Stable water isotope observations during INTAROS cruises North of Svalbard: links to atmospheric circulation and sea ice processes

2020 ◽  
Author(s):  
Alexandra Touzeau ◽  
Harald Sodemann ◽  
Hanne Sagen ◽  
Mats Anders Granskog ◽  
Bonnie Raffel ◽  
...  
Keyword(s):  
Sea Ice ◽  
High Latitude ◽  
Barents Sea ◽  
Water Cycle ◽  
Isotope Composition ◽  
Ice Cores ◽  
The South ◽  
Air Mass ◽  
The North ◽  
Water Isotope

<p>Water isotopes measured in ice cores are well-known tracers of paleoclimate variations. The ratio of heavy to light isotope in snow is indeed strongly controlled by the temperature during condensation along the entire airmass transport. This allows the utilization of isotope variability in the water cycle in current climatic conditions, and on weather time scales, to try to pinpoint key events and processes building up (or re-stating) the isotope signature of a given air mass. Because isotopic fractionation occurs every time water changes phase, it is highly beneficial to sample concurrently the different water reservoirs (i.e. seawater, sea ice, snow, rain and vapor) in order to truly understand the processes at work.</p><p>Here we present stable water isotope data from two cruises north of Svalbard within the INTAROS project (summer 2018 and summer 2019). During these cruises, vapor isotope composition was measured quasi-continuously on the coast guard icebreaker <em>KV Svalbard</em>. Seawater and precipitation samples were collected continuously throughout the cruises. The 2018 cruise mainly targeted locations within the Marginal Ice Zone north of Svalbard. On the 2019 cruise, sea ice samples and snow samples were collected at 8 ice stations, all the way to the North Pole. The liquid/solid samples were later analyzed at FARLAB at the University of Bergen.</p><p>A first analysis of the dataset shows that stable water isotope values vary with air mass origin, with marked differences between '<sup>18</sup>O-enriched’ air coming from the south-east (Barents Sea) and ‘<sup>18</sup>O-depleted’ air from the north-west (Inner Arctic) during the second cruise. During the 2019 cruise, vapor in air from the south-east tends to have relatively low d-excess values whereas precipitation is largely at equilibrium with the ambient vapor. This INTAROS dataset will be highly beneficial for studies using (coupled) isotope-enabled models, such as earth system models or high-latitude regional climate models, to validate their representation of the high-latitude water cycle.</p><p> </p>

scholarly journals How warm was the last interglacial? New model–data comparisons

2013 ◽  
Vol 371 (2001) ◽  
pp. 20130097 ◽  
Author(s):  
Bette L. Otto-Bliesner ◽  
Nan Rosenbloom ◽  
Emma J. Stone ◽  
Nicholas P. McKay ◽  
Daniel J. Lunt ◽  
...  
Keyword(s):  
Sea Ice ◽  
Surface Temperature ◽  
High Latitude ◽  
Ice Cores ◽  
Boreal Summer ◽  
Last Interglacial ◽  
Climate System Model ◽  
Surface Temperature Change ◽  
The North ◽  
Proxy Reconstructions

A Community Climate System Model, Version 3 (CCSM3) simulation for 125 ka during the Last Interglacial (LIG) is compared to two recent proxy reconstructions to evaluate surface temperature changes from modern times. The dominant forcing change from modern, the orbital forcing, modified the incoming solar insolation at the top of the atmosphere, resulting in large positive anomalies in boreal summer. Greenhouse gas concentrations are similar to those of the pre-industrial (PI) Holocene. CCSM3 simulates an enhanced seasonal cycle over the Northern Hemisphere continents with warming most developed during boreal summer. In addition, year-round warming over the North Atlantic is associated with a seasonal memory of sea ice retreat in CCSM3, which extends the effects of positive summer insolation anomalies on the high-latitude oceans to winter months. The simulated Arctic terrestrial annual warming, though, is much less than the observational evidence, suggesting either missing feedbacks in the simulation and/or interpretation of the proxies. Over Antarctica, CCSM3 cannot reproduce the large LIG warming recorded by the Antarctic ice cores, even with simulations designed to consider observed evidence of early LIG warmth in Southern Ocean and Antarctica records and the possible disintegration of the West Antarctic Ice Sheet. Comparisons with a HadCM3 simulation indicate that sea ice is important for understanding model polar responses. Overall, the models simulate little global annual surface temperature change, while the proxy reconstructions suggest a global annual warming at LIG (as compared to the PI Holocene) of approximately 1 ° C, though with possible spatial sampling biases. The CCSM3 SRES B1 (low scenario) future projections suggest high-latitude warmth similar to that reconstructed for the LIG may be exceeded before the end of this century.

