups: 9700 to 8500 B.P. and 5000 to 4/3000 B.P. This pattern strongly resembles the distribution of bowhead whale radiocarbon ages from the same area, which suggests a common control by sea-ice conditions. Walrus remains occur in Indian culture archaeological sites as old as 7500 B.P. and, in some cases (Namu, British Columbia, and Mackinac Island, Michigan), they evidently represent long-distance human transport. They are much more common in Paleoeskimo and Neoeskimo culture sites. However, they occur in very low abundances, and generally as debitage, in sites older than Dorset (2500 B.P.). The walrus, therefore, may not have been hunted by early Paleoeskimos. Beginning with Early Dorset, walrus remains occur in definite diet-related contexts. Middle Dorset (2300 to 1500 B.P.) and late Thule (<400 B.P.) sites are missing from the High Arctic, and there may be a similar gap in the middle Pre-Dorset (3400 to 2600 B.P.). Sea-ice conditions at these times may have adversely affected availability of walrus and other marine mammal resources. Walrus is a prominent faunal element in Middle Dorset sites on the Labrador coast; this is consistent with a southward displacement of people and resources.

76 FR 13331 - Fisheries of the Exclusive Economic Zone Off Alaska; Revisions to Pacific Cod Fishing in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-11

... Department of Fish and Game (ADF&G) through emergency order under the authority of State regulations at 5 AAC... Pacific cod among ten fishery sectors created in Amendment 67, to better reflect the historical dependency...

Arctic Black Carbon Initiative: Reducing Emissions of Black Carbon from Power & Industry in Russia

NASA Astrophysics Data System (ADS)

Cresko, J.; Hodson, E. L.; Cheng, M.; Fu, J. S.; Huang, K.; Storey, J.

2012-12-01

Deposition of black carbon (BC) on snow and ice is widely considered to have a climate warming effect by reducing the surface albedo and promoting snowmelt. Such positive climate feedbacks in the Arctic are especially problematic because rising surface temperatures may trigger the release of large Arctic stores of terrestrial carbon, further amplifying current warming trends. Recognizing the Arctic as a vulnerable region, the U.S. government committed funds in Copenhagen in 2009 for international cooperation targeting Arctic BC emissions reductions. As a result, the U.S. Department of State has funded three research and demonstration projects with the goal to better understand and mitigate BC deposition in the Russian Arctic from a range of sources. The U.S. Department of Energy's (DOE) Arctic BC initiative presented here is focused on mitigating BC emissions resulting from heat and power generation as well as industrial applications. A detailed understanding of BC sources and its transport and fate is required to prioritize efforts to reduce BC emissions from sources that deposit in the Russian Arctic. Sources of BC include the combustion of fossil fuels (e.g. coal, fuel oil, diesel) and the combustion of biomass (e.g. wildfires, agricultural burning, residential heating and cooking). Information on fuel use and associated emissions from the industrial and heat & power sectors in Russia is scarce and difficult to obtain from the open literature. Hence, our project includes a research component designed to locate Arctic BC emissions sources in Russia and determine associated BC transport patterns. We use results from the research phase to inform a subsequent assessment/demonstration phase. We use a back-trajectory modeling method (potential source contribution function - PSCF), which combines multi-year, high-frequency measurements with knowledge about atmospheric transport patterns. The PSCF modeling allows us to map the probability (by season and year) at course resolution (2.5° x 2.5° spatial resolution) that a particular region emits BC which deposits in the Russian Arctic. We utilize data from three Arctic measurement stations during the most recent decade: Alert, Northwest Territories, Canada; Barrow, Alaska; and Tiksi Bay, Russia. To understand more about individual Arctic BC sources, we conduct further research to improve inventory estimates of Russian industrial and energy sector BC emissions. By comparing inventory data on power plant locations and emissions from two publically-available databases (EDGAR-HTAP and CARMA databases) to each other and to additional observations from satellites and the AERONET observation network in Russia, we assess the accuracy of the Russian BC emission inventory in EDGAR-HTAP, a commonly used database for atmospheric transport modeling. We then use a global (GEOS-CHEM) atmospheric transport model to quantify the finer spatial distribution of BC within the Arctic. Lastly, we use data on Russian fuel use combined with published emissions factors to build a national-scale model of energy use and associated emissions from critical industrial and heat & power sources of BC. We use this model to estimate the technical potential of reducing BC emissions through proven mitigation efforts such as improvements in energy efficiency and in emission control technologies.

Atmospheric Mercury Transport and Chemistry in Western Canada and the Arctic: Results from the IPY Project INCATPA

NASA Astrophysics Data System (ADS)

Cole, A. S.; Steffen, A.; Hung, H.

2010-12-01

Elevated levels of mercury and other pollutants are an ongoing threat to the health of Arctic people and wildlife, despite the vast distance that separates the region from major anthropogenic sources of these contaminants. The International Polar Year (IPY) project INterContinental Atmospheric Transport of anthropogenic Pollutants to the Arctic (INCATPA) is investigating the transport of pollutants, specifically persistent organic pollutants and mercury, from source regions to the remote Arctic. Transport from Asia is of particular interest since Asian sources comprise a significant and increasing fraction of global mercury emissions. The INCATPA project is also studying how climate change may affect atmospheric chemistry and transport of these pollutants in the Arctic. Mercury studies under INCATPA have involved concurrent measurements of ambient mercury during the period 2007-2009 at new and ongoing sites in Arctic and Pan-Pacific regions. These data include a first look at ambient mercury levels in areas of western Canada where mercury had not previously been monitored. At some sites, mercury measurements were analyzed along with supplementary data to assess contributions from local and long-distance sources. Long-term Arctic monitoring data were also used to address how climate change may already be affecting mercury chemistry and deposition in this region. As IPY and the INCATPA project wind down, their legacy is a continuation of mercury monitoring at these sites and new international scientific relationships to support growing international cooperation on the delivery of sound science for the development of public policy on mercury.

Local and large-scale atmospheric responses to reduced Arctic sea ice and ocean warming in the WRF model

NASA Astrophysics Data System (ADS)

Porter, David F.; Cassano, John J.; Serreze, Mark C.

2012-06-01

The Weather Research and Forecasting (WRF) model is used to explore the sensitivity of the large-scale atmospheric energy and moisture budgets to prescribed changes in Arctic sea ice and sea surface temperatures (SSTs). Observed sea ice fractions and SSTs from 1996 and 2007, representing years of high and low sea ice extent, are used as lower boundary conditions. A pan-Arctic domain extending into the North Pacific and Atlantic Oceans is used. ERA-Interim reanalysis data from 1994 to 2008 are employed as initial and lateral forcing data for each high and low sea ice simulation. The addition of a third ensemble, with a mixed SST field between years 1996 and 2007 (using 2007 SSTs above 66°N and 1996 values below), results in a total of three 15-member ensembles. Results of the simulations show both local and remote responses to reduced sea ice. The local polar cap averaged response is largest in October and November, dominated by increased turbulent heat fluxes resulting in vertically deep heating and moistening of the Arctic atmosphere. This warmer and moister atmosphere is associated with an increase in cloud cover, affecting the surface and atmospheric energy budgets. There is an enhancement of the hydrologic cycle, with increased evaporation in areas of sea ice loss paired with increased precipitation. Most of the Arctic climate response results from within-Arctic changes, although some changes in the hydrologic cycle reflect circulation responses to midlatitude SST forcing, highlighting the general sensitivity of the Arctic climate.

Connecting Arctic Research Across Boundaries through the Arctic Research Consortium of the United States (ARCUS)

NASA Astrophysics Data System (ADS)

Rich, R. H.; Myers, B.; Wiggins, H. V.; Zolkos, J.

2017-12-01

The complexities inherent in Arctic research demand a unique focus on making connections across the boundaries of discipline, institution, sector, geography, knowledge system, and culture. Since 1988, ARCUS has been working to bridge these gaps through communication, coordination, and collaboration. Recently, we have worked with partners to create a synthesis of the Arctic system, to explore the connectivity across the Arctic research community and how to strengthen it, to enable the community to have an effective voice in research funding policy, to implement a system for Arctic research community knowledge management, to bridge between global Sea Ice Prediction Network researchers and the science needs of coastal Alaska communities through the Sea Ice for Walrus Outlook, to strengthen ties between Polar researchers and educators, and to provide essential intangible infrastructure that enables cost-effective and productive research across boundaries. Employing expertise in managing for collaboration and interdisciplinarity, ARCUS complements and enables the work of its members, who constitute the Arctic research community and its key stakeholders. As a member-driven organization, everything that ARCUS does is achieved through partnership, with strong volunteer leadership of each activity. Key organizational partners in the United States include the U.S. Arctic Research Commission, Interagency Arctic Research Policy Committee, National Academy of Sciences Polar Research Board, and the North Slope Science Initiative. Internationally, ARCUS maintains strong bilateral connections with similarly focused groups in each Arctic country (and those interested in the Arctic), as well as with multinational organizations including the International Arctic Science Committee, the Association of Polar Early Career Educators, the University of the Arctic, and the Arctic Institute of North America. Currently, ARCUS is applying the best practices of the science of team science, expanding awareness of Arctic research in Washington, DC and in Alaska, and working to expand the base of support for Arctic research during this time of challenged U.S. federal research funding. The presentation will highlight our latest work to promote synthesis and systems thinking and make valuable connections.

Effectively engaging the private sector through vouchers and contracting - A case for analysing health governance and context.

PubMed

Nachtnebel, Matthias; O'Mahony, Ashleigh; Pillai, Nandini; Hort, Kris

2015-11-01

Health systems of low and middle income countries in the Asia Pacific have been described as mixed, where public and private sector operate in parallel. Gaps in the provision of primary health care (PHC) services have been picked up by the private sector and led to its growth; as can an enabling regulatory environment. The question whether governments should purchase services from the private sector to address gaps in service provision has been fiercely debated. This purposive review draws evidence from systematic reviews, and additional published and grey literature, for input into a policy brief on purchasing PHC-services from the private sector for underserved areas in the Asia Pacific region. Additional published and grey literature on vouchers and contracting as mechanisms to engage the private sector was used to supplement the conclusions from systematic reviews. We analysed the literature through a policy lens, or alternatively, a 'bottom-up' approach which incorporates components of a realist review. Evidence indicates that both vouchers and contracting can improve health service outcomes in underserved areas. These outcomes however are strongly influenced by (1) contextual factors, such as roles and functions attributable to a shared set of key actors (2) the type of delivered services and community demand (3) design of the intervention, notably provider autonomy and trust (4) governance capacity and provision of stewardship. Examining the experience of vouchers and contracting to expand health services through engagement with private sector providers in the Asia Pacific found positive effects with regards to access and utilisation of health services, but more importantly, highlighted the significance of contextual factors, appropriate selection of mechanism for services provided, and governance arrangements and stewardship capacity. In fact, for governments seeking to engage the private sector, analysis of context and capacities are potentially a more useful frame than generalizable outcomes of effectiveness. Copyright © 2015 Elsevier Ltd. All rights reserved.

DNA barcoding unmasks overlooked diversity improving knowledge on the composition and origins of the Churchill algal flora.

PubMed

Saunders, Gary W; McDevit, Daniel C

2013-03-16

Sampling expeditions to Churchill in the Canadian subarctic were completed with the aim of compiling a molecular-assisted survey of the macroalgal flora (seaweeds) for comparison to published accounts for this area, which are based on morphological identifications. Further, because the Churchill region was covered by ice until recently (~10,000 before present), the current algal flora has had to migrate from adjacent waters into that region. We used our DNA barcode data to predict the relative contribution of the North Atlantic and North Pacific floras (Likely Source Region) in repopulating the Churchill region following the most recent glacial retreat. We processed 422 collections representing ~50 morpho-species, which is the approximate number reported for this region, and generated DNA barcode data for 346 of these. In contrast to the morpho-species count, we recovered 57 genetic groups indicating overlooked species (this despite failing to generate barcode data for six of the ~50 morpho-species). However, we additionally uncovered numerous inconsistencies between the species that are currently listed in the Churchill flora (again as a result of overlooked species diversity, but combined with taxonomic confusion) and those identified following our molecular analyses including eight new records and another 17 genetic complexes in need of further study. Based on a comparison of DNA barcode data from the Churchill flora to collections from the contiguous Atlantic and Pacific floras we estimate that minimally 21% (possibly as much as 44%) of the Churchill flora was established by migration from the Pacific region with the balance of species arriving from the Atlantic (predominantly North American populations) following the last glacial retreat. Owing to difficulties associated with the morphological identification of macroalgae, our results indicate that current comprehension of the Canadian Arctic flora is weak. We consider that morphology-based field-identifications are ill-advised in carrying out floristic and ecological surveys for macroalgae and that much of the current data, at least for the Canadian Arctic, should be used with caution. Our efforts to use DNA barcode data to identify the most Likely Source Regions for macroalgal species currently found in Churchill suggests that migration from both the Atlantic and the Pacific have played important roles in establishing the Canadian Arctic flora. This result has significance for understanding both the current and future biodiversity and biogeography of macroalgae in these waters.

Spatial Distributions of DDTs in the Water Masses of the Arctic Ocean.

PubMed

Carrizo, Daniel; Sobek, Anna; Salvadó, Joan A; Gustafsson, Örjan

2017-07-18

There is a scarcity of data on the amount and distribution of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) and its metabolites in intermediate and deep ocean water masses. Here, the distribution and inventories of DDTs in water of the Arctic shelf seas and the interior basin are presented. The occurrence of ∑ 6 DDT (0.10-66 pg L -1 ) in the surface water was dominated by 4,4'-DDE. In the Central Arctic Ocean increasing concentrations of DDE with depth were observed in the Makarov and Amundsen basins. The increasing concentrations down to 2500 m depth is in accordance with previous findings for PCBs and PBDEs. Similar concentrations of DDT and DDEs were found in the surface water, while the relative contribution of DDEs increased with depth, demonstrating a transformation over time and depth. Higher concentrations of DDTs were found in the European part of the Arctic Ocean; these distributions likely reflect a combination of different usage patterns, transport, and fate of these compounds. For instance, the elevated concentrations of DDTs in the Barents and Atlantic sectors of the Arctic Ocean indicate the northbound Atlantic current as a significant conveyor of DDTs. This study contributes to the very rare data on OCPs in the vast deep-water compartments and combined with surface water distribution across the Arctic Ocean helps to improve our understanding of the large-scale fate of DDTs in the Arctic.

Information And Data-Sharing Plan of IPY China Activity

NASA Astrophysics Data System (ADS)

Zhang, X.; Cheng, W.

2007-12-01

Polar Data-Sharing is an effective resolution to global system and polar science problems and to interdisciplinary and sustainable study, as well as an important means to deal with IPY scientific heritages and realize IPY goals. Corresponding to IPY Data-Sharing policies, Information and Data-Sharing Plan was listed in five sub-plans of IPY Chinese Programme launched in March, 2007,they are Scientific research program of the Prydz Bay, Amery Ice Shelf and Dome A transects(short title:'PANDA'), the Arctic Scientific Research Expedition Plan, International Cooperation Plan, Information and Data-Sharing Plan, Education and Outreach. China, since the foundation of Antarctic Zhongshan Station in 1989, has carried out systematic scientific expeditions and researches in Larsemann Hills, Prydz Bay and the neighbouring sea areas, organized 14 Prydz Bay oceanographic investigations, 3 Amery Ice Shelf expeditions, 4 Grove Mountains expeditions and 5 inland ice cap scientific expeditions. 2 comprehensive oceanographic investigations in the Arctic Ocean were conducted in 1999 and 2003, acquired a large amount of data and samples in PANDA section and fan areas of Pacific Ocean in the Arctic Ocean. A mechanism of basic data submitting ,sharing and archiving has been gradually set up since 2000. Presently, Polar Science Database and Polar Sample Resource Sharing Platform of China with the aim of sharing polar data and samples has been initially established and began to provide sharing service to domestic and oversea users. According to IPY Chinese Activity, 2 scientific expeditions in the Arctic Ocean, 3 in the South Ocean, 2 at Amery Ice Shelf, 1 on Grove Mountains and 2 inland ice cap expeditions on Dome A will be carried out during IPY period. According to the experiences accumulated in the past and the jobs in the future, the Information and Data- Sharing Plan, during 2007-2010, will save, archive, and provide exchange and sharing services upon the data obtained by scientific expeditions on the site of IPY Chinese Programme. Meanwhile, focusing on areas in east Antarctic Dome A-Grove Mountain-Zhongshan Station-Amery Ice Shelf-Prydz Bay Section and the fan areas of Pacific Ocean in the Arctic Ocean, the Plan will also collect and integrate IPY data and historical data and establish database of PANDA Section and the Arctic Ocean. The details are as follows: On the basis of integrating the observed data acquired during the expeditions of China, the Plan will, adopting portal technology, develop 5 subject databases (English version included):(1) Database of Zhongshan Station- Dome A inner land ice cap section;(2) Database of interaction of ocean-ice-atmosphere-ice shelf in east Antarctica;(3) Database of geological and glaciological advance and retreat evolvement in Grove Mountains; (4) Database of Solar Terrestrial Physics at Zhongshan Station; (5) Oceanographic database of fan area of Pacific Ocean in the Arctic Ocean. CN-NADC of PRIC is the institute which assumes the responsibility for the Plan, specifically, it coordinates and organizes the operation of the Plan which includes data management, developing the portal of data and information sharing, and international exchanges. The specific assignments under the Plan will be carried out by research institutes under CAS (Chinese Academy of Sciences), SOA ( State Oceanic Administration), State Bureau of Surveying and Mapping and Ministry of Education.

Seasonal Storminess in the North Pacific, Bering Sea, and Alaskan Regions

NASA Astrophysics Data System (ADS)

Shippee, N. J.; Atkinson, D. E.; Walsh, J. E.; Partain, J.; Gottschalck, J.; Marra, J.

2012-12-01

Annually, extra-tropical cyclones present a high impact natural hazard to the North Pacific, Bering Sea, and Alaskan regions. In these regions, extensive subsistence and commercial fishing, new oil and gas field development, tourism, growing interest in and exploitation of new commercial shipping potential, and increasing military and Coast Guard activity, all represent potential parties impacted by storms in these waters. It is of interest to many parties to begin developing capacity to provide some indication of storm activity at a monthly- to seasonal-outlook (30 to 90 days) timeframe. Using storm track data from NOAA's Climate Prediction Center for the North Pacific and Alaskan region, an experimental seasonal storminess outlook product, using eigen-based methods similar to the operational seasonal temperature and precipitation products currently produced at NOAA CPC, has been created and tested in hindcast mode using predicted states of ENSO, the Pacific Decadal Oscillation (PDO), the Pacific-North American Pattern (PNA), and the Arctic Oscillation (AO). A sample of the seasonal storminess outlook product will be shown along with a discussion of the utility of individual teleconnection patterns in the generation of the product.

The Potential for Soviet Penetration of the Pacific Islands: An Assessment,

DTIC Science & Technology

1984-12-01

economies also implies diseconornies of 0 scale in both the public and private sectors. Investments in econmic and social infrastructures such as...source) was less to be feared by the Pacific Islands under current circunstances than econmic dcmination (again, whatever the source). Econacnic

The challenges of marine spatial planning in the Arctic: Results from the ACCESS programme.

PubMed

Edwards, Rosemary; Evans, Alan

2017-12-01

Marine spatial planning is increasingly used to manage the demands on marine areas, both spatially and temporally, where several different users may compete for resources or space, to ensure that development is as sustainable as possible. Diminishing sea-ice coverage in the Arctic will allow for potential increases in economic exploitation, and failure to plan for cross-sectoral management could have negative economic and environmental results. During the ACCESS programme, a marine spatial planning tool was developed for the Arctic, enabling the integrated study of human activities related to hydrocarbon exploitation, shipping and fisheries, and the possible environmental impacts, within the context of the next 30 years of climate change. In addition to areas under national jurisdiction, the Arctic Ocean contains a large area of high seas. Resources and ecosystems extend across political boundaries. We use three examples to highlight the need for transboundary planning and governance to be developed at a regional level.

NASA Global Hawk: A New Tool for Earth Science Research

NASA Technical Reports Server (NTRS)

Hall, Phill

2009-01-01

This slide presentation reviews the Global Hawk, a unmanned aerial vehicle (UAV) that NASA plans to use for Earth Sciences research. The Global Hawk is the world's first fully autonomous high-altitude, long-endurance aircraft, and is capable of conducting long duration missions. Plans are being made for the use of the aircraft on missions in the Arctic, Pacific and Western Atlantic Oceans. There are slides showing the Global Hawk Operations Center (GHOC), Flight Control and Air Traffic Control Communications Architecture, and Payload Integration and Accommodations on the Global Hawk. The first science campaign, planned for a study of the Pacific Ocean, is reviewed.

Beyond the Continent: Creating an Independent Scientific Assessment Process for the Hawai`i and U.S. Affiliated Pacific Islands Region

NASA Astrophysics Data System (ADS)

Grecni, Z. N.; Keener, V. W.

2017-12-01

An external evaluation found that the inclusion of users of climate information and diverse regional experts in developing the 2012 Pacific Islands Regional Climate Assessment was a key factor in the report's perceived credibility and usefulness (Moser 2013). The 2012 assessment is seen as a foundational summary for Hawai`i and the U.S.-Affiliated Pacific Islands and is still used in vulnerability assessments and to support decisions by public- and private-sector actors. Recently, lessons learned from the 2012 assessment process were applied in engaging technical experts and potential future users in developing a chapter for the U.S. National Climate Assessment, as a regional update that builds on previous assessment activities. In the absence of downscaled climate projection scenarios and products available to the contiguous U.S., the Pacific Islands chapter continued to draw on projections from regional climate models and extensive user engagement. Through surveys, webinars, technical sectoral workshops, and peer review networks, the regional author team received input from a range of stakeholders. In particular, engagement aimed to identify key risks in sectors of importance to the Hawai`i and U.S.-Affiliated Pacific Islands region and cases in which stakeholder groups are already implementing measures toward resilience and adaptation. Data collection began during the chapter development process and will continue at the release of the 4th National Climate Assessment in 2018, with the aim of evaluating how stakeholder engagement affects the assessment's usefulness in assisting island communities to understand risks and vulnerabilities and review potential adaptation strategies.

Assessing the role of solar radiation in heating, photosynthesis, and photo-oxidation in upper Arctic Ocean waters via autonomous buoys

NASA Astrophysics Data System (ADS)

Hill, V. J.; Steele, M.; Light, B.

2016-02-01

As part of the Arctic Observing Network, a new ice-tethered buoy has been developed for monitoring the role of sunlight in regulating ocean temperature, phytoplankton growth, and carbon cycling. A 20 or 50 m string (depending on local bathymetry) supports sensors both within and below the ice for the hourly measurement of downwelling irradiance, temperature, Chlorophyll a, light backscattering, and dissolved organic material (DOM). Two buoys were deployed in March 2014 and two in March 2015. Because the buoys are engineered to survive melting out of first year ice, they have successfully provided complete seasonal records of water column warming, phytoplankton abundance and photo-oxidation patterns in the Pacific Arctic Region. The data collected will be used to determine whether reduced ice extent and thinner ice are driving increases in under ice warming, accelerating bottom ice ablation, increasing available photosynthetic radiation to support large under ice blooms, and to quantify photo-oxidation of the DOM pool. Observations so far have revealed strong under ice daily warming as high as ±0.5 °C driven by local solar radiation. Water column absorption was dominated by colored dissolved organic material which served to trap solar radiation in the upper water column. Chlorophyll concentrations observed in June and July indicated high phytoplankton abundance beneath the ice. Light intensity at this time was not sufficient to support growth rates high enough to produce the 8 to 10 mg m-3 of chlorophyll observed. We hypothesize that phytoplankton were advected under the ice from the ice edge. However, once there phytoplankton were able to sustain low growth rates leading to nutrient limitation before open water status was reached. Strong daily cycles of photo-oxidation have also been observed in the late summer that indicate the fast cycling of highly labile DOM in the open waters of the Pacific Arctic Region.

Determining bathymetric distributions of the eelgrass Zostera marina L. in three turbid estuaries of the eastern North Pacific coast

EPA Science Inventory

Improved methods for determining bathymetric distributions of dominant intertidal plants throughout their estuarine range are needed. Zostera marina is a seagrass native to estuaries of the northeastern Pacific and many other sectors of the world ocean. The technique described ...

Climate change in Asia and the Pacific: How can countries adapt?

USDA-ARS?s Scientific Manuscript database

The Asia Pacific (AP) region is more vulnerable to climate change risks than other regions, given its dependence on the natural resources and agricultural sector for economic development with densely populated coastal areas, weak institutions, and the poverty of a considerable proportion of its popu...

Was the Eocene Arctic a Source Area for Exotic Plants and Mammals? (Invited)

NASA Astrophysics Data System (ADS)

Eberle, J. J.; Harrington, G. J.; Fricke, H. C.; Humphrey, J.; Hackett, L.; Newbrey, M.; Hutchison, J. H.

2010-12-01

Today’s High Arctic is undergoing rapid warming, but the impact on its animal and plant communities is not clear. As a deep time analog to better understand and predict the impacts of global warming on the Arctic biota, early Eocene (52-53 Ma) rocks on Ellesmere Island, Nunavut in Canada’s High Arctic (~79°N latitude) preserve evidence of diverse terrestrial ecosystems that supported dense forests inhabited by turtles, alligators, snakes, primates, tapirs, brontotheres, and hippo-like Coryphodon. The fossil localities were just a few degrees further south and still well above the Arctic Circle during the early Eocene; consequently, the biota experienced months of continuous sunlight as well as darkness, the Arctic summer and winter, respectively. The flora and fauna of the early Eocene Arctic imply warmer, wetter conditions than at present, and recently published analyses of biogenic phosphate from fossil fish, turtle, and mammal estimate warm summers (19 - 20 C) and mild, above-freezing winters. In general, temperature estimates for the early Eocene Arctic can be compared to those found today in temperate rainforests in the Pacific Northwest of the United States. The early Eocene Arctic mammalian fauna shares most genera with coeval mid-latitude faunas thousands of kilometers to the south in the US Western Interior, and several genera also are shared with Europe and Asia. Recent analyses suggest that the large herbivores such as hippo-like Coryphodon were year-round inhabitants in the Eocene Arctic forests. Although several of the Eocene Arctic mammalian taxa are hypothesized to have originated in either mid-latitude North America or Asia, the earlier occurrence of certain clades (e.g., tapirs) in the Arctic raises the possibility of a northern high-latitude origin. Analysis of the early Eocene Arctic palynoflora indicates comparable richness to early Eocene plant communities in the US Western Interior, but nearly 50% of its species (mostly angiosperms) are not found in correlative strata of either mid-latitude North America or Europe. Either the Arctic region is a source of some evolutionary novelty, or alternatively it recruited plants directly from Asia. In sum, although the Arctic was undoubtedly en route for terrestrial plants and animals dispersing across Holarctic continents during parts of the Paleogene, evidence from both the Eocene plant and vertebrate communities on Ellesmere Island indicates the Arctic must also be evaluated as a potential source area for exotic taxa.

The Increase of the Ice-free Season as Further Indication of the Rapid Decline of the Arctic sea ice

NASA Astrophysics Data System (ADS)

Rodrigues, J.

2008-12-01

The unprecedented depletion of sea ice in large sectors of the Arctic Ocean in the summer of 2007 has been the subject of many publications which highlight the spectacular disappearance of the sea ice at the time of minimum ice cover or emphasise the losses at very high latitudes. However, minimum values can be strongly affected by specific circumstances occurring in a comparatively short time interval. The unusually clear skies and the presence of a particular wind pattern over the Arctic Ocean may partly explain the record minimum attained in September 2007. In this contribution, instead of limiting ourselves to the September minimum or the March maximum, we consider the ice conditions throughout the year, opting for a less used, and hopefully more convenient approach. We chose as variables to describe the evolution of the sea ice situation in the Arctic Ocean and peripheral seas in the 1979-2007 period the length of the ice- free season (LIFS) and the inverse sea ice index (ISII). The latter is a quantity that measures the degree of absence of sea ice in a year and varies between zero (when there is a perennial ice cover) and one (when there is open water all year round). We used sea ice concentration data obtained from passive microwave satellite imagery and processed with the Bootstrap algorithm for the SMMR and SSM/I periods, and with the Enhanced NASA Team algorithm for the AMSR-E period. From a linear fit of the observed data, we found that the average LIFS in the Arctic went from 118 days in the late 1970s to 148 days in 2006, which represents an average rate of increase of 1.1 days/year. In the period 2001-2007 the LIFS increased monotonically at an average rate of 5.5 days/year, in good agreement with the general consensus that the Arctic sea ice is currently in an accelerated decline. We also found that 2007 was the longest ice- free season on record (168 days). The ISII also reached a maximum in 2007 . We also investigated what happened at the regional level. For example, the Northwest Passage and the Northern Sea Route are especially relevant to assess the maritime transport between the Atlantic and the Pacific, changes in the ice cover in oil rich areas such as the north coast of Alaska will attract the attention of the oil industry, and the disappearance of the sea ice in Hudson Bay will strongly affect its wildlife. We divided the Arctic in 85 regions and examined how the LIFS and the ISII changed in each of them since 1979. 53 regions enjoyed their longest ice-free seasons in 2006 or 2007. 2006 was special for the Canadian Arctic (longest ice-free season on record for about half of the regions) while 2007 was the year of the Russian Arctic (with the longest ice-free season in the period under study for more than half of the regions). Some of the largest variations were observed in the Russian Arctic, where the average LIFS increased from 84 days in the late 1970s to 129 around 2006, to reach a maximum of 171 days in 2007. Let us quote the changes in the White Sea (105 days between 1979 and 2006), in the South Barents Sea (70 days), in the South East Siberian Sea (60 days) and in the mid-latitude Chukchi Sea (66 days). Other areas where important changes took place include the Gulf of Finland (101 days), the Gulf of Riga (111 days) and the West coast of Spitsbergen (61 days). In the Canadian Arctic it is worth mentioning the increase of 62 days in Hudson Strait, 36 days in Hudson and Baffin Bays, and 52 days in Davis St. In almost all straits and sounds of the High Canadian Arctic the increase has been clearly non-linear and we prefer to compare the average LIFS in the periods 1979-1983 and 2002-2006. We quote an increase of 87 days in Lancaster Sound and of 74 days in Coronation Gulf. class="ab'>

US Navy Operational Global Ocean and Arctic Ice Prediction Systems

DTIC Science & Technology

2014-09-01

meridional overturning circulation (Figure 29 in Hurlburt et al., 2011), when comparing a non-assimilative simulation with a data assimilative...boundary current regions of the Gulf Stream ( Atlantic ), the Kuroshio (Pacific), and the Agulhas and Somali Currents (both Indian). Consequently...Oceanic and Atmospheric Administration at the National Centers for Environmental Prediction (NCEP), initially for the North Atlantic (Mehra and

Size distribution of absorbing and fluorescing DOM in Beaufort Sea, Canada Basin

NASA Astrophysics Data System (ADS)

Gao, Zhiyuan; Guéguen, Céline

2017-03-01

The molecular weight (MW) of dissolved organic matter (DOM) is considered as an important factor affecting the bioavailability of organic matter and associated chemical species. Colored DOM (CDOM) MW distribution was determined, for the first time, in the Beaufort Sea (Canada Basin) by asymmetrical flow field-flow fractionation (AF4) coupled with online diode array ultra violet-visible photometer and offline fluorescence detectors. The apparent MW ranged from 1.07 to 1.45 kDa, congruent with previous studies using high performance size exclusion chromatography and tangential flow filtration. Interestingly, a minimum in MW was associated with the Pacific Summer Waters (PSW), while higher MW was associated with the Pacific Winter Waters (PWW). The Arctic Intermediate Waters (AIW) did not show any significant change in MW and fluorescence intensities distribution between stations, suggesting homogeneous DOM composition in deep waters. Three fluorescence components including two humic-like components and one protein-like component were PARAFAC-validated. With the increase of MW, protein-like fluorescence component became more dominant while the majority remained as marine/microbially derived humic-like components. Overall, it is concluded that water mass origin influenced DOM MW distribution in the Arctic Ocean.

Phocine distemper virus: current knowledge and future directions.

PubMed

Duignan, Pádraig J; Van Bressem, Marie-Françoise; Baker, Jason D; Barbieri, Michelle; Colegrove, Kathleen M; De Guise, Sylvain; de Swart, Rik L; Di Guardo, Giovanni; Dobson, Andrew; Duprex, W Paul; Early, Greg; Fauquier, Deborah; Goldstein, Tracey; Goodman, Simon J; Grenfell, Bryan; Groch, Kátia R; Gulland, Frances; Hall, Ailsa; Jensen, Brenda A; Lamy, Karina; Matassa, Keith; Mazzariol, Sandro; Morris, Sinead E; Nielsen, Ole; Rotstein, David; Rowles, Teresa K; Saliki, Jeremy T; Siebert, Ursula; Waltzek, Thomas; Wellehan, James F X

2014-12-22

Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.

Phocine Distemper Virus: Current Knowledge and Future Directions

PubMed Central

Duignan, Pádraig J.; Van Bressem, Marie-Françoise; Baker, Jason D.; Barbieri, Michelle; Colegrove, Kathleen M.; De Guise, Sylvain; de Swart, Rik L.; Di Guardo, Giovanni; Dobson, Andrew; Duprex, W. Paul; Early, Greg; Fauquier, Deborah; Goldstein, Tracey; Goodman, Simon J.; Grenfell, Bryan; Groch, Kátia R.; Gulland, Frances; Hall, Ailsa; Jensen, Brenda A.; Lamy, Karina; Matassa, Keith; Mazzariol, Sandro; Morris, Sinead E.; Nielsen, Ole; Rotstein, David; Rowles, Teresa K.; Saliki, Jeremy T.; Siebert, Ursula; Waltzek, Thomas; Wellehan, James F.X.

2014-01-01

Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years. PMID:25533658

India: Asia-Pacific energy series country report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gazdar, M.N.

As part of our continuing assessment of Asia-Pacific energy markets, the Resources Programs of the East-West Center series of country studies that discuss in detail the structure of the energy sector. To date, our reports to the US Department of Energy, Assistant Secretary for International Affairs and Energy Emergencies, have covered Australia, China, India, Indonesia, Japan, Malaysia, New Zealand, Pakistan, the Philippines, Singapore, South Korea, Taiwan, and Thailand. The country studies provide an overview of the economic and political situation in the various countries. We have highlighted petroleum and gas issues in the country studies and have attempted to showmore » the foreign trade implications of oil and gas trade. To the greatest extent possible, we have provided the latest available statistics. Staff members have traveled extensively in-and at times have lived in-the countries under review and have held discussions with senior policymakers in government and industry. Thus, these reports provide not only information but also the latest thinking on energy issues in the various countries. Over the next few years these country studies can be updated and will provide a continuous, long-term source of energy sector analysis for the Asia-Pacific region. This India Asia-Pacific Energy Series Country Report is the follow-on to a study by Victor Lobo, Energy in India: The Oil Sector, which was published by the East-West Center in December 1989. The study focused on the petroleum industry, particularly refining, infrastructure, marketing and distribution, specifications of products, demand structure and pricing. This current study, must be seen as a supplement to our 1989 study and, as such, does not cover the petroleum sector in depth.« less

Oceanographic structure drives the assembly processes of microbial eukaryotic communities

PubMed Central

Monier, Adam; Comte, Jérôme; Babin, Marcel; Forest, Alexandre; Matsuoka, Atsushi; Lovejoy, Connie

2015-01-01

Arctic Ocean microbial eukaryote phytoplankton form subsurface chlorophyll maximum (SCM), where much of the annual summer production occurs. This SCM is particularly persistent in the Western Arctic Ocean, which is strongly salinity stratified. The recent loss of multiyear sea ice and increased particulate-rich river discharge in the Arctic Ocean results in a greater volume of fresher water that may displace nutrient-rich saltier waters to deeper depths and decrease light penetration in areas affected by river discharge. Here, we surveyed microbial eukaryotic assemblages in the surface waters, and within and below the SCM. In most samples, we detected the pronounced SCM that usually occurs at the interface of the upper mixed layer and Pacific Summer Water (PSW). Poorly developed SCM was seen under two conditions, one above PSW and associated with a downwelling eddy, and the second in a region influenced by the Mackenzie River plume. Four phylogenetically distinct communities were identified: surface, pronounced SCM, weak SCM and a deeper community just below the SCM. Distance–decay relationships and phylogenetic structure suggested distinct ecological processes operating within these communities. In the pronounced SCM, picophytoplanktons were prevalent and community assembly was attributed to water mass history. In contrast, environmental filtering impacted the composition of the weak SCM communities, where heterotrophic Picozoa were more numerous. These results imply that displacement of Pacific waters to greater depth and increased terrigenous input may act as a control on SCM development and result in lower net summer primary production with a more heterotroph dominated eukaryotic microbial community. PMID:25325383

Migration trends of Sockeye Salmon at the northern edge of their distribution

USGS Publications Warehouse

Carey, Michael P.; Zimmerman, Christian E.; Keith, Kevin D.; Schelske, Merlyn; Lean, Charles; Douglas, David C.

2017-01-01

Climate change is affecting arctic and subarctic ecosystems, and anadromous fish such as Pacific salmon Oncorhynchus spp. are particularly susceptible due to the physiological challenge of spawning migrations. Predicting how migratory timing will change under Arctic warming scenarios requires an understanding of how environmental factors drive salmon migrations. Multiple mechanisms exist by which environmental conditions may influence migrating salmon, including altered migration cues from the ocean and natal river. We explored relationships between interannual variability and annual migration timing (2003–2014) of Sockeye Salmon O. nerka in a subarctic watershed with environmental conditions at broad, intermediate, and local spatial scales. Low numbers of Sockeye Salmon have returned to this high-latitude watershed in recent years, and run size has been a dominant influence on the migration duration and the midpoint date of the run. The duration of the migration upriver varied by as much as 25 d across years, and shorter run durations were associated with smaller run sizes. The duration of the migration was also extended with warmer sea surface temperatures in the staging area and lower values of the North Pacific Index. The midpoint date of the total run was earlier when the run size was larger, whereas the midpoint date was delayed during years in which river temperatures warmed earlier in the season. Documenting factors related to the migration of Sockeye Salmon near the northern limit of their range provides insights into the determinants of salmon migrations and suggests processes that could be important for determining future changes in arctic and subarctic ecosystems.

Role of extratropical cyclones in the recently observed increase in poleward moisture transport into the Arctic Ocean

NASA Astrophysics Data System (ADS)

Villamil-Otero, Gian A.; Zhang, Jing; He, Juanxiong; Zhang, Xiangdong

2018-01-01

Poleward atmospheric moisture transport (AMT) into the Arctic Ocean can change atmospheric moisture or water vapor content and cause cloud formation and redistribution, which may change downward longwave radiation and, in turn, surface energy budgets, air temperatures, and sea-ice production and melt. In this study, we found a consistently enhanced poleward AMT across 60°N since 1959 based on the NCAR-NCEP reanalysis. Regional analysis demonstrates that the poleward AMT predominantly occurs over the North Atlantic and North Pacific regions, contributing about 57% and 32%, respectively, to the total transport. To improve our understanding of the driving force for this enhanced poleward AMT, we explored the role that extratropical cyclone activity may play. Climatologically, about 207 extratropical cyclones move across 60°N into the Arctic Ocean each year, among which about 66 (32% of the total) and 47 (23%) originate from the North Atlantic and North Pacific Ocean, respectively. When analyzing the linear trends of the time series constructed by using a 20-year running window, we found a positive correlation of 0.70 between poleward yearly AMT and the integrated cyclone activity index (measurement of cyclone intensity, number, and duration). This shows the consistent multidecadal changes between these two parameters and may suggest cyclone activity plays a driving role in the enhanced poleward AMT. Furthermore, a composite analysis indicates that intensification and poleward extension of the Icelandic low and accompanying strengthened cyclone activity play an important role in enhancing poleward AMT over the North Atlantic region.

Influence of atmospheric energy transport on amplification of winter warming in the Arctic

NASA Astrophysics Data System (ADS)

Alekseev, Genrikh; Kuzmina, Svetlana; Urazgildeeva, Aleksandra; Bobylev, Leonid

2016-04-01

The study was performed on base reanalysis ERA/Interim to discover the link between amplified warming in the high Arctic and the atmospheric transport of heat and water vapor through the 70 ° N. The partitioning transports across the Atlantic and Pacific "gates" is established the link between variations of atmospheric flux through the "gates" and a larger part of the variability of the average surface air temperature, water vapor content and its trends in the winter 1980-2014. Influence of winter (December-February) atmospheric transport across the Atlantic "gate" at the 1000 hPa on variability of average for January-February surface air temperature to north 70° N is estimated correlation coefficient 0.75 and contribution to the temperature trend 40%. These results for the first time denote the leading role of increasing atmospheric transport on the amplification of winter warming in the high Arctic. The investigation is supported with RFBR project 15-05-03512.

Levoglucosan indicates high levels of biomass burning aerosols over oceans from the Arctic to Antarctic

PubMed Central

Hu, Qi-Hou; Xie, Zhou-Qing; Wang, Xin-Ming; Kang, Hui; Zhang, Pengfei

2013-01-01

Biomass burning is known to affect air quality, global carbon cycle, and climate. However, the extent to which biomass burning gases/aerosols are present on a global scale, especially in the marine atmosphere, is poorly understood. Here we report the molecular tracer levoglucosan concentrations in marine air from the Arctic Ocean through the North and South Pacific Ocean to Antarctica during burning season. Levoglucosan was found to be present in all regions at ng/m3 levels with the highest atmospheric loadings present in the mid-latitudes (30°–60° N and S), intermediate loadings in the Arctic, and lowest loadings in the Antarctic and equatorial latitudes. As a whole, levoglucosan concentrations in the Southern Hemisphere were comparable to those in the Northern Hemisphere. Biomass burning has a significant impact on atmospheric Hg and water-soluble organic carbon (WSOC) from pole-to-pole, with more contribution to WSOC in the Northern Hemisphere than in the Southern Hemisphere. PMID:24176935

Levoglucosan indicates high levels of biomass burning aerosols over oceans from the Arctic to Antarctic.

PubMed

Hu, Qi-Hou; Xie, Zhou-Qing; Wang, Xin-Ming; Kang, Hui; Zhang, Pengfei

2013-11-01

Biomass burning is known to affect air quality, global carbon cycle, and climate. However, the extent to which biomass burning gases/aerosols are present on a global scale, especially in the marine atmosphere, is poorly understood. Here we report the molecular tracer levoglucosan concentrations in marine air from the Arctic Ocean through the North and South Pacific Ocean to Antarctica during burning season. Levoglucosan was found to be present in all regions at ng/m(3) levels with the highest atmospheric loadings present in the mid-latitudes (30°-60° N and S), intermediate loadings in the Arctic, and lowest loadings in the Antarctic and equatorial latitudes. As a whole, levoglucosan concentrations in the Southern Hemisphere were comparable to those in the Northern Hemisphere. Biomass burning has a significant impact on atmospheric Hg and water-soluble organic carbon (WSOC) from pole-to-pole, with more contribution to WSOC in the Northern Hemisphere than in the Southern Hemisphere.

A Review of Magnetic Anomaly Field Data for the Arctic Region: Geological Implications

NASA Technical Reports Server (NTRS)

Taylor, Patrick T.; vonFrese, Ralph; Roman, Daniel; Frawley, James J.

1999-01-01

Due to its inaccessibility and hostile physical environment remote sensing data, both airborne and satellite measurements, has been the main source of geopotential data over the entire Arctic region. Ubiquitous and significant external fields, however, hinder crustal magnetic field studies. These potential field data have been used to derive tectonic models for the two major tectonic sectors of this region, the Amerasian and Eurasian Basins. The latter is dominated by the Nansen-Gakkel or Mid-Arctic Ocean Ridge and is relatively well known. The origin and nature of the Alpha and Mendeleev Ridges, Chukchi Borderland and Canada Basin of the former are less well known and a subject of controversy. The Lomonosov Ridge divides these large provinces. In this report we will present a summary of the Arctic geopotential anomaly data derived from various sources by various groups in North America and Europe and show how these data help us unravel the last remaining major puzzle of the global plate tectonic framework. While Magnetic anomaly data represent the main focus of this study recently derived satellite gravity data (Laxon and McAdoo, 1998) are playing a major role in Arctic studies.

Changing Sea Ice Conditions in the Northwest Passage

NASA Astrophysics Data System (ADS)

Tivy, A. C.; Howell, S.; Agnew, T.; Derksen, C.

2010-12-01

The Northwest Passage lies in the middle of Canadian Arctic Archipelago providing a potential deepwater route that links the Atlantic and Pacific Oceans. Discovered by Sir Robert M’Clure in the 1850s, ever-present multi-year ice (MYI) has always prevented its practical navigation. 2007 marked extreme low MYI conditions in the Arctic and temporarily cleared the Northwest Passage. However, is one single clearing event within the Northwest Passage over the past 40 years indicative of future clearings? This analysis addressed two inter-related questions: i) why has the Northwest Passage contained historically heavy amounts of MYI? and ii) will decreases in MYI within the Northwest Passage continue into the future? Results indicate that for nearly 4 decades, the southern regions of the Canadian Arctic Archipelago have continuously operated as a drain-trap for MYI and this mechanism is responsible for maintaining the heavy MYI conditions within the Northwest Passage. The oldest and thickest MYI in the world resides along the northern flank of the Canadian Arctic Archipelago therefore, as the transition to a sea ice-free Arctic continues, MYI from this region will continue to migrate southward to the channels of the Northwest Passage. Results also find that 2007 was indeed an anomalously light sea ice year in the Northwest Passage but record low ice conditions have since been observed as of mid-August 2010.

Geological Structure and History of the Arctic Ocean

NASA Astrophysics Data System (ADS)

Petrov, Oleg; Morozov, Andrey; Shokalsky, Sergey; Sobolev, Nikolay; Kashubin, Sergey; Pospelov, Igor; Tolmacheva, Tatiana; Petrov, Eugeny

2016-04-01

New data on geological structure of the deep-water part of the Arctic Basin have been integrated in the joint project of Arctic states - the Atlas of maps of the Circumpolar Arctic. Geological (CGS, 2009) and potential field (NGS, 2009) maps were published as part of the Atlas; tectonic (Russia) and mineral resources (Norway) maps are being completed. The Arctic basement map is one of supplements to the tectonic map. It shows the Eurasian basin with oceanic crust and submerged margins of adjacent continents: the Barents-Kara, Amerasian ("Amerasian basin") and the Canada-Greenland. These margins are characterized by strained and thinned crust with the upper crust layer, almost extinct in places (South Barents and Makarov basins). In the Central Arctic elevations, seismic studies and investigation of seabed rock samples resulted in the identification of a craton with the Early Precambrian crust (near-polar part of the Lomonosov Ridge - Alpha-Mendeleev Rise). Its basement presumably consists of gneiss granite (2.6-2.2 Ga), and the cover is composed of Proterozoic quartzite sandstone and dolomite overlain with unconformity and break in sedimentation by Devonian-Triassic limestone with fauna and terrigenous rocks. The old crust is surrounded by accretion belts of Timanides and Grenvillides. Folded belts with the Late Precambrian crust are reworked by Caledonian-Ellesmerian and the Late Mesozoic movements. Structures of the South Anuy - Angayucham ophiolite suture reworked in the Early Cretaceous are separated from Mesozoides proper of the Pacific - Verkhoyansk-Kolyma and Koryak-Kamchatka belts. The complicated modern ensemble of structures of the basement and the continental frame of the Arctic Ocean was formed as a result of the conjugate evolution and interaction of the three major oceans of the Earth: Paleoasian, Paleoatlantic and Paleopacific.

