2008 report
Progress: 60 %
About 60% of the task work was completed so far. Most of the work issues contribute directly or indirectly to addressing the overarching issue of Task 1.4 (see Annex 1 DoW).
Milestones:
The following milestones were due or partly due in this project period:
M1.4-1: Design of an integrated field study with remote sensing, manned and automated in situ observations (Month 16)
M1.4-2: Deployment of the MOPS in Storfjorden (Month 16)
M1.4-3: Test of automatic albedo measurement setup (Months 6 and 18)
M1.4-4: Installation of automatic albedo measurement setups at ice drift stations (Months 17 and 22)
M1.4-5: Receiving data from automatic sensors, processing and integration with satellite remote sensing data. Collection of datasets from in situ manned sea ice camps and remote sensing (Months 24 and 36)
All milestones listed above were reached (M1.4-5 partly according to the plan) and reported. M1.4-3 needed modification, since the plan with Tara drifting 2 years changed (faster drift over the Arctic Basin). The first part of M1.4-5 will be reported in month 24, as planned. M1.4-5 possibly will also need modification according to new fieldwork plans for 2008.
Deliverables:
D1.4-2: Month 19: Preliminary statements concerning frazil ice formation in the Arctic Ocean transpolar drift (UPMC) – Delivered in month 26.
D1.4-3: Month 24: Brines production based on 3 years of observations and assessment concerning thermodynamical factors influencing sea-ice formation in Storfjorden (UPMC) – Delayed to month 29.
D1.4-4: Month 24: Model sensitivity study report and guidelines for large scales models (FIMR) - Was delivered according to the plan.
Activities:
- Marcel Nicolaus, postdoc scientist (sea ice physics, NPI) employed (March 2007)
- Fieldwork planning and coordination: Inglefieldbukta (“Vagabond”/Storfjorden, Svalbard), “Tara”/Arctic Basin, KV “ Svalbard” ( Fram Strait), and RV “Lance”/ Fram Strait, (NPI, FIMR, UPMC, AWI)
- 4 Fieldwork/large lab experiment activities:
a) Inglefieldbukta/Storfjorden radiometer measurements and snow/sea ice survey, oceanographic measurements (March 07 and beyond; NPI, UPMC)
b) Arctic Basin/” Tara” fieldwork (optical measurements and installations, snow and ice physics and texture, monitoring setup (April 07 and beyond; all, AWI)
c) NPI Fram Strait cruise with KV “Svalbard”, drifting ice stations with albedo and physical property measurements in level and ridged ice (April 07; NPI)
d) NPI Fram Strait cruise with RV “Lance”, ice stations with albedo and physical property measurements in level and ridged ice (September 07; NPI, FIMR)
e) Ice tank experiment Hamburg HSVA with optical measurements and ice physics (NPI).
- Field data processing, documenting and reporting (all)
- Coordination and support of the long term monitoring program at Tara (since April 2007, ongoing, all)
- Calculation of drift forecasts for the Tara drift for scientific and logistical planning (NPI)
- Logistical support with research equipment handling, storage and paperwork processing (freight, customs etc.) through NPI's offices in Longyearbyen, Svalbard, and in Tromsø, for Damocles field activities (NPI)
- Outreach: Book chapter (5: “Ice in the Sea”) in UNEP book “Global Outlook for Ice and Snow”, Article in leading Norwegian Newspaper “Aftenposten” (May 2007), several Damocles-related website articles on the NPI website, discussions and cooperations with various journalists related to the Tara field work (mainly French media).
- Publication activities: submission of manuscript for publication on the Tara drift scientific work to the journal Eos Transactions (was accepted in November 2007 and is now in press; authors include several task 1.4 participants); submission and acceptance of contributions for presentations at the AGU Fall Meeting December 2007 (Gerland et al. 2007, Nicolaus et al. 2007); presentation at the eastern Snow Conference in Canada in May/June 2007 (F. Domine).
- Website contribution for the Damocles website written and designed, regarding task 1.4 (draft circulated, but not yet implemented in website)
- Participating in Workshops and Meetings: Damocles GA I (Bremen, December 2006), Eastern Snow Conference (Canada, May/June 2007), Sea Ice Summer School (Longyearbyen, July 2007), WP1 workshop (Villefranche, France, October 2007), IPY-NySMAC Seminar (Cambridge, UK, Oct. 2007), CryoSat-2 CalVal Team meeting (Estec, Netherlands, October 2007), S4D Workshop (Paris, October 2007), Damocles GA II (Oslo, November 2007)
- Snow and Sea Ice Modelling advancements (FIMR)
Summary reports from individual partner institutions in task 1.4:
NPI (Sebastian Gerland, Marcel Nicolaus, Edmond Hansen, Olga Pavlova):
During months 13-24, NPI scientists contributed extensively to task 1.4. In March 2007, Marcel Nicolaus was employed as the new Damocles sea ice postdoc for NPI.