Correlated Millennial-Scale Changes in Surface Hydrography and Terrigenous Sediment Yield Inferred from Last-Glacial Marine Deposits off Northeastern Brazil

1998 ◽  
Vol 50 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Helge W. Arz ◽  
Jürgen Pätzold ◽  
Gerold Wefer
Keyword(s):  
North Atlantic ◽  
Isotope Composition ◽  
Sediment Cores ◽  
Ice Cores ◽  
Northeastern Brazil ◽  
Salt Flux ◽  
Terrigenous Sediment ◽  
The North ◽  
North Brazil ◽  
The North Atlantic

The stable isotope composition of planktonic foraminifera correlates with evidence for pulses of terrigenous sediment in a sediment core from the upper continental slope off northeastern Brazil. Stable oxygen isotope records of the planktonic foraminiferal species Globigerinoides sacculiferand Globigerinoides ruber(pink) reveal sub-Milankovitch changes in sea-surface hydrography during the last 85,000 yr. Warming of the surface water coincided with terrigenous sedimentation pulses that are inferred from high XRF intensities of Ti and Fe, and which suggest humid conditions in northeast Brazil. These tropical signals correlate with climatic oscillations recorded in Greenland ice cores (Dansgaard-Oeschger cycles) and in sediment cores from the North Atlantic (Heinrich events). Trade winds may have caused changes in the North Brazil Current that altered heat and salt flux into the North Atlantic, thus affecting the growth and decay of the large glacial ice sheets.

North Atlantic jet stream projections in the context of the past 1,250 years

2021 ◽  
Vol 118 (38) ◽  
pp. e2104105118
Author(s):  
Matthew B. Osman ◽  
Sloan Coats ◽  
Sarah B. Das ◽  
Joseph R. McConnell ◽  
Nathan Chellman
Keyword(s):  
21St Century ◽  
North Atlantic ◽  
Climate Model ◽  
Ice Cores ◽  
Natural Variability ◽  
Jet Stream ◽  
Early 21St Century ◽  
The North ◽  
North Atlantic Jet ◽  
Water Isotope

Reconstruction of the North Atlantic jet stream (NAJ) presents a critical, albeit largely unconstrained, paleoclimatic target. Models suggest northward migration and changing variance of the NAJ under 21st-century warming scenarios, but assessing the significance of such projections is hindered by a lack of long-term observations. Here, we incorporate insights from an ensemble of last-millennium water isotope–enabled climate model simulations and a wide array of mean annual water isotope (δ18O) and annually accumulated snowfall records from Greenland ice cores to reconstruct North Atlantic zonal-mean zonal winds back to the 8th century CE. Using this reconstruction we provide preobservational constraints on both annual mean NAJ position and intensity to show that late 20th- and early 21st-century NAJ variations were likely not unique relative to natural variability. Rather, insights from our 1,250 year reconstruction highlight the overwhelming role of natural variability in thus far masking the response of midlatitude atmospheric dynamics to anthropogenic forcing, consistent with recent large-ensemble transient modeling experiments. This masking is not projected to persist under high greenhouse gas emissions scenarios, however, with model projected annual mean NAJ position emerging as distinct from the range of reconstructed natural variability by as early as 2060 CE.

scholarly journals The link between the Barents Sea and ENSO events simulated by NEMO model

Ocean Science ◽  
2012 ◽  
Vol 8 (6) ◽  
pp. 971-982 ◽  
Author(s):  
V. N. Stepanov ◽  
H. Zuo ◽  
K. Haines
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Barents Sea ◽  
Southern Oscillation ◽  
Similar Response ◽  
Enso Events ◽  
Ice Volume ◽  
The North ◽  
The Barents Sea ◽  
The North Atlantic

Abstract. An analysis of observational data in the Barents Sea along a meridian at 33°30' E between 70°30' and 72°30' N has reported a negative correlation between El Niño/La Niña Southern Oscillation (ENSO) events and water temperature in the top 200 m: the temperature drops about 0.5 °C during warm ENSO events while during cold ENSO events the top 200 m layer of the Barents Sea is warmer. Results from 1 and 1/4-degree global NEMO models show a similar response for the whole Barents Sea. During the strong warm ENSO event in 1997–1998 an anomalous anticyclonic atmospheric circulation over the Barents Sea enhances heat loses, as well as substantially influencing the Barents Sea inflow from the North Atlantic, via changes in ocean currents. Under normal conditions along the Scandinavian peninsula there is a warm current entering the Barents Sea from the North Atlantic, however after the 1997–1998 event this current is weakened. During 1997–1998 the model annual mean temperature in the Barents Sea is decreased by about 0.8 °C, also resulting in a higher sea ice volume. In contrast during the cold ENSO events in 1999–2000 and 2007–2008, the model shows a lower sea ice volume, and higher annual mean temperatures in the upper layer of the Barents Sea of about 0.7 °C. An analysis of model data shows that the strength of the Atlantic inflow in the Barents Sea is the main cause of heat content variability, and is forced by changing pressure and winds in the North Atlantic. However, surface heat-exchange with the atmosphere provides the means by which the Barents sea heat budget relaxes to normal in the subsequent year after the ENSO events.

