State of the Arctic - Past and present cryosphere
- 15:00 Snow in the changing sea ice systems
Authors: Melinda Webster ( NASA Goddard Space Flight Center ); Sebastian Gerland ( Norwegian Polar Institute ); Marika Holland ( National Center for Atmospheric Research ); Elizabeth Hunke ( Los Alamos National Laboratory ); Ron Kwok ( Jet Propulsion Laboratory ); Olivier Lecomte ( Université Catholique de Louvain ); Robert Massom ( Australian Antarctic Division and Antarctic Climate and Ecosystems Cooperative Research Centre ); Don Perovich ( Thayer School of Engineering, Dartmouth College ); Matthew Sturm ( University of Alaska Fairbanks )
Snow is the most reflective, and also the most insulating, natural material on Earth. Consequently, snow is an integral part of Earth’s climate. Across vast swaths of the polar oceans and beyond, sea ice intercepts snowfall that would otherwise directly enter the ocean. On accumulating, this snow cover significantly modifies the physical and radiative properties of the sea ice environment, which constitutes up to 25% of Earth's snow-covered regions. In this way, snow modulates not only the role of sea ice in the global climate system, but also the sensitivity and response of sea ice to anthropogenic warming.
The spatial and temporal heterogeneity of snow on sea ice poses serious challenges for observing and quantifying the current state of snow on sea ice, monitoring long-term changes in snow conditions and understanding snow-related processes and their feedbacks. This has, in turn, severely limited our ability to realistically represent the coupled snow-sea ice system in climate models, which undermines accurate prediction of future sea ice conditions and their effects in response to climate variability and change. In this work, we survey the snow-ice systems and provide recommendations for overcoming present challenges. This view points toward the importance of constraining uncertainties in observations and collecting process-oriented observations as key steps for advancing our knowledge of snow’s role in the sea-ice systems and improving our understanding of polar climate change. These efforts could be achieved through stronger coordination between the observational, remote sensing and modelling communities, and would pay dividends through distinct improvements in predictions of polar environments.
- 15:15 Effects of near surface air temperature and precipitation on Arctic sea ice thermodynamics and evolution
Authors: Caixin Wang ( Norwegian Polar Institute ); Robert M. Graham ( Norwegian Polar Institute ); Keguang Wang ( Norwegian Meteorological Institute ); Sebastian Gerland ( Norwegian Polar Institute ); Mats A. Granskog ( Norwegian Polar Institute )
Rapid changes are occurring in the Arctic, including a reduction in sea ice thickness and coverage and a shift towards younger and thinner sea ice. The rate of warming in the Arctic is twice as fast as the global average. Snow and sea ice models are often used to study these ongoing changes in the Arctic, and are typically forced by atmospheric reanalyses in absence of observations. ERA5 is a new global reanalysis that will replace the widely used ERA-Interim (ERA-I). In this study, we compare the near surface air temperature at 2 m height (T2M) and precipitation between the two reanalyses and with buoy observations from Arctic sea ice. We then assess how the biases in reanalyses influence the snow and sea ice evolution in the Arctic when used to force a thermodynamic sea ice model. We find that both reanalyses have a warm bias, which is largest when the T2M is lower than -25°C. Surprisingly the warm bias in the new ERA5 (1.6-3.7 °C) is larger than in ERA-I (0.7-2.3 °C) during the cold season despite the finer vertical resolution in ERA5. Total precipitation is usually larger in ERA-I than in ERA5, despite ERA-I being considered one of the driest reanalyses in the Arctic. However, the snowfall products are broadly similar for both, because ERA-I had substantial anomalous Arctic rainfall, which is greatly reduced in ERA5. We next perform simulations with a freezing degree days (FDD) model and 1D thermodynamic sea ice model, applying ERA-I and ERA5 as forcing. These simulations indicate that the warm bias in EAR5 results in a lower ice thickness. However, the lower precipitation in ERA5 produces a thinner snow pack which allows more heat loss to the atmosphere. Thus, the larger warm bias and lower precipitation in ERA5 compensate each other. The net result is a slightly larger ice thickness at the end of growth season compared with using ERA-I forcing. We surmise that the precipitation has a larger influence on the sea ice evolution during the freezing period than the near surface temperature.