The most central activity was the sea ice study at “ Tara” in the Arctic Basin, which included measurements of optical, physical and textural properties of snow and ice, and installation and implementation of automatic and manned snow and sea ice monitoring during her travel with the transpolar drift. Advanced optical measurements of spectral surface albedo and spectral snow and ice transmittance were done with an automatic setup, and the system worked successfully the entire measurement period from April to September 2007, as well as the related snow and sea ice data set are looking promising. By that, the complete transition of the sea ice system could be covered, from winter sea ice conditions to melting conditions in summer, and finally to the onset of freezing and new snowfall.
The work at Tara was supplemented by fieldwork at “Vagabond” in Inglefieldbukta, Storfjorden ( Svalbard), in the Fram Strait during both a KV “ Svalbard” and a RV “Lance” expedition, and in an ice tank-laboratory experiment in Hamburg, Germany. In several of the fieldwork activities, Damocles is benefiting from related projects, funded by the Research Council of Norway (national IPY funding), the EU or the NPI (long term monitoring). The fieldwork demanded extensive logistical preparations, report writing and data processing. The data processing is ongoing, internal field reports have been written to a large degree. First results will be presented at the Damocles GA In Oslo in November 2007, and at the Fall Meeting of the AGU in San Francisco, in December 2007. An article about the scientific programme during the Tara drift, lead by J.-C. Gascard (with co-authorship of S.Gerland and M. Nicolaus), is currently in press at Eos Transactions of the AGU. A talk reporting on Svalbard fast ice, including Storfjorden near Vagabond, was given at the IPY NySMAC seminar in Cambridge, UK, in October 2007.
Regarding dissemination, activities and preliminary results have been published or reported in newspaper articles (e.g. Aftenposten, leading Norwegian newspaper), website articles (NPI website, Damocles website), radio and TV contributions (NRK Norway, Deutschlandfunk). General findings about sea ice were also communicated in a book chapter (UNEP: Global Outlook for Ice and Snow). Several meetings (conferences, workshops, project or work package meetings) have been attended by the NPI sea ice Damocles team.
Marcel Nicolaus strongly benefited from participating at the Damocles “sea ice summer school” (Longyearbyen, Svalbard). Discussions with many participants (students and lecturers) were very fruitful, efficient and inspiring.
UPMC (Jean-Claude Gascard):
Main activities concern works done at three different sites: Storfjord (Vagabond), Tara and in the central Arctic Ocean in relation with ITP and IMB deployments.
In Storfjord we completed a third year of observations mainly dealing with brines formation in relation with sea ice formation, atmospheric forcing, ocean circulation and water masses distribution. The data collection encompasses meteorological data, CTD data and sea ice data with a new system named IceT for measuring sea ice thickness, temperature profiles across the ice and surface currents (PI. Frederic Vivier). Most of the other data collected in Storfjord during this third year were under the responsibility of Eric Brossier, captain of Vagabond. One of the most striking result (still under investigation) resides in the fact that despite very different meteorological conditions occurring during the past 3 winters, brines formation in Storfjord is very similar every year and characterized by a sudden invasion of the water column from near surface to bottom by the cold and salty brines late march-early april. During the forth and fifth year research activities in Storfjord at Vagabond will be strongly reinforced.
The second type of activities at Tara drifting across the Arctic Ocean with the transpolar drift between September 2006 (northern Laptev Sea) to Fram Strait (end of 2007), concerns mainly deep ice (frazil) formation. Our attention was alerted during the past winter at a time when it seemed like all the instruments operating in the upper ocean, had a strange behaviour. This was more likely due to a very active frazil ice formation that lasted most of the winter. The instruments involved are a Seabird microcat CTD, a Seabird CTD profiler and a bottom echo sounder (Furuno 28 khz). These measurements are actually continuing on board Tara for the second winter and again similar phenomena were observed still under investigation.
