Authors: 
Angelika Renner*, Marie Dumont**, Sebastian Gerland*, Justin Beckers***, Mats Granskog*, Harvey Goodwin*, Christian Haas***
*Norwegian Polar Institute, Fram Centre, Tromsø, Norway
**Météo France - CNRS, CNRM-GAME URA 1357, CEN, Grenoble, France
***University of Alberta, Edmonton, Canada
Conference Where Poster was Originally Presented:
AGU Fall Meeting 2011
Abstract/Summary:
In this poster, we present results from sea ice thickness surveys conducted during several scientific cruises in 2010 and 2011 in the region north of Svalbard and along 79° N in Fram Strait using a helicopter-borne electromagnetic device (EM-bird) in combination with aerial photography. A camera was mounted in the helicopter looking downwards at the EM-bird and the sea ice underneath and photos were taken every five seconds. A method based on discriminant analysis was developed to retrieve the fractions of the different ice types from the aerial photos. These fractions of open water, ice, thin ice, melt ponds and submerged ice were then combined with the ice thickness simultaneously measured by the EM-bird. The combination of ice thickness and ice type information provides insight into the characteristics of the different ice regimes and changes within these regimes. For example in Fram Strait in late summer 2010, the modal ice thickness was 1.2 m with the exception of a flight over the fast ice off the east coast of Greenland. There, the modal thickness was 2.9 m for a wide section of heavily ridged ice in front of the smoother, 1 m thick, level fast ice. As usual for the season, the sea ice was largely covered by melt ponds. However, the photo analyses show no significant difference between the fraction of melt ponds over ridged and level fast ice for this summer. The ice was thinner than expected, indicating the export of younger ice from the inner Arctic Ocean than in previous years. While the sea ice in Fram Strait is dominated by ice exported from the north, the ice cover north of Svalbard consists mostly of first-year ice. In summer 2010, this was visible in a narrower thickness distribution than in Fram Strait and a different distribution of the ice class fractions from the photographs.
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Authors: 
Chas Jones*, Larry Hinzman*, and Knut Kielland**
* International Arctic Research Center, University of Alaska Fairbanks, USA
** Institute for Arctic Biology, University of Alaska Fairbanks, USA
Conference Where Poster was Originally Presented:
American Geophysical Union, 2011, San Francisco, CA
Abstract/Summary:
The headwaters of the expansive Yukon River Basin are found to the south of much its contributing area and begin in British Columbia, Canada, flowing northwesterly through the Yukon Territory and continues flowing to the southwest through Alaska. Residents of Tanana, Alaska often harvest driftwood from the Yukon River during two different periods most summers. Typically, a lot of driftwood accompanies high flows on the Yukon River associated with spring break-up. A few weeks later, a second plug of driftwood frequently associates the “2nd rise”, which is reported to occur during early June. This study examines the nature of the differential timing of high flow events in the Yukon River. Many communities in interior Alaska have grown to rely upon driftwood as an important source of wood, which is used in construction, carving, and as an energy source. Increasingly, villages in rural Alaska are trying to lessen their dependence upon high-cost fossil fuels and other non-renewable energy sources. A number of Alaskan villages have recently installed wood chip-fired boilers to generate heat and/or electricity and additional boilers are slated to be installed in rural Alaska in the near future. These boilers are largely fed by driftwood, of the cheapest and most easily processed sources of wood, but how reliable is the driftwood harvest in the Yukon River? How might historic fluctuations in river hydrology affect the driftwood harvest? Local knowledge is used in conjunction with U.S. census, hydrologic, and climate reanalysis datasets to assess these questions. It appears that since 1995, high flow events have had a decreased magnitude compared to the period between 1977 and 1994. Based upon this observation and numerous assumptions, the average annual driftwood harvest in Tanana since 1995 was modeled as having increased compared to the average prior to 1994. This was largely driven by a change in the frequency and duration of high flow events.
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Authors: 
Wilkinson, P.T., Cockell, C.S., Olsson-Francis, K. Anand, M.