- 15:30 28 years of fjord ice coverage in Kongsfjorden, Svalbard, observed by satellite radar
Authors: Malin Johansson ( UiT The Arctic University of Norway ); Eirik Malnes ( Norut ); Sebastian Gerland ( Norwegian Polar Institute ); Hannah Vickers ( Norut ); Tom Rune Lauknes ( Norut ); Anthony Doulgeris ( UiT The Arctic University of Norway ); Anca Cristea ( UiT The Arctic University of Norway ); Dimitry Divine ( Norwegian Polar Institute )
Fjords of Svalbard are partially covered by ice in form of drifting and landfast sea ice, and icebergs from glaciers during winter and spring. Such ice is highly relevant for climate and ecosystem processes. Here we present the seasonal evolution from the last 30 years of fjord ice in Kongsfjorden. Kongsfjorden is located in the north-western part of Spitsbergen. As a pilot study for an extension of existing sea ice monitoring, we have used daylight- and weather-independent satellite radar data to investigate the seasonal sea ice in Kongsfjorden, Svalbard, from 1991–2018. We use satellite images from the ERS-1/2, Envisat, Radarsat-2, and Sentinel-1 synthetic aperture radar (SAR) satellites. The bi-weekly coverage after 2002 enables us to study the seasonal evolution with respect to fractional ice cover and length of the season. The improvements in sensor capabilities over the last 30 years (higher spatial and temporal resolution, dual polarization) allow accurate ice classification for the most recent years on a frequent basis.
All satellite images that covered a chosen area of interest (ca. 220 km2) with Kongsfjorden in the centre were geocoded on a fixed grid. A topographic map was used to mask out the glaciers and land masses. We classify the data by separating the image into segments based on statistical properties of the data. After the segmentation the segments were manually classified as either open water or ice. The years 2002–2005 and 2009–2011 have larger spatial ice extent (160–220 km2) with longer continuous sea ice seasons of more than 150 days compared to the other years after 2002 (60–120 km2and 40–150 days ice season). After the winter of 2011/12 the maximum sea ice extent has in our observations not exceeded 120 km2. Before 2002, the satellite coverage is sparser and estimates for ice extent and length of season are more uncertain.
This work is part of the projects "REmote Sensing of sea ICe and its effects on Ecosystems (RESICE) funded by the Norwegian Ministry of Climate and Environment, and “Mapping Sea Ice”, funded by the Fram Centre in its flagship program Fjords and Coast. Beyond this pilot study, the satellite data set is currently also used in combination with terrestrial radar observations and data from Unmanned Aircraft Systems (UAS) and Unmanned Surface Vehicles (USV) to demonstrate the feasibility of monitoring ice conditions in relation to studies of marine ecology and Arctic climate.
- 15:45 Establishing reference values of natural variations of sea ice, NE Svalbard
Authors: Katrine Husum ( Norwegian Polar Institute ); SImon Belt ( University of Plymouth ); Ulysses Ninnemann ( University of Bergen ); Deniz Koseoglu ( University of Plymouth ); Dmitry Divine ( Norwegian Polar Institute ); Kelly Hogan ( British Antarctic Survey ); Riko Noormets ( UNIS ); Lukas Smik ( University of Plymouth ); Arto Miettinen ( Norwegian Polar Institute )
Today's rapid changes, such as warmer waters entering the Arctic Ocean, make it important to obtain information about natural variations in ocean currents and sea ice in this sensitive region. The sea ice cover and the thickness of the sea ice has changed quickly in recent years. Knowing the past sea conditions is important for establishing natural reference values in order to better understand the causes and consequences of current changes. In this study, we investigated so-called "biomarkers" from sea ice algae and fossil plankton through the last approximately 13,000 years in seafloor sediments northeast of Svalbard. In order to decipher water temperatures in the past, prior to when instrumental measurements were made, we study fossil plankton and fossil animals from cores of seabed sediments. The composition of the fauna and flora is dependent on environmental factors, such as the temperature and salinity of the seawater, allowing us to depict past conditions in the marine environment and water masses. The results show that the sea ice decreases sharply during the cold climate period Younger Dryas and is at a minimum at the beginning of our current interglacial warm period. The data also clearly shows that seasonal season sea ice has been continuously present NE of Svalbard since the last ice age with 10-60% spring sea ice present. These values will be used together with several reconstructions to establish natural reference values for sea ice in this area of the Arctic Ocean. The youngest data point in this study is from 1905, so this reconstruction does not show development over the last approx. 100 years. Trends in modern observations show that over the past 10 years seasons with relatively little sea ice are increasing in frequency. The geographical area of the sea ice cover is shrinking and sea ice is disappearing earlier in the season than has been previously observed. The long-term historical reference values from this study indicate that the current sea ice situation could resemble the conditions just after the last ice age (approximately 9500-9000 years before our time), when changes in the Earth’s orbit and rising Greenhouse gasses drove massive cryosphere retreat. However, unlike that earlier period orbit changes and other natural driving forces cannot explain the current reduction of sea ice suggesting the effects of human activity may already be driving a retreat similar that seen during the last great cryospheric collapse in Earth’s history.