The third type of activities concerns ITP (Ice Tethered Platforms) and IMB (Ice Mass Balance) array deployed in the Central Arctic in cooperation with US scientists and engineers from WHOI ( ITP) and CRREL (IMB). Initially three Polar Ocean Profiling System (POPS) were deployed at the same time Tara started to drift in September 2006. Three IMBs were also deployed (one of them being at Tara and the two others together with the POPS). The IMB at Tara broke during a storm mid September when all the ice floes broke too. In April 2007 two more POPS were deployed (one of them at Tara) and the Tara broken IMB was replaced by a new one.
During the past summer 2007 in conjunction with the Akademik Fedorov cruise for deploying the Russian drifting station NP35, five ITPs (WHOI type) were deployed and 3 IMBs + Ice T.
The MOPS (equivalent to POPS but moored to the bottom instead of being tethered to the drifting ice) was not deployed in Storfjord as anticipated for undergoing some test. It was deployed directly on Yermak Plateau in 700m of water in July 2007 from Hakon Mosby in cooperation with the Geophysical Institute in Bergen (PI. I. Fer). This activity we refer to in WP3-2.
FIMR (Jari Haapala, Bin Cheng, and Eero Rinne):
FIMR participated for the Tara field campaign, April 2007, deployed two thermistors strings for monitoring snow/ice temperature, a time-lapse camera for monitoring surface changes and contributed to the in-situ measurements. The sea-ice and snow monitoring program were initiated and the Tara crew was trained to continue measurements.
During the summer-autumn 2007 FIMR has received sea-ice measurement data from Tara. The data includes sea-ice density, salinity, thickness and freeboard measurements. Data have been processed and basic analyses have been made. In November, FIMR received the Karhukamera – a time-lapse photography unit which was installed onboard TARA since 28 April 2007. System was set up to take high resolution photographs of the radiometer and thermistor measurement site (10 min. intervals). System has been successfully operating until 22 July 2007, producing 12154 photographs. Photographs and time-lapse videos illustrating conditions of measurement site are available at the karhukamera.com -website at http://www.karhukamera.com/.
FIMR has continued thermodynamical modelling of sea-ice with the HIGTHSI model. The model experiments have been made in order to study an effect of snow on sea-ice mass balance. Key finding is that the snow is very important for sea ice mass balance in the Arctic Ocean, but a proper modelling of the evolution of the snow depends highly on the quality of the atmospheric forcing since the snow thickness depends on the precipitation. A proper modelling of the seasonal evolution of the snow and ice depends also highly on the surface albedo and the snow melting processes. The model experiments have been made with different parameterizations of the surface albedo, and a time dependent surface albedo parameterization scheme was found to produce the most realistic results. The HIGHTSI model has also been used for examinations of the possible bias of the climate simulations due to the simplification of the vertical structure of heat within the sea-ice. In these experiments, a vertical resolution of the model was varied in order to obtain simulation representing Semtner 0-level, Semtner 3-level and Maykut-Untersteiner type sea-ice models. The coarse resolution models can't take a penetration of the solar radiation account which cause that those models produce too little variability in temperature profile, increase the sensitivity to the change of surface albedo and mass balance, delay the on-set of ice melting and are not be able to re-produce a process called sub-surface melting and simulate incorrectly the superimposed ice formation.
Susanne Hanson, DNSC:
During the drift of the TARA 2006 – 2008 a specific snow program has been conducted of the crew onboard. This program includes snow thickness measurements, snow density and temperature and a full description (and a simplified classification) of the stratigraphy at a regular basis.
A member of the first crew was trained during summer 2006 and the snow program was initialized during fall 2006. This was not an easy ask for the crew and the conditions in the arctic ocean contributed to the difficult start of this program. Also the poor possibilities of direct communication between scientist and crew underlined that this work was difficult for layman. Since January 2007 the program has been running smoother.
In spring 2007 visiting scientist did further detailed measurements of the very same physical parameters along a validation line. This work has been continued during the summer and fall by the crew onboard TARA.