Assessment of Arctic and Antarctic Sea Ice Predictability in CMIP5 Decadal Hindcasts

NASA Technical Reports Server (NTRS)

Yang, Chao-Yuan; Liu, Jiping (Inventor); Hu, Yongyun; Horton, Radley M.; Chen, Liqi; Cheng, Xiao

2016-01-01

This paper examines the ability of coupled global climate models to predict decadal variability of Arctic and Antarctic sea ice. We analyze decadal hindcasts/predictions of 11 Coupled Model Intercomparison Project Phase 5 (CMIP5) models. Decadal hindcasts exhibit a large multimodel spread in the simulated sea ice extent, with some models deviating significantly from the observations as the predicted ice extent quickly drifts away from the initial constraint. The anomaly correlation analysis between the decadal hindcast and observed sea ice suggests that in the Arctic, for most models, the areas showing significant predictive skill become broader associated with increasing lead times. This area expansion is largely because nearly all the models are capable of predicting the observed decreasing Arctic sea ice cover. Sea ice extent in the North Pacific has better predictive skill than that in the North Atlantic (particularly at a lead time of 3-7 years), but there is a reemerging predictive skill in the North Atlantic at a lead time of 6-8 years. In contrast to the Arctic, Antarctic sea ice decadal hindcasts do not show broad predictive skill at any timescales, and there is no obvious improvement linking the areal extent of significant predictive skill to lead time increase. This might be because nearly all the models predict a retreating Antarctic sea ice cover, opposite to the observations. For the Arctic, the predictive skill of the multi-model ensemble mean outperforms most models and the persistence prediction at longer timescales, which is not the case for the Antarctic. Overall, for the Arctic, initialized decadal hindcasts show improved predictive skill compared to uninitialized simulations, although this improvement is not present in the Antarctic.

Contemporary Arctic Sea Level

NASA Astrophysics Data System (ADS)

Cazenave, A. A.

2017-12-01

During recent decades, the Arctic region has warmed at a rate about twice the rest of the globe. Sea ice melting is increasing and the Greenland ice sheet is losing mass at an accelerated rate. Arctic warming, decrease in the sea ice cover and fresh water input to the Arctic ocean may eventually impact the Arctic sea level. In this presentation, we review our current knowledge of contemporary Arctic sea level changes. Until the beginning of the 1990s, Arctic sea level variations were essentially deduced from tide gauges located along the Russian and Norwegian coastlines. Since then, high inclination satellite altimetry missions have allowed measuring sea level over a large portion of the Arctic Ocean (up to 80 degree north). Measuring sea level in the Arctic by satellite altimetry is challenging because the presence of sea ice cover limits the full capacity of this technique. However adapted processing of raw altimetric measurements significantly increases the number of valid data, hence the data coverage, from which regional sea level variations can be extracted. Over the altimetry era, positive trend patterns are observed over the Beaufort Gyre and along the east coast of Greenland, while negative trends are reported along the Siberian shelf. On average over the Arctic region covered by satellite altimetry, the rate of sea level rise since 1992 is slightly less than the global mea sea level rate (of about 3 mm per year). On the other hand, the interannual variability is quite significant. Space gravimetry data from the GRACE mission and ocean reanalyses provide information on the mass and steric contributions to sea level, hence on the sea level budget. Budget studies show that regional sea level trends over the Beaufort Gyre and along the eastern coast of Greenland, are essentially due to salinity changes. However, in terms of regional average, the net steric component contributes little to the observed sea level trend. The sea level budget in the Arctic indicates a dominant mass contribution, especially in the Greenland, Norwegian, and Barents Seas sector.

Hanna Shoal: An integrative study of a High Arctic marine ecosystem in the Chukchi Sea

NASA Astrophysics Data System (ADS)

Dunton, Kenneth H.; Grebmeier, Jacqueline M.; Trefry, John H.

2017-10-01

This second special issue on the ecosystem under the COMIDA (Chukchi Sea Offshore Monitoring in the Drilling Area) Project focuses on the productive region around Hanna Shoal, the northernmost shoal on the Chukchi shelf. Our first issue (Dunton et al., 2014) emphasized the chemical and biological characteristics of the northeastern Chukchi Sea benthos. This effort expands our studies on the unique physical oceanography of Hanna Shoal, which lies at the interface between northward flowing Pacific Water and the Arctic Ocean, to include its influence on zooplankton dynamics and higher trophic level biota. Between both studies, conducted over a 5-year period (2009-2013) and four summer cruises, COMIDA scientists from seven institutions occupied some 85 stations (Fig. 1).

A Two Time-scale response of the Southern Ocean to the Ozone Hole: Regional Responses and Mechanisms

NASA Astrophysics Data System (ADS)

Gnanadesikan, A.; Seviour, W.; Waugh, D.; Pradal, M. A. S.

2016-12-01

The impact of changing ozone on the climate of the Southern Ocean is evaluated using an ensemble of coupled climate models. By imposing a step change from 1860 to 2000 conditions we are able to estimate response functions associated with this change. Two time scales are found, an initial cooling centered in the Southwest Pacific followed by cooling in the Pacific sector and then warming in both sectors. The physical processes that drive this response are different across time periods and locations, as is the sign of the response itself. Initial cooling in the Pacific sector is not just driven by the increased winds pushing cold water northward, but also by a decrease in surface salinity reducing wintertime mixing and increased ice and clouds reflecting more shortwave radiation back to space. The decrease in salinity is primarily driven by a southward shift of precipitation associated with a shifting storm track, coupled with decreased evaporation associated with colder surface temperatures. A subsurface increase in heat associated with this reduction in mixing then upwells along the Antarctic coast, producing a subsequent warming. Similar changes in convective activity occur in the Weddell Sea but are offset in time.

Teaching about Japan. ERIC Digest No. 38.

ERIC Educational Resources Information Center

Wojtan, Linda S.

This is an age of ascendency of the Pacific Rim area, especially the Asian sector. Recent decades have seen unprecedented economic growth throughout this area. By examining Japan, the region's pre-eminent nation and harbinger of future developments, the larger topic of the Pacific Rim can be explored. It is particularly important to teach about…

76 FR 62374 - Proposed Information Collection; Comment Request; Alaska Recreational Charter Vessel Guide and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-07

... charter vessels in the guided halibut sport fishery in International Pacific Halibut Commission Areas 2C... Pacific halibut is allocated between the guided sport (i.e., the charter sector) and the commercial... Fisheries Science Center proposes to conduct a survey of charter vessel owners to collect annual cost and...

New Partnerships and Education Policy in Asia and the Pacific

ERIC Educational Resources Information Center

Cassity, Elizabeth

2010-01-01

Forming more effective partnerships with national governments in the Asia-Pacific region has been an important policy focus for the Australian Agency for International Development (AusAID) since 2006. AusAID is increasingly engaging in sector-wide approaches and working through partner government systems. This paper explores how new partnerships…

Agroforestry In-Service Training. A Training Aid for Asia & the Pacific Islands (Honiara, Solomon Islands, South Pacific, October 23-29, 1983). Training for Development. Peace Corps Information Collection & Exchange Training Manual No. T-16.

ERIC Educational Resources Information Center

Fillion, Jacob; Weeks, Julius

The Forestry/Natural Resources Sector in the Office of Training and Program Support of the Peace Corps conducted an agroforestry inservice training workshop in Honiara, Solomon Islands, in 1983. Participants included Peace Corps volunteers and their host country national counterparts from six countries of the Pacific Islands and Asia (Western…

Increasing cloudiness in Arctic damps the increase in phytoplankton primary production due to sea ice receding

NASA Astrophysics Data System (ADS)

Bélanger, S.; Babin, M.; Tremblay, J.-É.

2013-06-01

The Arctic Ocean and its marginal seas are among the marine regions most affected by climate change. Here we present the results of a diagnostic model used to assess the primary production (PP) trends over the 1998-2010 period at pan-Arctic, regional and local (i.e. 9.28 km resolution) scales. Photosynthetically active radiation (PAR) above and below the sea surface was estimated using precomputed look-up tables of spectral irradiance, taking as input satellite-derived cloud optical thickness and cloud fraction parameters from the International Satellite Cloud Climatology Project (ISCCP) and sea ice concentration from passive microwaves data. A spectrally resolved PP model, designed for optically complex waters, was then used to assess the PP trends at high spatial resolution. Results show that PP is rising at a rate of +2.8 TgC yr-1 (or +14% decade-1) in the circum-Arctic and +5.1 TgC yr-1 when sub-Arctic seas are considered. In contrast, incident PAR above the sea surface (PAR(0+)) has significantly decreased over the whole Arctic and sub-Arctic Seas, except over the perennially sea-ice covered waters of the Central Arctic Ocean. This fading of PAR(0+) (-8% decade-1) was caused by increasing cloudiness during summer. Meanwhile, PAR penetrating the ocean (PAR(0-)) increased only along the sea ice margin over the large Arctic continental shelf where sea ice concentration declined sharply since 1998. Overall, PAR(0-) slightly increased in the circum-Arctic (+3.4% decade-1), while it decreased when considering both Arctic and sub-Arctic Seas (-3% decade-1). We showed that rising phytoplankton biomass (i.e. chlorophyll a) normalized by the diffuse attenuation of photosynthetically usable radiation (PUR), accounted for a larger proportion of the rise in PP than did the increase in light availability due to sea-ice loss in several sectors, and particularly in perennially and seasonally open waters. Against a general backdrop of rising productivity over Arctic shelves, significant negative PP trends and the timing of phytoplankton spring-summer bloom were observed in regions known for their great biological importance such as the coastal polynyas of northern Greenland.

Arctic climatechange and its impacts on the ecology of the North Atlantic.

PubMed

Greene, Charles H; Pershing, Andrew J; Cronin, Thomas M; Ceci, Nicole

2008-11-01

Arctic climate change from the Paleocene epoch to the present is reconstructed with the objective of assessing its recent and future impacts on the ecology of the North Atlantic. A recurring theme in Earth's paleoclimate record is the importance of the Arctic atmosphere, ocean, and cryosphere in regulating global climate on a variety of spatial and temporal scales. A second recurring theme in this record is the importance of freshwater export from the Arctic in regulating global- to basin-scale ocean circulation patterns and climate. Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea-ice melting. In addition, modal shifts in the atmosphere have altered Arctic Ocean circulation patterns and the export of freshwater into the North Atlantic. The combination of these processes has resulted in variable patterns of freshwater export from the Arctic Ocean and the emergence of salinity anomalies that have periodically freshened waters in the North Atlantic. Since the early 1990s, changes in Arctic Ocean circulation patterns and freshwater export have been associated with two types of ecological responses in the North Atlantic. The first of these responses has been an ongoing series of biogeographic range expansions by boreal plankton, including renewal of the trans-Arctic exchanges of Pacific species with the Atlantic. The second response was a dramatic regime shift in the shelf ecosystems of the Northwest Atlantic that occurred during the early 1990s. This regime shift resulted from freshening and stratification of the shelf waters, which in turn could be linked to changes in the abundances and seasonal cycles of phytoplankton, zooplankton, and higher trophic-level consumer populations. It is predicted that the recently observed ecological responses to Arctic climate change in the North Atlantic will continue into the near future if current trends in sea ice, freshwater export, and surface ocean salinity continue. It is more difficult to predict ecological responses to abrupt climate change in the more distant future as tipping points in the Earth's climate system are exceeded.

Communicating Climate and Ecosystem Change in the Arctic

NASA Astrophysics Data System (ADS)

Soreide, N. N.; Overland, J. E.; Calder, J. A.; Rodionov, S.

2005-12-01

There is an explosion of interest in Northern Hemisphere climate, highlighting the importance of recent changes in the Arctic on mid-latitude climate and its impact on marine and terrestrial ecosystems. Traditional sea ice and tundra dominated arctic ecosystems are being reorganizing into warmer sub-arctic ecosystem types. Over the previous two years we have developed a comprehensive, near real-time arctic change detection protocol to track physical and biological changes for presentation on the web: http://www.arctic.noaa.gov/detect. The effort provides a continuous update to the Arctic Climate Impact Assessment (ACIA) Report, released in November 2004. Principles for the protocol include an accessible narrative style, scientifically credible and objective indicators, notes multiple uses for the information, acknowledges uncertainties, and balances having too many indicators-which leads to information overload-and too few-which does not capture the complexity of the system. Screening criteria include concreteness, public awareness, being understandable, availability of historical time series, and sensitivity. The site provides sufficient information for an individual to make their own assessment regarding the balance of the evidence for tracking change. The product provides an overview, recent news, links to many arctic websites, and highlights climate, global impacts, land and marine ecosystems, and human consequences. Since its inception a year ago, it has averaged about 9000 hits an day on the web, and is a major information source as determined by Google search. The future direction focuses on understanding the causes for change. In spring 2005 we also presented a near real-time ecological and climatic surveillance website for the Bering Sea: www.beringclimate.noaa.gov. The site provides up-to-date information which ties northward shifts of fish, invertebrate and marine mammal populations to physical changes in the Arctic. This site is more technical than the arctic change detection site and provides support to the North Pacific Fisheries Management Council and other interested parties. The site anticipates multiple uses by providing access and analysis tools for a set of Bering Sea indicator time series.

Trophodynamics of some PFCs and BFRs in a western Canadian Arctic marine food web.

PubMed

Tomy, Gregg T; Pleskach, Kerri; Ferguson, Steve H; Hare, Jonathon; Stern, Gary; Macinnis, Gordia; Marvin, Chris H; Loseto, Lisa

2009-06-01

The trophodynamics of per- and polyfluorinated compounds and bromine-based flame retardants were examined in components of a marine food web from the western Canadian Arctic. The animals studied and their relative trophic status in the food web, established using stable isotopes of nitrogen (delta15N), were beluga (Delphinapterus leucas) > ringed seal (Phoca hispida) > Arctic cod (Boreogadus saida) > Pacific herring (Clupea pallasi) approximately equal to Arctic cisco (Coregonus autumnalis) > pelagic amphipod (Themisto libellula) > Arctic copepod (Calanus hyperboreus). For the brominated diphenyl ethers, the lipid adjusted concentrations of the seven congeners analyzed (Sigma7BDEs: -47, -85, -99, -100, -153, -154, and -209) ranged from 205.4 +/- 52.7 ng/g in Arctic cod to 2.6 +/- 0.4 ng/g in ringed seals. Mean Sigma7BDEs concentrations in Arctic copepods, 16.4 ng/g (n = 2, composite sample), were greater than those in the top trophic level (TL) marine mammals and suggests that (i) Arctic copepods are an important dietary component that delivers BDEs to the food web and (ii) because these compounds are bioaccumulative, metabolism and depletion of BDE congeners in top TL mammals is an important biological process. There were differences in the concentration profiles of the isomers of hexabromocyclododecane (HBCD) in the food web. The most notable difference was observed for beluga, where the alpha-isomer was enriched (accounting for approximately 90% of the SigmaHBCD body burden), relative to its primary prey species, Arctic cod, where the alpha-isomer accounted for only 20% of the SigmaHBCD body burden (beta: 4% and gamma: 78%). For the C8-C11 perfluorinated carboxylic acids, the trophic magnification factors (TMFs) were all greater than unity and increased with increasing carbon chain length. PFOS and its neutral precursor, PFOSA, also had TMF values greater than one. There were also pronounced differences in the PFOSA to PFOS ratio in ringed seal (0.04) and in beluga (1.4) and suggests that, in part, there are differences in the efficacy of biotransforming PFOSA by whale and seal top predators that both preferentially feed on Arctic cod.

Aminostratigraphy and faunal correlations of late Quaternary marine terraces, Pacific Coast, USA

USGS Publications Warehouse

Kennedy, G.L.; Lajoie, K.R.; Wehmiller, J.F.

1982-01-01

Recent studies using the extent of racemization of amino acids to date fossil mollusc shells in the Arctic1, the British Isles2 and on the Atlantic3,4 and Pacific5-13 coasts of North America have relied mainly on theoretical kinetic models of racemization. Ages generated in this fashion are highly model dependent and require estimates of integrated long-term diagenetic temperatures. We present here an alternative, empirical approach to aminostratigraphy in which we plot amino acid enantiomeric ratios versus latitude (for localities along the Pacific coast of the United States), and generate isochronal correlations by connecting data points of geographically proximal localities that have similar D:L ratios and zoogeographic aspect. Isochrons are calibrated at a few localities by independent radiometric dates. The diagenetic temperature effect on racemization is reflected in the slope of the isochrons, but the need to quantify temperature is eliminated. ?? 1982 Nature Publishing Group.

Observations of Cirrus Clouds over the Pacific Region by the NASA Multiwavelength Lidar System

NASA Technical Reports Server (NTRS)

Ismail, Syed; Browell, Edward V.; Fenn, Marta A.; Nowicki, Greg D.

1992-01-01

As part of the Pacific Exploratory Mission-West Campaign that took place during 16 Sep. - 21 Oct. 1991, lidar measurements were made from the ARC DC-8 aircraft at an altitude of approximately 9 km. This mission provided a unique opportunity to make cirrus cloud observations around the Pacific region covering the latitude range from 5 to 55 deg N and the longitude range from -114 to 120 deg E. Cirrus clouds were observed on most of these flights providing a unique data base. The latitudinal coverage of cirrus observations was further extended to -5 deg S from observations on 30 Jan. 1992 as part of the Airborne Arctic Stratospheric Expedition 2. During this latter mission, aerosol depolarizations at 622 and 1064 nm were also measured. The optical characteristics and statistics related to these cirrus cloud observations are summarized.

Non-government organisation engagement in the sanitation sector: opportunities to maximise benefits.

PubMed

Carrard, N; Pedi, D; Willetts, J; Powell, B

2009-01-01

Non-government organisations (NGOs) have long played a role in delivering sanitation services to communities in Southeast Asia and Pacific countries, particularly in rural areas. In contrast with large scale infrastructure focused initiatives, NGO programs commonly focus on building linkages between technical and social realms. Drawing on the breadth and depth of NGO experiences, there are opportunities for NGOs to play a greater role in the sanitation sector and to work in partnership with other actors including utilities and government agencies to ensure both 'hardware' and 'software' components of sanitation are built in to project design and delivery to maximise community benefits and ensure longer term system sustainability. This paper discusses these issues and considers how the contribution of NGOs to the sanitation sector in developing countries might be enhanced. The paper is based on recent research for the Australian Agency for International Development (AusAID) intended to guide investment in the water and sanitation sectors of Asia and Pacific partner countries, exploring the potential for increased NGO engagement. The paper presents findings of the research concerning NGO roles and approaches, discusses existing NGO activities in the sanitation sector in Vietnam and Timor Leste and identifies strategies for NGOs and for other sector actors including utilities and government agencies to maximise the benefits of NGO engagement in the sanitation sector.

Continental Evolution Involving Subduction Underplating and Synchronous Foreland Thrusting: Evidence from the Trans-Alaska Crustal Transect

NASA Astrophysics Data System (ADS)

Fuis, G. S.; Moore, T. E.; Plafker, G.; Brocher, T. M.; Fisher, M. A.; Mooney, W. D.; Nokleberg, W. J.; Page, R. A.; Beaudoin, B. C.; Christensen, N. I.; Levander, A.; Lutter, W. J.; Saltus, R. W.; Ruppert, N. A.

2010-12-01

We investigated the crustal structure and tectonic evolution of the North American continent in Alaska, where the continent has grown through magmatism, accretion, and tectonic underplating. In the 1980’s and early 1990’s, we conducted a geological and geophysical investigation, known as the Trans-Alaska Crustal Transect (TACT), along a 1350-km-long corridor from the Aleutian Trench to the Arctic coast. The most distinctive crustal structures and the deepest Moho along the transect are located near the Pacific and Arctic margins. Near the Pacific margin, we infer a stack of tectonically underplated oceanic layers interpreted to be remnants of the extinct Kula (or Resurrection) Plate. Continental Moho just north of this underplated stack is more than 55 km deep. Near the Arctic margin, the Brooks Range is underlain by north-vergent, crustal-scale duplexes that overlie a ramp on autochthonous North Slope crust. There, Moho has been depressed to nearly 50-km depth. In contrast, the Moho of central Alaska is on average 32 km deep. In the Paleogene, tectonic underplating of Kula- (or Resurrection-) Plate fragments overlapped in time with duplexing in the Brooks Range. Possible tectonic models linking these two widely separated regions include “flat-slab” subduction and an “orogenic-float” model. In the Neogene, the collision of the Yakutat terrane (YAK), in southern Alaska, correlates with renewed compression in northeast Alaska and northwest Canada, in a fashion somewhat similar to the tectonics in the Paleogene. The Yakutat terrane, riding atop the subducting Pacific oceanic lithosphere (POL), spans a newly interpreted tear in the POL. East of the tear, POL is interpreted to subduct steeply and alone beneath the Wrangell arc volcanoes because the overlying YAK has been left behind as tectonically underplated rocks beneath the rising St. Elias Range in the coastal region. West of the tear, the YAK and POL are interpreted to subduct together at a gentle angle (a few degrees from 0 to 400 km from the trench), and this thickened package inhibits arc volcanism.

Occupancy of yellow-billed and Pacific loons: evidence for interspecific competition and habitat mediated co-occurrence

USGS Publications Warehouse

Haynes, Trevor B.; Schmutz, Joel A.; Lindberg, Mark S.; Wright, Kenneth G.; Uher-Koch, Brian D.; Rosenberger, Amanda E.

2014-01-01

Interspecific competition is an important process structuring ecological communities, however, it is difficult to observe in nature. We used an occupancy modelling approach to evaluate evidence of competition between yellow-billed (Gavia adamsii) and Pacific (G. pacifica) loons for nesting lakes on the Arctic Coastal Plain of Alaska. With multiple years of data and survey platforms, we estimated dynamic occupancy states (e.g. rates of colonization or extinction from individual lakes) and controlled for detection differences among aircraft platforms and ground survey crews. Results indicated that yellow-billed loons were strong competitors and negatively influenced the occupancy of Pacific loons by excluding them from potential breeding lakes. Pacific loon occupancy was conditional on the presence of yellow-billed loons, with Pacific loons having almost a tenfold decrease in occupancy probability when yellow-billed loons were present and a threefold decrease in colonization probability when yellow-billed loons were present in the current or previous year. Yellow-billed and Pacific loons co-occurred less than expected by chance except on very large lakes or lakes with convoluted shorelines; variables which may decrease the cost of maintaining a territory in the presence of the other species. These results imply the existence of interspecific competition between yellow-billed and Pacific loons for nesting lakes; however, habitat characteristics which facilitate visual and spatial separation of territories can reduce competitive interactions and promote species co-occurrence.

A qualitative examination of the health workforce needs during climate change disaster response in Pacific Island Countries

PubMed Central

2014-01-01

Background There is a growing body of evidence that the impacts of climate change are affecting population health negatively. The Pacific region is particularly vulnerable to climate change; a strong health-care system is required to respond during times of disaster. This paper examines the capacity of the health sector in Pacific Island Countries to adapt to changing disaster response needs, in terms of: (i) health workforce governance, management, policy and involvement; (ii) health-care capacity and skills; and (iii) human resources for health training and workforce development. Methods Key stakeholder interviews informed the assessment of the capacity of the health sector and disaster response organizations in Pacific Island Countries to adapt to disaster response needs under a changing climate. The research specifically drew upon and examined the adaptive capacity of individual organizations and the broader system of disaster response in four case study countries (Fiji, Cook Islands, Vanuatu and Samoa). Results ‘Capacity’ including health-care capacity was one of the objective determinants identified as most significant in influencing the adaptive capacity of disaster response systems in the Pacific. The research identified several elements that could support the adaptive capacity of the health sector such as: inclusive involvement in disaster coordination; policies in place for health workforce coordination; belief in their abilities; and strong donor support. Factors constraining adaptive capacity included: weak coordination of international health personnel; lack of policies to address health worker welfare; limited human resources and material resources; shortages of personnel to deal with psychosocial needs; inadequate skills in field triage and counselling; and limited capacity for training. Conclusion Findings from this study can be used to inform the development of human resources for health policies and strategic plans, and to support the development of a coordinated and collaborative approach to disaster response training across the Pacific and other developing contexts. This study also provides an overview of health-care capacity and some of the challenges and strengths that can inform future development work by humanitarian organizations, regional and international donors involved in climate change adaptation, and disaster risk reduction in the Pacific region. PMID:24521057

East Asian winter temperature variation associated with the combined effects of AO and WP pattern

NASA Astrophysics Data System (ADS)

Park, Hye-Jin; Ahn, Joong-Bae

2016-04-01

The combined effects of the Arctic Oscillation (AO) and Western Pacific (WP) teleconnection pattern on the East Asian winter monsoon (EAWM) over the last 56 years (1958/59-2013/2014) were investigated using NCEP/NCAR reanalysis data (Park and Ahn, 2015). The study results revealed that the effect of the AO on winter temperature in East Asia could be changed depending on the phases of the WP pattern in the North Pacific. The negative relationship between the EAWM and the AO increased when the AO and WP were in-phase with each other. Hence, when winter negative (positive) AO was accompanied by negative (positive) WP, negative (positive) temperature anomalies were dominant across the entire East Asia region. Conversely, when the AO and WP were of-of-phase, the winter temperature anomaly in East Asia did not show distinct changes. Furthermore, from the perspective of stationary planetary waves, the zonal wavenumber-2 patterns of sea level pressure and geopotential height at 500hPa circulation strengthened when the AO and WP were in-phase but were not significant for the out-of-phase condition. It explained the possible mechanism of the combined effects of the AO and WP on the circulation related to EAWM. Reference Park, H.-J., and J.-B. Ahn (2015) Combined effect of the Arctic Oscillation and the Western Pacific pattern on East Asia winter temperature, Clim. Dyn. DOI:10.1007/s00382-015-2763-2. Acknowledgements This work was funded by the Korea Meteorological Administration Research and Development Program under grant KMIPA2015-2081.

Projected status of the Pacific walrus (Odobenus rosmarus divergens) in the twenty-first century

USGS Publications Warehouse

Jay, Chadwick V.; Marcot, Bruce G.; Douglas, David C.

2011-01-01

Extensive and rapid losses of sea ice in the Arctic have raised conservation concerns for the Pacific walrus (Odobenus rosmarus divergens), a large pinniped inhabiting arctic and subarctic continental shelf waters of the Chukchi and Bering seas. We developed a Bayesian network model to integrate potential effects of changing environmental conditions and anthropogenic stressors on the future status of the Pacific walrus population at four periods through the twenty-first century. The model framework allowed for inclusion of various sources and levels of knowledge, and representation of structural and parameter uncertainties. Walrus outcome probabilities through the century reflected a clear trend of worsening conditions for the subspecies. From the current observation period to the end of century, the greatest change in walrus outcome probabilities was a progressive decrease in the outcome state of robust and a concomitant increase in the outcome state of vulnerable. The probabilities of rare and extirpated states each progressively increased but remained <10% through the end of the century. The summed probabilities of vulnerable, rare, and extirpated (P(v,r,e)) increased from a current level of 10% in 2004 to 22% by 2050 and 40% by 2095. The degree of uncertainty in walrus outcomes increased monotonically over future periods. In the model, sea ice habitat (particularly for summer/fall) and harvest levels had the greatest influence on future population outcomes. Other potential stressors had much smaller influences on walrus outcomes, mostly because of uncertainty in their future states and our current poor understanding of their mechanistic influence on walrus abundance.

Measurements of aerosol and CCN properties in the Mackenzie River delta (Canadian Arctic) during spring-summer transition in May 2014

NASA Astrophysics Data System (ADS)

Herenz, Paul; Wex, Heike; Henning, Silvia; Bjerring Kristensen, Thomas; Rubach, Florian; Roth, Anja; Borrmann, Stephan; Bozem, Heiko; Schulz, Hannes; Stratmann, Frank

2018-04-01

Within the framework of the RACEPAC (Radiation-Aerosol-Cloud Experiment in the Arctic Circle) project, the Arctic aerosol, arriving at a ground-based station in Tuktoyaktuk (Mackenzie River delta area, Canada), was characterized during a period of 3 weeks in May 2014. Basic meteorological parameters and particle number size distributions (PNSDs) were observed and two distinct types of air masses were found. One type were typical Arctic haze air masses, termed accumulation-type air masses, characterized by a monomodal PNSD with a pronounced accumulation mode at sizes above 100 nm. These air masses were observed during a period when back trajectories indicate an air mass origin in the north-east of Canada. The other air mass type is characterized by a bimodal PNSD with a clear minimum around 90 nm and with an Aitken mode consisting of freshly formed aerosol particles. Back trajectories indicate that these air masses, termed Aitken-type air masses, originated from the North Pacific. In addition, the application of the PSCF receptor model shows that air masses with their origin in active fire areas in central Canada and Siberia, in areas of industrial anthropogenic pollution (Norilsk and Prudhoe Bay Oil Field) and the north-west Pacific have enhanced total particle number concentrations (NCN). Generally, NCN ranged from 20 to 500 cm-3, while cloud condensation nuclei (CCN) number concentrations were found to cover a range from less than 10 up to 250 cm-3 for a supersaturation (SS) between 0.1 and 0.7 %. The hygroscopicity parameter κ of the CCN was determined to be 0.23 on average and variations in κ were largely attributed to measurement uncertainties. Furthermore, simultaneous PNSD measurements at the ground station and on the Polar 6 research aircraft were performed. We found a good agreement of ground-based PNSDs with those measured between 200 and 1200 m. During two of the four overflights, particle number concentrations at 3000 m were found to be up to 20 times higher than those measured below 2000 m; for one of these two flights, PNSDs measured above 2000 m showed a different shape than those measured at lower altitudes. This is indicative of long-range transport from lower latitudes into the Arctic that can advect aerosol from different regions in different heights.

75 FR 79341 - Proposed Information Collection; Comment Request; Harvest of Pacific Halibut by Guided Sport...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-20

... Collection; Comment Request; Harvest of Pacific Halibut by Guided Sport Charter Vessel Anglers off Alaska... halibut fishing effort and harvest by all user groups, including the guided sport charter sector of the... requirements. The State of Alaska Department of Fish and Game (ADF&G) Division of Sport Fish initiated a...

Opportunities for Partnership in the Pacific Rim: Reflections on a Visit to Vietnam.

ERIC Educational Resources Information Center

Sykes, Abel B., Jr.

Community colleges are poised to play a vital role in Vietnam and other Pacific Rim nations currently seeking to develop their business sectors and economies. Projects and partnerships with U.S. community colleges are currently in progress in India, Malaysia, China, Japan, Taiwan, and Korea. In addition, the Vietnamese Ministry of Education and…

Simulation of Arctic Black Carbon using Hemispheric CMAQ: Role of Russia's BC Emissions, Transport, and Deposition

NASA Astrophysics Data System (ADS)

Huang, K.; Fu, J. S.

2015-12-01

Black carbon plays a unique role in the Arctic climate system due to its multiple effects. It causes Arctic warming by directly absorbing sunlight from space and by darkening the surface albedo of snow and ice, which indirectly leads to further warming and melting, thus inducing an Arctic amplification effect. BC depositions over the Arctic are more sensitive to regions in close proximity. In this study, we reconstruct BC emissions for Russian Federation, which is the country that occupies the largest area in the Arctic Circle. Local Russia information such as activity data, emission factors and other emission source data are used. In 2010, total anthropogenic BC emission of Russia is estimated to be around 254 Gg. Gas flaring, a commonly ignored black carbon source, contributes a dominant 43.9% of Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 22.0%, 17.8%, 11.5%, and 4.8%, respectively. BC simulations were conducted using the hemispheric version of CMAQ with polar projection. Emission inputs are from a global emissions database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulations using the new Russian BC emission inventory could improve 46 - 61% of the Absorption Aerosol Optical Depth (AAOD) measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four air monitoring sites (Zeppelin, Barrow, Alert, and Tiksi) in the Arctic Circle, surface BC simulations are improved the most during the Arctic haze periods (October - March). Emission perturbation studies show that Russia's BC emissions contribute over 50% of the surface BC concentrations over the Arctic during the cold seasons. This study demonstrates the good capability of H-CMAQ in simulating the transport of BC particles to the Arctic and suggests that the impact of Russian emissions on the Arctic haze has likely been underestimated, which is one of the causes that previous modeling works struggled in reproducing the BC levels in the Arctic region.

Pacific patterns of dust deposition, iron supply and export production

NASA Astrophysics Data System (ADS)

Winckler, G.; Anderson, R. F.; Park, J.; Schwartz, R.; Pahnke, K.; Struve, T.; Lamy, F.; Gersonde, R.

2015-12-01

The scarcity of iron limits marine export production and carbon uptake in about a quarter of the global ocean where the surface concentration of nitrate and phosphate is high, as biological utilization of these macronutrients is incomplete. Of these high nutrient low chlorophyll (HNLC) regions, the Southern Ocean is the region where variations in iron availability can have the largest effect on Earth's carbon cycle through its fertilizing effect on marine ecosystems, both in the modern and in the past. Recent work in the Subantarctic South Atlantic (Martínez-Garcia et al., 2009, 2014, Anderson et al., 2014) suggests that dust-driven iron fertilization lowered atmospheric CO2 by up to 40 ppm in the latter half of each glacial cycle of the late Pleistocene, with the increase in Subantarctic productivity consuming a greater fraction of the surface nutrients and thus driving more storage of carbon in the ocean interior. The other sectors of the Southern Ocean remain poorly constrained, including the Pacific Sector, that accounts for the largest surface area of the Subantarctic Southern Ocean. Here we report records of dust deposition, iron supply and export production from a set of cores from the Subantarctic Pacific (PS75, Lamy et al 2014) and initial results about the origin of dust transported to the Subantarctic Pacific Ocean from radiogenic isotopes and rare earth elements. We test how tightly dust and biological productivity are coupled over glacial/interglacial and millennial timescales in the Subantarctic Pacific and place the region in a context of global patterns of biological productivity, nutrient utilization and iron fertilization by dust, including comparisons to the other Pacific HNLC regions, the Subarctic North Pacific and equatorial Pacific.

Response of Arctic Temperature to Changes in Emissions of Short-Lived Climate Forcers

NASA Astrophysics Data System (ADS)

Sand, M.; Berntsen, T.; von Salzen, K.; Flanner, M.; Langner, J.; Victor, D. G.

2015-12-01

There is growing scientific and political interest in the impacts of climate change and anthropogenic emissions on the Arctic. Over recent decades temperatures in the Arctic have increased twice the global rate, largely due to ice albedo and temperature feedbacks. While deep cuts in global CO2 emissions are required to slow this warming, there is also growing interest in the potential for reducing short lived climate forcers (SLCFs). Politically, action on SLCFs may be particularly promising because the benefits of mitigation appear promptly and there are large co-benefits in terms of improved air quality. This study is the first to systematically quantify the Arctic climate impact of regional SLCF emissions, taking into account BC, sulphur dioxide (SO2), nitrogen oxides (NOx), volatile hydrocarbons (VOC), organic carbon (OC) and tropospheric ozone, their transport processes and transformations in the atmosphere. Using several chemical transport models we perform detailed radiative forcing calculations from emissions of these species. Geographically we separate emissions into seven source regions that correspond with the national groupings of the Arctic Council, the leading body organizing international policy in the region (the United States, Canada, the Nordic countries, the rest of Europe, Russia, East and South Asia, and the rest of the world). We look at six main sectors known to account for [nearly all] of these emissions: households (domestic), energy/industry/waste, transport, agricultural fires, grass/forest fires, and gas flaring. We find that the largest Arctic warming source is from emissions within the Asian nations. However, the Arctic is most sensitive, per unit mass emitted, to SLCFs emissions from a small number of activities within the Arctic nations themselves. A stringent, but technically feasible SLCFs mitigation scenario, phased in from 2015 through 2030, can cut warming by 0.2 K in 2050.

Response of Arctic Temperature to Changes in Emissions of Short-Lived Climate Forcers

NASA Astrophysics Data System (ADS)

Sand, M.; Berntsen, T.; von Salzen, K.; Flanner, M.; Langner, J.; Victor, D. G.

2014-12-01

There is growing scientific and political interest in the impacts of climate change and anthropogenic emissions on the Arctic. Over recent decades temperatures in the Arctic have increased twice the global rate, largely due to ice albedo and temperature feedbacks. While deep cuts in global CO2 emissions are required to slow this warming, there is also growing interest in the potential for reducing short lived climate forcers (SLCFs). Politically, action on SLCFs may be particularly promising because the benefits of mitigation appear promptly and there are large co-benefits in terms of improved air quality. This study is the first to systematically quantify the Arctic climate impact of regional SLCF emissions, taking into account BC, sulphur dioxide (SO2), nitrogen oxides (NOx), volatile hydrocarbons (VOC), organic carbon (OC) and tropospheric ozone, their transport processes and transformations in the atmosphere. Using several chemical transport models we perform detailed radiative forcing calculations from emissions of these species. Geographically we separate emissions into seven source regions that correspond with the national groupings of the Arctic Council, the leading body organizing international policy in the region (the United States, Canada, the Nordic countries, the rest of Europe, Russia, East and South Asia, and the rest of the world). We look at six main sectors known to account for [nearly all] of these emissions: households (domestic), energy/industry/waste, transport, agricultural fires, grass/forest fires, and gas flaring. We find that the largest Arctic warming source is from emissions within the Asian nations. However, the Arctic is most sensitive, per unit mass emitted, to SLCFs emissions from a small number of activities within the Arctic nations themselves. A stringent, but technically feasible SLCFs mitigation scenario, phased in from 2015 through 2030, can cut warming by 0.2 K in 2050.

The Impact of HIV/AIDS on Children and Young People: Reviewing Research Conducted and Distilling Implications for the Education Sector in Asia. Discussion Paper No. I

ERIC Educational Resources Information Center

Wijngaarden, Jan; Shaeffer, Sheldon

2005-01-01

This discussion paper evaluates the impact of HIV/AIDS on the education sector in the Asia Pacific region. It looks at the impact of the epidemic on children (aged 0-18) focusing on how the presence of HIV/AIDS in the household affects the education sector. Examples are summarized from research papers from inter-governmental agencies including…

78 FR 579 - Magnuson-Stevens Act Provisions; Fisheries Off West Coast States; Pacific Coast Groundfish...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-03

... by the PCGFMP. II. Major Provisions This final rule contains two types of major provisions. The first... fishing sector because different fishing sectors require different types of management to control catch... existing management measures and do not represent a change from current management practices. These types...

Global warming releases microplastic legacy frozen in Arctic Sea ice

NASA Astrophysics Data System (ADS)

Obbard, Rachel W.; Sadri, Saeed; Wong, Ying Qi; Khitun, Alexandra A.; Baker, Ian; Thompson, Richard C.

2014-06-01

When sea ice forms it scavenges and concentrates particulates from the water column, which then become trapped until the ice melts. In recent years, melting has led to record lows in Arctic Sea ice extent, the most recent in September 2012. Global climate models, such as that of Gregory et al. (2002), suggest that the decline in Arctic Sea ice volume (3.4% per decade) will actually exceed the decline in sea ice extent, something that Laxon et al. (2013) have shown supported by satellite data. The extent to which melting ice could release anthropogenic particulates back to the open ocean has not yet been examined. Here we show that Arctic Sea ice from remote locations contains concentrations of microplastics at least two orders of magnitude greater than those that have been previously reported in highly contaminated surface waters, such as those of the Pacific Gyre. Our findings indicate that microplastics have accumulated far from population centers and that polar sea ice represents a major historic global sink of man-made particulates. The potential for substantial quantities of legacy microplastic contamination to be released to the ocean as the ice melts therefore needs to be evaluated, as do the physical and toxicological effects of plastics on marine life.

Low levels of hybridization between sympatric Arctic char (Salvelinus alpinus) and Dolly Varden char (Salvelinus malma) highlights their genetic distinctiveness and ecological segregation.

PubMed

May-McNally, Shannan L; Quinn, Thomas P; Taylor, Eric B

2015-08-01

Understanding the extent of interspecific hybridization and how ecological segregation may influence hybridization requires comprehensively sampling different habitats over a range of life history stages. Arctic char (Salvelinus alpinus) and Dolly Varden (S. malma) are recently diverged salmonid fishes that come into contact in several areas of the North Pacific where they occasionally hybridize. To better quantify the degree of hybridization and ecological segregation between these taxa, we sampled over 700 fish from multiple lake (littoral and profundal) and stream sites in two large, interconnected southwestern Alaskan lakes. Individuals were genotyped at 12 microsatellite markers, and genetic admixture (Q) values generated through Bayesian-based clustering revealed hybridization levels generally lower than reported in a previous study (<0.6% to 5% of samples classified as late-generation hybrids). Dolly Varden and Arctic char tended to make different use of stream habitats with the latter apparently abandoning streams for lake habitats after 2-3 years of age. Our results support the distinct biological species status of Dolly Varden and Arctic char and suggest that ecological segregation may be an important factor limiting opportunities for hybridization and/or the ecological performance of hybrid char.

Low levels of hybridization between sympatric Arctic char (Salvelinus alpinus) and Dolly Varden char (Salvelinus malma) highlights their genetic distinctiveness and ecological segregation

PubMed Central

May-McNally, Shannan L; Quinn, Thomas P; Taylor, Eric B

2015-01-01

Understanding the extent of interspecific hybridization and how ecological segregation may influence hybridization requires comprehensively sampling different habitats over a range of life history stages. Arctic char (Salvelinus alpinus) and Dolly Varden (S. malma) are recently diverged salmonid fishes that come into contact in several areas of the North Pacific where they occasionally hybridize. To better quantify the degree of hybridization and ecological segregation between these taxa, we sampled over 700 fish from multiple lake (littoral and profundal) and stream sites in two large, interconnected southwestern Alaskan lakes. Individuals were genotyped at 12 microsatellite markers, and genetic admixture (Q) values generated through Bayesian-based clustering revealed hybridization levels generally lower than reported in a previous study (<0.6% to 5% of samples classified as late-generation hybrids). Dolly Varden and Arctic char tended to make different use of stream habitats with the latter apparently abandoning streams for lake habitats after 2–3 years of age. Our results support the distinct biological species status of Dolly Varden and Arctic char and suggest that ecological segregation may be an important factor limiting opportunities for hybridization and/or the ecological performance of hybrid char. PMID:26356310

Diversity of Arctic Pelagic Prokaryotes with an emphasis on photoheterotrophic bacteria: a review

NASA Astrophysics Data System (ADS)

Boeuf, D.; Humily, F.; Jeanthon, C.

2014-02-01

The Arctic Ocean is a unique marine environment with respect to seasonality of light, temperature, perennial ice cover and strong stratification. Other important distinctive features are the influence of extensive continental shelves and its interactions with Atlantic and Pacific water masses and freshwater from sea ice melt and rivers. These characteristics have major influence on the biological and biogeochemical processes occurring in this complex natural system. Heterotrophic bacteria are crucial components of marine food webs and have key roles in controlling carbon fluxes in the oceans. Although it was previously thought that these organisms relied on the organic carbon in seawater for all of their energy needs, several recent discoveries now suggest that pelagic bacteria can depart from a strictly heterotrophic lifestyle by obtaining energy through unconventional mechanisms that are linked to the penetration of sunlight into surface waters. These photoheterotrophic mechanisms may play a significant role in the energy budget in the euphotic zone of marine environments. We can suspect that this role could be of greater importance in the Arctic Ocean where environmental changes triggered by climate change could favor the photoheterotrophic lifestyle. Here we review advances in our knowledge of the diversity of marine photoheterotrophic bacteria and discuss their significance in the Arctic Ocean gained in the framework of the Malina cruise.

Continuous pCO2 time series from Ocean Networks Canada cabled observatories at the northeast Pacific shelf edge and in the sub-tidal Arctic

NASA Astrophysics Data System (ADS)

Juniper, S. Kim; Sastri, Akash; Mihaly, Steven; Duke, Patrick; Else, Brent; Thomas, Helmuth; Miller, Lisa

2017-04-01

Marine pCO2 sensor technology has progressed to the point where months-long time series from remotely-deployed pCO2 sensors can be used to document seasonal and higher frequency variability in pCO2 and its relationship to oceanographic processes. Ocean Networks Canada recently deployed pCO2 sensors on two cabled platforms: a bottom-moored (400 m depth), vertical profiler at the edge of the northeast Pacific continental shelf off Vancouver Island, Canada, and a subtidal seafloor platform in the Canadian High Arctic (69˚ N) at Cambridge Bay, Nunavut. Both platforms streamed continuous data to a shore-based archive from Pro-Oceanus pCO2 sensors and other oceanographic instruments. The vertical profiler time series revealed substantial intrusions of corrosive (high CO2/low O2), saltier, colder water masses during the summertime upwelling season and during winter-time reversals of along-slope currents. Step-wise profiles during the downcast provided the most reliable pCO2 data, permitting the sensor to equilibrate to the broad range of pCO2 concentrations encountered over the 400 metre depth interval. The Arctic pCO2 sensor was deployed in August 2015. Reversing seasonal trends in pCO2 and dissolved oxygen values can be related to the changing balance of photosynthesis and respiration under sea ice, as influenced by irradiance. Correlation of pCO2 and dissolved oxygen sensor data and the collection of calibration samples have permitted evaluation of sensor performance in relation to operational conditions encountered in vertical profiling and lengthy exposure to subzero seawater.

Predictability and prediction of the total number of winter extremely cold days over China

NASA Astrophysics Data System (ADS)

Luo, Xiao; Wang, Bin

2018-03-01

The current dynamical climate models have limited skills in predicting winter temperature in China. The present study uses physics-based empirical models (PEMs) to explore the sources and limits of the seasonal predictability in the total number of extremely cold days (NECD) over China. A combined cluster-rotated EOF analysis reveals two sub-regions of homogeneous variability among hundreds of stations, namely the Northeast China (NE) and Main China (MC). This reduces the large-number of predictands to only two indices, the NCED-NE and NCED-MC, which facilitates detection of the common sources of predictability for all stations. The circulation anomalies associated with the NECD-NE exhibit a zonally symmetric Arctic Oscillation-like pattern, whereas those associated with the NECD-MC feature a North-South dipolar pattern over Asia. The predictability of the NECD originates from SST and snow cover anomalies in the preceding September and October. However, the two regions have different SST predictors: The NE predictor is in the western Eurasian Arctic while the MC predictor is over the tropical-North Pacific. The October snow cover predictors also differ: The NE predictor primarily resides in the central Eurasia while the MC predictor is over the western and eastern Eurasia. The PEM prediction results suggest that about 60% (55%) of the total variance of winter NECD over the NE (Main) China are likely predictable 1 month in advance. The NECD at each station can also be predicted by using the four predictors that were detected for the two indices. The cross-validated temporal correlation skills exceed 0.70 at most stations. The physical mechanisms by which the autumn Arctic sea ice, snow cover, and tropical-North Pacific SST anomalies affect winter NECD over the NE and Main China are discussed.