scholarly journals Predictability of the Barents Sea Ice in Early Winter: Remote Effects of Oceanic and Atmospheric Thermal Conditions from the North Atlantic

2014 ◽  
Vol 27 (23) ◽  
pp. 8884-8901 ◽  
Author(s):  
Takuya Nakanowatari ◽  
Kazutoshi Sato ◽  
Jun Inoue
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Barents Sea ◽  
Temperature Anomaly ◽  
Early Winter ◽  
Subsurface Temperature ◽  
The North ◽  
The Barents Sea ◽  
Subsurface Temperature Anomaly ◽  
The North Atlantic

Abstract Predictability of sea ice concentrations (SICs) in the Barents Sea in early winter (November–December) is studied using canonical correlation analysis with atmospheric and ocean anomalies from the NCEP Climate Forecast System Reanalysis (CFSR) data. It is found that the highest prediction skill for a single-predictor model is obtained from the 13-month lead subsurface temperature at 200-m depth (T200) and the in-phase meridional surface wind (Vsfc). T200 skillfully predicts SIC variability in 35% of the Barents Sea, mainly in the eastern side. The T200 for negative sea ice anomalies exhibits warm anomalies in the subsurface ocean temperature downstream of the Norwegian Atlantic Slope Current (NwASC) on a decadal time scale. The diagnostic analysis of NCEP CFSR data suggests that the subsurface temperature anomaly stored below the thermocline during summer reemerges in late autumn by atmospheric cooling and affects the sea ice. The subsurface temperature anomaly of the NwASC is advected from the North Atlantic subpolar gyre over ~3 years. Also, Vsfc skillfully predicts SIC variability in 32% of the Barents Sea, mainly in the western side. The Vsfc for the negative sea ice anomalies exhibits southerly wind anomalies; Vsfc is related to the large-scale atmospheric circulation patterns from the subtropical North Atlantic to the Eurasian continent. This study suggests that both atmospheric and oceanic remote effects have a potential impact on the forecasting accuracy of SIC.

scholarly journals Spatial hydrochemical structure in surface waters of the Southern ocean between Africa and Antarctica

2021 ◽  
Vol 67 (4) ◽  
pp. 328-347
Author(s):  
K. V. Artamonova ◽  
I. A. Gangnus ◽  
L. A. Dukhova ◽  
V. V. Maslennikov ◽  
N. A. Lavinen
Keyword(s):  
Surface Layer ◽  
Southern Ocean ◽  
Interannual Variability ◽  
High Latitude ◽  
Polar Front ◽  
Hydrochemical Characteristics ◽  
The South ◽  
The North ◽  
The Antarctic ◽  
Subantarctic Front

