Verification of a new NOAA/NSIDC passive microwave sea-ice concentration climate record

Walter N. Meier,

Ge Peng,

Donna J. Scott,

Matt H. Savoie

Опубликована Дек. 22, 2014

A new satellite-based passive microwave sea-ice concentration product developed for the National Oceanic and Atmospheric Administration (NOAA) Climate Data Record (CDR) programme is evaluated via comparison with other passive microwave-derived estimates. The new product leverages two well-established concentration algorithms, known as the NASA Team and Bootstrap, both developed at and produced by the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC). The sea-ice estimates compare well with similar GSFC products while also fulfilling all NOAA CDR initial operation capability (IOC) requirements, including (1) self-describing file format, (2) ISO 19115-2 compliant collection-level metadata, (3) Climate and Forecast (CF) …

Changes in meltwater chemistry over a 20-year period following a thermal regime switch from polythermal to cold-based glaciation at Austre Brøggerbreen, Svalbard

Aga Nowak,

Andy Hodson

Опубликована Окт. 23, 2014

Our long-term study gives a rare insight into meltwater hydrochemistry following the transition of Austre Brøggerbreen from polythermal to cold-based glaciation and its continued retreat. We find that the processes responsible for ion acquisition did not change throughout the period of records but became more productive. Two regimes before and after July/August 2000 were identified from changes in solute concentrations and pH. They resulted from increased chemical weathering occurring in ice-marginal and proglacial environments that have become progressively exposed by glacier retreat. Carbonate carbonation nearly doubled between 2000 and 2010, whilst increases in the weathering of silicate minerals were also …

Alien invasions in Antarctica—is anyone liable?

Kevin A. Hughes,

Peter Convey

Опубликована Май 12, 2014

The introduction of non-native species to Antarctica in association with human activities is a major threat to indigenous biodiversity and the region's unique ecosystems, as has been well-demonstrated in other ecosystems globally. Existing legislation contained in the Protocol on Environmental Protection to the Antarctic Treaty does not specifically make the eradication of non-native species mandatory, although it is implicit that human-assisted introductions should not take place. Furthermore, to date, eradications of non-native species in the Treaty area have been infrequent and slow to progress. In 2005 an additional Annex (VI) to the Protocol was agreed concerning “Liability arising from environmental …

Atmospheric trace elements in aerosols observed over the Southern Ocean and coastal East Antarctica

Guojie Xu,

Yuan Gao

Опубликована Ноя. 17, 2014

Atmospheric aerosol samples were collected over the Southern Ocean (SO) and coastal East Antarctica (CEA) during the austral summer of 2010/11. Samples were analysed for trace elements, including Na, Mg, K, Al, Fe, Mn, Ni, Cd and Se, by inductively coupled plasma mass spectrometry (ICP-MS). The mean atmospheric concentrations over the SO were 1100 ng m−3 for Na, 190 ng m−3 for Mg, 150 ng m−3 for Al, 14 ng m−3 for Fe, 0.46 ng m−3 for Mn and 0.25 ng m−3 for Se. Over CEA, the mean concentrations were 990 ng m−3 for Na, 180 ng m−3 for Mg, …

Palaeoenvironments and palaeoceanography changes across the Jurassic/Cretaceous boundary in the Arctic realm: case study of the Nordvik section (north Siberia, Russia)

Victor A. Zakharov,

Mikhail A. Rogov,

Oksana S. Dzyuba,

Karel Žák,

Martin Košt’ák,

Petr Pruner,

Petr Skupien,

Martin Chadima,

Martin Mazuch,

Boris L. Nikitenko

Опубликована Март 25, 2014

The Jurassic/Cretaceous transition was accompanied by significant changes in palaeoceanography and palaeoenvironments in the Tethyan Realm, but outside the Tethys such data are very scarce. Here we present results of a study of the most complete section in the Panboreal Superrealm, the Nordvik section. Belemnite δ18O data show an irregular decrease from values reaching up to +1.6‰ in the Middle Oxfordian and from +0.8 to −1.7‰ in the basal Ryazanian, indicating a prolonged warming. The biodiversity changes were strongly related to sea-level oscillations, showing a relatively low belemnite and high ammonite diversity during sea-level rise, accompanied by a decrease of …

Walruses recovering after 60+ years of protection in Svalbard, Norway

Kit M. Kovacs,

Jon Aars,

Christian Lydersen

Опубликована Окт. 7, 2014

Walruses were brought to the brink of extinction in Svalbard (Norway) during 350 years of unregulated harvesting. They became protected in 1952, when few remained. During the first 30 years of protection, approximately 100 animals became established within the archipelago, most of which likely came from Franz Josef Land, to the east. A marked recovery has taken place since then. This study reports the results of a photographic aerial survey flown in summer 2012, covering all current and historical haul-out sites for walruses in Svalbard. It provides updates regarding the increasing numbers of: (1) land-based haul-out sites (from 78 in …

Assessing the importance of human activities for the establishment of the invasive Poa annua in Antarctica

Marco A. Molina-Montenegro,

Fernando Carrasco-Urra,

Ian Acuña-Rodríguez,

Rómulo Oses,

Cristian Torres-Díaz,

Katarzyna J. Chwedorzewska

Опубликована Июнь 23, 2014

Because of its harsh environmental conditions and remoteness, Antarctica is often considered to be at low risk of plant invasion. However, an increasing number of reports have shown the presence and spread of non-native plants in Antarctica; it is therefore important to study which factors control the invasion process in this ecosystem. Here, we assessed the role of different human activities on the presence and abundance of the invasive Poa annua. In addition, we performed a reciprocal transplant experiment in the field, and a manipulative experiment of germination with P. annua and the natives Colobanthus quitensis and Deschampsia antarctica, in …

Species distribution and depth habitat of recent planktic foraminifera in Fram Strait, Arctic Ocean

Theodora Pados,

Robert F. Spielhagen

Опубликована Май 27, 2014

To describe the horizontal and vertical distribution of recent planktic foraminifera in Fram Strait (Arctic), plankton samples were collected in the early summer of 2011 using a MultiNet sampler (>63 µm) at 10 stations along a west–east transect at 78°50′N. Five depth intervals were sampled from the sea surface down to 500 m. Additionally, sediment surface samples from the same locations were analysed. The ratio between absolute abundances of planktic foraminifera in the open ocean, at the ice margin and in the ice-covered ocean was found to be approximately 2:4:1. The assemblage was dominated by the polar Neogloboquadrina pachyderma …

Long-term temperature trends and variability on Spitsbergen: the extended Svalbard Airport temperature series, 1898-2012

Øyvind Nordli,

Rajmund Przybylak,

Astrid E.J. Ogilvie,

Ketil Isaksen

Опубликована Янв. 22, 2014

One of the few long instrumental records available for the Arctic is the Svalbard Airport composite series that hitherto began in 1911, with observations made on Spitsbergen, the largest island in the Svalbard Archipelago. This record has now been extended to 1898 with the inclusion of observations made by hunting and scientific expeditions. Temperature has been observed almost continuously in Svalbard since 1898, although at different sites. It has therefore been possible to create one composite series for Svalbard Airport covering the period 1898–2012, and this valuable new record is presented here. The series reveals large temperature variability on Spitsbergen, …