The Open University, Walton Hall, Milton Keynes, Buckinghamshire, MK7 6AA, United Kingdom
Conference Where Poster was Originally Presented:
Extremophiles 2010
Abstract/Summary:
Terrestrial basalt rock accounts for 30 to 35% of global atmospheric CO2 draw down by silicate weathering [1], a significant portion of total global CO2 flux. Thus, volcanic basalt is of extreme importance to current climate concerns. Despite these concerns however very little is understood about the endemic microbial community within these rocks. Recent work by Cockell et al [2] has gone someway in addressing the problem by applying culture and molecular techniques to identifying microbial lineages in cold Icelandic hyaloclastite and palagonite. Continued work by this group has indentified thermophilic Geobacillus in hyaloclastite and vesicular basalt rock, a surprising result considering the yearly average atmospheric temperature of the Icelandic sample site is +4°C, well below the minimal growth temperature of the identified thermophiles.
This work focused on the determination of in situ activity of these thermophiles and their susceptibility to heavy metals at varying growth temperatures. The thermophiles were isolated and identified as thermophilic Geobacillus. The optimal temperature of these thermophiles was between 65°C and 70°C in rich organic media. In this media the minimal growth temperature of any isolate, as define as a continuous increase in optical density over 5 hours was 38°C. On more defined basal media the minimum growth temperature of any thermophilic isolate was determined to be 32°C.
In order to determined the in situ activity of these thermophiles temperature data loggers were placed in representative rocks in the field. The peak surface rock temperature was 45°C, 20°C above atmospheric temperature and 13°C above the minimal growth temperature of isolated thermophiles. When considering possible in situ growth of these thermophilic bacteria we need to consider heavy metal concentrations in the rock. Susceptibility to Cu, Ni, Cr and Zn at different temperatures was determined via growing am isolate in rich organic media ‘spiked’ with the desired concentration of heavy metal. Results indicated that as temperature increased, heavy metal toxicity also increased. This is theorized to be due to increased plasma membrane fluidity and thus permeability as temperature increases.
This work describes the possible activity of thermophilic bacteria in cold basalt rock a detail previously overlooked when considering the effect of the microbial community associated with basalt rock on silicate weathering.
Work was supported by the Science and Technology Facilities Council and the Open University
1. Dessert, C., et al., Basalt weathering laws and the impact of basalt weathering on the global carbon cycle. Chemical Geology, 2003. 202(3-4): p. 257-273.
2. Cockell, C.S., et al., Bacteria in Weathered Basaltic Glass, Iceland. Geomicrobiology Journal, 2009. 26(7): p. 491 - 507.
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Authors:
Sina Schneider*, Christian Hauck*, Martin Hoelzle*
*Alpine Cryosphere and Geomorphology (ACAG), Department of Geosciences,
University of Fribourg, Switzerland
Originally presented at:
Not previously presented
Abstract/Summary:
Permafrost in high mountain areas occurs in a great variation of surface and subsurface material and texture within short distances. Therefore, the thermal regime of the subsurface strongly depends on site-specific factors like the grain size, the pore volume and type of material beside climatic factors such as air temperature, incoming radiation and precipitation.
To fulfill a long-term aim, the analysis of the sensitivity of high mountain permafrost to climatic changes, an electrical resistivity tomography (ERT) as a regularly measured monitoring was installed. Performing geoelectrical measurements in permafrost regions implies that changes in the resistivity are due to different subsurface materials and to phase change processes of water/ice. A regularly monitoring of the subsurface allows to detect seasonal as well as annual changes of resistivity values and is therefore a useful method to analyse and predict the development of periglacial material. This poster presents two ERTM- data sets measured since 2009 for three different periglacial forms. It illustrates well the annual changes in the resistivity values and the different development of the active layer and the freezing front.