Distribution and air-sea exchange of current-use pesticides (CUPs) from East Asia to the high Arctic Ocean.

PubMed

Zhong, Guangcai; Xie, Zhiyong; Cai, Minghong; Möller, Axel; Sturm, Renate; Tang, Jianhui; Zhang, Gan; He, Jianfeng; Ebinghaus, Ralf

2012-01-03

Surface seawater and marine boundary layer air samples were collected on the ice-breaker R/V Xuelong (Snow Dragon) from the East China Sea to the high Arctic (33.23-84.5° N) in July to September 2010 and have been analyzed for six current-use pesticides (CUPs): trifluralin, endosulfan, chlorothalonil, chlorpyrifos, dacthal, and dicofol. In all oceanic air samples, the six CUPs were detected, showing highest level (>100 pg/m(3)) in the Sea of Japan. Gaseous CUPs basically decreased from East Asia (between 36.6 and 45.1° N) toward Bering and Chukchi Seas. The dissolved CUPs in ocean water ranged widely from

Sea Ice Evolution in the Pacific Arctic by Selected CMIP5 Models: the Present and the Future

NASA Astrophysics Data System (ADS)

Wang, M.; Yang, Q.; Overland, J. E.; Stabeno, P. J.

2016-12-01

With fast declining of sea ice cover in the Arctic, the timing of sea ice break-up and freeze-up is an urgent economic, social and scientific issue. Based on daily sea ice concentration data we assess three parameters: the dates of sea ice break-up and freeze-up and the annual sea ice duration in the Pacific Arctic. The sea ice duration is shrinking, with the largest trend during the past decade (1990-2015); this declining trend will continue based on CMIP5 model projections. The seven CMIP5 models used in current study are able to simulate all three parameters well when compared with observations. Comparisons made at eight Chukchi Sea mooring sites and the eight Distributed Biological Observatory (DBO) boxes show consistent results as well. The 30-year averaged trend for annual sea ice duration is projected to be -0.68 days/year to -1.2 days/year for 2015-2044. This is equivalent 20 to 36 days reduction in the annual sea ice duration. A similar magnitude of the negative trend is also found at all eight DBO boxes. The reduction in annual sea ice duration will include both earlier break-up dates and later freeze-up date. However, models project that a later freeze-up contributes more than early break-up to the overall shortening of annual sea ice duration. Around the Bering Strait future changes are the smallest, with less than 20-days change in duration during next 30 years. Upto 60 days reduction of the sea ice duration is projected for the decade of 2030-2044 in the East Siberia, the Chukchi and the Beaufort Seas.

ICESCAPE Optical Insturments

NASA Image and Video Library

2017-12-08

On July 6, 2011, ICESCAPE scientists lowered optical instruments through a hole at the bottom of a melt pond, to study the waters underneath the ice. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

A Linkage of Recent Arctic Summer Sea Ice and Snowfall Variability of Japan

NASA Astrophysics Data System (ADS)

Iwamoto, K.; Honda, M.; Ukita, J.

2014-12-01

In spite of its mid-latitude location, Japan has a markedly high amount of snowfall, which owes much to the presence of cold air-break from Siberia and thus depends on the strength of the Siberian high and the Aleutian low. With this background this study examines the relationship between interannual variability and spatial patterns of snowfall in Japan with large-scale atmospheric and sea ice variations. The lag regression map of the winter snowfall in Japan on the time series of the Arctic SIE from the preceding summer shows a seesaw pattern in the snowfall, suggesting an Arctic teleconnection to regional weather. From the EOF analyses conducted on the snowfall distribution in Japan, we identify two modes with physical significance. The NH SIC and SLP regressed on PC1 show a sea ice reduction in the Barents and Kara Seas and anomalous strength of the Siberia high as discussed in Honda et al. (2009) and other studies, which support the above notion that the snowfall variability of Japan is influenced by Arctic sea ice conditions. Another mode is related to the AO/NAO and the hemispheric scale double sea-ice seesaw centered over the sub-Arctic region: one between the Labrador and Nordic Seas in the Atlantic and the other between the Okhotsk and Bering Seas from the Pacific as discussed in Ukita et al. (2007). Together, observations point to a significant role of the sea-ice in determining mid-latitude regional climate and weather patterns.

Optical properties of melting first-year Arctic sea ice

NASA Astrophysics Data System (ADS)

Light, Bonnie; Perovich, Donald K.; Webster, Melinda A.; Polashenski, Christopher; Dadic, Ruzica

2015-11-01

The albedo and transmittance of melting, first-year Arctic sea ice were measured during two cruises of the Impacts of Climate on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) project during the summers of 2010 and 2011. Spectral measurements were made for both bare and ponded ice types at a total of 19 ice stations in the Chukchi and Beaufort Seas. These data, along with irradiance profiles taken within boreholes, laboratory measurements of the optical properties of core samples, ice physical property observations, and radiative transfer model simulations are employed to describe representative optical properties for melting first-year Arctic sea ice. Ponded ice was found to transmit roughly 4.4 times more total energy into the ocean, relative to nearby bare ice. The ubiquitous surface-scattering layer and drained layer present on bare, melting sea ice are responsible for its relatively high albedo and relatively low transmittance. Light transmittance through ponded ice depends on the physical thickness of the ice and the magnitude of the scattering coefficient in the ice interior. Bare ice reflects nearly three-quarters of the incident sunlight, enhancing its resiliency to absorption by solar insolation. In contrast, ponded ice absorbs or transmits to the ocean more than three-quarters of the incident sunlight. Characterization of the heat balance of a summertime ice cover is largely dictated by its pond coverage, and light transmittance through ponded ice shows strong contrast between first-year and multiyear Arctic ice covers.

Integrated Arctic Observation System Development Under Horizon 2020

NASA Astrophysics Data System (ADS)

Sandven, S.

2016-12-01

The overall objective of INTAROS is to develop an integrated Arctic Observation System (iAOS) by extending, improving and unifying existing systems in the different regions of the Arctic. INTAROS will have a strong multidisciplinary focus, with tools for integration of data from atmosphere, ocean, cryosphere and terrestrial sciences, provided by institutions in Europe, North America and Asia. Satellite earth observation data plays an increasingly important role in such observing systems, because the amount of EO data for observing the global climate and environment grows year by year. In situ observing systems are much more limited due to logistical constraints and cost limitations. The sparseness of in situ data is therefore the largest gap in the overall observing system. INTAROS will assess strengths and weaknesses of existing observing systems and contribute with innovative solutions to fill some of the critical gaps in the in situ observing network. INTAROS will develop a platform, iAOS, to search for and access data from distributed databases. The evolution into a sustainable Arctic observing system requires coordination, mobilization and cooperation between the existing European and international infrastructures (in-situ and remote including space-based), the modeling communities and relevant stakeholder groups. INTAROS will include development of community-based observing systems, where local knowledge is merged with scientific data. An integrated Arctic Observation System will enable better-informed decisions and better-documented processes within key sectors (e.g. local communities, shipping, tourism, fishing), in order to strengthen the societal and economic role of the Arctic region and support the EU strategy for the Arctic and related maritime and environmental policies.

Philinidae, Laonidae and Philinorbidae (Gastropoda: Cephalaspidea: Philinoidea) from the northeastern Pacific Ocean and the Beaufort Sea (Arctic Ocean).

PubMed

Valdés, Ángel; Cadien, Donald B; Gosliner, Terrence M

2016-08-08

Based on morphological data a total of nine native species of Philinidae are recognized from the northeastern Pacific including the Bering Sea and the adjacent Arctic Ocean (Beaufort Sea). Four of them have been previously described: Philine ornatissima Yokoyama, 1927, Philine bakeri Dall, 1919, Philine polystrigma (Dall, 1908), and Philine hemphilli Dall, 1919. Five of them are new and described herein: Philine mcleani sp. nov., Philine baxteri sp. nov., Philine malaquiasi sp. nov., Philine wareni sp. nov., and Philine harrisae sp. nov. These species display a substantial degree of variation in internal and external morphological traits (i.e., presence/absence of gizzard plates, different radular structure and tooth morphology, various reproductive anatomical features) and it is likely that they belong to different clades (genera). However, in the absence of a comprehensive phylogeny for Philine, they are here provisionally regarded as Philine sensu lato. In addition to the nine native species, two introduced species: Philine orientalis A. Adams, 1854 and Philine auriformis Suter, 1909 are here illustrated and compared to the native species to facilitate identification. Finally, two species previously considered members of Philinidae are examined anatomically and confirmed as members of Laonidae, Laona californica (Willett, 1944) and Philinorbidae, Philinorbis albus (Mattox, 1958), based on morphological data.

Eocene climate and Arctic paleobathymetry: A tectonic sensitivity study using GISS ModelE-R

NASA Astrophysics Data System (ADS)

Roberts, C. D.; Legrande, A. N.; Tripati, A. K.

2009-12-01

The early Paleogene (65-45 million years ago, Ma) was a ‘greenhouse’ interval with global temperatures warmer than any other time in the last 65 Ma. This period was characterized by high levels of CO2, warm high-latitudes, warm surface-and-deep oceans, and an intensified hydrological cycle. Sediments from the Arctic suggest that the Eocene surface Arctic Ocean was warm, brackish, and episodically enabled the freshwater fern Azolla to bloom. The precise mechanisms responsible for the development of these conditions remain uncertain. We present equilibrium climate conditions derived from a fully-coupled, water-isotope enabled, general circulation model (GISS ModelE-R) configured for the early Eocene. We also present model-data comparison plots for key climatic variables (SST and δ18O) and analyses of the leading modes of variability in the tropical Pacific and North Atlantic regions. Our tectonic sensitivity study indicates that Northern Hemisphere climate would have been very sensitive to the degree of oceanic exchange through the seaways connecting the Arctic to the Atlantic and Tethys. By restricting these seaways, we simulate freshening of the surface Arctic Ocean to ~6 psu and warming of sea-surface temperatures by 2°C in the North Atlantic and 5-10°C in the Labrador Sea. Our results may help explain the occurrence of low-salinity tolerant taxa in the Arctic Ocean during the Eocene and provide a mechanism for enhanced warmth in the north western Atlantic. We also suggest that the formation of a volcanic land-bridge between Greenland and Europe could have caused increased ocean convection and warming of intermediate waters in the Atlantic. If true, this result is consistent with the theory that bathymetry changes may have caused thermal destabilisation of methane clathrates in the Atlantic.

The Holocene history of Nares Strait: Transition from glacial bay to Arctic-Atlantic throughflow

USGS Publications Warehouse

Jennings, Anne E.; Sheldon, Christina; Cronin, Thomas M.; Francus, Pierre; Stoner, Joseph; Andrews, John

2011-01-01

Retreat of glacier ice from Nares Strait and other straits in the Canadian Arctic Archipelago after the end of the last Ice Age initiated an important connection between the Arctic and the North Atlantic Oceans, allowing development of modern ocean circulation in Baffin Bay and the Labrador Sea. As low-salinity, nutrient-rich Arctic Water began to enter Baffin Bay, it contributed to the Baffin and Labrador currents flowing southward. This enhanced freshwater inflow must have influenced the sea ice regime and likely is responsible for poor calcium carbonate preservation that characterizes the Baffin Island margin today. Sedimentologic and paleoceanographic data from radiocarbon-dated core HLY03-05GC, Hall Basin, northern Nares Strait, document the timing and paleoenvironments surrounding the retreat of waning ice sheets from Nares Strait and opening of this connection between the Arctic Ocean and Baffin Bay. Hall Basin was deglaciated soon before 10,300 cal BP (calibrated years before present) and records ice-distal sedimentation in a glacial bay facing the Arctic Ocean until about 9,000 cal BP. Atlantic Water was present in Hall Basin during deglaciation, suggesting that it may have promoted ice retreat. A transitional unit with high ice-rafted debris content records the opening of Nares Strait at approximately 9,000 cal BP. High productivity in Hall Basin between 9,000 and 6,000 cal BP reflects reduced sea ice cover and duration as well as throughflow of nutrient-rich Pacific Water. The later Holocene is poorly resolved in the core, but slow sedimentation rates and heavier carbon isotope values support an interpretation of increased sea ice cover and decreased productivity during the Neoglacial period.

NSF-supported education/outreach program takes young researchers to the Arctic

NASA Astrophysics Data System (ADS)

Alexeev, V. A.; Walsh, J. E.; Hock, R.; Kaden, U.; Euskirchen, E. S.; Kholodov, A. L.; Bret-Harte, M. S.; Sparrow, E. B.

2015-12-01

Today, more than ever, an integrated cross-disciplinary approach is necessary to explain changes in the Arctic and understand their implications for the human environment. Advanced training and active involvement of early-career scientists is an important component of this cross-disciplinary approach. This effort led by the International Arctic Research Center at the University of Alaska Fairbanks (UAF) started in 2003. The newly supported project in 2013 is planning four summer schools (one per year) focused on four themes in four different Arctic locations. It provides the participants with an interdisciplinary perspective on Arctic change and its impacts on diverse sectors of the North. It is linked to other ongoing long-term observational and educational programs (e.g. NABOS, Nansen and Amundsen Basins Observational System; LTER, Long Term Environmental Research) and targets young scientists by using the interdisciplinary and place-based setting to broaden their perspective on Arctic change and to enhance their communication skills. Each course for 15-20 people consists of classroom and hands-on components and work with a multidisciplinary group of mentors on projects devoted to themes exemplified by the location. A specialist from the School of Education at UAF evaluates student's progress during the summer schools. Lessons learned during the 12 years of conducting summer schools, methods of attracting in-kind support and approaches to teaching students are prominently featured in this study. Activities during the most recent school, conducted in Fairbanks and LTER Toolik Lake Field Station in 2015 are the focus of this presentation.

Shrub growth and expansion in the Arctic tundra: an assessment of controlling factors using an evidence-based approach

NASA Astrophysics Data System (ADS)

Martin, Andrew C.; Jeffers, Elizabeth S.; Petrokofsky, Gillian; Myers-Smith, Isla; Macias-Fauria, Marc

2017-08-01

Woody shrubs have increased in biomass and expanded into new areas throughout the Pan-Arctic tundra biome in recent decades, which has been linked to a biome-wide observed increase in productivity. Experimental, observational, and socio-ecological research suggests that air temperature—and to a lesser degree precipitation—trends have been the predominant drivers of this change. However, a progressive decoupling of these drivers from Arctic vegetation productivity has been reported, and since 2010, vegetation productivity has also been declining. We created a protocol to (a) identify the suite of controls that may be operating on shrub growth and expansion, and (b) characterise the evidence base for controls on Arctic shrub growth and expansion. We found evidence for a suite of 23 proximal controls that operate directly on shrub growth and expansion; the evidence base focused predominantly on just four controls (air temperature, soil moisture, herbivory, and snow dynamics). 65% of evidence was generated in the warmest tundra climes, while 24% was from only one of 28 floristic sectors. Temporal limitations beyond 10 years existed for most controls, while the use of space-for-time approaches was high, with 14% of the evidence derived via experimental approaches. The findings suggest the current evidence base is not sufficiently robust or comprehensive at present to answer key questions of Pan-Arctic shrub change. We suggest future directions that could strengthen the evidence, and lead to an understanding of the key mechanisms driving changes in Arctic shrub environments.

Using an Environmental Intelligence Framework to Evaluate the Impacts of Ocean Acidification in the Arctic

NASA Astrophysics Data System (ADS)

Mathis, J. T.; Baskin, M.; Cross, J.

2016-12-01

The highly productive coastal seas of the Arctic Ocean are located in areas that are projected to experience strong global change, including rapid transitions in temperature and ocean acidification-driven changes in pH and other chemical parameters. Many of the marine organisms that may be most intensely affected by ocean acidification (OA) and other environmental stressors contribute substantially to the commercial fisheries of the Bering Sea and traditional subsistence food supplies across the Arctic. This could represent a looming challenge in many communities as the average prevalence of household food insecurity and very low food security in Alaska are already 12 percent and 4.3 percent, respectively. Here, we evaluate the patterns of dependence on marine resources within Alaska's Arctic that could be negatively impacted by OA and current community characteristics to assess the potential risk to the fishery sector from OA. We used a risk assessment framework to analyze an earth-system global model of ocean chemistry, fisheries harvest data, and demographic information. The analysis showed that regions around Alaska vary in their vulnerability to OA, but that each one will have to deal with possible impacts. Therefore, OA merits consideration in policy planning, as it may represent another challenge to Alaskan communities, some of which are already under acute socio-economic strains. With this in mind, we will present a number of adaptation strategies for communities living throughout Alaska's Arctic that could be applicable to other Arctic regions.

Measurement of Arctic sea-ice thickness by submarine 5 years after SCICEX

NASA Astrophysics Data System (ADS)

Hughes, Nicholas E.; Wadhams, Peter

In April 2004 the Royal Navy submarine HMS Tireless became the first UK submarine to conduct environmental monitoring in the Arctic Ocean since 1996. As the last US SCICEX (Scientific Ice Expeditions) cruise was in 2000, this has been the only opportunity for a civilian scientist to carry out measurement of ice draft and oceanography over a wide area of the Arctic. This paper presents preliminary results and compares them with similar investigations in the 1970s-90s. The route of Tireless covered a large area of the European sector of the Arctic from 5° E to 62° W. Transects were carried out from the marginal ice zone in Fram Strait up to the North Pole and along the 85° N parallel north of Greenland. As part of work for the European Commission IRIS project, image intensity from the advanced synthetic aperture radar instrument on the European Space Agency's Envisat satellite has been compared with ice draft from the submarine. The raw data were found to be highly variable, so a moving average was applied, producing a correlation of 0.79. Tireless carried a full oceanographic sensor suite and expendable probes for investigation into changes in the Arctic Ocean. The results from these show further erosion of the Arctic cold halocline layer by advancing Atlantic Water compared to previous climatologies and fieldwork expeditions. Preliminary ice-draft data from 85° N show deeper ice keels than those encountered by a submarine on the same route in 1987.

Russian Artic Strategy: Or How I Learned to Stop Worrying and Love Bureaucratic Politics

DTIC Science & Technology

a land grab, during both periods Russia has pursued an economic calculation strategy, attempting to maintain a benign political environment while at...the same time steering the Arctic energy and transport sectors for the purpose of reaping economic rewards. The continuity noted in Russias strategy is

Status and Impacts of Arctic Freshwater Export

NASA Astrophysics Data System (ADS)

Haine, T. W. N.

2017-12-01

Large freshwater anomalies clearly exist in the Arctic Ocean. For example, liquid freshwater has accumulated in the Beaufort Gyre in the decade of the 2000s compared to 1980-2000, with an extra ≈5000 km3—about 25%—being stored. The sources of freshwater to the Arctic from precipitation and runoff have increased between these periods (most of the evidence comes from models). Despite flux increases from 2001 to 2011, it is uncertain if the marine freshwater source through Bering Strait for the 2000s has changed, as observations in the 1980s and 1990s are incomplete. The marine freshwater fluxes draining the Arctic through Fram and Davis straits are also insignificantly different. In this way, the balance of sources and sinks of freshwater to the Arctic, Canadian Arctic Archipelago (CAA), and Baffin Bay shifted to about 1200±730 km3yr-1 freshening the region, on average, during the 2000s. The observed accumulation of liquid freshwater is consistent with this increased supply and the loss of freshwater from sea ice (Figure, right). Evidence exists that such discharges can impact the Atlantic meridional overturning circulation, and hence Atlantic sector climate. Nevertheless, it appears that the observed AMOC variability since 2004, when high quality measurements began, is not attributable to anthropogenic influence. This work is based on, and updated from, Haine et al. (2015), Carmack et al. (2016), and Haine (2016). Haine, T. W. N. Ocean science: Vagaries of Atlantic overturning. Nature Geoscience, 9, 479-480, 10.1038/ngeo2748, 2016. T. W. N. Haine et al., Arctic Freshwater Export: Status, Mechanisms, and Prospects, Global Planetary Change, 125, 13-35, 10.1016/j.glopacha.2014.11.013, 2015. E. Carmack et al., Fresh water and its role in the Arctic Marine System: sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans. J. G. Res. Biogeosciences, 10.1002/2015JG003140, 2016.

Scientific Discoveries in the Central Arctic Ocean Based on Seafloor Mapping Carried out to Support Article 76 Extended Continental Shelf Claims (Invited)

NASA Astrophysics Data System (ADS)

Jakobsson, M.; Mayer, L. A.; Marcussen, C.

2013-12-01

Despite the last decades of diminishing sea-ice cover in the Arctic Ocean, ship operations are only possible in vast sectors of the central Arctic using the most capable polar-class icebreakers. There are less than a handful of these icebreakers outfitted with modern seafloor mapping equipment. This implies either fierce competition between those having an interest in using these icebreakers for investigations of the shape and properties of Arctic Ocean seafloor or, preferably, collaboration. In this presentation examples will be shown of scientific discoveries based on mapping data collected during Arctic Ocean icebreaker expeditions carried out for the purpose of substantiating claims for an extended continental shelf under United Nations Convention of the Law of the Sea (UNCLOS) Article 76. Scientific results will be presented from the suite of Lomonosov Ridge off Greenland (LOMROG) expeditions (2007, 2009, and 2012), shedding new light on Arctic Ocean oceanography and glacial history. The Swedish icebreaker Oden was used in collaboration between Sweden and Denmark during LOMROG to map and sample portions of the central Arctic Ocean; specifically focused on the Lomonosov Ridge north of Greenland. While the main objective of the Danish participation was seafloor and sub-seabed mapping to substantiate their Article 76 claim, LOMROG also included several scientific components, with scientists from both countries involved. Other examples to be presented are based on data collected using US Coast Guard Cutter Healy, which for several years has carried out mapping in the western Arctic Ocean for the US continental shelf program. All bathymetric data collected with Oden and Healy have been contributed to the International Bathymetric Chart of the Arctic Ocean (IBCAO). This is also the case for bathymetric data collected by Canadian Coast Guard Ship Louis S. St-Laurent for Canada's extended continental shelf claim. Together, the bathymetric data collected during these Article 76 mapping missions comprises, by far, the most comprehensive contribution to the last Version 3.0 of IBCAO.

Salmon on the Edge: Growth and Condition of Juvenile Chum and Pink Salmon in the Northeastern Bering Sea

NASA Astrophysics Data System (ADS)

McPhee, M. V.

2016-02-01

As the Arctic and Subarctic regions warm, Pacific salmon (Oncorhynchus spp.) are expected to expand their range northward during ice-free periods in the Bering and Chukchi seas. The oscillating control hypothesis, which describes energetic differences of primary consumers between ice-associated and pelagic production phases, provides a framework for understanding how juvenile salmon might respond to changing conditions at the northern edge of their marine range. Additionally, relationships between growth/condition and temperature, salinity and bottom depth will help identify marine habitats supporting growth at the Arctic-Subarctic interface. In this study, we used survey data from NOAA and Arctic Ecosystem Integrated Survey project to 1) compare growth and condition of juvenile pink (O. gorbuscha) and chum (O. keta) salmon in the NE Bering Sea between warm and cool spring phases, and 2) describe relationships between summer environmental conditions and juvenile salmon growth and condition from 2006 - 2010. Chum and pink salmon were shorter, and chum salmon exhibited greater energy density, in years with cool springs; however, no other aspects of size and condition differed significantly between phases. Over all years, longer and more energy dense individuals of both species were caught at stations with greater bottom depths and in cooler sea-surface temperatures. We found little evidence that chlorophyll-a explained much of the variation in size or condition. We used insulin-like growth factor-1 (IGF-1) concentration as an indicator of relative growth rate for fishes sampled in 2009-2012 and that found juvenile salmon exhibited higher IGF-1 concentrations in 2010-2012 than in 2009. IGF-1 concentrations tended to increase with SST in chum salmon and with bottom depth (a proxy for distance from shore) in pink salmon, but more years of data are needed to adequately describe the relationship of IGF with environmental conditions. This study, although descriptive in nature, provides a starting point for developing a mechanistic understanding of how Pacific salmon will respond to warming at the Arctic-Subarctic interface.

Tracing the source of deep water in the Arctic Ocean with 17Oexcess of dissolved O2

NASA Astrophysics Data System (ADS)

Smethie, W. M., Jr.; Luz, B.; Barkan, E.; Broecker, W. S.

2014-12-01

The 17Oexcess of dissolved O2 (17Δ) in the ocean is a unique property which is useful for telling apart O2 produced by marine photosynthesis (bio-O2) from atmospheric O2. Unlike O2 concentration, 17Δ is not affected by respiration and thus behaves conservatively in the deep sea. In general, 17Δ in the oceanic mixed layer is low due to the dominance of air-sea gas exchange. In contrast, in the Arctic mixed-layer 17Δ is higher because sufficient light penetrates through the sea-ice cover and drives photosynthesis, but air-sea gas exchange is retarded by sea ice cover. We have preliminary 17Δ data from depth profiles in the Eurasian and Makarov basins. In both, the fraction of bio-O2 is about 20 % in the surface mixed layer. However, the vertical distribution beneath the mixed layer at the two stations is substantially different. In the Makarov Basin there is a layer of Pacific Water centered at about 100 m, which enters the Arctic Ocean through Bering Strait and is modified as it flows across the wide Chukchi and Siberian shelves. It has a strong maximum in 17Δ, equivalent to ~30% bio-O2. 17Δ then decreases through the underlying halocline to a minimum between 500 and 700 m, which lies within the Barents Sea Branch of Atlantic Water (BSBW) indicating ~15% bio-O2. At the Eurasian Basin station, 17Δ decreases from the mixed layer through the halocline reaching a minimum at the temperature maximum of Atlantic Water. This temperature maximum marks the core of the Fram Strait Branch of Atlantic Water (FSBW). 17Δ then increases to a maximum indicating ~20% bio-O2 between 500 and 700 m. The BSBW is produced as Atlantic Water flows through the shallow Barents Sea becoming denser than FSBW and enters the Eurasian Basin through the Santa Anna Trough beneath the FSBW. Our 17Δ measurements suggest that waters of Pacific and Atlantic origin that transit across the wide Arctic continental shelves acquire a high 17Δ signal indicative of photosynthesis in ice covered water.

Perfluoroalkyl acids in surface seawater from the North Pacific to the Arctic Ocean: Contamination, distribution and transportation.

PubMed

Li, Lei; Zheng, Hongyuan; Wang, Tieyu; Cai, Minghong; Wang, Pei

2018-03-16

The bioaccumulative, persistent and toxic properties of long-chain perfluoroalkyl acids (PFAAs) resulted in strict regulations on PFAAs, especially in developed countries. Consequently, the industry manufacturing of PFAAs shifts from long-chain to short-chain. In order to better understand the pollution situation of PFAAs in marine environment under this new circumstance, the occurrence of 17 linear PFAAs was investigated in 30 surface seawater samples from the North Pacific to Arctic Ocean (123°E to 24°W, 32 to 82°N) during the sixth Chinese Arctic Expedition in 2014. Total concentrations of PFAAs (∑PFAAs) were between 346.9 pg per liter (pg/L) to 3045.3 pg/L. The average concentrations of ∑PFAAs decreased in the order of East China Sea (2791.4 pg/L, n = 2), Sea of Japan (East Sea) (832.8 pg/L, n = 6), Arctic Ocean (516.9 pg/L, n = 7), Chukchi Sea (505.2 pg/L, n = 4), Bering Sea (501.2 pg/L, n = 8) and Sea of Okhotsk (417.7 pg/L, n = 3). C4 to C9 perfluoroalkyl carboxylic acids (PFCAs) were detected in more than 80% of the surface water samples. Perfluorobutanoic acid (PFBA) was the most prevalent compound and perfluorooctanoic acid (PFOA) was the second abundant homolog. The concentration of individual PFAAs in the surface seawater of East China Sea was much higher than other sampling seas. As the spatial distribution of PFAAs in the marine environment was mainly influenced by the river inflow from the basin countries, which proved the large input from China. Furthermore, the marginal seas of China were found with the greatest burden of PFOA comparing the pollution level in surface seawater worldwide. PFBA concentration in the surrounding seas of China was also high, but distributed more evenly with an obvious increase in recent years. This large-scale monitoring survey will help the improvement and development of PFAAs regulations and management, where production shift should be taken into consideration. Copyright © 2018 Elsevier Ltd. All rights reserved.

Snow in Time for the Solstice

NASA Technical Reports Server (NTRS)

2004-01-01

In mid-December, the weather in eastern North America cooperated with the calendar, and a wintry blast from the Arctic delivered freezing cold air, blustery winds, and snow just in time for the Winter Solstice on December 21' the Northern Hemisphere's longest night of the year and the official start of winter. This image was captured by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on December 20, 2004, the day after an Arctic storm dove down into the United States, bringing snow to New England (upper right of top image); the coastal mid-Atlantic, including Washington, D.C.; and the southern Appalachian Mountains in Tennessee and North Carolina. Over the Atlantic Ocean (image right), the fierce Arctic winds were raking the clouds into rows, like a gardener getting ready to plant the seeds of winter. The detailed close-up at the bottom of this image pair shows the cloud and snow patterns around Lake Ontario, illustrating the occurrence of 'lake-effect snow.' Areas in western upstate New York often get as much as fifteen feet or more of snow each year as cold air from Canada and the Arctic sweeps down over the relatively warm waters of Lakes Ontario and Erie. Cold air plus moisture from the lakes equals heavy snow. Since the wind generally blows from west to east, it is the 'downwind' cities like Buffalo and Rochester that receive the heaping helpings of snowfall, while cities on the upwind side of the lake, such as Toronto, receive much less. Unlike storms that begin with specific low-pressure systems in the Pacific Ocean and march eastward across the Pacific Northwest, the Rockies, the Great Plains, and sometimes the East, the lake-effect snows aren't tied to a specific atmospheric disturbance. They are more a function of geography, which means that the lakes can keep fueling snow storms for as long as they remain ice-free in early winter, as well as when they begin to thaw in late winter and early spring. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE.

50 CFR 660.131 - Pacific whiting fishery management measures.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., surimi (fish paste with additives), fillets (meat from the side of the fish, behind the head and in front... measures. (a) Sectors. In order for a vessel to fish in a particular whiting fishery sector after May 11... considered to be a catcher/processor nor is it considered to be processing fish. Such a vessel is considered...

U.S. Geological Survey (USGS) Western Region: Seabirds Coastal and Ocean Science

USGS Publications Warehouse

Kinsinger, Anne E.

2009-01-01

From the cold, high Arctic area of Alaska to the warm, tropical Pacific area of Hawai'i, a diverse array of seabird species numbering in the millions of individuals live off the bounty of the Pacific Ocean. Many come to land only to nest and raise their young - these are species supremely adapted for life on the water, whether it be near the coast or hundreds of miles at sea. Those seabirds that reside in the North Pacific year-round are joined each summer by millions of migrant birds that leave the southern hemisphere in winter for better feeding conditions in the north. Seabirds in the Pacific remain one of the great wildlife spectacles on the earth. Yet, seabirds face a number of threats such as oil spills, introduction of predators to their nesting islands, and conflicts with fisheries. State and Federal agencies require increasingly sophisticated information on population dynamics, breeding biology, and feeding ecology to successfully manage these species and their ecosystems. Within the Western Region of the USGS, scientists from the Alaska Science Center (ASC), Western Ecological Research Center (WERC), and Pacific Islands Ecosystems Research Center are leading the way in conducting research on many of these little known species. Their aim is to improve our understanding of seabirds in the Pacific and to provide information to support informed management of the birds and their ecosystems.

ARM Aerial Facility ArcticShark Unmanned Aerial System

NASA Astrophysics Data System (ADS)

Schmid, B.; Hubbell, M.; Mei, F.; Carroll, P.; Mendoza, A.; Ireland, C.; Lewko, K.

2017-12-01

The TigerShark Block 3 XP-AR "ArcticShark" Unmanned Aerial System (UAS), developed and manufactured by Navmar Applied Sciences Corporation (NASC), is a single-prop, 60 hp rotary-engine platform with a wingspan of 6.5 m and Maximum Gross Takeoff Weight of 295 Kg. The ArcticShark is owned by the U.S. Department of Energy (DOE) and has been operated by Pacific Northwest National Laboratory (PNNL) since March 2017. The UAS will serve as an airborne atmospheric research observatory for DOE ARM, and, once fully operational, can be requested through ARM's annual call for proposals. The Arctic Shark is anticipated to measure a wide range of radiative, aerosol, and cloud properties using a variable instrument payload weighing up to 46 Kg. SATCOM-equipped, it is capable of taking measurements up to altitudes of 5.5 Km over ranges of up to 500 Km. The ArcticShark operates at airspeeds of 30 to 40 m/s, making it capable of slow sampling. With a full fuel load, its endurance exceeds 8 hours. The aircraft and its Mobile Operations Center (MOC) have been hardened specifically for operations in colder temperatures.ArcticShark's design facilitates rapid integration of various types of payloads. 2500 W of its 4000 W electrical systems is dedicated to payload servicing. It has an interior payload volume of almost 85 L and four wing-mounted pylons capable of carrying external probes. Its payload bay volume, electrical power, payload capacity, and flight characteristics enable the ArcticShark to accommodate multiple combinations of payloads in numerous configurations. Many instruments will be provided by the ARM Aerial Facility (AAF), but other organizations may eventually propose instrumentation for specific campaigns. AAF-provided measurement capabilities will include the following atmospheric state and thermodynamics: temperature, pressure, winds; gases: H2O and CO2; up- and down-welling broadband infrared and visible radiation; surface temperature; aerosol number concentration, size distribution, absorption composition (filter samples), and cloud-droplet size distribution.

Correlated declines in Pacific arctic snow and sea ice cover

USGS Publications Warehouse

Stone, Robert P.; Douglas, David C.; Belchansky, Gennady I.; Drobot, Sheldon

2005-01-01

Simulations of future climate suggest that global warming will reduce Arctic snow and ice cover, resulting in decreased surface albedo (reflectivity). Lowering of the surface albedo leads to further warming by increasing solar absorption at the surface. This phenomenon is referred to as “temperature–albedo feedback.” Anticipation of such a feedback is one reason why scientists look to the Arctic for early indications of global warming. Much of the Arctic has warmed significantly. Northern Hemisphere snow cover has decreased, and sea ice has diminished in area and thickness. As reported in the Arctic Climate Impact Assessment in 2004, the trends are considered to be outside the range of natural variability, implicating global warming as an underlying cause. Changing climatic conditions in the high northern latitudes have influenced biogeochemical cycles on a broad scale. Warming has already affected the sea ice, the tundra, the plants, the animals, and the indigenous populations that depend on them. Changing annual cycles of snow and sea ice also affect sources and sinks of important greenhouse gases (such as carbon dioxide and methane), further complicating feedbacks involving the global budgets of these important constituents. For instance, thawing permafrost increases the extent of tundra wetlands and lakes, releasing greater amounts of methane into the atmosphere. Variable sea ice cover may affect the hemispheric carbon budget by altering the ocean–atmosphere exchange of carbon dioxide. There is growing concern that amplification of global warming in the Arctic will have far-reaching effects on lower latitude climate through these feedback mechanisms. Despite the diverse and convincing observational evidence that the Arctic environment is changing, it remains unclear whether these changes are anthropogenically forced or result from natural variations of the climate system. A better understanding of what controls the seasonal distributions of snow and ice is fundamental to the problem.

Boundary layer and free-tropospheric dimethyl sulfide in the Arctic spring and summer

NASA Astrophysics Data System (ADS)

Ghahremaninezhad, Roghayeh; Norman, Ann-Lise; Croft, Betty; Martin, Randall V.; Pierce, Jeffrey R.; Burkart, Julia; Rempillo, Ofelia; Bozem, Heiko; Kunkel, Daniel; Thomas, Jennie L.; Aliabadi, Amir A.; Wentworth, Gregory R.; Levasseur, Maurice; Staebler, Ralf M.; Sharma, Sangeeta; Leaitch, W. Richard

2017-07-01

Vertical distributions of atmospheric dimethyl sulfide (DMS(g)) were sampled aboard the research aircraft Polar 6 near Lancaster Sound, Nunavut, Canada, in July 2014 and on pan-Arctic flights in April 2015 that started from Longyearbyen, Spitzbergen, and passed through Alert and Eureka, Nunavut, and Inuvik, Northwest Territories. Larger mean DMS(g) mixing ratios were present during April 2015 (campaign mean of 116 ± 8 pptv) compared to July 2014 (campaign mean of 20 ± 6 pptv). During July 2014, the largest mixing ratios were found near the surface over the ice edge and open water. DMS(g) mixing ratios decreased with altitude up to about 3 km. During April 2015, profiles of DMS(g) were more uniform with height and some profiles showed an increase with altitude. DMS reached as high as 100 pptv near 2500 m. Relative to the observation averages, GEOS-Chem (www.geos-chem.org) chemical transport model simulations were higher during July and lower during April. Based on the simulations, more than 90 % of the July DMS(g) below 2 km and more than 90 % of the April DMS(g) originated from Arctic seawater (north of 66° N). During April, 60 % of the DMS(g), between 500 and 3000 m originated from Arctic seawater. During July 2014, FLEXPART (FLEXible PARTicle dispersion model) simulations locate the sampled air mass over Baffin Bay and the Canadian Arctic Archipelago 4 days back from the observations. During April 2015, the locations of the air masses 4 days back from sampling were varied: Baffin Bay/Canadian Archipelago, the Arctic Ocean, Greenland and the Pacific Ocean. Our results highlight the role of open water below the flight as the source of DMS(g) during July 2014 and the influence of long-range transport (LRT) of DMS(g) from further afield in the Arctic above 2500 m during April 2015.

Wayward youth: Trans-Beringian movement and differential southward migration by Juvenile sharp-tailed sandpipers

USGS Publications Warehouse

Handel, C.M.; Gill, R.E.

2010-01-01

The sharp-tailed sandpiper (Calidris acuminata) is a long-distance migrant that travels each year from breeding grounds in the Russian Arctic to nonbreeding areas in Australasia. Most adults migrate rapidly from breeding grounds along a largely inland route through Asia. Here we report on the highly unusual migratory strategy of this species in which some juveniles, but virtually no adults, take a pronounced detour to western Alaska before proceeding on southward migration. We analyzed data from our own studies in this region and published and unpublished observations and specimen records of sharptailed sandpipers from the entire Pacific Basin. Each autumn, sharp-tailed sandpipers began arriving on coastal graminoid meadows and intertidal habitats throughout western Alaska during the last half of August and the last sandpipers departed from southwestern Alaska during October and November. Body mass of birds banded or collected across multiple years and sites in western Alaska (n = 330) increased by an average of 0.57 ?? 0.06 g per day between mid-August and late October. Records suggest a small, regular movement of juveniles (and a very few adults) along the Asiatic coast, but we estimate from surveys that a few tens of thousands of juveniles stage in western Alaska each autumn. The distribution of sight and specimen records from the Pacific Basin during autumn suggests strongly age-segregated migration routes, with the principal migration of juveniles crossing central and western Oceania in a possible nonstop trans-Pacific flight from Alaska. This is only the second well-documented case of differential migration among birds that involves different routes for adults and juveniles, and it raises intriguing questions about how and why this system has evolved. ?? The Arctic Institute of North America.

Latitudinal Trends in Abundant and Rare Bacterioplankton Community Structure and Diversity in Surface Waters of the Pacific Ocean

NASA Astrophysics Data System (ADS)

Jeffrey, W. H.; Moss, J. A.; Snyder, R.; Pakulski, J. D.

2016-02-01

To fully comprehend planktonic diversity and the roles of microorganisms in global biogeochemical cycling, we must recognize the distribution patterns of planktonic taxa and phylotypes and their controlling environmental factors. To advance this understanding, Illumina sequencing targeting the 16S rRNA gene was used to evaluate latitudinal patterns of bacterial taxa as well as diversity in surface waters in the Pacific Ocean. Surface water was collected at 37 stations at 370 km intervals in a 16,200 km transect from 71 N to 68 S in the Pacific Ocean from August to November 2003. These samples were collected on Sterivex filters and kept continuously at -80 C until recent processing which produced over 200k reads per site, half of which were discernible down to the genus level. Bray-Curtis analysis of known genera produced 4 major clusters—sub-Arctic/Arctic, tropical, temperate, and sub-Antarctic/Antarctic. Analysis of only the rare (< 1%) genera produced the same 4 major clusters, although the clusters were most congruent in their geographic distribution when only the abundant taxa were included. Key phyla responsible for these groupings include genera of the Proteobacteria and Cyanobacteria, and as expected, include the pronounced presence of Prochlorococcus in the temperate and equatorial regions. However, many robust trends such as unipolar and bipolar distribution in both the abundant (≥1%) and rare (< 1%) genera within phyla Verrucomicrobia, Actinobacteria, and Barteriodetes, were also apparent. The data sheds light on distribution patterns of the Oleibacter, Thalassobius, Olleya, Salegentibacter, Ulvibacter, Bizionia, Pirellula, and many other additional, understudied genera. Of the 655 identified genera, no significant gradients in gamma diversity were apparent when 12 commonly used species and phylogenetic indices were applied.

Physics Constrained Stochastic-Statistical Models for Extended Range Environmental Prediction

DTIC Science & Technology

2014-09-30

pressure ( SLP ), respectively]. A major finding of this work, illustrated in Figure 1, is that the North Pacific patterns identified in [1] are part of...Figure II 1. Reconstruction of sea ice concentration, SST, and SLP anomalies in the arctic using NLSA reemergence modes during an active phase of...to reemerge. The geostrophic winds associated with the annular SLP pattern in the right-hand column are cold Northerlies (warm Southerlies) in the

UpTempO Buoys for Understanding and Predictions

DTIC Science & Technology

2016-02-28

fall cooling, and interannually as sea ice retreats and the warming season lengthens. The effort was a contribution to the multi-investigator ONR...relationships between sea ice retreat and upper ocean warming. ACCOMPLISHED I. Buoy deployments and data: We worked with the Pacific Gyre (PG...have for the first time investigated the daily variation in ice edge retreat speed from a pan-arctic perspective. We have found that the pace of ice

Forest Management Policy and Community Well-Being in the Pacific Northwest

Treesearch

Susan Charnley; Ellen M. Donoghue; Cassandra Moseley

2008-01-01

This study uses a multiscale, multimethods approach to examine the effects of declining timber harvests on the well-being of forest communities in the Pacific Northwest as a result of the Northwest Forest Plan (the Plan). We found that the effects of declining timber harvests were variable and depended on the importance of the timber sector in a community in the late...

Forest management policy and community well-being in the Pacific Northwest

Treesearch

Susan Charnley; Ellen M. Donoghue; Cassandra Moseley

2008-01-01

This study uses a multiscale, multimethods approach to examine the effects of declining timber harvests on the well-being of forest communities in the Pacific Northwest as a result of the Northwest Forest Plan (the Plan). We found that the effects of declining timber harvests were variable and depended on the importance of the timber sector in a community in the late...

Effect of the tropical Pacific and Indian Ocean warming since the late 1970s on wintertime Northern Hemispheric atmospheric circulation and East Asian climate interdecadal changes

NASA Astrophysics Data System (ADS)

Chu, Cuijiao; Yang, Xiu-Qun; Sun, Xuguang; Yang, Dejian; Jiang, Yiquan; Feng, Tao; Liang, Jin

2018-04-01

Observation reveals that the tropical Pacific-Indian Ocean (TPIO) has experienced a pronounced interdecadal warming since the end of the 1970s. Meanwhile, the wintertime midlatitude Northern Hemispheric atmospheric circulation and East Asian climate have also undergone substantial interdecadal changes. The effect of the TPIO warming on these interdecadal changes are identified by a suite of AMIP-type atmospheric general circulation model experiments in which the model is integrated from September 1948 to December 1999 with prescribed historical, observed realistic sea surface temperature (SST) in a specific region and climatological SST elsewhere. Results show that the TPIO warming reproduces quite well the observed Northern Hemispheric wintertime interdecadal changes, suggesting that these interdecadal changes primarily originate from the TPIO warming. However, each sub-region of TPIO has its own distinct contribution. Comparatively, the tropical central-eastern Pacific (TCEP) and tropical western Pacific (TWP) warming makes dominant contributions to the observed positive-phase PNA-like interdecadal anomaly over the North Pacific sector, while the tropical Indian Ocean (TIO) warming tends to cancel these contributions. Meanwhile, the TIO and TWP warming makes dominant contributions to the observed positive NAO-like interdecadal anomaly over the North Atlantic sector as well as the interdecadal anomalies over the Eurasian sector, although the TWP warming's contribution is relatively small. These remote responses are directly attributed to the TPIO warming-induced tropical convection, rainfall and diabatic heating increases, in which the TIO warming has the most significant effect. Moreover, the TPIO warming excites a Gill-type pattern anomaly over the tropical western Pacific, with a low-level anticyclonic circulation anomaly over the Philippine Sea. Of three sub-regions, the TIO warming dominates such a pattern, although the TWP warming tends to cancel this effect. The anticyclonic circulation anomaly intensifies the southwesterly flow that transfers more moisture from the Bay of Bengal to East Asia and considerably increases the winter precipitation over the southern East Asia. This is strongly supported by the observational fact that there has been a significant interdecadal increase of winter precipitation over the southern China since the end of the 1970s.

NSF-supported education/outreach program takes young researchers to the Arctic

NASA Astrophysics Data System (ADS)

Alexeev, V. A.; Walsh, J. E.; Hock, R.; Repina, I.; Kaden, U.; Bartholomew, L.

2014-12-01

Today, more than ever, an integrated cross-disciplinary approach is necessary to explain changes in the Arctic and understand their implications for the human environment. Advanced training and active involvement of early-career scientists is an important component of this cross-disciplinary approach. This effort led by the International Arctic Research Center at the University of Alaska Fairbanks (UAF) started in 2003. The newly supported project in 2013 is planning four summer schools (one per year) focused on four themes in four different Arctic locations. It provides the participants with an interdisciplinary perspective on Arctic change and its impacts on diverse sectors of the North. It is linked to other ongoing long-term observational and educational programs (e.g. NABOS, Nansen and Amundsen Basins Observational System; LTER, Long Term Environmental Research) and targets young scientists by using the interdisciplinary and place-based setting to broaden their perspective on Arctic change and to enhance their communication skills. Each course for 15-20 people consists of classroom and hands-on components and work with a multidisciplinary group of mentors on projects devoted to themes exemplified by the location. An education/outreach specialist from the Miami Science Museum covers the activities and teaches students the important science communications skills. A specialist from the School of Education at UAF evaluates student's progress during the summer schools. Lessons learned during the 12 years of conducting summer schools, methods of attracting in-kind support and approaches to teaching students are prominently featured in this study. Activities during the two most recent schools, one conducted in the Arctic Ocean jointly with the 2013 NABOS expedition and another on an Alaskan glacier in 2014 is another focus of this work.

