24 February 2023 | 14:00 - 15:30 (GMT+1)
Open Session - HYBRID
Room: Hörsaal 1
Session Conveners: Suchithra Sundaram (Independent Researcher, India); Clare Eayrs (Korean Polar Research Institute); Jakob Abermann (Univerity of Graz)
The Earth's north pole, the Arctic, started exhibiting climatic changes since the beginning of the satellite era, particularly a declining trend in sea ice extent. Among the Arctic regions, exceptional sea ice melt occurs in the Western Arctic over the Chukchi-Beaufort Sea region. Observational and climate modeling studies claim that anthropogenic drivers, as well as the internal variability of the climate system, contribute to these observational trends in the Arctic sea ice decline. The sea ice over the polar regions plays a significant role in the regional and global climate system. Its impact on the lower latitudes is through the teleconnections associated with the various ocean- atmosphere-cryosphere processes. High-resolution geological and ice core records show that the regional and global teleconnections between Arctic regions and lower latitudes existed in the past too. But they are poorly understood in the climatic contexts that are substantially different from today.
Paleoclimate records show that the ice sheets over the Northern Hemisphere, other than the present-day ice sheets, have played significant roles in the global climate in the past. Hence efforts are needed at both observational and modeling levels to improve multi-centennial projections of Arctic and global climate evolution by combining the current knowledge of climatic variability and those during the paleo periods. This session invites contributions on observational and modeling studies of the Arctic related to the past, present, and future. The abstracts for the session include and are not limited to the factors associated with the regional climate variability of the Arctic: Arctic Amplification, ice-albedo feedback, Beaufort Gyre, Permafrost, Polar Vortex, and the various Ocean- Atmosphere-Cryosphere processes that link the Arctic with lower latitudes: Monsoon, North Atlantic Oscillation, Northern Annular Mode/Arctic Oscillation, Atlantic Multi Decadal Oscillation, Elnino Southern Oscillation, Pacific Decadal Oscillation, Indian Ocean Dipole, Global thermohaline circulation.
unfold_moreReconnaissance of Alfred Wegener’s West Greenland Expedition: bridging a century of climate change work: 1929 to 2022
Jakob Abermann1; Wolfgang Schöner1; Andreas Truegler2; Florina Schalamon1; Sebastian Scher2; Robert Fausto3; Baptiste Vandecrux3
1Graz University; 2Know Center Austria; 3GEUS
The cryosphere in Greenland is currently undergoing strong changes. While remote sensing improves our understaning of spatial and temporal changes across scales for recent decades, particularly our knowledge during the pre-satellite era is scarce and thus valuable in a climate change perspective. At Graz University, the last work-place of Alfred Wegener, we have access to the extensive expedition results from their epic 1929-1931 expedition to Greenland. This coincides with a particularly warm phase particularly in the Arctic. Local conditions at the Qaamerujup glacier have changed dramatically since then with a length reduction of more than 2 km, a rise in terminus position and thickness reduction by several hundred meters. During a reconnaissance expedition in summer 2022 we installed autonomous weather and ablation stations at the same locations as Wegener did in the 1930s, based on their excellent documentation. In order to connect the ablation rates at the changed surface conditions over the course of a century, we performed innovative UAV-based atmospheric measurements. In addition to the in-situ work, we challenge reanalysis products with high-quality ground-truthing from the pre-satellite aera. Applying machine learning algorithms, we assess the potential for using historical meteorological and glaciological data together with reanalysis products and contemporary measurements in order to determine long-term geometrical feedback processes.
unfold_moreUnderstanding response of seasonal hydrology to Arctic Amplification: tree-ring modeling of Siberian Arctic flow for the last 250 years
Irina Panyushkina1; David Meko1; Richard Thaxton2; Vladimyr Myglan; Leonid Agafonov; Alexander Shiklomanov3
1University of Arizona; 2University of Idaho; 3University of New Hampshire
Arctic climate is uniquely sensitive to changes in climate forcing, yet it also has large internal variability that is important to understand. Our research focuses on characterizing the climatic system perturbation with tree-ring proxies and quantifying the response of local hydrology to Arctic Amplification. The sparsity of gauged observations and gaps in the records lead to bias and uncertainty in modeling Arctic river flow, which greatly contributes fresh water and heat to the Arctic Ocean and impacts the sea ice dynamics. Tree-ring networks of the two largest Siberian rivers, the Ob and the Yenisei, are used to estimate the long-term trend in the seasonal and annual discharge. The modeling results are compared with water balance and hydrograph routing modeling for the Anthropocene. We discuss the possible impacts of fast-track permafrost thawing and an intensified regime of boreal forest fires on the irregularity and unprecedented changes in hydrology across the Ob and Yenisei River basins. The variability of Siberian flow over the past 250 years represents positive feedback of river hydrology to Arctic warming. The winter flow has particularly increased (up to 70%) in the last 25 years since Arctic Amplification has been reported. The discharge changes linked to the initial response to climate change are amplified by internal perturbations in the system via permafrost degradation and forest fires. We look for possible implications of our modeling results to solving practical problems of ecological, economic, or social systems in the Arctic.