Two ERTM’s were installed (one during summer 2009 and the other in 2010). Both are situated within the well investigated Murtèl-Corvatsch Area (Haeberli, W. et.al 1988, Vonder Mühll et.al 2001), covering three different periglacial forms: bedrock, talus slope and rock glacier. To verify the ERTM- data, borehole temperature data (the ERTM- profiles are placed beneath two boreholes (Hanson, S. & Hoelzle, M., 2005)) was used and refraction seismic tomography (RST) was performed ones a year. For using the change of resistivity as an implication for changes in the water/ ice content, the resistivity for the frozen and unfrozen state of each investigated material was measured and verified by the borehole temperature data. To analyse seasonal changes in resistivity, ERTM-measurement were performed every 2 months and to estimate the annual changes in resistivity values, the summer ERT- data as well as the RST- data (measured in mid-august) of each year were compared.
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Authors: 
Steven Reeves*, David G. Long*
* Microwave Earth Remote Sensing Lab at Brigham Young University, Provo, UT
Originally presented at:
Not previously presented
Abstract/Summary:
Sea ice extent can be estimated from a variety of active and microwave instruments. Scatterometers are active microwave instruments that have proven useful at estimating the ice extent from measured radar backscatter. This poster presents a method to detect sea ice using enhanced resolution images from the Advanced Scatterometer (ASCAT).
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Authors: 
Alek Petty*, Daniel Feltham*, and Paul Holland**
*CPOM, UCL - London, UK
** British Antarctic Survey, Cambridge, UK
Originally presented at:
ResClim Summer School
Abstract/Summary:
The temperature of waters above the shelf seabed in the Amundsen and Bellingshausen (AB) seas, Antarctica, is seen to be several degrees warmer than in the Weddell and Ross (WR) shelf seas. In the AB seas, unmodified Circumpolar Deep Water from the Antarctic Circumpolar Current floods the continental shelf all year round, while in the WR seas the cold wintertime mixed layer reaches the seabed. We want to test the hypothesis that the difference in shelf water properties is due to differences in the atmospheric forcing between the two regions. To do this we have developed a simple sea ice-mixed layer model to study the sensitivity of the wintertime mixed layer depth to a variation in surface fluxes. The study is also looking at the impact of initial water column profiles to see if a change in surface fluxes can result in a switch from one mode to the other. We shall later incorporate this mixed layer model into CICE to more accurately represent the buoyancy fluxes to the mixed layer from sea ice growth and melt during the annual sea ice cycle.
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Authors: 
Thomas Ernsdorf*, David Schröder*, Günther Heinemann*, Susanne Adams*, Alfred Helbig*, Ralph Timmermannn**, and Sascha Willmes*
*University of Trier, Fac. of Geography/Geosciences, Environmental Meteorology, Trier, Germany
**Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
Originally presented at:
European Geosciences Union (EGU), General Assembly, Vienna, Austria, May 02-07, 2010
Abstract/Summary:
The Laptev Sea polynyas play a key role for the shelf areas of the Siberian Arctic due to their impact on ice production. Changes in polynya dynamics result in modified fluxes of energy, momentum and matter in the atmosphere-ocean-sea ice system. An improved understanding and quantification of polynya effects in the Laptev Sea can be achieved by high-resolution sea ice-ocean models. Here we use the well-established Finite Element Sea Ice-Ocean Model FESOM (5 km x 5 km) (AWI Bremerhaven). It consists of a hydrostatic primitive-equation ocean model and a dynamic-thermodynamic sea ice model. In our study the model is forced by 6-hourly GME analyses (0.5° x 0.5°), daily and 6-hourly NCEP/NCAR reanalyses (2.5° x 2.5°) and hourly COSMO data (5 km x 5 km) to investigate a polynya event during the TRANSDRIFT winter experiment 2008. The input data consists of 10 m-wind, 2 m-temperature and specific humidity, total cloudiness and precipitation rate. In order to test the quality of the forcing data, comparisons with in-situ have been performed. They show shortcomings of the atmospheric analyses model data with respect to the daily course of the temperature, but very good agreement for the wind. The opening process of a main polynya event on 29 April 2008 is represented with all atmospheric forcing fields (except the daily NCEP data) in a similarly good way. However, there are differences in direction and velocity of the icedrift and in the location and development of the polynyas. Small-scale structures are best represented by applying the high-resolution COSMO data. The maximum sensible heat flux is 220 W/m2, the maximum latent heat flux is 120 W/m2, the maximum advective ice thickness reduction is 5 cm/h and the maximum thermal ice thickness production is 5 mm/h.