Availability, Price, and Affordability of Selected Essential Medicines for Chronic Diseases in 11 Countries of the Asia Pacific Region: A Secondary Analysis.

PubMed

Wang, Haipeng; Sun, Qiang; Vitry, Agnes; Nguyen, Tuan Anh

2017-05-01

Access to affordable essential medicines for noncommunicable, chronic diseases is critical in management of the diseases. This study aims to assess the availability, prices, and affordability of medicines for common chronic diseases in the Asia Pacific Region (APR). A secondary analysis of medicines price and availability data from the Health Action International's (HAI) database was undertaken using the standardized WHO/HAI methodology. The median availability of any medicine in the public sector was 35.5% compared with 56.7% in the private sector. Countries paid 1.4 times the International Reference Price to procure lowest-priced generics (LPGs) and 9.1 times for innovator brands (IBs). Patients would have to spend 2.3 and 0.4 day's wages to purchase one month's treatment of a chronic disease for IBs and LPGs, respectively in the private sector. These findings highlight the need to increase availability, reduce prices, and improve affordability of the medicines.

Polygon on Mars

NASA Technical Reports Server (NTRS)

2008-01-01

This image shows a small-scale polygonal pattern in the ground near NASA's Phoenix Mars Lander. This pattern is similar in appearance to polygonal structures in icy ground in the arctic regions of Earth.

Phoenix touched down on the Red Planet at 4:53 p.m. Pacific Time (7:53 p.m. Eastern Time), May 25, 2008, in an arctic region called Vastitas Borealis, at 68 degrees north latitude, 234 degrees east longitude.

This image was acquired by the Surface Stereo Imager shortly after landing. On the Phoenix mission calendar, landing day is known as Sol 0, the first Martian day of the mission.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Sea Ice in the Chukchi Sea

NASA Image and Video Library

2017-12-08

The U.S. Coast Guard Cutter Healy encountered only small patches of sea ice in the Chukchi Sea during the final days collecting ocean data for the 2011 ICESCAPE mission. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Retrieving the CTD:Rosette

NASA Image and Video Library

2017-12-08

On June 28, 2011, Holley Kelly, a teacher from Farragut High School, helped retrieve the CTD/Rosette ensemble from the Bering Strait, east of the Diomede Islands. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Retrieving Dropped Supplies

NASA Image and Video Library

2017-12-08

On July 12, 2011, crew from the U.S. Coast Guard Cutter Healy retrieved a canister dropped by parachute from a C-130, which brought supplies for some mid-mission fixes. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Healy at 3rd Ice Station

NASA Image and Video Library

2012-06-07

On July 6, 2011, the U.S. Coast Guard Cutter Healy parked in an ice floe for the 2011 ICESCAPE mission's third ice station in the Chukchi Sea. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Mapping an Ice Station

NASA Image and Video Library

2017-12-08

On July 10, 2011, Melinda Webster of University of Washington mapped the locations where measurements were collected during the 2011 ICESCAPE mission's fourth sea ice station in the Chukchi Sea. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Measuring Light

NASA Image and Video Library

2017-12-08

On July 13, 2011, Don Perovich, of Cold Regions Research and Engineering Laboratory, measured the light that drives photosynthesis at the sixth sea ice station of the 2011 ICESCAPE mission. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The growing importance of retirement income in timber-dependent areas.

Treesearch

Debra J. Salazar; Con H. Schallau; Robert G. Lee

1986-01-01

This paper examines five "timber-dependent" counties in the Pacific Northwest to document: (1) net migration rates of older (and presumably retired) people into these counties, and (2) changes in the economic base of each county during the 1970's. We identify a "retirement" sector and argue that it has become a major economic sector in three of...

Global effects of accelerated tariff liberalization in the forest products sector to 2010.

Treesearch

Shushuai Zhu; Joseph Buongiorno; David J. Brooks

2002-01-01

This study projects the effects of tariff elimination on the world sector. Projections were done for two scenarios: (1) progressive tariff elimination according to the schedule agreed to under the current General Agreement on Tariff or Trade (GATT) and (2) complete elimination of tariff on wood products as proposed within the Asia-Pacific Economic Cooperation (APEC)...

INTAROS: Development of an integrated Arctic observation system under Horizon 2020

NASA Astrophysics Data System (ADS)

Beszczynska-Möller, Agnieszka; Sandven, Stein; Sagen, Hanne

2017-04-01

INTAROS is a research and innovation action funded under the H2020-BG-09 call for the five-year period 2016-2021. INTAROS will develop an integrated Arctic Observation System (iAOS) by extending, improving and unifying existing systems in the different regions of the Arctic. INTAROS will have a strong multidisciplinary focus, with tools for integration of data from atmosphere, ocean, cryosphere and terrestrial sciences, provided by institutions in Europe, North America and Asia. Satellite earth observation (EO) data plays an increasingly important role in such observing systems, because the amount of EO data for observing the global climate and environment grows year by year. EO data will therefore be integrated into iAOS based on existing products and databases. In situ observing systems are much more limited due to logistical constraints and cost limitations. The sparseness of in situ data is therefore the largest gap in the overall observing system. INTAROS will assess strengths and weaknesses of existing Arctic observing systems and contribute with innovative solutions to fill some of the critical gaps in the selected networks. INTAROS will develop a platform, iAOS, to search for and access data from distributed databases. The evolution into a sustainable Arctic observing system requires coordination, mobilization and cooperation between the existing European and international infrastructures (in-situ and remote, including space-based), the modeling communities and relevant stakeholder groups. INTAROS will include development of community-based observing systems, where local knowledge is merged with scientific data. Multidisciplinary data integrated under INTAROS will contribute to better understanding of interactions and coupling in the complex Arctic ice-ocean-land-atmosphere system. An integrated Arctic Observation System will enable better-informed decisions and better-documented processes within key sectors (e.g. local communities, shipping, tourism, fishing), in order to strengthen the societal and economic role of the Arctic region and support the EU strategy for the Arctic and related maritime and environmental policies. Following the SAON goal, INTAROS will support and strengthen the EU engagement in developing the sustained and coordinated pan-Arctic observing and data sharing systems.

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

NASA Astrophysics Data System (ADS)

de Steur, L.; Steele, M.; Hansen, E.; Morison, J.; Polyakov, I.; Olsen, S. M.; Melling, H.; McLaughlin, F. A.; Kwok, R.; Smethie, W. M.; Schlosser, P.

2013-09-01

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 1100±250km3, approximately 13% of the total estimated FW increase in the Arctic in 2008.

Science Partnerships for a Sustainable Arctic: the Marine Mammal Nexus (Invited)

NASA Astrophysics Data System (ADS)

Moore, S. E.

2010-12-01

Marine mammals are both icons of Arctic marine ecosystems and fundamental to Native subsistence nutrition and culture. Eight species are endemic to the Pacific Arctic, including the polar bear, walrus, ice seals (4 species), beluga and bowhead whales. Studies of walrus and bowheads have been conducted over the past 30 years, to estimate population size and elucidate patterns of movement and abundance. With regard to the three pillars of the SEARCH program, these long-term OBSERVATIONS provide a foundation for research seeking to UNDERSTAND and RESPOND to the effects of rapid climate change on the marine ecosystem. Specifically, research on the coastal ecosystem near Barrow, Alaska focuses on late-summer feeding habitat for bowheads in an area where whales are hunted in autumn. This work is a partnership among agency, academic and local scientists and the residents of Barrow, all of whom seek to better UNDERSTAND how recent dramatic changes in sea ice, winds and offshore industrial activities influence whale movements and behavior. In regard to RESPONDING to climate change, the nascent Sea Ice for Walrus Outlook (SIWO) is a science partnership that projects sea ice and wind conditions for five villages in the Bering Strait region. The objective of the SIWO is to provide information on physical conditions in the marine environment at spatial and temporal scales relevant to walrus hunters. Marine mammals are a strong and dynamic nexus for partnerships among scientists, Arctic residents, resource managers and the general public - as such, they are essential elements to any science plan for a sustainable Arctic.

Distribution, abundance, and predation effects of epipelagic ctenophores and jellyfish in the western Arctic Ocean

NASA Astrophysics Data System (ADS)

Purcell, Jennifer E.; Hopcroft, Russell R.; Kosobokova, Ksenia N.; Whitledge, Terry E.

2010-01-01

The Arctic Ocean is undergoing changes at an unprecedented rate because of global climate change. Especially poorly-studied in arctic waters are the gelatinous zooplankton, which are difficult to study using traditional oceanographic methods. A distinct zooplanktivore community was characterized in the surface 100 m by use of a Remotely Operated Vehicle, net collections, and SCUBA diving. The large scyphomedusa, Chrysaora melanaster, was associated with the warm Pacific water at ˜35-75 m depth. A diverse ctenophore community lived mainly above the C. melanaster layer, including Dryodora glandula, a specialized predator of larvaceans, Beroe cucumis, a predator of other ctenophores, and the extremely fragile Bolinopsis infundibulum, which was the most abundant species. Gut content analyses showed that Mertensia ovum selectively consumed the largest copepods ( Calanus spp.) and amphipods ( Parathemisto libellula); B. infundibulum consumed smaller copepods and pteropods ( Limacina helicina). Large copepods were digested by M. ovum in ˜12 h at -1.5 to 0 °C, but by B. infundibulum in only ˜4 h. We estimated that M. ovum consumed an average of ˜2% d -1 of the Calanus spp. copepods and that B. infundibulum consumed ˜4% d -1 of copepods <3 mm prosome length. These are significant consumption rates given that Calanus spp. have life-cycles of 2 or more years and are eaten by vertebrates including bowhead whales and arctic cod.

Hydrology of the North Klondike River: carbon export, water balance and inter-annual climate influences within a sub-alpine permafrost catchment.

PubMed

Lapp, Anthony; Clark, Ian; Macumber, Andrew; Patterson, Tim

2017-10-01

Arctic and sub-arctic watersheds are undergoing significant changes due to recent climate warming and degrading permafrost, engendering enhanced monitoring of arctic rivers. Smaller catchments provide understanding of discharge, solute flux and groundwater recharge at the process level that contributes to an understanding of how larger arctic watersheds are responding to climate change. The North Klondike River, located in west central Yukon, is a sub-alpine permafrost catchment, which maintains an active hydrological monitoring station with a record of >40 years. In addition to being able to monitor intra-annual variability, this data set allows for more complex analysis of streamflow records. Streamflow data, geochemistry and stable isotope data for 2014 show a groundwater-dominated system, predominantly recharged during periods of snowmelt. Radiocarbon is shown to be a valuable tracer of soil zone recharge processes and carbon sources. Winter groundwater baseflow contributes 20 % of total annual discharge, and accounts for up to 50 % of total river discharge during the spring and summer months. Although total stream discharge remains unchanged, mean annual groundwater baseflow has increased over the 40-year monitoring period. Wavelet analysis reveals a catchment that responds to El Niño and longer solar cycles, as well as climatic shifts such as the Pacific Decadal Oscillation. Dedicated to Professor Peter Fritz on the occasion of his 80th birthday.

Large eddy simulation of heat entrainment under Arctic sea ice

NASA Astrophysics Data System (ADS)

Ramudu, Eshwan; Gelderloos, Renske; Yang, Di; Meneveau, Charles; Gnanadesikan, Anand

2017-11-01

Sea ice cover in the Arctic has declined rapidly in recent decades. To better understand ice loss through bottom melting, we choose to study the Canada Basin of the Arctic Ocean, which is characterized by a perennial anomalously warm Pacific Summer Water (PSW) layer residing at the base of the mixed layer and a summertime Near-Surface Temperature Maximum (NSTM) layer trapping heat from solar radiation. The interaction of these warm layers with a moving ice basal surface is investigated using large eddy simulation. We find that the presence of the NSTM enhances heat entrainment from the mixed layer. Another conclusion from our work is that there is no heat entrained from the PSW layer, even at the largest ice-drift velocity of 0.3 m s-1 considered. We propose a scaling law for the heat flux at the ice basal surface which depends on the initial temperature anomaly in the NSTM layer and the ice-drift velocity. A case study of `The Great Arctic Cyclone of 2012' gives a turbulent heat flux from the mixed layer that is approximately 70% of the total ocean-to-ice heat flux estimated from the PIOMAS model often used for short-term predictions. Present results highlight the need for large-scale climate models to account for the NSTM layer. We acknowledge funding from NOAA Grant NA15OAR4310172, the NSF, and the University of Houston start-up fund.

Seawater-derived neodymium isotope records in the Chukchi Sea, western Arctic Ocean during Holocene: implications for oceanographic circulation

NASA Astrophysics Data System (ADS)

Lee, Borom; Nam, Seung-Il; Huh, Youngsook; Lee, Mi Jung

2015-04-01

Changes in oceanographic circulation in the Artic have a large influence on the global oceanic and climate system of the Earth through the geological times. In particular, freshwater input from the North Pacific to the western Arctic Ocean affects the Atlantic meridional overturning circulation (AMOC) after the opening of the Bering Strait. Seawater-derived neodymium isotope in marine sediments has been used as a proxy to trace the origin of water masses and oceanic circulation system. The global average residence time of Nd is shorter than the global ocean mixing time and dissolved Nd in seawater behaves quasi-conservatively. In the modern Arctic Ocean, the Nd isotope distribution is dominated by Atlantic source water, although the circum-Arctic riverine discharge and Pacific-derived waters also have noticeable impacts. In this study, we investigated seawater-derived neodymium isotope records from a sediment core recovered from the Chukchi Sea to understand the changes in hydrograhic circulation of the western Arctic during the Holocene. A gravity core, ARA02B 01A, was collected on the northern shelf of the Chukchi Sea (73°37.8939'N, 166°30.9838'W, ca. 111 m in water depth) during the RV Araon expedition in 2011. To obtain seawater-derived Nd records, we extracted Fe-Mn oxide coatings as an authigenic fraction from bulk sediments by leaching with acid-reducing solution after removing carbonate by leaching with acetic acid. Our preliminary results might show a general pattern of increasing radiogenic ɛNd values through Holocene intervals. Therefore, it implies that ɛNd results may be related with variations in the intensity of Bering Strait inflow during the last ~9.31 ka BP. The radiogenic trend was strongly pronounced from the late Holocene (ɛNd -7.23; ca. 8.84 ka BP) to the middle Holocene (ɛNd -4.78; ca. 6.18 ka BP) and vaguely during the middle Holocene. After 4.13 ka BP, ɛNd values were increased again from -4.86 to -4.03 at 0.57 ka BP. But 87Sr/86Sr values vary from 0.70929 to 0.70991 throughout the whole sediment core and they might be higher than the Sr isotopic value of modern seawater (0.70918). This implies that the leachates may not be preserved past seawater signal. Thus, our preliminary results indicate that further studies for assessment of leaching methods and for other reliable seawater-derived records (including authigenic carbonates, i.e., foraminiferal and bivalve shells which are found in sediment cores) are necessary.

Collaboration for Actionable Climate Science in Hawaii and the US-Affiliated Pacific Islands

NASA Astrophysics Data System (ADS)

Keener, V. W.; Grecni, Z. N.; Helweg, D. A.

2016-12-01

Hawaii and the US-Affiliated Pacific Islands (USAPI) encompass more than 2000 islands spread across millions of square miles of ocean. Islands can be high volcanic or low atolls, and vary widely in terms of geography, climate, ecology, language, culture, economies, government, and vulnerability to climate change impacts. For these reasons, meaningful collaboration across research groups and climate organizations is not only helpful, it is mandatory. No single group can address all the needs of every island, stakeholder, or sector, which has led to close collaboration and leveraging of research in the region to fill different niches. The NOAA-funded Pacific Regional Integrated Sciences & Assessments (RISA) program, DOI Pacific Islands Climate Science Center (PICSC), and the DOI LCC the Pacific Islands Climate Change Cooperative (PICCC) all take a stakeholder oriented approach to climate research, and have successfully collaborated on both specific projects and larger initiatives. Examples of these collaborations include comprising the core team of the Pacific Islands Regional Climate Assessment (PIRCA), the regional arm of the US National Climate Assessment, co-sponsoring a workshop on regional downscaling for scientists and managers, leveraging research projects across multiple sectors on a single island, collaborating on communication products such as handouts and websites to ensure a consistent message, and in the case of the Pacific RISA and the PICSC, jointly funding a PIRCA Sustained Assessment Specialist position. Barriers to collaboration have been around topics such as roles of research versus granting groups, perceived research overlap, and funding uncertainties. However, collaborations have been overwhelming positive in the Pacific Islands region due to communication, recognition of partners' strengths and expertise, and especially because of the "umbrella" organization and purpose provided by the PIRCA structure, which provides a shared platform for all regional groups working on climate science and adaptation, not owned by any one group. This work will give examples of successes and barriers encountered in the region.

Pre-industrial and recent (1970-2010) atmospheric deposition of sulfate and mercury in snow on southern Baffin Island, Arctic Canada.

PubMed

Zdanowicz, Christian; Kruemmel, Eva; Lean, David; Poulain, Alexandre; Kinnard, Christophe; Yumvihoze, Emmanuel; Chen, JiuBin; Hintelmann, Holger

2015-03-15

Sulfate (SO4(2-)) and mercury (Hg) are airborne pollutants transported to the Arctic where they can affect properties of the atmosphere and the health of marine or terrestrial ecosystems. Detecting trends in Arctic Hg pollution is challenging because of the short period of direct observations, particularly of actual deposition. Here, we present an updated proxy record of atmospheric SO4(2-) and a new 40-year record of total Hg (THg) and monomethyl Hg (MeHg) deposition developed from a firn core (P2010) drilled from Penny Ice Cap, Baffin Island, Canada. The updated P2010 record shows stable mean SO4(2-) levels over the past 40 years, which is inconsistent with observations of declining atmospheric SO4(2-) or snow acidity in the Arctic during the same period. A sharp THg enhancement in the P2010 core ca 1991 is tentatively attributed to the fallout from the eruption of the Icelandic volcano Hekla. Although MeHg accumulation on Penny Ice Cap had remained constant since 1970, THg accumulation increased after the 1980s. This increase is not easily explained by changes in snow accumulation, marine aerosol inputs or air mass trajectories; however, a causal link may exist with the declining sea-ice cover conditions in the Baffin Bay sector. The ratio of THg accumulation between pre-industrial times (reconstructed from archived ice cores) and the modern industrial era is estimated at between 4- and 16-fold, which is consistent with estimates from Arctic lake sediment cores. The new P2010 THg record is the first of its kind developed from the Baffin Island region of the eastern Canadian Arctic and one of very few such records presently available in the Arctic. As such, it may help to bridge the knowledge gap linking direct observation of gaseous Hg in the Arctic atmosphere and actual net deposition and accumulation in various terrestrial media. Copyright © 2014 Elsevier B.V. All rights reserved.

Perceptions of earthquake and tsunami issues in U.S. Pacific Northwest port and harbor communities

USGS Publications Warehouse

Wood, Nathan J.; Good, James W.

2005-01-01

Although there is considerable energy focused on assessing natural hazards associated with earthquakes and tsunamis in the U.S. Pacific Northwest, little has been done to understand societal vulnerability to these hazards. Part of understanding societal vulnerability includes assessing the perceptions and priorities of public sector individuals with traditional emergency management responsibilities and of private citizens who could play key roles in community recovery. In response to this knowledge gap, we examine earthquake and tsunami perceptions of stakeholders and decision makers from coastal communities in the U.S. Pacific Northwest, focusing on perceptions of (1) regional hazards and societal vulnerability, (2) the current state of readiness, and (3) priorities for future hazard adjustment efforts. Results of a mailed survey suggest that survey participants believe that earthquakes and tsunamis are credible community threats. Most communities are focusing on regional mitigation and response planning, with less effort devoted to recovery plans or to making individual organizations more resilient. Significant differences in expressed perceptions and priorities were observed between Oregon and Washington respondents, mainly on tsunami issues. Significant perception differences were also observed between private and public sector respondents. Our results suggest the need for further research and for outreach and planning initiatives in the Pacific Northwest to address significant gaps in earthquake and tsunami hazard awareness and readiness.

Global Diversity of Marine Isopods (Except Asellota and Crustacean Symbionts)

PubMed Central

Poore, Gary C. B.; Bruce, Niel L.

2012-01-01

The crustacean order Isopoda (excluding Asellota, crustacean symbionts and freshwater taxa) comprise 3154 described marine species in 379 genera in 37 families according to the WoRMS catalogue. The history of taxonomic discovery over the last two centuries is reviewed. Although a well defined order with the Peracarida, their relationship to other orders is not yet resolved but systematics of the major subordinal taxa is relatively well understood. Isopods range in size from less than 1 mm to Bathynomus giganteus at 365 mm long. They inhabit all marine habitats down to 7280 m depth but with few doubtful exceptions species have restricted biogeographic and bathymetric ranges. Four feeding categories are recognised as much on the basis of anecdotal evidence as hard data: detritus feeders and browsers, carnivores, parasites, and filter feeders. Notable among these are the Cymothooidea that range from predators and scavengers to external blood-sucking micropredators and parasites. Isopods brood 10–1600 eggs depending on individual species. Strong sexual dimorphism is characteristic of several families, notably in Gnathiidae where sessile males live with a harem of females while juvenile praniza stages are ectoparasites of fish. Protandry is known in Cymothoidae and protogyny in Anthuroidea. Some Paranthuridae are neotenous. About half of all coastal, shelf and upper bathyal species have been recorded in the MEOW temperate realms, 40% in tropical regions and the remainder in polar seas. The greatest concentration of temperate species is in Australasia; more have been recorded from temperate North Pacific than the North Atlantic. Of tropical regions, the Central Indo-Pacific is home to more species any other region. Isopods are decidedly asymmetrical latitudinally with 1.35 times as many species in temperate Southern Hemisphere than the temperate North Atlantic and northern Pacific, and almost four times as many Antarctic as Arctic species. More species are known from the bathyal and abyssal Antarctic than Arctic GOODS provinces, and more from the larger Pacific than Atlantic oceans. Two areas with many species known are the New Zealand-Kermadec and the Northern North Pacific provinces. Deep hard substrates such as found on seamounts and the slopes are underrepresented in samples. This, the documented numbers of undescribed species in recent collections and probable cryptic species suggest a large as yet undocumented fauna, potentially an order of magnitude greater than presently known. PMID:22952700

Coastal Environment, Bathymetry and Physical Oceanography along the Beaufort, Chukchi and Bering Seas.

DTIC Science & Technology

1980-01-01

Unit No. 347 , Vol. III, Chukchi-Beaufort Sea, 409 pp. 3. Hopkins, D.M. and R.W. Hartz, 1978, Coastal morphology, coastal erosion, and barrier islands of...U.S. Department of Commerce, Alaska Outer Continental Shelf Environmental Assessment Program Final Report, Research Unit No. 347 , vol. III, Chukchi...Assessment Program Final Report, Research Univ No. 347 , vol. II, Bering Sea, 443 pp. 3. U.S. Department of Commerce, 1964, Pacific and Arctic Coasts

Amplified North Atlantic Warming in the Late Pliocene by Changes in Arctic Gateways

NASA Astrophysics Data System (ADS)

Otto-Bliesner, B. L.; Jahn, A.; Feng, R.; Brady, E. C.; Hu, A.; Lofverstrom, M.

2017-12-01

Reconstructions of the late Pliocene (mid-Piacenzian, 3.3 - 3.0 million years ago) sea surface temperature (SST) find much warmer conditions in the North Atlantic than modern. The much warmer SSTs, up to 8.8°C from sites with good dating and replicates from several different types of proxies, have been difficult for climate models to reproduce. Even with the slow feedbacks of a reduced Greenland ice sheet and expansion of boreal forests to the Arctic Ocean over Canada and Eurasia, models cannot warm the North Atlantic sufficiently to match the reconstructed SSTs. An enhancement of the Atlantic Meridional Overturning Circulation (AMOC) during the late Pliocene, proposed as a possible mechanism based on ocean core records of δ13C, also is not present in the model simulations. Here, we present CESM simulations using a new reconstruction of late Pliocene paleogeography that has the Bering Strait (BS) and Canadian Arctic Archipelago (CAA) Straits closed. We find that the closure of these small Arctic gateways strengthens the AMOC, by inhibiting freshwater (FW) transport from the Pacific to the Arctic Ocean and from the Arctic Ocean to the Labrador Sea, leading to warmer sea surface temperatures in the North Atlantic. The cutoff of the short export route through the CAA results in a more saline Labrador and south Greenland Sea with increased deep convection. At the same time, as all FW now leaves the Arctic east of Greenland, there is a freshening of and decreased deepwater formation in the Norwegian Sea. Overall, the AMOC strengthens. This past time period has implications for a future Earth under more responsible scenarios of emissions. Late Pliocene atmospheric carbon dioxide concentrations are estimated to have ranged between 350 and 450 ppmv and the paleogeography is relatively similar to modern. Our study indicates that the state of the Arctic gateways may influence the sensitivity of the North Atlantic climate in complex ways, and better understanding of the state of these Arctic gateways for past time periods is needed. The late Pliocene may be a better process than geologic analogue to study the ability of models to realize the full sensitivity to processes and feedbacks that may affect the Earth system sensitivity in the future.

Multiyear Measurements of Flame Retardants and Organochlorine Pesticides in Air in Canada's Western Sub-Arctic.

PubMed

Yu, Yong; Hung, Hayley; Alexandrou, Nick; Roach, Pat; Nordin, Ken

2015-07-21

Fourteen polybrominated diphenyl ethers (PBDEs), 14 non-BDE flame retardants (FRs), and 25 organochlorine pesticides (OCPs) were analyzed in air samples collected at Little Fox Lake (LFL) in Canada's Yukon Territory from August 2011 to December 2014. LFL is a long-term monitoring station operated under the Northern Contaminants Program (NCP) and one of only a few stations that contribute to the assessment of air pollution levels and pathways to the sub-Arctic region. BDE-47 was the most abundant congener among the 14 PBDEs, followed by BDE-99. Non-BDE FRs pentabromotoluene (PBT) and dechlorane plus (DP) were detected in all the samples. Dechlorane 602, 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE), hexabromobenzene (HBB), and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) were also detected in >75% of all samples. PBDEs have shown a decreasing tendency as of 2013, which may reflect the phase-out of penta- and octa-BDE mixtures has led to significant decline in the atmosphere. The highest concentrations of OCPs were observed for hexachlorobenzene (HCB), with a median concentration of 61 pg/m(3), followed by α-hexachlorocyclohexane (α-HCH) and α-endosulfan. Potential source contribution function (PSCF) highlights Northern Canada, Pacific, and East Asia as potential sources in warm seasons; whereas in cold seasons, the chemicals mainly came from the Pacific Rim.

North Pacific decadal climate variability since 1661

USGS Publications Warehouse

Biondi, Franco; Gershunov, Alexander; Cayan, Daniel R.

2001-01-01

Climate in the North Pacific and North American sectors has experienced interdecadal shifts during the twentieth century. A network of recently developed tree-ring chronologies for Southern and Baja California extends the instrumental record and reveals decadal-scale variability back to 1661. The Pacific decadal oscillation (PDO) is closely matched by the dominant mode of tree-ring variability that provides a preliminary view of multiannual climate fluctuations spanning the past four centuries. The reconstructed PDO index features a prominent bidecadal oscillation, whose amplitude weakened in the late l700s to mid-1800s. A comparison with proxy records of ENSO suggests that the greatest decadal-scale oscillations in Pacific climate between 1706 and 1977 occurred around 1750, 1905, and 1947.

The Eurasia-North Pacific Oscillation in atmospheric mass variations independent of both IHO and AO and its possible impacts on winter climate

NASA Astrophysics Data System (ADS)

Zhang, Qian; Guan, Zhaoyong; Li, Minggang

2018-06-01

Using NCEP/NCAR reanalysis, we have investigated the features of migrations of atmospheric mass (AM) between land and ocean in Eurasia-North Pacific domain in boreal winter after having both signals of Inter-hemispheric Oscillation and Arctic Oscillation removed from the physical quantities. It is found that there is a Eurasia-North Pacific Oscillation (ENPO) in surface air pressure anomalies. This ENPO pattern characterizes with two oppositely signed anomalous surface pressure centers over Eurasia and North Pacific respectively, indicating strong connections between Siberian high and Aleutian low during period 1979-2012. The maintenance of this ENPO teleconnection is significantly associated with three factors including the anomalous AM flows and zonal circulation cell over Eurasia-North Pacific domain, the Rossby wave energy propagations, and the thermal forcing contrasts near the surface between Eurasia and North Pacific during boreal winter. The variations of both wintertime rainfall and temperature over Eurasia may be strongly affected by ENPO. When the ENPO index is positive (negative), there occurs the AM accumulation (depletion) over Eurasia with simultaneous depletion (accumulation) over mid-latitude North-Pacific. Correspondingly, this anomalous surface pressure pattern along with the related circulation anomalies at different isobaric levels possibly results in winter precipitation decreases (increases) over Siberian Plain and East China, whereas increases (decreases) over southeastern Europe, Xinjiang of China, and the west coast of Sea of Okhotsk. On the other hand, surface air temperature decreases (increases) over large areas of Eurasia. These results are helpful for our better understanding the mechanisms behind circulation and winter climate variations over Eurasia-North Pacific region.

Diversity of Indo-West Pacific Siphonaria (Mollusca: Gastropoda: Euthyneura).

PubMed

Dayrat, Benoît; Goulding, Tricia C; White, Tracy R

2014-03-14

Species of the limpet genus Siphonaria (Gastropoda: Euthyneura) are commonly found in the rocky intertidal, worldwide, except in the Arctic. In total, 205 species-group names are available and not permanently invalid. However, estimating the actual species diversity of Siphonaria has remained challenging, mainly because past authors have interpreted differently the variation of shell characters, resulting in different taxonomic accounts. Species diversity of Siphonaria is evaluated for the first time here based on DNA sequence data (three mitochondrial gene fragments: COI, 12S, and 16S) and a large sampling focusing on the tropical and subtropical Indo-West Pacific (from eastern Africa to Hawaii): new sequences are provided for 153 individuals, 123 of which were collected from 93 locations throughout the Indo-West Pacific. In total, 41 species (molecular units) are recognized worldwide (31 from the Indo-West Pacific), all of which are strongly supported. Potential names are discussed for those 41 species, based on traditional taxonomy. The shells of 66 of the individuals from which DNA was extracted are illustrated: intra- and inter-specific variation is documented in detail and discussed in the light of new molecular results. It is shown that many species could hardly be identified based on the shell only, because the variation of shell characters is too high and overlaps between species. Geographically, no species is found across the entire Indo-West Pacific, where quite a few species seem to be endemic to restricted areas. The biogeography of Siphonaria in the Indo-West Pacific is compared to other groups.

Dorset and Thule divergence from East Central Asian roots.

PubMed

Shields, E D; Jones, G

1998-06-01

The history of the immigration of East Asians to America during the last glacial period remains controversial. In an attempt to add critical data to this problem, a large sample of whole teeth derived from Southeast Asian, Mongolian, Thule, Western Inuit, and pre-Inca (Huari) people was quantified (N = 4,507 teeth from 495 individuals; approximately 30 variables per tooth). Multivariate analysis helped establish that all Native Americans were likely derived from one ancient, extinct population that resided in the region of Mongolia (east Central Asia), and that Mongolians and Southeast Asians are two independent groups. A controversial and enigmatic Central Canadian Arctic "Thule culture Inuit" group on Southampton Island that survived until 1902 was identified as a relic, mainly Paleoeskimo Dorset community. Surprisingly, there was little, or no, indication of Dorset-to-Thule gene flow. Cumulatively, the data suggest that a small population of Paleoindian founders remained resident in Beringia, may have blocked further immigration, and were the antecedents to the Thule/Inuit. With the confluence of the Arctic and Pacific oceans at the breakup of Beringia, the resulting increased availability of marine animal food sources allowed this population to increase in size and expand throughout the eastern Arctic.

Transit navigation through Northern Sea Route from satellite data and CMIP5 simulations

NASA Astrophysics Data System (ADS)

Khon, Vyacheslav C.; Mokhov, Igor I.; Semenov, Vladimir A.

2017-02-01

Rapid Arctic sea ice decline over the last few decades opens new perspectives for Arctic marine navigation. Further warming in the Arctic will promote the Northern Sea Route (NSR) as an alternative to the conventional Suez or Panama Canal routes for intercontinental shipping. Here we use both satellite data and CMIP5 ensemble of climate models to estimate the NSR transit window allowing intercontinental navigation between Atlantic and Pacific regions. To this end, we introduce a novel approach to calculate start and end dates of the navigation season along the NSR. We show that modern climate models are able to reproduce the mean time of the NSR transit window and its trend over the last few decades. The selected models demonstrate that the rate of increase of the NSR navigation season will slow down over the next few decades with the RCP4.5 scenario. By the end of the 21st century ensemble-mean estimates show an increase of the NSR transit window by about 4 and 6.5 months according to RCP4.5 and 8.5, respectively. Estimated trends for the end date of the navigation season are found to be stronger compared to those for the start date.

Diversity of Arctic pelagic Bacteria with an emphasis on photoheterotrophs: a review

NASA Astrophysics Data System (ADS)

Boeuf, D.; Humily, F.; Jeanthon, C.

2014-06-01

The Arctic Ocean is a unique marine environment with respect to seasonality of light, temperature, perennial ice cover, and strong stratification. Other important distinctive features are the influence of extensive continental shelves and its interactions with Atlantic and Pacific water masses and freshwater from sea ice melt and rivers. These characteristics have major influence on the biological and biogeochemical processes occurring in this complex natural system. Heterotrophic bacteria are crucial components of marine food webs and have key roles in controlling carbon fluxes in the oceans. Although it was previously thought that these organisms relied on the organic carbon in seawater for all of their energy needs, several recent discoveries now suggest that pelagic bacteria can depart from a strictly heterotrophic lifestyle by obtaining energy through unconventional mechanisms that are linked to the penetration of sunlight into surface waters. These photoheterotrophic mechanisms may play a significant role in the energy budget in the euphotic zone of marine environments. Modifications of light and carbon availability triggered by climate change may favor the photoheterotrophic lifestyle. Here we review advances in our knowledge of the diversity of marine photoheterotrophic bacteria and discuss their significance in the Arctic Ocean gained in the framework of the Malina cruise.

A tale of two basins: An integrated physical and biological perspective of the deep Arctic Ocean

NASA Astrophysics Data System (ADS)

Bluhm, B. A.; Kosobokova, K. N.; Carmack, E. C.

2015-12-01

This review paper integrates the current knowledge, based on available literature, on the physical and biological conditions of the Amerasian and Eurasian basins (AB, EB) of the deep Arctic Ocean (AO) in a comparative fashion. The present day (Holocene) AO is a mediterranean sea that is roughly half continental shelf and half basin and ridge complex. Even more recently it is roughly two thirds seasonally and one third perennially ice-covered, thus now exposing a portion of basin waters to sunlight and wind. Basin boundaries and submarine ridges steer circulation pathways in overlying waters and limit free exchange in deeper waters. The AO is made integral to the global ocean by the Northern Hemisphere Thermohaline Circulation (NHTC) which drives Pacific-origin water (PW) through Bering Strait into the Canada Basin, and counter-flowing Atlantic-origin water (AW) through Fram Strait and across the Barents Sea into the Nansen Basin. As a framework for biogeography within the AO, four basic, large-scale circulation systems (with L > 1000 km) are noted; these are: (1) the large scale wind-driven circulation which forces the cyclonic Trans-Polar Drift from Siberia to the Fram Strait and the anticyclonic Beaufort Gyre in the southern Canada Basin; (2) the circulation of waters that comprise the halocline complex, composed largely of waters of Pacific and Atlantic origin that are modified during passage over the Bering/Chukchi and Barents/Siberian shelves, respectively; (3) the topographically-trapped Arctic Circumpolar Boundary Current (ACBC) which carries AW cyclonically around the boundaries of the entire suite of basins, and (4) the very slow exchange of Arctic Ocean Deep Waters. Within the basin domain two basic water mass assemblies are observed, the difference between them being the absence or presence of PW sandwiched between Arctic Surface Waters (ASW) above and the AW complex below; the boundary between these domains is the Atlantic/Pacific halocline front. Both domains have vertical stratification that constrains the transfer of nutrients to the surface layer (euphotic zone), thus leading to their oligotrophic state, particularly in the more strongly stratified Pacific Arctic where, despite high nutrient values in the inflow, convective reset of surface layer nutrients by haline convection in winter is virtually absent. First and multi-year sea ice drastically alters albedo and insulates the underlying water column from extreme winter heat loss while its mechanical properties (thickness, concentration, roughness, etc.) greatly affect the efficiency of momentum transfer from the wind to the underlying water. Biologically, sea ice algal growth in the basins is proportionally almost equal to or exceeding phytoplankton production, and is a habitat and transport platform for sympagic (ice-associated) fauna. Owing to nutrient limitation due to strong stratification and light limitation due to snow and ice cover and extreme sun angle, primary production in the two basin domains is very low compared to the adjacent shelves. Severe nutrient limitation and complete euphotic zone drawdown in the AB favors small phytoplankton, a ubiquitous deep chlorophyll maximum layer, a low f-ratio of new to recycled carbon fixation, and a low energy food web. In contrast, nutrients persist -albeit in low levels- in the western EB, even in summer, suggesting light limitation, heavy grazing or both. The higher stocks of nutrients in the EB are more conducive to marginal ice blooms than in the AB. The large-scale ocean currents (NHTC and ACBC) import substantial expatriate, not locally reproducing zooplankton biomass especially from the adjoining subarctic Atlantic (primarily Calanus finmarchicus), but also from the Pacific (e.g., Pseudocalanus spp., Neocalanus spp. and Metridia pacifica). These advective inputs serve both as source of food to resident pelagic and benthic biota within the basins, and as potential grazers exerting top down control on limited phytoplankton resources. Benthic organisms within the AO basin show previously unappreciated biodiversity and surprising dispersion of species given the isolation of individual basins and low vertical carbon flux and resulting biomass. Larval dispersion is aided by the large-scale flows and perhaps, we hypothesize in the deep benthos by convective updrafts driven by geothermal heating. Zooplankton diversity, in contrast, is low, but again faunal assemblages are equally distributed between the EB and AB. Species pools of both pelagic and benthic communities change more with water depth rather than laterally, with the exception of expatriates and rare species, with close ties to today's North Atlantic biogeographic region. Climate related change in the AO is thus manifest at significantly differing time scales. Throughout ∼90% of the Pleistocene the AO has existed in glacial mode, with narrow continental shelves, greatly restricted river inflow, thicker and perhaps immobile sea ice, and total blockage of exchange with the Pacific Ocean. During the Holocene, on shorter time scales of 1000-100 years, significant changes in high latitude climate are tied to changes in temperature and perhaps moisture delivery patterns. The Arctic also experiences significant multi-decadal variability; however, the pace of change over the past three decades has been without precedent. Within the basin interior the ice is now thinner and less compact, and thus more responsive to wind stress (forcing and mixing). Concurrent with sea ice melt and increased river flow, the accumulation of fresh water and the stratification have increased, thus constraining vertical nutrient flux affecting phytoplankton size distributions, limiting primary production in parts of the basins now and likely in the future, and increasing vulnerability to acidification. In addition, sea ice is now retreating on an annual basis past the shelf break, exposing basin waters directly to sunlight and wind forcing. Thus, upwelling favorable winds (generally from east to west) can now directly and efficiently drive shelf-break upwelling, and draw nutrients from subsurface basin waters onto the shelf; at the same time upwelling favorable winds will also create onshore pressure gradients over the slope and basin which will act to slow or block the flow of waters in the ACBC, and thus alter advective pathways of both abiotic and biotic materials. Given the opening of a new ocean to multiple user groups, we expect that the central AO will play an increasing larger role both in the research and political arenas in the future, and we encourage pan-Arctic international collaboration over focus on territorial boundaries.

Sampling Melt Ponds

NASA Image and Video Library

2017-12-08

On July 10, 2011, Jens Ehn of Scripps Institution of Oceanography (left), and Christie Wood of Clark University (right), scooped water from melt ponds on sea ice in the Chukchi Sea. The water was later analyzed from the Healy's onboard science lab. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Gray whale sightings in the Canadian Beaufort Sea, September 2014

NASA Astrophysics Data System (ADS)

Iwahara, Yuka; Fujiwara, Amane; Ito, Keizo; Miyashita, Kazushi; Mitani, Yoko

2016-06-01

Gray whales (Eschrichtius robustus) are distributed within the productive neritic and estuarine waters of the North Pacific Ocean, the Bering Sea, and adjacent waters of the Arctic Ocean. They migrate to high-latitude feeding grounds each spring. Their main feeding grounds in the Arctic include the Chirikov Basin, the northeastern Chukchi Sea from Pt. Hope to Cape Lisburne and Pt. Lay to Pt. Barrow, and the northwestern Chukchi Sea along the Chukotka coast. Although sightings are rare in the Canadian Beaufort Sea, we observed three gray whales in two groups in this area in September 2014. A mud plume was observed near one of the whales, suggesting the animal had been feeding. In the Alaskan Beaufort Sea, large-scale monitoring of the distributions of marine mammals has been continuously conducted since 1979; however, there has been less monitoring in the Canadian Beaufort Sea. Therefore, it is necessary to record opportunistic sightings, such as those described here.

Maneuvering Melt Ponds

NASA Image and Video Library

2017-12-08

On July 10, 2011, Don Perovich, of Cold Regions Research and Engineering Laboratory, maneuvered through melt ponds collecting optical data along the way to get a sense of the amount of sunlight reflected from sea ice and melt ponds in the Chukchi Sea. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Melt Pond Optics

NASA Image and Video Library

2012-06-07

On July 6, 2011, Don Perovich, of Cold Regions Research and Engineering Laboratory, used a spectroradiometer to measure the amount of sunlight reflected from the surface of ice and melt ponds in the Chukchi Sea. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Cutting Through Multiyear Ice

NASA Image and Video Library

2012-06-07

ICESCAPE scientists watched from the deck of the Healy as it cut a path through thick multiyear ice on July 6, 2011. Cutting the path is key for getting researchers to remote research sites amid the sea ice. Credit: NASA/Kathryn Hansen The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Middle pleistocene mollusks from St. Lawrence Island and their significance for the paleo-oceanography of the Bering Sea

USGS Publications Warehouse

Hopkins, D.M.; Rowland, R.W.; Patton, W.W.

1972-01-01

Drift, evidently of Illinoian age, was deposited on St. Lawrence Island at the margin of an ice cap that covered the highlands of the Chukotka Peninsula of Siberia and spread far eastward on the continental shelf of northern Bering Sea. Underlying the drift on the northwestward part of the island are mollusk-bearing beds deposited during the Kotzebuan Transgression. A comparison of mollusk faunas from St. Lawrence Island, Chukotka Peninsula, and Kotzebue Sound suggests that the present northward flow through Bering and Anadyr Straits was reversed during the Kotzebuan Transgression. Cold arctic water penetrated southward and southwestward bringing an arctic fauna to the Gulf of Anadyr. Warmer Pacific water probably entered eastern Bering Sea, passed eastward and northeastward around eastern and northern St. Lawrence Island, and then became entrained in the southward currents that passed through Anadyr Strait. ?? 1972.

Spatial genetic structure of Long-tailed Ducks (Clangula hyemalis) among Alaskan, Canadian, and Russian breeding populations

USGS Publications Warehouse

Wilson, Robert E.; Gust, J R; Petersen, Margaret; Talbot, Sandra L.

2016-01-01

Arctic ecosystems are changing at an unprecedented rate. How Arctic species are able to respond to such environmental change is partially dependent on the connections between local and broadly distributed populations. For species like the Long-tailed Duck (Clangula hyemalis), we have limited telemetry and band-recovery information from which to infer population structure and migratory connectivity; however, genetic analyses can offer additional insights. To examine population structure in the Long-tailed Duck, we characterized variation at mtDNA control region and microsatellite loci among four breeding areas in Alaska, Canada, and Russia. We observed significant differences in the variance of mtDNA haplotype frequencies between the Yukon-Kuskokwim Delta (YKD) and the three Arctic locations (Arctic Coastal Plain in Alaska, eastern Siberia, and central Canadian Arctic). However, like most sea duck genetic assessments, our study found no evidence of population structure based on autosomal microsatellite loci. Long-tailed Ducks use multiple wintering areas where pair formation occurs with some populations using both the Pacific and Atlantic Oceans. This situation provides a greater opportunity for admixture across breeding locales, which would likely homogenize the nuclear genome even in the presence of female philopatry. The observed mtDNA differentiation was largely due to the presence of two divergent clades: (A) a clade showing signs of admixture among all breeding locales and (B) a clade primarily composed of YKD samples. We hypothesize that the pattern of mtDNA differentiation reflects some degree of philopatry to the YKD and isolation of two refugial populations with subsequent expansion and admixture. We recommend additional genetic assessments throughout the circumpolar range of Long-tailed Ducks to further quantify aspects of genetic diversity and migratory connectivity in this species.

Ship-based Observations of Atmospheric Black Carbon Particles over the Arctic Ocean, Bering Sea, and North Western Pacific Ocean on 2016: Comparisons with Regional Chemical Transport Model simulations

NASA Astrophysics Data System (ADS)

Taketani, F.; Miyakawa, T.; Takigawa, M.; Yamaguchi, M.; Kanaya, Y.; Komazaki, Y.; Takashima, H.; Mordovskoi, P.; Tohjima, Y.

2017-12-01

Black carbon (BC), formed through the incomplete combustion of fossil fuels, biofuels, and biomass, is a major component of light-absorbing particulate matter in the atmosphere, causing positive radiative forcing. Also, BC deposition on the surface reduces the Earth's albedo and accelerates snow/ice melting by absorbing the sunlight. Therefore, the impact of BC on the Arctic climate needs to be assessed; however, observational information has been still insufficient. Over the Arctic Ocean, we have been conducting ship-based BC observations using a single particle soot photometer (SP2) on R/V Mirai every summer since 2014. To estimate the transport pathways of BC, we have also conducted model simulations during the period of cruise using a regional transport model (WRF-Chem 3.8.1). Here we focus on observations conducted on-board the R/V Mirai from 22 August to 5 October 2016 in a round trip to the Arctic Ocean through the Bering Strait from a port of Hachinohe (40.52N, 141.51E), Japan. We captured relatively high BC mass concentration events in this observation. The observed average BC mass concentration during 2016 was 0.8 ± 1.4 ng/m3 in >70N, similar to the levels ( 1.0ng/m3) recorded during our previous observations in the Arctic during 2014 and 2015. The variations in the observed concentrations in 2016 were qualitatively well reproduced by the regional chemical transport model. Quantitatively, however, the model tended to overestimate the BC levels, suggesting the possibilities that the emission rates were overestimated and/or the removal rates were underestimated. We will present further analysis on the size distribution, coating, and possible sources.