LGGE (Florent Domine):
The contribution of LGGE was focused on snow physical properties around TARA. Besides the standard snow stratigraphy studies (digging snow pits, observing the stratigraphy, measuring density), the measurements consisted in :
1- Measuring the specific surface area (SSA) of snow. Snow SSA determines the scattering part of albedo. SSA is directly related to the equivalent sphere size (SSA=3/ri r) where r is the sphere radius and ri is the ice density. SSA therefore represents an unambiguous alternative to the fuzzy definition of grain size. It is essential for the field validation of airborne or satellite optical data. SSA measurements were done using a novel method used for the first time for this campaign. A snow sample was illuminated with a laser diode at 1310 nm. All the reflected light was integrated with an integration sphere, and detected with an InGaAs photodiode. Most measurements were on the very surface layer of the snowpack, but several snowpits were dug, where all layers were measured. This new system worked well in the field. Data analysis and subsequent calibration showed that the conversion of the signal into SSA values was more complex that expected, and that modeling was required. Retrieval algorithms are being designed.
2- A survey of outcropping layers was done to quantify the distribution of surface snow layers. This is necessary to upscale our field measurements and to relate them to airborne data.
3- Measuring the heat conductivity of snow. Several snowpits were dug and the heat conductivity of all layers was measured, from which the thermal resistance of the snowpack is deduced.
References:
J-C. Gascard, E. Bourgois, H. Bourmaud, B. Buigues, B. Bruemmer, K. Claffey, M. Doble, F. Dominé, B. Elder, J. Festy, R. Forsberg, S. Gerland, H. Le Goff, J. Grangeon, J. Haapala, C.Haas, S. Hanson, G. Heygster, E. Jakobsson, L. Kaleschke, C. de Marliave, J-P. Metaxian, M. Nicolaus, M. Offermann, T. Palo, G. Redvers, E. Rinne, H. Skourup, R. Troublé, P. Wadhams, M. Weber, J. Wilkinson (in press): The Tara Damocles transpolar drift, 112 years after Fram. Eos Transactions, American Geophysical Union.
S. Gerland, Aars, J., Bracegirdle, T., Carmack, E., Hop, H., Hovelsrud, G.K., Kovacs, K.M., Lydersen, C., Perovich, D.K., Richter-Menge, J., Rybråten, S., Strøm, H., & Turner, J. (2007). Ice in the Sea. Chapter 5 of Global Outlook for Ice and Snow.UN Environment Program (UNEP), pp. 63-96. Website with download link: http://www.unep.org/geo/geo_ice/
F. Domine and J.-C. Gallet (2007) Retrieving snow grain size and specific surface area from infrared reflectance. Eastern Snow Conference, St John's, Newfoundland, Canada.
M. Nicolaus (2007) Colours of snow and sea ice – physical surface properties during spring and summer. Sea ice summer school, Longyearbyen, Svalbard, poster presentation.
Gerland, S., Gascard, J.-C., Ivanov, B., Nielsen, C.-P., Nilsen, F., Pavlova, O., Leu, E., Tverberg, V. , & Barrault, S. (2007): Fast ice evolution in Kongsfjorden compared with other Svalbard fjords. Talk. NySMAC Seminar: Ny-Ålesund and IPY, Cambridge, U.K., 16-17 October 2007.
S. Gerland, Haas, C., Goodwin, H., Nicolaus, M., Nicolaus, A., Hansen, E., & Renner, A.H.H. (2007): In situ thickness observations of sea ice and snow in the Fram Strait. Talk (invited). Fall Meeting of the American Geophysical Union, San Francisco, USA, December 2007.
M. Nicolaus, S. Gerland, and C.A. Pedersen (2007): Seasonal Variability of Snow Stratigraphy and Spectral Optical Properties on Sea Ice. Fall Meeting of the American Geophysical Union, San Francisco, USA, December 2007, poster presentation.
Website links:
Ice tank experiments in Hamburg: http://npweb.npolar.no/Artikler/2007/1193229250.34
Ozzy Ozone, World Environmental Day (in Norwegian): http://npweb.npolar.no/Artikler/2007/1181122245.59. And: http://www.uneptie.org/ozonaction/information/gallery/ozzygoespolar_thumbs1.htm#norway; http://www.uneptie.org/ozonaction/information/mmc/lib_detail.asp?r=4741.
Tara drift (in Norwegian): http://npweb.npolar.no/Artikler/2007/damocles.
Corrections/Updates to Deliverable information in Annex 1 DoW
- Months per partner were not given correctly in the last version of the DoW. They are updated in the new DoW (months 25-42).
- Deliverable D.1.4-03 is delayed to month 29.
- Regarding contributions from Russian partners in Damocles concerning Task 1.4, no input to the report for months 13-24 was received. However, through S. Sandven (NERSC), two Russian deliverables were added (1.4-08 and -09, see DoW for months 25-42).