- 16:00 Two decades of Svalbard ice core studies -- progress and remaining challenges
Authors: Elisabeth Isaksson ( Norwegian Polar Institute ); Dmitry Divine ( Norwegian Polar Institute ); Jean-Charles Gallet ( Norwegian Polar Institute ); Tonu Martma ( Tallinn University fo Technology ); Carmen Vega ( University of Costa Rica ); Veijo Pohjola ( Uppsala University ); Mark Hermansson ( Hermanson & Associates LLC ); Meri Ruppel ( University of Helsinki ); Johan Ström ( Stockholm University ); Joana Soares ( Finnish Meteorological Institute ); Isabel Wendl ( Paul Scherrer Institute ); Anja Eichler ( Paul Scherrer Institute ); Dimitri Osmont ( Paul Scherrer Institute ); Margit Schwikowski ( Paul Scherrer Institute )
Over the last two decades, ice cores have been retrieved from three major glacier-ice caps in Svalbard; Lomonosovfonna, Austfonna and Holtedahlfonna. The longest of these cores covers the past 1200 years. Thus, these cores provide information on both the spatial variability component, in addition to the temporal record, of both climate and pollution. We have used the δ18O records to reconstruct the winter surface air temperatures utilizing techniques used in dendrochronology called ‘scaling’. During the 1800s, which according to our results was the coldest century in Svalbard, the Little Ice Age winter cooling was of the order of 4˚C, compared to the 1900s. One of the most striking features of the reconstruction is a lasting pre-1300 period of warm winters, where DJF temperatures were comparable to those that were observed in Svalbard in the 1930s and in the most recent decade. Much effort has been dedicated to identifying the most important sources for pollutants; these data show a clear east-west zonal gradient across the archipelago, with the highest concentrations in the east, suggesting a different origin for air masses arriving in different sectors of Svalbard. Some of our recent work has been involving black carbon (BC). We have analyzed BC in ice cores from both Lomonosovfonna and Holtedahlfonna, using two different methods; a Single Particle Soot Photometer (SP2) was used to measure BC in the core from Lomonosovfonna, while a filter-based method was used to analyze EC (elemental carbon, proxy for BC) on Holtedahlfonna. Both these records clearly show an anthropogenic influence since the beginning of the industrial revolution. Both these BC records follow the general history of use of coal and oil in industrial parts of the world. However, the trends of these records are not in agreement from ca. 1970 onward. The BC record from Lomonosovfonna is peaking between the 1950s and the 1980s, followed by a clear decline since ca. 1970, in agreement with the implementation of cleaner technologies and stricter environmental policies. Following a temporary low point around 1970 the record from Holtedahlfonna shows a pronounced increase in BC deposition from ca. 1970 to 2004, reaching unprecedented values in the 1990s. This increase contradicts the atmospheric monitoring records, among them nearby Zeppelin station. Chemical transport models results suggest that the increase may be caused by enhanced scavenging efficiency of BC due to higher temperatures and precipitation.
- 16:15 The State of Environmental Science in Svalbard (SESS) report - integrating research and monitoring in Svalbard to gain insight into environmental changes in the High Arctic
Authors: Christiane Hübner ( Svalbard Integrated Arctic Earth Observing System (SIOS) ); Heikki Lihavainen ( Svalbard Integrated Arctic Earth Observing System (SIOS) ); Georg Hansen ( Norwegian Institute for Air Research (NILU) ); Hanna Lappalainen ( University of Helsinki ); Elizabeth Orr ( University of Cincinnati ); Inger Jennings ( Svalbard Integrated Arctic Earth Observing System (SIOS) )
The Norwegian archipelago Svalbard in the European High Arctic is an attractive platform for research due to its location, accessibility and rich infrastructure. More than 10 nations have established world-class research infrastructure and conduct intensive research and monitoring programmes. Svalbard is also a place visited by many politicians, government officials and journalists. This combination makes it a suitable place to inform policy makers and the general public about the state of and changes to environmental parameters in the High Arctic.
Svalbard Integrated Arctic Earth Observing System (SIOS) is developing and maintaining a regional observational system in and around Svalbard. It addresses Earth System questions related to global change by bringing together new and existing research infrastructure owned by a large number of international institutions, thereby attracting leading scientists in fields related to Earth System Science.