Ontogenetic, spatial and temporal variation in trophic level and diet of Chukchi Sea fishes

NASA Astrophysics Data System (ADS)

Marsh, Jennifer M.; Mueter, Franz J.; Iken, Katrin; Danielson, Seth

2017-01-01

Climate warming and increasing development are expected to alter the ecosystem of the Chukchi Sea, including its fish communities. As a component of the Arctic Ecosystem Integrated Survey, we assessed the ontogenetic, spatial and temporal variability of the trophic level and diet of key fish species in the Chukchi Sea using N and C stable isotopes. During August and September of 2012 and 2013, 16 common fish species and two primary, invertebrate consumers were collected from surface, midwater and bottom trawls within the eastern Chukchi Sea. Linear mixed-effects models were used to detect possible variation in the relationship between body length and either δ13C or δ15N values among water masses and years for 13 fish species with an emphasis on Arctic cod (Boreogadus saida). We also examined the fish community isotopic niche space, trophic redundancy, and trophic separation within each water mass as measures of resiliency of the fish food web. Ontogenetic shifts in trophic level and diet were observed for most species and these changes tended to vary by water mass. As they increased in length, most fish species relied more on benthic prey with the exception of three forage fish species (walleye pollock, Gadus chalcogrammus, capelin, Mallotus villosus, and Pacific sandlance, Ammodytes hexapterus). Species that exhibited interannual differences in diet and trophic level were feeding at lower trophic levels and consumed a more pelagic diet in 2012 when zooplankton densities were higher. Fish communities occupied different isotopic niche spaces depending on water mass association. In more northerly Arctic waters, the fish community occupied the smallest isotopic niche space and relied heavily on a limited range of intermediate δ13C prey, whereas in warmer, nutrient-rich Bering Chukchi Summer Water, pelagic prey was important. In the warmest, Pacific-derived coastal water, fish consumed both benthic and pelagic prey. Examining how spatial gradients in trophic position are linked to environmental drivers can provide insight into potential fish community shifts with a changing climate.

Large Scale Variability of Phytoplankton Blooms in the Arctic and Peripheral Seas: Relationships with Sea Ice, Temperature, Clouds, and Wind

NASA Technical Reports Server (NTRS)

Comiso, Josefino C.; Cota, Glenn F.

2004-01-01

Spatially detailed satellite data of mean color, sea ice concentration, surface temperature, clouds, and wind have been analyzed to quantify and study the large scale regional and temporal variability of phytoplankton blooms in the Arctic and peripheral seas from 1998 to 2002. In the Arctic basin, phytoplankton chlorophyll displays a large symmetry with the Eastern Arctic having about fivefold higher concentrations than those of the Western Arctic. Large monthly and yearly variability is also observed in the peripheral seas with the largest blooms occurring in the Bering Sea, Sea of Okhotsk, and the Barents Sea during spring. There is large interannual and seasonal variability in biomass with average chlorophyll concentrations in 2002 and 2001 being higher than earlier years in spring and summer. The seasonality in the latitudinal distribution of blooms is also very different such that the North Atlantic is usually most expansive in spring while the North Pacific is more extensive in autumn. Environmental factors that influence phytoplankton growth were examined, and results show relatively high negative correlation with sea ice retreat and strong positive correlation with temperature in early spring. Plankton growth, as indicated by biomass accumulation, in the Arctic and subarctic increases up to a threshold surface temperature of about 276-277 degree K (3-4 degree C) beyond which the concentrations start to decrease suggesting an optimal temperature or nutrient depletion. The correlation with clouds is significant in some areas but negligible in other areas, while the correlations with wind speed and its components are generally weak. The effects of clouds and winds are less predictable with weekly climatologies because of unknown effects of averaging variable and intermittent physical forcing (e.g. over storm event scales with mixing and upwelling of nutrients) and the time scales of acclimation by the phytoplankton.

McCall Glacier record of Arctic climate change: Interpreting a northern Alaska ice core with regional water isotopes

NASA Astrophysics Data System (ADS)

Klein, E. S.; Nolan, M.; McConnell, J.; Sigl, M.; Cherry, J.; Young, J.; Welker, J. M.

2016-01-01

We explored modern precipitation and ice core isotope ratios to better understand both modern and paleo climate in the Arctic. Paleoclimate reconstructions require an understanding of how modern synoptic climate influences proxies used in those reconstructions, such as water isotopes. Therefore we measured periodic precipitation samples at Toolik Lake Field Station (Toolik) in the northern foothills of the Brooks Range in the Alaskan Arctic to determine δ18O and δ2H. We applied this multi-decadal local precipitation δ18O/temperature regression to ∼65 years of McCall Glacier (also in the Brooks Range) ice core isotope measurements and found an increase in reconstructed temperatures over the late-20th and early-21st centuries. We also show that the McCall Glacier δ18O isotope record is negatively correlated with the winter bidecadal North Pacific Index (NPI) climate oscillation. McCall Glacier deuterium excess (d-excess, δ2H - 8*δ18O) values display a bidecadal periodicity coherent with the NPI and suggest shifts from more southwestern Bering Sea moisture sources with less sea ice (lower d-excess values) to more northern Arctic Ocean moisture sources with more sea ice (higher d-excess values). Northern ice covered Arctic Ocean McCall Glacier moisture sources are associated with weak Aleutian Low (AL) circulation patterns and the southern moisture sources with strong AL patterns. Ice core d-excess values significantly decrease over the record, coincident with warmer temperatures and a significant reduction in Alaska sea ice concentration, which suggests that ice free northern ocean waters are increasingly serving as terrestrial precipitation moisture sources; a concept recently proposed by modeling studies and also present in Greenland ice core d-excess values during previous transitions to warm periods. This study also shows the efficacy and importance of using ice cores from Arctic valley glaciers in paleoclimate reconstructions.

The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation

PubMed Central

Cózar, Andrés; Martí, Elisa; Duarte, Carlos M.; García-de-Lomas, Juan; van Sebille, Erik; Ballatore, Thomas J.; Eguíluz, Victor M.; González-Gordillo, J. Ignacio; Pedrotti, Maria L.; Echevarría, Fidel; Troublè, Romain; Irigoien, Xabier

2017-01-01

The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources. In the present study, the Arctic Ocean was extensively sampled for floating plastic debris from the Tara Oceans circumpolar expedition. Although plastic debris was scarce or absent in most of the Arctic waters, it reached high concentrations (hundreds of thousands of pieces per square kilometer) in the northernmost and easternmost areas of the Greenland and Barents seas. The fragmentation and typology of the plastic suggested an abundant presence of aged debris that originated from distant sources. This hypothesis was corroborated by the relatively high ratios of marine surface plastic to local pollution sources. Surface circulation models and field data showed that the poleward branch of the Thermohaline Circulation transfers floating debris from the North Atlantic to the Greenland and Barents seas, which would be a dead end for this plastic conveyor belt. Given the limited surface transport of the plastic that accumulated here and the mechanisms acting for the downward transport, the seafloor beneath this Arctic sector is hypothesized as an important sink of plastic debris. PMID:28439534

The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation.

PubMed

Cózar, Andrés; Martí, Elisa; Duarte, Carlos M; García-de-Lomas, Juan; van Sebille, Erik; Ballatore, Thomas J; Eguíluz, Victor M; González-Gordillo, J Ignacio; Pedrotti, Maria L; Echevarría, Fidel; Troublè, Romain; Irigoien, Xabier

2017-04-01

The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources. In the present study, the Arctic Ocean was extensively sampled for floating plastic debris from the Tara Oceans circumpolar expedition. Although plastic debris was scarce or absent in most of the Arctic waters, it reached high concentrations (hundreds of thousands of pieces per square kilometer) in the northernmost and easternmost areas of the Greenland and Barents seas. The fragmentation and typology of the plastic suggested an abundant presence of aged debris that originated from distant sources. This hypothesis was corroborated by the relatively high ratios of marine surface plastic to local pollution sources. Surface circulation models and field data showed that the poleward branch of the Thermohaline Circulation transfers floating debris from the North Atlantic to the Greenland and Barents seas, which would be a dead end for this plastic conveyor belt. Given the limited surface transport of the plastic that accumulated here and the mechanisms acting for the downward transport, the seafloor beneath this Arctic sector is hypothesized as an important sink of plastic debris.

Afghan National Police Training Program Would Benefit from Better Compliance with the Economy Act and Reimbursable Agreements

DTIC Science & Technology

2011-08-25

Security Cooperation Agency INL Bureau of International Narcotics and Law Enforcement Affairs JSSP Justice Sector Security Program PAE Pacific...regional training centers. The programs were the Justice Sector Security Program ( JSSP ), the Corrections System Support Program (CSSP), and the...Civilian Police International. JSSP and CSSP are considered rule of law programs. Rule of law is most commonly understood to be a foundational

Comparing Diverse Southeast Asian Reactions to the Trans-Pacific Partnership (TPP)

DTIC Science & Technology

2017-09-01

The ambitious TPP comes with its own set of challenges. Especially in the agricultural sector and in the area of intellectual property, domestic...favor of high-quality comprehensive FTAs, save for stalled negotiations in provisions on the agricultural sector due to the domestic political...strength and influence of the Ministry of Agriculture , Forestry and Fisheries.16 Capling and Ravenhill note that although the United States succeeded in

Long-Term Geochemical and Geodynamic Segmentation of the Paleo-Pacific Margin of Gondwana: Insight From the Antarctic and Adjacent Sectors

NASA Astrophysics Data System (ADS)

Nelson, D. A.; Cottle, J. M.

2017-12-01

Combined zircon geochemistry and geochronology of Mesozoic volcaniclastic sediments of the central Transantarctic Mountains, Antarctica, yield a comprehensive record of both the timing and geochemical evolution of the magmatic arc along the Antarctic sector of the paleo-Pacific margin of Gondwana. Zircon age populations at 266-183 Ma, 367-328 Ma, and 550-490 Ma correspond to episodic arc activity from the Ediacaran to the Jurassic. Zircon trace element geochemistry indicates a temporal shift from granitoid-dominated source(s) during Ediacaran to Early Ordovician times to mafic sources in the Devonian through Early Jurassic. Zircon initial ɛHf shifts to more radiogenic Hf isotope compositions following the Ross Orogeny and is inferred to reflect juvenile crustal growth within an extensional arc system during progressive slab rollback. These new ages and Hf isotopic record are similar to those from the Australian sector, indicating that these regions constituted an 3,000 km laterally continuous extensional arc from at least the Carboniferous to the Permian. Conversely, the South American sector records enriched zircon Hf isotopic compositions and compressional/advancing arc tectonics during the same time period. Our new data constrain the location of this profound along-arc geochemical and geodynamic "switch" to the vicinity of the Thurston Island block of West Antarctica.

SEASAT views oceans and sea ice with synthetic aperture radar

NASA Technical Reports Server (NTRS)

Fu, L. L.; Holt, B.

1982-01-01

Fifty-one SEASAT synthetic aperture radar (SAR) images of the oceans and sea ice are presented. Surface and internal waves, the Gulf Stream system and its rings and eddies, the eastern North Pacific, coastal phenomena, bathymetric features, atmospheric phenomena, and ship wakes are represented. Images of arctic pack and shore-fast ice are presented. The characteristics of the SEASAT SAR system and its image are described. Maps showing the area covered, and tables of key orbital information, and listing digitally processed images are provided.

NABOS-II Observational Program in the Arctic Ocean: New Perspectives and New Challenges

NASA Astrophysics Data System (ADS)

Ivanov, V.; Polyakov, I.; Ashik, I. M.; Pnyushkov, A.; Alkire, M. B.; Repina, I.; Alexeev, V. A.; Waddington, I.; Kanzow, T.; Goszczko, I.; Rember, R.; Artamonov, A.

2016-02-01

NABOS-II observational program was launched in 2013 on the basis of new knowledge obtained during NABOS (=Nansen and Amundsen Basins Observations System) project back in 2000s. Up to now two large scale expeditions in the Eurasian sector of the Arctic Ocean were carried out in framework of NABOS-II: in 2013 and in 2015. These field studies were conducted by International Arctic Research Center (IARC) University of Alaska Fairbanks, USA in partnership with Arctic and Antarctic Research Institute (AARI) St.Petersburg Russia. The main goal of the NABOS-II project is to provide quantitative assessment of circulation and water mass transformation along the principal pathways transporting water from the Nordic Seas to the Arctic Basin under conditions of substantially reduced summer ice cover. Reduced sea ice causes changes in the water column and in the overlying atmosphere. Documenting of these changes was the main target of the NABOS-II cruises. The scope of this goal and the opportunities of extended scientific research in the Arctic, provided during NABOS expeditions, encouraged scientific institutions from the USA, Europe and Asia to raise funds, contribute to the cruise program and to send their personnel to expeditions, thus giving them a true multidisciplinary status. The ambitious mission of collecting a two year long time series of hydrographic data at 6 moorings along 126E meridian from the upper slope (250 m depth) to the deep basin (3900 m depth) in the Laptev Sea was successfully accomplished in 2015. The collected data are truly unique, since they shed new light on the structure and spatio-temporal variability of water properties and transports in the Lapev Sea, which is the key region for understanding of interaction between Atlantic water branches. This presentation describes preliminary results of performed analysis.

NABOS-II Observational Program in the Arctic Ocean: New Perspectives and new Challenges

NASA Astrophysics Data System (ADS)

Ivanov, Vladimir; Polyakov, Igor; Ashik, Igor; Pnyushkov, Andrey; Alkire, Matthew; Repina, Irina; Alexeev, Vladimir; Waddington, Ian; Kanzow, Torsten; Rember, Robert; Artamonov, Alexander; Goszczko, Ilona

2016-04-01

NABOS-II observational program was launched in 2013 on the basis of new knowledge obtained during NABOS (=Nansen and Amundsen Basins Observations System) project back in 2000s. Up to now two large scale expeditions in the Eurasian sector of the Arctic Ocean were carried out in framework of NABOS-II: in 2013 and in 2015. These field studies were conducted by International Arctic Research Center (IARC) University of Alaska Fairbanks, USA in partnership with Arctic and Antarctic Research Institute (AARI) St.Petersburg Russia. The main goal of the NABOS-II project is to provide quantitative assessment of circulation and water mass transformation along the principal pathways transporting water from the Nordic Seas to the Arctic Basin under conditions of substantially reduced summer ice cover. Reduced sea ice causes changes in the water column and in the overlying atmosphere. Documenting of these changes was the main target of the NABOS-II cruises. The scope of this goal and the opportunities of extended scientific research in the Arctic, provided during NABOS expeditions, encouraged scientific institutions from the USA, Europe and Asia to raise funds, contribute to the cruise program and to send their personnel to expeditions, thus giving them a true multidisciplinary status. The ambitious mission of collecting a two year long time series of hydrographic data at 6 moorings along 126E meridian from the upper slope (250 m depth) to the deep basin (3900 m depth) in the Laptev Sea was successfully accomplished in 2015. The collected data are truly unique, since they shed new light on the structure and spatio-temporal variability of water properties and transports in the Lapev Sea, which is the key region for understanding of interaction between Atlantic water branches. This presentation describes preliminary results of performed analysis.

An assessment of national surveillance systems for malaria elimination in the Asia Pacific.

PubMed

Mercado, Chris Erwin G; Ekapirat, Nattwut; Dondorp, Arjen M; Maude, Richard J

2017-03-21

Heads of Government from Asia and the Pacific have committed to a malaria-free region by 2030. In 2015, the total number of confirmed cases reported to the World Health Organization by 22 Asia Pacific countries was 2,461,025. However, this was likely a gross underestimate due in part to incidence data not being available from the wide variety of known sources. There is a recognized need for an accurate picture of malaria over time and space to support the goal of elimination. A survey was conducted to gain a deeper understanding of the collection of malaria incidence data for surveillance by National Malaria Control Programmes in 22 countries identified by the Asia Pacific Leaders Malaria Alliance. In 2015-2016, a short questionnaire on malaria surveillance was distributed to 22 country National Malaria Control Programmes (NMCP) in the Asia Pacific. It collected country-specific information about the extent of inclusion of the range of possible sources of malaria incidence data and the role of the private sector in malaria treatment. The findings were used to produce recommendations for the regional heads of government on improving malaria surveillance to inform regional efforts towards malaria elimination. A survey response was received from all 22 target countries. Most of the malaria incidence data collected by NMCPs originated from government health facilities, while many did not collect comprehensive data from mobile and migrant populations, the private sector or the military. All data from village health workers were included by 10/20 countries and some by 5/20. Other sources of data included by some countries were plantations, police and other security forces, sentinel surveillance sites, research or academic institutions, private laboratories and other government ministries. Malaria was treated in private health facilities in 19/21 countries, while anti-malarials were available in private pharmacies in 16/21 and private shops in 6/21. Most countries use primarily paper-based reporting. Most collected malaria incidence data in the Asia Pacific is from government health facilities while data from a wide variety of other known sources are often not included in national surveillance databases. In particular, there needs to be a concerted regional effort to support inclusion of data on mobile and migrant populations and the private sector. There should also be an emphasis on electronic reporting and data harmonization across organizations. This will provide a more accurate and up to date picture of the true burden and distribution of malaria and will be of great assistance in helping realize the goal of malaria elimination in the Asia Pacific by 2030.

Incentives for retaining and motivating health workers in Pacific and Asian countries.

PubMed

Henderson, Lyn N; Tulloch, Jim

2008-09-15

This paper was initiated by the Australian Agency for International Development (AusAID) after identifying the need for an in-depth synthesis and analysis of available literature and information on incentives for retaining health workers in the Asia-Pacific region. The objectives of this paper are to: 1. Highlight the situation of health workers in Pacific and Asian countries to gain a better understanding of the contributing factors to health worker motivation, dissatisfaction and migration. 2. Examine the regional and global evidence on initiatives to retain a competent and motivated health workforce, especially in rural and remote areas. 3. Suggest ways to address the shortages of health workers in Pacific and Asian countries by using incentives. The review draws on literature and information gathered through a targeted search of websites and databases. Additional reports were gathered through AusAID country offices, UN agencies, and non-government organizations. The severe shortage of health workers in Pacific and Asian countries is a critical issue that must be addressed through policy, planning and implementation of innovative strategies--such as incentives--for retaining and motivating health workers. While economic factors play a significant role in the decisions of workers to remain in the health sector, evidence demonstrates that they are not the only factors. Research findings from the Asia-Pacific region indicate that salaries and benefits, together with working conditions, supervision and management, and education and training opportunities are important. The literature highlights the importance of packaging financial and non-financial incentives. Each country facing shortages of health workers needs to identify the underlying reasons for the shortages, determine what motivates health workers to remain in the health sector, and evaluate the incentives required for maintaining a competent and motivated health workforce. Decision-making factors and responses to financial and non-financial incentives have not been adequately monitored and evaluated in the Asia-Pacific region. Efforts must be made to build the evidence base so that countries can develop appropriate workforce strategies and incentive packages.

Diet analysis of Alaska Arctic snow crabs (Chionoecetes opilio) using stomach contents and δ13C and δ15N stable isotopes

NASA Astrophysics Data System (ADS)

Divine, Lauren M.; Bluhm, Bodil A.; Mueter, Franz J.; Iken, Katrin

2017-01-01

We used stomach content and stable δ13C and δ15N isotope analyses to investigate male and female snow crab diets over a range of body sizes (30-130 mm carapace width) in five regions of the Pacific Arctic (southern and northern Chukchi Sea, western, central, and Canadian Beaufort Sea). Snow crab stomach contents from the southern Chukchi Sea were also compared to available prey biomass and abundance. Snow crabs consumed four main prey taxa: polychaetes, decapod crustaceans (crabs, amphipods), echinoderms (mainly ophiuroids), and mollusks (bivalves, gastropods). Both approaches revealed regional differences. Crab diets in the two Chukchi regions were similar to those in the western Beaufort (highest bivalve, amphipod, and crustacean consumption). The Canadian Beaufort region was most unique in prey composition and in stable isotope values. We also observed a trend of decreasing carbon stable isotopes in crabs from the Chukchi to those in the Canadian Beaufort, likely reflecting the increasing use of terrestrial carbon sources towards the eastern regions of the Beaufort Sea from Mackenzie River influx. Cannibalism on snow crabs was higher in the Chukchi regions relative to the Beaufort regions. We suggest that cannibalism may have an impact on recruitment in the Chukchi Sea via reduction of cohort strength after settlement to the benthos, as known from the Canadian Atlantic. Prey composition varied with crab size only in some size classes in the southern Chukchi and central Beaufort, while stable isotope results showed no size-dependent differences. Slightly although significantly higher mean carbon isotope values for males in the southern Chukchi may not be reflective of a gender-specific pattern but rather be driven by low sample size. Finally, the lack of prey selection relative to availability in crabs in the southern Chukchi suggests that crabs consume individual prey taxa in relative proportions to prey field abundances. The present study is the first to provide a baseline of the omnivorous role of snow crabs across the entire Pacific Arctic, as well as evidence for cannibalism in the Chukchi Sea. In light of climate change predictions for the Alaska Arctic, and the potential for future fisheries harvest of snow crabs in this region, continued monitoring of snow crabs, including population and trophic dynamics, is increasingly important to assess snow crab impacts on benthic communities and vice versa.

What Happens when Sea Ice Retreats, Peatlands Form, and a Landbridge Drowns? A Molecular View of the Last Deglacial from the Pacific-Arctic Gateway

NASA Astrophysics Data System (ADS)

Kocis, J. J.; Petsch, S.; Castañeda, I. S.; Brigham-Grette, J.

2014-12-01

Arctic peatlands and thermokarst lakes (TK) are thought to play a significant role in changing atmospheric methane concentration (AMC) during the last deglacial. However, there is debate concerning timing of their initiation and extent they drove variations in AMC. Models show sea ice cover (SIC) and sea surface temperatures (SSTs) can also play a significant role. Yet, changes in peatland/TK lake areal extent in response to those dynamics as continental shelves were submerged are often not considered. To examine such connections, we report on molecular proxies in marine records that reveal change in terrestrial organic matter (TOM) export, SIC, and SSTs as sea levels rose during the last 18 ka in the Pacific-Arctic Gateway. Here, TOM input to the ocean was tracked by measuring the flux of branched glycerol dialkyl glycerol tetraethers, n-alkyl lipids, and pentacyclic triterpenoids. SIC and SSTs were reconstructed using modern calibrations of highly branched isoprenoid alkene abundances in surface sediments from the Bering and Chukchi Seas. SSTs were also reconstructed based on the relative abundance of isoprenoid glycerol dialkyl glycerol tetraethers. Our sediment records reveal increased flux of TOM coincides with peatland/TK lake initiation, reduced SIC (~20%), and warmer SSTs (~4°C) as AMC increased during the Bølling-Allerød (BA). Terrestrial flux dramatically reduced as SIC increased (~50%) and SSTs cooled as AMC fell during the Younger Dryas. Most notably, TOM export rapidly rebounds as AMC abruptly rose throughout the Holocene Thermal Maximum (HTM), when SSTs warmed by ~3°C and SIC diminished and peatland areal extent increased. Using multi-proxy evidence in combination with a simple model that accounts for submergence of peatland/TK lake area, we estimate that the exposed Beringian shelf emitted an amount of CH4 comparable to previously reported peatland emissions in Alaska during the BA and HTM. The GDGT-based methane index (MI) was <0.3 throughout our sediment records, suggesting destabilized marine gas hydrates were not the principal source of methane. Results of our study provide novel marine-based evidence for the timing of peatland and TK lake initiation and the role sea ice played in contributing to variations in AMC during deglacial sea level rise in the Arctic.

Sedimentation in the Lena river delta and adjacent part of the Laptev Sea

NASA Astrophysics Data System (ADS)

Charkin, A.; Dudarev, O.; Semiletov, I.; Vonk, J.; Sanchez-Garcia, L.; Gustafsson, Ö.; Andersson, P.; Shakhova, N.

2009-04-01

Any attempt to understand the effects of the Arctic Ocean on global change or the effect of global change on the Arctic Ocean requires a thorough understanding of coastal processes. The major transport of freshwater, dissolved and solid materials into the Arctic ocean is determined by riverine discharge and coastal erosion from Eurasia . The Lena River drains almost 3 mill. km2 of the vast Siberian hinterland (which is now under strong warming impact), and discharge up to 720 km3 per year, making it the second largest river draining into the Arctic Ocean. Thus, it is extremely important to perform a base-line study in the key area of the near-shore Arctic ocean which integrates Lena River discharge, which is a product o permafrost degradation in the Lena watershed, and off-shore export of eroded material, which is mostly induced by retreatment of the coastal ice-complex. Since 1999, the Buor-Khaya Gulf was chosen for detailed investigation by Laboratory of the Arctic Research (LAR) of the Pacific Oceanological Institute as a key area which accepts both eroded carbon and solid discharge from the Bykovsky and Bol'shay/Malaya Trofimovsky channels of the Lena delta. The intention of this report is to present a first comprehensive interpretation of the modern depositional environment in the Lena river delta and Buor-Khaya Gulf considering all the geochemical data obtained both in the International Siberian Shelf Study2008 (ISSS-08) and 11 previous summertime and wintertime LAR expeditions (1999-2007), accomplished in cooperation with the International Arctic Research Center of the University Alaska Fairbanks. Set of samples was studied in cooperation with the Stockholm University and Swedish Museum of Natural History. Detailed transects and maps of the particulate material distribution, particulate organic carbon (POC) and nitrogen (PON) as well as CN stable isotopes in both suspended particles and underlying surface sediment, and its sizing are discussed in connection with changing hydrometeorological conditions with a special emphasis on the area surrounding Muostakh Island, which exhibits rates of coastal erosion up to 15-20 m during couple summertime weeks.

Landsat time series analysis documents beaver migration into permafrost landscapes of arctic Alaska

NASA Astrophysics Data System (ADS)

Jones, B. M.; Tape, K. D.; Nitze, I.; Arp, C. D.; Grosse, G.; Zimmerman, C. E.

2017-12-01

Landscape-scale impacts of climate change in the Arctic include increases in growing season length, shrubby vegetation, winter river discharge, snowfall, summer and winter water temperatures, and decreases in river and lake ice thickness. Combined, these changes may have created conditions that are suitable for beaver colonization of low Arctic tundra regions. We developed a semi-automated workflow that analyzes Landsat imagery time series to determine the extent to which beavers may have colonized permafrost landscapes in arctic Alaska since 1999. We tested this approach on the Lower Noatak, Wulik, and Kivalina river watersheds in northwest Alaska and identified 83 locations representing potential beaver activity. Seventy locations indicated wetting trends and 13 indicated drying trends. Verification of each site using high-resolution satellite imagery showed that 80 % of the wetting locations represented beaver activity (damming and pond formation), 11 % were unrelated to beavers, and 9 % could not readily be distinguished as being beaver related or not. For the drying locations, 31 % represented beaver activity (pond drying due to dam abandonment), 62 % were unrelated to beavers, and 7 % were undetermined. Comparison of the beaver activity database with historic aerial photography from ca. 1950 and ca. 1980 indicates that beavers have recently colonized or recolonized riparian corridors in northwest Alaska. Remote sensing time series observations associated with the migration of beavers in permafrost landscapes in arctic Alaska include thermokarst lake expansion and drainage, thaw slump initiation, ice wedge degradation, thermokarst shore fen development, and possibly development of lake and river taliks. Additionally, beaver colonization in the Arctic may alter channel courses, thermal regimes, hyporheic flow, riparian vegetation, and winter ice regimes that could impact ecosystem structure and function in this region. In particular, the combination of beaver activity and permafrost dynamics may play an important role in the formation of habitats conducive to colonization by Pacific salmon. Beaver activity in arctic tundra regions may amplify the effects of climate change on permafrost landscapes and lead to landscape-scale responses not currently being considered in ecosystem models.

Trends of Cyclone Characteristics in the Arctic and Their Patterns From Different Reanalysis Data

NASA Astrophysics Data System (ADS)

Zahn, Matthias; Akperov, Mirseid; Rinke, Annette; Feser, Frauke; Mokhov, Igor I.

2018-03-01

Cyclones in the Arctic are detected and tracked in four different reanalysis data sets from 1981 to 2010. In great detail the spatial and seasonal patterns of changes are scrutinized with regards to their frequencies, depths, and sizes. We find common spatial patterns for their occurrences, with centers of main activity over the seas in winter, and more activity over land and over the North Pole in summer. The deep cyclones are more frequent in winter, and the number of weak cyclones peaks in summer. Overall, we find a good agreement of our tracking results across the different reanalyses. Regarding the frequency changes, we find strong decreases in the Barents Sea and along the Russian coast toward the North Pole and increases over most of the central Arctic Ocean and toward the Pacific in winter. Areas of increasing and decreasing frequencies are of similar size in winter. In summer there is a longish region of increase from the Laptev Sea toward Greenland, over the Canadian archipelago, and over some smaller regions west of Novaya Zemlya and over the Russia. The larger part of the Arctic experiences a frequency decrease. All the summer changes are found statistically unrelated to the winter patterns. In addition, the frequency changes are found unrelated to changes in cyclone depth and size. There is generally good agreement across the different reanalyses in the spatial patterns of the trend sign. However, the magnitudes of changes in a particular region may strongly differ across the data.

Downscaled ice-ocean simulations for the Chukchi and Eastern Siberian Seas from an oceanic re-analysis product

NASA Astrophysics Data System (ADS)

Fujisaki-Manome, A.; Wang, J.

2016-12-01

Arctic summer sea ice has been declining at the rate that is much faster than any climate models predict. While the accelerated sea ice melting in the recent few decades could be attributed to several mechanisms such as the Arctic temperature amplification and the ice-albedo feedback, this does not necessarily explain why climate models underestimate the observed rate of summer sea ice loss. Clearly, an improved understanding is needed in what processes could be missed in climate models and could play roles in unprecedented loss of sea ice. This study evaluates contributions of sub-mesoscale processes in the ice edge (i.e. the boundary region between open water and ice covered area), which include eddies, ice bands, and the vertical mixing associated with ice bands, to the melting of sea ice and how they explain the underestimation of sea ice loss in the current state-of-art climate models. The focus area is in the pacific side of the Arctic Ocean. First, several oceanic re-analysis products including NCEP-Climate Forecast System Reanalysis (CFSR) and Modern-Era Retrospective Analysis for Research and Applications (MERRA) are evaluated in comparison with the in-situ observations from the Russian-American Long-term Census of the Arctic (RUSALCA) project. Second, the downscaled ice-ocean simulations are conducted for the Chukchi and East Siberian Seas with initial and open boundary conditions provided from a selected oceanic re-analysis product.

Large Eddy Simulation of Heat Entrainment Under Arctic Sea Ice

NASA Astrophysics Data System (ADS)

Ramudu, Eshwan; Gelderloos, Renske; Yang, Di; Meneveau, Charles; Gnanadesikan, Anand

2018-01-01

Arctic sea ice has declined rapidly in recent decades. The faster than projected retreat suggests that free-running large-scale climate models may not be accurately representing some key processes. The small-scale turbulent entrainment of heat from the mixed layer could be one such process. To better understand this mechanism, we model the Arctic Ocean's Canada Basin, which is characterized by a perennial anomalously warm Pacific Summer Water (PSW) layer residing at the base of the mixed layer and a summertime Near-Surface Temperature Maximum (NSTM) within the mixed layer trapping heat from solar radiation. We use large eddy simulation (LES) to investigate heat entrainment for different ice-drift velocities and different initial temperature profiles. The value of LES is that the resolved turbulent fluxes are greater than the subgrid-scale fluxes for most of our parameter space. The results show that the presence of the NSTM enhances heat entrainment from the mixed layer. Additionally there is no PSW heat entrained under the parameter space considered. We propose a scaling law for the ocean-to-ice heat flux which depends on the initial temperature anomaly in the NSTM layer and the ice-drift velocity. A case study of "The Great Arctic Cyclone of 2012" gives a turbulent heat flux from the mixed layer that is approximately 70% of the total ocean-to-ice heat flux estimated from the PIOMAS model often used for short-term predictions. Present results highlight the need for large-scale climate models to account for the NSTM layer.

Influence of SST anomalies in low latitudes on atmospheric heat transport to the Arctic

NASA Astrophysics Data System (ADS)

Alekseev, Genrikh; Kuzmina, Svetlana; Glok, Natalia

2017-04-01

The purpose of the study is to assess the influence of SST anomalies in the low latitudes of the Atlantic, Indian and Pacific oceans to climatic change of the winter atmospheric meridional heat transport (MAHT) to the Arctic and to propose the mechanisms of this influence. Estimates of sensible and latent heat transport to the Arctic through the "Atlantic Gate" at 70 ° N in winter (December-February) 1980-2015 fulfilled on base ERA / Interim and monthly SST from HadISST were used. Multi-dimensional cross-correlation analysis was applied. The area and month in each ocean were found with maximal correlations between SST and winter MAHT. Mean SST in selected areas for each month of 1980-2015 were calculated and its correlations with MAHT were estimated. The correlation coefficients equal from 0.57 to 0.42, and after removing the noise increased up to 0.75 with MAHT lag from 27 to 30 months. The SST and MAHT series include together with positive trend the 5-7 years fluctuations. The mechanism of SST anomalies influence on winter MAHT to the Arctic includes the interaction of atmospheric (Hadley and Ferrel circulations, jet streams, NAO) and oceanic (Gulf Stream, the North Atlantic, the Norwegian currents) circulation patterns. To justify the proposed scheme the evaluation of the links between SST anomalies, the NAO index, the Atlantic water inflow to the Barents Sea, are investigated. The study is supported with RFBR project 15-05-03512.

Three-Dimensional Numerical Simulations of Equatorial Spread F: Results and Observations in the Pacific Sector

NASA Technical Reports Server (NTRS)

Aveiro, H. C.; Hysell, D. L.; Caton, R. G.; Groves, K. M.; Klenzing, J.; Pfaff, R. F.; Stoneback, R.; Heelis, R. A.

2012-01-01

A three-dimensional numerical simulation of plasma density irregularities in the postsunset equatorial F region ionosphere leading to equatorial spread F (ESF) is described. The simulation evolves under realistic background conditions including bottomside plasma shear flow and vertical current. It also incorporates C/NOFS satellite data which partially specify the forcing. A combination of generalized Rayleigh-Taylor instability (GRT) and collisional shear instability (CSI) produces growing waveforms with key features that agree with C/NOFS satellite and ALTAIR radar observations in the Pacific sector, including features such as gross morphology and rates of development. The transient response of CSI is consistent with the observation of bottomside waves with wavelengths close to 30 km, whereas the steady state behavior of the combined instability can account for the 100+ km wavelength waves that predominate in the F region.

Total Solar Eclipse of 1997 March 9

NASA Technical Reports Server (NTRS)

Espenak, Fred; Anderson, Jay

1995-01-01

A total eclipse of the Sun will be visible from Asia and the Pacific Ocean on 1997 March 9. The path of the Moon's umbral shadow begins in eastern Kazakhstan and travels through Mongolia and eastern Siberia, where it swings northward to end at sunset in the Arctic Ocean. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes eastern Asia, the northern Pacific, and the northwest corner of North America. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 280 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Tips and suggestions are also given on how to safely view and photograph the eclipse.

Engaging new generation of Arctic researchers: 14 years and counting

NASA Astrophysics Data System (ADS)

Alexeev, V. A.; Walsh, J. E.; Hock, R.; Loucks, D. J.; Kaden, U.

2016-12-01

Today, more than ever, an integrated cross-disciplinary approach is necessary to explain changes in the Arctic and understand their implications for the human environment. Advanced training and active involvement of early-career scientists is an important component of this cross-disciplinary approach. This effort led by the International Arctic Research Center at the University of Alaska Fairbanks (UAF) started in 2003. The NSF supported project that started in 2013 conducted four summer schools (one per year) focused on four themes in four different Arctic locations. It provided the participants with an interdisciplinary perspective on Arctic change and its impacts on diverse sectors of the North. It is linked to other ongoing long-term observational and educational programs (e.g. NABOS, Nansen and Amundsen Basins Observational System; LTER, Long Term Environmental Research) and targets young scientists by using the interdisciplinary and place-based setting to broaden their perspective on Arctic change and to enhance their communication skills. Each course for 15-25 people consisted of classroom and hands-on components and work with a multidisciplinary group of mentors on projects devoted to themes exemplified by the location. A specialist from the School of Education at UAF evaluated student's progress during the summer schools. Additionally, an anthropologist attended the 2016 summer school to study how students learn to build and assess models, as well as examine students' and instructors' attitudes toward science communication, which provided additional feedback about learning and teaching in these settings. Lessons learned during the 14 years of conducting summer schools, methods of attracting in-kind support and approaches to teaching students are prominently featured in this study. Activities during the two most recent schools, one conducted at the Toolik Lake Field Station on the Alaskan North Slope and another at the International Arctic Research Center of the University of Alaska Fairbanks in 2016 is another focus of this work.

Philippines' downstream sector poised for growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-05-11

This paper reports that the Philippines' downstream sector is poised for sharp growth. Despite a slip in refined products demand in recent years, Philippines products demand will rebound sharply by 2000, East-West Center (EWC), Honolulu, predicts. Philippines planned refinery expansions are expected to meet that added demand, EWC Director Fereidun Fesharaki says. Like the rest of the Asia-Pacific region, product specifications are changing, but major refiners in the area expect to meet the changes without major case outlays. At the same time, Fesharaki says, push toward deregulation will further bolster the outlook for the Philippines downstream sector.

Population genetic structure in Atlantic and Pacific Ocean common murres (Uria aalge): Natural replicate tests of post-Pleistocene evolution

USGS Publications Warehouse

Morris-Pocock, J. A.; Taylor, S.A.; Birt, T.P.; Damus, M.; Piatt, John F.; Warheit, K.I.; Friesen, Vicki L.

2008-01-01

Understanding the factors that influence population differentiation in temperate taxa can be difficult because the signatures of both historic and contemporary demographics are often reflected in population genetic patterns. Fortunately, analyses based on coalescent theory can help untangle the relative influence of these historic and contemporary factors. Common murres (Uria aalge) are vagile seabirds that breed in the boreal and low arctic waters of the Northern Hemisphere. Previous analyses revealed that Atlantic and Pacific populations are genetically distinct; however, less is known about population genetic structure within ocean basins. We employed the mitochondrial control region, four microsatellite loci and four intron loci to investigate population genetic structure throughout the range of common murres. As in previous studies, we found that Atlantic and Pacific populations diverged during the Pleistocene and do not currently exchange migrants. Therefore, Atlantic and Pacific murre populations can be used as natural replicates to test mechanisms of population differentiation. While we found little population genetic structure within the Pacific, we detected significant east-west structuring among Atlantic colonies. The degree that population genetic structure reflected contemporary population demographics also differed between ocean basins. Specifically, while the low levels of population differentiation in the Pacific are at least partially due to high levels of contemporary gene flow, the east-west structuring of populations within the Atlantic appears to be the result of historic fragmentation of populations rather than restricted contemporary gene flow. The contrasting results in the Atlantic and Pacific Oceans highlight the necessity of carefully considering multilocus nonequilibrium population genetic approaches when reconstructing the demographic history of temperate Northern Hemisphere taxa. ?? 2008 The Authors.

Bering Sea Nd isotope records of North Pacific Intermediate Water circulation

NASA Astrophysics Data System (ADS)

Rabbat, C.; Knudson, K. P.; Goldstein, S. L.

2017-12-01

North Pacific Intermediate Water (NPIW) is the primary water mass associated with Pacific meridional overturning circulation. While the relationship between Atlantic meridional overturning circulation and climate has been extensively studied, a lack of suitable sediment cores has limited past investigations of North Pacific climate and NPIW variability. Integrated Ocean Drilling Program Site U1342 (818 m water depth) on Bower's Ridge in the Bering Sea is located at a sensitive depth for detecting changes in NPIW, and it is the only available sub-arctic North Pacific site that offers long, continuous core recovery, relatively high sedimentation rates, excellent foraminifera preservation, and a well-constrained age model over multiple glacial-interglacial cycles. Previous work at Site U1342 from Knudson and Ravelo (2015), using non-quantitative circulation proxies, provides evidence for enhanced NPIW formation during extreme glacials associated with the closure of the Bering Strait and suggest that NPIW was formed locally within the Bering Sea. Our work builds on the potential importance of these results and applies more robust and potentially quantitative circulation proxies to constrain NPIW variability. Here, we present new records of NPIW circulation from Site U1342 based on Nd isotope analyses on fish debris and Fe-Mn encrusted foraminifera, which serve as semi-quantitative "water mass tracers." Weak Bering Sea NPIW formation and ventilation are reflected by relatively lower eNd values indicative of open subarctic North Pacific waters, which are presently predominant, whereas enhanced Bering Sea NPIW formation and ventilation are be reflected by relatively higher eNd values due to the input of Nd from regional volcanic rocks.

Divergent movements of walrus and sea ice in the Nothern Bering Sea

USGS Publications Warehouse

Jay, Chadwick V.; Udevitz, Mark S.; Kwok, Ron; Fischbach, Anthony S.; Douglas, David C.

2010-01-01

The Pacific walrus Odobenus rosmarus divergens is a large Arctic pinniped of the Chukchi and Bering Seas. Reductions of sea ice projected to occur in the Arctic by mid-century raise concerns for conservation of the Pacific walrus. To understand the significance of sea ice loss to the viability of walruses, it would be useful to better understand the spatial associations between the movements of sea ice and walruses. We investigated whether local-scale (~1 to 100 km) walrus movements correspond to movements of sea ice in the Bering Sea in early spring, using locations from radio-tracked walruses and measures of ice floe movements from processed synthetic aperture radar satellite imagery. We used generalized linear mixed-effects models to analyze the angle between walrus and ice floe movement vectors and the distance between the final geographic position of walruses and their associated ice floes (displacement), as functions of observation duration, proportion of time the walrus was in water, and geographic region. Analyses were based on 121 walrus-ice vector pairs and observations lasting 12 to 36 h. Angles and displacements increased with observation duration, proportion of time the walrus spent in the water, and varied among regions (regional mean angles ranged from 40° to 81° and mean displacements ranged from 15 to 35 km). Our results indicated a lack of correspondence between walruses and their initially associated ice floes, suggesting that local areas of walrus activities were independent of the movement of ice floes.

Arctic Sea Ice Classification and Mapping for Surface Albedo Parameterization in Sea Ice Modeling

NASA Astrophysics Data System (ADS)

Nghiem, S. V.; Clemente-Colón, P.; Perovich, D. K.; Polashenski, C.; Simpson, W. R.; Rigor, I. G.; Woods, J. E.; Nguyen, D. T.; Neumann, G.

2016-12-01

A regime shift of Arctic sea ice from predominantly perennial sea ice (multi-year ice or MYI) to seasonal sea ice (first-year ice or FYI) has occurred in recent decades. This shift has profoundly altered the proportional composition of different sea ice classes and the surface albedo distribution pertaining to each sea ice class. Such changes impacts physical, chemical, and biological processes in the Arctic atmosphere-ice-ocean system. The drastic changes upset the traditional geophysical representation of surface albedo of the Arctic sea ice cover in current models. A critical science issue is that these profound changes must be rigorously and systematically observed and characterized to enable a transformative re-parameterization of key model inputs, such as ice surface albedo, to ice-ocean-atmosphere climate modeling in order to obtain re-analyses that accurately reproduce Arctic changes and also to improve sea ice and weather forecast models. Addressing this challenge is a strategy identified by the National Research Council study on "Seasonal to Decadal Predictions of Arctic Sea Ice - Challenges and Strategies" to replicate the new Arctic reality. We review results of albedo characteristics associated with different sea ice classes such as FYI and MYI. Then we demonstrate the capability for sea ice classification and mapping using algorithms developed by the Jet Propulsion Laboratory and by the U.S. National Ice Center for use with multi-sourced satellite radar data at L, C, and Ku bands. Results obtained with independent algorithms for different radar frequencies consistently identify sea ice classes and thereby cross-verify the sea ice classification methods. Moreover, field observations obtained from buoy webcams and along an extensive trek across Elson Lagoon and a sector of the Beaufort Sea during the BRomine, Ozone, and Mercury EXperiment (BROMEX) in March 2012 are used to validate satellite products of sea ice classes. This research enables the mapping of Arctic sea ice classes over multiple decades using multiple satellite radar datasets with both coarse resolution for synoptic scales and high resolution for local and regional scales, which are crucial for realistic surface albedo parameterization to significantly advance sea ice forecast and projection models.

Everyone wins - a program to upgrade energy efficiency in manufactured housing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, A.D.; Onisko, S.A.; Sandahl, L.J.

1994-03-01

Other regions might well benefit from this case history, illustrating how a region marshalled its resources to bring manufactured housing--a significant share of its new residential sector--into the modern era of energy efficiency. Everyone was a winner. In the Pacific Northwest, as in many parts of the country, a significant proportion of new homes are HUD-code manufactured, or so-called mobile, homes. About 25% of new single-family houses in the Pacific Northwest are manufactured homes. They represent an even larger share - nearly 40% - of new electrically heated housing in the region, and this share has been growing. When Congressmore » enacted the Pacific Northwest Power Planning Act of 1980, it also permitted the four Northwest states to establish an interstate compact body - the Northwest Power Planning Council - and required the Council to produce an integrated resource plan for the region served by the Bonneville Power Administration, the federal power marketing and transmission agency that operates the region's major transmission grid and sells most of its bulk power. Both the law and the plan charge Bonneville with developing cost-effective programs to save electricity in all end-use sectors through improved energy efficiency.« less

Space use of a dominant Arctic vertebrate: Effects of prey, sea ice, and land on Pacific walrus resource selection

USGS Publications Warehouse

Beatty, William; Jay, Chadwick V.; Fischbach, Anthony S.; Grebmeier, Jacqueline M.; Taylor, Rebecca L.; Blanchard, Arny L.; Jewett, Stephen C.

2016-01-01

Sea ice dominates marine ecosystems in the Arctic, and recent reductions in sea ice may alter food webs throughout the region. Sea ice loss may also stress Pacific walruses (Odobenus rosmarus divergens), which feed on benthic macroinvertebrates in the Bering and Chukchi seas. However, no studies have examined the effects of sea ice on foraging Pacific walrus space use patterns. We tested a series of hypotheses that examined walrus foraging resource selection as a function of proximity to resting substrates and prey biomass. We quantified walrus prey biomass with 17 benthic invertebrate families, which included bivalves, polychaetes, amphipods, tunicates, and sipunculids. We included covariates for distance to sea ice and distance to land, and systematically developed a series of candidate models to examine interactions among benthic prey biomass and resting substrates. We ranked candidate models with Bayesian Information Criterion and made inferences on walrus resource selection based on the top-ranked model. Based on the top model, biomass of the bivalve family Tellinidae, distance to ice, distance to land, and the interaction of distances to ice and land all positively influenced walrus foraging resource selection. Standardized model coefficients indicated that distance to ice explained the most variation in walrus foraging resource selection followed by Tellinidae biomass. Distance to land and the interaction of distances to ice and land accounted for similar levels of variation. Tellinidae biomass likely represented an index of overall bivalve biomass, indicating walruses focused foraging in areas with elevated levels of bivalve and tellinid biomass. Our results also emphasize the importance of sea ice to walruses. Projected sea ice loss will increase the duration of the open water season in the Chukchi Sea, altering the spatial distribution of resting sites relative to current foraging areas and possibly affecting the spatial structure of benthic communities.

