Polar Research (E-Journal)
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The intraseasonal variability of winter semester surface air temperature in Antarctica
No full textThis study investigates systematically the intraseasonal variability of surface air temperature over Antarctica by applying empirical orthogonal function (EOF) analysis to the National Centers for Environmental Prediction, US Department of Energy, Reanalysis 2 data set for the period of 1979 through 2007. The results reveal the existence of two major intraseasonal oscillations of surface temperature with periods of 26 - 30 days and 14 days during the Antarctic winter season in the region south of 60°S. The first EOF mode shows a nearly uniform spatial pattern in Antarctica and the Southern Ocean associated with the Antarctic Oscillation. The mode-1 intraseasonal variability of the surface temperature leads that of upper atmosphere by one day with the largest correlation at 300-hPa level geopotential heights. The intraseasonal variability of the mode-1 EOF is closely related to the variations of surface net longwave radiation the total cloud cover over Antarctica. The other major EOF modes reveal the existence of eastward propagating phases over the Southern Ocean and marginal region in Antarctica. The leading two propagating modes respond to Pacific-South American modes. Meridional winds induced by the wave train from the tropics have a direct influence on the surface air temperature over the Southern Ocean and the marginal region of the Antarctic continent. Key words: Antarctic climate, surface air temperature, intraseasonal variability, Antarctic Oscillation (Published: 22 February 2011) Citation: Polar Research 2011, 30, 6039, DOI: 10.3402/polar.v30i0.603
An inter-comparison of six latent and sensible heat flux products over the Southern Ocean
No full textThe latent heat fluxes (LHF) and sensible heat fluxes (SHF) over the Southern Ocean from six different data sets are inter-compared for the period 1988- 2000. The six data sets include three satellite-based products, namely, the second version of the Goddard Satellite-Based Surface Turbulent Fluxes data set (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3) and the Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO); two global reanalysis products, namely, the National Centers for Environmental Prediction-Department of Energy Reanalysis 2 data set (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis data set (ERA-40); and the Objectively Analyzed Air-Sea Fluxes for the Global Oceans data set (OAFlux). All these products reveal a similar pattern in the averaged flux fields. The zonal mean LHF fields all exhibit a continuous increase equatorward. With an exception of HOAPS-3, the zonal mean SHF fields display a minimum value near 50°S, increasing both pole- and equatorward. The differences in the standard deviation for LHF are larger among the six data products than the differences for SHF. Over the regions where the surface fluxes are significantly influenced by the Antarctic Oscillation and the Pacific-South American teleconnection, the values and distributions of both LHF and SHF are consistent among the six products. It was found that the spatial patterns of the standard deviations and trends of LHF and SHF can be explained primarily by sea-air specific humidity and temperature differences; wind speed plays a minor role.Keywords: Latent heat flux; sensible heat flux; Southern Ocean(Published: 17 November 2011)Citation: Polar Research 2011, 30, 10167, DOI: 10.3402/polar.v30i0.1016
UV-B absorbing pigments in spores: biochemical responses to shade in a high-latitude birch forest and implications for sporopollenin-based proxies of past environmental change
No full textCurrent attempts to develop a proxy for Earth’s surface ultraviolet-B (UV-B) flux focus on the organic chemistry of pollen and spores because their constituent biopolymer, sporopollenin, contains UV-B absorbing pigments whose relative abundance may respond to the ambient UV-B flux. Fourier transform infrared (FTIR) microspectroscopy provides a useful tool for rapidly determining the pigment content of spores. In this paper, we use FTIR to detect a chemical response of spore wall UV-B absorbing pigments that corresponds with levels of shade beneath the canopy of a high-latitude Swedish birch forest. A 27% reduction in UV-B flux beneath the canopy leads to a significant (p<0.05) 7.3% reduction in concentration of UV-B absorbing compounds in sporopollenin. The field data from this natural flux gradient in UV-B further support our earlier work on sporopollenin-based proxies derived from sedimentary records and herbaria collections.Keywords: FTIR, spores, ferulic acid, p-coumaric acid, shade, sporopollenin(Published: 23 August 2011)Citation: Polar Research 2011, 30, 8312, DOI: 10.3402/polar.v30i0.831
Spatio-temporal variability of snowmelt across Svalbard during the period 2000-08 derived from QuikSCAT/SeaWinds scatterometry