The State of Environmental Science in Svalbard (SESS) report is the annual report produced by SIOS. It summarises the state of current knowledge of key Earth System Science parameters in the Svalbard region. The SESS report outlines the work that has been done in the previous years within the SIOS cooperation to optimise the observing system and recommends research priorities for the following year(s). It combines the long-term monitoring data that form the core of the SIOS observing system with new, innovative monitoring and research. In addition to evaluating the state of current knowledge, the SESS report highlights the questions that remain unanswered and recommends solutions.
The first SESS report, published January 2019, includes chapters on important topics for assessing the state of the Arctic, including: the state of permafrost across different parts of Spitsbergen; the development of a robust and harmonised monitoring programme for snow; interactions between the ocean and the atmosphere; the state of knowledge about the lower atmosphere and oceans surrounding Svalbard; and the role of microorganisms in climate processes.
In addition to the scientific report, a popular science section will summarise the findings in a visually appealing and easy to understand manner. This summary will be used to communicate with visitors to Svalbard with the aim of engaging both policy makers and the general public and of raising awareness about the scientific activities in Svalbard and the current state of the environment in Arctic regions.
The talk will focus on the key findings from the first SESS report and the recommendations for topics for the next report.
- 16:30 A knowledge base for climate adaptation on Svalbard
Authors: Inger Hanssen-Bauer ( Norwegian Meteorological Institute ); Stein Beldring ( NVE ); Andreas Dobler ( Norwegian Meteorological Institute ); Regula Frauenfelder ( Norwegian Geotechnical Institute ); Eirik Førland ( Norwegian Meteorological Institute ); Hege Hisdal ( NVE ); Ketil Isaksen ( Norwegian Meteorological Institute ); Jack Kohler ( Norwegian Polar Institute ); Stephanie Mayer ( Uni Research ); Anne Britt Sandø ( Institute of Marine Research ); Matthew Simpson ( Norwegian Mapping Authority ); Asgeir Sorteberg ( University of Bergen )
During the last decades rapid climate change in the Svalbard region has led to challenges for the Svalbard communities, both directly and through their impacts on the physical environment. The Norwegian Environment Agency has commissioned an assessment report to provide reliable and up-to-date information relevant for climate adaptation in Svalbard. The Norwegian Centre for Climate Services (NCCS) is responsible for the report, which involves more than 30 authors from 11 institutions.
The report includes descriptions of past, present and projected future climate in terms of variability and changes in meteorological, hydrological, cryospheric and oceanic variables. Furthermore, the report provides information on storm surges, landslides and avalanches.
Information contained in this report is fully referenced and based mainly on research and monitoring efforts published the last two decades. Historical descriptions are based upon observations, and, for the atmosphere also on reanalysis. Future climate descriptions are to a large degree based upon an assessment of available atmospheric and oceanic regional projections. However, the report also includes some new regional to local scale model results for the Svalbard area:
- - A high emission scenario (RCP 8.5) projection has been downscaled to 2.5x2.5 km resolution using a regional climate model. Likewise, the ocean in the North Atlantic-Arctic region has been downscaled for the stabilization scenario (RCP 4.5)
- - Empirical statistical methods have been applied to downscale 2 m temperature from all CMIP5 models in order to estimate an uncertainty range
- - Hydrological models have been applied with input from Arctic-CORDEX models to project changes in hydrological variables.
This presentation will give a brief overview of the contents and the main conclusions in the report.
- 16:45 Future sea-level change from past Arctic glacier mass loss commitments
Authors: Ben Marzeion ( University of Bremen ); Georg Kaser ( University of Innsbruck ); Fabien Maussion ( University of Innsbruck ); Nicolas Champollion ( University of Bremen )
Even though glaciers store less than 1% of the global ice mass, they have probably been the strongest contributor to sea-level change in the 20th century, with the Arctic contributing the greatest fraction. While mass loss from the ice sheets and thermal expansion of the ocean water are quickly increasing, Arctic glaciers will continue to play an important role in sea-level change in the 21st century. Understanding the causes, mechanisms and time scales of glacier change is therefore of paramount importance for identifying successful strategies for mitigation of, and adaption to, climate change. In this presentation, we show that much of the future glacier-mass loss will be a response to climate change caused by past greenhouse-gas emissions. Mitigating climate change through reduced greenhouse-gas emissions therefore only has a limited influence on glaciers in the 21st century, while strongly impacting their long-term response. We will further show that currently, each emitted 1 kg of carbon dioxide will eventually lead to 10 ± 5 kg of ice-mass loss from glaciers.
Wednesday 23rd January 2019
15:00 - 17:00