Deep-water chemosynthetic ecosystem research during the census of marine life decade and beyond: a proposed deep-ocean road map.

PubMed

German, Christopher R; Ramirez-Llodra, Eva; Baker, Maria C; Tyler, Paul A

2011-01-01

The ChEss project of the Census of Marine Life (2002-2010) helped foster internationally-coordinated studies worldwide focusing on exploration for, and characterization of new deep-sea chemosynthetic ecosystem sites. This work has advanced our understanding of the nature and factors controlling the biogeography and biodiversity of these ecosystems in four geographic locations: the Atlantic Equatorial Belt (AEB), the New Zealand region, the Arctic and Antarctic and the SE Pacific off Chile. In the AEB, major discoveries include hydrothermal seeps on the Costa Rica margin, deepest vents found on the Mid-Cayman Rise and the hottest vents found on the Southern Mid-Atlantic Ridge. It was also shown that the major fracture zones on the MAR do not create barriers for the dispersal but may act as trans-Atlantic conduits for larvae. In New Zealand, investigations of a newly found large cold-seep area suggest that this region may be a new biogeographic province. In the Arctic, the newly discovered sites on the Mohns Ridge (71 °N) showed extensive mats of sulfur-oxidisng bacteria, but only one gastropod potentially bears chemosynthetic symbionts, while cold seeps on the Haakon Mossby Mud Volcano (72 °N) are dominated by siboglinid worms. In the Antarctic region, the first hydrothermal vents south of the Polar Front were located and biological results indicate that they may represent a new biogeographic province. The recent exploration of the South Pacific region has provided evidence for a sediment hosted hydrothermal source near a methane-rich cold-seep area. Based on our 8 years of investigations of deep-water chemosynthetic ecosystems worldwide, we suggest highest priorities for future research: (i) continued exploration of the deep-ocean ridge-crest; (ii) increased focus on anthropogenic impacts; (iii) concerted effort to coordinate a major investigation of the deep South Pacific Ocean - the largest contiguous habitat for life within Earth's biosphere, but also the world's least investigated deep-ocean basin.

Ecosystem characteristics and processes facilitating persistent macrobenthic biomass hotspots and associated benthivory in the Pacific Arctic

NASA Astrophysics Data System (ADS)

Grebmeier, Jacqueline M.; Bluhm, Bodil A.; Cooper, Lee W.; Danielson, Seth L.; Arrigo, Kevin R.; Blanchard, Arny L.; Clarke, Janet T.; Day, Robert H.; Frey, Karen E.; Gradinger, Rolf R.; Kędra, Monika; Konar, Brenda; Kuletz, Kathy J.; Lee, Sang H.; Lovvorn, James R.; Norcross, Brenda L.; Okkonen, Stephen R.

2015-08-01

The northern Bering and Chukchi Seas are areas in the Pacific Arctic characterized by high northward advection of Pacific Ocean water, with seasonal variability in sea ice cover, water mass characteristics, and benthic processes. In this review, we evaluate the biological and environmental factors that support communities of benthic prey on the continental shelves, with a focus on four macrofaunal biomass "hotspots." For the purpose of this study, we define hotspots as macrofaunal benthic communities with high biomass that support a corresponding ecological guild of benthivorous seabird and marine mammal populations. These four benthic hotspots are regions within the influence of the St. Lawrence Island Polynya (SLIP), the Chirikov Basin between St. Lawrence Island and Bering Strait (Chirikov), north of Bering Strait in the southeast Chukchi Sea (SECS), and in the northeast Chukchi Sea (NECS). Detailed benthic macrofaunal sampling indicates that these hotspot regions have been persistent over four decades of sampling due to annual reoccurrence of seasonally consistent, moderate-to-high water column production with significant export of carbon to the underlying sediments. We also evaluate the usage of the four benthic hotspot regions by benthic prey consumers to illuminate predator-prey connectivity. In the SLIP hotspot, spectacled eiders and walruses are important winter consumers of infaunal bivalves and polychaetes, along with epibenthic gastropods and crabs. In the Chirikov hotspot, gray whales have historically been the largest summer consumers of benthic macrofauna, primarily feeding on ampeliscid amphipods in the summer, but they are also foraging further northward in the SECS and NECS hotspots. Areas of concentrated walrus foraging occur in the SLIP hotspot in winter and early spring, the NECS hotspot in summer, and the SECS hotspot in fall. Bottom up forcing by hydrography and food supply to the benthos influences persistence and composition of benthic prey that then influences the distributions of benthivorous upper trophic level populations.

Combined effect of the East Atlantic/West Russia and Western Pacific teleconnections on the East Asian winter monsoon

NASA Astrophysics Data System (ADS)

Oh, Hyoeun; Jhun, Jong-Ghap; Ha, Kyung-Ja; Seo, Kyong-Hwan

2017-05-01

This study investigates the individual effects of the East Atlantic/West Russia (EATL/WRUS) and Western Pacific (WP) teleconnection patterns and their combined effect on the East Asian winter monsoon (EAWM). The contributions of the respective EATL/WRUS and WP teleconnection patterns to the EAWM are revealed by removing the dependence on the Arctic Oscillation (AO) and the El Niño-Southern Oscillation (ENSO) using a linear regression, which are named as N_EATL/WRUS and N_WP, respectively. This is because the EATL/WRUS (WP) is closely linked to the Arctic (tropics) region. A significant increase (decrease) in temperature over East Asia (EA) corresponding to a weak (strong) EAWM is associated with the N_EATL/WRUS and N_WP teleconnection patterns during the positive (negative) phases. In order to examine impacts of these two teleconnections on the EAWM, three types of effects are reconstructed on the basis of ± 0.5 standard deviation: 1) Combined effect, 2) N_EATL/WRUS effect, and 3) N_WP effect. The positive N_EATL/WRUS teleconnection induces to a weakened Siberian High and a shallow EA trough at the mid-troposphere through wave propagation, leading to the weak EAWM. During the positive N_WP pattern, warm air from the tropics flows toward the EA along western flank of an anomalous anticyclone over the North Pacific that is relevant to the meridional shift of the Aleutian Low. When the two mid-latitude teleconnections have the in-phase combination, the increase in temperature over EA appears to be more pronounced than the individual effects by transporting warm air from tropics via strong southeasterly wind anomalies induced by anomalous zonal pressure gradient between the Siberian High and Aleutian Low. Therefore, the impact of the mid-latitude teleconnections on the EAWM becomes robust and linearly superimposed, unlike a nonlinear in-phase combined effect of the AO and ENSO.

Deep-Water Chemosynthetic Ecosystem Research during the Census of Marine Life Decade and Beyond: A Proposed Deep-Ocean Road Map

PubMed Central

German, Christopher R.; Ramirez-Llodra, Eva; Baker, Maria C.; Tyler, Paul A.

2011-01-01

The ChEss project of the Census of Marine Life (2002–2010) helped foster internationally-coordinated studies worldwide focusing on exploration for, and characterization of new deep-sea chemosynthetic ecosystem sites. This work has advanced our understanding of the nature and factors controlling the biogeography and biodiversity of these ecosystems in four geographic locations: the Atlantic Equatorial Belt (AEB), the New Zealand region, the Arctic and Antarctic and the SE Pacific off Chile. In the AEB, major discoveries include hydrothermal seeps on the Costa Rica margin, deepest vents found on the Mid-Cayman Rise and the hottest vents found on the Southern Mid-Atlantic Ridge. It was also shown that the major fracture zones on the MAR do not create barriers for the dispersal but may act as trans-Atlantic conduits for larvae. In New Zealand, investigations of a newly found large cold-seep area suggest that this region may be a new biogeographic province. In the Arctic, the newly discovered sites on the Mohns Ridge (71°N) showed extensive mats of sulfur-oxidisng bacteria, but only one gastropod potentially bears chemosynthetic symbionts, while cold seeps on the Haakon Mossby Mud Volcano (72°N) are dominated by siboglinid worms. In the Antarctic region, the first hydrothermal vents south of the Polar Front were located and biological results indicate that they may represent a new biogeographic province. The recent exploration of the South Pacific region has provided evidence for a sediment hosted hydrothermal source near a methane-rich cold-seep area. Based on our 8 years of investigations of deep-water chemosynthetic ecosystems worldwide, we suggest highest priorities for future research: (i) continued exploration of the deep-ocean ridge-crest; (ii) increased focus on anthropogenic impacts; (iii) concerted effort to coordinate a major investigation of the deep South Pacific Ocean – the largest contiguous habitat for life within Earth's biosphere, but also the world's least investigated deep-ocean basin. PMID:21829722

A meteorological interpretation of the Arctic Boundary Layer Expedition (ABLE) 3B flight series

NASA Technical Reports Server (NTRS)

Shipham, Mark C.; Bachmeier, A. Scott; Cahoon, Donald R., Jr.; Gregory, Gerald L.; Anderson, Bruce E.; Browell, Edward V.

1994-01-01

The Arctic Boundary Layer Expedition (ABLE) 3B was conducted to determine the summertime tropospheric distribution, sources, and sinks of important trace gas and aerosol species over the wetlands and boreal forests of central and eastern Canada. Isentropic trajectories and analyzed midtropospheric circulation patterns were used to group flights according to the transport histories of polar, midlatitude, or tropical air masses which were sampled. These data were then divided into bands of potential temperature levels representing the low, middle, and maximum aircraft altitudes to assess the effects of both local and long distance transport and natural and man-made pollutants to the measured chemical species. Detailed case studies are provided to depict the complex three-dimensional airflow regimes that transported air with differing chemical signatures to the study area. Mission 6 details the large-scale movement of smoke in the generally prevailing west to northwesterly airflow that was observed on the majority of flights. Mission 1 analyzes the horizontal and vertical motions of maritime Pacific air in the upper troposphere that was routinely mixed downward to the aircraft altitude. Finally, mission 14 tracks the far northward excursion of tropical air that had been associated with a Pacific typhoon. The following three factors all had important influences on the collected chemical data sets: (1) local and distant stratospheric in puts into the upper and middle troposphere; (2) biomass-burning plumes from active fires in Alaska and Canada; (3) a band of 'low ozone' upper tropospheric air that was observed by airborne differential absorption lidar (DIAL) above the aircraft maximum altitude. Other modification factors observed on some flights included urban pollution from U.S. and Canadian cities, tropical air that had been associated with a Pacific typhoon, and precipitation scavenging by clouds and rain. Many flights were affected by several of the above factors which led to complex chemical signatures that will be discussed in other companion papers.

Possible connections of the opposite trends in Arctic and Antarctic sea-ice cover.

PubMed

Yu, Lejiang; Zhong, Shiyuan; Winkler, Julie A; Zhou, Mingyu; Lenschow, Donald H; Li, Bingrui; Wang, Xianqiao; Yang, Qinghua

2017-04-05

Sea ice is an important component of the global climate system and a key indicator of climate change. A decreasing trend in Arctic sea-ice concentration is evident in recent years, whereas Antarctic sea-ice concentration exhibits a generally increasing trend. Various studies have investigated the underlying causes of the observed trends for each region, but possible linkages between the regional trends have not been studied. Here, we hypothesize that the opposite trends in Arctic and Antarctic sea-ice concentration may be linked, at least partially, through interdecadal variability of the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). Although evaluation of this hypothesis is constrained by the limitations of the sea-ice cover record, preliminary statistical analyses of one short-term and two long-term time series of observed and reanalysis sea-ice concentrations data suggest the possibility of the hypothesized linkages. For all three data sets, the leading mode of variability of global sea-ice concentration is positively correlated with the AMO and negatively correlated with the PDO. Two wave trains related to the PDO and the AMO appear to produce anomalous surface-air temperature and low-level wind fields in the two polar regions that contribute to the opposite changes in sea-ice concentration.

Possible connections of the opposite trends in Arctic and Antarctic sea-ice cover

PubMed Central

Yu, Lejiang; Zhong, Shiyuan; Winkler, Julie A.; Zhou, Mingyu; Lenschow, Donald H.; Li, Bingrui; Wang, Xianqiao; Yang, Qinghua

2017-01-01

Sea ice is an important component of the global climate system and a key indicator of climate change. A decreasing trend in Arctic sea-ice concentration is evident in recent years, whereas Antarctic sea-ice concentration exhibits a generally increasing trend. Various studies have investigated the underlying causes of the observed trends for each region, but possible linkages between the regional trends have not been studied. Here, we hypothesize that the opposite trends in Arctic and Antarctic sea-ice concentration may be linked, at least partially, through interdecadal variability of the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). Although evaluation of this hypothesis is constrained by the limitations of the sea-ice cover record, preliminary statistical analyses of one short-term and two long-term time series of observed and reanalysis sea-ice concentrations data suggest the possibility of the hypothesized linkages. For all three data sets, the leading mode of variability of global sea-ice concentration is positively correlated with the AMO and negatively correlated with the PDO. Two wave trains related to the PDO and the AMO appear to produce anomalous surface-air temperature and low-level wind fields in the two polar regions that contribute to the opposite changes in sea-ice concentration. PMID:28378830

Genetic profiling links changing sea-ice to shifting beluga whale migration patterns

PubMed Central

Mahoney, Andrew R.; Suydam, Robert; Quakenbush, Lori; Whiting, Alex; Lowry, Lloyd; Harwood, Lois

2016-01-01

There is increasing concern over how Arctic fauna will adapt to climate related changes in sea-ice. We used long-term sighting and genetic data on beluga whales (Delphinapterus leucas) in conjunction with multi-decadal patterns of sea-ice in the Pacific Arctic to investigate the influence of sea-ice on spring migration and summer residency patterns. Substantial variations in sea-ice conditions were detected across seasons, years and sub-regions, revealing ice–ocean dynamics more complex than Arctic-wide trends suggest. This variation contrasted with a highly consistent pattern of migration and residency by several populations, indicating that belugas can accommodate widely varying sea-ice conditions to perpetuate philopatry to coastal migration destinations. However, a number of anomalous migration and residency events were detected and coincided with anomalous ice years, and in one case with an increase in killer whale (Orcinus orca) sightings and reported predation on beluga whales. The behavioural shifts were likely driven by changing sea-ice and associated changes in resource dispersion and predation risk. Continued reductions in sea-ice may result in increased predation at key aggregation areas and shifts in beluga whale behaviour with implications for population viability, ecosystem structure and the subsistence cultures that rely on them.

Impact of the Pacific Decadal Oscillation on summertime surface temperatures of inland water bodies in Alaska (USA) and northwest Canada

NASA Astrophysics Data System (ADS)

Healey, N.; Hook, S. J.

2016-12-01

Due to water's high heat capacity, temperature fluctuations in lacustrine systems are a reflection of long-term ambient climate conditions rather than short-term meteorological forcing. There are many atmospheric phenomena (i.e. teleconnections) that influence the regional climatology of the Pacific basin, and one of the most influential is the Pacific Decadal Oscillation (PDO). This study examines spaceborne observations by the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Visible Infrared Imaging Radiometer Suite (VIIRS) from 2000-2015 of 15 inland water bodies in Alaska and Canada using the Inland Waterbody Surface Temperature (IWbST) version 1.0 algorithm. We analyze surface temperature trends in comparison to the variation of the PDO, and our findings suggest that the PDO is influencing summertime (July-September) inland water bodies in southern Alaska and northwestern Canada. The strongest influence is prevalent in the water bodies experiencing a maritime climate and situated closest to the Aleutian Peninsula/Gulf of Alaska. The second largest influence occurs in the northwestern Canadian water bodies that experience a weakened maritime climate, or a transitional regime between maritime and continental classifications. The weakest relationship with the PDO are water bodies located in the western, northwestern, and interior Alaska regions that experience more of a continental climate regime which are likely controlled by other large-scale teleconnections such as the Arctic Oscillation, the Pacific North American Index, or the North Pacific Index.

Population genetics studies of the walrus (Odobenus rosmarus): A summary and interpretation of results and research needs

USGS Publications Warehouse

Scribner, Kim T.; Hills, Susan; Fain, Steven R.; Cronin, Matthew A.; Dizon, Andrew E.; Chivers, Susan J.; Perrin, William F.

1997-01-01

A summary of population genetics data is presented for the walrus (Odobenus rosmarus). Current information on the ecology and behavior of the species is highlighted to aid in the interpretation of genetics results and to suggest future areas of research. Walruses are discontinuously distributed across the Arctic and are currently subdivided into six regional populations on the basis of historical distribution and morphology. Few population genetics studies have been conducted on the walrus. Only three of the six trigonal populations have been surveyed with biochemical or molecular techniques. Analysis of mitochondrial DNA (mtDNA) variation among walruses from the northern Pacific (Chukchi Sea) and western Atlantic (Greenland) regions revealed 13 haplotypes; 6 were found only in Pacific walruses while 7 were unique to the Atlantic subspecies. Estimates of sequence divergence between Atlantic and Pacific haplotypes were 1.0%-1.6%. No evidence of microgeographic structuring within the northern Pacific or western Atlantic regional populations was found on the basis of mtDNA haplotype frequency distributions or multilocus minisatellite band sharing. Minisatellite analysis of adult-juvenile and adult-adult pairs suggests that assemblages of walruses on individual ice floes are made up at least in part by groups of related individuals from more than one generation. Furthermore, high mtDNA haplotype diversities and low minisatellite band-sharing values suggest that both the northern Pacific and western Atlantic walruses have retained a high degree of genetic variability.

The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC)

NASA Astrophysics Data System (ADS)

Rex, M.; Shupe, M.; Dethloff, K.

2017-12-01

MOSAiC is an international initiative under the umbrella of the International Arctic Science Committee (IASC) designed by an international consortium of leading polar research institutes. Rapid changes in the Arctic lead to an urgent need for reliable information about the state and evolution of the Arctic climate system. This requires more observations and improved modelling over various spatial and temporal scales, and across a wide variety of disciplines. Observations of many critical parameters were never made in the central Arctic for a full annual cycle. MOSAiC will be the first year-around expedition into the central Arctic exploring the coupled climate system. The research vessel Polarstern will drift with the sea ice across the central Arctic during the years 2019 to 2020. The drift starts in the Siberian sector of the Arctic in late summer. A distributed regional network of observational sites will be established on the sea ice in an area of up to 50 km distance from Polarstern, representing a grid cell of climate models. The ship and the surrounding network will drift with the natural sea ice drift across the polar cap towards the Atlantic. The focus of MOSAiC lies on in-situ observations of the climate processes that couple atmosphere, ocean, sea ice, biogeochemistry and ecosystem. These measurements will be supported by weather and sea ice predictions and remote sensing operations to make the expedition successful. The expedition includes aircraft operations and cruises by icebreakers from MOSAiC partners. All these observations will be used for the main scientific goals of MOSAiC, enhancing the understanding of the regional and global consequences of Arctic climate change and sea ice loss and improve weather and climate prediction. More precisely, the results are needed to advance the data assimilation for numerical weather prediction models, sea ice forecasts and climate models and ground truth for satellite remote sensing. Additionally, the understanding of energy budget and fluxes through interfaces, sources, sinks and cycles of chemical species, boundary layer processes, and primary productivity will be investigated during the expedition. MOSAiC will support safer maritime and offshore operations, contribute to an improved scientific future fishery and traffic along the northern sea routes.

Honduras Defense Policy.

DTIC Science & Technology

1986-04-22

political, military, economic and social sectors. DO I JAN73 1473 EDITION OF I NOV GS IS OBSOLETE SECURITY CLASSIFICATION OF THIS PAGE (Wlen Data Entered...political military, economic and social sectors. NTIS CRA&I D -1 srl ooocB d Ju t l, atuo .. . By VI. lbut,.or / Availdbility Codes Dibt ,-.•or 0LIJ A...Pacific Ocean in the north and south, Honduras is the link that divides the Central American Isthmus in half. Any political, social or military event

From upstream to downstream: Megatrends and latest developments in Latin America`s hydrocarbons sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Kang; Pezeshki, S.; McMahon, J.

1995-08-01

In recent years, Latin America`s hydrocarbons sector has been characterized by reorganization, revitalization, regional cooperation, environmental awakening, and steady expansion. The pattern of these changes, which appear to be the megatrends of the region`s hydrocarbons sector development, will continue during the rest of the 1990s. To further study the current situation and future prospects of Latin America`s hydrocarbons sector, we critically summarize in this short article the key issues in the region`s oil and gas development. These megatrends in Latin America`s hydrocarbons sector development will impact not only the future energy demand and supply in the region, but also globalmore » oil flows in the North American market and across the Pacific Ocean. Each country is individually discussed; pipelines to be constructed are discussed also.« less

Experimental and natural host specificity of Loma salmonae (Microsporidia).

PubMed

Shaw, R W; Kent, M L; Brown, A M; Whipps, C M; Adamson, M L

2000-03-14

The microsporidian Loma salmonae (Putz, Hoffman & Dunbar, 1965) Morrison & Sprague, 1981 has caused significant gill disease in Pacific salmon Oncorhynchus spp. Host specificity of the parasite was examined experimentally by per os challenge of selected salmonids and non-salmonids with infective chinook salmon O. tshawytscha gill material. Pink Oncorhynchus gorbuscha and chum salmon O. keta, brown Salmo trutta and brook trout Salvelinus fontinalis, and chinook salmon (controls) were positive, whereas Atlantic salmon Salmo salar and Arctic char Salvelinus alpinus were negative. In addition, no non-salmonids were susceptible to experimental exposure. Wild Pacific salmon species in British Columbia, Canada, were examined for L. salmonae during their freshwater life history stages (smolts, prespawning, spawning). All stages were infected, although infections in smolts were only detectable using a L. salmonae-specific PCR test. Many previous Loma spp. described from Oncorhychus spp. are likely L. salmonae based on host, parasite morphology, and site of infection.

Sea ice dynamics across the Mid-Pleistocene transition in the Bering Sea.

PubMed

Detlef, H; Belt, S T; Sosdian, S M; Smik, L; Lear, C H; Hall, I R; Cabedo-Sanz, P; Husum, K; Kender, S

2018-03-05

Sea ice and associated feedback mechanisms play an important role for both long- and short-term climate change. Our ability to predict future sea ice extent, however, hinges on a greater understanding of past sea ice dynamics. Here we investigate sea ice changes in the eastern Bering Sea prior to, across, and after the Mid-Pleistocene transition (MPT). The sea ice record, based on the Arctic sea ice biomarker IP 25 and related open water proxies from the International Ocean Discovery Program Site U1343, shows a substantial increase in sea ice extent across the MPT. The occurrence of late-glacial/deglacial sea ice maxima are consistent with sea ice/land ice hysteresis and land-glacier retreat via the temperature-precipitation feedback. We also identify interactions of sea ice with phytoplankton growth and ocean circulation patterns, which have important implications for glacial North Pacific Intermediate Water formation and potentially North Pacific abyssal carbon storage.

Blood selenium concentrations in female Pacific black brant molting in Arctic Alaska: Relationships with age and habitat salinity

USGS Publications Warehouse

Franson, J. Christian; Flint, Paul L.; Schmutz, Joel A.

2016-01-01

Blood samples collected from 81 female Pacific black brant (Branta bernicla nigricans) molting near Teshekpuk Lake, Alaska, were analyzed for selenium concentration. The concentration of selenium in blood of after second year (hatched two or more years ago) females (0.84 μg/g wet weight) was significantly greater than the concentration in second year (hatched the previous year) females (0.61 μg/g wet weight). The concentrations of selenium we found in blood of black brant were 1.5 to 2 times greater than baseline values typical of freshwater birds, but considerably lower than reported in other marine waterfowl sampled in Alaska. This finding may be attributable in part to the nearly exclusive herbivorous diet of black brant. No relationship was noted between blood selenium concentration and molting habitat salinity. We are unaware of any previous reports of blood selenium concentrations in black brant.

Modulation of the relationship between spring AO and the subsequent winter ENSO by the preceding November AO.

PubMed

Chen, Shangfeng; Chen, Wen; Yu, Bin

2018-05-02

Previous studies indicated that the spring Arctic Oscillation (AO) exerts significant influences on the subsequent winter El Niño-Southern Oscillation (ENSO). This analysis suggests that the spring AO-ENSO linkage is highly modulated by its preceding November AO. When November and the subsequent spring AO indices are in phase, the spring AO has a pronounced influence on ENSO. However, when the November and spring AO indices are out of phase, the spring AO-ENSO connection disappears. Modulation of the November AO on the spring AO-ENSO connection is mainly through the constructive and destructive superposition of the November and spring AO associated sea surface temperature (SST) anomalies in the tropical central-eastern Pacific in spring and summer, as well as the SST anomalies developed further in the tropical Pacific via the positive air-sea feedback.

GCM simulations of intraseasonal variability in the Pacific/North American region

NASA Technical Reports Server (NTRS)

Schubert, Siegfried; Suarez, Max; Park, Chung-Kyu; Moorthi, Shrinivas

1993-01-01

General circulation model (GCM) simulations of low-frequency variability with time scales of 20 to 70 days are analyzed for the Pacific sector during boreal winter. The GCM's leading mode in the upper-tropospheric zonal wind is associated with fluctuations of the East Asian jet; this mode resembles, in both structure and amplitude, the Pacific/North American (PNA) pattern found in the observations on these time scales. In both the model and observations, the PNA anomaly is characterized by: (1) a linear balance in the upper-tropospheric vorticity budget with no significant Rossby wave source in the tropics, (2) a barotropic conversion of kinetic energy from the time mean Pacific jet, and (3) a north/south displacement of the Pacific storm track. In the GCM, the latter is associated with synoptic eddy heat flux and latent heat anomalies that appear to contribute to a strong lower-tropospheric source of wave activity over the North Pacific. This is in contrast to the observations, which show only a weak source of wave activity in this region.

Forced Climate Changes in West Antarctica and the Indo-Pacific by Northern Hemisphere Ice Sheet Topography

NASA Astrophysics Data System (ADS)

Jones, T. R.; Roberts, W. H. G.; Steig, E. J.; Cuffey, K. M.; Markle, B. R.; White, J. W. C.

2017-12-01

The behavior of the Indo-Pacific climate system across the last deglaciation is widely debated. Resolving these debates requires long term and continuous climate proxy records. Here, we use an ultra-high resolution and continuous water isotope record from an ice core in the Pacific sector of West Antarctica. In conjunction with the HadCM3 coupled ocean-atmosphere GCM, we demonstrate that the climate of both West Antarctica and the Indo-Pacific were substantially altered during the last deglaciation by the same forcing mechanism. Critically, these changes are not dependent on ENSO strength, but rather the location of deep tropical convection, which shifts at 16 ka in response to climate perturbations induced by the Laurentide Ice Sheet. The changed rainfall patterns in the tropics explain the deglacial shift from expanded-grasslands to rainforest-dominated ecosystems in Indonesia. High-frequency climate variability in the Southern Hemisphere is also changed, through a tropical Pacific teleconnection link dependent on the propogration of Rossby Waves.

Satellite observed salinity distributions at high latitudes in the Northern Hemisphere: A comparison of four products

NASA Astrophysics Data System (ADS)

Garcia-Eidell, Cynthia; Comiso, Josefino C.; Dinnat, Emmanuel; Brucker, Ludovic

2017-09-01

Global surface ocean salinity measurements have been available since the launch of SMOS in 2009 and coverage was further enhanced with the launch of Aquarius in 2011. In the polar regions where spatial and temporal changes in sea surface salinity (SSS) are deemed important, the data have not been as robustly validated because of the paucity of in situ measurements. This study presents a comparison of four SSS products in the ice-free Arctic region, three using Aquarius data and one using SMOS data. The accuracy of each product is assessed through comparative analysis with ship and other in situ measurements. Results indicate RMS errors ranging between 0.33 and 0.89 psu. Overall, the four products show generally good consistency in spatial distribution with the Atlantic side being more saline than the Pacific side. A good agreement between the ship and satellite measurements was also observed in the low salinity regions in the Arctic Ocean, where SSS in situ measurements are usually sparse, at the end of summer melt seasons. Some discrepancies including biases of about 1 psu between the products in spatial and temporal distribution are observed. These are due in part to differences in retrieval techniques, geophysical filtering, and sea ice and land masks. The monthly SSS retrievals in the Arctic from 2011 to 2015 showed variations (within ˜1 psu) consistent with effects of sea ice seasonal cycles. This study indicates that spaceborne observations capture the seasonality and interannual variability of SSS in the Arctic with reasonably good accuracy.

High Northern Latitude Insolation Forcing of Tropical Monsoons or Monsoon Forcing of High Northern Latitude Ice Volume?

NASA Astrophysics Data System (ADS)

Beck, W.; Zhou, W.; Cheng, L.; Wu, Z.; Xian, F.; Kong, X.; Cottam, T.; An, Z.; White, L.

2017-12-01

We show that atmospheric 10Be flux is a quantitative proxy for rainfall, and use it to derive a 530Ka-long record of East Asian summer monsoon rainfall from Chinese Loess. Our record strongly resembles the Red Sea paleosea level and LR04 benthic foram δ18O records, with 53% & 45% of its variance reflected in each of these two global ice volume proxies. This suggests EASM intensity is closely coupled to ice volume by some mechanism. At first glance, this seems to support the claim based on strongly correlated Chinese cave δ18O and 65°N summer solar insolation that Asian monsoon intensity is controlled by high northern latitude insolation. Nevertheless, our 10Be-proxy has only 17% common variance with cave δ18O. Furthermore, Chinese cave δ18O records are very poorly correlated with sea-level/global ice volume, conflicting with both our proxy and Milankovitch theory, if interpreted as a monsoon intensity proxy. We argue that cave δ18O is instead a mixing proxy for monsoon moisture derived from (δ18O depleted) Indian vs Pacific monsoon sectors. We suggest both this mixing ratio and EASM intensity are not governed by high northern latitude insolation, but rather by orbital forcing of the low latitude interhemispheric insolation gradient, which mimics the 65°N insolation pattern. We show this gradient regulates the ratio of Asian monsoon outflow to the Indian vs. North Pacific subtropical highs, providing a coupling to both Hadley and Walker circulations. When outflow strengthens in one of these sectors it weakens in the other, regulating the relative strength of the Trade and Westerly winds in each sector. Trade wind coupling to monsoon strength in each sector controls the ISM/Pacific monsoon moisture mixing ratio and EASM intensity, although intensity is also influenced by other factors. This model provides mechanisms by which the monsoons may influence ice volume. Westerlies strength adjacent to the North Pacific Subtropical High strongly regulates transient eddy energy transport to the north polar region. Likewise, the Trades and Westerlies in the Indian Ocean both influence AMOC strength by regulating Agulhas leakage into the Atlantic, or can influence air/sea CO2 fluxes. These mechanisms may all strongly influence northern hemisphere ice volume, begging the question: Where does global climate control originate?

Structural-tectonic zoning of the Arctic

NASA Astrophysics Data System (ADS)

Petrov, Oleg; Sobolev, Nikolay; Morozov, Andrey; Shokalsky, Sergey; Kashubin, Sergey; Grikurov, Garrik; Tolmacheva, Tatiana; Rekant, Pavel; Petrov, Evgeny

2017-04-01

Structural-tectonic zoning of the Arctic is based on the processing of geological and geophysical data and bottom sampling materials produced within the project "Atlas of Geological Maps of the Circumpolar Arctic." Zoning of the Arctic territories has been conducted taking into account the Earth's crust types, age of consolidated basement, and features of geological structure of the sedimentary cover. Developed legend for the zoning scheme incorporates five main groups of elements: continental and oceanic crust, folded platform covers, accretion-collision systems, and provinces of continental cover basalts. An important feature of the structural-tectonic zoning scheme is designation of continental crust in the central regions of the Arctic Ocean, the existence of which is assumed on the basis of numerous geological data. It has been found that most of the Arctic region has continental crust with the exception of the Eurasian Basin and the central part of the Canada Basin, which are characterized by oceanic crust type. Thickness of continental crust from seismic data varies widely: from 30-32 km on the Mendeleev Rise to 18-20 km on the Lomonosov Ridge, decreasing to 8-10 km in rift structures of the Podvodnikov-Makarov Basin at the expense of reduction of the upper granite layer. New data confirm similar basement structure on the western and eastern continental margins of the Eurasian oceanic basin. South to north, areas of Neoproterozoic (Baikalian) and Paleozoic (Ellesmerian) folding are successively distinguished. Neoproterozoic foldbelt is observed in Central Taimyr (Byrranga Mountains). Continuation of this belt in the eastern part of the Arctic is Novosibirsk-Chukchi fold system. Ellesmerian orogen incorporates the northernmost areas of Taimyr and Severnaya Zemlya, wherefrom it can be traced to the Geofizikov Spur of the Lomonosov Ridge and further across the De Long Archipelago and North Chukchi Basin to the north of Alaska Peninsula and in the Beaufort Sea. From the north, Ellesmerides are limited by the Precambrian continental blocks - North Kara and Mendeleev Rise, the sedimentary cover within which is represented by undisturbed Paleozoic and Mesozoic deposits. Analysis of the geological and tectonic maps and the map of the Arctic basement structure indicates that the heterogeneous crustal structure of the Arctic Ocean and its continental framing were formed as a result of simultaneous development and interaction of three large paleo-oceans in the Neoproterozoic and Phanerozoic - Paleo-Asian, Proto-Atlantic and Paleo-Pacific oceans. A conceptual model that represents our understanding of structural relationships and crustal types of the main Arctic Basin structures is quite simple. The Arctic Basin is bounded by continental margins with continental crust: relatively elevated Barents-Kara - in the west, and generally submerged Amerasia margin - in the east. The latter represents a continental "bridge" formed by thinned and stretched continental crust. It connects two opposite continents - Laurentia and Eurasia, and is essentially a fragmented, tectonically mobile structure.

Worldwide Emerging Environmental Issues Affecting the U.S. Military. January 2006 Report

DTIC Science & Technology

2006-01-01

8 10.3.2 Global Warming Threshold Might Have Been Crossed…………………………..8 10.3.3 Several Small Asia/Pacific Countries at Risk because of Rising Sea... Global Warming Threshold Might Have Been Crossed In the preamble to his upcoming book, ’The Revenge of Gaia’, James Lovelock, who formulated the Gaia...intense actions are needed to curb global warming . Scientists studying the Arctic are also noting that the polar region is close to or on the edge of the

ICESCAPE Mission

NASA Image and Video Library

2010-07-08

Clark University's Luke Trusel works amid sea ice in the Chukchi Sea on July 9, 2010, and logs the depths at which measurements are collected below the ice. The research is part of NASA's ICESCAPE mission to sample the physical, chemical and biological characteristics of the ocean and sea ice. Impacts of Climate change on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) is a multi-year NASA shipborne project. The bulk of the research will take place in the Beaufort and Chukchi Sea’s in summer of 2010 and fall of 2011. Photo Credit: (NASA/Kathryn Hansen)

Arctic Landscape Within Reach

NASA Technical Reports Server (NTRS)

2008-01-01

This image, one of the first captured by NASA's Phoenix Mars Lander, shows flat ground strewn with tiny pebbles and marked by small-scale polygonal cracking, a pattern seen widely in Martian high latitudes and also observed in permafrost terrains on Earth. The polygonal cracking is believed to have resulted from seasonal contraction and expansion of surface ice.

Phoenix touched down on the Red Planet at 4:53 p.m. Pacific Time (7:53 p.m. Eastern Time), May 25, 2008, in an arctic region called Vastitas Borealis, at 68 degrees north latitude, 234 degrees east longitude.

This image was acquired at the Phoenix landing site by the Surface Stereo Imager on day 1 of the mission on the surface of Mars, or Sol 0, after the May 25, 2008, landing.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Fast Response of the Tropics to an Abrupt Loss of Arctic Sea Ice via Ocean Dynamics

NASA Astrophysics Data System (ADS)

Wang, Kun; Deser, Clara; Sun, Lantao; Tomas, Robert A.

2018-05-01

The role of ocean dynamics in the transient adjustment of the coupled climate system to an abrupt loss of Arctic sea ice is investigated using experiments with Community Climate System Model version 4 in two configurations: a thermodynamic slab mixed layer ocean and a full-depth ocean that includes both dynamics and thermodynamics. Ocean dynamics produce a distinct sea surface temperature warming maximum in the eastern equatorial Pacific, accompanied by an equatorward intensification of the Intertropical Convergence Zone and Hadley Circulation. These tropical responses are established within 25 years of ice loss and contrast markedly with the quasi-steady antisymmetric coupled response in the slab-ocean configuration. A heat budget analysis reveals the importance of anomalous vertical advection tied to a monotonic temperature increase below 200 m for the equatorial sea surface temperature warming maximum in the fully coupled model. Ocean dynamics also rapidly modify the midlatitude atmospheric response to sea ice loss.

U.S. Coast Guard Cutter Healy in the Beaufort Sea

NASA Image and Video Library

2017-12-08

Scientists on board the U.S. Coast Guard Cutter Healy in the Beaufort Sea, northeast of Barrow, Alaska, finished collecting the mission¹s sea ice data and cruised south on July 20, 2011, through thin ice and ultimately into the open ocean. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Discovery of a black smoker vent field and vent fauna at the Arctic Mid-Ocean Ridge

PubMed Central

Pedersen, Rolf B.; Rapp, Hans Tore; Thorseth, Ingunn H.; Lilley, Marvin D.; Barriga, Fernando J. A. S.; Baumberger, Tamara; Flesland, Kristin; Fonseca, Rita; Früh-Green, Gretchen L.; Jorgensen, Steffen L.

2010-01-01

The Arctic Mid-Ocean Ridge (AMOR) represents one of the most slow-spreading ridge systems on Earth. Previous attempts to locate hydrothermal vent fields and unravel the nature of venting, as well as the provenance of vent fauna at this northern and insular termination of the global ridge system, have been unsuccessful. Here, we report the first discovery of a black smoker vent field at the AMOR. The field is located on the crest of an axial volcanic ridge (AVR) and is associated with an unusually large hydrothermal deposit, which documents that extensive venting and long-lived hydrothermal systems exist at ultraslow-spreading ridges, despite their strongly reduced volcanic activity. The vent field hosts a distinct vent fauna that differs from the fauna to the south along the Mid-Atlantic Ridge. The novel vent fauna seems to have developed by local specialization and by migration of fauna from cold seeps and the Pacific. PMID:21119639

Seasonality of Arctic Mediterranean Exchanges

NASA Astrophysics Data System (ADS)

Rieper, Christoph; Quadfasel, Detlef

2015-04-01

The Arctic Mediterranean communicates through a number of passages with the Atlantic and the Pacific Oceans. Most of the volume exchange happens at the Greenland-Scotland-Ridge: warm and saline Atlantic Water flows in at the surface, cold, dense Overflow Water flows back at the bottom and fresh and cold Polar Water flows out along the East Greenland coast. All surface inflows show a seasonal signal whereas only the outflow through the Faroe Bank Channel exhibits significant seasonality. Here we present a quantification of the seasonal cycle of the exchanges across the Greenland-Scotland ridge based on volume estimates of the in- and outflows within the last 20 years (ADCP and altimetry). Our approach is comparatistic: we compare different properties of the seasonal cycle like the strength or the phase between the different in- and outflows. On the seasonal time scale the in- and outflows across the Greenland-Scotland-Ridge are not balanced. The net flux thus has to be balanced by the other passages on the Canadian Archipelago, Bering Strait as well as runoff from land.

Creating a Joint Approach to New Zealand Defence Force Contemporary Amphibious Operations in the South West Pacific

DTIC Science & Technology

2012-03-06

Logistics Support. There were no set agreements in place to use military assets to transport donated goods from NGOs and the private sector . This led to... private sector in the future.25 Lessons Learned: Command and Control. The JTF staff had not been exercised in the lead up to the operation...these islands would have been able to survive on their internal produce and subsistence culture, however in a globalised world, some of them are

Incentives for retaining and motivating health workers in Pacific and Asian countries

PubMed Central

Henderson, Lyn N; Tulloch, Jim

2008-01-01

This paper was initiated by the Australian Agency for International Development (AusAID) after identifying the need for an in-depth synthesis and analysis of available literature and information on incentives for retaining health workers in the Asia-Pacific region. The objectives of this paper are to: 1. Highlight the situation of health workers in Pacific and Asian countries to gain a better understanding of the contributing factors to health worker motivation, dissatisfaction and migration. 2. Examine the regional and global evidence on initiatives to retain a competent and motivated health workforce, especially in rural and remote areas. 3. Suggest ways to address the shortages of health workers in Pacific and Asian countries by using incentives. The review draws on literature and information gathered through a targeted search of websites and databases. Additional reports were gathered through AusAID country offices, UN agencies, and non-government organizations. The severe shortage of health workers in Pacific and Asian countries is a critical issue that must be addressed through policy, planning and implementation of innovative strategies – such as incentives – for retaining and motivating health workers. While economic factors play a significant role in the decisions of workers to remain in the health sector, evidence demonstrates that they are not the only factors. Research findings from the Asia-Pacific region indicate that salaries and benefits, together with working conditions, supervision and management, and education and training opportunities are important. The literature highlights the importance of packaging financial and non-financial incentives. Each country facing shortages of health workers needs to identify the underlying reasons for the shortages, determine what motivates health workers to remain in the health sector, and evaluate the incentives required for maintaining a competent and motivated health workforce. Decision-making factors and responses to financial and non-financial incentives have not been adequately monitored and evaluated in the Asia-Pacific region. Efforts must be made to build the evidence base so that countries can develop appropriate workforce strategies and incentive packages. PMID:18793436

Modelled ocean changes at the Plio-Pleistocene transition driven by Antarctic ice advance

PubMed Central

Hill, Daniel J.; Bolton, Kevin P.; Haywood, Alan M.

2017-01-01

The Earth underwent a major transition from the warm climates of the Pliocene to the Pleistocene ice ages between 3.2 and 2.6 million years ago. The intensification of Northern Hemisphere Glaciation is the most obvious result of the Plio-Pleistocene transition. However, recent data show that the ocean also underwent a significant change, with the convergence of deep water mass properties in the North Pacific and North Atlantic Ocean. Here we show that the lack of coastal ice in the Pacific sector of Antarctica leads to major reductions in Pacific Ocean overturning and the loss of the modern North Pacific Deep Water (NPDW) mass in climate models of the warmest periods of the Pliocene. These results potentially explain the convergence of global deep water mass properties at the Plio-Pleistocene transition, as Circumpolar Deep Water (CDW) became the common source. PMID:28252023

800,000 Years of Arctic Climate Variability: Insights from Lake El'gygytgyn, Far East Russia

NASA Astrophysics Data System (ADS)

Castañeda, I. S.; Habicht, H.; Patterson, M. O.; Burns, S. J.; Deconto, R. M.; Brigham-Grette, J.

2017-12-01

The regional response of the high Arctic to past climate variability is little known prior to 100,000 years ago. In 2009, a 3.6 Ma sediment core was recovered from Lake El'gygytgyn (Russia), the largest and oldest unglaciated Arctic lake basin. These sediments offer a unique opportunity to examine Plio-Pleistocene high-latitude continental climate variability. Determining the magnitude of past Arctic temperature and precipitation variability is especially relevant to understanding the mechanisms and feedbacks contributing to arctic amplification. Here we present results of ongoing organic geochemical analyses of Lake El'gygytgyn sediments focusing on the past 800,000 years. We use the methylation and cyclization index of branched tetraethers (MBT'/CBT) to reconstruct past temperature (Weijers et al., 2007; Peterse et al., 2012; De Jonge et al., 2014) and ratios of plant leaf waxes to examine vegetation variability within the lake catchment. In addition, algal biomarkers and bulk carbon isotopes provide insights into past changes in primary productivity. Trends noted in the MBT'/CBT record are in close agreement with pollen-based temperature estimates throughout the entire core and reveal a strong response to interglacial-glacial variability as well as local summer insolation. Our temperature reconstructions indicate the terrestrial Arctic experienced both warm interglacials and mild glacial periods during the Mid-Pleistocene but transitioned to more extreme temperature fluctuations in the more recent part of the record. Plant leaf wax average chain lengths suggest that glacial intervals were marked by increased aridity, while interglacial periods were wetter at Lake El'gygytgyn. Time-series analysis of the organic geochemical temperature and vegetation reconstructions records revealed variability at precession and obliquity frequencies, respectively. We also find a signal of the Mid-Brunhes Event (MBE) recorded in numerous Lake El'gygytgyn proxy records. Pre- and post-MBE differences are likely attributed to shifts in atmospheric circulation due to the stratification and warming in the North Pacific associated with changes in AABW production, thus providing further support for teleconnections between the high northern and southern latitudes.

Possible signals of poleward surface ocean heat transport, of Arctic basal ice melt, and of the twentieth century solar maximum in the 1904-2012 Isle of Man daily timeseries

NASA Astrophysics Data System (ADS)

Matthews, J. B.; Matthews, J. B. R.

2014-01-01

This is the second of two papers on observational timeseries of top of ocean heat capture. The first reports hourly and daily meridional central tropical Pacific top 3 m timeseries showing high Southern Hemisphere evaporation (2.67 m yr-1) and Northern Hemisphere trapped heat (12 MJ m-2 day-1). We suggested that wind drift/geostrophic stratified gyre circulation transported warm water to the Arctic and led to three phases of Arctic basal ice melt and fluxes of brackish nutrient-rich waters to north Atlantic on centennial timescales. Here we examine daily top metre 1904-2012 timeseries at Isle of Man west coast ~54° N for evidence of tropical and polar surface waters. We compare these to Central England (CET) daily land-air temperatures and to Arctic floating ice heat content and extent. We find three phases of ocean surface heating consistent with basal icemelt buffering greenhouse gas warming until a regime shift post-1986 led to the modern surface temperature rise of ~1 °C in 20 yr. Three phases were: warming +0.018 °C yr-1 from 1904-1939, slight cooling -0.002 °C yr-11940-86 and strong warming +0.037 °C yr-1 1986-2012. For the same periods CET land-air showed: warming +0.015 °C yr-1, slight cooling -0.004 °C yr-1, about half SST warming at +0.018 °C yr-1. The mid-century cooling and a 1959/1963 hot/cold event is consistent with sunspot/solar radiation maximum 1923-2008 leading to record volumes of Arctic ice meltwater and runoff that peaked in 1962/3 British Isles extreme cold winter. The warming Arctic resulted in wind regime and surface water regime shifts post 1986. This coincides with the onset of rapid Arctic annual ice melt. Continued heat imbalance is likely to lead to tidewater glacier basal icemelt and future sealevel rise after remaining relatively stable over 4000 yr. Our work needs confirmation by further fieldwork concentrating on the dynamics and thermodynamics of ocean top 3 m that controls the 93 % anthropogenic global warming in the oceans. This may be done most cost-effectively through focussed multidisciplinary scientific research adaptively managed and funded.

The Intense Arctic Cyclone of Early August 2012: A Dynamically Driven Cyclogenesis Event

NASA Astrophysics Data System (ADS)

Bosart, L. F.; Turchioe, A.; Adamchcik, E.