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Authors: 
S. Kohnemann *, G. Heinemann *, D. Schröder **, S. Willmes * and C. Koeberle ***
* University of Trier, Faculty VI Geography/Geosciences, Environmental Meteorology, Germany
** Centre for Polar Observation & Modelling, London, UK ,
*** Alfred Wegener Institut, Bremerhaven, Germany
Originally presented at:
EGU General Assembly 2011
Abstract/Summary:
Remote sensing data show a continuous decrease of sea ice in the past 30 years. Climate models predict a further decreasing for the future. Therefore, a closer analysis of the production processes, the trend development and the regional variability is necessary. The Laptev Sea plays an important role for the Arctic sea ice budget due to a high polynya activity at the Siberian coast. The coupled ocean-sea ice model NAOSIM (North Atlantic/Arctic Ocean- Sea Ice Model) is used for the study of thermodynamic and dynamic ice production processes for the whole Arctic for the period 1990-2008. The simulation is driven by daily NCEP/NCAR data, and the horizontal resolution of the model is about 9km. Sea ice concentration from satellite data is used for the verification of model results. The model is able to reproduce the mean annual cycle and the negative trend realistically. A detailed analysis of the thermodynamic sea ice production/melt and the dynamic redistribution for different regions of the Arctic shows that the mean sea ice production of the Laptev Sea area exceeds the sea ice melt rate by 740 km3/a. That sea ice volume is transported into the central Arctic. The net ice production in the Laptev Sea is as large as the net ice production in the central Arctic north of 80°N. The Laptev Sea is found to be the largest ice producer compared to other Arctic shelf areas. In addition, the interannual variability of sea ice production in the Laptev Sea is small compared to other regions. A negative trend of sea ice in the Laptev-Sea is not found. For the entire Arctic sea ice volume decrease amounts to the average of -450 km3/a from 1990 to 2008. Studies for years with extreme sea ice anomalies show no direct connections between the sea ice production of the Laptev Sea and the sea ice volume of the entire Arctic.
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Authors: 
Tore Hattermann* & Ole Anders Nøst*
*Norwegian Polar Institute, Tromsø, Norway
Originally presented at:
IGS symposium 2011, La Jolla
Abstract/Summary:
The Fimbul Ice Shelf in the Eastern Weddell Sea is the sixth largest Antarctic ice shelf, and feeds from Jotulstraumen, the largest ice stream in Dronning Maud Land, Eastern Antarctica. During the austral summer 2009/2010, three hot water boreholes were established to deploy oceanographic instrumentation beneath the Fimbul ice shelf. In addition each borehole was wired with a string of thermistors which record a time series of the vertical temperature profile within the ice.
Here we propose a one dimensional advection-diffusion type temperature model to describe the short term evolution of the observed temperature profiles within the ice. We explore the ability of the model to estimate the local basal mass balance, and compare our results to oceanographic observations below the boreholes. However, this method is based on the assumption, that the borehole has refrozen and its temperature is in horizontal equilibrium with the ambient ice, which is not necessarily true for our one-year time series.
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Authors: 
Philipp Griewank & Dirk Notz*
* Max-Planck-Institut für Meteorologie
Originally presented at:
EGU 2011 and ResClim Summer School on sea ice
Abstract/Summary:
This poster explores how the thermodynamics and desalination of sea ice can be simulated using a 1D model. To achieve this a new thermodynamic model based on first principles was developed by the authors. The relevant desalination processes (gravity drainage, flushing and flooding) are represented by newly designed parametrizations. After briefly outlining the approach used the new model is compared to lab data as well as run over two 4.5 year periods. Preliminary results are encouraging indicating that it is indeed possible to simulate sea-ice desalination using only a 1D model.