unfold_moreImpact of variability in cold content and water content of snowpack on mass balance over Vestre Broggerbreen Glacier, Ny-Alesund, Svalbard
National Centre for Polar and Ocean Research
Over the past few decades, many Arctic glaciers have been shrinking in response to climate change and are predicted to shrink further over the next few decades. We have been monitoring Vestre Broggerbreen glacier since 2011 for glacier dynamics, including mass balance, surface flow, ice flux and terminal movement. We carried out a detailed investigation on temporal variability in cold content and water content in snowpack during spring 2011-2019, using thermister string and snow fork, respectively. We have also used a sledge-mounted 400 MHz ice radar to map the thickness of the snowpack across the glacier. The present study highlighted the significant reduction (>18%) in cold content and a radical increase in water content (>12%) in snowpack during the above said eight years period. Reduction in the cold content (10%) of snowpack accelerated early ice melting and potentially enhanced the glacier mass loss (6%) over the Vestre Broggerbreen glacier. The increased liquid precipiation and temperature during the early snow season in recent times have enhanced the mass loss over this glacier.
unfold_moreClimatic impacts of black carbon and dust in the Arctic cryosphere
Finnish Meteorological Institute
Black carbon (BC) and mineral dust are short lived climate forcers (SLCF). In the atmosphere, the radiative effect of these absorbing aerosols is shorter. When BC and dust deposit on snow and ice, their impact is longer and can last until snow and ice, or glaciers and ice caps, are totally melted. We have investigated BC in the Arctic cryosphere, north of 60 deg N. We have found that BC can intiate and enhance melt in extremely small amounts, in ppb, via the albedo feedback mechanism. We have also found that mineral dust can either increase melt in small amounts or act as an insulator and prevent ice and snow from melting in larger amounts. Most recently, we have identified climatically and environmentally significant new northern high latitude dust sources. We have suggested and given evidence supporting a northern HLD belt, defined as the area north of 50deg N, with a “transitional HLD-source area” extending at latitudes 50–58 deg N in Eurasia and 50–55deg N in Canada and a “cold HLD-source area” including areas north of 60 deg N in Eurasia and north of 58 deg N in Canada, with currently “no dust source” area between the HLD and low-latitude dust (LLD) dust belt, except for British Columbia.
Reference: Meinander et al. Newly identified climatically and environmentally significant high latitude dust sources, ACP, https://doi.org/10.5194/acp-2021-963, accepted, 2022.
unfold_moreA new multi-decadal 2.5 km climate simulation over Svalbard
Oskar Landgren1; Julia Lutz1; Andreas Dobler1; Ketil Isaksen1
1Norwegian Meteorological Institute
High-resolution climate model data is important for assessing the impact of climate change. Located in the Nordic Arctic Region, Svalbard is an interesting laboratory for studying the cryosphere, with its location at the sea ice edge, documented very strong warming trends, advanced observing systems and challenging geographical features such as steep topography, glaciers and snow. To properly study changes in certain aspects of the cryosphere, including permafrost, continuous simulations over longer timescales and fine spatial resolution are needed. In addition, simulations like these also enable a better assessment of multi-decadal variability. We present a new high-resolution climate simulation for years 1991 to 2060 produced by the regional climate model system HCLIM for the future strong warming/business-as-usual scenario SSP5-8.5. The model setup consists of convection-permitting HARMONIE-AROME atmospheric physics, SURFEX land surface model with ISBA-ES snow-scheme and SICE prognostic sea ice scheme with snow on sea-ice. The climate projection is based on data from the NorESM2-MM earth system model under the SSP5-8.5 scenario. We present an outlook of the results, with particular emphasis on the importance of decadal variability, including changes in the distribution of rain and snow.