2013-12-01

A series of surface cyclones formed along an anomalously strong northeast-southwest oriented baroclinic zone over north-central Russia on 1-3 August 2012. These cyclones moved northeastward, intensified slowly, and crossed the coast of Russia by 4 August. The last cyclone in the series strengthened rapidly as it moved poleward over the Arctic Ocean on 5-6 August, achieved a minimum sea level pressure of < 965 hPa by 6 August, and was arguably the most intense storm system to impact the Arctic Ocean in the modern data record going back to the International Geophysical Year in 1957-1958. The purpose of this presentation is to illustrate the structure and life cycle of this Arctic Ocean cyclone from a multiscale perspective. Anticyclonic wave breaking in the upper troposphere across Russia in late July and very early August 2012 created an anomalously strong baroclinic zone across northern Asia between 60-80°N. During 1-5 August, negative 850 hPa temperature anomalies between -2° and -4°C were found poleward of 70-75°N between 90°E and the Dateline over the Arctic Ocean while positive 850 hPa temperature anomalies of 8-9°C were found over eastern Russia near 60°N. The associated anomalously strong 850 hPa meridional temperature gradient of ~10°C (2000 km)-1 helped to sustain an anomalously strong (20-30 m s-1) 250 hPa jet along the coast of northeastern Russia. A local wind speed maximum (~50 m s-1 ) embedded in this 250 hPa jet corridor contributed to the extreme intensity of the trailing (last) surface cyclone in the series. Although the dominant surface cyclone in the series of surface cyclones intensified most rapidly over the relatively ice free Arctic Ocean, the impact of surface heat and moisture fluxes appeared to be secondary to jet-driven dynamical processes in the deepening process. Anomalously high observed 1000-500 hPa thickness values between 564-570 dam, precipitable water values between 30-40 mm, and CAPE values between 500-1000 J kg-1 in the warm sector of the developing cyclone over north-central Russia were indicative of the enhanced baroclinicity and instability in the cyclone warm sector and the ability of lower tropospheric warm-air advection to sustain deep ascent in the intensifying cyclone. The relative importance of dynamical versus thermodynamical forcing to the cyclogenesis process as well as the bulk upscale effects of the intense cyclone on the larger scale higher-latitude circulation and the distribution of sea ice will be discussed. A noteworthy aspect of the post-storm polar environment was the upscale growth of a midlevel cyclonic circulation to include most of the Arctic Ocean. The off-pole displacement of this midlevel cyclonic circulation toward northern Canada by mid-August may have contributed to the termination of the 2012 summer-long intensive heat wave over most of the continental United States.

Tracing river runoff and DOC over the East Siberian Shelf using in situ CDOM measurements

NASA Astrophysics Data System (ADS)

Pugach, Svetlana; Semiletov, Igor; Pipko, Irina

2010-05-01

The Great Siberian Rivers integrate meteorological and hydrological changes in their watersheds and play a significant role in the physical and biogeochemical regime of the Arctic Ocean through transport of fresh water (FW) and carbon into the sea. Since 1994, the Laboratory of Arctic Research POI in cooperation with the IARC UAF investigate the fresh water and carbon fluxes in the Siberian Arctic land-shelf system with the special emphasize in the East Siberian Arctic shelf (ESAS) which represents the widest and shallowest continental shelf in the World Ocean, yet it is still poorly explored. The East Siberian Sea is influenced by water exchange from the eastern Laptev Sea (where local shelf waters are diluted mostly by Lena River discharge) and by inflow of Pacific waters from the Chukchi Sea. This region is characterized by the highest rate of coastal erosion and significant volume of the riverine discharge and exhibits the largest gradients in all oceanographic parameters observed for the entire Arctic Ocean. Here we demonstrate a connection among Chromophoric (or Colored) Dissolved Organic Matter (CDOM) which represents the colored fraction of Dissolved Organic Carbon (DOC), salinity, and pCO2. Our data have documented strong linear correlations between salinity and CDOM in the near shore zone strongly influenced by riverine runoff. Correlation coefficient between CDOM and salinity in surface waters was equal to -0.94, -0.94 and -0.95 for surface water stations in September of 2003, 2004, and 2005, respectively. Combined analysis of CDOM and DOC data demonstrated a high degree of correlation between these parameters (r=0.96). Such close connection between these characteristics of waters in this region makes it possible to restore the distribution of DOC according to our original CDOM data of the profiling systems, such as CTD-Seabird equipped by WETStar CDOM fluorimeter. It is shown that the CDOM can be used as a conservative tracer to follow the transport and fate of FW across the Arctic shelf through a combination of remote sensing and field observations. This work accomplished under auspice of the Russian Academy of Sciences, NOAA, US National Science Foundation, and Russian Foundation for Basic Research. Future work will be targeted towards a key, unresolved issue of climate change in the Arctic which can be cast as a scientific question that is fundamentally cross-disciplinary and synthetic: How does the Arctic hydrological and carbon cycle respond to global change?

Global GIS database; digital atlas of South Pacific

USGS Publications Warehouse

Hearn, P.P.; Hare, T.M.; Schruben, P.; Sherrill, D.; LaMar, C.; Tsushima, P.

2001-01-01

This CD-ROM contains a digital atlas of the countries of the South Pacific. This atlas is part of a global database compiled from USGS and other data sources at a nominal scale of 1:1 million and is intended to be used as a regional-scale reference and analytical tool by government officials, researchers, the private sector, and the general public. The atlas includes free GIS software or may be used with ESRI's ArcView software. Customized ArcView tools, specifically designed to make the atlas easier to use, are also included.

Dynamical downscaling with the fifth-generation Canadian regional climate model (CRCM5) over the CORDEX Arctic domain: effect of large-scale spectral nudging and of empirical correction of sea-surface temperature

NASA Astrophysics Data System (ADS)

Takhsha, Maryam; Nikiéma, Oumarou; Lucas-Picher, Philippe; Laprise, René; Hernández-Díaz, Leticia; Winger, Katja

2017-10-01

As part of the CORDEX project, the fifth-generation Canadian Regional Climate Model (CRCM5) is used over the Arctic for climate simulations driven by reanalyses and by the MPI-ESM-MR coupled global climate model (CGCM) under the RCP8.5 scenario. The CRCM5 shows adequate skills capturing general features of mean sea level pressure (MSLP) for all seasons. Evaluating 2-m temperature (T2m) and precipitation is more problematic, because of inconsistencies between observational reference datasets over the Arctic that suffer of a sparse distribution of weather stations. In our study, we additionally investigated the effect of large-scale spectral nudging (SN) on the hindcast simulation driven by reanalyses. The analysis shows that SN is effective in reducing the spring MSLP bias, but otherwise it has little impact. We have also conducted another experiment in which the CGCM-simulated sea-surface temperature (SST) is empirically corrected and used as lower boundary conditions over the ocean for an atmosphere-only global simulation (AGCM), which in turn provides the atmospheric lateral boundary conditions to drive the CRCM5 simulation. This approach, so-called 3-step approach of dynamical downscaling (CGCM-AGCM-RCM), which had considerably improved the CRCM5 historical simulations over Africa, exhibits reduced impact over the Arctic domain. The most notable positive effect over the Arctic is a reduction of the T2m bias over the North Pacific Ocean and the North Atlantic Ocean in all seasons. Future projections using this method are compared with the results obtained with the traditional 2-step dynamical downscaling (CGCM-RCM) to assess the impact of correcting systematic biases of SST upon future-climate projections. The future projections are mostly similar for the two methods, except for precipitation.

Is there a see-saw over an ice-free Arctic Ocean?

NASA Astrophysics Data System (ADS)

Stendel, Martin; Yang, Shuting; Langen, Peter; Rodehacke, Christian; Mottram, Ruth; Hesselbjerg Christensen, Jens

2017-04-01

The "see-saw" in winter temperatures between western Greenland and the Canadian Arctic on one side and northern Europe on the other has been described by Loewe already in 1937, but actually this behaviour was at least known since the Danish colonization of Greenland in the early 18th century. The see-saw is associated with pressure anomalies not only near the region of interest, but as remote as the Mediterranean and the North Pacific. Recent research has pointed out the role of sea ice in maintaining the see-saw in either its warm or its cold phase over extended periods, which strongly affects European winter temperatures. What would happen to the seesaw if Arctic sea ice were to disappear suddenly? In the framework of the FP7-funded project ice2ice, we try to answer this and related questions. We have conducted a very long global simulation with a global climate model interactively coupled to a Greenland ice sheet component, covering the period 1850-3250 at a horizontal resolution of approximately 125 km. Up to 2005, the forcing is from observed greenhouse gas concentrations, and from 2006 onward it follows the extended RCP8.5 scenario, in which greenhouse gas concentrations continue to increase and eventually level out around 2250. With such a strong forcing, all Arctic sea ice has completely disappeared by roughly the same time, and the surface mass balance of the Greenland Ice Sheet becomes strongly negative. We investigate how the see-saw behaves in such an ice-free world and which implications circulation changes have in the Arctic and over Europe. To further elucidate the role of sea ice distribution on the atmospheric flow and the role of surface fluxes in maintaining the Greenland-European see-saw, we intend at a later time to expand our analysis to include a contrasting simulation with both western Greenland and northern Europe covered by ice during the Last Glacier Maximum.

Radionuclides in the Arctic seas from the former Soviet Union: Potential health and ecological risks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Layton, D W; Edson, R; Varela, M

1999-11-15

The primary goal of the assessment reported here is to evaluate the health and environmental threat to coastal Alaska posed by radioactive-waste dumping in the Arctic and Northwest Pacific Oceans by the FSU. In particular, the FSU discarded 16 nuclear reactors from submarines and an icebreaker in the Kara Sea near the island of Novaya Zemlya, of which 6 contained spent nuclear fuel (SNF); disposed of liquid and solid wastes in the Sea of Japan; lost a {sup 90}Sr-powered radioisotope thermoelectric generator at sea in the Sea of Okhotsk; and disposed of liquid wastes at several sites in the Pacificmore » Ocean, east of the Kamchatka Peninsula. In addition to these known sources in the oceans, the RAIG evaluated FSU waste-disposal practices at inland weapons-development sites that have contaminated major rivers flowing into the Arctic Ocean. The RAIG evaluated these sources for the potential for release to the environment, transport, and impact to Alaskan ecosystems and peoples through a variety of scenarios, including a worst-case total instantaneous and simultaneous release of the sources under investigation. The risk-assessment process described in this report is applicable to and can be used by other circumpolar countries, with the addition of information about specific ecosystems and human life-styles. They can use the ANWAP risk-assessment framework and approach used by ONR to establish potential doses for Alaska, but add their own specific data sets about human and ecological factors. The ANWAP risk assessment addresses the following Russian wastes, media, and receptors: dumped nuclear submarines and icebreaker in Kara Sea--marine pathways; solid reactor parts in Sea of Japan and Pacific Ocean--marine pathways; thermoelectric generator in Sea of Okhotsk--marine pathways; current known aqueous wastes in Mayak reservoirs and Asanov Marshes--riverine to marine pathways; and Alaska as receptor. For these waste and source terms addressed, other pathways, such as atmospheric transport, could be considered under future-funded research efforts for impacts to Alaska. The ANWAP risk assessment does not address the following wastes, media, and receptors: radioactive sources in Alaska (except to add perspective for Russian source term); radioactive wastes associated with Russian naval military operations and decommissioning; Russian production reactor and spent-fuel reprocessing facilities nonaqueous source terms; atmospheric, terrestrial and nonaqueous pathways; and dose calculations for any circumpolar locality other than Alaska. These other, potentially serious sources of radioactivity to the Arctic environment, while outside the scope of the current ANWAP mandate, should be considered for future funding research efforts.« less

Tectonic map of the Circum-Pacific region, Pacific basin sheet

USGS Publications Warehouse

Scheibner, E.; Moore, G.W.; Drummond, K.J.; Dalziel, Corvalan Q.J.; Moritani, T.; Teraoka, Y.; Sato, T.; Craddock, C.

2013-01-01

Circum-Pacific Map Project: The Circum-Pacific Map Project was a cooperative international effort designed to show the relationship of known energy and mineral resources to the major geologic features of the Pacific basin and surrounding continental areas. Available geologic, mineral, and energy-resource data are being complemented by new, project-developed data sets such as magnetic lineations, seafloor mineral deposits, and seafloor sediment. Earth scientists representing some 180 organizations from more than 40 Pacific-region countries are involved in this work. Six overlapping equal-area regional maps at a scale of 1:10,000,000 form the cartographic base for the project: the four Circum-Pacific Quadrants (Northwest, Southwest, Southeast, and Northeast), and the Antarctic and Arctic Sheets. There is also a Pacific Basin Sheet at a scale of 1:17,000,000. The Base Map Series and the Geographic Series (published from 1977 to 1990), the Plate-Tectonic Series (published in 1981 and 1982), the Geodynamic Series (published in 1984 and 1985), and the Geologic Series (published from 1984 to 1989) all include six map sheets. Other thematic map series in preparation include Mineral-Resources, Energy-Resources and Tectonic Maps. Altogether, more than 50 map sheets are planned. The maps were prepared cooperatively by the Circum-Pacific Council for Energy and Mineral Resources and the U.S. Geological Survey and are available from the Branch of Distribution, U. S. Geological Survey, Box 25286, Federal Center, Denver, Colorado 80225, U.S.A. The Circum-Pacific Map Project is organized under six panels of geoscientists representing national earth-science organizations, universities, and natural-resource companies. The six panels correspond to the basic map areas. Current panel chairmen are Tomoyuki Moritani (Northwest Quadrant), R. Wally Johnson (Southwest Quadrant), Ian W.D. Dalziel (Antarctic Region), vacant. (Southeast Quadrant), Kenneth J. Drummond (Northeast Quadrant), and George W. Moore (Arctic Region). Project coordination and final cartography was being carried out through the cooperation of the Office of the Chief Geologist of the U.S. Geological Survey, under the direction of General Chairman, George Gryc of Menlo Park, California. Project headquarters were located at 345 Middlefield Road, MS 952, Menlo Park, California 94025, U.S.A. The framework for the Circum-Pacific Map Project was developed in 1973 by a specially convened group of 12 North American geoscientists meeting in California. The project was officially launched at the First Circum-Pacific Conference on Energy and Mineral Resources, which met in Honolulu, Hawaii, in August 1974. Sponsors of the conference were the AAPG, Pacific Science Association (PSA), and the Coordinating Committee for Offshore Prospecting for Mineral Resources in Offshore Asian Areas (CCOP). The Circum-Pacific Map Project operates as an activity of the Circum-Pacific Council for Energy and Mineral Resources, a nonprofit organization that promotes cooperation among Circum-Pacific countries in the study of energy and mineral resources of the Pacific basin. Founded by Michel T. Halbouty in 1972, the Council also sponsors conferences, topical symposia, workshops and the Earth Science Series books. Tectonic Map Series: The tectonic maps distinguish areas of oceanic and continental crust. Symbols in red mark active plate boundaries, and colored patterns show tectonic units (volcanic or magmatic arcs, arc-trench gaps, and interarc basins) associated with active plate margins. Well-documented inactive plate boundaries are shown by symbols in black. The tectonic development of oceanic crust is shown by episodes of seafloor spreading. These correlate with the rift and drift sequences at passive continental margins and episodes of tectonic activity at active plate margins. The recognized episodes of seafloor spreading seem to reflect major changes in plate kinematics. Oceanic plateaus and other prominences of greater than normal oceanic crustal thickness such as hotspot traces are also shown. Colored areas on the continents show the ages of deformation and metamorphism of basement rocks and the emplacement of igneous rocks. Transitional tectonic (molassic) and reactivation basins are shown by a colored boundary, and if they are deformed, a colored horizontal line pattern indicates the age of deformation. Colored bands along basin boundaries indicate age of inception, and isopachs indicate thickness of platform strata on continental crust and cover on oceanic crust. Colored patterns at separated continental margins show the age of inception of rift and drift (breakup) sequences. Symbols mark folds and faults, and special symbols show volcanoes and other structural features. Affiliations are as of compilation of the data. This map was created in quadrants and then compiled together. They are the Northwest land, Northwest Marine (different compilers), Northeast, Southwest and Southeast, and parts in plate-boundary sections.

Government bodies and their influence on the 2009 H1N1 health sector pandemic response in remote and isolated First Nation communities of sub-Arctic Ontario, Canada.

PubMed

Charania, N A; Tsuji, L J S

2011-01-01

First Nation communities were highly impacted by the 2009 H1N1 influenza pandemic. Multiple government bodies (ie federal, provincial, and First Nations) in Canada share responsibility for the health sector pandemic response in remote and isolated First Nation communities and this may have resulted in a fragmented pandemic response. This study aimed to discover if and how the dichotomy (or trichotomy) of involved government bodies led to barriers faced and opportunities for improvement during the health sector response to the 2009 H1N1 pandemic in three remote and isolated sub-arctic First Nation communities of northern Ontario, Canada. A qualitative community-based participatory approach was employed. Semi-directed interviews were conducted with adult key informants (n=13) using purposive sampling of participants representing the two (or three) government bodies of each study community. Data were manually transcribed and coded using deductive and inductive thematic analysis to reveal positive aspects, barriers faced, and opportunities for improvement along with the similarities and differences regarding the pandemic responses of each government body. Primary barriers faced by participants included receiving contradicting governmental guidelines and direction from many sources. In addition, there was a lack of human resources, information sharing, and specific details included in community-level pandemic plans. Recommended areas of improvement include developing a complementary communication plan, increasing human resources, and updating community-level pandemic plans. Participants reported many issues that may be attributable to the dichotomy (or trichotomy) of government bodies responsible for healthcare delivery during a pandemic. Increasing formal communication and collaboration between responsible government bodies will assist in clarifying roles and responsibilities and improve the pandemic response in Canada's remote and isolated First Nation communities.

Remote and Local Influences in Forecasting Pacific SST: a Linear Inverse Model and a Multimodel Ensemble Study

NASA Astrophysics Data System (ADS)

Faggiani Dias, D.; Subramanian, A. C.; Zanna, L.; Miller, A. J.

2017-12-01

Sea surface temperature (SST) in the Pacific sector is well known to vary on time scales from seasonal to decadal, and the ability to predict these SST fluctuations has many societal and economical benefits. Therefore, we use a suite of statistical linear inverse models (LIMs) to understand the remote and local SST variability that influences SST predictions over the North Pacific region and further improve our understanding on how the long-observed SST record can help better guide multi-model ensemble forecasts. Observed monthly SST anomalies in the Pacific sector (between 15oS and 60oN) are used to construct different regional LIMs for seasonal to decadal prediction. The forecast skills of the LIMs are compared to that from two operational forecast systems in the North American Multi-Model Ensemble (NMME) revealing that the LIM has better skill in the Northeastern Pacific than NMME models. The LIM is also found to have comparable forecast skill for SST in the Tropical Pacific with NMME models. This skill, however, is highly dependent on the initialization month, with forecasts initialized during the summer having better skill than those initialized during the winter. The forecast skill with LIM is also influenced by the verification period utilized to make the predictions, likely due to the changing character of El Niño in the 20th century. The North Pacific seems to be a source of predictability for the Tropics on seasonal to interannual time scales, while the Tropics act to worsen the skill for the forecast in the North Pacific. The data were also bandpassed into seasonal, interannual and decadal time scales to identify the relationships between time scales using the structure of the propagator matrix. For the decadal component, this coupling occurs the other way around: Tropics seem to be a source of predictability for the Extratropics, but the Extratropics don't improve the predictability for the Tropics. These results indicate the importance of temporal scale interactions in improving predictability on decadal timescales. Hence, we show that LIMs are not only useful as benchmarks for estimates of statistical skill, but also to isolate contributions to the forecast skills from different timescales, spatial scales or even model components.

The radiocarbon reservoir age of the Chukchi Sea, Arctic Ocean

NASA Astrophysics Data System (ADS)

Pearce, C.; Gyllencreutz, R.; West, G.; O'Regan, M.; Jakobsson, M.

2017-12-01

Radiocarbon (14C) dating is the standard method for obtaining the age of marine sediments of Holocene and late Pleistocene age. For accurate calibrations, however, this tool relies on precise knowledge of the local radiocarbon reservoir age of the surface ocean, i.e. the regional difference (ΔR) from the average global marine calibration dataset. This parameter has become impossible to measure from modern mollusk samples because of 14C contamination from extensive testing of thermo-nuclear bombs in the second half of the twentieth century. The local reservoir age can thus only be calculated from the radiocarbon age of samples collected before AD 1950 or from sediment records containing absolute age markers, derived from e.g. tephrochronology or paleomagnetism. Knowledge of the marine reservoir age in the Arctic Ocean is extremely sparse, and relies on work by only a few studies. No information exists for the entire East Siberian Sea, and the Chukchi Sea is represented solely by sites along the Alaskan coast. Here we present new radiocarbon measurements on historical mollusk collections from the East Siberian and Chukchi margins. Our results show a clear and consistent signal of "old" Pacific Water in the Chukchi Sea with ΔR values around 450 years. Towards the East Siberian Sea the values drop as Pacific Water has decreased influence further away from the Bering Strait. Complementing the modern data, we also provide constraints on the reservoir age during the late Holocene. These are based on tephrochronology and high resolution analyses of paleomagnetic secular variation from a sediment archive from Herald Canyon, Chukchi Sea.

Climate impacts on transocean dispersal and habitat in gray whales from the Pleistocene to 2100.

PubMed

Alter, S Elizabeth; Meyer, Matthias; Post, Klaas; Czechowski, Paul; Gravlund, Peter; Gaines, Cork; Rosenbaum, Howard C; Kaschner, Kristin; Turvey, Samuel T; van der Plicht, Johannes; Shapiro, Beth; Hofreiter, Michael

2015-04-01

Arctic animals face dramatic habitat alteration due to ongoing climate change. Understanding how such species have responded to past glacial cycles can help us forecast their response to today's changing climate. Gray whales are among those marine species likely to be strongly affected by Arctic climate change, but a thorough analysis of past climate impacts on this species has been complicated by lack of information about an extinct population in the Atlantic. While little is known about the history of Atlantic gray whales or their relationship to the extant Pacific population, the extirpation of the Atlantic population during historical times has been attributed to whaling. We used a combination of ancient and modern DNA, radiocarbon dating and predictive habitat modelling to better understand the distribution of gray whales during the Pleistocene and Holocene. Our results reveal that dispersal between the Pacific and Atlantic was climate dependent and occurred both during the Pleistocene prior to the last glacial period and the early Holocene immediately following the opening of the Bering Strait. Genetic diversity in the Atlantic declined over an extended interval that predates the period of intensive commercial whaling, indicating this decline may have been precipitated by Holocene climate or other ecological causes. These first genetic data for Atlantic gray whales, particularly when combined with predictive habitat models for the year 2100, suggest that two recent sightings of gray whales in the Atlantic may represent the beginning of the expansion of this species' habitat beyond its currently realized range. © 2015 John Wiley & Sons Ltd.

Nitrification and its influence on biogeochemical cycles from the equatorial Pacific to the Arctic Ocean

PubMed Central

Shiozaki, Takuhei; Ijichi, Minoru; Isobe, Kazuo; Hashihama, Fuminori; Nakamura, Ken-ichi; Ehama, Makoto; Hayashizaki, Ken-ichi; Takahashi, Kazutaka; Hamasaki, Koji; Furuya, Ken

2016-01-01

We examined nitrification in the euphotic zone, its impact on the nitrogen cycles, and the controlling factors along a 7500 km transect from the equatorial Pacific Ocean to the Arctic Ocean. Ammonia oxidation occurred in the euphotic zone at most of the stations. The gene and transcript abundances for ammonia oxidation indicated that the shallow clade archaea were the major ammonia oxidizers throughout the study regions. Ammonia oxidation accounted for up to 87.4% (average 55.6%) of the rate of nitrate assimilation in the subtropical oligotrophic region. However, in the shallow Bering and Chukchi sea shelves (bottom ⩽67 m), the percentage was small (0–4.74%) because ammonia oxidation and the abundance of ammonia oxidizers were low, the light environment being one possible explanation for the low activity. With the exception of the shallow bottom stations, depth-integrated ammonia oxidation was positively correlated with depth-integrated primary production. Ammonia oxidation was low in the high-nutrient low-chlorophyll subarctic region and high in the Bering Sea Green Belt, and primary production in both was influenced by micronutrient supply. An ammonium kinetics experiment demonstrated that ammonia oxidation did not increase significantly with the addition of 31–1560 nm ammonium at most stations except in the Bering Sea Green Belt. Thus, the relationship between ammonia oxidation and primary production does not simply indicate that ammonia oxidation increased with ammonium supply through decomposition of organic matter produced by primary production but that ammonia oxidation might also be controlled by micronutrient availability as with primary production. PMID:26918664

Genomics of Arctic cod

USGS Publications Warehouse

Wilson, Robert E.; Sage, George K.; Sonsthagen, Sarah A.; Gravley, Megan C.; Menning, Damian; Talbot, Sandra L.

2017-01-01

The Arctic cod (Boreogadus saida) is an abundant marine fish that plays a vital role in the marine food web. To better understand the population genetic structure and the role of natural selection acting on the maternally-inherited mitochondrial genome (mitogenome), a molecule often associated with adaptations to temperature, we analyzed genetic data collected from 11 biparentally-inherited nuclear microsatellite DNA loci and nucleotide sequence data from from the mitochondrial DNA (mtDNA) cytochrome b (cytb) gene and, for a subset of individuals, the entire mitogenome. In addition, due to potential of species misidentification with morphologically similar Polar cod (Arctogadus glacialis), we used ddRAD-Seq data to determine the level of divergence between species and identify species-specific markers. Based on the findings presented here, Arctic cod across the Pacific Arctic (Bering, Chukchi, and Beaufort Seas) comprise a single panmictic population with high genetic diversity compared to other gadids. High genetic diversity was indicated across all 13 protein-coding genes in the mitogenome. In addition, we found moderate levels of genetic diversity in the nuclear microsatellite loci, with highest diversity found in the Chukchi Sea. Our analyses of markers from both marker classes (nuclear microsatellite fragment data and mtDNA cytb sequence data) failed to uncover a signal of microgeographic genetic structure within Arctic cod across the three regions, within the Alaskan Beaufort Sea, or between near-shore or offshore habitats. Further, data from a subset of mitogenomes revealed no genetic differentiation between Bering, Chukchi, and Beaufort seas populations for Arctic cod, Saffron cod (Eleginus gracilis), or Walleye pollock (Gadus chalcogrammus). However, we uncovered significant differences in the distribution of microsatellite alleles between the southern Chukchi and central and eastern Beaufort Sea samples of Arctic cod. Finally, using ddRAD-Seq data, we identified species-specific markers and in conjunction with mitogenome data, identified an Arctic cod x Polar cod hybrid in western Canadian Beaufort Sea. Overall, the lack of genetic structure among Arctic cod within the Bering, Chukchi and Beaufort seas of Alaska is concordant with the absence of geographic barriers to dispersal and typical among marine fishes. Arctic cod may exhibit a genetic pattern of isolation-by-distance, whereby populations in closer geographic proximity are more genetically similar than more distant populations. As this signal is only found between our two fartherest localities, data from populations elsewhere in the species’ global range are needed to determine if this is a general characteristic. Further, tests for selection suggested a limited role for natural selection acting on the mitochondrial genome of Arctic cod, but do not exclude the possibility of selection on genes involved in nuclear-mitogenome interactions. Unlike previous genetic assessment of Arctic cod sampled from the Chukchi Sea, the high levels of genetic diversity found in Arctic cod assayed in this study, across regions, suggests that the species in the Beaufort and Chukchi seas does not suffer from low levels of genetic variation, at least at neutral genetic markers. The large census size of Arctic cod may allow this species to retain high levels of genetic diversity. In addition, we discovered the presence of hybridization between Arctic and Polar cod (although low in frequency). Hybridization is expected to occur when environmental changes modify species distributions that result in contact between species that were previously separated. In such cases, hybridization may be an evolutionary mechanism that promotes an increase in genetic diversity that may provide species occupying changing environments with locally-adapted genotypes and, therefore, phenotypes. Natural selection can only act on the standing genetic variation present within a population. Therefore, given its higher levels of genetic diversity in combination with a large population size, Arctic cod may be resilient to current and future environmental change, as high genetic diversity is expected to increase opportunities for positive selection to act on genetic variants beneficial in different environments, regardless of the source of that genetic variation.

Arctic and Tropical Influence on Extreme Precipitation Events, Atmospheric Rivers, and Associated Isotopic Values in the Western U.S.

NASA Astrophysics Data System (ADS)

McCabe-Glynn, S. E.; Johnson, K. R.; Zou, Y.; Welker, J. M.; Strong, C.; Rutz, J. J.; Yu, J. Y.; Yoshimura, K.; Sellars, S. L.; Payne, A. E.

2014-12-01

Extreme precipitation events along the U.S. West Coast can result in major damage and are projected by most climate models to increase in frequency and severity. One of the most prevalent extreme precipitation events that occurs along the west coast of North America are known as 'Atmospheric Rivers' (ARs), whereby extensive fluxes of water vapor are transported from the tropics and/or subtropics, delivering substantial precipitation and contributing to flooding when they encounter mountains. This region is particularly vulnerable to ARs, with 30-50% of annual precipitation in this region occurring from just a few AR events. Because of the tropical and/or subtropical origin of ARs, they can carry unique isotopic properties. Here we present the results of analysis of weekly precipitation data and accompanying isotopic values from Giant Forest, in Sequoia National Park, in the southwestern Sierra Nevada Mountains (36.57° N; 118.78° W; 1921m) from 2001 to 2011. To better characterize these events, we focused on the 10 weeks with the highest precipitation totals (all greater than 150 mm) during the study period. We show that nine of the top ten weeks contain documented 'AR' events and that 90% occurred during the negative phase of the Arctic Oscillation. A comparison of extreme precipitation events across the Western U.S. with several key climate indices demonstrate these events occur most frequently when the negative phase of the Arctic Oscillation is in sync with the negative phase of the El Niño Southern Oscillation (ENSO) and the negative or neutral Pacific North American (PNA) pattern. We also demonstrate that central or eastern Pacific location of ENSO sea surface temperature anomalies can further enhance predictive capabilities of the landfall location of extreme precipitation. Stable isotope results show that extreme precipitation events are characterized by highly variable δ18O (-7.20‰ to -19.27‰), however, we find that more negative δ18O values typically occur during the negative PNA pattern. Finally, we will present the results of data comparison with NCAR-NCEP reanalysis, Hysplit back trajectories, and isotope enabled climate model (IsoGSM) results.

Tracking Biological and Ecosystem Responses to Changing Environmental Conditions in the Pacific Arctic

NASA Astrophysics Data System (ADS)

Grebmeier, J. M.; Cooper, L. W.; Frey, K. E.; Moore, S. E.

2014-12-01

Changing seasonal sea ice conditions and seawater temperatures strongly influence biological processes and marine ecosystems at high latitudes. In the Pacific Arctic, persistent regions termed "hotspots", are localized areas with high benthic macroinfaunal biomass that have been documented over four decades (see Figure). These regions are now being more formally tracked to relate physical forcing and ecosystem response as an Arctic Distributed Biological Observatory (DBO) supported by the US National Ocean Policy Implementation Plan and international partners. These hotspots are important foraging areas for upper trophic level benthic feeders, such as marine mammals and seabirds. South of St. Lawrence Island (SLI) in the northern Bering Sea, benthic feeding spectacled eiders, bearded seals and walruses are important winter consumers of infauna, such as bivalves and polychaetes. Gray whales have historically been a major summer consumer of benthic amphipods in the Chirikov Basin to the north of SLI, although summertime sightings of gray whales declined in the Chirikov from the 1980s up until at least 2002. The SE Chukchi Sea hotspot, as are the other hotspots, is maintained by export of high chlorophyll a that is produced locally as well as advected by water masses transiting northward through the system. Both walrus and gray whales are known to forage in this hotspot seasonally on high biomass levels of benthic prey. Notably the center of the highest benthic biomass regions has shifted northward in three of the DBO hotspots in recent years. This has coincided with changing sediment grain size, an indicator of current speed, and is also likely a response to changes in primary production in the region. Studies of these broad biological responses to changing physical drivers have been facilitated through development of the DBO cooperative effort by both US and international scientists. The DBO includes a series of coordinated, multi-trophic level observations that integrate physical, biogeochemical and biological measurements along transect lines that intersect all of the benthic hotspots. We will highlight results at three of the DBO time-series sites from the northern Bering Sea to the SE Chukchi Sea in relation to retrospective and ongoing process-oriented studies in the region.

KALMAR - "Kurile-Kamchatka and Aleutean Marginal Sea-Island Arc Systems: Geodynamic and Climate Interaction in Space and Time" - an integrated science approach between Russia and Germany

NASA Astrophysics Data System (ADS)

Dullo, Wolf-Christian; Baranov, Boris; van den Bogaard, Christel

2010-05-01

The exploration of the arctic seas require an integrated approach applying different infrastructures. In Fall 2009 German and Russian scientists performed a geo marine cruise off Kamchatka and in the western Bering Sea within the frame of the KALMAR-Project. Two main research subjects formed the scientific backbone of the cruise: The first objective focuses on the geodynamic and volcanological-magmatic development of the Kuril-Kamchatka island arc system and the Kamchatka Aleutean Islands Triple-Junction. Very little is known about the composition of the mantle and the oceanic crust as well as of the seamounts including their ages. The best studied site is the Volcanologist's Massif located between the Bering- and the Alpha Fracture Zone (Tsvetkov 1990, Volynets et al. 1992, Yogodzinsky et al. 1994), which structurally belongs to the Komandorsky Basin. The oldest rocks of the Volcanologist's Massif show very similar trace element and isotope signatures like those rocks cropping out in the volcanoes on Kamchatka in the prolongation of the Alpha Fracture Zone (Portnyagin et al. 2005a), indicating similar conditions of magma formation. The top of the Volcanologist's Massif is characterized by the young (< 0.5 Ma) and hydrothermally active Piip volcano, which consists of special magnesium rich andesites ("Piip type"). Another hot site was the Meiji-Seamount which is the northernmost Seamount of the hotspot spur of the Hawaii-Emperor-Seamount chain, having an age of probably > 85 Ma. The only existing basement rocks from this seamount were gained during DSDP Leg 19. These are basalts with MORB like trace element and isotope signatures (Keller et al. 2000, Regelous et al. 2003). These data indicate that the Hawaii-Hotspot was at a MOR in Cretaceous time and that large volumes of depleted mantle material played a role during the magma formation. The second objective focuses on paleo-oceanographic investigations concentrating on the sediments along the eastern continental slope of Kamchatka, in the Komandorsky Basin, and on the Shirshov Ridge in order to explore paleoclimate archives to better understand the subpolar water mass transfer and the oceanographic and climatic development in the subarctic NW-Pacific. Comparisons of Late Pleistocene and Holocene temperature changes within the near surface water masses between the NW-Pacific and the N-Atlantic resulted in a new hypothesis, the "Atlantic-Pacific seesaw" (Kiefer et al. 2001, Kim et al. 2004, Kiefer and Kienast, 2005). This Atlantic-Pacific pattern of opposite temperature variations dominates the last 60ka on millennial timescales. Modelling results of Saenko et al. (2004) support the hypothesis of the "Atlantic-Pacific seesaw" and they postulate a mechanistic connection between the two regions driven by salinity variations, which couples both regions through the thermohaline circulation. A different model relates the Holocene Atlantic-Pacific dipole to the atmospheric tele-connection between the Arctic Oscillation/N-Atlantic Oscillation and the Pacific N-American Oscillation (Kim et al. 2004). http://kalmar.ifm-geomar.de

Using trajectories to explain the moisture budget asymmetry between the Atlantic and Pacific Oceans

NASA Astrophysics Data System (ADS)

Craig, P.; Ferreira, D.; Methven, J.

2017-12-01

The net surface water flux (evaporation minus precipitation minus runoff, E-P-R) of the Atlantic Ocean is approximately 0.4 - 0.6 Sv (1 Sv = 109 kg s-1) larger than that of the Pacific Ocean, as shown in atmospheric and oceanic reanalyses and by oceanographic estimates. This asymmetry is linked to the asymmetry in sea surface salinity and the existence of the Atlantic Meridional Overturning Circulation. It is shown that the reason for the asymmetry in E-P-R is greater precipitation per unit area over the Pacific south of 30N, while evaporation rates are similar over both basins. It is further argued that the Pacific Ocean is anomalous compared to the Atlantic and Indian Oceans in terms of atmospheric moisture flux convergence and precipitation across the tropics and subtropics. To clarify the mechanism by which water vapour is exported out of the Atlantic basin and imported into the Pacific, we use an air mass trajectory model driven by ERA-Interim reanalysis. Using 12-hourly releases of 14-day back trajectories on the boundaries of ocean drainage basins over the period 2010-2014, we are able to partition the atmospheric moisture fluxes between basins according to their origins (i.e. last contact with the boundary layer). We show that at most a quarter of the E-P-R asymmetry is explained by higher moisture export to the Arctic and Southern basins from the Atlantic than from the Pacific. The main contributions come from differences in the longitudinal atmospheric transport of moisture between the Atlantic, Indian and Pacific basins. In particular, during the Asian summer monsoon the recurvature of the low level flow in the Somali Jet results in a much weaker westward moisture transport from the Indian into the Atlantic basin than across Central America (where it is similar to the zonal average) while there is stronger eastward transport from the Indian to Pacific basins. The net effect is stronger moisture convergence into the Pacific, but weaker into the Atlantic. In contrast to previous thinking, the role of the moisture flux across Central America in the asymmetry, albeit significant, is not dominant.

Assessing the vulnerability of infrastructure to climate change on the Islands of Samoa

NASA Astrophysics Data System (ADS)

Fakhruddin, S. H. M.

2015-03-01

Pacific Islanders have been exposed to risks associated with climate change. Samoa as one of the Pacific Islands are prone to climatic hazards that will likely increase in coming decades, affecting coastal communities and infrastructure around the islands. Climate models do not predict a reduction of such disaster events in the future in Samoa; indeed, most predict an increase in such events. This paper identifies key infrastructure and their functions and status in order to provide an overall picture of relative vulnerability to climate-related stresses of such infrastructure on the island. By reviewing existing reports as well as holding a series of consultation meetings, a list of critical infrastructures were developed and shared with stakeholders for their consideration. An indicator-based vulnerability model (SIVM) was developed in collaboration with stakeholders to assess the vulnerability of selected infrastructure systems on the Samoan Islands. Damage costs were extracted from the Evan cyclone recovery needs document. On the other hand, criticality and capacity to repair data were collected from stakeholders. Having stakeholder perspectives on these two issues was important because (a) criticality of a given infrastructure could be viewed differently among different stakeholders, and (b) stakeholders were the best available source (in this study) to estimate the capacity to repair non-physical damage to such infrastructure. Analysis of the results suggested rankings from most vulnerable to least vulnerable sectors are the transportation sector, the power sector, the water supply sector and the sewerage system.

Assessing the vulnerability of infrastructure to climate change on the Islands of Samoa

NASA Astrophysics Data System (ADS)

Fakhruddin, S. H. M.; Babel, M. S.; Kawasaki, A.

2015-06-01

Pacific Islanders have been exposed to risks associated with climate change. Samoa, as one of the Pacific Islands, is prone to climatic hazards that will likely increase in the coming decades, affecting coastal communities and infrastructure around the islands. Climate models do not predict a reduction of such disaster events in the future in Samoa; indeed, most predict an increase. This paper identifies key infrastructure and their functions and status in order to provide an overall picture of relative vulnerability to climate-related stresses of such infrastructure on the island. By reviewing existing reports as well as holding a series of consultation meetings, a list of critical infrastructure was developed and shared with stakeholders for their consideration. An indicator-based vulnerability model (SIVM) was developed in collaboration with stakeholders to assess the vulnerability of selected infrastructure systems on the Samoan Islands. Damage costs were extracted from the Cyclone Evan recovery needs document. Additionally, data on criticality and capacity to repair damage were collected from stakeholders. Having stakeholder perspectives on these two issues was important because (a) criticality of a given infrastructure could be viewed differently among different stakeholders, and (b) stakeholders were the best available source (in this study) to estimate the capacity to repair non-physical damage to such infrastructure. Analysis of the results suggested a ranking of sectors from the most vulnerable to least vulnerable are: the transportation sector, the power sector, the water supply sector and the sewerage system.

Public sector refraction and spectacle dispensing in low-resource countries of the Western Pacific.

PubMed

Ramke, Jacqueline; du Toit, Rènée; Palagyi, Anna; Williams, Carmel; Brian, Garry

2008-05-01

Given that uncorrected refractive error is a frequent cause of vision impairment, and that there is a high unmet need for spectacles, an appraisal of public sector arrangements for the correction of refractive error was conducted in eight Pacific Island countries. Mixed methods (questionnaire and semi-structured interviews) were used to collect information from eye care personnel (from Fiji, Papua New Guinea, Solomon Islands, Vanuatu, Cook Islands, Samoa, Tonga and Tuvalu) attending a regional eye health workshop in 2005. Fiji, Tonga and Vanuatu had Vision 2020 eye care plans that included refraction services, but not spectacle provision. There was wide variation in public sector spectacle dispensing services, but, except in Samoa, ready-made spectacles and a full cost recovery pricing strategy were the mainstay. There were no systems for the registration of personnel, nor guidelines for clinical or systems management. The refraction staff to population ratio varied considerably. Solomon Islands, Tuvalu and Vanuatu had the best coverage by services, either fixed or outreach. Most services had little promotional activity or community engagement. To be successful, it would seem that public sector refraction services should answer a real and perceived need, fit within prevailing policy and legislation, value, train, retain and equip employees, be well managed, be accessible and affordable, be responsive to consumers, and provide ongoing good quality outcomes. To this end, a checklist to aid the initiation and maintenance of refraction and spectacle systems in low-resource countries has been constructed.

Mid-latitude thermospheric dynamics from an inter-hemispheric prospective

NASA Astrophysics Data System (ADS)

Wu, Q.; Wang, W.; Li, T.; Huang, C.; Zhang, X.; McCarthy, M.; Noto, J.; Kerr, R.

2017-12-01

Mid-latitude thermosphere is strongly affected by mesospheric tides and geomagnetic latitude variations. Past mid-latitude observations are mostly from the northern hemisphere. Only recently, thermospheric wind instruments are being deployed in the southern mid-latitude regions. In this study, we will examine simultaneous northern and southern mid-latitude thermospheric winds and investigate how seasonal and geomagnetic latitude differences affecting the thermospheric winds. We will use thermospheric winds from two southern Fabry-Perot interferometers (FPI) at Palmer (64°S, 64°W, MLAT 54°S) and Mt. John (44°S, 170.5°E, MLAT 47.5°S) and compare to three northern FPIs at Millstone Hill (42°N, 71°W, MLAT 52°N), Boulder (40°N, 105°W, MLAT 47°N), and Kelan (38.7°N, 111.6°E, MLAT 28.9°N). These instruments distributed in both the American and Asia-Pacific sectors. In the American sector northern hemisphere and the Asia-Pacific sector southern hemisphere, the geomagnetic latitude is larger than the geographic. In each of the respective opposite the hemisphere, the geographic latitude is larger than the geomagnetic. Observations in these two longitudinal sectors with opposite geomagnetic and geographic offsets will allow us to examine the magnetic latitude and seasonal effects in greater details. We will compare the observations with NCAR TIEGCM simulations to perform an inter-hemispheric comparison of the mid-latitude thermospheric dynamics.

Relationship between eastern tropical Pacific cooling and recent trends in the Southern Hemisphere zonal-mean circulation

NASA Astrophysics Data System (ADS)

Clem, Kyle R.; Renwick, James A.; McGregor, James

2017-07-01

During 1979-2014, eastern tropical Pacific sea surface temperatures significantly cooled, which has generally been attributed to the transition of the Pacific Decadal Oscillation to its negative phase after 1999. We find the eastern tropical Pacific cooling to be associated with: (1) an intensified Walker Circulation during austral summer (December-February, DJF) and autumn (March-May, MAM); (2) a weakened South Pacific Hadley cell and subtropical jet during MAM; and (3) a strengthening of the circumpolar westerlies between 50 and 60°S during DJF and MAM. Observed cooling in the eastern tropical Pacific is linearly congruent with 60-80 % of the observed Southern Hemisphere positive zonal-mean zonal wind trend between 50 and 60°S during DJF ( 35 % of the interannual variability), and around half of the observed positive zonal-mean zonal wind trend during MAM ( 15 % of the interannual variability). Although previous studies have linked the strengthened DJF and MAM circumpolar westerlies to stratospheric ozone depletion and increasing greenhouse gases, we note that the continuation of the positive SAM trends into the twenty-first century is partially associated with eastern tropical Pacific cooling, especially during MAM when zonal wind anomalies associated with eastern tropical Pacific cooling project strongly onto the observed trends. Outside of DJF and MAM, eastern tropical Pacific cooling is associated with opposing zonal wind anomalies over the Pacific and Indian sectors, which we infer is the reason for the absence of significant positive SAM trends outside of DJF and MAM despite significant eastern tropical Pacific cooling seen during all seasons.

Northern Regions of Russia as Alternative Sources of Pure Water for Sustainable Development: Challenges and Solutions

NASA Astrophysics Data System (ADS)

Tsukerman, V. A.; Gudkov, A. V.; Ivanov, S. V.

The paper discusses problems associated with the existing crisis of water scarcity in the modern conditions of the global water use. Available alternative sources of fresh water may be underground and surface waters of the North and the Arctic. Investigated the current situation and condition of fresh water resources in the technological and industrial development of the North and Arctic. The necessity of developing and using green technologies and measures to prevent pollution of surface and ground water from industrial sectors of the Northern regions is shown. Studied modern technologies and techniques for monitoring groundwater and determination of their age in order to avoid and prevent the effects of environmental contaminants. The ways of use of innovative production technologies of fresh and clean water of north Russia for sustainable development, and delivery of water in the needy regions of the world are investigated.

Informatics and computational method for inundation and land use study in Arctic Sea eastern Siberia, Russia

NASA Astrophysics Data System (ADS)

Boori, Mukesh Singh; Choudhary, Komal; Kupriyanov, Alexander; Sugimoto, Atsuko

2016-11-01

Eastern Siberia, Russia is physically and socio-economically vulnerable to accelerated Arctic sea level rise due to low topography, high ecological value, harsh climatic conditions, erosion and flooding of coastal area and destruction of harbor constructions and natural coastal hazards. A 1 to 10m inundation land loss scenarios for surface water and sea level rise (SLR) were developed using digital elevation models of study site topography through remote sensing and GIS techniques by ASTER GDEM and Landsat OLI data. Results indicate that 10.82% (8072.70km2) and 29.73% (22181.19km2) of the area will be lost by flooding at minimum and maximum inundation levels, respectively. The most severely impacted sectors are expected to be the vegetation, wetland and the natural ecosystem. Improved understanding of the extent and response of SLR will help in preparing for mitigation and adaptation.