No full textSignificant changes in Arctic systems are underway, which are attributed to global warming. An important example is reduction in snow and ice coverage due to intensified melting in many regions. Active microwave instruments are used to detect surface melt and freeze-up based on the high sensitivity of radar backscatter to liquid water in the snow.We monitor two snowmelt parameters, the annual total of melt days and the date of summer melt onset across the archipelago of Svalbard using microwave backscatter measurements from the Ku-band scatterometer SeaWinds onboard the QuikSCAT satellite. Our analysis covers a nine-year time span from 2000 to 2008. Meteorological data from synoptic and automatic weather stations at several locations in Svalbard are used to investigate climatologic controls on pattern and timing of snowmelt. Svalbard temperature and precipitation regimes are highly variable throughout the year due to the location of the archipelago within a zone that is characterized by the convergence of atmospheric fronts from the Arctic Ocean, Nordic seas and the Barents Sea. Accordingly, our results show pronounced regional and interannual variability in snowmelt dynamics. However, we do find a trend towards earlier summer melt onset and an increasing number of melt days per year over the nine-year period of study. Our findings agree with climate-model predictions that project increasingly warmer and wetter conditions in the Arctic. Keywords: Svalbard; radar remote sensing; snowmelt detection; climate variability; scatterometry (Published: 17 February 2011) Citation: Polar Research 2011, 30, 5963, doi: 10.3402/polar.v30i0.596
Foreword: Oslo Science Conference, 8-12 June 2010: selected IPY papers
No full textBilled as ‘‘the largest polar gathering ever’’, the Oslo Science Conference, held in June 2010, marked the conclusion of the fourth International Polar Year (IPY).As a country with management responsibilities for areas in both the Antarctic and the Arctic, Norway has been heavily involved in IPY activities and was proud to host the conference in Lillestrøm, outside of Oslo.(Published: 31 December 2011)Citation: Polar Research 2011, 30, 15941, DOI: 10.3402/polar.v30i0.1594
Near-bottom water warming in the Laptev Sea in response to atmospheric and sea-ice conditions in 2007
No full textIn this paper we present new data from ship-based measurements and twoyear observations from moorings in the Laptev Sea along with Russian historical data. The observations from the Laptev Sea in 2007 indicate that the bottom water temperatures on the mid-shelf increased by more than 3°C compared to the long-term mean as a consequence of the unusually high summertime surface water temperatures. Such a distinct increase in nearbottom temperatures has not been observed before. Remnants of the relatively warm bottom water occupied the mid-shelf from September 2007 until April 2008. Strong polynya activity during March to May 2007 caused more summertime open water and therefore warmer sea surface temperatures in the Laptev Sea. During the ice-free period in August and September 2007, the prevailing cyclonic atmospheric circulation deflected the freshwater plume of the River Lena to the east, which increased the salinity on the mid-shelf north of the Lena Delta. The resulting weaker density stratification allowed more vertical mixing of the water column during storms in late September and early October, leading to the observed warming of the near-bottom layer in the still ice-free Laptev Sea. In summer and autumn 2008, when the density stratification was stronger and sea surface temperatures were close to the long-term mean, no near-bottom water warming was observed. Warmer water temperatures near the seabed may also impact the stability of the shelf’s submarine permafrost.Keywords: Siberian Shelf seas; shelf oceanography; sea ice; atmospheric forcing(Published: 12 May 2011)Citation: Polar Research 2011, 30, 6425, DOI: 10.3402/polar.v30i0.642
Community vulnerability to climate change in the context of other exposure-sensitivities in Kugluktuk, Nunavut
No full textClimate change in the Canadian north is, and will be, managed by communities that are already experiencing social, political, economic and other environmental changes. Hence, there is a need to understand vulnerability to climate change in the context of multiple exposure-sensitivities at the community level. This paper responds to this perceived knowledge need based on a case study of the community of Kugluktuk in Nunavut, Canada. An established approach for vulnerability assessment is used to identify current climatic and non-climatic exposure-sensitivities along with their associated contemporary adaptation strategies. This assessment of current vulnerability is used as a basis to consider Kugluktuk’s possible vulnerability to climatic change in the future. Current climate-related exposure-sensitivities in Kugluktuk relate primarily to subsistence harvesting and community infrastructure. Thinner and less stable ice conditions and unpredictable weather patterns are making travel and harvesting more dangerous, and some community infrastructure is sensitive to permafrost melt and extreme weather events (e.g., flash floods). The ability of individuals and households to adapt to these and other climatic exposure-sensitivities is influenced by non-climatic factors which condition adaptive capacity, including substance abuse, the erosion of traditional knowledge and youth suicide. These and other non-climatic factors often underpin adaptive capacity to deal with and adapt to changing conditions and must be considered in an assessment of vulnerability. This research argues that Northern communities are challenged by multiple exposure-sensitivities, beyond just those posed by climate, and effective adaptation to climate change requires consideration if not resolution of socio-economic and other issues in communities.