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Authors: 
Andreas Preußer*, Günther Heinemann*, and Clemens Drüe*
* Environmental Meteorology, University of Trier, Fac. of Geography / Geosciences, Trier, Germany
Conference Where Poster was Originally Presented:
European Geosciences Union General Assembly 2011 Vienna | Austria | 03 – 08 April 2011
Abstract/Summary:
The NorthWater polynya (NOW) forms recurrently between Ellesmere Island and northwest Greenland and is one of the largest and therefore most important polynyas in the northern hemisphere. It is considered to have a huge impact on atmospheric, biological and ocean processes. An investigation of polynya dynamics between 1996 and 2009 / 2010 has been performed using sea ice concentration (SIC) products from the passive microwave sensors SSM/I and AMSR-E. From SIC data we derived the total polynya area (POLA, SIC threshold of Smith Sound has a large
influence on the formation of the NOW. Time series for regions north and south of the bridge are used to identify the ice bridge characteristics associated with its influence on ice export through the Nares Strait. In addition to the long-term study, a case study for a polynya event on 19 March 2009 has been carried out using MODIS data and a surface energy model. MODIS ice surface temperatures and NCEP reanalysis data are used to derive the thermal ice thickness distribution and ice production. A mean ice production of 0.35 cm/h is calculated for this case study.
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Authors:
Elena Kuznetsova* & Rimma Motenko* 
* Lomonosov Moscow State University, geological, geocryology, Moscow, Russian Federation
Conference Where Poster was Originally Presented:
EGU 2011, Vienna, Austria
Abstract/Summary:
Geocryological prognosis and estimation of main permafrost characteristics (thickness, active layer depth) are impossible without thermal characteristics of the frozen grounds. The knowledge of phase composition of water in frozen ash is necessary for their interpretation. Thermal properties of the pyroclastic volcanic deposits are studied insufficiently. Generally existing data was received for volcanic massive rocks or tuffs and for thawed state.The analysis of available data was difficult because there is no information about age, humidity and density. We found out that the thermal conductivity of thawed frozen volcanic ashes and cinders is much lower than that of mineralogical grounds (clays, cinders, loams, sandy loams). It’s connected with mineralogical and granulometric composition and porosity of pyroclastic rocks and also with unfrozen water and ice content ratio for frozen ones.
The samples of different ages (from 35 till 8000 years old) were collected in the Kluchevskaya volcano group (Kamchatka). According to silicon dioxide the volcanic glass are divided into three types: andesite, basalt and rhyolite. Diagnostics of mineral structure for volcanic ash by IR–spectroscopy showed two amorphous minerals presence: opal and allophane. Opal is hydrated silicon dioxide. Allophane is hydrous aluminium silicate clay mineral. The particle density s and hygroscopic water Wg were in the range 2.1-2.79 g/sm3 and 0-7.3 %.
The regularity of dependences of unfrozen water (Ww) content on temperature ranging from 0 to –15oC obtained for all investigated ashes of different ages. There is no considerable change in the unfrozen water content in the temperature ranging from –3 till –15oC. And the range of unfrozen water content in the investigated ashes was from 0 to 11 %. Occurrence of the unfrozen water was presumably connected with transformation of volcanic glass depending on age and clay minerals (allophane) occurrence that have a high surface area. Measurements of thermal conductivity were made for volcanic ashes of different age, mineral, chemical and granulometric composition. On condition that the density and humidity (W) were changing from 0.7 to 1.65 g/sm3 and from 10 to 80 % accordingly the thermal conductivity increased from 0.37 to 1.0 W/(m K) in thawed state and from 0.41 to 1.27 W/(m K) in frozen state.
All properties of frozen grounds are formed by unfrozen water (Ww) and ice content (W–Ww) because the thermal conductivity of ice (2.2 W/(m K)) are larger than of water (0.56 W/(m K)). There was estimated the role of unfrozen water and ice content ratio in the forming of the thermal conductivity in the frozen volcanic ashes. In the ashes of opal composition, there is not much unfrozen water, the unfrozen water and ice content ratio is changing from 0 to 0.08.In the ashes of allophane composition, where unfrozen water content is changing from 2 to 11%, the ratio Ww=(W–Ww) is from 0,08 to 0,58.
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