Understanding, representing and communicating earth system processes in weather and climate within CNRCWP

NASA Astrophysics Data System (ADS)

Sushama, Laxmi; Arora, Vivek; de Elia, Ramon; Déry, Stephen; Duguay, Claude; Gachon, Philippe; Gyakum, John; Laprise, René; Marshall, Shawn; Monahan, Adam; Scinocca, John; Thériault, Julie; Verseghy, Diana; Zwiers, Francis

2017-04-01

The Canadian Network for Regional Climate and Weather Processes (CNRCWP) provides significant advances and innovative research towards the ultimate goal of reducing uncertainty in numerical weather prediction and climate projections for Canada's Northern and Arctic regions. This talk will provide an overview of the Network and selected results related to the assessment of the added value of high-resolution modelling that has helped fill critical knowledge gaps in understanding the dynamics of extreme temperature and precipitation events and the complex land-atmosphere interactions and feedbacks in Canada's northern and Arctic regions. In addition, targeted developments in the Canadian regional climate model, that facilitate direct application of model outputs in impact and adaptation studies, particularly those related to the water, energy and infrastructure sectors will also be discussed. The close collaboration between the Network and its partners and end users contributed significantly to this effort.

Modification of the deep salinity-maximum in the Southern Ocean by circulation in the Antarctic Circumpolar Current and the Weddell Gyre

NASA Astrophysics Data System (ADS)

Donnelly, Matthew; Leach, Harry; Strass, Volker

2017-07-01

The evolution of the deep salinity-maximum associated with the Lower Circumpolar Deep Water (LCDW) is assessed using a set of 37 hydrographic sections collected over a 20-year period in the Southern Ocean as part of the WOCE/CLIVAR programme. A circumpolar decrease in the value of the salinity-maximum is observed eastwards from the North Atlantic Deep Water (NADW) in the Atlantic sector of the Southern Ocean through the Indian and Pacific sectors to Drake Passage. Isopycnal mixing processes are limited by circumpolar fronts, and in the Atlantic sector, this acts to limit the direct poleward propagation of the salinity signal. Limited entrainment occurs into the Weddell Gyre, with LCDW entering primarily through the eddy-dominated eastern limb. A vertical mixing coefficient, κV of (2.86 ± 1.06) × 10-4 m2 s-1 and an isopycnal mixing coefficient, κI of (8.97 ± 1.67) × 102 m2 s-1 are calculated for the eastern Indian and Pacific sectors of the Antarctic Circumpolar Current (ACC). A κV of (2.39 ± 2.83) × 10-5 m2 s-1, an order of magnitude smaller, and a κI of (2.47 ± 0.63) × 102 m2 s-1, three times smaller, are calculated for the southern and eastern Weddell Gyre reflecting a more turbulent regime in the ACC and a less turbulent regime in the Weddell Gyre. In agreement with other studies, we conclude that the ACC acts as a barrier to direct meridional transport and mixing in the Atlantic sector evidenced by the eastward propagation of the deep salinity-maximum signal, insulating the Weddell Gyre from short-term changes in NADW characteristics.

Thermal ecotypes of amphi-Atlantic algae. I. Algae of Arctic to cold-temperate distribution ( Chaetomorpha melagonium, Devaleraea ramentacea and Phycodrys rubens)

NASA Astrophysics Data System (ADS)

Novaczek, I.; Lubbers, G. W.; Breeman, A. M.

1990-09-01

Three species of Arctic to cold-temperate amphi-Atlantic algae, all occurring also in the North Pacific, were tested for growth and/or survival at temperatures of -20 to 30°C. When isolates from both western and eastern Atlantic shores were tested side-by-side, it was found that thermal ecotypes may occur in such Arctic algae. Chaetomorpha melagonium was the most eurythermal of the 3 species. Isolates of this alga were alike in temperature tolerance and growth rate but Icelandic plants were more sensitive to the lethal temperature of 25°C than were more southerly isolates from both east and west. With regard to Devaleraea ramentacea, one Canadian isolate grew extraordinarily well at -2 and 0°C, and all tolerated temperatures 2 3°C higher than the lethal limit (18 20°C) of isolates from Europe. Concerning Phycodrys rubens, both eastern and western isolates died at 20°C but European plants tolerated the lethal high temperature longer, were more sensitive to freezing, and attained more rapid growth at optimal temperatures. The intertidal species, C. melagonium and D. ramentacea, both survived freezing at -5 and -20°C, at least for short time periods. C. melagonium was more susceptible than D. ramentacea to desiccation. Patterns of thermal tolerance may provide insight into the evolutionary history of seaweed species.

Increases in the Pacific inflow to the Arctic from 1990 to 2015, and insights into seasonal trends and driving mechanisms from year-round Bering Strait mooring data

NASA Astrophysics Data System (ADS)

Woodgate, Rebecca A.

2018-01-01

Year-round in situ Bering Strait mooring data (1990-2015) document a long-term increase (∼0.01 Sv/yr) in the annual mean transport of Pacific waters into the Arctic. Between 2002 and 2015, all annual mean transports (except 2005 and 2012) are greater than the previously accepted climatology (∼0.8 Sv). The record-length maximum (2014: 1.2 ± 0.1 Sv) is 70% higher than the record-length minimum (2001: 0.7 ± 0.1 Sv), corresponding to a reduction in the flushing time of the Chukchi Sea (to ∼4.5 months from ∼7.5 months). The transport increase results from stronger northward flows (not fewer southward flow events), yielding a 150% increase in kinetic energy, presumably with impacts on bottom suspension, mixing, and erosion. Curiously, we find no significant trends in annual mean flow in the Alaskan Coastal Current (ACC), although note that these data are only available 2002-2015. Record-length trends in annually integrated heat and freshwater fluxes (primarily driven by volume flux trends) are large (0.06 ± 0.05 × 1020 J/yr; 30 ± 20 km3/yr; relative to -1.9 °C and 34.8 psu), with heat flux lows in 2001 and 2012 (∼3 × 1020 J) and highs in 2007 and 2015 (∼5.5 × 1020 J), and a freshwater range of ∼2300 km3 (2001) to ∼3500 km3 (2014). High-flow year 2015 (volume transport ∼1.1 Sv) has the highest annual mean temperature recorded, ∼0.7 °C, astoundingly warmer than the record-length mean of 0.0 ± 0.2 °C, while low-flow year 2012 (∼0.8 Sv) is also remarkably cold (∼-0.6 °C), likely due to anomalously weak northward flow in January-March, partly driven by anomalously strong southward winds in March. A seasonal decomposition of properties of the main flow shows significant freshening in winter (∼0.03 psu/yr, January-March) likely due to sea-ice changes, but no trend (or perhaps salinization) in the rest of the year. A seasonal warming trend in the strait proper in May and June (∼0.04 °C/yr) is reflected in a trend to earlier arrival (0.9 ± 0.8 days/yr) of waters warmer than 0 °C. Contrastingly, no significant trend is found in the time of cooling of the strait. The strait's seasonal increasing transport trends (∼0.02 Sv/yr) are largest from May-November, likely due to the large wind-driven variability masking the signal in other months. We show that Ekman set-up of waters along the coast in the strait can explain the strong correlation of the water velocity with along-strait winds (as opposed to across-strait winds). We highlight the strong seasonality of this relationship (r ∼ 0.8 in winter, but only ∼0.4 in summer), which reflects the weak influence of the (seasonally weak) winds in summer. By separating the flow into portions driven by (a) the local wind and (b) a far-field (Pacific-Arctic "pressure-head") forcing, we find the increase in the Bering Strait throughflow is primarily due to a strong increase in the far-field forcing, not changes in the wind. We propose a higher annual mean transport for the strait for the 2000s, (1.0 ± 0.05 Sv) based on recent flow increases, and present estimated seasonal climatologies for properties and fluxes for the strait and for the ACC. Heat and freshwater seasonalities are strongly influenced by the ACC and stratification. Finally we conclude that year-round in situ mooring are still the only currently viable way of obtaining accurate quantifications of the properties of the Pacific input to the Arctic.

32 CFR 245.6 - Abbreviations and acronyms.

Code of Federal Regulations, 2011 CFR

2011-07-01

...—Domestic Event Network DHS—Department of Homeland Security DND—Department of National Defence (Canada) DoD... (NORAD) NORAD—North American Aerospace Defense Command PACAF—Pacific Air Forces SCA—Security Control Authorization SEADS—Southeast Air Defense Sector (NORAD) SUA—Special Use Airspace TSA—Transportation Security...

32 CFR 245.6 - Abbreviations and acronyms.

Code of Federal Regulations, 2012 CFR

2012-07-01

...—Domestic Event Network DHS—Department of Homeland Security DND—Department of National Defence (Canada) DoD... (NORAD) NORAD—North American Aerospace Defense Command PACAF—Pacific Air Forces SCA—Security Control Authorization SEADS—Southeast Air Defense Sector (NORAD) SUA—Special Use Airspace TSA—Transportation Security...

32 CFR 245.6 - Abbreviations and acronyms.

Code of Federal Regulations, 2014 CFR

2014-07-01

...—Domestic Event Network DHS—Department of Homeland Security DND—Department of National Defence (Canada) DoD... (NORAD) NORAD—North American Aerospace Defense Command PACAF—Pacific Air Forces SCA—Security Control Authorization SEADS—Southeast Air Defense Sector (NORAD) SUA—Special Use Airspace TSA—Transportation Security...

32 CFR 245.6 - Abbreviations and acronyms.

Code of Federal Regulations, 2013 CFR

2013-07-01

...—Domestic Event Network DHS—Department of Homeland Security DND—Department of National Defence (Canada) DoD... (NORAD) NORAD—North American Aerospace Defense Command PACAF—Pacific Air Forces SCA—Security Control Authorization SEADS—Southeast Air Defense Sector (NORAD) SUA—Special Use Airspace TSA—Transportation Security...

Storm-driven Mixing and Potential Impact on the Arctic Ocean

NASA Technical Reports Server (NTRS)

Yang, Jiayan; Comiso, Josefino; Walsh, David; Krishfield, Richard; Honjo, Susumu; Koblinsky, Chester J. (Technical Monitor)

2001-01-01

Observations of the ocean, atmosphere, and ice made by Ice-Ocean Environmental Buoys (IOEBs) indicate that mixing events reaching the depth of the halocline have occurred in various regions in the Arctic Ocean. Our analysis suggests that these mixing events were mechanically forced by intense storms moving across the buoy sites. In this study, we analyzed these mixing events in the context of storm developments that occurred in the Beaufort Sea and in the general area just north of Fram Strait, two areas with quite different hydrographic structures. The Beaufort Sea is strongly influenced by inflow of Pacific water through Bering Strait, while the area north of Fram Strait is directly affected by the inflow of warm and salty North Atlantic water. Our analyses of the basin-wide evolution of the surface pressure and geostrophic wind fields indicate that the characteristics of the storms could be very different. The buoy-observed mixing occurred only in the spring and winter seasons when the stratification was relatively weak. This indicates the importance of stratification, although the mixing itself was mechanically driven. We also analyze the distribution of storms, both the long-term climatology as well as the patterns for each year in the last two decades. The frequency of storms is also shown to be correlated- (but not strongly) to Arctic Oscillation indices. This study indicates that the formation of new ice that leads to brine rejection is unlikely the mechanism that results in the type of mixing that could overturn the halocline. On the other hand, synoptic-scale storms can force mixing deep enough to the halocline and thermocline layer. Despite a very stable stratification associated with the Arctic halocline, the warm subsurface thermocline water is not always insulated from the mixed layer.

Wind-dependent beluga whale dive behavior in Barrow Canyon, Alaska

NASA Astrophysics Data System (ADS)

Stafford, K. M.; Citta, J. J.; Okkonen, S. R.; Suydam, R. S.

2016-12-01

Beluga whales (Delphinapterus leucas) are the most abundant cetacean in the Arctic. The Barrow Canyon region, Alaska, is a hotspot for Pacific Arctic belugas, likely because the oceanographic environment provides reliable foraging opportunities. Fronts are known to promote the concentration of planktonic prey; when Barrow-area winds are weak or from the west, a front associated with the Alaskan Coastal Current (ACC) intensifies. This front is weakened or disrupted when strong easterly winds slow or displace the ACC. To determine if winds influence the diving depth of belugas, we used generalized linear mixed models (GLMM) to examine how the dive behavior of animals instrumented with satellite-linked time-depth recorders varied with wind conditions. When projected along-canyon winds are from the WSW and the front associated with the ACC is enhanced, belugas tend to target shallower depths (10-100 m) associated with the front. In contrast, when strong winds from the ENE displaced the ACC, belugas tended to spend more time at depths >200 m where the Arctic halocline grades into relatively warmer Atlantic Water (AW). The probability of diving to >200 m, the number of dives >200 m, and the amount of time spent below 200 m were all significantly related to along-canyon wind stress (p<0.01). From these results and known relationships between wind stress, currents and frontal structure in Barrow Canyon and the characteristic vertical distribution of Arctic cod, we infer that the probability of belugas targeting different depth regimes is based upon how wind stress affects the relative foraging opportunities between these depth regimes. Belugas are known to target AW throughout the Beaufort Sea; however, this is the first work to show that the probability of targeting the AW layer is related to wind stress.

Intraspecific evolutionary relationships among peregrine falcons in western North American high latitudes

PubMed Central

Sage, George K.; Sonsthagen, Sarah A.; Gravley, Meg C.; Swem, Ted; Williams, Jeffrey C.; Longmire, Jonathan L.; Ambrose, Skip; Flamme, Melanie J.; Lewis, Stephen B.; Phillips, Laura; Anderson, Clifford; White, Clayton M.

2017-01-01

Subspecies relationships within the peregrine falcon (Falco peregrinus) have been long debated because of the polytypic nature of melanin-based plumage characteristics used in subspecies designations and potential differentiation of local subpopulations due to philopatry. In North America, understanding the evolutionary relationships among subspecies may have been further complicated by the introduction of captive bred peregrines originating from non-native stock, as part of recovery efforts associated with mid 20th century population declines resulting from organochloride pollution. Alaska hosts all three nominal subspecies of North American peregrine falcons–F. p. tundrius, anatum, and pealei–for which distributions in Alaska are broadly associated with nesting locales within Arctic, boreal, and south coastal maritime habitats, respectively. Unlike elsewhere, populations of peregrine falcon in Alaska were not augmented by captive-bred birds during the late 20th century recovery efforts. Population genetic differentiation analyses of peregrine populations in Alaska, based on sequence data from the mitochondrial DNA control region and fragment data from microsatellite loci, failed to uncover genetic distinction between populations of peregrines occupying Arctic and boreal Alaskan locales. However, the maritime subspecies, pealei, was genetically differentiated from Arctic and boreal populations, and substructured into eastern and western populations. Levels of interpopulational gene flow between anatum and tundrius were generally higher than between pealei and either anatum or tundrius. Estimates based on both marker types revealed gene flow between augmented Canadian populations and unaugmented Alaskan populations. While we make no attempt at formal taxonomic revision, our data suggest that peregrine falcons occupying habitats in Alaska and the North Pacific coast of North America belong to two distinct regional groupings–a coastal grouping (pealei) and a boreal/Arctic grouping (currently anatum and tundrius)–each comprised of discrete populations that are variously intra-regionally connected. PMID:29149202

The Effects of Spectral Nudging on Arctic Temperature and Precipitation Extremes as Produced by the Pan-Arctic WRF

NASA Astrophysics Data System (ADS)

Glisan, J. M.; Gutowski, W. J.; Higgins, M.; Cassano, J. J.

2011-12-01

Pan-Arctic WRF (PAW) simulations produced using the 50-km wr50a domain developed for the fully-coupled Regional Arctic Climate Model (RACM) were found to produce deep atmospheric circulation biases over the northern Pacific Ocean, manifested in pressure, geopotential height, and temperature fields. Various remedies were unsuccessfully tested to correct these large biases, such as modifying the physical domain or using different initial/boundary conditions. Spectral (interior) nudging was introduced as a way of constraining the model to be more consistent with observed behavior. However, such control over numerical model behavior raises concerns over how much nudging may affect unforced variability and extremes. Strong nudging may reduce or filter out extreme events, since the nudging pushes the model toward a relatively smooth, large-scale state. The question then becomes - what is the minimum spectral nudging needed to correct the biases occurring on the RACM domain while not limiting PAW simulation of extreme events? To determine this, case studies were devised, using a six-member PAW ensemble on the RACM grid with varying spectral nudging strength. Two simulations were run, one in the cold season (January 2007) and one in a warm season (July 2007). Precipitation and 2-m temperature fields were extracted from the output and analyzed to determine how changing spectral nudging strength impacts both temporal and spatial temperature and precipitation extremes. The maximum and minimum temperatures at each point from among the ensemble members were examined, on the 95th confidence interval. The maximum and minimums over the simulation period will also be considered. Results suggest that there is a marked lack of sensitivity to the degrees of nudging. Moreover, it appears nudging strength can be considerably smaller than the standard strength and still produce reliably good simulations.

Empirical algorithms to estimate water column pH in the Southern Ocean

NASA Astrophysics Data System (ADS)

Williams, N. L.; Juranek, L. W.; Johnson, K. S.; Feely, R. A.; Riser, S. C.; Talley, L. D.; Russell, J. L.; Sarmiento, J. L.; Wanninkhof, R.

2016-04-01

Empirical algorithms are developed using high-quality GO-SHIP hydrographic measurements of commonly measured parameters (temperature, salinity, pressure, nitrate, and oxygen) that estimate pH in the Pacific sector of the Southern Ocean. The coefficients of determination, R2, are 0.98 for pH from nitrate (pHN) and 0.97 for pH from oxygen (pHOx) with RMS errors of 0.010 and 0.008, respectively. These algorithms are applied to Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) biogeochemical profiling floats, which include novel sensors (pH, nitrate, oxygen, fluorescence, and backscatter). These algorithms are used to estimate pH on floats with no pH sensors and to validate and adjust pH sensor data from floats with pH sensors. The adjusted float data provide, for the first time, seasonal cycles in surface pH on weekly resolution that range from 0.05 to 0.08 on weekly resolution for the Pacific sector of the Southern Ocean.

Nightside High Latitude Magnetic Impulse Events

NASA Astrophysics Data System (ADS)

Engebretson, M. J.; Connors, M. G.; Braun, D.; Posch, J. L.; Kaur, M.; Guillon, S.; Hartinger, M.; Kim, H.; Behlke, R.; Reiter, K.; Jackel, B. J.; Russell, C. T.

2017-12-01

High latitude Magnetic Impulse Events (MIEs), isolated pulses with periods 5-10 min, were first noted in ground-based magnetometer data near local noon, and are now understood to be signatures of transient pressure increases in the solar wind (sudden impulses - SIs) and/or in the ion foreshock (traveling convection vortex events - TCVs). However, solitary pulses with considerably larger amplitude (ΔB up to 1500 nT) have often been observed in the night sector at these same latitudes. These events are not directly associated with transient external pressure increases, and are often large enough to produce significant ground induced currents. Although many night sector MIEs occur in association with substorm signatures, others appear to be very isolated. We present here a survey of intense MIE events identified in magnetometer data from the AUTUMNX and MACCS arrays in eastern Arctic Canada at all local times between July 1, 2014 and June 30, 2017. We also show maps of horizontal and vertical perturbations and maximum dB/dt values, as well as sample magnetograms, for several example events using data from these and other arrays in Arctic Canada, as well as in West Greenland and Antarctica, the latter to show the conjugate nature of these events. A basic relation to GIC data in the Hydro-Québec electrical transmission network in eastern Canada has been determined and will be discussed.

Long-term Internal Variability of the Tropical Pacific Atmosphere-Ocean System

NASA Astrophysics Data System (ADS)

Hadi Bordbar, Mohammad; Martin, Thomas; Park, Wonsun; Latif, Mojib

2016-04-01

The tropical Pacific has featured some remarkable trends during the recent decades such as an unprecedented strengthening of the Trade Winds, a strong cooling of sea surface temperatures (SST) in the eastern and central part, thereby slowing global warming and strengthening the zonal SST gradient, and highly asymmetric sea level trends with an accelerated rise relative to the global average in the western and a drop in the eastern part. These trends have been linked to an anomalously strong Pacific Walker Circulation, the major zonal atmospheric overturning cell in the tropical Pacific sector, but the origin of the strengthening is controversial. Here we address the question as to whether the recent decadal trends in the tropical Pacific atmosphere-ocean system are within the range of internal variability, as simulated in long unforced integrations of global climate models. We show that the recent trends are still within the range of long-term internal decadal variability. Further, such variability strengthens in response to enhanced greenhouse gas concentrations, which may further hinder detection of anthropogenic climate signals in that region.

The role of the Southern Hemisphere semiannual oscillation in the development of a precursor to central and eastern Pacific Southern Oscillation warm events

NASA Astrophysics Data System (ADS)

Meehl, Gerald A.; van Loon, Harry; Arblaster, Julie M.

2017-07-01

The semiannual oscillation (SAO) is a twice-yearly northward movement (in May-June-July (MJJ) and November-December-January (NDJ)) of the circumpolar trough of sea level pressure (SLP) in the Southern Hemisphere with effects throughout the troposphere. During MJJ the second harmonic of SLP, describing the SAO, has low values of SLP north of 50°S in the subtropical South Pacific, while the first harmonic, which is dominant over the Australian sector, increases to its peak. This once-a-year peak in negative SLP gradients (decreasing to the east) between Australia and the ocean to its east extends to the equatorial Pacific. Southern Oscillation warm events since 1950, with an intensification of this seasonal cycle, have larger-amplitude SST anomalies in the eastern equatorial Pacific in MJJ and during the following mature phase in NDJ. Weak amplification of the seasonal cycle in MJJ tends to be followed by larger-amplitude SST anomalies in the central equatorial Pacific during NDJ.

ICESCAPE Mission

NASA Image and Video Library

2010-07-03

Teams of scientists set up equipment on sea ice not far from the U.S. Coast Guard icebreaker Healy in the Chukchi Sea on July 4, 2010, where they spent the day collecting data. The research is part of NASA's ICESCAPE oceanographic mission to sample the physical, chemical and biological characteristics of the ocean and sea ice. Impacts of Climate change on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) is a multi-year NASA shipborne project. The bulk of the research will take place in the Beaufort and Chukchi Sea’s in summer of 2010 and fall of 2011. Photo Credit: (NASA/Kathryn Hansen)

Northwest passage: Trade route for large air cushion vehicles

NASA Technical Reports Server (NTRS)

Anderson, J. L.

1973-01-01

A conceptual vehicle and powerplant (10,000-ton) nuclear-powered air-cushion vehicle (ACV) that could open the Northwest Passage and other Arctic passages to commercial traffic is identified. The report contains a description of the conceptual vehicle, including the powerplant and operations, an assessment of technical feasibility, estimates of capital and operating costs, and identification of eligible cargo and markets. A comparison of the nuclear ACV freighter with nuclear container ships shows that for containerized or roll-on/roll-off cargo the ACV would provide greatly reduced transit time between North Atlantic and North Pacific ports at a competitive cost.

ICESCAPE Mission

NASA Image and Video Library

2010-07-03

Clark University's Karen Frey and Luke Trusel work amid sea ice in the Chukchi Sea on July 4, 2010, setting up an instrument that measures the optical properties of melt ponds. The research is part of NASA's ICESCAPE mission to sample the physical, chemical and biological characteristics of the ocean and sea ice. Impacts of Climate change on the Eco-Systems and Chemistry of the Arctic Pacific Environment (ICESCAPE) is a multi-year NASA shipborne project. The bulk of the research will take place in the Beaufort and Chukchi Sea’s in summer of 2010 and fall of 2011. Photo Credit: (NASA/Kathryn Hansen)

Radiative Forcing Due to Major Aerosol Emitting Sectors in China and India

NASA Technical Reports Server (NTRS)

Streets, David G.; Shindell, Drew Todd; Lu, Zifeng; Faluvegi, Greg

2013-01-01

Understanding the radiative forcing caused by anthropogenic aerosol sources is essential for making effective emission control decisions to mitigate climate change. We examined the net direct plus indirect radiative forcing caused by carbonaceous aerosol and sulfur emissions in key sectors of China and India using the GISS-E2 chemistry-climate model. Diesel trucks and buses (67 mW/ sq. m) and residential biofuel combustion (52 mW/ sq. m) in India have the largest global mean, annual average forcings due mainly to the direct and indirect effects of BC. Emissions from these two sectors in China have near-zero net global forcings. Coal-fired power plants in both countries exert a negative forcing of about -30 mW/ sq. m from production of sulfate. Aerosol forcings are largest locally, with direct forcings due to residential biofuel combustion of 580 mW/ sq. m over India and 416 mW/ sq. m over China, but they extend as far as North America, Europe, and the Arctic

The Trans-Pacific Partnership Agreement

DTIC Science & Technology

2010-06-25

New Zealand may focus on agricultural goods such as beef and dairy products. The possible inclusion of Vietnam may prove controversial from the...sensitive U.S. agriculture sectors such as beef , lamb, and dairy products. U.S. goods trade with New Zealand is relatively small. New Zealand was...10 Dairy

Publisher Correction: Response of Pacific-sector Antarctic ice shelves to the El Niño/Southern Oscillation

NASA Astrophysics Data System (ADS)

Paolo, F. S.; Padman, L.; Fricker, H. A.; Adusumilli, S.; Howard, S.; Siegfried, M. R.

2018-03-01

In the version of this Article originally published, there was a spelling mistake in Figure 3 where `La Niña' was incorrectly spelled `La Niño'. This has been corrected in all versions of the Article.

50 CFR Table 28c to Part 679 - Allocation of Rockfish Secondary Species

Code of Federal Regulations, 2013 CFR

2013-10-01

... ZONE OFF ALASKA Pt. 679, Table 28c Table 28c to Part 679—Allocation of Rockfish Secondary Species For... sector . . . Pacific cod 3.81% N/A Sablefish 6.78% 3.51% Rougheye rockfish N/A 58.87% Shortraker rockfish...

The nature of colored dissolved organic matter in the southern Canada Basin and East Siberian Sea

NASA Astrophysics Data System (ADS)

Guéguen, C.; McLaughlin, F. A.; Carmack, E. C.; Itoh, M.; Narita, H.; Nishino, S.

2012-12-01

Distributions of colored dissolved organic matter (CDOM) in the upper 400 m of the southern Canada Basin and East Siberian Sea were determined using an in situ WETStar fluorometer and fluorescence spectroscopy during cruises in 2008 as part of the Canada/US Joint Ocean Ice Study and Japan's International Polar Year program. Despite the low CDOM range (0.009-0.069 r.u.) observed in the upper 400 m of the study area, our results show that CDOM can be quantified from in situ DOM fluorescence sensor measurements. Unlike DOC concentrations, which are known to decrease with increasing depth, a pronounced mid-depth CDOM maximum was associated with the Pacific-derived winter water throughout our study area. Using parallel factor analysis (PARAFAC) to resolve dominant fluorophore components in fluorescence excitation-emission matrices (EEM), we identified three humic-like and two proteinaceous components. The nature and origin of these five fluorophores were investigated based on their fluorescent characteristics as well as their vertical and geographical distributions. The lowest terrestrial humic-like signals in the surface waters were mostly due to photochemical processes, whereas the highest microbial/marine humic-like signal revealed interactions with sediment during the formation of Pacific-origin haloclines over the Arctic shelves. The humic-like fluorophores dominated DOM fluorescence in the Westernmost region in the East Siberian Sea whereas the contribution of protein-like fluorophores was predominant elsewhere. The significant difference in CDOM composition between East and West of the 180° meridian suggests the presence of a front that divides our study area into the Eastern Chukchi—Beaufort and East Siberian sides. This indicates a change in water circulation, and that more than one DOM source affects our study area. Unlike proteinaceous material, the humic-like compounds varied significantly in the halocline. Ten to 20 percent enrichment was observed in terrestrially-derived DOM in the two Pacific-derived haloclines relative to the Atlantic-derived lower halocline. The application of PARAFAC modeling on fluorescent DOM is shown to be an important tool to investigate the dynamics and transport of allochthonous DOM in the Arctic Ocean.

Upper Ocean Evolution Across the Beaufort Sea Marginal Ice Zone

NASA Astrophysics Data System (ADS)

Lee, C.; Rainville, L.; Gobat, J. I.; Perry, M. J.; Freitag, L. E.; Webster, S.

2016-12-01

The observed reduction of Arctic summertime sea ice extent and expansion of the marginal ice zone (MIZ) have profound impacts on the balance of processes controlling sea ice evolution, including the introduction of several positive feedback mechanisms that may act to accelerate melting. Examples of such feedbacks include increased upper ocean warming though absorption of solar radiation, elevated internal wave energy and mixing that may entrain heat stored in subsurface watermasses (e.g., the relatively warm Pacific Summer and Atlantic waters), and elevated surface wave energy that acts to deform and fracture sea ice. Spatial and temporal variability in ice properties and open water fraction impact these processes. To investigate how upper ocean structure varies with changing ice cover, how the balance of processes shift as a function of ice fraction and distance from open water, and how these processes impact sea ice evolution, a network of autonomous platforms sampled the atmosphere-ice-ocean system in the Beaufort, beginning in spring, well before the start of melt, and ending with the autumn freeze-up. Four long-endurance autonomous Seagliders occupied sections that extended from open water, through the marginal ice zone, deep into the pack during summer 2014 in the Beaufort Sea. Gliders penetrated up to 200 km into the ice pack, under complete ice cover for up to 10 consecutive days. Sections reveal strong fronts where cold, ice-covered waters meet waters that have been exposed to solar warming, and O(10 km) scale eddies near the ice edge. In the pack, Pacific Summer Water and a deep chlorophyll maximum form distinct layers at roughly 60 m and 80 m, respectively, which become increasingly diffuse late in the season as they progress through the MIZ and into open water. Stratification just above the Pacific Summer Water rapidly weakens near the ice edge and temperature variance increases, likely due to mixing or energetic vertical exchange associated with strong lateral gradients at the MIZ. This presentation will discuss the evolution of the Arctic upper ocean over the summer to the start of freeze up and the relationship of its variability to sea ice extent and atmospheric forcing.

Blood selenium concentrations in female Pacific black brant molting in Arctic Alaska: Relationships with age and habitat salinity.

PubMed

Franson, J Christian; Flint, Paul L; Schmutz, Joel A

2016-10-15

Blood samples collected from 81 female Pacific black brant (Branta bernicla nigricans) molting near Teshekpuk Lake, Alaska, were analyzed for selenium concentration. The concentration of selenium in blood of after second year (hatched two or more years ago) females (0.84μg/g wet weight) was significantly greater than the concentration in second year (hatched the previous year) females (0.61μg/g wet weight). The concentrations of selenium we found in blood of black brant were 1.5 to 2 times greater than baseline values typical of freshwater birds, but considerably lower than reported in other marine waterfowl sampled in Alaska. This finding may be attributable in part to the nearly exclusive herbivorous diet of black brant. No relationship was noted between blood selenium concentration and molting habitat salinity. We are unaware of any previous reports of blood selenium concentrations in black brant. Published by Elsevier Ltd.

Genesis, Pathways, and Terminations of Intense Global Water Vapor Transport in Association with Large-Scale Climate Patterns

NASA Astrophysics Data System (ADS)

Sellars, S. L.; Kawzenuk, B.; Nguyen, P.; Ralph, F. M.; Sorooshian, S.

2017-12-01

The CONNected objECT (CONNECT) algorithm is applied to global Integrated Water Vapor Transport data from the NASA's Modern-Era Retrospective Analysis for Research and Applications - Version 2 reanalysis product for the period of 1980 to 2016. The algorithm generates life-cycle records in time and space evolving strong vapor transport events. We show five regions, located in the midlatitudes, where events typically exist (off the coast of the southeast United States, eastern China, eastern South America, off the southern tip of South Africa, and in the southeastern Pacific Ocean). Global statistics show distinct genesis and termination regions and global seasonal peak frequency during Northern Hemisphere late fall/winter and Southern Hemisphere winter. In addition, the event frequency and geographical location are shown to be modulated by the Arctic Oscillation, Pacific North American Pattern, and the quasi-biennial oscillation. Moreover, a positive linear trend in the annual number of objects is reported, increasing by 3.58 objects year-over-year.

A variant of the anomaly initialisation approach for global climate forecast models

NASA Astrophysics Data System (ADS)

Volpi, Danila; Guemas, Virginie; Doblas-Reyes, Francisco; Hawkins, Ed; Nichols, Nancy; Carrassi, Alberto

2014-05-01

This work presents a refined method of anomaly initialisation (AI) applied to the ocean and sea ice components of the global climate forecast model EC-Earth, with the following particularities: - the use of a weight to the anomalies, in order to avoid the risk of introducing too big anomalies recorded in the observed state, whose amplitude does not fit the range of the internal variability generated by the model. - the AI of the temperature and density ocean state variables instead of the temperature and salinity. Results show that the use of such refinements improve the skill over the Arctic region, part of the North and South Atlantic, part of the North and South Pacific and the Mediterranean Sea. In the Tropical Pacific the full field initialised experiment performs better. This is probably due to a displacement of the observed anomalies caused by the use of the AI technique. Furthermore, preliminary results of an anomaly nudging experiment are discussed.

76 FR 44155 - Pacific Halibut Fisheries; Catch Sharing Plan for Guided Sport and Commercial Fisheries in Alaska

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-22

...NMFS proposes regulations that would implement a catch sharing plan for the guided sport and commercial fisheries for Pacific halibut in waters of International Pacific Halibut Commission (IPHC) Regulatory Areas 2C (Southeast Alaska) and 3A (Central Gulf of Alaska). If approved, this catch sharing plan will change the annual process of allocating halibut between the guided sport and commercial fisheries in Area 2C and Area 3A, establish allocations for each sector, and specify harvest restrictions for guided sport anglers that are intended to limit harvest to the annual guided sport fishery catch limit. In order to provide flexibility for individual commercial and guided sport fishery participants, the proposed catch sharing plan also will authorize annual transfers of commercial halibut quota to charter halibut permit holders for harvest in the guided sport fishery. This action is necessary to achieve the halibut fishery management goals of the North Pacific Fishery Management Council.

Poleward Tropical Moisture Transport and its Link to Four Sequential Extreme Weather Events over North America in October 2007

NASA Astrophysics Data System (ADS)

Bosart, L. F.; Cordeira, J. M.; Archambault, H. M.; Moore, B. J.

2014-12-01

A case of four sequentially linked extreme weather events (EWEs) during 22 - 31 October 2007 which included wildfires in southern California, cold surges in northern and eastern Mexico, widespread heavy rain in the eastern United Sates, and heavy rains in southern Mexico is presented. These EWEs were preceded by a rapid dynamically driven rapid amplification of the upper-level flow across the North Pacific and North America associated with the formation of a large-amplitude Rossby wave train (RWT) through downstream baroclinic development involving multiple tropical and polar disturbance interactions with the North Pacific jet stream. The primary contributors to the formation of the large-amplitude RWT were two sequential upper-level polar disturbances, a diabatic Rossby vortex, western North Pacific TC Kajiki, and migratory extratropical cyclones (ECs). Deep subtropical and tropical moisture plumes resembling "atmospheric rivers" drawn poleward along warm conveyor belts into the warm sectors of these ECs played a critical role in further amplifying the downstream upper-level ridges based on an Eulerian analysis of negative potential vorticity advection by the irrotational wind and a Lagrangian trajectory analysis of tropical and subtropical moisture sources. In particular, these atmospheric rivers extending poleward from TC Kajiki and from the subtropical eastern North Pacific into the warm sectors of polar disturbance-generated ECs over the western and eastern North Pacific, respectively, bolstered latent heat release and ridge building and contributed to additional upper-level flow amplification. The EWEs occurred subsequent to anticyclonic wave breaking over western North America and the concomitant downstream formation of a meridionally elongated potential vorticity streamer over the central United States. The resulting high-amplitude flow pattern over North America favored the formation of the aforementioned EWEs by promoting an extensive meridional exchange of air masses from high and low latitudes.

Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Northwest): Pink salmon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonar, S.A.; Pauley, G.B.; Thomas, G.L.

1989-01-01

Species profiles are literature summaries of the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species. They are designed to assist in environmental impact assessment. The pink salmon, often called humpback salmon or humpy, is easily identified by its extremely small scales (150 to 205) on the lateral line. They are the most abundant of the Pacific salmon species and spawn in North American and Asian streams bordering the Pacific and Arctic Oceans. They have a very simple two-year life cycle, which is so invariable that fish running in odd-numbered years are isolated from fish running inmore » even-numbered years so that no gene flow occurs between them. Adults spawn in the fall and the young fry emerge in the spring. The pink salmon is less desirable in commercial and sport catches than most other salmon because of its small size and its soft pale flesh. The Puget Sound region of Washington State is the southern geographic limit of streams supporting major pink salmon runs in the eastern North Pacific. Pink salmon runs are presently only in odd-numbered years in this region. Optimum water temperatures for spawning range from 7.2 to 12.8/degree/C. Productive pink salmon streams have less than 5.0% by volume of fine sediments (less than or equal to0.8 mm). 87 refs., 5 figs., 1 tab.« less

75 FR 4684 - Fisheries off West Coast States; Pacific Coast Groundfish Fishery; Data Collection for the Trawl...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-29

... Coast groundfish fishery. The trawl rationalization program is intended to increase net economic benefits, create individual economic stability, provide full utilization of the trawl sector allocation... one time reporting will have a significant economic impact on small entities, as the estimated...

Developing a Qualifications Structure for the Finance Services Industry in Malaysia and Beyond

ERIC Educational Resources Information Center

Manshor, Amat Taap; Chong, Siong Choy; Cameron, Roslyn

2014-01-01

The development of qualifications systems and frameworks assists in promoting lifelong learning and work-based recognition systems. Several nations in the Asian Pacific region have established national qualifications frameworks across their respective educational sectors (e.g., Australia, New Zealand, Hong Kong, Malaysia and the Philippines),…

The Trans-Pacific Partnership Agreement

DTIC Science & Technology

2010-04-14

New Zealand may focus on agricultural goods such as beef and dairy products. The possible inclusion of Vietnam may prove controversial from the...on sensitive U.S. agriculture sectors such as beef , lamb, and dairy products. U.S. goods trade with New Zealand is relatively small. New Zealand was...10 Dairy

Vocational Qualification Frameworks in Asia-Pacific: A Cresting Wave of Educational Reform?

ERIC Educational Resources Information Center

Comyn, Paul

2009-01-01

The introduction of national qualification frameworks (NQFs), including frameworks specifically for the vocational sector (NVQFs), are policy initiatives that have far reaching implications for the management and delivery of education and training. Despite the caution called for by researchers and the challenging reality of implementation in both…

75 FR 3981 - National Angel Island Day, 2010

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-26

..., villages, and farms of their birth, they journeyed across the Pacific, seeking better lives for themselves... contributed immeasurably to our Nation as leaders in every sector of American life. The children of Angel... things are possible in America, this vibrant community has created a beacon of hope for future...

76 FR 79153 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-21

... halibut sport fishery in International Pacific Halibut Commission Areas 2C (Southeast Alaska) and 3A... between the guided sport (i.e., the charter sector) and the commercial halibut fishery. To assess the... voluntary survey efforts. In order to address this information gap, NMFS' Alaska Fisheries Science Center...

Balance within the Rebalance: The Supporting Role of the U.S. Military in the Asia-Pacific Region

DTIC Science & Technology

2014-06-01

issues such as migration, corruption, drug trafficking , human trafficking , and other transnational crime, threaten the stability and prosperity within...infrastructure investment, public sector partnerships, and the upgrading of human capital.5 This global factory has resulted in unprecedented and economic...

Training in Industrial Technology: A Collection of Essays.

ERIC Educational Resources Information Center

Hatton, Michael J., Ed.

Prepared as part of the Asia Pacific Economic Cooperation Forum's efforts to explore issues related to economic development and technology training, the three essays in this collection describe industrial training efforts at community colleges, focusing on partnerships with the private sector, programs targeted at women, and the use of…

Guam '79: Facing the New Pacific Era. Annual Economic Review.

ERIC Educational Resources Information Center

Guam Dept. of Commerce, Agana.

Socioeconomic conditions and developments are analysed in this report, designed to be useful to planners in government and the private sector. The introduction summarizes Guam's economic outlook emphasizing the effect of federal funds for reconstruction following Supertyphoon Pamela in 1976, moderate growth in tourism, and Guam's potential to…

Arctic Climate during Eocene Hyperthermals: Wet Summers on Ellesmere Island?

NASA Astrophysics Data System (ADS)

Greenwood, D. R.; West, C. K.; Basinger, J. F.

2012-12-01

Previous work has shown that during the late Paleocene to middle Eocene, mesothermal conditions (i.e., MAT ~12-15° C) and high precipitation (MAP > 150cm/yr) characterized Arctic climates - an Arctic rain forest. Recent analyses of Arctic Eocene wood stable isotope chemistry are consistent with the annual and seasonal temperature estimates from leaf physiognomy and nearest living relative analogy from fossil plants, including the lack of freezing winters, but is interpreted as showing that there was a summer peak in precipitation - modern analogs are best sought on the summer-wet east coasts (e.g., China, Japan, South Korea) not the winter-wet west coasts of present-day northern temperate continents (e.g., Pacific northwest of North America). Highly seasonal 'monsoon-type' summer-wet precipitation regimes (i.e., summer precip./winter precip. > 3.0) seem to characterize Eocene hyperthermal conditions in several regions of the earth, including the Arctic and Antarctic, based on both climate model sensitivity experiments and the paleoclimate proxy evidence. The leaf physiognomy proxy previously applied to estimate Arctic Paleogene precipitation was leaf area analysis (LAA), a correlation between mean leaf size in woody dicot vegetation and annual precipitation. New data from modern monsoonal sites, however demonstrates that for deciduous-dicot dominated vegetation, summer precipitation determines mean leaf size, not annual totals, and therefore that under markedly seasonal precipitation and/or light regimes that summer precipitation is being estimated using LAA. Presented here is a new analysis of a leaf macrofloras from 3 separate florules of the Margaret Formation (Split Lake, Stenkul Fiord and Strathcona Fiord) from Ellesmere Island that are placed stratigraphically as early Eocene, and likely fall within Eocene thermal maximum 1 (ETM1; = the 'PETM') or ETM2. These floras are each characterized by a mix of large-leafed and small-leafed dicot taxa, with overall mean leaf size across all leaf morphotypes comparable to that previously reported for late Paleocene to middle Eocene floras from Ellesmere and Axel Heiberg islands of Nunavut. Applying the conventional leaf area analysis to the putatively ETM1 floras yielded estimates of mean annual precipitation 100-200cm/yr, consistent with the previous reports for the late Paleocene to middle Eocene. CLAMP analysis applied to these floras yields growing season precipitation comparable to the annual precipitation estimate from leaf area analysis. These data are interpreted as reflecting high summer precipitation in the Arctic during the late Paleocene to middle Eocene, including ETM1, as precipitation in the dark polar winter months will have had no effect on leaf size while the trees were dormant, corroborating the results from Eocene wood chemistry. High summer precipitation (i.e., light-season = wettest season) in the Eocene Arctic during hyperthermals would have contributed to regional warmth.

Ecological and Economic Prerequisites for the Extraction of Solid Minerals from the Bottom of the Arctic Seas

NASA Astrophysics Data System (ADS)

Myaskov, Alexander; Gonchar, Alexander

2017-11-01

The world ocean has huge reserves of minerals that are contained directly in the water, as well as on the surface of its bottom and in its subsoils. The deposits of solid minerals on the surface of the bottom of the World Ocean are considered the most promising for industrial extraction. The deposits of ferromanganese nodules, cobalt-manganese crusts and polymetallic sulphides are considered as an object of extracting more often than others. There are the largest deposits of ferromanganese nodules in the central and southern parts of the Pacific Ocean, in the central part of the Indian Ocean, and in the seas of the Arctic Ocean near Russia. The deposits of ferromanganese nodules are a serious alternative to deposits of manganese ore on land. However, there are many factors influencing the efficiency of the development of ferromanganese deposits, the most significant are: the content of the useful component in the ore, the depth of the bottom and the distance from the seaports. It is also necessary to take into account the possible environmental consequences of underwater mining.

Drivers of long-term precipitation and runoff variability in the southeastern USA

NASA Astrophysics Data System (ADS)

Engström, Johanna; Waylen, Peter

2018-02-01

The hydroclimatology of the southeastern USA (AL, GA, NC, SC, and TN) is analyzed from a holistic perspective, including multiple climate drivers. Monthly precipitation modeled by the PRISM group and runoff data (1952-2011) from 18 basins are analyzed using a single-field based principal component's analysis. Results indicate that the Atlantic Multidecadal Oscillation and El Niño-Southern Oscillation are the main atmospheric drivers of hydroclimate variability in the region, sometimes operating at several months' lag. Their influence is the strongest in the fall through spring, which corresponds with the dry season in the southern parts of the study area thereby increasing pressure on already limited water resources. The Arctic Oscillation, North Atlantic Oscillation, and Pacific-North American patterns vary on shorter-term bases, and also show a significant, but temporally more sporadic influence. Insight is also brought to the ongoing discussion, confirming the disassociation of the Arctic and North Atlantic Oscillation. Findings can be used in water resources forecasting, giving an indication of expected water volumes several months ahead.

Species diversity in the marine microturbellarian Astrotorhynchus bifidus sensu lato (Platyhelminthes: Rhabdocoela) from the Northeast Pacific Ocean.

PubMed

Van Steenkiste, Niels W L; Herbert, Elizabeth R; Leander, Brian S

2018-03-01

Increasing evidence suggests that many widespread species of meiofauna are in fact regional complexes of (pseudo-)cryptic species. This knowledge has challenged the 'Everything is Everywhere' hypothesis and also partly explains the meiofauna paradox of widespread nominal species with limited dispersal abilities. Here, we investigated species diversity within the marine microturbellarian Astrotorhynchus bifidus sensu lato in the Northeast Pacific Ocean. We used a multiple-evidence approach combining multi-gene (18S, 28S, COI) phylogenetic analyses, several single-gene and multi-gene species delimitation methods, haplotype networks and conventional taxonomy to designate Primary Species Hypotheses (PSHs). This included the development of rhabdocoel-specific COI barcode primers, which also have the potential to aid in species identification and delimitation in other rhabdocoels. Secondary Species Hypotheses (SSHs) corresponding to morphospecies and pseudo-cryptic species were then proposed based on the minimum consensus of different PSHs. Our results showed that (a) there are at least five species in the A. bifidus complex in the Northeast Pacific Ocean, four of which can be diagnosed based on stylet morphology, (b) the A. bifidus complex is a mixture of sympatric and allopatric species with regional and/or subglobal distributions, (c) sympatry occurs on local (sample sites), regional (Northeastern Pacific) and subglobal (Northern Atlantic, Arctic, Northeastern Pacific) scales. Mechanisms for this co-occurrence are still poorly understood, but we hypothesize they could include habitat differentiation (spatial and/or seasonal) and life history characteristics such as sexual selection and dispersal abilities. Our results also suggest the need for improved sampling and exploration of molecular markers to accurately map gene flow and broaden our understanding of species diversity and distribution of microturbellarians in particular and meiofauna in general. Copyright © 2017 Elsevier Inc. All rights reserved.