Some hydrochemical characteristics and, first of all, the main nutrients (phosphorus, nitrogen, silicon) can be used as markers for distinguishing different types of water masses and positions of the main fronts of the Southern Ocean. The seasonal and interannual variability of these characteristics also reflects the character of biological processes in the surface layer of the ocean, which is important for assessing biological productivity. The aim of this study was to analyze the main features of the spatial distribution of hydrochemical characteristics in the surface layer in the Atlantic and Indian Ocean sectors of the Southern Ocean between the Subantarctic Front and the shores of Antarctica and assess their seasonal (spring–autumn) and interannual variability for the observation period from 2008 to 2020. We describe the surface nutrient concentrations between Africa and Antarctica along the transects that cross the Subantarctic Front (SAF) in the north, the Polar Frontal Zone (PFS), Polar Front (PF) and Antarctic Zone water in the south. The findings revealed an increase in dissolved oxygen and nutrients towards the south. Nitrates changed values within the SAF from 15 μM to 24 μM, whereas values from 1.2 μM to 1.7 μM were observed for phosphates. Silicate increased considerably within the Polar Front, from 6.6 μM to 20.8 μM. An analysis was carried out of the seasonal and interannual variability of the hydrochemical conditions in the surface layer of the Southern Ocean. The interannual variability of the nutrients was determined by the spatial variability of the main fronts of the Antarctic Circumpolar Current (ACC) and the intensity of the largescale Weddell Gyre (WG). Since 2017, there has been an increase in the meridional transfer of waters: in the Antarctic Summer 2017–2018, there was a spreading of high-nutrient WG waters toward the north, and in the Summer 2019–2020, the low-nutrient waters anomaly was transferred far to the south (up to 60°S).According to the data obtained, the seasonal dynamics of the nutrients in the surface layer of the Southern Ocean was rather weakly expressed. An exception is the high-latitude waters of the Cooperation and Davis Seas, where maximum seasonal variability of the hydrochemical characteristics was observed. The highest rate of nutrient consumption was observed in the coastal area of the Cooperation Sea near the fast ice edge from mid–December to early January and reached 3.2 μM per day for silicate, 1.8 μM per day for nitrates, and 0.12 μM per day for mineral phosphorus. The results of the long-term monitoring of the hydrochemical conditions in the Cooperation Sea made it possible to distinguish conditionally “warm” years with early vegetation (at the end of December) and intensive consumption of nutrients by phytoplankton, and “cold” years, when the formation of high-latitude “oases” in December–January was not observed.

scholarly journals A Cretaceous dinoflagellate cyst zonation for NE Greenland

2019 ◽  
Vol 157 (10) ◽  
pp. 1658-1692 ◽  
Author(s):  
H. Nøhr-Hansen ◽  
S. Piasecki ◽  
P. Alsen
Keyword(s):  
North Sea ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Barents Sea ◽  
The South ◽  
Norwegian Sea ◽  
Dinoflagellate Cyst ◽  
The North ◽  
Northern North Sea ◽  
First Time

AbstractA palynostratigraphic zonation is for the first time established for the entire Cretaceous succession in NE Greenland from Traill Ø in the south to Store Koldewey in the north (72–76.5° N). The zonation is based on samples from three cores and more than 100 outcrop sections. The zonation is calibrated to an updated ammonite zonation from the area and to palynozonations from the northern North Sea, Norwegian Sea and Barents Sea areas. The palynozonation is primarily based on dinoflagellate cyst and accessory pollen. The Cretaceous succession is divided into 15 palynozones: seven Lower Cretaceous zones and eight Upper Cretaceous zones. The two lowermost zones are new. The following five (Lower Cretaceous) zones have already been described. Two of the Upper Cretaceous zones are new. The zones have been subdivided into 20 subzones, 11 of which have been described previously and one of which has been revised/redefined. Nine subzones (Upper Cretaceous) are new. More than 100 stratigraphical events representing more than 70 stratigraphic levels have been recognized and presented in an event-stratigraphic scheme.

scholarly journals Stable Isotope Records from Mount Logan, Eclipse Ice Cores and Nearby Jellybean Lake. Water Cycle of the North Pacific Over 2000 Years and Over Five Vertical Kilometres: Sudden Shifts and Tropical Connections

2006 ◽  
Vol 58 (2-3) ◽  
pp. 337-352 ◽  
Author(s):  
D. A. Fisher ◽  
C. Wake ◽  
K. Kreutz ◽  
K. Yalcin ◽  
E. Steig ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Pacific Northwest ◽  
Water Cycle ◽  
Ice Cores ◽  
Zonal Flow ◽  
Ice Age ◽  
Lapse Rate ◽  
Wave System ◽  
Model Simulations ◽  
The North

Abstract Three ice cores recovered on or near Mount Logan, together with a nearby lake record (Jellybean Lake), cover variously 500 to 30 000 years. This suite of records offers a unique view of the lapse rate in stable isotopes from the lower to upper troposphere. The region is climatologically important, being beside the Cordilleran pinning-point of the Rossby Wave system and the Aleutian Low. Comparison of stable isotope series over the last 2000 years and model simulations suggest sudden and persistent shifts between modern (mixed) and zonal flow regimes of water vapour transport to the Pacific Northwest. The last such shift was in A.D. 1840. Model simulations for modern and “pure” zonal flow suggest that these shifts are consistent regime changes between these flow types, with predominantly zonal flow prior to ca. A.D. 1840 and modern thereafter. The 5.4 and 0.8 km asl records show a shift at A.D. 1840 and another at A.D. 800. It is speculated that the A.D. 1840 regime shift coincided with the end of the Little Ice Age and the A.D. 800 shift with the beginning of the European Medieval Warm Period. The shifts are very abrupt, taking only a few years at most.

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