Keywords: Climate change; Arctic; community vulnerability; adaptation; Inuit
(Published: 27 July 2011)
Citation: Polar Research 2011, 30, 7363, DOI: 10.3402/polar.v30i0.736
Oil spill emergency preparedness in the Russian Arctic: a study of the Murmansk region
No full textThe issue of oil spill emergency response in north-west Russia has become increasingly important following a substantial increase in maritime transport and major offshore developments in Russian waters. This study is an initial effort to outline the public and private agencies and organizations involved in handling oil spills in the Murmansk region and the structure of the oil spill emergency response system in the region. This study examines the formal relationships between federal and regional authorities and between the different subsystems at the regional level. Due to the paucity of academic literature and public documentation on this topic, this study to a large extent bases itself on interview data. A main finding is that the regional oil spill response system has not been fully developed. It further concludes that the system lacks a clearly formulated state policy, a single governing authority and a unified structure. Finally, the study demonstrates that the agencies and organizations involved in tackling oil spill emergencies in the Murmansk region are hampered by insufficient funding, which probably reduces their preparedness to combat oil spills.Keywords: oil spills; oil spill emergency response; organizations(Published: 9 June 2011)Citation: Polar Research 2011, 30, 7285, DOI: 10.3402/polar.v30i0.728
Impact of Laptev Sea flaw polynyas on the atmospheric boundary layer and ice production using idealized mesoscale simulations
No full textThe interaction between polynyas and the atmospheric boundary layer is examined in the Laptev Sea using the regional, non-hydrostatic Consortium for Small-scale Modelling (COSMO) atmosphere model. A thermodynamic sea-ice model is used to consider the response of sea-ice surface temperature to idealized atmospheric forcing. The idealized regimes represent atmospheric conditions that are typical for the Laptev Sea region. Cold wintertime conditions are investigated with sea-iceocean temperature differences of up to 40 K. The Laptev Sea flaw polynyas strongly modify the atmospheric boundary layer. Convectively mixed layers reach heights of up to 1200 m above the polynyas with temperature anomalies of more than 5 K. Horizontal transport of heat expands to areas more than 500 km downstream of the polynyas. Strong wind regimes lead to a more shallow mixed layer with strong near-surface modifications, while weaker wind regimes show a deeper, well-mixed convective boundary layer. Shallow mesoscale circulations occur in the vicinity of ice-free and thin-ice covered polynyas. They are forced by large turbulent and radiative heat fluxes from the surface of up to 789 W m-2, strong low-level thermally induced convergence and cold air flow from the orographic structure of the Taimyr Peninsula in the western Laptev Sea region. Based on the surface energy balance we derive potential sea-ice production rates between 8 and 25 cm d-1. These production rates are mainly determined by whether the polynyas are ice-free or covered by thin ice and by the wind strength. Keywords: Mesoscale modelling; polynyas; sea-ice production; Laptev Sea (Published: 31 May 2011) Citation: Polar Research 2011, 30, 7210, DOI: 10.3402/polar.v30i0.721
Review of Paleoclimates. Understanding climate change past and present, by Thomas M. Cronin
No full textA strong demand for a better understanding of past climate changes and their controls becomes evident when looking at the anthropogenically accelerated rapid warming during the past few centuries. In his book Paleoclimates, Thomas Cronin provides an excellent review and stimulating discussion of the state of art and current hot topics in this socio-economically important discipline to the scientific community of palaeoclimate researchers and students in this field.(Published: 14 January 2011)Citation: Polar Research 2011, 30, 5927, doi: 10.3402/polar.v30i0.592